Air-cooled Power Converter

Abstract

A power converter including a busbar, a transistor, and a heat pipe. The transistor includes first and second terminals through which current is transferred when the first transistor is activated, and a gate terminal for controlling the transistor. The terminals are thermally and electrically connected to the busbar. The heat pipe is thermally connected to the first busbar.

Description

[Background technology]

[0001] A power converter is a device that converts power. An "inverter" is one type of power converter. An inverter converts direct current (DC) power to alternating current (AC) power. A "rectifier" is another type of power converter. A rectifier converts AC power to DC power. A DC-DC converter (e.g., a buck, boost, or buck / boost converter) converts DC power at one voltage level to DC power at another voltage level. An AC-AC converter (such as a variable frequency drive controller) converts one form of AC power to another form of AC power. Some AC-AC converters, which may include a DC link electrically connected between the rectifier and the inverter, convert input AC power of one frequency to output AC power of another frequency.

[0002] The present technology may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent Application No. 17 / 191805 [Non-patent literature]

[0004] [Non-Patent Document 1] Electrical and Electronics Technical Team (EETT) Roadmap for October 2017 [Brief description of the drawings]

[0005] [Figure 1a] FIG. 2 illustrates relevant components of an exemplary three-phase inverter. [Figure 1b] FIG. 4 is a timing diagram illustrating exemplary gate control signals. [Figure 1c] FIG. 2 illustrates relevant components of an exemplary three-phase rectifier. [Figure 2a-1] FIG. 1 illustrates an isometric view of an exemplary packaged switch. [Figure 2a-2] FIG. 2 is a reverse isometric view of an exemplary packaged switch. [Figure 2b-1] FIG. 2 is an isometric view of an exemplary packaged half-bridge. [Figure 2b-2] FIG. 2 is a reverse isometric view of an exemplary packaged half-bridge. [Figure 2b-3] FIG. 2b-1 and FIG. 2b-2 show the example packaged half-bridges with terminals electrically connected by metal straps. [Figure 2c-1] FIG. 1 illustrates an isometric view of an exemplary packaged switch. [Figure 2c-2] FIG. 2 is a reverse isometric view of an exemplary packaged switch. [Figure 2d-1] FIG. 1 illustrates an isometric view of an exemplary packaged switch. [Figure 2d-2] FIG. 2 is a reverse isometric view of an exemplary packaged switch. [Figure 2e-1] FIG. 1 illustrates an isometric view of an exemplary packaged switch. [Figure 2e-2] FIG. 2 is a reverse isometric view of an exemplary packaged switch. [Figure 3a-1] FIG. 3 illustrates relevant components of one embodiment of the packaged switch shown in FIGS. 2a-1 and 2a-2. [Figure 3a-2] FIG. 3a-2 is a side view of the packaged switch shown in FIG. 3a-1. [Figure 3a-3] FIG. 3a-2 is a rear view of the packaged switch shown in FIG. 3a-1. [Figure 3a-4] FIG. 2 illustrates relevant components of an exemplary switch controller. [Figure 3a-5] FIG. 2 illustrates relevant components of an exemplary switch. [Figure 3a-6] FIG. 2 illustrates relevant components of an exemplary switch. [Figure 3a-7]FIG. 2 illustrates relevant components of an exemplary gate driver. [Figure 3a-8] FIG. 2 illustrates relevant components of an exemplary packaged switch as viewed from above. [Figure 3a-9] FIG. 9 is a side view of the packaged switch shown in FIG. 3a-8. [Figure 3b-1] FIG. 2 illustrates relevant components of an exemplary packaged switch as viewed from above. [Figure 3b-2] FIG. 3b-1 is a side view of the packaged switch shown in FIG. [Figure 3b-3] FIG. 3b-1 is a rear view of the packaged switch shown in FIG. [Figure 3c-1] FIG. 2 illustrates relevant components of an exemplary packaged switch as viewed from the side. [Figure 3c-2] FIG. 3C-1 is a rear view of the packaged switch shown in FIG. [Figure 3d-1] FIG. 2 illustrates relevant components of an exemplary packaged switch as viewed from the side. [Figure 3d-2] FIG. 3d-2 is a rear view of the packaged switch shown in FIG. [Figure 3e-1] FIG. 2C illustrates relevant components of one embodiment of the packaged switch shown in FIGS. 2C-1 and 2C-2. [Figure 3e-2] FIG. 3e-2 is a rear view of the packaged switch shown in FIG. 3e-1. [Figure 3f-1] FIG. 2 illustrates relevant components of an exemplary packaged switch as viewed from the side. [Figure 3f-2] FIG. 3f-1 is a rear view of the packaged switch shown in FIG. [Figure 3g-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3g-2] FIG. 3g-1 is a side view of the switch module shown in FIG. [Figure 3g-3]FIG. 3g-2 is a rear view of the switch module and related components shown in FIG. 3g-1. [Figure 3h-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3h-2] FIG. 3h-2 is a side view of the switch module shown in FIG. [Figure 3h-3] 3h-1 is a rear view of the switch module shown in FIG. 3h-1. [Figure 3i-1] FIG. 2 illustrates exemplary relevant components of a switch module as viewed from above. [Figure 3i-2] FIG. 3i-2 is a side view of the switch module shown in FIG. 3i-1. [Figure 3i-3] FIG. 3i-2 is a rear view of the switch module shown in FIG. 3i-1. [Figure 3j-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3j-2] FIG. 3j-2 is a side view of the switch module shown in FIG. [Figure 3j-3] FIG. 3j-1 is a rear view of the switch module shown in FIG. [Figure 3k-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3k-2] FIG. 3k-1 is a bottom view of the switch module shown in FIG. [Figure 3k-3] FIG. 3k-1 is a side view of the switch module shown in FIG. [Figure 3k-4] FIG. 3k-1 is a rear view of the switch module shown in FIG. [Figure 3l-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3l-2] FIG. 3l-2 is a bottom view of the switch module shown in FIG. [Figure 3l-3] 3l-2 is a side view of the switch module shown in FIG. 3l-1. FIG. [Figure 3l-4] 3l-2 is a rear view of the switch module shown in FIG. 3l-1. FIG. [Figure 3m-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3m-2] FIG. 3l-2 is a bottom view of the switch module shown in FIG. [Figure 3m-3] 3l-2 is a side view of the switch module shown in FIG. 3l-1. FIG. [Figure 3m-4] 3l-2 is a rear view of the switch module shown in FIG. 3l-1. FIG. [Figure 3n-1] FIG. 2 illustrates relevant components of an exemplary switch module from a top view. [Figure 3n-2] FIG. 3l-2 is a bottom view of the switch module shown in FIG. [Figure 3n-3] 3l-2 is a side view of the switch module shown in FIG. 3l-1. FIG. [Figure 3n-4] 3l-2 is a rear view of the switch module shown in FIG. 3l-1. FIG. [Figure 3p-1] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-2] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-3] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-4] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-5] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-6] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-7] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-8] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-9] FIG. 2C illustrates components of an exemplary switch module that can be used in the packaged switch of FIG. 2d-1 or FIG. 2e-1. [Figure 3p-10] FIG. 2 illustrates components of an exemplary switch module. [Figure 3p-11] FIG. 2 illustrates components of an exemplary switch module. [Figure 4a-1] FIG. 2B is a side view of relevant components of one embodiment of the packaged half-bridge shown in FIGS. 2B-1 and 2B-2. [Figure 4a-2] FIG. 4a-1 is a rear view of the packaged half-bridge shown in FIG. [Figure 4b-1] FIG. 2 illustrates the relevant components of an exemplary packaged half-bridge as viewed from the side. [Figure 4b-2] FIG. 4b-1 is a rear view of the packaged half-bridge shown in FIG. [Figure 4b-3] FIG. 4b-1 is a top view of the packaged half-bridge shown in FIG. 4b-1 together with an opaque case. [Figure 4c-1] FIG. 2 illustrates the relevant components of an exemplary packaged half-bridge as viewed from the side. [Figure 4c-2] FIG. 4C-1 is a rear view of the packaged half bridge shown in FIG. [Figure 4c-3] FIG. 4c-1 is a top view of the packaged half-bridge shown in FIG. 4c-1 together with an opaque case. [Figure 4d-1] FIG. 2 illustrates the relevant components of an exemplary packaged half-bridge as viewed from the side. [Figure 4d-2]FIG. 4d-1 is a rear view of the packaged half bridge shown in FIG. [Figure 4d-3] FIG. 4d-1 is a top view of the packaged half bridge shown in FIG. 4d-1 together with an opaque case. [Figure 4e-1] FIG. 2 is a side view of relevant components of an exemplary packaged half-bridge. [Figure 4e-2] FIG. 4e-1 is a rear view of the packaged half bridge shown in FIG. [Figure 4e-3] FIG. 4e-1 is a top view of the packaged half-bridge shown in FIG. 4e-1 with an opaque case. [Figure 4f-1] FIG. 2 illustrates the relevant components of an exemplary packaged half-bridge as viewed from the side. [Figure 4f-2] FIG. 4f-1 is a top view of the packaged half-bridge shown in FIG. 4f-1 together with an opaque case. [Figure 4g-1] FIG. 2b-1 and FIG. 2b-2 are side views of relevant components of one embodiment of the packaged half-bridge shown in FIGS. [Figure 4g-2] FIG. 4g-1 is a rear view of the packaged half bridge shown in FIG. [Figure 4h-1] FIG. 2 illustrates the relevant components of an exemplary packaged half-bridge as viewed from the side. [Figure 4h-2] FIG. 4h-1 is a rear view of the packaged half bridge shown in FIG. [Figure 5a-1] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5a-2] FIG. 5a-2 is a bottom view of the air-cooled inverter system of FIG. 5a-1. [Figure 5a-3] FIG. 5a-2 is a side view of the air-cooled inverter system of FIG. 5a-1. [Figure 5a-4] FIG. 5a-2 is a side view of the air-cooled inverter system of FIG. 5a-1. [Figure 5a-5]FIG. 5a-2 is a diagram showing the air-cooled inverter system of FIG. 5a-1 as viewed from above. [Figure 5a-6] FIG. 2 is a cut-away cross-sectional view of an exemplary heat pipe. [Figure 5a-7] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5a-8] FIG. 8 is a bottom view of the air-cooled inverter system of FIG. 5a-7. [Figure 5a-9] FIG. 8 illustrates electrically insulated heat fins used in the inverter system of FIGS. 5a-7. [Figure 5a-10] FIG. 2 illustrates relevant components of an exemplary air-cooled rectifier system from a bottom view. [Figure 5a-11] FIG. 5a-11 is an end view of the air-cooled rectifier system of FIGS. [Figure 5b-1] FIG. 2 is an end view of relevant components of an exemplary air-cooled inverter system. [Figure 5b-2] FIG. 5b-1 shows the air-cooled inverter system of FIG. 5b-1 as viewed from the bottom. [Figure 5b-3] FIG. 5b-1 is a side view of the air-cooled inverter system of FIG. [Figure 5b-4] FIG. 5b-1 is a side view of the air-cooled inverter system of FIG. [Figure 5b-5] FIG. 5b-1 illustrates exemplary signals and voltages supplied to or received from the air-cooled inverter system of FIG. [Figure 5b-6] FIG. 2 illustrates relevant components of an exemplary air-cooled rectifier system from an end view. [Figure 5b-7] FIG. 5a-11 is a bottom view of the air-cooled rectifier system of FIG. [Figure 5c-1] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5c-2] FIG. 5c-1 is a bottom view of the air-cooled inverter system of FIG. [Figure 5c-3]FIG. 5c-1 is a side view of the air-cooled inverter system of FIG. [Figure 5c-4] FIG. 5c-1 is a side view of the air-cooled inverter system of FIG. [Figure 5d-1] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5d-2] FIG. 5d-1 is a bottom view of the air-cooled inverter system of FIG. [Figure 5d-3] FIG. 5a-2 is a side view of the air-cooled inverter system of FIG. 5a-1. [Figure 5d-4] FIG. 5a-2 is a side view of the air-cooled inverter system of FIG. 5a-1. [Figure 5d-5] FIG. 2 illustrates relevant components of an exemplary air-cooled rectifier system from an end view. [Figure 5d-6] FIG. 5d-5 is a bottom view of the air-cooled rectifier system of FIG. [Figure 5e-1] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5e-2] FIG. 5e-1 is a bottom view of the air-cooled inverter system of FIG. [Figure 5e-3] FIG. 5e-1 is a side view of the air-cooled inverter system of FIG. [Figure 5e-4] FIG. 5e-1 is a side view of the air-cooled inverter system of FIG. [Figure 5e-5] FIG. 2 illustrates relevant components of an air-cooled rectifier system from an end view. [Figure 5e-6] FIG. 2 illustrates the relevant components of the air-cooled rectifier system from a bottom view. [Figure 5f-1] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5f-2] FIG. 5f-1 is a bottom view of the air-cooled inverter system of FIG. [Figure 5f-3] FIG. 2 illustrates relevant components of an air-cooled rectifier system from an end view. [Figure 5f-4] FIG. 5f-3 is a bottom view of the air-cooled rectifier system of FIG. [Figure 5f-5] FIG. 2 illustrates a bottom view of an exemplary passive rectifier. [Figure 5f-6] FIG. 2 illustrates relevant components of an exemplary air-cooled inverter system from an end view. [Figure 5f-7] FIG. 5f-1 is a bottom view of the air-cooled inverter system of FIG. [Figure 5g-1] FIG. 2 illustrates the relevant components of the air-cooled rectifier system from a bottom view. [Figure 5g-2] FIG. 5g-1 is a side view of the air-cooled rectifier system of FIG. [Figure 5g-3] FIG. 2 illustrates the relevant components of the air-cooled rectifier system from a bottom view. [Figure 5g-4] FIG. 5g-3 is a side view of the air-cooled rectifier system of FIG. [Figure 5h-1] FIG. 2 is a bottom view of relevant components of an exemplary air-cooled inverter system. [Figure 5h-2] FIG. 5h-1 is a diagram showing relevant components of the air-cooled inverter system as viewed from the end. [Figure 5i-1] FIG. 2 is an end view of relevant components of an exemplary air-cooled inverter system. [Figure 5i-2] FIG. 5i-1 is a bottom view of the air-cooled inverter system of FIG. [Figure 5i-3] FIG. 2 illustrates the relevant components of the air-cooled rectifier system from a bottom view. [Figure 5i-4] FIG. 2 illustrates relevant components of an air-cooled rectifier system from an end view. [Figure 5i-5] FIG. 2 is a diagram showing the configuration of an air-cooled rectifier as viewed from an end. [Figure 5j-1] FIG. 2 is an end view of an example variable frequency driver controller. [Figure 5j-2] FIG. 2 is an end view of an example variable frequency driver controller. [Figure 5j-3] FIG. 2 is a bottom view of an exemplary variable frequency driver controller. [Figure 5j-4] FIG. 2 is a side view of an exemplary variable frequency driver controller. [Figure 5j-5] FIG. 2 is a side view of an exemplary variable frequency driver controller. [Figure 5k] FIG. 2 is a bottom view of an exemplary power converter. [Figure 5l] FIG. 2 is a bottom view of an exemplary power converter. [Figure 5m] FIG. 2 is a bottom view of an exemplary power converter. [Figure 5n] FIG. 2 is a bottom view of an exemplary power converter. [Figure 5o] FIG. 2 is a bottom view of an exemplary power converter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] Use of the same reference numbers in different figures indicates similar or identical items. In most cases, a reference number in the text without a letter and / or number following the reference number refers to any or all elements in the figure to which the reference number is attached. For example, the reference number "204" refers to 204, 204L, 204H, 204L-1, etc., and the reference number "204L" refers to 204L, 204L-1, etc.

[0007] Power converters include inverters, rectifiers, etc. Although the present disclosure is described primarily with reference to inverters and rectifiers, it will be understood that the present disclosure is applicable to other types of power converters.

[0008] The inverters and rectifiers of the present disclosure can be bidirectional. A bidirectional inverter can convert DC power to AC power while operating in a forward direction and convert AC power to DC power while operating in a reverse direction. Similarly, a bidirectional rectifier can convert AC power to DC power while operating in a forward direction and convert DC power to AC power while operating in a reverse direction.

[0009] Inverters and rectifiers come in a variety of designs. For example, inverters and rectifiers can have one, two, three or more phases. Typically, each phase includes a "high-side switch" electrically connected to a "low-side switch." When the switches are turned on (i.e., activated), they conduct electricity.

[0010] 1A shows the relevant components of a three-phase inverter 100 that can be used to convert DC power from a battery to three-phase AC power for use by an electric motor. Each phase includes a high-side switch connected to a low-side switch. Each high-side switch includes an insulated gate bipolar transistor (IGBT) THx connected in parallel with a diode DHx, and each low-side switch includes an IGBT TLx connected in parallel with a diode DLx.

[0011] The high-side IGBTs TH1 to TH3 are connected in series with the low-side IGBTs TL1 to TL3 via nodes N1 to N3, respectively, which are connected to the terminals of the inductive elements Wa to Wc. For convenience of explanation, the inductive elements Wa to Wc are formed in the stator windings of a synchronous or asynchronous motor of an electric vehicle (EV).

[0012] The collectors of TH1-TH3 and the cathodes of DH1-DH3 are connected to each other and to the V+ input terminal, and the emitters of TL1-TL3 and the anodes of diodes DL1-DL3 are connected to each other and to the V- input terminal. A DC voltage Vdc is received between the V+ and V- input terminals from a battery or other DC power source.

[0013] The high-side IGBTs TH1-TH3 and low-side IGBTs TL1-TL3 are controlled by microcontroller 110 via gate drivers H101-H103 and L101-L103, respectively. A gate driver is a circuit that accepts low-power input signals from a device (e.g., a microcontroller) and generates corresponding high-power output signals required to activate the power transistors.

[0014] Control of the IGBTs is relatively simple. The high-side gate drivers H101-H103 and the low-side gate drivers L101-L103 receive driver control signals (e.g., pulse width modulation signals PWM-H1-PWM-H3 and PWM-L1-PWM-L3) from the microcontroller 110. When the PWM-H1-PWM-H3 signals are asserted, the high-side gate drivers H101-H103 assert high-power gate control signals VgH1-VgH3, respectively, to activate the high-side IGBTs TH1-TH3, respectively. When the PWM-L1-PWM-L3 signals are asserted, the low-side gate drivers L101-L103 assert high-power gate control signals VgL1-VgL3, respectively, to activate the low-side IGBTs TL1-TL3, respectively. Each of the IGBTs TH1-TH3 and TL1-TL3 conducts current to or from the stator winding W to which it is connected when activated.

[0015] By the coordinated activation of the high-side IGBT and the low-side IGBT, the direction of the current in the stator winding can be switched continuously and regularly, so that the current flows into or out of the winding. FIG. 1b shows an example timing diagram of the gate control signals VgH1-VgH3 and VgL1-VgL3. This timing diagram is provided only to facilitate a basic understanding of inverter control. In practice, more complicated timing patterns are used to control the inverter.

[0016] The microcontroller 110 controls the high-side IGBTs TH1-TH3 and the low-side IGBTs TL1-TL3 via the PWM-H1-PWM-H3 and PWM-L1-PWM-L3 signals, respectively. Microcontrollers such as the microcontroller 110 and other similar data processing devices may include a central processing unit (CPU), a memory that stores instructions executable by the CPU, and peripherals such as timers, input / output (I / O) ports, etc. The microcontroller 110 generates the PWM-H1-PWM-H3 and PWM-L1-PWM-L3 signals based on the CPU-executable instructions stored in the memory. The gate drivers H101-H103 generate the VgH1-VgH3 signals based on the PWM-H1-PWM-H3 signals, and the gate drivers L101-L103 generate the VgL1-VgL3 signals based on the PWM-L1-PWM-L3 signals. The microcontroller 110 may adjust the duty cycle and / or period of a pulse width modulated (PWM) signal according to instructions stored in memory.

[0017] FIG. 1c shows relevant components of a three-phase rectifier 150 that can be used to convert three-phase AC power from a power grid to DC power for charging an EV battery. The inverter 100 and the rectifier 150 are substantially similar. Like the inverter 100, each phase of the rectifier 150 includes a high-side switch connected to a low-side switch. Each high-side switch includes an IGBT THx connected in parallel with a diode DHx, and each low-side switch includes an IGBT TLx connected in parallel with a diode DLx. The high-side IGBTs TH1-TH3 are connected in series with the low-side IGBTs TL1-TL3 via nodes N1-N3, respectively, and are connected to respective terminals of the inductive elements La-Lc, respectively. For ease of explanation, the inductive elements La-Lc take the form of inductors of an LCL filter 162, which is also coupled to a three-phase AC power source 164.

[0018] The collectors of TH1 to TH3 and the cathodes of DH1 to DH3 are connected to each other and to a V+ output terminal, and the emitters of TL1 to TL3 and the anodes of the diodes DL1 to DL3 are connected to each other and to a V- output terminal.

[0019] The high-side IGBTs TH1-TH3 and the low-side IGBTs TL1-TL3 are controlled by a rectifier controller 160 via gate drivers H101-H103 and L101-L103, respectively. Through coordinated activation of the high-side and low-side IGBTs, the rectifier 150 provides a rectified DC voltage Vrdc at output terminals V+ and V-, which may be connected to an isolated DC / DC converter or other device that may utilize one or more aspects of the present disclosure. Although not shown, a filter may be connected between the output terminals V+ and V- to smooth Vrdc before being supplied to another device, such as an isolated DC / DC converter.

[0020] Although inverter 100 and rectifier 150 are similar, there is at least one difference. Rectifier 150 includes a controller 160, which may include a phase-locked loop (PLL) and other components for synchronizing control of high-side IGBTs TH1-TH3 and low-side IGBTs TL-1-TL-3 to the frequency (e.g., 60 Hertz) of three-phase AC input power provided by power source 164. Controller 160 may also include a CPU and memory that stores CPU-executable instructions that may be substantially different from the CPU-executable instructions stored in memory of microcontroller 110 of inverter 100. Similar to microcontroller 110, controller 160 generates PWM-H1-H3 and PWM-L1-L3 signals. The gate drivers H101 to H103 generate the VgH1 to VgH3 signals based on the PWM-H1 to PWM-H3 signals, and the gate drivers L101 to L103 generate the VgL1 to VgL3 signals based on the PWM-L1 to PWM-L3 signals. The controller 160 can adjust the duty cycle and / or period of the PWM signals.

[0021] EVs, DC fast charging stations, variable frequency drive controllers for industrial machines (e.g., industrial pumps, fans, compressors, etc.), electric vertical take-off and landing (eVTOL) aircraft, etc. utilize large and heavy power converters. There is a demand for smaller and lighter power converters with high power density (i.e., power / volume). For example, the October 2017 "Electrical and Electronics Technical Team (EETT) Roadmap," published in part by the U.S. Department of Energy, sets a 2025 power density target of 100 kW / L for EV inverters. The 2017 EETT Roadmap states that "To achieve the 2025 EETT R&D target, power density must be improved by 800% compared to the 2015 EETT R&D technology target and by more than 450% compared to current on-road technology."

[0022] Power converters in general and their power transistors can operate at extremely high temperatures. A cooling system is often required to cool the power converter. The cooling system often includes an expensive electromechanical pump that circulates the coolant between the converter and a radiator where heat exchange occurs. Unfortunately, the electromechanical pump can fail. The electromechanical pump also draws power from the battery of vehicles such as EVs and eVTOLs, thereby reducing the overall range. The liquid cooling system also requires tubing that fluidly connects the electromechanical pump, the converter, and the radiator. These tubing can become clogged or leak, which can lead to a shutdown of the converter if enough coolant leaks out of the system or if the flow of liquid is obstructed. Additionally, the electromechanical pump and tubing add weight, volume, cost, and complexity to the systems in which they are utilized, such as EVs, eVTOLs, and DC fast charging stations.

[0023] An "air-cooled converter" is disclosed that includes an "air-cooled inverter" and an "air-cooled rectifier." Although the disclosure is described primarily in the context of an air-cooled inverter and an air-cooled rectifier, it will be understood that the disclosure is applicable to other types of air-cooled power converters, such as an "air-cooled DC / DC converter" or an "air-cooled AC / AC converter."

[0024] The air-cooled inverter (hereinafter also referred to as the air-cooled inverter system) and the air-cooled rectifier (hereinafter also referred to as the air-cooled rectifier system) indirectly cool the power transistors using heat pipes. The power density of the disclosed air-cooled inverter meets or potentially exceeds the 100 kW / L target set forth in the 2017 EETT Roadmap mentioned above.

[0025] A "switch module" is disclosed. The switch module includes a "power stack." The power stack may include a "switch" sandwiched between a "die substrate" and a metal conductor called a "die clip" that is electrically and thermally connected to the die substrate. The switch may include one or two or more power transistors.

[0026] The switch modules may also include a "switch controller." The switch controller controls the respective switches (i.e., activates or deactivates the switches). When activated, the switches conduct between their two current terminals. The switch controller may perform other functions, such as monitoring the switches for fault conditions (e.g., an electrical short between the current terminals). The switch modules may include one or more additional components, such as resistors, capacitors, diodes, current sensor circuits, temperature sensor circuits, voltage sensor circuits, voltage regulators, etc.

[0027] A "packaged switch module" is disclosed. The packaged switch module can include one or more switch modules. Although the packaged switch module can be used in the air-cooled inverter and air-cooled rectifier of the present disclosure, it is understood that the packaged switch module can be used in a variety of other applications, such as an air-cooled DC / DC converter or an air-cooled AC / AC converter.

[0028] A packaged switch module that includes only one switch module is called a "packaged switch."

[0029] A packaged switch module that contains two switch modules is called a “packaged half-bridge.” The switches may or may not be electrically connected within the packaged half-bridge.

[0030] (Packaged switches and packaged half-bridges) The packaged switches and packaged half-bridges can essentially be cube-shaped with six sides: top, bottom, front, back, left side and right side. Some packaged switches can fit into industry standard package configurations such as the TO-247 package.

[0031] 2a-1 and 2a-2 are isometric and reverse isometric views of an example packaged switch 200. FIGs. 2b-1 and 2b-2 are isometric and reverse isometric views of an example packaged half-bridge 250. FIGs. 2c-1 and 2c-2 are isometric and reverse isometric views of an example packaged switch 211. FIGs. 2d-1 and 2d-2 are isometric and reverse isometric views of an example packaged switch 247s. FIGs. 2e-1 and 2e-2 are isometric and reverse isometric views of an example packaged switch 247d. Packaged switches 247s and 247d are examples that may conform to one or more aspects of the TO-247 packaging standard.

[0032] (case) Packaged switches and packaged half-bridges can have cases. Figures 2a-1 and 2a-2 show a packaged switch 200 with an example case 202. Figures 2b-1 and 2b-2 show a packaged half-bridge 250 with an example case 252. Figures 2c-1 and 2c-2 show a packaged switch 211 with an example case 238. Figures 2d-1 and 2d-2 show a packaged switch 247s with an example case 248s. Figures 2e-1 and 2e-2 show a packaged switch 247d with an example case 248d.

[0033] The case insulates, protects and / or supports the switch module components, such as the power stack. The case can be made of glass, plastic, ceramic, etc. For ease of explanation, the case is assumed to be made of plastic, such as a molding compound, such as an epoxy resin. Modern molding compounds have evolved into complex formulations containing as many as 20 different ingredients. Fillers, such as alumina, can be added to increase the thermal conductivity of the molding compound, which can then aid in cooling the switch module components, including the power stack or gate drivers. The case can be formed using any one of many different types of packaging techniques, including transfer molding.

[0034] The packaged switches and packaged half-bridges can have small form factors. For example, the case of packaged switch 200 or packaged switch 211 can be sized 25×25×6 mm, the case of packaged switches 247s and 247d can be sized 16×21×5 mm, and the case of packaged half-bridge 250 can be sized 25×25×12 mm. The size (e.g., 25×25×6 mm) and shape (e.g., cubic) of the case of many packaged switches of the present disclosure can be substantially similar. Similarly, the size (e.g., 25×25×12 mm) and shape (e.g., cubic) of the case of many packaged half-bridges of the present disclosure can also be substantially similar. Figures 2a-1 to 2e-2 show a substantially cubic shaped case. Shapes other than those shown in the figures can be achieved by transfer molding. The exterior surface of the example case is substantially flat in most embodiments. The size or shape of the packaged switches or packaged half-bridges are not limited to those shown or described in this disclosure.

[0035] (Switch module) Traces and Leads The switch module includes traces and / or leads. Traces and leads are lengths of metal conductors that electrically connect two points. Traces have flat surfaces and are typically formed on a rigid printed circuit board (PCB), flexible PCB, direct bond copper (DBC) board, or the like. Leads are generally thicker than traces. Leads may be attached (e.g., soldered) to traces, die clips, die substrates, or the like. Leads may be cylindrical "pins" or may have a square or rectangular cross section. For purposes of illustration, leads have a square or rectangular cross section. Leads may be machined from a thin metal sheet.

[0036] DBC substrates can consist of ceramic tiles (commonly alumina) with copper sheets bonded to both sides by a high temperature oxidation process (the copper and substrate can be heated to a carefully controlled temperature in a nitrogen atmosphere containing about 30 ppm oxygen, under which a copper-oxygen eutectic forms, successfully bonding both the copper and the oxide used as the substrate). The top copper layer can be preformed before firing or chemically etched using PCB techniques to form traces, while the bottom copper layer is usually left plain. DBCs can have thermal advantages over rigid PCBs when utilized in switch modules. For example, heat generated by a switch controller can be dissipated through the DBC on which the controller is mounted.

[0037] The PCB has flat conductive traces that may be etched from one or more thin sheet layers of metal laminated on and / or between sheet layers of a non-conductive substrate. Metal vias extending through the non-conductive substrate layers may electrically connect traces at different levels. The switch module may include a rigid PCB, although it is understood that the switch module may be manufactured with a DBC substrate or other similar device. Although not shown in Figures 2a-1-2e-2, the packaged switches 200 and 211 and the packaged half-bridge 250 include one or more rigid PCBs on which the switch module components are mounted, although it is understood that DBCs may be used in alternative embodiments. The packaged switches 247s and 247d are devoid of a PCB or DBC substrate.

[0038] The traces of the PCB may carry signals (e.g., PWM signals, gate control signals, serial peripheral interface (SPI) signals, etc.) or voltages (e.g., DC power voltages). For example, the traces of the PCB may carry signals or voltages in electrical connections between internal components of the switch module (e.g., between a switch controller and a switch) or between an internal component (e.g., a switch controller) and a component external to the switch module (e.g., a microcontroller).

[0039] The leads may carry signals or power voltages. Each of the exemplary packaged switches and packaged half-bridges shown in FIGS. 2a-1, 2b-1, and 2c-1 has at least one set of “connector-leads” (e.g., connector-leads 204 and 206) that have ends attached (e.g., soldered) to respective traces of a rigid PCB or DBC (not shown). These connector-leads extend laterally from the cases 202, 252, and 238 as shown. These connector-leads may be part of a “connector” that is external to the packaged switch or packaged half-bridge. The connector may be attached to an external PCB that may include a microcontroller, gate drivers, and / or other components. Each of the exemplary packaged switches shown in FIGS. 2d-1 and 2e-1 has a set of three connector-leads 288. These connector-leads extend laterally from the cases 248s and 248d as shown. These connector-leads may be part of a connector that is external to the packaged switch. The connector can then be attached to an external PCB, which may contain gate drivers, voltage regulators and / or other components.

[0040] The connector-leads can carry current, signals or voltages in electrical connections between components internal to the switch module and components external to the switch module. For example, the connector-lead 204 in FIG. 2a-2 can carry a low-power PWM signal in electrical connections between a microcontroller on the control PCB and a component (e.g., a switch controller) internal to the packaged switch 200, while the connector-lead 206 can carry a power supply voltage in electrical connections between a power management integrated circuit (PMIC) on the control PCB and the same or different components internal to the packaged switch 200. The packaged half-bridge 250 (FIGS. 2b-1-2b-3) has similar connector-leads 204L, 204H, 206L and 206H. FIGS. 2d-1 and 2e-1 show connector-leads 288g, 288s and 288d. Although not shown in Figures 2d-1 and 2e-1, connector-leads 288g, 288s, and 288d are electrically connected to one or more gates, one or more first current terminals, and one or more second current terminals of switches within packaged switches 247s and 247d, respectively. Connector-leads 288d and 288s can carry significant current (e.g., 400A). Connector-leads 288 are coplanar in Figures 2d-1 and 2e-1. In alternative embodiments, one or more connector-leads 288 can be included in different planes.

[0041] Packaged switches and packaged half-bridges may include additional leads or conductors (e.g., bond wires) that carry signals (e.g., gate control signals) or voltages in the connections between the components of the switch module (e.g., the gate driver and the switch). For example, the switch module may include flex leads that carry gate signals in the connections between the gate driver and the switch. In another embodiment, a flexible PCB may be used to carry the gate signals in the connections between the gate driver and the switch.

[0042] (Power Stack) The switch module includes power stacks, each of which includes a switch mounted between a first metal conductor, called the die substrate, and a second metal conductor, called the die clip. The die substrate and die clip are described in more detail below. For ease of explanation, the switch module includes only one power stack.

[0043] A switch includes one or more power transistors (e.g., IGBTs, metal oxide field effect transistors (MOSFETs), etc.). A power transistor has two current terminals (such as collector and emitter for an IGBT, source and drain for a MOSFET) between which current flows when the transistor is activated, and a control or gate terminal. In one embodiment, multiple power transistors in a switch may be connected in parallel and controlled by a common signal at their gates, or in another embodiment, the gates of parallel connected power transistors in a switch may be controlled by independent signals.

[0044] In one embodiment of the present disclosure, the power transistor or power diode is a vertical structure semiconductor die. These power transistor dies have a trench-like structure with a first substantially flat current terminal (e.g., drain or emitter) on the bottom surface of the die, and a second substantially flat current terminal (e.g., source or collector) and a substantially flat gate terminal on the top surface of the die. The top and bottom surfaces face in opposite directions. The cathode and anode of the vertical structure power diode can be similarly configured on the opposing top and bottom surfaces of the die.

[0045] The switch can carry high levels of current without failure, depending on the size (e.g., gate width and length), type (e.g., MOSFET), semiconductor material (e.g., GaN) and number (e.g., six) of power transistors in the switch. The power transistors can carry high levels of current at high switching speeds (e.g., up to 100 kHz for Si IGBTs, up to 500 kHz for SiC MOSFETs, up to 1.0 GHz for GaN MOSFETs, etc.). When thermally connected and cooled by a heat sink or a bus bar that also acts as a heat sink, the power transistors can carry more current at higher switching speeds without failure.

[0046] (Die Substrate and Die Clip) The switches are sandwiched between a die substrate and a die clip. A first current terminal (e.g., collector or drain) and a second current terminal (e.g., emitter or source) of each switch transistor are connected (e.g., sintered, soldered, brazed, etc.) to the die substrate and the die clip, respectively. A gate of each transistor of the switch can be controlled by a signal from a switch controller. The signal can be transmitted to the gate by an electrical connection including a wire, ribbon, lead, trace, etc., or a series-connected combination thereof.

[0047] The die substrate or die clip can be machined or stamped from a sheet of layered or composite material having high thermal conductivity and low electrical resistance. The sheet can be made of alternating layers of copper (Cu) and molybdenum (Mo). For example, a layer of molybdenum can be sandwiched between layers of copper. The outer layers of copper have high thermal conductivity and the property of spreading heat efficiently. The molybdenum layer inserted between the copper layers can improve the thermal expansion coefficient of the sheet. The sheet can also include a layer of nickel formed on the outer layer (e.g., the outer layer of copper). In addition, an additional (e.g., bright silver or dull (i.e., matte) silver) layer can be formed (e.g., plated) on the outer layer of nickel. A device such as a switch can be attached (e.g., sintered) to the surface of the layer containing the additional (e.g., matte silver) material. For example, the switch can be sintered to the sheet of layered or composite material using, for example, a silver sintering paste. The thickness of the exemplary interleaved thin flat layers of molybdenum and copper can be selected to enhance the electrical, thermal and / or mechanical connection between the devices when attached (e.g., sintered). Also, sheets of composite materials with varying electrical, thermal and thermal expansion coefficients (mixtures of copper and molybdenum, copper and tungsten, copper and diamond, etc.) can be used to form the die substrate or die clip. The die substrate or die clip can be formed by joining (e.g., sintering, soldering, brazing, etc.) two electrically and thermally conductive workpieces. In yet another embodiment, the die substrate or die clip can be formed using 3D printing of metal or composite materials. The die substrate and die clip of the present disclosure should be devoid of dielectric elements.

[0048] The die substrate and die clip have terminals or pads through which electrical current and / or heat can be transferred. The die substrate has at least one terminal through which significant heat and electrical current can be transferred into and out of the packaged switch or packaged half-bridge. The die substrate may have one or more side terminals through which significant electrical current can be transferred into and out of the packaged switch or packaged half-bridge. These side terminals may also transfer heat from the packaged switch or packaged half-bridge, but their primary purpose is to carry electrical current.

[0049] The die clip has at least one terminal through which a significant current can be carried. In most cases, the current is transferred to the packaged switch or packaged half-bridge through this die clip terminal. The die clip may have additional terminals through which significant heat can be transferred from the packaged switch. In yet other embodiments, the die clip may have a similar structure to the die substrate and may include terminals through which significant heat and current can be transferred in and out of the packaged switch.

[0050] The die substrate terminals, die substrate side terminals, and die clip terminals may have substantially flat surfaces that are substantially flush or coplanar with the case surface of the packaged switch or packaged half bridge in which they are included. In other embodiments, the die substrate terminals, die substrate side terminals, and die clip terminals may have flat surfaces that are parallel to and recessed below the case surface, or may be parallel to and protrude above the case surface. Some die clip terminals may not be exposed through the case of the packaged half bridge. Some die substrate or die clip terminals may take the form of connector leads (e.g., connector lead 288d in FIG. 2d-1) that extend perpendicularly from the case surface of the packaged switch or packaged half bridge.

[0051] 2a-1 through 2e-2 illustrate exemplary die substrate terminals 230 that are capable of conducting significant heat and current into and out of the packaged switch or packaged half-bridge in which they are included.

[0052] 2a-1, 2a-2, 2b-1, 2b-2, 2c-1, and 2c-2 show example die clip terminals 232 that can transfer significant current into and out of the packaged switch or packaged half-bridge in which they are included. FIG. 2d-1 shows example die clip terminals (connector leads 288d) that can transfer significant current to and from the packaged switch 247s. FIG. 2c-2 and 2e-2 show example die clip terminals 344 that can transfer significant heat and / or current from the packaged switch in which they are included.

[0053] 2a-1, 2b-1, and 2c-1 show an exemplary die substrate side terminal 240. In some embodiments, a metal strap electrically connects the die substrate of one power stack to the die clip of another power stack. FIG. 2b-3 shows an exemplary metal strap 242 electrically connecting the high side die clip terminal 232H to the low side die substrate side terminal 240L. FIG. 2b-3 shows that the metal strap 242 is external to the packaged half bridge 250. In another embodiment, the metal strap 242 can be internal to the packaged half bridge.

[0054] The sizes and shapes of the die substrate terminals, die substrate side terminals, metal straps and die clip terminals should not be limited to those shown in the figures, i.e., the metal straps and terminals can take different forms, shapes and sizes.

[0055] 2a-1, 2c-1, 2d-1 and 2e-1 show die substrate terminals 230 having a rectangular substantially flat surface that is substantially flush with the substantially flat case surface of each of the packaged switches 200, 211, 247s and 247d. Also, FIGS. 2a-1 and 2c-1 show die substrate side terminals 240 having a substantially flat surface that is substantially flush with the substantially flat case surface of each of the packaged switches 200 and 211. FIGS. 2a-1 and 2c-1 show die clip terminals 232 having a rectangular substantially flat surface that is substantially flush with the substantially flat case surface of each of the packaged switches 200 and 211. The rectangular substantially flat die clip terminals 232 of the packaged switches of FIGS. 2a-1 and 2c-1 can be replaced with connector leads having a rectangular cross section extending from their backside. The packaged switches 211 and 247d have die clip terminals 344 having a rectangular, substantially flat surface that is substantially flush with the substantially flat bottom case surface, as shown in Figures 2c-2 and 2e-2. Figures 2d-1 and 2e-1 show die clip terminals 288d in the form of connector leads having a rectangular shaped cross section that extend laterally from the case of the packaged switches 247s and 247d.

[0056] 2b-1, 2b-2, and 2b-3 show die substrate terminals 230L and 230H with a rectangular substantially flat surface that is substantially flush with the substantially flat case surface of the packaged half bridge 250. FIGs. 2b-1, 2b-2, and 2b-3 show die clip terminals 232L and 232H with a rectangular substantially flat case that is substantially flush with the substantially flat surface of the packaged half bridge 250. In another embodiment, the rectangular substantially flat die clip terminals 232L and 232H can be replaced with connector leads with a rectangular cross section that extend from the back surface of the packaged half bridge 250 of FIGs. 2b-1, 2b-2, and 2b-3. Or, the rectangular substantially flat die clip terminals 232L of the packaged half bridge of FIG. 2b-2 can be replaced with connector leads with a rectangular cross section that extend from its back surface. 2b-1 to 2b-3 show the die substrate side terminal 240H of the higher-side die substrate and the die substrate side terminal 240L of the lower-side die substrate, both of which have substantially flat surfaces that are substantially flush with the substantially flat case surface of the packaged half-bridge 250.

[0057] In alternative embodiments, the planar surfaces of the die substrate terminals 230, die clip terminals 232, die clip terminals 344 and / or die substrate side terminals 240 can lie in a plane that is parallel to, above or below a plane that contains a substantially planar surface of a case, such as case 202, 211, or 250.

[0058] In some embodiments, current can enter the packaged switch or packaged half-bridge through a die substrate terminal and then exit through a die clip terminal, or current can flow through the packaged switch or packaged half-bridge in the reverse direction. By way of example, current can enter the packaged switch 200, 211, or 247 through the die substrate terminal 230 of the die substrate, flow through the die substrate, the activation switch, the die clip, and then exit the packaged switch 200, 211, or 247 via the die clip terminal 232, 288d, or 344 of the die clip, or current can flow in the reverse direction. Current can enter the packaged switch through a die substrate side terminal of the die substrate and then exit the packaged switch through a die substrate terminal of the same die substrate, or current can flow in the reverse direction through the packaged switch. For example, current can enter the packaged switch 200 or 211 through the die substrate side terminal 240 of the die substrate, flow through the die substrate, and then exit the packaged switch 200 or 211 through the die substrate terminal 230 of the die substrate, or the current can flow in the reverse direction.

[0059] Current can enter the packaged half bridge 250 of FIG. 2b-1 through the high side die substrate terminal 230H of the high side die substrate, flow through the high side die substrate, the active high side switch, the high side die clip, and exit the packaged half bridge 250 through the high side die clip terminal 232H of the high side die clip, or the current can flow in the reverse direction. Current can enter the packaged half bridge 250 of FIG. 2b-2 through the low side die substrate terminal 230L of the low side die substrate, flow through the low side die substrate, the active low side switch, the low side die clip, and then exit the packaged half bridge 250 through the low side die clip terminal 232L of the low side die clip, or the current can flow in the reverse direction. FIG. 2b-3 shows the metal strap 242. Current can flow into the packaged half-bridge 250 of FIG. 2b-3 via the high-side die substrate terminal 230H of the high-side die substrate, pass through the high-side die substrate, the activated high-side switch, the high-side die clip, the high-side die clip terminal 232H of the high-side die clip, the metal strap 242 electrically connecting the high-side die clip terminal 232H to one or more low-side die substrate terminals 240L of the low-side die substrate, one or more low-side die substrate terminals 240L, the low-side die substrate, and then flow out of the packaged half-bridge through the low-side die substrate terminal 230L of the low-side die substrate, or the current can flow in the opposite direction.

[0060] The die clip terminals, or die substrate terminals, may include two or more recesses that can mate with similarly shaped extensions of an external device (e.g., metal straps, phase bus bars, V+ bus bars, V- bus bars, etc., all of which are described in more detail below) to facilitate better electrical, thermal and / or mechanical connections therebetween.

[0061] The die substrate and die clip can transfer significant current and heat to and from the connected switches. The die substrate terminals, die substrate side terminals, and die clip terminals can transfer significant current and / or heat into and out of the packaged switch or packaged half bridge. For example, the die substrate can have a die substrate terminal 230 that is 24 mm wide and 11.2 mm long, which is connected to a device external to the packaged switch or packaged half bridge, such as a V+ bus bar. The die substrate can transfer currents of 400 A or more between the connected switches and the external device. The die clip can have a die clip terminal 232 that is 6 mm wide and 11 mm long, which is connected to a device external to the packaged switch or packaged half bridge, such as a V- bus bar. The die clip can transfer currents of 400 A or more between the connected switches and the external device. Metal straps (e.g., metal straps 242) can transfer currents of 400 A or more when connected between the die clip and the die substrate. The die clip terminals 288d are capable of carrying over 400A of current into and out of the packaged switch.

[0062] The switch can get hot due to conduction and switching losses, especially when carrying high currents at high switching speeds. Depending on its dimensions, the die substrate can conduct a large amount of heat from the packaged switch or packaged half-bridge through its die substrate terminals. For example, a die substrate terminal 230 that is 24 mm wide and 11.2 mm long can conduct heat from 0 W to 750 W or more. In other words, the die substrate terminal 230 can transfer 10, 20, 50, 100, 300, 750 W or more power. The die substrate can be thick (e.g., 0.1 mm to 6.0 mm thick, as measured between the die substrate terminal and its attached switch), and the thicker the die substrate, the more thermal capacitance it provides, which can be important in absorbing sudden increases in heat generated by the attached switch. The die substrate can transfer even more heat from the packaged switch or packaged half-bridge if its terminals are thermally connected to a heat sink or a bus bar that also functions as a heat sink.

[0063] Like the die substrate, the die clip can be thick (e.g., 0.1 mm to 8.0 mm thick, measured between the surface attached to the switch and the opposing surface), with the thicker die clip providing more thermal capacitance. In one embodiment described above, the die clip can have a first terminal for transferring current into and out of the packaged switch and a second terminal for transferring heat and / or current into and out of the packaged switch. The packaged switch 211 of Figures 2c-1 and 2c-2 has a die clip terminal 232 for transferring current into and out of the packaged switch and a second terminal 344 for transferring heat and / or current into and out of the packaged switch. The packaged switch 247d of Figures 2e-1 and 2e-2 has a die clip terminal 344 for transferring substantial current and heat into and out of the packaged switch. For lengths and widths such as the length and width of the die substrate terminal 230, the die clip terminal 344 of the packaged switches 211 and 247d can transfer heat from zero to 750 W or more. In other words, the die clip terminal 344 can transfer power from 10, 20, 50, 100, 300, 750 W or more. The die clip terminal 344 can transfer even more heat from the packaged switch if it is thermally connected to a heat sink or a bus bar that also functions as a heat sink. In another embodiment described above, the die clip can have a single terminal for transferring high levels of heat (e.g., 10, 20, 50, 100, 300 to 750 W or more) and current (e.g., 400 A or more). The single terminal can transfer even more heat from the packaged switch if the terminal is thermally connected to a heat sink or a bus bar that also functions as a heat sink.

[0064] Returning to FIG. 1a and FIG. 1c, conventional inverters or rectifiers use one or more bond wires to carry current in and out of the current terminals of the IGBT. These bond wires are prone to failure when they undergo rapid and extensive temperature cycling. The failure can be due to relatively high current density and low heat capacity in the wire itself or in the bond connection between the wire and the current terminal. The wire or bond connection often cracks or breaks during temperature cycling. Lift-off of the bond wire can also occur. In contrast, die clips and die substrates have low current density and high heat capacity. The current density is lower at the connection (e.g., sintered connection) between the switch terminals and the die clip or die substrate. As a result, failure is less likely to occur. Die substrates and die clips offer additional advantages over bond wires, such as lower parasitic parameters, as described below. Low parasitic parameters can improve the operating behavior of packaged switches and packaged half-bridges.

[0065] In general, pairs of components may be mechanically, electrically, and / or thermally connected, attached, bonded, etc. The connection, attachment, or bonding may transfer heat, electrical current, or both between the components. The connection, attachment, or bonding between pairs of components may be direct, such that surfaces of the components contact one another. Direct contact may be achieved by pressing the components together (i.e., "press fit") using mechanical structures such as clamps or bolts, or the connection, attachment, or bonding between pairs of components may be indirect, such as through an electrically conductive and / or thermally conductive material (e.g., solder, silver, conductive adhesive, thermal interface material (TIM), etc.), one or more additional components (die substrate, die clip, wire, ribbon, leads, traces, etc.), or a combination of one or more additional components with an electrically conductive and / or thermally conductive bonding material, etc.

[0066] Materials, such as solders, that connect, attach, or join components may expand at different rates when heated compared to the expansion rate of the components themselves. When the components and materials are heated, the different expansion rates can cause cracks to form in the materials that connect, attach, or join the components. The cracks can adversely affect the thermal and / or electrical conductivity of the connection, attachment, or joint between the components. Ideally, the coefficient of thermal expansion (CTE) of, for example, sintered bodies, conductive adhesives, solders, etc. that connect, attach, or join the components should be as close as possible to the CTE of the components to reduce the likelihood of crack or other defect growth.

[0067] Exemplary Packaged Switch (Package-type switches 200 and 201) With continued reference to Figures 2a-1 and 2a-2, Figures 3a-1-3a-3 are semi-schematic views of a packaged switch 200 that includes an exemplary switch module 300. The packaged switch 200 is shown in Figures 3a-1-3 with a transparent casing 202 to allow for a better understanding of the switch module components, their interactions, and their relative positions.

[0068] 3a-1, 3a-2 and 3a-3 show the relative positions of the switch module components when viewed from the top, side and back, respectively, of the packaged switch 200. The switch module 300 includes a rigid PCB to which the components can be mounted and electrically connected.

[0069] The connector leads (e.g., 204 and 206) may be attached to traces on the rigid PCB of the switch module before or after the switch module is encased in plastic in a transfer molding process or other process. The connector leads shown in Figures 2a-1 through 2c-2 are attached to traces on the rigid PCB before the formation of the plastic cases 202, 252, and 238. In other embodiments, some of the traces on the front of the rigid PCB may be shielded during the transfer molding process. The connector leads may then be attached to traces on the front of the rigid PCB after the molding process. For ease of explanation, the connector leads are considered to be part of the switch module to which they are attached.

[0070] The switch module 300 of FIG. 3a-1 includes an exemplary set of connector leads 314. More specifically, the set 314 includes eleven connector leads, including connector leads 204 and 206, which can be used to transmit signals and voltages between the switch module components and components external to the switch module, such as a microcontroller or PMIC. In the illustrated embodiment, the connector leads in the set 314 are coplanar, but it is understood that the disclosure should not be limited in this respect. The number of connector leads in the set 314 should not be limited to eleven. Fewer or more than two connector leads can be utilized depending on the design of the switch module.

[0071] The switch module 300 includes a switch controller 302 that controls a switch 304 based on a low power PWM signal received from a microcontroller or similar processor-based device via connector lead 204. The switch 304 is electrically and thermally connected to and disposed between a die substrate 312 and a die clip 316 (all symbolized in FIG. 3a-1, 3a-2, or 3a-3). The die substrate or die clip can carry large currents (e.g., 400A or more) in and out of a packaged switch or packaged half-bridge.

[0072] The switch 304 generates heat. The die substrate and die clip can transfer the heat away from the packaged switch or packaged half-bridge. The die substrate 312 is depicted in bold in the figures including FIG. 3a-2 and FIG. 3a-3 to indicate that it is configured to transfer more heat out of the packaged switch or packaged half-bridge and then to the die clip 316.

[0073] The switch module 300 includes a temperature sensor circuit, T_Sense, for sensing a temperature proximate the switch 304, a current sensor circuit, I_Sense, for sensing a current conducted by the switch 304, and a voltage sensor circuit, V_Sense, for sensing a voltage across the switch 304. The switch module may include fewer or more components than shown in the figures of this disclosure. For example, the switch module may include a voltage regulator that provides a supply voltage to one or more of the sensor circuits, T_Sense, I_Sense, and V_Sense.

[0074] 3a-1, 3a-2 and 3a-3 show the relative positioning of the components of the switch module with respect to each other. The switch controller 302 is located near the front F of the packaged switch 200, as seen in FIG. 3a-2, and the power stack consisting of the switch 304, die substrate 312 and die clip 316 is located near the back Bk of the packaged switch 200. The die substrate 312, switch 304 and die clip 316 are stacked vertically between a top T and a bottom B, as seen in FIG. 3a-2 and FIG. 3a-3. In a sense, stacking the first and second components means that the first and second components are included in first and second planes, respectively, that are spaced apart but parallel to each other. The first component in the first plane can be directly above the second component in the second plane, or the first component can be laterally offset in the first plane such that the second component is not directly below the first component.

[0075] For ease of illustration and understanding, the die substrate terminals 230 are depicted as squares in most of the figures. In some figures, the die clip terminals 232 are depicted as hexagons or octagons. In the top and rear views of Figures 3a-1 and 3a-3, respectively, the die clip terminals 232 are depicted as hexagons. In the side view of Figure 3a-2, the die clip terminals 232 are depicted as octagons. The same die substrate terminal and die clip terminal designations are used in the other figures.

[0076] The die substrate terminal 230 is shown positioned to be flush with the top surface of the packaged switch 200 in Figures 3a-2 and 3a-3, and the die clip terminal 232 is shown positioned to be flush with the left side surface of the packaged switch 200 in Figures 3a-1 and 3a-3. The die clip terminal 232 is depicted as a center dot in Figure 3a-2, indicating that current enters and exits the packaged switch 200 through its left side surface.

[0077] 3b-1, 3b-2 and 3b-3 show relevant components of another packaged switch 201 similar to the packaged switch 200, but arranged to show that the die clip terminal 232 is flush with the right side. The die clip terminal 232 in FIG. 3b-2 is drawn without a central dot to show that the current enters and exits from the right side of the packaged switch 201. Note again that the die substrate terminal or die clip terminal can include a flat surface that is recessed below the packaged or packaged half-bridge case surface in other embodiments, or the die substrate terminal or die clip terminal can include a flat surface that protrudes above the packaged or packaged half-bridge case surface.

[0078] Example Switch Controller 302 3A-4 are schematic diagrams illustrating components of an exemplary switch controller 302 that can be utilized in most switch modules of the present disclosure. The switch controller 302 includes a gate driver 306, resistors R1 and R2, and diodes 308 and 310. The components of the switch controller can be electrically connected to traces on a rigid PCB. For example, the PCB traces can be part of an electrical path that provides a voltage difference (e.g., Vdrain-Vsource, or Vcollector-Vemitter) across the current terminals of the switch 304 to the gate driver 306. This voltage difference can be used by the gate driver 306 to monitor the switch 304 for fault conditions. The switch controller can include fewer or more components than those shown in FIG. 3a-4.

[0079] 3a-4 show switch 304, but not the die substrate and die clip between which switch 304 is sandwiched. Diode 308 is electrically connected between the die substrate and gate driver 306, which is electrically connected to the die clip, and the output of gate driver 306, Vg, is electrically connected to the gate of switch 304 through resistors R1 and R2.

[0080] Conventional inverter and rectifier gate drivers, such as gate drivers H101-H103 and L101-L103 in Figs. 1a and 1c, are mounted on a control PCB and located remotely from the power transistors (e.g., IGBT THx) they control. Long signal paths carry the gate control signal Vg from the gate drivers on the control PCB to each power transistor. These long signal paths have large parasitic parameters (e.g., resistance, inductance, and / or capacitance), which can result in increased switching losses, power consumption, signal delays, and / or reduced switching speed. Also, signals transmitted over long signal paths are susceptible to noise. In contrast, the switch controller 302 (Figs. 3a-4), which includes the gate driver 306, is contained within a packaged switch (or packaged half-bridge) and located close to the switch 304. The signal path SP0, which can be 10 mm or less, connects the control signal output of the gate driver 306 to the gate of the switch 304. For example, the signal path SPO may be 9, 7, 5, 3 mm or less. A shorter signal path reduces parasitic resistance, parasitic inductance, parasitic capacitance, signal delay, signal degradation due to noise, and / or other issues associated with the gate driver implemented on the control PCB described above. Because the gate driver 306 is close to the switch 304, the rise and fall time of Vg at the gate may be shorter. The gate driver 306 may consume less power while driving the gate of the switch 304, and the gate driver 306 may drive the gate more quickly. Because the gate driver 306 is closer to the switch 304, the speed at which the switch 304 is switched may be faster when compared to the speed of a switch driven by a gate driver located remotely on the control PCB.

[0081] (Example Switch 304) Generally, the switch includes one or more power transistors, such as IGBTs, MOSFETs, JFETs, BJTs, etc. The switch may include additional components, such as diodes. The transistors and / or additional components of the switch 304 may be made from any one of many different types of semiconductor materials, such as Si, SiC, GaN, GaO, cubic boron arsenide, etc. The power transistors in the switch 304 may be of different types. For example, the switch 304 may include one or more SiC MOSFETs and one or more GaN MOSFETs, all connected in parallel, or the switch 304 may include one or more MOSFETs and one or more IGBTs, all connected in parallel.

[0082] 3a-5 and 3a-6 are schematic diagrams of an exemplary switch 304 that can be utilized in the switch module of the present disclosure. In FIG. 3a-5, the switch 304 includes a power IGBT connected in parallel with a power diode D. The collector c and the diode cathode are attached to a die substrate (e.g., die substrate 312) using any one of many different bonding techniques (e.g., sintering, soldering, transient liquid phase bonding, conductive adhesive processes, etc.), and the emitter e and the diode anode are attached to a die clip (e.g., die clip 316) using any one of many different bonding techniques. The IGBT has one emitter but can have multiple substantially planar emitter terminals or pads. Each of the emitter terminals or pads can be attached to a corresponding planar surface of the die clip. The IGBT has one collector but can have multiple substantially planar collector terminals or pads. Each of the collector terminals or pads can be attached to a corresponding planar surface of the die substrate.

[0083] In FIG. 3A-6, the switch 304 includes power MOSFETs (e.g., SiC MOSFETs, GaN MOSFETs, or MOSFETs made of other materials such as GaO) N1 and N2 coupled in parallel. The drains d of the MOSFETs N1 and N2 are attached (e.g., sintered, soldered, transient liquid phase bonding, conductive adhesive process, etc.) to a die substrate (e.g., die substrate 312) and the sources s are attached (e.g., sintered, soldered, transient liquid phase bonding, etc.) to a die clip (e.g., die clip 316). The MOSFET has one source, but may have multiple substantially planar source terminals or pads, each of which may be attached to a corresponding planar surface of the die clip. The MOSFET has one drain, but may have multiple substantially planar drain terminals or pads. Each of the drain terminals may be attached to a corresponding planar surface of the die substrate. Each gate g of the switch 304 is controlled by a high-current gate control signal Vg from a gate driver 306.

[0084] 3a-4-3a-6, the gate driver 306, in one embodiment, controls one or more transistors of the switch 304 based on a PWM signal received from a microcontroller. The gate driver 306 activates one or more transistors via a gate voltage Vg when the PWM is asserted. In another embodiment, the gate driver 306 can take the form of a multi-transistor gate driver that can independently control separate transistors in the switch 304 based on the PWM signal. For example, in response to receiving the PWM signal, the multi-transistor gate driver can generate intentionally staggered gate control voltages V1g and V2g (not shown) that control the gates of transistors N1 and N2, respectively, of the switch 304 of FIG. 3A-6. In this example, the rising edge of V1g can lead the rising edge of V2g, and / or the falling edge of V1g can lead the falling edge of V2g, or; the rising edge of V1g can lead the rising edge of V2g, and / or the falling edge of V2g can lead the falling edge of V1g. V2g may be an intentionally delayed version of V1g, or vice versa. The delayed signal may be created by a device such as a buffer or a set of serially connected buffers, with V1g as the input and V2g as the output, or vice versa.

[0085] (Example Leads and Traces) Exemplary PCB traces are symbolically illustrated in the figures of this disclosure. Exemplary PCB traces electrically connect to components of the switch module. For example, in FIG. 3A-4, a PCB trace connects the gate driver 306 and resistor R1. Traces can also be used for electrical connections between components of the switch module (e.g., the gate driver 306) and components external to the packaged switch or packaged half-bridge (e.g., a microcontroller). Some components of the switch module can be connected via a series combination of leads, wires, traces, metal ribbons, or other conductors. For example, traces, bond wires, or flex leads of a flexible flat cable (i.e., flexible PCB) can be used to electrically connect resistor R2 and the gate g of the switch 304. Some PCB traces are not shown in FIG. 3a-1 for ease of illustration.

[0086] One or more of the individual switch module components (e.g., one or more of the gate driver 306, I_Sense, T_Sense, V_Sense, etc.) may take the form of a packaged device. The packaged device may have its own leads that are connected (e.g., soldered) to traces on the switch module PCB. For example, the gate driver 306 (FIGS. 3a-4) may take the form of a packaged semiconductor die. The packaged gate driver may have leads that are soldered to traces on the switch module PCB. The I_Sense, V_Sense, or T_Sense may also take the form of a packaged semiconductor die. These packaged devices may also have leads that are connected to traces on the switch module PCB. The resistors R1 and R2 and the diodes 308 and 310 may be packaged devices with leads that are connected to traces on the switch module PCB. Alternatively, one or more of the individual switch module components (e.g., one or more of the gate driver 306, I_Sense, T_Sense, V_Sense, etc.) may take the form of a bare semiconductor die (i.e., without a package) with pads that can be wire bonded to traces on the switch module PCB. In this disclosure, it is presumed that some switch module components (e.g., gate driver 306, I_Sense, T_Sense, and / or V_Sense) are formed of bare die that are mounted to the switch module PCB and have pads wire-bonded to traces on the switch module PCB, although it is understood that the disclosure should not be limited in this respect.

[0087] (Exemplary Die Substrate and Die Clip Terminals) The power stack is created by electrically and thermally connecting the switches between the die clip and the die substrate. The first current terminal (e.g., collector, drain, etc.) of each transistor in the switch can be sintered to the die substrate using a layer of highly conductive sintered material such as silver, copper or other material. There is no dielectric between the switch and the connected die substrate terminal. The second current terminal (e.g., emitter, source, etc.) of each transistor in the switch can be sintered to the die clip via a layer of highly conductive sintered material such as silver, copper or other material. There is no dielectric between the switch and the die clip terminal of the connected die clip. Thus, there is no dielectric between the die substrate terminal and the die clip terminal of the power stack.

[0088] The die substrate terminals are configured for direct or indirect electrical and / or thermal connection to the device. The die substrate terminals may be electrically and / or thermally connected to a heat sink, a bus bar, or a surface of a bus bar that also functions as a heat sink. For example, the die substrate terminals may be electrically and / or thermally connected to a "V+ bus bar" that is electrically connected to a V+ terminal of an inverter or rectifier system that may be electrically connected to a battery, fuel cell, DC / DC converter, etc. The die substrate terminals may be electrically and / or thermally connected to a "V- bus bar" that is electrically connected to a V- terminal of an inverter or rectifier system that may be electrically connected to a battery, fuel cell, DC / DC converter, etc. The die substrate terminals may be electrically and / or thermally connected to AC busbars, also called "phase busbars", which in turn are electrically connected to AC terminals of an inverter or rectifier system, which in turn may be connected to the terminals of a stator winding W of a motor, an inductor L of a filter, or other devices. Busbars are generally metal elements that carry large currents (e.g., 400A or more). The material composition (copper, aluminum, etc.) and cross-sectional size of the busbar or its elements determine the maximum amount of current that can be safely carried and its parasitic parameters. Busbars with larger cross-sectional areas can lower the parasitic parameters. Busbars can be in any of many different configurations depending on the design of the inverter or rectifier system in which they are used. Busbars may also be constructed as assemblies from multiple components.

[0089] The heat sink may have one or more channels, each of which may receive a heat pipe, as described more fully below. Bus bars may also function as heat sinks, and the heat sink may have one or more channels, each of which may receive a heat pipe, as described more fully below. A typical heat pipe consists of a sealed tube made of a metal, such as copper or aluminum. The inner and / or outer surface of the heat pipe may be formed with one or more thermally conductive dielectric layers. The dielectric on the outer surface electrically insulates the metallic heat pipe from the heat sink or bus bar in which it is received. In another embodiment, there is no dielectric between the metallic heat pipe and the heat sink or bus bar in which it is received. In this alternative embodiment, the outer surface of the metallic heat pipe is electrically and thermally connected to the heat sink or bus bar in which it is received. The heat pipe may also be formed of other thermally conductive materials.

[0090] In general, heat sinks or bus bars can be fabricated (e.g., extruded, 3D printed, etc.) in whole or in part from conductive metals such as copper or aluminum, and can have different shapes, sizes and dimensions (e.g., length, width, height, etc.) to accommodate different inverter or rectifier designs. Bus bars or heat sinks can be formed by attaching (e.g., soldering, sintering, etc.) two extruded metal halves together after placing a heat pipe, with or without an outer dielectric layer, between them. Prior to attachment, the heat pipes can be coated with a thin layer of thermal paste (also called thermal compound, thermal grease, thermal interface material (TIM), thermal gel, heat paste, heat sink compound, heat sink paste, or CPU grease) to eliminate any air gaps or spaces from the interface between the heat pipes and the resulting heat sink or bus bar. Heat sinks or bus bars can be formed by casting aluminum, copper, or other material around the heat pipes. Casting is the process of feeding liquid metal into a mold that contains a negative (i.e., a three-dimensional negative image) of the intended shape. The heat pipe, with or without a dielectric surface on its exterior, can be received in the mold before the liquid metal is dispensed. In yet another embodiment, the heat sink or bus bar on which the heat pipe with its dielectric layer is received is heated, causing the metal layer of the heat sink or bus bar to reflow and remove any air gaps or spaces at the interface between the heat pipe dielectric layer and the heat sink or bus bar. In other embodiments, a thin layer can be formed on the dielectric layer of the metal heat pipe to make it easier to thermally connect to the bus bar or heat sink.

[0091] The heat sink or bus bar that also functions as a heat sink can include flat surfaces that can be press-fit, soldered, sintered, or otherwise connected to the die substrate terminals or die clip terminals to ensure electrical and thermal connection therebetween. A press-fit connection can reduce or eliminate problems associated with the CTE differences discussed above.

[0092] 2a-1 and 2c-1, the exemplary die substrate terminals 230 have rectangular flat surfaces exposed through the top surface of the case of the packaged switches 200 and 211. The packaged half-bridge 250 of FIGS. 2b-1-2b-3 has similar die substrate terminals 230H and 230L. The dimensions (e.g., width and length) of the exposed terminals 230 are configured to transfer significant current and heat. In one embodiment, the die substrate terminals 230 are parallel to but opposite (i.e., 180 degrees) at least one flat surface of the die substrate 312 (not shown) to which the first current terminal (e.g., collector, drain, etc.) is sintered. The die substrate can have small side terminals (e.g., side terminal 240 shown in FIG. 2b-1) that extend through the left or right side of the packaged switch or packaged half-bridge. Current can enter or exit the packaged switch or packaged half-bridge through these die substrate side terminals. A metal strap can electrically connect a side terminal of a die substrate of one packaged switch to a die clip terminal of another packaged switch. A metal side strap can electrically connect die clip terminals in a packaged half bridge, or a metal strap can electrically connect a side terminal of a die substrate of one switch module in a packaged half bridge to a die clip terminal of another switch module in the packaged half bridge. FIG. 2b-3 shows an exemplary metal strap 242 electrically connecting a side terminal 240L to a die clip terminal 232H of a packaged switch 250. The metal strap should be configured to carry a significant current (e.g., 400A or more) between components such as terminals 240L and 232H of FIG. 2b-3.

[0093] In addition to being connected to the die substrate, the switch 304 is electrically and / or thermally connected to a die clip having one or more die clip terminals. The die clip terminals can be configured to electrically and / or thermally connect directly or indirectly to a device external to the packaged switch or packaged half-bridge. The die clip terminals can be electrically and / or thermally connected to a heat sink, a bus bar, or a surface of a bus bar that also functions as a heat sink. The die clip terminals (e.g., die clip terminals 232 of the packaged switch 200) can be electrically and / or thermally connected to a V bus bar. The die clip terminals (e.g., die clip terminals 344 of the packaged switch 211 of FIG. 2c-2) can be electrically and / or thermally connected to a bus bar that also functions as a heat sink. The die clip terminals can be electrically and / or thermally connected to a phase bus bar. The die clip terminals can be electrically connected to a metal strap, such as the metal strap 242 shown in FIG. 2b-3.

[0094] 2a-1 and 2c-1, each of the exemplary die clip terminals 232 has a rectangular, substantially flat surface area exposed through the case of the packaged switch. The die clip terminals 232 can be electrically connected to metal straps that can be connected to side terminals of the die substrate. The packaged half bridge 250 of FIGS. 2b-1 and 2b-2 has similar die clip terminals 232H and 232L. The dimensions (e.g., width and length) of the exposed terminals 232 are configured to carry significant current. The die clips of the exemplary packaged switch 211 and packaged switch 247d of FIGS. 2c-2 and 2e-2, respectively, have additional flat surface terminals 344 through which heat can be transferred.

[0095] Exemplary Gate Driver 306 and Other Switch Module Components The gate driver of the switch module may receive a signal from a microcontroller or similar processor-based device. For example, the gate driver 306 of FIGS. 3A-4 may receive a low-power PWM driver control signal, such as one of the PWM signals described with reference to FIG. 1A. Additionally, the gate driver 306 may receive a low-power reset signal from the microcontroller or other device. After receiving an asserted reset signal, the gate driver 306 may activate the switch 304 in response to the assertion of a pulse-width modulated (PWM) signal it receives by asserting a high-current, gate control signal Vg. Ideally, the length of the signal path SP0 between the output of the gate driver 306 and the gate of the switch 304 should be as short as possible to mitigate adverse effects on the gate control signal Vg due to parasitic inductance, parasitic capacitance, noise, etc.

[0096] The gate driver can also send signals to a microcontroller or similar processor-based device. For example, the gate driver 306 can disable the switch 304 (i.e., keep the switch in a deactivated state) and assert a fault signal when a fault is detected, such as excessive current conduction through the switch 304 when it should be deactivated or an abnormally low voltage across the switch 304. The microcontroller or similar processor-based device can receive and process the fault signal. Other switch module components, such as an I_Sense circuit and a T_Sense circuit, can send signals representing the current through the switch 304 and the temperature in the vicinity of the switch 304 (e.g., within 1-10 mm), respectively. The signal output of the T_Sense can more accurately represent the temperature the closer the T_Sense is to the switch. A voltage sense circuit, V-Sense, if added, can similarly send a signal representing the voltage across the current terminals of the switch 304. The microcontroller or similar processor-based device can receive and process the signals provided by these components. For example, the microcontroller may compare the signal representative of temperature to a first threshold and, if the threshold is exceeded, alter the frequency or duty cycle of the PWM control signal provided to the gate driver 306, or the microcontroller may continuously deassert the PWM control signal provided to the gate driver 306 if the threshold is exceeded, thereby continuously deactivating the switch 304.

[0097] 3A-7 show an example gate driver 306 including a low voltage input stage 320 in data communication with a high voltage output stage 322 through a galvanic isolation circuit 324. Galvanic isolation is used when two or more circuits must communicate, but their grounds are at different potentials. Galvanic isolation circuits may use transformers, capacitors, optocouplers, or other devices to achieve isolation between the circuits. For ease of explanation, the galvanic isolation circuit 324 utilizes a transformer device to achieve galvanic isolation. The low voltage input stage 320 is coupled to receive a first power supply voltage VDDI and a first ground GI via respective PCB traces, and includes a logic circuit 330 that receives a PWM signal and a reset signal via respective PCB traces. The high voltage output stage 322 is coupled to receive a second power supply voltage VDDO+, a third power supply voltage VDDO−, and a second ground GO via respective PCB traces, and includes a logic circuit 332 that receives control signals from the logic circuit 330 via the galvanic isolation circuit 324. The high voltage output stage 322 also includes a buffer 340 that is controlled by the output signal from the logic circuit 332. The buffer 340 asserts Vg when the control signal output of the isolation circuit 324 is asserted. Other types of gate drivers 306 are contemplated.

[0098] I_Sense generates a voltage signal Vi with a magnitude proportional to a current flow, such as a current through the switch 304. I_Sense can include an induced current sensor that measures the magnetic field caused by the current flow through the switch 304 in general and the current flow through the die clip in particular. The induced current sensor is electrically isolated from the switch 304. An exemplary die clip 316 includes a horizontal portion and a vertical portion. The I_Sense circuit can measure the current flow through a constriction (not shown) of the horizontal portion of the die clip 316. I_Sense conditions the signal output of the induced current sensor for subsequent use by the microcontroller. T_Sense can include a thermistor that can generate a voltage signal Vt with a magnitude proportional to the temperature near the switch 304. A thermistor is a type of resistor whose resistance is temperature dependent, and the relationship between resistance and temperature is linear. T_Sense conditions the signal output of the thermistor for use by the microcontroller. The thermistor is electrically isolated from the switch 304. V_Sense can generate a voltage signal Vv that is proportional to the voltage across the current terminals of the switch.

[0099] The analog signals Vi, Vv, and Vt from the I_Sense, V_Sense, and T_Sense circuits, respectively, are transmitted to the microcontroller and converted to their digital equivalents. Connector leads on the front of the packaged switch or packaged half-bridge can be used to transmit signals including Vi, Vv, Vt, and fault signals between the respective switch module components on the switch module PCB and the microcontroller mounted on the control PCB. The connector leads can also be used to transmit other signals (e.g., PWM and reset) and voltages (e.g., VDDI, VDDO+, GI, etc.) between the control PCB and the packaged switch or packaged half-bridge.

[0100] A microcontroller on the control PCB board can process the digital equivalents of the received signals (e.g., Fault, Vi, Vv, and Vt) according to instructions stored in memory. The microcontroller can adjust the duty cycle and / or period of the driver control signal PWM based on the digital equivalents of Vi, Vv, Vt, and / or other signals.

[0101] (Package type switch 200D) A packaged switch may include a diode in addition to a switch. Figures 3A-8 and 3A-9 are semi-schematic diagrams of an exemplary packaged switch 200D, which includes a diode that may be electrically connected in series with the switch 304. The diode may be electrically connected in series with the switch via an external metal strap (not shown).

[0102] The packaged switch 200D is shown in Figures 3a-8 and 3a-9 with a transparent case to allow a better understanding of the components of the switch module, their interactions, and their relative positions. The dimensions of the packaged switch 200D can be substantially similar to the packaged half-bridge 250 shown in Figures 2b-1 to 2b-3.

[0103] The packaged switch 200D includes a switch module 300D that includes the components of the switch module 300 shown in FIG. 3a-1, and a diode stack having one or more diodes 269 attached (e.g., sintered) between the die clip 316L and the die substrate 312L.

[0104] 3A-8 and 3A-9 show the relative positions of the switch module components when viewing packaged switch 200D from the side and back, respectively. Switch module 300D includes connector leads (only connector lead 204 is shown in FIG. 3a-8) for transmitting signals and voltages between the switch module components and external components such as microcontrollers and PMICs. Switch module 300D includes switch controller 302 that controls switch 304 based on low power, PWM and / or other signals received from a microcontroller or similar processor-based device. Switch 304 is electrically and thermally connected to and disposed between die substrate 312H and die clip 316H, all of which are symbolically indicated.

[0105] 3A-9, the switch module 300D includes a temperature sensor circuit, T_Sense, for sensing the temperature proximate the switch 304, a current sensor circuit, I_Sense, for sensing the current conducted by the switch 304, and a voltage sensor circuit, V_Sense, for sensing the voltage across the switch 304. A switch module may include one or more components.

[0106] 3a-8 and 3a-9 show the relative positioning of the components of the switch module with respect to each other. The switch controller 302 is located near the front F and top of the packaged switch 200D, as seen in FIG. 3a-8. The power stack, consisting of the switch 304, the die substrate 312H, and the die clip 316H, is located near the top T and back Bk of the packaged switch 200D. The die substrate 312H, the switch 304, and the die clip 316H are stacked vertically between the top T and the bottom B, as seen in FIG. 3a-8 and 3a-9. The diode stack, consisting of the diode 269, the die clip 316L, and the die substrate 312L, is located near the bottom B and back Bk of the packaged switch 200D. The die substrate 312L, the diode 269, and the die clip 316L are stacked vertically between the top T and the bottom B, as seen in FIG. 3a-8 and 3a-9. The power stack and the diode stack may be mounted on opposite sides of a rigid PCB (not shown). The power stack, the diode stack and the rigid PCB may be stacked vertically between a top T and a bottom B.

[0107] The die substrate terminals 230H and 230L are positioned in a manner shown in Figures 3a-8 and 3a-9 to be flush with the top and bottom surfaces of the packaged switch 200D. The die clip terminals 232H and 232L are positioned in a manner shown in Figures 3a-8 and 3a-9 to be flush with the left side surface of the packaged switch 200D.

[0108] 3a-8 and 3a-9 show diode 269 electrically isolated from switch 304. Although not shown, metal straps for electrically connecting die clip terminals 232L and 232H can be added before or after the case of packaged switch module 200D is formed.

[0109] 3A-8 and 3A-9 show the anode of the diode 269 attached to the die clip 316L and the cathode attached to the die substrate 312L. In an alternative embodiment of the packaged switch 200D, the cathode of the diode 269 can be attached to the die clip 316L and the anode can be attached to the die substrate 312L.

[0110] (Package type switch 203) The packaged switches 200 and 201 allow for single-sided cooling of the switch 304. FIGS. 3c-1 and 3c-2 are semi-schematic diagrams showing relevant components of another packaged switch 203 that allows for double-sided cooling of the switch 304. The packaged switch 203 is similar in many respects to the packaged switch 200 and includes many of its components. The packaged switch 203 includes a switch module that includes a rigid PCB on which components can be mounted. The PCB can be C-shaped to allow for double-sided cooling of the switch 304. An exemplary C-shaped PCB is described later in this specification. The packaged switch 203 is shown in a transparent case to allow a better understanding of the components, their interactions, and their relative placement within the switch module.

[0111] 3c-1 and 3c-2 show the relative positions of components of the packaged switch 203 when viewed from the side and back, respectively. The packaged switch 203 includes a switch 304 controlled by a switch controller 302. The switch 304 is connected (e.g., sintered) to and disposed between a die substrate 312 and a die clip 342 that includes a die clip terminal 344. In other words, first and second current terminals of the switch 304 are attached to the die substrate 312 and the die clip 342, respectively.

[0112] The die substrate 312 and the die clip 342, including the die clip terminals 344, are symbolically depicted. Both the die substrate 312 and the die clip 342 are depicted in bold to indicate that they are configured to transfer substantial current and heat. The die substrate 312 and the die clip 342 may be similar with substantially similar terminals 230 and 344, respectively. The die clip 342 may require a pedestal (described in more detail below) to engage the emitter or drain terminals, or pads, of the switch 304. The height HDC of the die clip 342 may be greater than the height HDS of the die substrate 312 such that the die clip terminals 344 are substantially flush with the bottom surface of the packaged switch 203. The shape and form of the die clip 342 and its terminals 344 are substantially different from the die clip 316 and its terminals 232 (FIGS. 3b-2 and 3b-3).

[0113] 3c-1 and 3c-2 illustrate the relative positioning of certain components with respect to one another. The die substrate 312, switch 304, and die clip 342 are stacked vertically as shown between the top T and bottom B of the packaged switch 203. The switch controller 302 is located near the front F of the packaged switch 203, and the switch 304 is located near the back Bk. The die substrate terminals 230 are shown in a position shown to be flush with the top surface of the packaged switch 203, and the die clip terminals 344 are likewise shown to be flush with the bottom surface.

[0114] (Package type switch 205) 3d-1 and 3d-2 are semi-schematic diagrams showing relevant components of an exemplary packaged switch 205. The packaged switch 205, shown in a transparent case, is similar to the packaged switch 200 and includes many of its components. The packaged switch 205 can include a switch module, which includes a rigid PCB on which components can be mounted. FIGS. 3d-1 and 3d-2 show the relative positions of certain components of the packaged switch 205 from side and rear views, respectively. Similar to the packaged switch 200, the packaged switch 205 includes a switch 304 controlled by a switch controller 302. The switch 304 is connected (e.g., sintered) to and between a die substrate 312 and a die clip 346 that includes die clip terminals 232. More specifically, first and second current terminals of the switch 304 are connected to the die substrate 312 and the die clip 346, respectively. The die substrate 312, the die clip 346, and their terminals are symbolically shown. 3d-1 and 3d-2 show the relative positioning of certain components with respect to each other. The die substrate 312, the switch 304, and the die clip 346 are stacked vertically as shown between the top T and bottom B of the packaged switch 205. The switch controller 302 is located near the front F of the packaged switch 205, and the switch 304 is located near the back Bk. The die substrate terminals 230 are shown to be flush with the top surface of the packaged switch 205, and the die clip terminals 232 are shown to be flush with the back surface in FIG. 3d-1. In another embodiment, the die clip terminals 232 are replaced with leads extending laterally from the back surface Bk. In either case, the die clip 346 is shown with a thin wall to show that it is configured primarily to transmit current and not heat.

[0115] (Package type switch 211) With reference to Figures 2c-1 and 2c-2, Figures 3e-1 and 3e-2 are semi-schematic diagrams illustrating some components of an exemplary packaged switch 211. Figures 3e-1 and 3e-2 show the relative positions of the switch components when viewed from the side and back, respectively, of the packaged switch 211 shown in a transparent case. Similar to the packaged switch 203, the packaged switch 211 allows for double-sided cooling of the switch 304. The packaged switch 211 can include a switch module, which includes a rigid PCB on which the components can be mounted.

[0116] 3e-1 and 3e-2 show the relative positions of certain components of packaged switch 211 from side and back views, respectively. Similar to packaged switch 200, packaged switch 211 includes a switch 304 controlled by a switch controller 302. Switch 304 is connected (e.g., sintered) between a die substrate 312 and a die clip 345 that includes two die clip terminals 232 and 344. First and second current terminals of switch 304 are sintered to die substrate 312 and die clip 345, respectively.

[0117] The die clip 345 and its terminals 232 and 344 are symbolically depicted. The die clip 345 includes a first portion 348 and a second portion 350, and a third portion 354 extending perpendicularly to the first and second portions, as shown. The third portion 354 is depicted as thin to indicate that it is configured primarily to transmit electrical current, while the first portion 348 and the second portion 350 are depicted as thick to indicate that they are both configured to transmit substantial electrical current and heat. However, the second portion 350 will only transmit heat if connected to an electrically isolated device, such as an electrically isolated heat sink. FIG. 3e-2 shows a current sensor circuit I_Sense for sensing the current transmitted through the third portion 354.

[0118] 3e-1 and 3e-2 illustrate the relative positioning of certain components with respect to each other. The die substrate 312, the switch 304, and the die clip 345 are stacked vertically as shown between the top T and bottom B of the packaged switch 211. The switch controller 302 is located near the front F of the packaged switch 211. The switch 304 is located near the back Bk. The die substrate terminal 230 is located to be shown flush with the top surface of the packaged switch 211. The die clip terminal 232 is located in a position shown to be flush with the left side in FIG. 3e-2, and the die clip terminal 344 is located to be shown to be flush with the bottom surface. The height HDC of the die clip 345 can be greater than the height HDS of the die substrate 312 so that the die clip terminal 344 is substantially flush with the bottom surface of the packaged switch 211. In another embodiment, the die clip 345 is replaced with a die clip having terminals in the form of leads extending laterally from the back surface Bk.

[0119] (Package type switch 209) 3f-1 and 3f-2 are semi-schematic diagrams showing relevant components of another packaged switch 209. 3f-1 and 3f-2 show the relative positions of certain components of packaged switch 209 shown with a transparent case when viewed from the side and back, respectively. Packaged switches 211 and 209 are substantially similar. The positioning of the die clip terminals is one major difference between the two. As shown in FIG. 3f-2, the die clip terminals 232 of packaged switch 211 are in a position shown to be flush with the left side, while the die clip terminals 232 of packaged switch 209 are flush with the right side.

[0120] (Exemplary Switch Module) The switch module components in a packaged switch or packaged half-bridge (e.g., gate driver 306, resistor R1, diode 308, I_Sense circuit, T_Sense circuit, power stack, etc.) may be mounted on a rigid PCB and electrically connected by traces thereon. Packaged switch modules 200 and 211 are examples where the switch module is mounted on a rigid PCB. In other packaged switch modules, a rigid PCB is not utilized. Packaged switch modules 247s and 247d are examples where there is no rigid PCB. In some packaged half-bridges, the high-side and low-side switch module components are mounted on separate PCBs or on opposite sides of the same PCB.

[0121] The power stack (i.e., the switch sandwiched between the die substrate and die clip) may be supported on the switch module PCB using mechanical structures such as metal posts, pedestals, etc. The mechanical structures may provide space between the power stack and the PCB. In addition to providing support, the mechanical structures may electrically connect the die clip and / or the die substrate to respective traces on the PCB. For example, one end of the mechanical support structure may be attached (e.g., soldered) to the die substrate or die clip and the other end may be attached (e.g., soldered) to a trace or pad on the PCB.

[0122] After the power stack is connected to the PCB, the mechanical support structure can hold the power stack in place as the PCB with the power stack and mounted components is substantially covered with a liquid molding compound (e.g., liquid epoxy resin) using, for example, a transfer molding process. The liquid molding compound can flow into the space separating the die clip from the die substrate. After curing, the molding compound provides additional structural support to hold the power stack and PCB rigidly. The cured molding compound, being a dielectric, can also provide thermal conductivity between the die substrate and the die clip. In some embodiments, some or all of the PCB with the switch module components mounted thereon, including the power stack, is uncovered. However, for ease of explanation, the remainder of the disclosure will assume that the switch module is substantially covered with plastic unless otherwise noted.

[0123] (Switch Module 300) 3g-1 to 3g-3 are semi-schematic diagrams illustrating relevant components of an exemplary switch module 300 that can be utilized in the packaged switch 200 of FIGS. 3a-1 to 3a-3. The relevant components of the switch module 300 are viewed from the top, side, and back in FIGS. 3g-1 to 3g-3, respectively.

[0124] The switch module 300 includes a rigid PCB 214. Metal traces, symbolically represented, are formed on the PCB 214. Components of the switch module 300, including the gate driver 306, the temperature sensor T_Sense, the current sensor I_Sense, and the voltage sensor V_Sense, are implemented on the PCB 214 and electrically connected to traces thereon. V_Sense generates a voltage signal Vv based on the voltage across the current terminals of the switch 304. To reduce the voltage input to V_Sense, a voltage divider may be implemented on the PCB 214 and electrically connected between V_Sense and the current terminals.

[0125] The switch module 300 includes a set 314 of connector leads, including connector leads 204 and 206. First ends of these connector leads are connected (e.g., soldered) to respective traces such that the connector leads extend laterally from the PCB 214, as shown in FIGS. 3g-1 and 3g-2. FIG. 3g-2 shows only connector lead 204, but how it and the other connector leads of the set 314 extend laterally from the PCB 214 and are contained in a plane parallel to the plane containing the traces of the PCB 214. Second, opposite ends of the connector leads may be received in a connector (not shown) that is external to the packaged switch (e.g., packaged switch 200) or packaged half-bridge (e.g., packaged half-bridge 250) in which the switch module 300 is included.

[0126] The gate driver 306 is attached to the PCB 214 near the front side. The T_Sense and I_Sense are located between the PCB 214 and a power stack consisting of a switch 304 sandwiched between a die substrate 312 and a die clip 316. The power stack is supported by the PCB 214 and located near the back side. For ease of explanation, in this embodiment the switch 304 consists of two SiC MOSFETs.

[0127] The switch module 300 includes one or more die substrate supports and one or more die clip supports. The supports secure the power stack to the PCB 214. The supports hold the power stack securely above the PCB 214. One or more die substrate supports secure the die substrate 312 to the PCB 214, and one or more die clip supports secure the die clip 316 to the PCB 214. The supports are symbolically shown in Figures 3g-1-3g-3. Although Figures 3g-1-3g-3 show a single die substrate support 216 and a single die clip support 220, it will be understood that additional die substrate supports and die clip supports may be utilized.

[0128] A PCB-based switch module such as switch module 300 can be covered with a plastic such as a mold compound to provide additional structural support between the power stack and the PCB. In an alternative embodiment, the power stack with the supports attached can be substantially covered with a mold compound prior to mounting to the PCB. The die clip and die substrate supports can extend from the case material and the ends of the supports can be connected (e.g., soldered) to traces of the PCB, including PCB 214. The PCB with the mounted components and covered power stack can then be entirely covered with a mold compound material, which can be of a different type than the mold compound used to cover the power stack. For example, a mold compound containing alumina can be used to cover the power stack and a mold compound without alumina can be used to cover the combination of the mounted components and covered power stack and the PCB. In an alternative embodiment, the switch module is not covered in a mold compound. In yet another embodiment, the switch module can be only conformal coated.

[0129] Each of the die clip or die substrate supports can have a circular, square, or rectangular cross-sectional shape, although other cross-sectional shapes are contemplated. The supports can be formed from a conductive metal, such as copper. In addition to providing mechanical support, the die substrate supports 216 can be part of the electrical connection between the die substrate 312, the gate driver 306, and the V_Sense, and the die clip supports 220 can be part of the electrical connection between the die clip 316, the gate driver 306, and the V_Sense.

[0130] Each support 216 or 220 may extend laterally between opposing ends. One end of the die substrate support 216 may include a substantially flat surface that is connected (e.g., soldered) to a trace on the PCB 214, and the other end may include a substantially flat surface that is connected (e.g., soldered, laser welded, etc.) to the die substrate 312. The die substrate support 216 may extend vertically from the trace to which it is connected. In addition to supporting the die substrate 312, the die substrate support 216 provides Vdrain, the voltage at the drain of the switch 304, to V_Sense and the gate driver 306 via the trace to which the die substrate support 216 is connected. One end of the die clip support 220 may include a substantially flat surface that is connected (e.g., soldered) to a trace on the PCB 214, and the other end may include a substantially flat surface that is connected (e.g., soldered) to the die clip 316. The die clip support 220 may extend vertically from the trace to which it is connected. In addition to supporting the die clip 316, the die clip support 220 provides Vsource, which is the voltage source at the source of the switch 304, to V_Sense and to the gate driver 306. The die substrate support 216 and the die clip support 220 can be attached to the die substrate 312 and the die clip 316, respectively, after the switch 304 is connected (e.g., sintered) to the die substrate 312 and the die clip 316, and before the die substrate support 216 and the die clip support 220 are connected (e.g., soldered) to their respective traces on the PCB 214.

[0131] The supports 216 and 220 should be long enough to provide sufficient separation S (see FIG. 3g-3) between the die clip 316 and the PCB 214 to accommodate the T_Sense and I_Sense between the PCB 214 and the die clip 316. In an alternative embodiment where the T_Sense and / or I_Sense engage and support the die clip 316, the number of supports 216 and 220 or other support structures can be reduced or eliminated. However, an electrically insulating adhesive may be required to securely attach the die clip 316 to the top of the T_Sense and / or I_Sense. In this alternative embodiment, at least one conductor such as a post, lead, bond wire, etc. may be required to establish an electrical connection between the V_Sense, the die substrate, and the gate driver 306 through the diode 308 (not shown). At least one conductor such as a post, lead, or bond wire may be required to establish an electrical connection between the V_Sense, the gate driver 306, and the die clip.

[0132] The switch module 300 also includes a gate lead 218, which may take the form of a flat lead with two ends connected together by an intermediate portion. The first end is connected (e.g., soldered) to a trace on the PCB 214, which in turn is connected to an output of the gate driver 306 via resistors R1 and R2. The second end may be connected to the die substrate 312 via an intervening electrically insulating material such that the gate lead 218 is insulated from the die substrate 312. The flat surface of the second end facing the die substrate 312 may provide an area to which one or more wires are bonded. The other end of the one or more bond wires may be attached to a gate of a transistor of the switch 304. The switch 304 may include multiple transistors. The second end of the gate lead 218 may be widened to accommodate multiple bond wires connecting the gate lead 218 to the gates of multiple transistors. The switch 304 is included in a plane separated vertically from a plane including the PCB trace. The bend between the middle and end of the gate lead 218 can correspond to the separation between the two planes. The gate lead 218 can be attached to the die substrate 312 before or after the switch 304 is attached (e.g., sintered) to the die substrate 312 and / or the die clip 316. Alternatively, a flexible PCB or bond wires can be used instead of leads to electrically connect the gate driver 306 to the switch 304. In embodiments where a multi-transistor gate driver is utilized, a second gate lead can be added. The gate lead 218 and the second gate lead can respectively carry gate control voltages Vg1 and Vg2 (not shown) provided by the multi-transistor gate driver. The gate lead 218 and the second gate lead should be in the respective electrical paths between the respective outputs of the multi-transistor gate driver and the respective gates of the respective transistors of the switch 304. The second gate lead can be similar to the gate lead 218 described above.

[0133] 3i-1-3 show one embodiment of the switch module 300 shown in FIGS. 3g-1-3g-3 from top, side and back views. The switch module 300 includes exemplary supports 216 and 220 in the form of metal posts or pedestals. FIGS. 3i-1-3 also show an exemplary die substrate 312 and an exemplary die clip 316, which may be formed from a thin sheet (e.g., 0.1 mm to 2.0 mm) of composite or layered material as described above. FIGS. 3i-1-3 show top, side and back views of an exemplary die substrate 312 formed from a thin sheet of layered material. FIGS. 3i-1-3 also show top, side and back views of an exemplary die clip 316 formed from a thin sheet of composite or layered material. In one embodiment, the die substrate 312 shown in Figures 3i-1-3 is substantially similar in shape to the die substrate 312 shown in Figures 9a-9c of U.S. Patent Application No. 17 / 191,805. In one embodiment, the die clip 316 shown in Figures 3i-1-3 is substantially similar in shape to the die clip 316 shown in Figures 11a-11c and 11e of U.S. Patent Application No. 17 / 191,805.

[0134] A switch 304 (FIG. 3i-3) consisting of a pair of SiC MOSFETs N1 and N2 is attached (e.g., sintered) between an exemplary die substrate 312 and an exemplary die clip 316. The die substrate 312 has opposing substantially flat surfaces. The drain terminals of the SiC MOSFETs N1 and N2 can be attached (e.g., sintered) to one surface, while the opposing surface of the exemplary die substrate 312 includes the die substrate terminal 230.

[0135] The die clip 316 includes a pedestal 1104 that can be formed using a punch press or similar tool. The pedestal 1104 should have a uniform thickness and extend perpendicularly from the surface of the die clip 316 as shown, with a length that can be half or less than the thickness of the die clip 316. The end faces of the pedestal 1104 can be sintered to the source terminals of the SiC MOSFETs N1 and N2. The end faces of the pedestal 1104 are preferably substantially flat and substantially similar in shape (e.g., substantially rectangular) and size (e.g., 1 mm x 4 mm), but slightly smaller than the surface of the source terminals. This ensures that the pedestal 1104 does not contact the SiC MOSFETs N1 and N2 outside of the area occupied by the source terminals. The wider end faces of the pedestal 1104 should more evenly distribute any mechanical stress applied to the SiC MSOFETs N1 and N2, thereby reducing the risk of fracture. Distributing mechanical stresses can be important in embodiments where a packaged switch or packaged half-bridge is "press-packed" against a heat sink, a bus bar, a bus bar that also functions as a heat sink, or other structure. Also, the size and shape of the end face of the pedestal 1104 reduces the possibility of unwanted hot spots caused by concentrated current flow through a narrow point connection to the source terminal, as would be the case if a bond wire were used instead of a die clip. Additionally, the cross-sectional area of ​​the pedestal 1104 (e.g., 25 mm 2 , 16mm 2 , 8mm 2 , 6mm 2 , 4mm 2 , 2mm 2 , or a larger or smaller area) can reduce parasitic inductance and resistance, especially when compared to the parasitic inductance and resistance of bond wires. The die clip 316 includes a substantially flat surface that forms the die clip terminal 232. Additionally, the die clip 316 includes a constricted portion 1108 thereunder upon which an I_Sense circuit can be placed to measure current flow to or from the switch 304.

[0136] 3i-1-3, an exemplary switch module 300 includes one die substrate post 216, one die clip post 220, and one gate lead 218. For ease of illustration, the lead 218 is not shown in FIG. 3i-3. The posts support the power stack on the PCB 214. In another embodiment, multiple die substrate posts support the die substrate 312, and multiple die clip posts support the die clip 316. Each of the posts can have a circular, square, or rectangular cross-sectional shape, and other shapes are also contemplated. The posts can be formed of a conductive metal, such as copper. In addition to providing mechanical support, the die substrate post 216 is part of the electrical connection between the die substrate 312 on one side and the V_Sense and gate driver 306 on the other side, and the die clip post 220 is part of the electrical connection between the die clip 316 on one side and the gate driver 306 and V_Sense on the other side.

[0137] Each example post 216 or post 220 extends laterally between two ends. One end of the example die substrate post 216 can include a substantially flat surface that is connected (e.g., soldered) to a trace on the PCB 214, and the other end can include a substantially flat surface that is connected (e.g., soldered) to the die substrate 312. The example die substrate post 216 can extend vertically from the trace to which it is connected. In addition to supporting the die substrate 312, the example die substrate post 216 provides Vdrain, the voltage at the drain of the switch 304, to V_Sense and the gate driver 306 via the trace to which it is connected. One end of the example die clip post 220 can include a substantially flat surface that is connected (e.g., soldered) to a trace on the PCB 214, and the other end can include a substantially flat surface that is connected (e.g., soldered) to the die clip 316. The example die clip post 220 can extend vertically from the trace to which it is connected. In addition to supporting the die clip 316, the exemplary die clip post 220 provides Vsource, which is the voltage source at the source of the switch 304, to V_Sense and to the gate driver 306. Vsource can be provided to V_Sense through a voltage divider. The exemplary die substrate post 216 and the exemplary die clip post 220 can be attached to the die substrate 312 and the die clip 316, respectively, after the switch 304 is connected (e.g., sintered) to the die substrate 312 and the die clip 316, and before the die substrate post 216 and the die clip post 220 are connected (e.g., soldered) to the respective traces on the PCB 214.

[0138] The exemplary gate lead 218 of FIGS. 3i-1 and 3i-2 may be formed from a thin metal sheet having first and second extensions that are integrally connected and perpendicular to each other. The first extension of the gate lead 218 includes two ends that are integrally connected by a middle section. Two right angle joints connect the two ends to the middle section. The first end is connected (e.g., soldered) to a trace on the PCB 214, which is connected to an output of the gate driver 306. The second end is connected to a second extension that is connected to the die substrate 312 via an electrically insulating material (not shown). A bond wire BW connects the second extension of the gate lead 218 to the gate (not shown) of the MOSFET N1 in the figure. A similar bond wire connects the second extension of the gate lead 218 to the gate of the other MOSFET N2. In an alternative embodiment, instead of the rigid gate leads 218 formed from thin wall, a flex PCB can be used for the connection between the gate driver and the gate.

[0139] (Switch module 303) 3h-1 to 3h-3 show an example of a switch module 303 that can be used in the packaged switch 201 of FIG. 3b-1 to 3b-3. The switch module 303 of FIG. 3h-1 to 3h-3 is similar to the switch module 300 shown in FIG. 3g-1 to 3g-3, but the die clip terminal 232 is arranged near the right side of the rigid printed circuit board 219. FIG. 3j-1 to 3j-3 show an embodiment of the switch module 303 shown in FIG. 3h-1 to 3h-3. The switch module 303 of FIG. 3j-1 to 3j-3 is similar to the switch module 300 of FIG. 3i-1 to 3i-3, but the die clip terminal 232 is arranged near the right side of the rigid PCB 219.

[0140] (Switch Module 305) The switch modules 300 and 303 allow for single-sided cooling of the switch 304. FIGS. 3k-1-3k-4 show an example switch module 305 that allows for double-sided cooling of the switch 304 consisting of MOSFETs N1 and N2. The components of the switch module 305 are connected to each other via traces on the rigid PCB 221. The switch module 305 can be used with the example packaged switch 211 shown in FIGS. 2c-1, 2c-2, 3e-1 and 3e-2.

[0141] 3k-1-3k-4, the switch module 305 is similar to the switch module 300 shown in FIGS. 3i-1-3i-3. There are some important differences. For example, the die clip 316 of the switch module 300 is replaced with an exemplary die clip 345 having two die clip terminals 232 and 344. The PCB 214 is replaced with the PCB 221, which is C-shaped to accommodate double-sided cooling of the switch 304. In addition, the T_Sense is mounted on the PCB 221, but is not located under the switch 304. There may be further differences between the switch modules 300 and 305.

[0142] Similar to module 300, switch module 305 includes supports 216 and 220 in the form of metal posts or pedestals that support a power stack on a PCB 221. The power stack is comprised of a die substrate 312 and a switch 304 sandwiched between a die clip 345.

[0143] 3k-1-3k-4 are top, bottom, side and rear views of an exemplary die substrate 312 and an exemplary die clip 345. The exemplary die substrate 312 may be formed from a thin sheet (e.g., 0.1 mm to 2.0 mm) of a composite or layered material including layers of molybdenum between layers of copper. In one embodiment, the exemplary die clip 345 may be formed by attaching (e.g., sintering, soldering, etc.) a cube-shaped portion 350 of copper or other metal to the die clip 316 (see, e.g., FIGS. 3j-1 and 3j-2). More specifically, a rectangular, substantially flat surface of the cube-shaped portion 350 may be attached to a substantially flat surface of the die clip 316 (FIGS. 3j-1 and 3j-2) that faces the surface attached to the switch 304 of MOSFETs N1 and N2. The opposing flat surface of the cube-shaped portion 350 includes the die clip terminal 344. In another embodiment, the die clip 345 is machined or 3D printed from a solid piece of metal such as copper.

[0144] A switch 304 consisting of a pair of SiC MOSFETs N1 and N2 is attached (e.g., sintered) between an exemplary die substrate 312 and an exemplary die clip 345. The die substrate 312 has opposing substantially flat surfaces. The drain terminals of the SiC MOSFETs N1 and N2 are attached (e.g., sintered) to one surface, and the opposing surface of the die substrate 312 includes the die substrate terminal 230. As described above, each switch in the power stack can include multiple transistors connected in parallel between the die clip and the die substrate. The parallel connection allows a larger current to flow through the switch when activated or turned on.

[0145] The die clip 345 includes a substantially flat surface that forms the die clip terminal 232. The die clip 345 includes a pedestal 1104 that extends perpendicularly from the surface of the die clip 345 as shown. The end faces of the pedestal 1104 can be sintered to the respective source terminals of the SiC MOSFETs N1 and N2. The end faces of the pedestal 1104 are substantially flat and preferably substantially similar in shape (e.g., substantially rectangular) and size (e.g., 2.5 mm x 4 mm) but slightly smaller than the surface of the source terminals to which they are attached. This ensures that the pedestal 1104 does not contact the SiC MOSFETs N1 and N2 outside of the area occupied by the source terminals. The wider the end face of the pedestal 1104, the more evenly mechanical stresses applied to the SiC MOSFETs N1 and N2 should be distributed, thereby reducing the risk of fracture. Distributing mechanical stress can be important in embodiments where the packaged switch or packaged half-bridge with switch module 305 is pressed against a bus bar, heat sink, or other structure. The size and shape of the end face of pedestal 1104 also reduces the possibility of undesirable hot spots caused by concentrated current flow through a narrow point connection to the source terminal, as would occur if a bond wire were used instead of a die clip. The large cross-sectional area of ​​pedestal 1104 (e.g., 25 mm 2 , 16mm 2 , 8mm 2 , 6mm 2 , 4mm 2 , 2mm 2, or one or more cross-sectional areas) reduces the density of current flow, which can reduce parasitic inductance and resistance, especially when compared to the parasitic inductance and resistance of a bond wire if a bond wire were used instead of the die clip with the pedestal 1104. Additionally, the larger cross-sectional area and wider end faces of the pedestal 1104 allow the die clip 345 to transfer more heat from the power stack through the die clip terminals 344. If the die clip terminals 344 are thermally connected to a heat sink or a bus bar that also functions as a heat sink, the rate at which heat is transferred from the power stack can be increased. Finally, the die clip includes a constriction 1108 beneath which an I_Sense circuit can be placed to measure the current flowing to or from the switch 304.

[0146] The switch module 305 includes one or more die substrate posts, one or more die clip posts, and a gate lead. The posts can support a power stack above the PCB 221. In one embodiment, one or more die substrate posts support a die substrate 312, and one or more die clip posts support a die clip 345. Each of the posts can have a circular, square, or rectangular cross-sectional shape, although other shapes are contemplated. The posts can be formed from a conductive metal, such as copper. With reference to FIGS. 3k-1-3k-4, the exemplary switch module 305 includes one exemplary die substrate post 216, one exemplary die clip post 220, and an exemplary gate lead 218. In addition to providing mechanical support, the die substrate posts 216 are part of the electrical connection between the die substrate 312 on one side and the V_Sense and gate driver 306 on the other side, and the die clip posts 220 are part of the electrical connection between the die clip 345 on one side and the gate driver 306 and V_Sense on the other side.

[0147] Each exemplary post 216 or post 220 extends laterally between two ends. One end of the die substrate post 216 can include a substantially flat surface that is connected (e.g., soldered) to a trace on the PCB 221, and the other end can include a substantially flat surface that is connected (e.g., soldered) to the die substrate 312. The die substrate post 216 can extend vertically from the trace to which it is connected. In addition to supporting the die substrate 312, the die substrate post 216 provides Vdrain, the voltage at the drain of the switch 304, to V_Sense and the gate driver 306 via the trace to which it is connected. One end of the die clip post 220 can include a substantially flat surface that is connected (e.g., soldered) to a trace on the PCB 221, and the other end can include a substantially flat surface that is connected (e.g., soldered) to the die clip 345. The die clip post 220 can extend vertically from the trace to which it is connected. In addition to supporting the die clip 345, the die clip post 220 provides the vias that are the voltage sources at the source of the switch 304 to V_Sense and to the gate driver 306 through the traces to which it is attached. The die substrate post 216 and the die clip post 220 can be attached to the die substrate 312 and the die clip 316, respectively, after the switch 304 is connected (e.g., sintered) to the die substrate 312 and the die clip 345, and before the die substrate post 216 and the die clip post 220 are connected (e.g., soldered) to their respective traces on the PCB 221.

[0148] Posts 216 and 220 should be long enough to form a sufficient separation distance S (FIG. 3k-4) between the die clip 345 and the PCB 221 so that I_Sense can be located between the PCB 221 and the narrowed portion 1108 of the exemplary die clip 345.

[0149] The exemplary gate lead 218 of FIGS. 3k-1-3 may be formed from a thin metal sheet having first and second extensions that are integrally connected and perpendicular to one another. The first extension includes two ends that are integrally connected by a middle section. The first extension includes two right angle joints that connect the two ends to the middle section. The first end is connected (e.g., soldered) to a trace on the PCB 221, which is connected to an output of the gate driver 306. The second end is connected to a second extension that is connected to the die substrate 312 via an electrically insulating material (not shown). A bond wire BW connects the second extension of the gate lead 218 to the gate (not shown) of the MOSFET N1 in the figure. A similar bond wire connects the second extension of the gate lead 218 to the gate of the other MOSFET N2.

[0150] 3k-2, PCB 221 has a shape that supports the power stack while exposing die clip terminals 344 through the case of the packaged switch in which it is contained, such as packaged switch 211, so that the die clip terminals 344 can be thermally and / or electrically connected to a heat sink or a bus bar that also functions as a heat sink. PCB 221 includes extensions 222 and 224. In the illustrated embodiment, an exemplary die clip support 220 is connected to traces on extension 224.

[0151] (Switch Module 307) 3l-1 to 3l-4 show a switch module 307, which is similar to the switch module 305, but with the die clip terminals 232 located near the right side of the rigid PCB 223. The switch module 307 allows for double-sided cooling of the switch 304 consisting of MOSFETs N1 and N2. The switch module 307 can be used with the packaged switch 209 of FIGS. 3f-1 and 3f-2.

[0152] (Switch modules 319 and 321) 3k-1-3k-4 and 3l-1-3l-4 show switch modules 305 and 307, respectively, configured for double-sided cooling of a switch 304 consisting of MOSFETs N1 and N2. These switch modules have die clip terminals 344. When encased to create a packaged switch, the die clip terminals 344 can protrude from the plastic case so that they can be press-fitted to a bus bar or heat sink.

[0153] 3m-1-3m-4 and 3n-1-3n-4 show alternative switch modules configured for double-sided cooling of switch 304. FIGS. 3m-1-3m-4 show top, bottom, side and rear views of an exemplary switch module 319, and FIGS. 3n-1-3n-4 show top, bottom, side and rear views of an exemplary switch module 321. Switch modules 319 and 321 are substantially similar to switch modules 305 and 307, respectively. Die clip 345 is replaced with die clip 316, each of which includes a surface that includes die clip terminals 318 that can be electrically and thermally connected to a bus bar or heat sink. Switch modules 319 and 321 can be encased in plastic, for example using transfer molding, to create a packaged switch module with die clip terminals 318 recessed below the plastic case. The pedestals of the busbar or heat sink may extend through openings in the plastic case, allowing flat surfaces of these pedestals to be press-fit, sintered, or otherwise connected to corresponding surfaces of the die clip terminals 318. The connection of the pedestals to the die clip terminals 318 allows heat and / or current to flow between the switch 304 and the connected heat sink or busbar, which also functions as a heat sink. Before the switch modules 319 and 321 are covered with plastic, the recesses in the die clip 316 formed when the pedestals 1104 were stamped may be filled with an electrically and thermally conductive material, as described below, to facilitate the flow of heat and current between the switch 304 and the busbar or heat sink to which it is connected via the die clip 316 and terminals 318.

[0154] (Switch Module 376) Some packaged switches, such as packaged switches 247s and 247d shown in Figures 2d-1 and 2e-1, respectively, have switch modules that lack a switch controller and certain other components such as V_Sense, I_Sense, and V_Sense. With continued reference to Figures 2d-1 and 2e-1, Figures 3p-1 through 3p-11 show the assembly of components to form an exemplary switch module that may be utilized in packaged switches 247d or 247s.

[0155] FIG. 3p-1 shows top and side views of an exemplary die substrate 360 ​​and an exemplary connector lead 288g, each of which may be formed (e.g., stamped, cut, etc.) from a thin sheet (e.g., 0.1 mm to 2.0 mm) of a composite or layered material including a thin layer of molybdenum between thin layers of copper. The connector lead 288d is integrally connected to the die substrate 360. In another embodiment, the connector lead 288s may be attached (e.g., soldered) to the die substrate 360. The die substrate 360 ​​includes opposing substantially flat surfaces, one of which is designated 362 and the other of which includes the die substrate terminal 230. In one embodiment, the die substrate 360 ​​has a width ws=13.5 mm and a length ls=16.5 mm. In one embodiment, the gate connector lead 288g has a width wgl=1.2 mm and a length lgl=20 mm. Connector lead 288g is contained within the same plane as connector lead 288d in FIG. 3p-1. Connector lead 288g and die clip 360 are both estimated to be 1.0 mm thick. Connector-leads 288d and 288g are similarly shaped in FIG. 3p-1. FIG. 3p-2 shows connector leads 288d and 288g after they have been bent. Bond pad 361 provides a surface area where a bond wire can electrically connect connector lead 288g to a gate lead, described below.

[0156] FIG. 3p-3 shows the structure of FIG. 3p-2 after an exemplary switch, gate lead 364, bond wire 365, and bond wire 366 have been added. The exemplary switch is mounted on a flat surface 362 and includes four transistors (e.g., SiC MOSFETs) N1-N4, although it is understood that in alternative embodiments, fewer or more transistors may be utilized. A first current terminal (e.g., drain) of each transistor N1-N4 may be soldered, brazed, sintered, or otherwise attached to a surface 362 of the die substrate 360. A thin gate lead 364, which may be formed of a conductive metal such as copper, may also be attached to the surface 362 via an electrical insulator layer (not shown). Bond wires 366 of substantially equal length electrically connect the gate leads 364 to the respective gates (not shown) of N1-N4. In alternative embodiments, multiple sets of equal length bond wires connect the gate leads 364 to the respective gates, with each set having two or more bond wires. Connector lead 288g is electrically connected to gate lead 364 via a bond wire 365 that has one end attached to bond pad 361. In an alternative embodiment, multiple bond wires 365 connect gate lead 364 to bond pad 361.

[0157] FIG. 3p-4 shows the structure of FIG. 3p-3 after a bridge 368 has been added. The bridge 368 can be formed from a material that contributes to forming a strong sintered connection to the transistors N1-N4 and the die clip. The bridge 368 can include a pedestal, such as the pedestal 1104. The flat ends of the pedestal 1104 can be soldered, welded, sintered, or otherwise attached to the second current terminals (e.g., sources) of the transistors N1-N4. For ease of explanation, each of the transistors N1-N4 has a pair of second current terminals, although it is understood that the transistors may have fewer than two or more than two current terminals. The flat ends of the pedestal 1104 can be plated with a material that strengthens the sintered connection with the second current terminals of the transistors N1-N4. The bridge 368 can be electrically and thermally attached (e.g., sintered) to the die clip, as described in more detail below.

[0158] The exemplary bridge 368 may be formed (e.g., stamped, cut, etc.) from a thin sheet (e.g., 0.1 mm to 8.0 mm) of metal (e.g., copper), composite, or layered material (e.g., layers of molybdenum between layers of copper). In another embodiment, the bridge 368 may be 3D printed, extruded, etc. The pedestal 1104 may be formed using a punch press or other tool. In the case of a punch press, any voids left may be filled with electrically and thermally conductive material to form a substantially flat surface that may be attached to a die clip. Alternatively, the pedestal 1104 may be attached to the bridge 368 using soldering, brazing, sintering, or other methods.

[0159] The pedestals 1104 have a uniform thickness and extend vertically from the bottom surface of the bridge 368 as shown, and their length can be half or less than the thickness of the bridge 368. The end faces of the pedestals 1104 can be sintered to the second current terminals of each of the transistors N1-N4. The end faces of the pedestals 1104 should be substantially flat with a shape (e.g., substantially rectangular) and size (e.g., 2.5 mm x 4 mm) that is substantially similar to, but slightly smaller than, the shape and size of the substantially flat surfaces of the respective second current terminals to which they are electrically and thermally attached. This ensures that the pedestals 1104 do not contact the transistors N1-N4 outside of the area occupied by the second current terminals. The wider end faces of the pedestals 1104 should also distribute any mechanical stress more evenly, thereby reducing the risk of transistor destruction.

[0160] FIG. 3p-5 shows top and side views of an exemplary die clip 372 and exemplary connector leads 288s that can be formed (e.g., stamped, cut, etc.) from a thin sheet (e.g., 0.1 mm to 2.0 mm) of composite or layered material. The connector leads 288s are integrally connected to the die clip 372. In another embodiment, the connector leads 288s can be attached (e.g., soldered) to the die clip 372. FIG. 3p-6 shows the die clip 372 after the connector leads 288s have been bent. The die clip 372 includes opposing substantially flat surfaces 344 and 375. The surface 344 defines a die clip terminal configured for thermal and electrical connection to a device such as a bus bar, as described in more detail below. In one embodiment, the die clip 372 has a width wdc=7 mm and a length ldc=17 mm.

[0161] Fig. 3p-7 is a top view and diagram of the structure shown in Fig. 3p-4 (i.e., switch module 376) after the exemplary die clip 372 of Fig. 3p-6 has been attached to bridge 368. A particularly flat surface 375 of die clip 372 can be soldered, welded, sintered, or otherwise attached to bridge 368. Surface 375 can be plated with a material that enhances the sintered connection with bridge 368.

[0162] After the die clip 372 is attached to the bridge 368, a case can be formed around the switch module 376 using, for example, transfer molding to create, for example, the packaged switch 247 shown in Figures 2d-1 and 2d-2, or a case can be formed around the switch module 376 to create the packaged switch 247d shown in Figures 2e-1 and 2e-2.

[0163] In FIG. 3p-4, a bridge 368 has been added to the structure shown in FIG. 3p-3 to allow electrical and thermal connection to the die clip 372, as shown in FIG. 3p-7. In another embodiment, a pedestal can be added to the structure shown in FIG. 3p-3 to allow electrical and thermal connection to the die clip 372. FIG. 3p-8 shows the structure of FIG. 3p-3 after a pedestal 1105 has been added, which may be made of a metal (e.g., copper), composite material, or material layer. The pedestal 1105 in FIG. 3p-8 may be substantially similar in size and structure to the pedestal 1104 shown in FIG. 3p-4, except for its height, which may be greater. The flat end of the pedestal 1105 may be soldered, welded, sintered, or otherwise attached to the second current terminals (e.g., sources) of the transistors N1-N4. The flat end of the pedestal 1105 may be plated with a material that enhances the sintered connection with the second current terminals of the transistors N1-N4. The opposing flat ends of the pedestal can be electrically and thermally attached (e.g., sintered) to the die clip 372, as described in more detail below. The opposite end of the pedestal 1105 can be plated with a material to strengthen the sintered connection to the die clip 372. FIG. 3p-9 shows top and side views of the structure shown in FIG. 3p-8 (i.e., switch module 377) after the exemplary die clip 372 of FIG. 3p-6 has been attached to the pedestal 1104. Specifically, the flat surface 375 of the die clip 372 can be attached to the pedestal 1105 by soldering, welding, sintering, or other methods. The surface 375 can be plated with a material to strengthen the sintered connection with the pedestal 1105.

[0164] In FIG. 3p-3, the gates of transistors N1-N4 are electrically connected to gate lead 364. In an alternative embodiment, the gates of the transistors in the switch can be electrically connected to separate gate leads. FIG. 3p-10 shows a pair of gate leads 364-1 and 364-2 attached to surface 362 of die substrate 360 ​​of FIG. 3p-2 through an electrical insulator layer (not shown). Gate leads 364-1 and 364-2 are thinner than gate lead 364. Otherwise, gate leads 364-1 and 364-2 are substantially similar to gate lead 364. Also shown in FIG. 3p-10 is a pair of connector leads 288g-1 and 288g-2 electrically connected to gate leads 364-1 and 364-2 by bond wires 365-1 and 365-2, respectively. Connector leads 288-1 and 288-2 are substantially similar to connector lead 288. Bond wires 366-1 and 366-2 of substantially equal length electrically connect gate lead 364-1 to the respective gates (not shown) of N1 and N2. Bond wires 366-3 and 366-4 of substantially equal length electrically connect gate lead 364-2 to the respective gates (not shown) of N3 and N4. A bridge 368 and die clip 372 can be added to the structure shown in FIG. 3p-10 to create a switch module 379 shown in FIG. 3p-11.

[0165] Exemplary Packaged Half-Bridge (Packaged Half-Bridge 250) In general, a packaged half-bridge can include a pair of switch modules, such as the pair of switch modules 300. The pair of packaged half-bridges need not be identical. For example, a packaged half-bridge can include switch module 300 and switch module 303.

[0166] With continued reference to Figures 2b-1-2b-3, Figures 4a-1-4a-3 are semi-schematic diagrams of an exemplary packaged half-bridge 250 showing some of its components. The packaged switch 250 is shown in Figures 4a-1 and 4a-2 with a transparent case 252 to allow a better understanding of the switch module's components, their interactions, and their relative placement. Figures 4a-1 and 4a-2 show the relative positions of certain components of the packaged half-bridge 250 when viewed from the side and back, respectively.

[0167] The packaged half bridge 250 includes two switch modules 300 of FIG. 3a-1, 3g-1 or 3i-1. More specifically, the packaged half bridge 250 includes a high-side switch module 300H and a low-side switch module 300L. The switch modules are back-to-back inside the packaged half bridge 250, and the high-side switch module 300H is inverted relative to the low-side switch module 300L and placed underneath it before the combination is subsequently encapsulated in a molding compound such as epoxy using, for example, transfer molding. In an alternative embodiment, the components of the high-side module 300H are connected to traces on one side of a rigid PCB and the components of the low-side module 300L are connected to traces on the other side of the rigid PCB.

[0168] 4a-1 and 4a-2 show the relative positioning of certain components of the half bridge 250 with respect to each other. The die substrate 312, the switch 304, and the die clip 316 are stacked vertically as shown between the top T and bottom B. The switch controller 302 is similarly stacked vertically as shown between the top T and bottom B. The switch controller 302 is located near the front F of the packaged half bridge 250, and the power stack including the switch 304 is located near the back Bk. The die substrate terminals 230L and 230H are accessible from the top and bottom of the packaged half bridge 250, respectively, and the die clip terminals 232H and 232L are accessible from the left and right sides of the packaged half bridge 250, respectively. The die substrate terminals 230L and 230H are shown in a position shown to be flush with the top and bottom surfaces T and B, respectively, and the die clip terminals 232L and 232H are shown in a position shown to be flush with the right and left sides R and L, respectively, in FIG. 4a-2. For ease of illustration, the side terminals 242 are not shown.

[0169] The high-side switch 304H is electrically and thermally connected to a high-side die substrate 312H, which has a die substrate terminal 230H for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the terminal 230H can be electrically and / or thermally connected to a V+ bus bar. The high-side switch 304H is also electrically and thermally connected to a high-side die clip 316H, which has a terminal 232H for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the terminal 232H can be electrically and / or thermally connected to a surface of a C-shaped phase bus bar. The low-side switch 304L is electrically and thermally connected to a low-side die substrate 312L, which has a terminal 230L for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the low-side die substrate terminal 230L can be electrically and / or thermally connected to the same C-shaped conductor phase bus bar to which the high-side die clip terminal 232H is connected, or the low-side die substrate terminal 230L can be electrically and / or thermally connected to a heat sink. The low-side switch 304L is electrically and thermally connected to the die clip 316L, which has a terminal 232L for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the terminal 232L can be electrically and / or thermally connected to a V bus bar.

[0170] The high-side switch 304H and the low-side switch 304L of the packaged half-bridge are presumed to be substantially identical in the illustrated embodiment. In other embodiments, the switches 304H and 304L may be substantially different. For example, the high-side switch 304H may take the form of one or more MOSFETs and the low-side switch 304L may take the form of one or more JFETs, or vice versa. Or the high-side switch 304H may include one or more SiC-based transistors and the low-side switch 304L may include one or more GaN-based transistors, or vice versa. In yet other embodiments, the number of transistors utilized in the high-side switch 304H may differ from the number of transistors utilized in the low-side switch 304L. Combinations of the differences in the high-side and low-side switches described above are also contemplated. For example, the high-side switch 304H may take the form of two SiC MOSFETs while the low-side switch 304L may include three Si IGBTs, or vice versa.

[0171] (Packaged Half-Bridge 251) Figures 4b-1 to 4b-3 are semi-schematic diagrams of another packaged half-bridge 251 showing some of its components. Figures 4b-1 and 4b-2 show the relative positions of certain components of packaged half-bridge 251 as seen from the side and rear, respectively, through a transparent case. Figure 4b-3 is a top view of packaged half-bridge 251 with an opaque case.

[0172] Half bridge 251 is similar to packaged half bridge 250, but with at least one difference. Packaged half bridge 251 includes switch module 300 of FIG. 3g-1 or 3i-1 and switch module 303 of FIG. 3h-1 or 3j-1. FIGS. 4b-1 and 4b-2 show the relative positions of certain components of packaged half bridge 251 when viewed from the side and back, respectively. FIG. 4b-2 is oriented to show that low side die clip terminal 232L and high side die clip terminal 232H are flush with the left side.

[0173] Switch modules 300 and 303 are back to back inside packaged half bridge 251. Switch module 300 is placed under switch module 303 before being subsequently encapsulated in a molding compound such as epoxy using, for example, transfer molding. In an alternative embodiment, the components of switch module 300 are connected to traces on one side of a PCB and the components of switch module 303 are connected to traces on the opposite side of the PCB.

[0174] (Packaged Half-Bridge 253) Figures 4c-1 to 4c-3 are semi-schematic diagrams of another packaged half-bridge 253 showing some of its components. Figures 4c-1 and 4c-2 are side and rear views, respectively, showing the relative positions of certain components of packaged half-bridge 253 with a transparent case. Figure 4c-3 is a top view of packaged half-bridge 253 with an opaque case.

[0175] The packaged half-bridge 253 is similar to the packaged half-bridge 250, but the switch module 300 is replaced with the switch module 303 shown in Figure 3h-1 or 3j-1. Figure 4c-2 is oriented to show that the low-side die clip terminal 232L is flush with the right side, and the high-side die clip terminal 232H is oriented to show that it is flush with the left side.

[0176] The high side switch module 303H is inverted relative to the low side switch module 303L and placed underneath it before being substantially encapsulated in a molding compound such as epoxy using, for example, transfer molding. In an alternative embodiment, the components of the high side module 303H are connected to traces on both sides of a PCB and the components of the low side module 303L are connected to traces on the opposite side of the PCB.

[0177] (Packaged Half-Bridge 255) 4d-1-4d-3 are semi-schematic diagrams of yet another packaged half-bridge 255 similar to packaged half-bridge 250. Figs. 4d-1 and 4d-2 show the relative positions of certain components of packaged half-bridge 255 with a transparent case, as viewed from the side and rear, respectively. Fig. 4d-3 is a top view of packaged half-bridge 255 with an opaque case.

[0178] Although packaged half-bridges 250 and 255 are similar, there is at least one substantial difference: die clips 316H and 316L of packaged half-bridge 250 are replaced by a unified die clip 315 that is attached (e.g., sintered) to switches 304H and 304L. More specifically, second current terminals of switches 304H and 304L are sintered to the unified die clip 315. Die clip 315 has a terminal 232 that is substantially similar to die clip terminal 232 of die clip 316. Die clip terminal 232 is positioned to be shown flush with the right side in FIG. 4d-2.

[0179] All switch module components of packaged half-bridge 255 may be implemented on a single PCB in one embodiment. For example, switch controller 302H may be connected to traces on one side of the PCB and switch controller 302L may be connected to traces on the other side of the PCB. The single PCB may need to be shaped like PCB 223 shown in FIG. 3n-2 to accommodate integral die clip 315.

[0180] (Packaged Half-Bridge 259) Figures 4e-1 to 4e-3 are semi-schematic diagrams of another packaged half-bridge 259 showing some of its components. Figures 4e-1 and 4e-2 show the relative positions of certain components of packaged half-bridge 259 as seen through a transparent case and from the side and back, respectively. Figure 43-3 is a top view of packaged half-bridge 259 with an opaque case.

[0181] Half bridge 259 is similar to packaged half bridge 250, but there is at least one substantial difference; die clips 316L and 316H are replaced by die clips 317L and 317H, respectively. Figures 4e-1 and 4e-2 show the relative positions of certain components of packaged half bridge 259 when viewed from the side and back, respectively. Figure 4e-2 shows that low side die clip terminal 232L and high side die clip terminal 232H are positioned to be flush with the left side and right side, respectively. Die clips 317 and 316 are similar in many features. For example, like die clip 316, die clip 317 includes a horizontal portion and a vertical portion. Only the vertical portion of die clip 317 is shown in Figure 4e-1. There is at least one substantial difference between die clips 316 and 317. The horizontal portion of die clip 317 is positioned to extend between the opposing die clip terminals 232 and 233. Both die clip terminals 232 and 233 are accessible through the case of the half-bridge package 259. The die clip terminals 232 and 233 are flush with opposite surfaces of the packaged half-bridge 259 as shown. The die clip terminals 232 and 233 may be similar in shape and size and are configured to carry high currents to and from the packaged half-bridge 259.

[0182] T_Sense H, I_Sense H, and switch controller 302H may be connected to traces on a first PCB within packaged half-bridge 259, while T_Sense L, I_Sense L, and switch controller 302L may be connected to traces on a second PCB in one embodiment. In an alternative embodiment, T_Sense H, I_Sense H, and switch controller 302H are connected to traces on one side of the PCB, and T_Sense L, I_Sense L, and switch controller 302L are connected to traces on the opposite side of the PCB.

[0183] (Packaged Half-Bridge 261) Figures 4f-1 and 4f-2 are semi-schematic diagrams of yet another packaged half-bridge 261 showing some of its components. Figure 4f-1 shows the relative positions of certain components of packaged half-bridge 261 as viewed through a transparent case and from the side. Figure 4f-2 is a top view of packaged half-bridge 261 with an opaque case.

[0184] Half bridge 261 is similar to packaged half bridge 250, except that die clips 316L and 316H are replaced by die clips 347L and 347H, respectively. Figure 4f-1 shows the relative positions of certain components of packaged half bridge 261 when viewed from the side. Figure 4f-1 is oriented to show that low side die clip terminal 232L and high side die clip terminal 232H are flush with the backside.

[0185] T_Sense H, I_Sense H, I_ and switch controller 302H are connected to traces provided by a first PCB, and T_Sense L, I_Sense L and switch controller 302L are connected to traces provided by a second PCB. In another embodiment, T_Sense H, I_Sense H and switch controller 302H are connected to traces provided on one side of the PCB, and T_Sense L, I_Sense L and switch controller 302L are connected to traces provided on the other side of the PCB.

[0186] (Embodiments of packaged half-bridges 250 and 253) With continued reference to Figs. 2b-1 and 2b-2, Figs. 4g-1 and 4g-2 are semi-schematic diagrams of an exemplary PCB-based packaged half-bridge 250 showing some of its components. Figs. 4g-1 and 4g-2 show the relative positions of certain components when the packaged half-bridge 250 is shown in a transparent case from the side and back, respectively. The packaged half-bridge 250 includes two switch modules 300 of Figs. 3g-1 to 3g-3. More specifically, the packaged half-bridge 250 includes a high-side switch module 300H and a low-side switch module 300L. The switch modules face each other inside the packaged half-bridge 250, with the high-side switch module 300H being inverted and placed under the low-side switch module 300L before being encapsulated in a molding compound such as epoxy resin using, for example, transfer molding.

[0187] 4g-1 and 4g-2 show the relative positioning of certain components of the half bridge 250 with respect to each other. The die substrate 312, the switches 304, and the die clip 316 are stacked vertically as shown between the top T and bottom B. The gate drivers 306 are similarly stacked vertically as shown between the top T and bottom B. The gate drivers 306 are located near the front F of the packaged half bridge 250, and the power stacks including the respective switches 304 are located near the back Bk. The die substrate terminals 230L and 230H are accessible from the top T and bottom B of the packaged half bridge 250, respectively, and the die clip terminals 232L and 232H are accessible from the left and right sides of the packaged half bridge 250, respectively. The die substrate terminals 230L and 230H are positioned in the figure to be flush with the top surface T and bottom surface B, respectively, and the die clip terminals 232L and 232H are positioned in Figure 4g-2 to be flush with the left side surface and right side surface, respectively.

[0188] The high-side switch 304H is electrically and thermally connected to a high-side die substrate 312H, which has a die substrate terminal 230H for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the terminal 230H can be electrically and / or thermally connected to a V+ bus bar. The high-side switch 304H is also electrically and thermally connected to a high-side die clip 316H, which has a terminal 232H for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the terminal 232H can be electrically and / or thermally connected to a V+ bus bar. The low-side switch 304L is electrically and thermally connected to a low-side die substrate 312L, which has a terminal 230L for electrically and / or thermally connecting to a device external to the packaged half-bridge 250. For example, the low side die substrate terminal 230L may be electrically and / or thermally connected to a phase bus bar. The low side switch 304L is electrically and thermally connected to a die clip 316L, which has a terminal 232L for electrically and / or thermally connecting to a device external to the packaged half bridge 250. For example, the terminal 232L may be electrically and / or thermally connected to a V bus bar.

[0189] The half bridge 250 includes a pair of PCBs 214L and 214H. A dielectric may be inserted between the PCBs 214L and 214H, which may take the form of an electrically insulating tape (e.g., Kapton tape), or the dielectric may be sprayed onto one or both of the opposing surfaces of the PCBs 214L and 214H. In an alternative embodiment, a single PCB 214 may be utilized that includes traces on opposing surfaces. The components of the high-side switch module 300H (e.g., gate driver 306H, T_SenseH, I_SenseH, die substrate support 216H, die clip support 220H, etc.) are electrically and mechanically connected to traces on one side of the single PCB 214, and the components of the low-side switch module 300L (e.g., gate driver 306L, T_SenseL, I_SenseL, die substrate support 216L, die clip support 220L, etc.) are electrically and mechanically connected to traces on the other side of the single PCB 214. In this alternative embodiment, a four-layer PCB (either a 2x2 layer or a 1x4 layer scenario) can be utilized. The FR4 dielectric layer of the layer PCB can provide electrical isolation between signals on different layers.

[0190] 4h-1 and 4h-2 are schematic diagrams of yet another packaged PCB-based half bridge 253 utilizing switch modules 303. FIGS. 4h-1 and 4h-2 show the relative positions of certain components of the packaged half bridge 253 when viewed from the side and back, respectively. The packaged half bridge 253, shown in a transparent case, is similar to the packaged half bridge 250. Instead of the switch modules 300, the packaged half bridge 253 includes a pair of switch modules 303 of FIGS. 3j-1-3j-3. FIG. 4h-2 shows the low side die clip terminal 232L positioned to show flush with the right side and the high side die clip terminal 232H positioned to show flush with the left side.

[0191] The components of the high-side switch module 303H (e.g., gate driver 306H, T_SenseH, I_SenseH, die substrate support 216H, die clip support 220H, etc.) are electrically and mechanically connected to traces on one side of the single PCB 214, and the components of the low-side switch module 303L (e.g., gate driver 306L, T_SenseL, I_SenseL, die substrate support 216L, die clip support 220L, etc.) are electrically and mechanically connected to traces on the other side of the single PCB 214. In this alternative embodiment, a four-layer PCB (either a 2x2 layer or a 1x4 layer scenario) can be utilized. The FR4 dielectric layer of the four-layer PCB can provide electrical isolation between signals on different layers.

[0192] (Exemplary Air-Cooled Inverter and Rectifier) The air-cooled converter, including the air-cooled inverter and air-cooled rectifier of the present disclosure, can utilize packaged switches and packaged half-bridges. The air-cooled power converter, including the air-cooled inverter and air-cooled rectifier of the present disclosure, has high power density. For example, the air-cooled inverter can provide over 400 kW peak power while occupying a volume of 1.0 liter or less. Volume is conserved in part by stacking packaged switches, packaged half-bridges, heat sinks, bus bars, or bus bars that also function as heat sinks, etc. Volume is also conserved by the elimination of the electromechanical pumps and fluid connection tubes mentioned above. While the present disclosure focuses primarily on air-cooled inverters and air-cooled rectifiers, it is understood that the present disclosure should not be limited thereto.

[0193] (Air-cooled inverter 502i) 5a-1-5 are semi-schematic diagrams of an example of an air-cooled inverter 502i from the end, bottom, left side, right side, and top, respectively. Air-cooled rectifiers and inverters such as inverter 502i utilize packaged switches or packaged half-bridges such as packaged half-bridge 250 shown in FIG. 4a-1 or FIG. 4g-1. For ease of illustration, the packaged switches or packaged half-bridges are shown in clear plastic cases in the example air-cooled inverters and air-cooled rectifiers. Although the packaged switches or packaged half-bridges can include gate drivers and other components, for ease of illustration, only the power stacks (i.e., the switches sandwiched between the die clip and the die substrate) and connector leads of the packaged switches or packaged half-bridges are shown. It is understood that some packaged switch switch modules include only the power stacks and connector leads (e.g., connector leads 288). The power stacks are symbolically shown.

[0194] In some embodiments, the air-cooled inverter or rectifier utilizes a packaged switch or packaged half-bridge having a multi-transistor switch 304. The switch controller for these packaged switches or packaged half-bridges can include a gate driver such as gate driver 306 described above, or alternatively, a multi-transistor gate driver that can independently control each of the transistors of the switch 304, for example with purposefully staggered gate control voltages.

[0195] 5A-2, the air-cooled inverter system 502i has three phases designated a, b, and c. Phases a-c each include a packaged half bridge 250a-c that are disposed between and connected to phase bus bars 524a-c, respectively, and a V+ bus bar 526, as shown.

[0196] The switch may be electrically and thermally connected to a heat sink or a bus bar that also functions as a heat sink. For example, a switch such as switch 304H may be electrically and thermally connected to a bus bar such as V+ bus bar 526, which may also function as a heat sink. The connection may be made by pressing a die substrate terminal such as die substrate terminal 230H against a surface of a bus bar such as V+ bus bar 526. Alternatively, the connection may be made by sintering or soldering a die substrate terminal such as die substrate terminal 230H to a bus bar such as V+ bus bar 526. Other types of connections are contemplated.

[0197] The switches 304L of the packaged half bridges 250a-250c of FIG. 5A-2 are electrically and thermally connected to the phase bus bars 524a-524c, respectively, which also function as heat sinks. These connections may be made by pressing the die substrate terminals 230L against the surface bus bars 524a-524c. Alternatively, the connections may be made by sintering or soldering the die substrate terminals 230L to the surfaces of the phase bus bars 524a-524c. Other types of connections are also contemplated.

[0198] The phase bus bars, including the phase bus bars 524a-524c, must be electrically isolated from each other. The phase bus bars may be electrically connected to respective devices, such as the stator windings of an electric motor. Although not shown in FIGS. 5a-1-5a-5, the phase bus bars 524a-524c are electrically connected to the stator windings Wa-Wc, respectively. Packaged switches, such as the packaged half bridges 250a-250c, or cases of packaged half bridges may be thermally connected to the bus bars, such as the phase bus bars 524a-524c of FIG. 5a-2, respectively.

[0199] The busbars may be made (e.g., extruded, molded, etc.) in whole or in part from a conductive metal such as copper or aluminum, and may have different shapes, sizes, and dimensions (e.g., lengths, widths, heights, etc.) to accommodate different inverter or rectifier designs. The phase busbar 524 and the V+ busbar 526 are rectangular and have the same width W1=12 mm and height H1=27 mm. An exemplary V+ busbar 526 has a length L1=100 mm, and an exemplary phase busbar 524 has a length L2=32 mm.

[0200] (Example Heat Pipe) Heat pipes can be utilized in the air-cooled inverters and rectifiers of the present disclosure. The heat pipes can remove heat from the switches 304 and other devices. The heat pipes can be connected between a bus bar and a heat sink, such as a heat sink that includes flat metal heat sinks (hereinafter "heat fins").

[0201] FIG. 5a-1 is an end view of the air-cooled inverter system 502i. This view shows a packaged half bridge 250c sandwiched between a phase bus bar 524c and a V+ bus bar 526. The ends of the heat pipes can be embedded in the bus bars. FIG. 5a-1 shows an example heat pipe 522 with ends embedded in a phase bus bar 524c and a V+ bus bar 526. A heat pipe, such as heat pipe 522, can extend from the bus bar and connect to a flat metal heat fin, such as heat fin 520. FIGS. 5a-1-5a-4 show the positioning of the packaged half bridge 250, phase bus bar 524, heat fin 520, heat pipe 522, V- bus bar 528, and V+ bus bar 526 relative to each other for each phase.

[0202] The heat pipe may contain a "wick" and a "working" liquid within the sealing tube. A vacuum pump is typically used to remove air from the tube before sealing. Although heat pipes made with rounded tubes (i.e., pipes) are disclosed, it is understood that heat pipes can also be made with tubes of other cross-sectional shapes (e.g., rectangular). The tubes can be made of a material compatible with the working fluid, such as copper for a water heat pipe, or aluminum for an ammonia heat pipe. The amount of working liquid is selected so that the heat pipe contains both vapor and liquid over the operating temperature range.

[0203] Figures 5A-6 show an exemplary heat pipe 522. Heat pipe 522a includes a wick 552 and a liquid, the combination of which is contained within a vacuum-sealed tube 550a made of a metal such as copper or aluminum. In Figures 5a-6, a portion of heat pipe 522a is cut away to show the wick 552 and working liquid. The wick can be attached directly to the inner wall of the heat pipe. Figures 5a-6 also show exemplary heat pipes 522b and 522c in cross section. Heat pipe 522b includes a grooved wick, and heat pipe 522c includes a metal wick structure.

[0204] Each heat pipe extends between two end sections: the evaporator end may be embedded in a busbar, such as the V+ busbar 526 or the phase busbar 524c in FIG. 5a-1, and the condenser end may be attached to a heat sink, such as heat fins 520, using, for example, solder.

[0205] The evaporator ends of the heat pipes are thermally connected to the bus bar. The switches 304 are thermally and electrically connected to the bus bar. Thus, the evaporator ends of the heat pipes can extract heat generated by the switches 304 through the bus bar. In some embodiments, the heat pipes can also be electrically connected to the bus bar.

[0206] The condenser end of the heat pipe can be thermally connected to heat fins made of metal or other material with high thermal conductivity such as AlN. These heat fins can extract heat from the condenser end of the heat pipe. For purposes of illustration, the heat fins are made of metal. In some embodiments, the heat pipe can also be electrically connected to the metallic heat fins.

[0207] In the air-cooled inverter system 502i, the evaporator end of the heat pipe 522 is thermally connected to but electrically insulated from the bus bars 524 and 526, and the condenser end is electrically and thermally connected to the metal heat fins 520. Electrical insulation can be achieved by a thin dielectric layer formed on the cylindrical surface of the inner and / or outer surface of the heat pipe. A wick can also be attached to the inner surface of the heat pipe through a thin dielectric layer. For ease of explanation, no dielectric is formed on the inner surface of the heat pipe unless otherwise noted.

[0208] All or a portion of the exterior surface of the heat pipe may be covered with a thin layer of dielectric material, or may be entirely uncovered. The evaporator end of a heat pipe, such as heat pipe 522 of inverter 502i, may be covered with a thin dielectric layer 536 (see, e.g., FIG. 5a-2) to electrically insulate the heat pipe from the bus bar in which it is contained, while the remainder of the heat pipe is largely uncovered. To enhance heat transfer, a thin metal layer, thermal grease, or thermal paste may be applied to the dielectric layer filling any empty gaps or spaces at the interface between the dielectric layer and the bus bar in which the heat pipe is embedded. In another embodiment, the evaporator end is thermally and electrically connected to a bus bar, such as bus bars 524 and 526, and the condenser end is thermally connected to a heat fin, such as metal heat fin 520, but is electrically insulated from the heat fin. Electrical isolation in this other embodiment may be provided by a thin dielectric layer formed on the exterior surface of the condenser end, while the remainder of the heat pipe beneath the heat fin is uncovered. To enhance heat transfer in this alternative embodiment, a thin metal layer, thermal grease or thermal paste can be applied to fill the air gap or space at the interface between the uncovered portion and the bus bar with the heat pipe embedded in it.

[0209] A working heat pipe utilizes a phase change. More specifically, heat from a switch 304 or other device is transferred to a liquid inside the heat pipe at the evaporator end. The heat vaporizes the liquid and the vapor travels along the inner cavity of the heat pipe to the condenser end. At the condenser end, heat from the vapor is exchanged with heat fins and the vapor condenses back into a liquid that is absorbed by the wick. The condensed liquid returns to the evaporator end section and the cycle continues.

[0210] The most common fluids used in heat pipes include water, ammonia, acetone, and methanol. At intermediate temperatures, water is the ideal working fluid due to its high latent heat and boiling point. At low temperatures, ammonia, acetone, and methanol are suitable.

[0211] The performance of a heat pipe is determined primarily by its wick. The wick serves several functions. The first function is to allow for the backflow of liquid from the condenser end to the evaporator end, the second function is to allow for heat transfer to the liquid, and the third function is to provide space for the liquid / vapor phase change. Heat pipes are made with various types of wick structures, such as sintered wicks, grooved wicks, and screen mesh wicks. Sintered wicks allow for high heat transfer and wide operating angles. Figures 5a-6 are cross-sectional views of an example heat pipe 522b including a grooved wick. The exemplary wick is a "flower" shape with a ring of small cylindrical subchannels having substantially the same cross section and in fluid communication with a centrally located cylindrical subchannel that may be larger in cross section when compared to that of the cylindrical subchannels in the ring. Each spoke subchannel allows for fluid communication between each cylindrical subchannel in the ring and the centrally located cylindrical subchannel. Each spoke subchannel can have any one of a number of cross-sectional shapes. In the illustrated embodiment, each spoke subchannel is substantially rectangular in cross section, although square or circular cross sections are also contemplated. Grooved wicks are lightweight and low cost, but have limited operating angles and are often gravity dependent. Screen mesh wicks combine characteristics of both sintered and grooved wicks and are preferred for some applications. The most common screen mesh consists of woven copper mesh. Screen mesh wicks are made by wrapping a metal cloth or mesh around a forming mandrel, which is then inserted into the tube. Once in place, the mandrel is carefully removed leaving the wrapped mesh behind. The mesh attempts to unroll on its own, holding the wick in place by tension against the inner wall of the tube.

[0212] The busbars of the present disclosure, including phase busbars, V-busbars, and / or V+ busbars, may include channels through which heat pipes are received. More specifically, the channels may receive the evaporator ends of the heat pipes. For ease of explanation, all V+ busbars are presumed to have channels that receive the evaporator ends of the heat pipes unless otherwise noted. Additionally, all V- or phase busbars that also function as heat sinks are presumed to have channels that receive the evaporator ends of the heat pipes unless otherwise noted. As an aside, the channels may be rectangular in cross section and may receive and thermally connect heat pipes of similar cross-sectional shape. The channels of the busbars, such as the phase busbar 524 and the V+ busbar 526, that receive the evaporator ends of the heat pipes may extend perpendicular to the longitudinal axis of the busbars.

[0213] In Figures 5a-1 and 5a-2, the evaporator ends of the heat pipes 522 are received within respective channels and thermally connected to the phase busbars 524 and the V+ busbar 526. Figure 5a-2 shows that each heat pipe 522 is electrically insulated from the phase busbars 524a-524c or the V+ busbar 526 by a thin layer of dielectric 536. In some embodiments, the dielectric layer should only cover the portions of the heat pipes 522 that are within the busbars, such as the phase busbars 524 and the V+ busbar 526. Thermal paste or grease can be used to fill air gaps on the outer surface of the dielectric 536 to enhance heat transfer to and from the busbars.

[0214] 5a-1 shows heat pipes 522 extending through phase busbars 524c and V+ busbar 526. In an alternative embodiment, the evaporative ends of heat pipes 522 are contained entirely within phase busbars 524a-524c and V+ busbar 526. To enhance heat dissipation, heat pipes 522 such as those in FIG. 5a-1 can be positioned closer to the surfaces of busbars such as phase busbar 524 and V+ busbar 526 that engage die substrate terminals 230.

[0215] The condenser end of the heat pipe 522 can be thermally and electrically connected to a metal heat fin, such as heat fin 20 of FIG. 5a-1, which can be cooled by a fan, such as fan 530. Although three flat metal heat fins are shown in the figures of this disclosure, it is understood that in alternative embodiments, one or more metal heat fins can be utilized. The metal heat fins need not be flat and can have shapes other than those shown in the figures. FIG. 5A-5 is a top view of the top heat fin 520. In one embodiment, the exterior surface of the heat pipe 522 is soldered to the cylindrical wall of an opening formed through a metal heat fin, such as heat fin 520.

[0216] The exterior surface of the evaporator end section of the heat pipe can interface with the surface of the channel of the heat sink, V+, V- or phase busbar in which the heat pipe is received. The exterior surface of the evaporator end of each heat pipe, such as heat pipe 522 of Figures 5a-1-5a-4, can be covered with a thin layer (e.g., 0.1-1.0 mm) 536 of a dielectric material (e.g., aluminum oxide, aluminum nitride, silicon nitride, etc.). The exterior dielectric layer (e.g., dielectric layer 536) can be the only dielectric in the thermal path between switch 304 and the liquid in the heat pipe. The exterior surface of a dielectric layer, such as dielectric layer 536, contacts the interior surface of the channel in which the heat pipe is received. Thermal paste or thermal grease can be added between the dielectric and the interior surface of the channel to facilitate heat transfer.

[0217] A dielectric layer such as dielectric layer 536 can be formed by spraying (e.g., flame spraying or plasma spraying) a dielectric material onto the outer surface of the heat pipe. Alternatively, a dielectric layer such as dielectric layer 536 can be formed by rolling the heat pipe in a dielectric material (e.g., TIM). A dielectric layer such as dielectric layer 536 can be formed by anodic oxidation or plasma electrolytic oxidation. A heat pipe can have multiple dielectric layers. For example, after forming an anodic oxidation layer on the outer surface of the heat pipe, a thin layer of a dielectric material (e.g., aluminum nitride) can be applied to the outer surface. Other processes for forming the dielectric layer or layers are also contemplated.

[0218] A dielectric layer, such as dielectric layer 536, can electrically insulate the heat pipe from a bus bar, heat sink, or other device. The dielectric material can have a dielectric strength in the range of up to 10 kV. The thickness of a dielectric layer, such as dielectric layer 536, is estimated to be 0.2 mm, although smaller or larger thicknesses are contemplated. The thickness of the dielectric layer and the material layer affect heat transfer.

[0219] The following table contains calculated values ​​of heat transfer W of the dielectric layer 536 for different dielectric materials and thicknesses. W is proportional to kA(T1-T2) / d, where k is the heat transfer coefficient, A is the area, T1-T2=70 is the temperature difference across the dielectric layer, and d is the thickness in micrometers. The calculated heat transfer W assumes a voltage of 4 kV across the dielectric. [Table 1]

[0220] In one embodiment, a plasma electrolytic oxidation or a Type II or Type III hardcoat anodization process can be used to grow a dielectric layer on substantially all of the inner and / or outer surface of the heat pipe, or only on certain portions of the inner and / or outer surface, Again, for ease of explanation, unless otherwise noted, no dielectric is formed on the inner surface of the heat pipe.

[0221] Type II anodization is a process that involves placing a piece of metal (e.g., aluminum) in an acid (e.g., sulfuric acid) bath. Type III hardcoat anodization is carried out under more severe processing conditions and results in a thicker dielectric layer.

[0222] Anodization is an electrolytic passivation process for forming or thickening a native oxide layer on the surface of a metal component. Anodization forms an oxide on the surface of the metal component as well as in the metal. The resulting oxide layer is an electrical insulator. The oxide layer is grown by passing a direct current through an electrolyte, typically sulfuric acid or chromic acid, in which all or part of the metal part (e.g., a heat pipe) is suspended and exposed. The metal part acts as the anode (positive electrode of the electrolytic cell). When a current is passed through the electrolyte, hydrogen is released at the cathode (negative electrode) and oxygen is released at the surface of the metal part, resulting in the build-up of oxide. The voltage required can be DC 1-300V. Higher voltages are usually required to thicken the oxide film formed by sulfuric acid and organic acids. The anodization current varies depending on the total area of ​​the metal part being anodized and typically ranges from 30-300A / m2. Conditions such as electrolyte concentration, acidity, solution temperature, and current can be controlled to allow for consistent oxide film formation. Harder and thicker oxide films tend to form with more concentrated solutions, lower temperatures, and higher voltages and currents.

[0223] The anodization process can be used to grow a dielectric layer oxide on the exterior surface of an aluminum heat pipe. The heat pipe acts as the anode in the process. An electric current is passed through an electrolyte bath solution in which some or most of the heat pipe is suspended, releasing hydrogen at the cathode and oxygen at the exterior surface of the heat pipe, creating an oxide buildup. The anodization process can be used to grow a dielectric layer, such as dielectric layer 536, only on the exterior surface of the evaporator end of an aluminum heat pipe, such as heat pipe 522, utilized in a rectifier or inverter, such as inverter 502i in FIG. 5a-1. The anodization process can be used to grow a dielectric layer only on the exterior surface of the condenser end of an aluminum heat pipe. Additionally, the anodization process can be used to grow a dielectric layer on substantially all of the exterior surface of an aluminum heat pipe.

[0224] Plasma electrolytic oxidation (PEO) is another electrochemical surface treatment process for growing insulating layers on metal heat pipes. It is similar to anodizing, but typically uses a higher electrical potential, which results in an electrical discharge and a resulting plasma that changes the structure of the oxide layer. This process can be used to grow thick (hundreds of micrometers), mostly crystalline oxide coatings on heat pipes made of metals such as aluminum, magnesium, and titanium. The coating chemically transforms the metal into an oxide, which grows both inward and outward from the original metal surface. Plasma electrolytic oxidation of aluminum requires the application of at least 200 V, which exceeds the breakdown potential of the locally growing oxide, and electrical discharges occur. These electrical discharges trigger local plasma reactions that transform the growing oxide under conditions of high temperature and pressure. The process includes melting, melt flow, resolidification, sintering, and densification of the growing oxide. One of the most important effects is that the oxide partially transforms from amorphous alumina to a harder crystalline form such as corundum (α-Al2O3). The heat pipe to be coated is immersed in an electrolyte bath, usually consisting of a dilute alkaline solution such as KOH. The heat pipe is electrically connected to one of the electrodes of an electrochemical cell, while the other electrode is usually made of an inert material such as stainless steel, and often consists of the wall of the bath itself. A potential of over 200 V can be applied between the two electrodes.

[0225] Anodization or plasma electrolytic oxidation can offer several advantages when compared to other methods for forming a dielectric layer such as dielectric layer 536 (e.g., spraying a dielectric on the exterior surface of a heat pipe). For example, anodization can provide a more mechanically robust dielectric layer. The exterior surface of the anodized dielectric layer is smoother compared to other methods, which can increase heat transfer between a heat sink or bus bar on one side of the dielectric and a heat pipe on the other side.

[0226] Regardless of how the dielectric layer is formed, the heat pipes can be electrically insulated from the busbars, heat sinks, or other devices while still transferring heat therebetween. In some embodiments, there is no dielectric between the heat pipes and the switch 304. FIGS. 5a-7 and 5a-8 are end and bottom views, respectively, of an alternative compact inverter 503i, such as the compact inverter 502i. FIG. 5a-9 shows electrically insulated heat fins on the top of the compact inverter 503i. With reference to FIG. 5a-8, the compact inverter 503i utilizes a heat pipe 522 that lacks a dielectric on its outer surface. With reference to FIGS. 5a-7 and 5a-9, the compact inverter system 503i includes electrically insulated metal fins 521-a through 521-c, and 521+. Fins 521-a to 521-c are electrically and thermally connected to heat pipes 522 embedded in phase bus bars 524a to 524c, respectively, and fin 521+ is electrically and thermally connected to heat pipe 522 embedded in V+ bus bar 526. As shown in FIG. 5A-9, the heat fins are electrically insulated from each other.

[0227] In general, the diameters of the heat pipes within a busbar or heat sink need not be equal. The number, location, and / or diameter of the heat pipes, including the dielectric layer, may depend on one or more variables. For example, the number, location, and / or diameter of the heat pipes may depend on the desired thermal capacitance of the busbar or heat sink in which the heat pipes are included. Or, the number, location, and / or diameter of the heat pipes may depend on the desired thermal resistance between the switch 304 and the fluid inside the heat pipe. Or, the number, location, and / or diameter may depend on optimizing the thermal capacitance based on the desired thermal resistance, or vice versa.

[0228] Although not shown in the various air-cooled inverter and rectifier figures of the present disclosure, terminals such as die substrate terminal 230 or die clip terminals such as die clip terminal 344 in FIG. 5a-1 can be electrically and / or thermally connected to corresponding pedestals on the heat sink or bus bars such as V+ bus bar 526 and phase bus bar 524. The pedestals can have a substantially flat surface that can be electrically and / or thermally connected (e.g., press-fit connected, soldered, sintered, etc.) to the die substrate terminals or die clip terminals. The pedestal surface can be substantially similar in size and shape to the die substrate or die clip terminals to which it is connected in order to maximize thermal and / or electrical conductivity therebetween. Although not required, a thin layer of thermally and / or electrically conductive material (e.g., grease or paste) can be applied between the bus bar pedestal surface and the die substrate terminals or die clip terminals to further enhance thermal and / or electrical conductivity when the two are pressed together. Clamps, bolts, and other such fasteners can be used to press the packaged switches or packaged half-bridges, and thus their die clip terminals or die substrate terminals, against the busbar pedestals.

[0229] The busbar pedestals may form an air gap between the plastic case of the packaged switch or packaged half bridge on one side and the V- busbar, heat sink, phase busbar, or V+ busbar on the other side. In some embodiments, a thermally conductive structure may fill each air gap to form a thermal path for heat generated, for example, by the gate driver 306, to be transferred to the heat sink or busbar. For example, a thermally conductive structure may be disposed adjacent to each pedestal and between the V+ busbar and each packaged switch or packaged half bridge. The thermally conductive structure transfers heat from the packaged switch or packaged half bridge to the V+ busbar. The height of the thermally conductive structure may be slightly less than the height of the pedestal in this embodiment. To accommodate the height difference and ensure a thermal connection between the busbar or heat sink and the corresponding packaged switch or packaged half bridge, a thermally conductive dielectric grease or similar TIM may be applied to the flat surface of each thermally conductive structure opposite the flat surface that engages the V+ busbar during construction. For example, heat generated by the gate driver 306 can be transferred to the V+ bus bar via thermal grease and a thermally conductive structure.

[0230] Phase busbars, such as phase busbars 524a-524c in FIG. 5A-2, can transfer current between devices. For example, phase busbars 524a-524c can conduct current between stator windings Wa-Wc and packaged switches or packaged half-bridges 250a-250c, respectively. Phase busbars, such as phase busbars 524a-524c, can be electrically and thermally connected to terminals, such as low-side die substrate terminals 230La-230Lc, respectively, in FIG. 5a-2. Phase busbars, such as phase busbars 524a-524c, can also be electrically connected to terminals, such as high-side die clip terminals 232Ha-232Hc, respectively, in FIG. 5a-1. These latter electrical connections can be made via metal straps internal or external to the packaged half-bridges. FIG. 5a-2 symbolically illustrates external metal straps 242. Metal straps can connect terminals such as die clip terminals 232Ha-232Hc directly to bus bars such as phase bus bars 524a-524c, respectively. Alternatively, external metal straps such as metal straps 242 shown in FIG. 2B-3 can connect terminals such as die clip terminals 232Ha-232Hc to other terminals such as side terminals 240 of lower die substrates 312La-312-Lc, respectively. In the exemplary compact inverter and rectifier system, the die substrate side terminals are not shown. Terminals such as low side die clip terminals 232La-232c can be electrically connected to a bus bar such as V-bus bar 528, which can be coupled to a device such as a V-battery terminal. V-bus bar 528 is symbolically shown in FIG. 5a-2. In FIG. 5a-1, V-bus bar 528 is disposed between rows of heat pipes 522 and has a rectangular cross section, although it is understood that other shapes are contemplated.

[0231] 5a-1-5a-4 include current symbols representing the current flow through the inverter system 502i at a certain instant in time. More specifically, FIG. 5a-2 shows the current flow through the a-phase activated high-side switch 304H, while the b- and c-phase low-side switches 304L are activated and conducting current to the V-battery terminal through the V-busbar 528. All other switches are shown as deactivated. What is important is that all die substrate terminals 230 are thermally and electrically connected to the V+busbar 526 or phase busbar 524.

[0232] One or more DC link capacitors may be electrically connected between a V+ bus bar, such as V+ bus bar 526, and a V- bus bar, such as V- bus bar 528. FIGS. 5a-3 and 5a-4 show DC link capacitors C electrically connected across inverter 502i. The DC link capacitors may take the form of thin wall capacitors, or the DC link capacitors may take the form of an array of ceramic capacitors coupled in parallel. Other types of capacitors, including electrolytic capacitors, may also be used. In yet another embodiment, each DC link capacitor may include multiple types of capacitors (e.g., thin wall and ceramic) coupled in parallel.

[0233] A DC link capacitor, such as DC link capacitor C, may fail during operation of the small inverter or small rectifier, causing an electrical short between the V+ and V- busbars. As a safety measure, fuses may be added in series between the DC link capacitors and the V+ or V- busbars. If an electrical short occurs between the DC link capacitors, the corresponding fuse may open to prevent additional current flow between the V+ and V- busbars. The DC link capacitors may become hot during operation of the power converter.

[0234] A DC link capacitor, such as capacitor C, may be thermally connected to one or more bus bars, such as V+ bus bar 526. The thermal connection allows for heat extraction from the DC link capacitor.

[0235] In some embodiments of a compact rectifier or compact inverter, such as compact inverters 400i-502i, the number and / or type of transistors in one switch, such as switch 304H, may differ from the number and / or type of transistors in another switch, such as switch 304L. For ease of explanation, all switches in an inverter or rectifier are presumed to have the same number and type of transistors unless otherwise noted.

[0236] The cases of the packaged half bridges 250a-250c may be thermally connected to the phase bus bars 524a-524c, respectively, and may be thermally connected to the V+ bus bar 526.

[0237] The inverter and rectifier may include a control PCB. Figures 5a-1, 5a-3 and 5a-4 show a control PCB 532 electrically connected to the packaged half-bridge 250 via a respective set 314 of connector leads. In one embodiment, a set of connector-leads, such as set 314, extend laterally from a packaged half-bridge case (see, e.g., Figure 3g-4) or packaged switch as described above. A set of connector-leads, such as set 314, may be received in a connector that is attached to the control PCB and may be electrically connected to traces thereon.

[0238] A microcontroller or other processor-based control unit, PMIC, and other devices can be connected to traces on a side of a control PCB, such as PCB 532, opposite the side adjacent to the packaged switches or packaged half-bridges. In another embodiment, devices (e.g., microcontrollers, PMICs, etc.) can be mounted on both sides of the control PCB. The microcontrollers, PMICs, and other devices can be electrically connected to packaged switches or packaged half-bridges, such as packaged half-bridge 250, through traces and metal vias formed on the control PCB, connectors, and connector leads, such as connector leads of set 314. The PMICs provide bias voltages to respective switch modules, such as switch module 300 of packaged half-bridge 250. The microcontroller provides PWM and other signals to the switch modules, such as switch module 300 of packaged half-bridge 250. The microcontroller can also receive signals, such as Vv, Vt, and Vi, from switch modules, such as switch module 300 of packaged half-bridge 250. The height of the exemplary compact inverter system 502i including the heat pipe 522 and the PCB 532 may be H2=100 mm. In some embodiments, the inverter or rectifier may include a control PCB and a power PCB, the latter of which is described below.

[0239] (air cooled rectifier 502r) Packaged switches and packaged half-bridges can be used in air-cooled rectifiers and other power converters. Figures 5a-10 and 5a-11 are semi-schematic diagrams of an example of an air-cooled rectifier system 502r using a packaged half-bridge 250. Figure 5a-10 shows the air-cooled rectifier system 502r from a bottom view. Figure 5a-11 shows the air-cooled rectifier system 502r from an end view. Air-cooled rectifiers such as rectifier 502r can be used in DC fast chargers, variable frequency drive controllers, and the like.

[0240] An air-cooled rectifier, such as rectifier 502r, may be electrically connected to an LCL filter, such as LCL filter 162 of FIG. 1c. At its opposite end, the LCL filter may be electrically connected to a three-phase AC power system, such as system 164 of FIG. 1c. For ease of illustration, the air-cooled rectifier of this disclosure does not show an LCL filter. Rather, the sources of power φa-φc of the three-phase AC power system are shown as inputs to the air-cooled rectifier. Thus, although the phase bus bars of the rectifier are shown electrically connected to the AC sources φa-φc, other devices, such as LCL filters, may be connected therebetween.

[0241] The rectifier system 502r and the inverter system 502i are substantially similar. There may be some differences. The microcontroller implemented on the control PCB 532 of the rectifier system 502r may be different from the microcontroller implemented on the control PCB 532 of the inverter system 502i, or the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB 532 of the rectifier system 502r may be different from the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB 532 of the inverter system 502i. The control PCB 532 of the rectifier 502r may also include a phase-locked loop (PLL) and other components for synchronizing the control of the switch 304 to the frequency (e.g., 60 Hertz) of the three-phase AC input voltage provided by the AC sources φa-φc. The control PCB 532 may also include components for power factor correction. It should be noted that the air-cooled inverter of the present disclosure may also include a PLL and other devices that allow it to operate inversely as a rectifier.

[0242] (Air-cooled inverter system 504i) Each phase of the example compact inverter system 502i of FIG. 5A-2 has one packaged half-bridge. The compact inverter system should not be so limited. The air-cooled inverter or rectifier can have two, three, four or more packaged switches or packaged half-bridges per phase. The power throughput of the air-cooled inverter or rectifier increases as the number of packaged switches or packaged half-bridges per phase increases.

[0243] 5b-1 to 5b-4 are semi-schematic diagrams of another air-cooled inverter system 504i as viewed from the end, bottom, left side, and right side. The small inverters 504i and 502i have something in common. The compact inverter system 504i may have the same height and length as the compact inverter system 502i, but the compact inverter system 504i is substantially wider.

[0244] Referring to FIG. 5b-2, the compact inverter system 504i has three phases ac, each phase ac includes a packaged half-bridge 250 as shown in FIG. 4a-1 or 4g-1. The packaged half-bridges 250a-250c are thermally and electrically connected to and disposed between the phase busbars 524-1a-524-1c and the V+ busbar 560, respectively. Each phase a-c of the compact inverter 504i also includes a packaged half-bridge 253 as shown in FIG. 4c-1 or 4h-1. The packaged half-bridges 253a-253c are thermally and electrically connected to and disposed between the V+ busbar 560 and the phase busbars 524-2a-524-2c, respectively. In one embodiment of the compact inverter 504i, the number and / or type of transistors of the switches 304 of the packaged half-bridge 250 may be different from the number and / or type of transistors of the switches 304 of the packaged half-bridge 253. For ease of explanation, all switches 304 of an inverter 504i are assumed to have the same number and type of transistors.

[0245] The ends of the heat pipes 522 are embedded in and thermally connected to the V+ busbar 560 and the phase busbar 524. Figures 5b-1 to 5b-5 show how the packaged half bridges 250 and 253 of each phase, the phase busbar 524, the heat pipes 522, the fins 521, and the V+ busbar 560 are arranged laterally relative to each other. The V+ busbar 560 can have a width W4 = 24 mm, a height of 27 mm, and a length of 100 mm.

[0246] The switches 304H of the packaged half bridges 250 and 253 are electrically and thermally connected to a V+ bus bar 560, which also functions as a heat sink. This connection can be made by pressing the die substrate terminals 230H to the V+ bus bar 560. Alternatively, the die substrate terminals 230H can be connected by sintering or soldering to the V+ bus bar 560. Other connection types are contemplated. The cases of the packaged half bridges 250 and 253 can be thermally connected to the V+ bus bar 560. The cases of the packaged half bridges 250 and 253 of each phase can also be thermally connected to the phase bus bars 524-1 and 524-2, respectively.

[0247] The switches 304L of the packaged half-bridges 250a-250c are electrically and thermally connected to the phase busbars 524-1a-524-1c, respectively. This connection can be made by pressing the die substrate terminals 230La1-230Lc1 against the surfaces of the phase busbars 524-1a-524-1c, respectively. Alternatively, the connection can be made by sintering or soldering the die substrate terminals 230La1-230Lc1 to the phase busbars 524-1a-524-1c, respectively. Other connection types are contemplated. The phase busbars 524-1a-524-1c are electrically isolated from each other and act as heat sinks for the switches 304L of the packaged half-bridges 250. The phase busbars 524-1a-524-1c are electrically connected to the stator windings Wa-Wc, respectively.

[0248] The switches 304L of the packaged half-bridges 253a-253c are electrically and thermally connected to the phase busbars 524-2a-524-2c, respectively. The connections can be made by pressing the die substrate terminals 230La2-230Lc2 against the surfaces of the phase busbars 524-2a-524-2c, respectively. Alternatively, the connections can be made by sintering or soldering the die substrate terminals 230La2-230Lc2 to the phase busbars 524-2a-524-2c, respectively. Other connection types are contemplated. The phase busbars 524-2a-524-2c are electrically isolated from each other and function as heat sinks for the switches 304L of the packaged half-bridges 253. The phase busbars 524-2a-524-2c are electrically connected to the stator windings Wa-Wc, respectively.

[0249] Fig. 5b-1 shows an end view of the air-cooled inverter device 504i. Fig. 5b-1 shows packaged half-bridge 250c sandwiched between phase busbar 524-1c and V+ busbar 560, and packaged half-bridge 253c sandwiched between phase busbar 524-2c and V+ busbar 560. Also shown in this view are heat pipes 522 embedded within phase busbar 524 and V+ busbar 560.

[0250] As seen in FIG. 5b-1, the evaporative ends of the heat pipes 522 are received in and thermally connected to respective channels formed in the phase busbar 524 and the V+ busbar 560. FIG. 5b-2 is a bottom view of the air-cooled inverter 504i. With continued reference to FIG. 5b-1, FIG. 5b-2 shows that each heat pipe 522 is electrically insulated from the phase busbar 524 or the V+ busbar 560 by a dielectric 536. FIG. 5b-2 shows the heat pipes 522 extending slightly through the phase busbar 524-1c, the phase busbar 524-2c, and the V+ busbar 526. To enhance heat dissipation, the heat pipes 522 are positioned closer to the surfaces of the phase busbars 524 and the V+ busbar 560 that engage the die substrate terminals 230.

[0251] The channels in the phase busbars 524 and V+ busbars 560 into which the ends of the heat pipes 522 are received are cylindrical and extend perpendicular to the long axis of the phase busbars 524 and V+ busbars 560. In an alternative embodiment, the channels may be rectangular in cross section to receive similarly shaped heat pipes. The condenser ends of the heat pipes 522 are thermally and electrically connected to metal heat fins 521, which may be wider than the metal fins 520 shown in FIG. 5a-1. The packaged half bridges 250 and 253 are not drawn to scale in the exemplary converter system of the present disclosure. Only two fans 530 are shown in the figure because the schematic half bridges 250 and 253 are drawn with dimensions disproportionate to the dimensions of the phase busbars 524 and V+ busbars 560 in the figure. The air-cooled inverter 504i may require only one fan 530 to cool the fins 521.

[0252] Returning to FIG. 5b-1 and FIG. 5b-2, the phase busbars 524-1a-524-1c can conduct current between the stator windings Wa-Wc, respectively, and the packaged half bridges 250a-250c, respectively. The phase busbars 524-1a-524-1c are electrically and thermally connected to the low side die substrate terminals 230La1-230Lc1, respectively. The phase busbars 524-1a-524-1c are also electrically connected to the high side die clip terminals 232Ha1-232Hc1, respectively. The high side die clip terminals 232Ha1-232Hc1 can be electrically connected to the phase busbars 524-1a-524-1c via respective metal straps inside or outside the packaged half bridges 250a-250. Metal straps can connect the die clip terminals 232Ha1-232Hc1 to the phase bus bars 524-1a-524-1c, respectively. Alternatively, and as shown, external metal straps can connect the die clip terminals 232Ha1-232Hc1 to small side terminals (not shown) of the low side die substrates 312La1-312Lc1, respectively. Metal straps 242 are symbolically indicated and referenced only in phase c.

[0253] The low-side die clip terminals 232La1-232c1 have a rectangular cross-section as shown in FIG. 5b-1 and are electrically connected to a V-bus bar 528-1 that is coupled to a V-battery terminal or other DC source.

[0254] The phase bus bars 524-2a to 524-2c can carry current between the stator windings Wa to Wc and the packaged half bridges 253a to 253c, respectively. The phase bus bars 524-2a to 524-2c are electrically and thermally connected to the low side die substrate terminals 230La2 to 230Lc2, respectively. The phase bus bars 524-2a to 524-2c are also electrically connected to the high side die clip terminals 232Ha2 to 232Hc2, respectively. The high side die clip terminals 232Ha2 to 232Hc2 can be electrically connected to the phase bus bars 524-2a to 524-2c via respective metal straps that are internal or external to the packaged half bridges 253a to 253. The metal straps can directly connect the die clip terminals 232Ha2 to 232Hc2 to the phase bus bars 524-2a to 524-2c, respectively. Alternatively, and as shown, external metal straps may connect the die clip terminals 232Ha2-232Hc2 to side terminals (not shown) of the lower die substrates 312La2-312Lc2, respectively.

[0255] The low-side die clip terminals 232La2 to 232c2 have a rectangular cross-section as shown in FIG. 5b-1 and are electrically connected to a V-bus bar 528-2 that is coupled to a V-battery terminal or other DC power source.

[0256] 5b-1 to 5b-5 show how the packaged half-bridges 250, packaged half-bridges 253, phase busbars 524, and V+ busbars 560 of each phase are arranged laterally relative to one another. The V-busbars 528 are symbolically shown in FIG. 5a-2. FIG. 5a-1 shows a V-busbar 528-1 arranged between a row of heat pipes 522, and a V-busbar 528-2 arranged between a pair of another row of heat pipes 522.

[0257] 5b-1 through 5b-5 include current symbols representing the current flow through the inverter system 504i at a certain instant in time. More specifically, FIG. 5b-2 shows the current flow through the a-phase activated high-side switch 304H, while the b- and c-phase low-side switches 304L are activated and conducting current to the V-battery terminal through the V-busbars 528-1 and 528-2. All other switches are deactivated in the figure. It is important to note that all die substrate terminals 230 are thermally and electrically connected to the V+busbar 560 or phase busbar 524. The DC link capacitor C can be electrically connected between the V+busbar 560 and the Vbusbar 528 at the end side of the inverter 504i as shown in FIG. 5b-3 and FIG. 5b-4. The capacitor C can also be thermally connected to the V+busbar 560.

[0258] 5b-1, 5b-3 and 5b-4 show a control PCB 562 electrically connected to the packaged half bridges 250 and 253 through respective sets of lead conductors 314-1 and 314-2 for each phase. A microcontroller or other processor-based control unit, PMIC and other devices can be mounted on traces on the side of the PCB 532 opposite the side adjacent to the packaged half bridges 250 and 253. The microcontroller and PMIC are electrically connected to the packaged half bridges 250 and 253 through traces and metal vias formed on the control PCB 562, connectors and set of conductor leads 314. The PMIC provides bias voltages to the switch modules of each of the packaged half bridges 250 and 253. The microcontroller provides PWM and other signals to the packaged half bridges 250 and 253, and the microcontroller receives feedback signals from the gate drivers 306, V_Sense, T_Sense and I_Sense circuits of the packaged half bridges. The height of the exemplary air-cooled inverter system 504i, including the heat pipes 522 and the PCB 532, may be H2=65 mm.

[0259] With continued reference to FIG. 5b-1, FIG. 5b-5 shows the PWM and reset signals received by phase a of the air-cooled inverter system 504i from the microcontroller of the control PCB 562. FIG. 5b-5 also shows the fault, Vi, and Vt outputs from phase a. Each packaged half-bridge 250 or 253 of a phase can be controlled by an independent set of PWM and reset signals generated by a microcontroller or other processor-based device. The microcontroller can provide the independent set of PWM and reset signals according to processor-executable instructions stored in memory. For example, the PWM signals provided by the microcontroller to the high side gate drivers of the packaged half bridges 250 and 253 in each phase can be intentionally staggered in time (e.g., the rising edge of PWM-H1a leads the rising edge of PWM-H2a and / or the falling edge of PWM-H1a leads the falling edge of PWM-H2a, or; the rising edge of PWM-H1a leads the rising edge of PWM-H2a and / or the falling edge of PWM-H2a leads the falling edge of PWM-H1a). In one embodiment, the PWM signals provided to the low-side gate drivers of the packaged half bridges 250 and 253 in a phase can be commonly controlled by a first high-side PWM signal from a microcontroller, and the PWM signals provided to the low-side gate drivers of the packaged half bridges 250 and 253 in each phase can be purposefully staggered in time (e.g., the rising edge of PWM-L1a leads the rising edge of PWM-L2a and / or the falling edge of PWM-L1a leads the falling edge of PWM-L2a, or; the rising edge of PWM-L1a leads the rising edge of PWM-L2a and / or the falling edge of PWM-L2a leads the falling edge of PWM-L1a). In an alternative embodiment, the high-side gate drivers of the packaged half bridges 250 and 253 in a phase can be commonly controlled by a first high-side PWM signal from a microcontroller, and the low-side gate drivers of the packaged half bridges 250 and 253 can be commonly controlled by a first low-side PWM signal from a microcontroller.In yet another embodiment, one of the packaged half-bridges 250 and 253 for each phase may be active while the other of the packaged half-bridges 250 and 253 for each phase may be inactive.

[0260] (air cooled rectifier 504r) FIG. 5b-6 is a semi-schematic diagram of an exemplary air-cooled rectifier system 504r as viewed from an end view. FIG. 5b-7 is a semi-schematic diagram of an exemplary air-cooled rectifier system 504r as viewed from a bottom view. The phase busbars 524 are electrically connected to the AC voltage sources φa-φc. The rectifier system 504r and the inverter system 504i are substantially similar. There are some differences. The microcontroller implemented on the control PCB of the rectifier system 504r may be different from the microcontroller implemented on the control PCB of the inverter system 504i, or the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB of the rectifier system 504r may be different from the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB of the inverter system 504i. The control PCB of rectifier 504r may also include a phase-locked loop (PLL) and other components for synchronizing the control of switch 304 to the frequency (e.g., 60 Hertz) of the three-phase AC input voltage provided by AC source φa-φc.

[0261] (Air-cooled inverter 506i) 5c-1-5c-4 are semi-schematic diagrams of an exemplary air-cooled inverter system 506i from end, bottom, left, and right views, respectively. Air-cooled inverters 506i and 502i have in common: air-cooled inverter system 506i may have the same height and width as air-cooled inverter system 502i, while air-cooled inverter system 504i may have twice the length.

[0262] Referring to Fig. 5c-2, which is a bottom view, the air-cooled inverter system 506i utilizes a packaged half-bridge 250 as shown in Fig. 4g-1. Alternatively, the air-cooled inverter system 506i can utilize a packaged half-bridge 253 as shown in Fig. 4c-1.

[0263] With continued reference to the bottom view of FIG. 5c-2, air-cooled inverter system 506i has three phases designated ac. Phase a includes packaged half bridges 250a1 and 250a2 disposed between phase bus bar 566a and V+ bus bar 564. Phase b includes packaged half bridges 250b1 and 250b2 disposed between phase bus bar 566b and V+ bus bar 564. Phase c includes packaged half bridges 250c1 and 250c2 disposed between phase bus bar 566c and V+ bus bar 564. FIGS. 5c-1 through 5c-4 show the relative positions of packaged half bridges 250, phase bus bar 560, heat pipes 522, fins 523, V- bus bar 570, and V+ bus bar 564 relative to one another.

[0264] The switches 304H of all packaged half-bridges 250 are electrically and thermally connected to a V+ bus bar 564, which also serves as a heat sink. The connection can be made by pressing the die substrate terminals 230H against the surface of the V+ bus bar 564. The connection can also be made by sintering or soldering the die substrate terminals 230H to the V+ bus bar 564.

[0265] The switch 304L of the packaged half bridge 250a is electrically and thermally connected to a phase bus bar 566a, which is electrically connected to the stator winding Wa. The connection can be made by pressing the die substrate terminal 230L against the surface of the phase bus bar 566a. The connection can also be made by sintering or soldering the die substrate terminal 230L to the phase bus bar 566a.

[0266] The switch 304L of the packaged half-bridge 250b is electrically and thermally connected to the phase bus bar 566b, which is electrically connected to the stator winding Wb. The connection can be made by pressing the die substrate terminal 230L against the surface of the phase bus bar 566b. The connection can also be made by sintering or soldering the die substrate terminal 230L to the phase bus bar 566b.

[0267] The switch 304L of the packaged half-bridge 250c is electrically and thermally connected to the phase busbar 566c, which is electrically connected to the stator winding Wc. The connection can be made by pressing the die substrate terminal 230L against the surface of the phase busbar 566c. The connection can also be made by sintering or soldering the die substrate terminal 230L to the phase busbar 566c.

[0268] Phase bus bars 566a-566c are electrically insulated from one another and function as heat sinks for their respective switches 304L.

[0269] FIG. 5c-1 is an end view of the air-cooled inverter system 506i. Similar to FIG. 5c-2, FIG. 5c-1 shows the packaged half-bridge 250c1 sandwiched between the phase busbar 566c and the V+ busbar 564. Also shown in this view are metal heat pipes 522 embedded in the phase busbar 566 and the V+ busbar 564. The heat pipes 522 extract heat from the busbars to cool the switches 304 thermally connected thereto. In FIGS. 5c-1 and 5c-2, the evaporative ends of the heat pipes 522 are received within and thermally connected to respective channels formed in the phase busbar 566 and the V+ busbar 564. FIG. 5c-2 shows the heat pipes 522s electrically insulated from the phase busbar 566 or the V+ busbar 564 by a thin layer of dielectric 536. FIG. 5c-1 shows the heat pipe 522 extending slightly through the phase busbar 566c1 and the V+ busbar 564.

[0270] The channels in the phase busbar 564 and V+ busbar 566 into which the evaporator side terminals of the heat pipes 522 are received are cylindrical and run perpendicular to the long axis of the busbars. The condenser ends of the heat pipes 522 are thermally and electrically connected to metallic heat fins 523, which are cooled by a fan 530. Although three flat metallic heat fins 523 are shown in the figures of this disclosure, it will be understood that in alternative embodiments, one or more metallic heat fins 523 may be utilized.

[0271] Returning to Figs. 5c-1 and 5c-2, the phase bus bar 566a transfers current between the stator winding Wa and the packaged half bridges 250a1 and 250a2. The phase bus bar 566a is electrically and thermally connected to the low side die substrate terminals 230La1 and 230La2. The phase bus bar 566a is also electrically connected to the high side die clip terminals 232Ha1 and 232Ha2. These electrical connections can be made via respective metal straps that are internal or external to the packaged half bridges 250a1 and 250a2. The metal straps can directly connect the die clip terminals 232Ha1 and 232Ha2, respectively, to the phase bus bar 566a. Alternatively, as shown in phase a, respective external metal straps connect the die clip terminals 232Ha1 and 232Ha2 to side terminals (not shown) of the lower side die substrates 312La1 and 312La2, respectively. The low side die clip terminals 232La1 and 232La2 are electrically connected to a V-bus bar 570, which is coupled to the V-battery terminal. The V-bus bar 570 is symbolically shown in FIG. 5a-2. In FIG. 5a-1, the V-bus bar 570 is disposed between the rows of heat pipes 522.

[0272] The phase bus bar 566b is electrically and thermally connected to the low side die substrate terminals 230Lb1 and 230b2. The phase bus bar 566b is also electrically connected to the high side die clip terminals 232Hb1 and 232Hb2. These electrical connections can be made via respective metal straps that are internal or external to the packaged half bridges 250b1 and 250b2. The metal straps can directly connect the die clip terminals 232Hb1 and 232Hb2, respectively, to the phase bus bar 566b. Alternatively, as shown in phase b, respective external metal straps connect the die clip terminals 232Hb1 and 232Hb2 to side terminals (not shown) of the lower die substrates 312Lb1 and 312Lb2, respectively. The low side die clip terminals 232Lb1 and 232Lb2 are electrically connected to the V bus bar 570.

[0273] The phase bus bar 566c is electrically and thermally connected to the low side die substrate terminals 230Lc1 and 230c2. The phase bus bar 566c is also electrically connected to the high side die clip terminals 232Hc1 and 232Hc2. These electrical connections can be made via respective metal straps that are internal or external to the packaged half bridges 250c1 and 250c2. The metal straps can directly connect the die clip terminals 232Hc1 and 232Hc2, respectively, to the phase bus bar 566c. Alternatively, and as shown, respective external metal straps connect the die clip terminals 232Hc1 and 232Hc2 to side terminals (not shown) of the lower die substrates 312Lc1 and 312Lc2, respectively. The low side die clip terminals 232Lc1 and 232Lc2 are electrically connected to the V bus bar 570.

[0274] 5c-1 to 5c-4 include current symbols representing the current flow through the inverter system 506i at a given moment. More specifically, FIG. 5c-2 shows the current flow through the a-phase activated high-side switch 304H, while the b- and c-phase low-side switches 304L are activated and conduct current to the V-battery terminal through the V-busbar 570, which is shown as a rectangular cross-section in FIG. 5c-1. All other switches are shown as inactive. It is important to note that all die substrate terminals 230 are thermally and electrically connected to the V+busbar 564 or phase busbar 566. The DC link capacitor C is electrically connected between the V+busbar 564 and the V-busbar 570 on the front and back sides, as shown in FIG. 5c-3 and FIG. 5c-4. The capacitor C can also be thermally connected to the busbar V+busbar 564.

[0275] 5c-1, 5c-3, and 5c-4 show a control PCB 568 electrically connected to the packaged half bridge 250 via a respective set of connector leads 314. A microcontroller or other processor-based control unit, PMIC, and other devices can be mounted on traces on the side of the PCB 568 opposite the side adjacent to the packaged half bridge 250. The microcontroller and PMIC are electrically connected to the packaged half bridge 250 via a set of connector leads, traces, and metal vias formed on the control PCB 232. The PMIC provides bias voltages to the respective switch modules of the packaged half bridge 250. The microcontroller provides PWM and other signals to the packaged half bridge 250. Signals and power voltages can be transmitted between the packaged half bridge 250 and the microcontroller and PMIC via the set of connector leads, PCB traces, and metal vias 314.

[0276] (Air-cooled inverter 508i) Air-cooled inverter systems 502i-506i and air-cooled rectifier systems 502r-506r mainly include switches that are cooled on one side. Figures 5d-1-5d-4 are semi-schematic diagrams of an example of an air-cooled inverter system 508i having switches that are cooled on both sides. Air-cooled inverter system 508i may have the same height and length as air-cooled inverter system 502i, but air-cooled inverter system 508i may be wider.

[0277] 5d-1 to 5d-4 are diagrams showing the air-cooled inverter device 508i as seen from the end, bottom, left side, and right side, respectively. Referring to the bottom view of FIG. 5d-2, the air-cooled inverter system 508i uses the packaged switch 211 shown in FIG. 3e-1 and the packaged switch 209 shown in FIG. 3f-1. The packaged switch 211 can use the switch module 305 shown in FIG. 3k-1 or the switch module 319 shown in FIG. 3m-1, and the packaged switch 209 can use the switch module 307 shown in FIG. 3l-1 or the switch module 321 shown in FIG. 3n-1.

[0278] With continued reference to FIG. 5d-2, the air-cooled inverter system 508i has three phases a-c each including a packaged switch 211a-211c disposed between a heat sink 572a-572c, respectively, and a V+ busbar 576. The ac phases also include packaged switches 209a-209c disposed between a heat sink 572a-572c, respectively, and a V-busbar 578, as shown. The V-busbar 578 also functions as a heat sink with a heat pipe 522 embedded therein. FIGS. 5d-1-5d-4 illustrate the lateral positioning of the packaged switches 211 and 209, heat sink 572, V+ busbar, heat pipe 522, heat fins 525, and V-busbar 578 relative to one another in each phase.

[0279] The switches 304H of the packaged switches 211a-211c are electrically and thermally connected to the V+ bus bar 576 and the heat sinks 572a-572c, respectively. This connection can be made by pressing the die substrate terminals 230H against the surface of the V+ bus bar 576 while simultaneously pressing the die clip terminals 344Ha-344Hc against the surfaces of the heat sinks 572a-572c, respectively. Alternatively, the connections can be made by sintering or soldering the die substrate terminals 230H and the die clip terminals 344H to the V+ bus bar 576 and the heat sinks 572, respectively. Other types of connections are contemplated.

[0280] The switches 304L of the packaged switches 209a-209c are electrically and thermally connected to the V-bus bar 578 and the heat sinks 572a-572c. This connection can be made by pressing the die clip terminals 230L against the V-bus bar 578 while simultaneously pressing the die substrate terminals 344La-344Lc against the heat sinks 572a-572c, respectively. Alternatively, the connections can be made by sintering or soldering the die substrate terminals 230L and the die clip terminals 344L to the V-bus bar 578 and the heat sinks 572, respectively. Other types of connections are contemplated.

[0281] Fig. 5d-1 is an end view of air-cooled inverter system 508i. Similar to Fig. 5d-2, Fig. 5d-1 shows packaged switch 211Hc sandwiched between heat sink 572c and V+ busbar 576, and packaged switch 209c sandwiched between heat sink 572c and V- busbar 578. Also shown in this view are heat pipes 522 embedded within heat sink 572c, V+ busbar 576, and V- busbar 578.

[0282] As seen in FIG. 5d-1, the evaporative ends of the heat pipes 522 are received in and thermally connected to respective channels formed in the heat sink 572, the V+ bus bar 576, and the V- bus bar 578. FIG. 5d-2 is a bottom view of the air-cooled inverter 508i. With continued reference to FIG. 5d-1, FIG. 5d-2 shows that each heat pipe 522 is electrically insulated from the heat sink 572, the V+ bus bar 579, or the V- bus bar 578 by a dielectric material 536. FIG. 5d-2 shows that the heat pipes 522 extend slightly through the heat sink 572, the V+ bus bar 579, and the V- bus bar 578. To enhance heat dissipation, the heat pipes 522 are positioned closer to the surfaces of the heat sink 572, the V+ bus bar 579, and the V- bus bar 578 that engage the die substrate terminals 230 or the die clip terminals 344.

[0283] The channels in the heat sink 572, V+ busbar 579 or V- busbar 578 in which the evaporator ends of the heat pipes 522 are received are cylindrical and extend perpendicular to the long axis of the heat sink 572, V+ busbar 579 or V- busbar 578. In alternative embodiments, the channels may be rectangular in cross section to accommodate similarly shaped heat pipes. The condenser ends of the heat pipes 522 are thermally and electrically connected to metal heat fins 525, which may be slightly larger than the metal fins 520 shown in FIG. 5a-1. The packaged switches 211 and 209 are not drawn to scale. Only two fans 530 are shown in the figure because the packaged switches 211 and 209, which are shown in schematic form, are drawn with dimensions disproportionate to the dimensions of the heat sink 572, V+ busbar 579 or V- busbar 578 in the figure. When building an air-cooled inverter 508i, only one fan 530 may be required to cool the fins 525.

[0284] Returning to Figs. 5d-1 and 5d-2, when activated, switch 304H can conduct current from V+ busbar 576 to each of stator windings Wa-Wc through die clip terminals 232a-232c, and when activated, switch 304L can conduct current received from each of stator windings Wa-Wc through die clip terminals 232La-232Lc to V- busbar 578. Heat sinks 572a-572c are electrically and thermally connected to die clip terminals 344Ha-344Hc and die clip terminals 344La-344Lc, respectively. Die substrate terminal 230L is electrically and thermally connected to V- busbar 578, which is electrically coupled to the negative terminal of a battery or other DC power source. Die substrate terminal 230H is electrically and thermally connected to a V+ bus bar 576, which is electrically coupled to the positive terminal of a battery or other DC power source.

[0285] 5d-1-5d-4 include current symbols representing the current flow through the inverter system 508i at a given moment. More specifically, FIG. 5d-2 shows the current flow through the a-phase activated high-side switch 304H, while the b- and c-phase low-side switches 304L are activated and conducting current to the V-battery terminal through the V-busbar 578. All other switches are deactivated in the figure. Importantly, all die substrate terminals 230 and all die clip terminals 344 are thermally and electrically connected to the V+ busbar 576, the V-busbar 578, or the heat sink 572. Although not shown, one or more DC link capacitors C may be electrically connected between the V+ busbar 576 and the V-busbar 578. The capacitors C may also be thermally connected to the V+ busbar 576 and / or the V-busbar 578.

[0286] 5d-1, 5d-3 and 5d-4 show the control PCB 574 electrically connected to the packaged switches 211 and 209 through respective sets of connector leads 314. A microcontroller or other processor-based control unit, PMIC and other devices can be mounted on traces on the side of the PCB 574 opposite to the side adjacent to the packaged switches 211 and 209. The microcontroller and PMIC are electrically connected to the packaged switches through traces and metal vias, connectors and sets of connector leads 314 formed on the control PCB 574. The PMIC provides bias voltages to the respective packaged switches 211 and 209. The microcontroller provides PWM and other signals to the packaged switches 211 and 209. The height of the exemplary air-cooled inverter system 508i including the heat pipe 522 and the PCB 574 can be H2=65mm.

[0287] (air cooled rectifier 508r) FIG. 5d-5 is a semi-schematic diagram of an exemplary air-cooled rectifier system 508r as viewed from an end. FIG. 5d-6 is a semi-schematic diagram of the air-cooled rectifier 508r as viewed from a bottom. The die clip terminals 232 are electrically connected to the AC power sources φa-φc. The rectifier system 508r and the inverter system 508i are substantially similar. There are some differences. The microcontroller implemented on the control PCB of the rectifier system 508r may be different from the microcontroller implemented on the control PCB of the inverter system 508i, or the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB of the rectifier system 508r may be different from the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB of the inverter system 508i. The control PCB of rectifier 508r may also include a phase-locked loop (PLL) and other components for synchronizing the control of switch 304 to the frequency (e.g., 60 Hertz) of the three-phase AC input voltage provided by AC source φa-φc.

[0288] (Air-cooled full-bridge inverter 510) Air-cooled inverter systems 502i-508i are examples of three-phase air-cooled inverter systems that can be used in EVs. Figures 5e-1-5e-4 are semi-schematic diagrams of an exemplary air-cooled full-bridge inverter system 510i from end, bottom, left side, right side, and top views, respectively. Air-cooled full-bridge inverter device 504i may have the same height and width as air-cooled inverter device 502i, but full-bridge inverter device 504i has a shorter length.

[0289] With continued reference to FIG. 5e-2, the air-cooled inverter system 510 has two phases designated a and b. Phases a and b include packaged half-bridges 250a and 250b, respectively, that are connected to and disposed between phase bus bars 524a and 524b, respectively, and a V+ bus bar 584, as shown. FIGS. 5a-1 through 5a-4 show how each phase's packaged half-bridges 250, phase bus bars 524, heat pipes 522, heat fins 527, and V+ bus bar 584 are positioned relative to one another.

[0290] The switch 304H is electrically and thermally connected to a V+ busbar 584, which also functions as a heat sink. The connection can be made by pressing the die substrate terminal 230H against the surface of the V+ busbar 584. The connection can also be made by sintering or soldering the die substrate terminal 230H to the V+ busbar 584. The switch 304L of the packaged half-bridges 250a and 250b is electrically and thermally connected to the phase busbars 524a and 524b, respectively, which are electrically connected to the respective terminals of a load (e.g., a home electrical panel, which is connected to a washing machine, refrigerator, or other devices requiring single-phase AC power), as shown in FIG. 5e2. The connection can be made by pressing the die substrate terminal 230L against the surface of the respective phase busbars 524a and 524b. The connection can also be made by sintering or soldering the die substrate terminal 230L to the respective phase busbars 524a and 524b. The phase bus bars 524a and 524b are electrically isolated from each other and act as a heat sink for each switch 304L. A filter can be added to smooth the output of the air-cooled inverter 510 before delivering it to the load.

[0291] FIG. 5e-1 is an end view of the air-cooled inverter system 510. Similar to FIG. 5e-2, FIG. 5e-1 shows the packaged half bridge 250b sandwiched between the phase bus bar 524b and the V+ bus bar 584. Also shown in this view is a metal heat pipe 522 embedded in the phase bus bar 524 and the V+ bus bar 584. The cases of the packaged half bridges 250a and 250b can be thermally connected to the phase bus bars 524a and 524c, respectively. The cases of the packaged half bridges 250a and 250b can be thermally connected to the V+ bus bar 584.

[0292] In Figures 5e-1 and 5e-2, the evaporative ends of the heat pipes 522 are received within and thermally connected to respective channels formed in the phase bus bars 524 and the V+ bus bar 584. Figure 5e-2 shows that each heat pipe 522 is electrically insulated from the phase bus bars 524a and 524b or the V+ bus bar 584 by a thin layer of dielectric 536. Figure 5e-1 shows the heat pipes 522 extending slightly through the phase bus bars 524b and the V+ bus bar 526. To enhance heat dissipation, the heat pipes 522 are positioned closer to the surfaces of the phase bus bars 524 and the V+ bus bar 584 that engage the die substrate terminals 230.

[0293] The channels in the phase busbar 524 and V+ busbar 584 in which the evaporator ends of the heat pipes 522 are received are cylindrical and extend perpendicular to the long axis of the phase busbar 524 and V+ busbar 584. The condenser ends of the heat pipes 522 are thermally and electrically connected to metal heat fins 527, which are cooled by a fan 530. Although three flat metal heat fins 527 are shown in the figures of this disclosure, it is understood that in alternative embodiments, one or more metal heat fins 527 may be utilized. The metal heat fins need not be flat and may take shapes other than those shown in the figures. In one embodiment, the exterior surface of the cylindrical heat pipes 522 is soldered to the cylindrical wall of the openings formed through the metal heat fins 527.

[0294] Returning to FIGS. 5e-1 and 5e-2, the phase bus bars 524a and 524b conduct current between the terminals of the load and the packaged half bridges 250a and 250b. The phase bus bars 524a and 524b are electrically and thermally connected to the low side die substrate terminals 230La and 230Lb, respectively. The phase bus bars 524a and 524b are also electrically connected to the high side die clip terminals 232Ha and 232Hb, respectively. These electrical connections can be made via metal straps that are internal or external to the packaged half bridges 250a and 250b. The metal straps can directly connect the die clip terminals 232Ha and 232Hb to the phase bus bars 524a and 524c, respectively. Alternatively, and as shown, external metal straps connect the die clip terminals 232Ha and 232H to side terminals (not shown) of the low side die substrates 312La and 312Lb, respectively. The low side die clip terminals 232La and 232Lb are electrically connected to a V-bus bar 586, which is coupled to a V-battery terminal or other DC source (e.g., the solar panel array of a photovoltaic module). The V-bus bar 586 is symbolically shown in FIG. 5e-2. In FIG. 5e-1, the V-bus bar 528 is disposed between the thermal rows of the heat pipes 522.

[0295] FIG. 5e-2 includes current symbols that represent the current flow through the inverter system 510 at a given moment. More specifically, FIG. 5e-2 shows the current flow through the a-phase activated high-side switch 304H, and the b-phase low-side switch 304L is activated and conducting current to the V-battery terminal through the V-busbar 586. The other two switches are deactivated in the figure. It is important to note that all die substrate terminals 230 are thermally and electrically connected to the V+busbar 584 or phase busbar 524. The DC link capacitor C is electrically connected between the V+busbar 584 and the Vbusbar 586 on the front and back sides as shown in FIG. 5e-3 and FIG. 5e-4. The capacitor C can be thermally connected to the busbar V+busbar 584.

[0296] 5e-1, 5e-3 and 5e-4 show the control PCB 582 electrically connected to the packaged half bridge 250 through the respective set of connector-leads 314. A microcontroller or other processor-based control unit, PMIC and other devices can be mounted on traces on the side of the PCB 582 opposite to the side adjacent to the packaged half bridge 250. The microcontroller and PMIC are electrically connected to the packaged half bridge 250 through traces and metal vias formed on the control PCB 582, connectors and set of connector leads 314. The PMIC provides bias voltages to the respective switch modules of the packaged half bridge 250. The microcontroller provides PWM and other signals to the packaged half bridge 250. The height of the exemplary air-cooled inverter system 510 including the heat pipes 522 and the PCB 582 can be H2=65 mm.

[0297] (Air-cooled rectifier 510r) FIG. 5e-5 is a semi-schematic diagram of an exemplary air-cooled rectifier system 510r from an end view. FIG. 5e-6 is a semi-schematic diagram of an exemplary air-cooled rectifier system 510r from a bottom view. The rectifier system 510r and the inverter system 510i are substantially similar. There are some differences. The die clip terminals 232H are electrically connected to the AC power source via the respective phase bus bars 524 as shown. The microcontroller implemented on the control PCB of the rectifier system 510r may be different from the microcontroller implemented on the control PCB of the inverter system 510i, or the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB of the rectifier system 510r may be different from the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB of the inverter system 510i. The control PCB of the rectifier 510r may also include a phase-locked loop (PLL) and other components for synchronizing the control of the switch 304 to the frequency of the AC input voltage.

[0298] (Air-cooled inverter 514i) Air-cooled inverters 502i-510i and air-cooled rectifiers 502r-510r utilize packaged switches or packaged half-bridges with switch modules that include switch controllers and other components. Figures 5f-1 and 5f-2 are semi-schematic diagrams illustrating related aspects of another air-cooled inverter system 514i utilizing packaged switches such as packaged switch 247d that lack a switch controller. Figures 5f-1 and 5f-2 show the air-cooled inverter system 514i from end and bottom views, respectively.

[0299] Referring to FIG. 5f-2, inverter system 514i includes three ac phases. Each ac phase includes two as shown in FIG. 2e-1 connected to phase busbars 572T, the combination of which is sandwiched between V+ busbar 576T and V- busbar 578T. This figure shows the vertical positioning of packaged switch 247d, V+ busbar 576T, phase busbar 572T, and V- busbar 578T relative to each other. Ends of heat pipes 522 are embedded in and thermally connected to V+ busbar 576T, V- busbar 578T, and phase busbar 572T. Phase busbars 572T are each 8 mm in length in one embodiment. 2 9 mm, and 35 mm. V+ busbar 576T and V- busbar 578T, in one embodiment, can have a height, width, and length of 8 mm, 2 It can have a height, width and length of 9mm and 100mm. Packaged switch 247d utilizes switch module 376 of Figure 3p-7. Bridge 368 is not shown in Figure 5f-1 or 5f-2.

[0300] The air-cooled inverter system 514i allows for dual sided cooling of the packaged switch 247d switch 304. The case of the packaged switch 247d can be thermally connected to the V+ busbar 576T and the phase busbar 572T, or can be thermally connected to the phase busbar 572T and the V- busbar 578T.

[0301] The phase bus bars 572Ta to 572Tc are electrically connected to the stator windings Wa to Wc, respectively. In FIG. 5f-2, the phase bus bars 572Ta to 572Tc are electrically insulated from each other. The die substrate terminals 230 of the packaged switches 247dH of each phase are connected to the corresponding flat surfaces of the V+ bus bar 576T by press-fitting, soldering, sintering, or other means, and establish thermal and electrical connectivity therebetween. The die clip terminals 344 of the packaged switches 247dHa to 247dHc are connected to the corresponding flat surfaces of the phase bus bars 572Ta to 572c by press-fitting, soldering, sintering, or other means, and establish thermal and electrical connectivity therebetween. The die substrate terminals 230 of the packaged switches 247dLa-247dLc are connected to corresponding flat surfaces of the phase bus bars 572Ta-572Tc, respectively, by press-fitting, soldering, sintering, or other means to establish thermal and electrical connectivity therebetween. The die clip terminals 344 of the packaged switches 247dL are electrically connected to the V- bus bar 578T. Each of the bus bars 576T, 578T, and 572T includes a channel that holds a respective heat pipe 522. One or more DC link capacitors C may be electrically connected in parallel between the V+ bus bar 576T and the V- bus bar 578T. In one embodiment, the DC link capacitors C may also be thermally connected to the V+ bus bar 576T and / or the V- bus bar 578T.

[0302] Figures 5f-1 and 5f-2 include current symbols that represent the current flow through inverter system 514i at certain moments in time. More specifically, Figure 5f-1 shows the current flow through inverter system 514i when a-phase switch 247dH is activated to conduct current from V+ busbar 576T and b- and c-phase switches 247dL are activated to conduct current to V- via V- busbar 578T. All other switches are deactivated.

[0303] Returning to FIG. 5f-1, the inverter 514i includes a control PCB 577 with opposing sides and a power PCB 575 with opposing sides. Components can be mounted on traces on each side of the PCBs 575 and 577. FIG. 5f-1 shows the MCU and the PMIC for each packaged switch 247d of the c-phase, all mounted on the side of the control PCB 577 facing away from the packaged switch 247d. Additional components can be mounted on traces on this side of the PCB 577 and on the side facing the packaged switch 247d. Vias can connect the traces on the other side of the control PCB 577. FIG. 5f-1 also shows the gate driver 306 and V_Sense circuit for each packaged switch 247d of the c-phase attached to traces on the other side of the power PCB 575. Additional components, such as connectors, diodes, resistors, etc., can be mounted on traces on both sides of the power PCB 575. The vias can connect traces on opposite sides of the power PCB 575.

[0304] The control PCB 577 is electrically connected to the power PCB 575 via the respective set of connector-leads 464. FIG. 5f-2 shows only the connector leads 602 of the respective set 464 of the c-phase connecting the control PCB 577 to the power PCB 575. The control PCB 577 sends signals (e.g., PWM signals, reset) to and receives signals (e.g., fault, Vv, etc.) from the power PCB 575 through respective conductive paths including the PCB traces and connector leads of the set 464. The control PCB 577 also provides a power supply bias voltage to the power PCB 575 through respective conductive paths including the PCB traces and connector leads in the set 464.

[0305] Although not shown, the ends of each set of connector-leads 464 may be received in respective connectors attached to traces on each side of opposing PCBs 575 and 577. Although not shown, additional connectors may be attached to traces on the side of power PCB 575 that faces packaged switch 247d. These additional connectors receive the ends of respective sets of connector-leads 288. Only each set of connector-leads 288g for phase c is shown in FIG. 5f-1.

[0306] (air cooled rectifier 514r) FIG. 5f-3 is a semi-schematic bottom view of an exemplary air-cooled rectifier system 514r. FIG. 5f-4 is a semi-schematic end view of the air-cooled rectifier system 514r. The phase bus bars 572Ta-572Tc are electrically connected to the AC power sources φa-φc. The rectifier system 514r and the inverter system 514i are substantially similar. The microcontroller implemented on the control PCB of the rectifier system 514r may be different from the microcontroller implemented on the control PCB 577 of the inverter system 514i, or the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB 577 of the rectifier system 514r may be different from the CPU executable instructions stored in the memory of the microcontroller implemented on the control PCB 577 of the inverter system 514i. The control PCB 577 of the rectifier 514r may also include a phase-locked loop (PLL) and other components for synchronizing the control of the switch 304 to the frequency (e.g., 60 Hertz) of the three-phase AC input voltage provided by the AC sources φa-φc.

[0307] The exemplary air-cooled rectifiers discussed above utilize packaged switches or packaged half-bridges. These air-cooled rectifiers are examples of active devices. Passive air-cooled rectifiers are also contemplated. Passive rectifiers do not use switches. Rather, passive rectifiers may utilize diodes. The air-cooled rectifier 514r shown in FIGS. 5f-3 and 5f-4 can be converted to a passive rectifier by replacing the packaged switch 347d with a diode (e.g., a trench diode). FIG. 5f-5 illustrates an example in which the packaged switch 247d of FIG. 5f-4 is replaced with a respective diode D. The anode of the diode DL is electrically and thermally connected to the V- busbar 578T, and the cathode of the diode DL is electrically and thermally connected to the respective phase bar 572T. The cathode of the diode DH is electrically and thermally connected to the V+ busbar 576T, and the anode of the diode DH is electrically and thermally connected to each phase bar 572T. The anodes and cathodes may be directly sintered, soldered, or otherwise connected to their respective bus bars. Alternatively, each of the diodes D may be connected (e.g., sintered) to and between a pair of metal conductors, such as die substrates, each having opposing flat surfaces. The sandwiched combination of the diodes and connected metal conductors may be directly sintered, soldered, or otherwise connected to adjacent bus bars. This method results in a larger gap between adjacent bus bars connecting the diodes. The air-cooled rectifier below is an active device.

[0308] (Air-cooled full-bridge inverter 514sf) The single-phase inverter may also use a packaged switch 247d as shown in Figures 2f-1 and 5f-2. Figures 5f-6 and 5f-7 are semi-schematic diagrams illustrating related aspects of another air-cooled inverter system 514sf utilizing a packaged switch such as packaged switch 247d lacking a switch controller. Figures 5f-6 and 5f-7 show an air-cooled inverter system 514i from end and bottom views, respectively.

[0309] Referring to FIG. 5f-7, inverter system 514sf includes two phases a and b. Each of phases a and b includes two packaged switches 247d as shown in FIG. 2e-1 connected to a phase busbar 572T, the combination of which is sandwiched between V+ busbar 576Tsf and V- busbar 578Tsf. The figure shows the vertical positioning of packaged switches 247d, V+ busbar 576Tsf, phase busbar 572T, and V- busbar 578Tsf relative to each other. The ends of heat pipes 522 are embedded in and thermally connected to V+ busbar 576Tsf, V- busbar 578T, and phase busbar 572Tsf. V+ busbar 576Tsf and V- busbar 578Tsf are each 8 mm in length in one embodiment. 2 It can have a height, width and length of 9mm and 40mm. Packaged switch 247d utilizes switch module 376 of Figure 3p-7. Bridge 368 is not shown in Figure 5f-1 or 5f-2.

[0310] The air-cooled inverter system 514sf allows for dual-sided cooling of the switch 304 of the packaged switch 247d. The case of the packaged switch 247d may be thermally connected to the V+ busbar 576Tsf and the phase busbar 572T, or can be thermally connected to the phase busbar 572T and the V- busbar 578Tsf.

[0311] The phase busbars 572Ta and 572Tb are electrically connected to a load, which may be formed as a primary winding of an isolation transformer. The phase busbars 572Ta and 572Tb are electrically isolated from each other. The die substrate terminals 230 of the packaged switches 247dH of each phase are connected to the corresponding flat surfaces of the V+ busbar 576Tsf by press-fitting, soldering, sintering, or other means to establish thermal and electrical connectivity therebetween. The die clip terminals 344 of the packaged switches 247dHa and 247dHb are connected to the corresponding flat surfaces of the phase busbars 572Ta and 572b, respectively, by press-fitting, soldering, sintering, or other means to establish thermal and electrical connectivity therebetween. The die substrate terminals 230La and 230Lb of the packaged switch 247dL are connected to the corresponding flat surfaces of the phase busbars 572Ta and 572b by press-fitting, soldering, sintering, or other means, respectively, to establish thermal and electrical connectivity therebetween. The die clip terminals 344 of the packaged switch 247dL are electrically connected to the V-busbar 578sf. Each of the busbars 576Tsf, 578Tsf, and 572T includes a channel that holds a respective heat pipe 522. One or more DC link capacitors C may be electrically connected in parallel between the V+busbar 576Tsf and the V-busbar 578Tsf. In one embodiment, the DC link capacitors C may also be thermally connected to the V+busbar 576Tsf and / or the V-busbar 578Tsf. Another capacitor (not shown) may be electrically connected between the phase busbars 572T. Furthermore, this separate capacitor may be thermally connected to one or both of the phase bus bars 572 .

[0312] FIG. 5f-7 includes current symbols representing the current flow through inverter system 514sf at a given moment. More specifically, FIG. 5f-7 illustrates the current flow through inverter system 514sf when a-phase switch 247dH is activated to conduct current from V+ busbar 576Tsf and b-phase switch 247dL is activated to conduct current to V- via V- busbar 578T. All other switches are deactivated.

[0313] Returning to FIG. 5f-6, the inverter 514i includes a control PCB 577sf with opposing sides and a power PCB 575sf with opposing sides. Components can be implemented on the traces on each side of the PCBs 575sf and 577sf. FIG. 5f-6 shows the MCU and the PMIC for each packaged switch 247d of the b-phase, all implemented on the side of the control PCB 577sf facing away from the packaged switch 247d. Additional components can be implemented on the traces on this side of the PCB 577sf and on the side facing the packaged switch 247d. Vias can connect the traces on the other side of the control PCB 577sf. FIG. 5f-6 also shows the gate driver 306 and V_Sense circuit for each packaged switch 247d of the b-phase attached to the traces on the other side of the power PCB 575sf. Additional components such as connectors, diodes, resistors, etc. can be attached to the traces on either side of the Power PCB 575sf. Vias can connect the traces on the other side of the Power PCB 575sf.

[0314] The control PCB 577sf is electrically connected to the power PCB 575sf via the respective sets 464 of connector-leads. In FIG. 5f-6, only the connector leads 602 of the respective sets 464 of the b-phase that connect the control PCB 577sf to the power PCB 575sf are shown. The control PCB 577sf transmits signals (e.g., PWM signals, reset) to and receives signals (e.g., fault, Vv, etc.) from the power PCB 575sff through respective conductive paths including the PCB traces and connector leads of the set 464. The control PCB 577sf also provides a power supply bias voltage to the power PCB 575sf via respective conductive paths including the PCB traces and connector leads in the set 464.

[0315] Although not shown, the ends of each set of connector-leads 464 may be received in respective connectors attached to traces on each side of the opposing PCBs 575sf and 577sf. Additional connectors, not shown, may be attached to traces on the side of the power PCB 575sf that faces the packaged switch 247d. These additional connectors receive the ends of the respective sets of connector-leads 288. Only each set of connector-leads 288g for phase b is shown in FIG. 5f-6.

[0316] (Air-cooled Vienna Rectifier 516VR1) FIG. 5g-1 is a semi-schematic bottom view of an exemplary air-cooled rectifier 516vr1. FIG. 5g-2 is a semi-schematic side view of an exemplary air-cooled rectifier system 516vr1. The air-cooled rectifier system 516vr1 is an example of a three-phase "Vienna" style rectifier. The air-cooled rectifier system 516vr1 cannot operate bidirectionally.

[0317] There are similarities between the air-cooled rectifier 516vr1 and the air-cooled rectifier 502r. However, there are also some differences. For example, the air-cooled rectifier system 516vr1 utilizes a packaged half-bridge 251 as shown in FIG. 4b-1, which may include the switch modules of FIG. 3i-1 and FIG. 3j-1. There may be other differences between the air-cooled rectifiers 516vr1 and 502r. In an alternative embodiment, the packaged half-bridge 255 of FIG. 4d-1 may be utilized.

[0318] With continued reference to FIG. 5g-2, the air-cooled rectifier system 516vr1 has three phases designated ac. Phases a-c each include a packaged half-bridge 251a-251c. The die substrate terminals 230H are electrically and thermally connected to phase bus bars 524a-524c, respectively, which have terminals ta-tc electrically connected to AC power sources φa-φc, respectively. The phase bus bars 524a-524c transfer AC current between the AC power sources φa-φc, respectively, and the packaged half-bridges 251a-251c, and also function as heat sinks. Each of the phase bus bars 524 has a diameter of 8 mm, in one embodiment, respectively. 2 9 mm, and 30 mm in height, width, and length. The cases of the packaged half bridges 251a-251c, in some embodiments, can be thermally connected to the phase bus bars 524a-524c, respectively.

[0319] The air-cooled rectifier system 516vr1 has a bus bar 526vr1 that also functions as a heat sink. The ends of the heat pipes 522 are embedded in and thermally connected to the bus bar 526vr1 and the phase bus bars 524. The die substrate terminals 230L are sintered, soldered, press-fit, or otherwise connected to the bus bar 526vr1. The die substrate terminals 230 are connected to each of the phase bus bars 524 by sintering, soldering, press-fit, or other means.

[0320] Bus bar 526vr1 is electrically connected to the terminals of capacitors C- and C+ as shown. Capacitors C- and C+ may also be thermally connected to bus bar 526vr1. In one embodiment, the terminals of capacitors C- and C+ are connected to bus bar 526vr1 by sintering, soldering, press fitting, or other means. Opposite terminals of capacitors C- and C+ are electrically connected to V- and V+ bus bars 540 and 542, respectively. Bus bars 540 and 542 are symbolically shown in FIG. 5g-1. Bus bars 540 and 542 may have a rectangular cross section. FIG. 5g-2 is a top perspective view of exemplary bus bars 540 and 542. In another embodiment, heat pipes may be embedded in bus bars 540 and 542. If bus bars 540 and 542 are coplanar, bus bars 540 and 542 may have to share a portion of the heat pipe. Assuming that the outer surface of the shared heat pipe is coated with a dielectric, the shared heat pipe does not electrically connect bus bars 540 and 542.

[0321] Diodes D have opposing planar faces that include a cathode and an anode. Referring to FIG. 5g-1, diodes D may be electrically and thermally connected to respective phase bus bars 524. Diode D1 may be electrically and thermally connected to a V- bus bar 540 and diode D2 may be electrically and thermally connected to a V+ bus bar 542. Diodes D are hidden from view in FIG. 5g-2.

[0322] The connections can be direct. For example, the cathodes and anodes of diodes D1a and D2a, respectively, may be connected to busbar 524a by sintering, soldering, or other means, the cathodes and anodes of diodes D1b and D2b, respectively, may be connected to phase busbar 524b by sintering, soldering, or other means, the cathodes and anodes of diodes D1c and D2c, respectively, may be connected to phase busbar 524c by sintering, soldering, or other means, and the anodes and cathodes of diodes D1 and D2 may be connected to V- and V+ busbars 540 and 542, respectively, by sintering, soldering, or other means. Or the connections can be indirect. For example, each of the diodes D can be connected (e.g., sintered) to and between a pair of metal conductors, such as die substrates, each having opposing flat surfaces. The sandwiched combination of the diodes and connected metal conductors can in turn be connected to adjacent busbars (e.g., V busbar 540 and phase busbar 524c) and between them by direct sintering, soldering, or another means, which increases the gap between adjacent busbars to which the diodes are connected.

[0323] The bus bars 526vr1, in one embodiment, are each 8 mm 2 9mm and 100mm in height, width and length. The case of the packaged half bridge 251 can be thermally connected to the bus bar 526vr1. Figure 5g-2 shows the positioning of each phase half bridge 251, phase bar 524 and V+ bus bar 526vr1 relative to each other.

[0324] A metal strap 242, symbolically shown, may be external to the packaged half-bridge 251 and electrically connects the high-side die clip terminal 232H to the low-side die clip terminal 232L.

[0325] There may be further differences between the air-cooled rectifier 516vr1 and the air-cooled rectifier 502r. Referring to FIG. 5g-2, the control PCB 539 of the rectifier system 516vr1 may be implemented with a microcontroller that may be different from the microcontroller implemented in the control PCB 532 of the rectifier system 502r, or the CPU-executable instructions stored in the memory of the microcontroller of the rectifier system 516vr1 may be different from the CPU-executable instructions stored in the memory of the microcontroller implemented in the control PCB 532 of the rectifier system 502r. The control PCBs of the rectifiers 516vr1 and 502r may include a phase-locked loop (PLL) and other components for synchronizing the control of the switch 304 to the frequency (e.g., 60 Hertz) of the three-phase AC input voltage provided by the AC sources φa-φc.

[0326] (Air-cooled Vienna Rectifier 516VR2) FIG. 5g-3 is a semi-schematic bottom view of the air-cooled Vienna rectifier system 516vr2. FIG. 5g-4 is a semi-schematic side view of the air-cooled Vienna rectifier system 516vr1. The air-cooled rectifier systems 516vr1 and 515vr2 are substantially similar. However, there are some differences. For example, the air-cooled rectifier system 516vr2 utilizes an extended busbar 526vr2 and heat sinks 541- and 541+. The V- and V+ busbars 540 and 542 are electrically connected to the heat sinks 541- and 541+, respectively. The capacitors C- and C+ can be electrically and thermally connected to the busbar 526vr2 and the respective heat sinks 541- and 541+. The extended busbar 526vr2 and heat sinks 541- and 541+ can accommodate longer length capacitors C- and C+ (eg, thin wall capacitors housed in a cylindrical package).

[0327] The bus bars 526vr2, in one embodiment, are each 8 mm 29 mm and 180 mm, respectively. Heat sinks 541- and 541+, in one embodiment, can have heights, widths, and lengths of 8 mm 2 It can have a height, width and length of 9mm and 40mm.

[0328] (Air-cooled inverter for switched reluctance motors 518i) The inverters described above can be used to drive motors such as asynchronous induction motors. Figures 5h-1 and 5h-2 show an inverter 518i that can be used to drive a switched reluctance motor. Unlike the three-phase inverters described above, the inverter 518i includes an additional packaged half-bridge 250d electrically connected to a common node NC to which the windings Wa-Wc are also connected, as shown in Figure 5h-1.

[0329] The inverter 518i is similar to the inverter 502i shown in Figure 5a-1. Figure 5h-1 is a semi-schematic end view of an exemplary air-cooled inverter device 518i. Figure 5h-2 is a semi-schematic bottom view of the air-cooled inverter system 518i.

[0330] The air-cooled inverter system 518i utilizes a packaged half-bridge 250 as shown in FIG. 4a-1 or FIG. 4g-1. With continued reference to FIG. 5h-1, the air-cooled inverter system 518i has four phases designated ad. Each of the phases a-d includes a packaged half-bridge 250a-d having die substrate terminals 230L electrically and thermally connected to phase bus bars 524a-d, respectively, which in turn have terminals electrically connected to the stator windings Wa-Wc and a common node NC, respectively. The phase bus bars 524a-d also function as heat sinks. Each of the phase bus bars 524 has a diameter of 8 mm, in one embodiment. 2 The cases of the packaged half bridges 250a-250d may be thermally connected to the phase bus bars 524a-524d, respectively.

[0331] The air-cooled inverter system has a V+ bus bar 543 that also functions as a heat sink. The die substrate terminal 230H is electrically and thermally connected to a V+ bus bar 543 that has a V+ input terminal, which is electrically connected to a battery or other DC voltage source. The V+ bus bars 543 are, in one embodiment, 8 mm wide each. 2 9 mm and 180 mm in height, width, and length. The case of the packaged half bridge 250 may be thermally connected to a V+ bus bar 543.

[0332] 5h-1 shows the relative positioning of each phase's half bridge 250, phase bars 524, and V+ bus bar 543. Metal straps 242 are external to the packaged half bridge 250 and electrically connect the high side die clip terminals 232H to side terminals (not shown) of the low side die substrate 312L.

[0333] The lower die clip terminals 232La-232Ld are electrically connected to a V-busbar having a V-input terminal, which is electrically connected to a battery or other DC voltage source. FIG. 5h-2 shows an exemplary V-busbar 528e having a rectangular cross section. One or more DC link capacitors (not shown) are electrically connected in parallel between the V+ busbar 543 and the V-busbar 528e. One or more of the DC link capacitors may also be thermally connected to the V+ busbar 543.

[0334] Die substrate terminals 230La-230Ld are connected to corresponding flat surfaces of phase bus bars 524a-524d by press-fitting, soldering, sintering, or other means to establish thermal and electrical connectivity therebetween. Each of die substrate terminals 230H is connected to corresponding flat surfaces of V+ bus bar 543 by press-fitting, soldering, sintering, or other means to establish thermal and electrical connectivity therebetween.

[0335] A mechanical structure (not shown in FIG. 5h-1 or FIG. 5h-2) can press-fit die substrate terminals 230La-230Ld against the flat surfaces of phase busbars 524a-524d, respectively, and die substrate terminal 230H against the flat surface of V+ busbar 446. The press-fit should reduce or eliminate problems associated with CTE mismatch. Ideally, the surfaces of the pressed-fit components should be smooth to optimize electrical and / or thermal connections.

[0336] Returning to FIG. 5h-2, inverter 518i also includes a control PCB 545 having opposing sides. Control PCB 545 is electrically connected to packaged half-bridge 250 via respective sets of connector-leads 314. Although not shown, an end of each set of connector-leads 314 may be received in a respective connector that may be mounted on one side of control PCB 545 and electrically connected to traces thereon. Additional components may be connected to traces on that side. A microcontroller or other processor-based control unit, PMIC, or other device is connected to traces on the side of PCB 545 facing away from packaged half-bridge 250. The microcontroller and PMIC are electrically connected to packaged half-bridge 250 via electrical paths consisting of traces and metal vias, connectors, and sets of connector-leads formed on control PCB 545. The PMIC provides bias voltages to the respective switch modules of packaged half-bridge 250. The microcontroller provides PWM and other signals to and receives signals from the packaged half-bridge 250 .

[0337] (Air-cooled inverter 531i) 5i-1-5i-3 are semi-schematic diagrams showing end, bottom and side views of yet another air-cooled inverter system 531i using the packaged half-bridge 251 shown in FIG. 4b-1, which in turn may include the switch modules of FIGS. 3i-1 and 3j-1. More specifically, phases a-c include packaged half-bridges 251a-c and phase busbars PBa-PBc, respectively. Air-cooled inverter system 531i also includes a V+ busbar 533 and a V- busbar 535, both of which also function as heat sinks with channels to hold heat pipes 522. FIG. 5i-2 shows the vertical positioning of half-bridges 251, V+ busbar 533 and V- busbar 535 in each phase relative to one another. In an alternative embodiment of the air-cooled inverter 531i, the packaged half-bridge 251 can be replaced by the packaged half-bridge 261 shown in Figures 4f-1 and 4f-2. In yet another embodiment, the packaged half-bridge 251 can be replaced by the packaged half-bridge 255 of Figure 4d-1.

[0338] The dimensions of the V+ busbar 533 and the V- busbar 535 are substantially similar. In one embodiment, the V+ busbar 533 is 8 mm 2 9 mm, 120 mm in height, width and length. The case of the packaged half bridge 251 may be thermally connected to a V+ busbar 533 and a V− busbar 535.

[0339] Low side die substrate terminals 230L and high side die substrate terminals 230H are connected by press-fit, soldering, sintering, or other means to corresponding flat surfaces of V- busbar 534 and V+ busbar 533, respectively, to establish thermal and electrical connectivity therebetween. In embodiments where the terminals and busbars are pressed together, grease or a similar material can be applied to ensure better thermal and / or electrical connectivity.

[0340] One or more DC link capacitors C may be electrically connected in parallel between the V+ busbar 533 and the V- busbar 535. In the illustrated embodiment, one or more DC link capacitors C1dc are electrically connected between the V+ busbar 533 and the V- busbar 535 and are disposed between the packaged half-bridges 251c and 251b, and one or more DC link capacitors C2dc are electrically connected between the V+ busbar 533 and the V- busbar 535 and are disposed between the packaged half-bridges 251b and 251a. In this configuration, the DC link capacitors C1dc and C2dc may be thermally connected to both the V+ busbar 533 and the V- busbar 535, or the DC link capacitors C1dc and C2dc may be thermally connected to only one of the V+ busbar 533 and the V- busbar 535. For example, DC link capacitor C1dc may be electrically connected to both V+ busbar 533 and V- busbar 535 but thermally connected only to V+ busbar 533, and DC link capacitor C2dc may be electrically connected to both V+ busbar 533 and V- busbar 535 but thermally connected only to V- busbar 535. The thermal connection may cool capacitors C1dc and C2dc. In yet another embodiment, capacitors C1dc and C2dc are electrically and / or thermally connected at their ends between V+ busbar 533 and V- bus 212. In this latter embodiment, capacitors C1dc and C2dc may be located adjacent to the ends of V+ busbar 533 and V- bus 212, rather than between packaged half-bridges 251c and 251b and packaged half-bridges 251b and 251a.

[0341] The phase busbars PBa-PBc are electrically connected to die clip terminals 232 of phases a-c, respectively, as shown. The phase busbars PBa-PBc are symbolically shown in FIG. 5i-2. FIG. 5i-1 shows an exemplary phase busbar PBc formed from metal. The exemplary phase busbar PBc has a rectangular shape and extends from a first end and a second end. The first end is electrically connected to the die clip terminal 232, and the second end is electrically connected to a terminal of the winding Wc. The phase busbar PB has a rectangular cross-sectional shape, as shown in FIG. 5i-3.

[0342] 5i-1 to 5i-3 include current symbols that represent the current flow through the inverter system 531i at a given moment. For example, FIG. 5i-2 shows the current flow through the inverter system 531i when the high-side switch 304H for phase a is activated and conducting current, and the low-side switches 304L for phases b and c are activated and conducting current. All other switches are deactivated in the figures. Importantly, the activated switches are thermally connected to the V+ busbar 533 or the V- busbar 535.

[0343] Returning to FIG. 5i-1, inverter 531i includes a control PCB 537 having opposing sides. Control PCB 537 is electrically connected to packaged half-bridge 251 via respective sets of lead connectors 314. Although not shown, an end of each set of connector-leads 314 can be received in a respective connector that can be attached to a side of control PCB 537 and electrically connected to traces thereon. Additional components can also be connected to traces on the side of PCB 537 that faces the packaged half-bridge. A microcontroller or other processor-based control unit, PMIC, or other device is connected to traces on the side of PCB 537 that does not face packaged half-bridge 251. The microcontroller and PMIC can be electrically connected to packaged half-bridge 251 via electrical paths consisting of traces and vias, connectors, and sets of connector-leads formed on control PCB 537. The PMIC provides bias voltages to the respective switch modules of packaged half-bridge 251. The microcontroller provides PWM and other signals to and receives signals from the packaged half-bridge 251 .

[0344] (Air-cooled rectifier 531r) FIG. 5i-4 is a semi-schematic bottom view of an exemplary air-cooled rectifier 531r. FIG. 5i-5 is a semi-schematic end view of the air-cooled rectifier 531r. The phase busbars PBa-PBc are electrically connected to the AC power sources φa-φc. The rectifier system 531r and the inverter system 531i are substantially similar. The microcontroller implemented on the control PCB of the rectifier system 531r may be different from the microcontroller implemented on the control PCB of the inverter system 531i, or the CPU-executable instructions stored in the memory of the microcontroller implemented on the control PCB of the rectifier system 531r may be different from the CPU-executable instructions stored in the memory of the microcontroller implemented on the control PCB of the inverter system 531i. The control PCB of rectifier 531r may also include a phase-locked loop (PLL) and other components for synchronizing the control of switch 304 to the frequency (e.g., 60 Hertz) of the three-phase AC input voltage provided by AC source φa-φc.

[0345] (Other Air-Cooled Power Converters) The power converters of the present disclosure can be integrated through a common busbar. For example, an AC / AC converter can be created by integrating an air-cooled inverter and a rectifier through a common busbar. An AC / AC converter (e.g., a variable frequency drive controller) converts one form of AC power to another form of AC power. Some AC / AC converters include a DC link electrically connected to the rectifier and inverter to convert input AC power of one frequency to output AC power of another frequency. An air-cooled rectifier and an air-cooled inverter can be integrated through a common busbar to create an air-cooled variable frequency drive controller (VFDC). Figures 5j-1 to 5j-5 are end, bottom, and side views of an exemplary VFDC 508vfd with shared busbar. The VFDC 508vfd integrates the inverter 508i and rectifier 508r of Figures 5d-1 and 5d-5, respectively, through a shared V+ busbar 576vfd and V- busbar 578vfd. The inverter and rectifier section switches 304 are electrically and thermally connected to shared V+ and V- busbars 576vfd and 578vfd as shown. VFDC 508vfd is shown connected to windings Wa-Wb of an electric motor of a machine such as an industrial pump or compressor.

[0346] Other air-cooled power converters can be integrated in a similar manner via common busbars. For example, inverter 504i and rectifier 504r can be combined to create an air-cooled VFDC with common extended V- busbars 528-1 and 528-2 and extended V+ busbar 560, or inverter 514i and rectifier 514r can be combined to create an air-cooled VFCD with common extended V- busbars 578T and extended V+ busbars 576T. FIG. 5k illustrates the integration of inverter 508i of FIG. 5d-2 and passive rectifier of FIG. 5f-5 to create VFDC 508pt. FIG. 5l illustrates the integration of inverter 514i of FIG. 5f-2 and rectifier 514r of FIG. 5f-4 via common busbars 576vfd and 578vfd to create power converter 508Tvfd-1. FIG. 5m illustrates the integration of the inverter 514i of FIG. 5f-2 and the passive rectifier of FIG. 5f-5 via common busbars 576vfd and 578vfd to create a power converter 508Tvfd-2. FIG. 5n illustrates the integration of the rectifier 514r of FIG. 5f-4 and the inverter 514sf of FIG. 5f-7 via common DC busbars 578wh and 576wh to create a power converter 508wh-1, e.g., electrically connected to a winding W of an isolation transformer. FIG. 5o illustrates the integration of the passive rectifier of FIG. 5f-5 and the inverter 514sf of FIG. 5f-7 via common DC busbars 578wh and 576wh to create a power converter 508wh-2, e.g., electrically connected to a winding W of an isolation transformer.

[0347] The air-cooled inverter 510i and the air-cooled rectifier 510r can be connected by a transformer to create an isolated air-cooled DC / DC converter. For example, the output terminals of the inverter 510i can be electrically connected to the respective terminals of the primary side of a transformer (not shown), and the respective terminals of the secondary side of the transformer can be electrically connected to the phase bars 524a and 524b of the rectifier 510r. The isolated DC / DC converter can be connected to other devices such as a three-phase rectifier. For example, the V- and V+ input terminals of the inverter 510i of the isolated DC / DC converter can be electrically connected to the V- and V+ output terminals of the Vienna rectifier 516vr1, and the combination can be utilized for a DC fast charger. A single fan can be used to cool the three-phase rectifier and the inverter portion of the DC / DC converter.

[0348] Although the present disclosure has been described in connection with several embodiments, it is not intended that the present disclosure be limited to the embodiments set forth herein. [Explanation of symbols]

[0349] 247d Packaged Switch 304 Switch 368 Bridge 376 Switch Module 514i Air-cooled Inverter System 522 Heat Pipe 572T phase busbar 576T V+ Busbar 578T V-busbar

Claims

1. 1. A power converter comprising: a first busbar including a channel; a first transistor having first and second terminals between which a current is transmitted when the first transistor is activated, and a first gate terminal for controlling the first transistor, the first terminal being thermally and electrically connected to the first bus bar; a first heat pipe partially received within the channel and thermally connected to the first bus bar; a dielectric that electrically insulates the first heat pipe from the first bus bar; 1. A power converter comprising:

2. a second bus bar; and a second heat pipe thermally connected to the second bus bar; Further provided with the second terminal is electrically connected to the second bus bar; 10. The power converter of claim 1.

3. a second bus bar; and a second heat pipe thermally connected to the second bus bar; a second transistor having first and second terminals between which a current is transmitted when the second transistor is activated, and a second gate terminal for controlling the second transistor, the first terminal of the second transistor being thermally and electrically connected to the second bus bar; Further provided with the first and second transistors are arranged on first and second planes, respectively, the first and second planes being parallel to each other and being arranged between the first and second bus bars; 10. The power converter of claim 1.

4. further comprising a first heat sink thermally connected to the first heat pipe; 10. The power converter of claim 1.

5. The power converter of claim 4 , wherein the first heat sink includes a plurality of heat fins thermally connected to the first heat pipe.

6. The power converter of claim 4 , wherein the first heat sink includes a plurality of heat fins thermally and electrically connected to the first heat pipe.

7. 3. The power converter of claim 2 further comprising a first heat sink thermally connected to said first and second heat pipes.

8. The power converter of claim 3 further comprising a first heat sink thermally connected to said first and second heat pipes.

9. a second bus bar electrically connected to the second terminal; the second bus bar is not thermally connected to a heat pipe; 10. The power converter of claim 1.

10. The power converter of claim 1 , wherein the first bus bar is configured to be electrically connected to a first terminal of a direct current (DC) power source.

11. 2. The power converter of claim 1, wherein the first transistor is configured to conduct greater than or equal to 1 ampere of current between the first and second terminals when activated.

12. a first metal conductor including opposing first and second surfaces; the first terminal is sintered to the first surface; the second surface is electrically and thermally connected to the first bus bar; 10. The power converter of claim 1.

13. a second metal conductor including opposing first and second surfaces; the second terminal is sintered to the first surface of the second metal conductor; the second surface of the second metal conductor is electrically and thermally connected to the second bus bar; 3. The power converter of claim 2.

14. The power converter of claim 1 , wherein the first bus bar is configured to electrically connect to a first terminal of an alternating current (AC) power source.

15. a second transistor having first and second terminals between which a current is transmitted when the second transistor is activated, and a second gate terminal for controlling the second transistor, the first terminal of the second transistor being thermally and electrically connected to the first bus bar; 10. The power converter of claim 1.

16. a third transistor having first and second terminals between which a current is transmitted when the third transistor is activated, and a third gate terminal for controlling the third transistor, the first terminal of the third transistor being thermally and electrically connected to the first bus bar; 16. The power converter of claim 15.

17. 17. The power converter of claim 16, wherein a second terminal of the first transistor, a second terminal of the second transistor, and a second terminal of the third transistor are electrically connected to first, second, and third stator windings (Wa, Wb, Wc) of an electric motor, respectively.

18. 17. The power converter of claim 16, wherein a second terminal of the first transistor, a second terminal of the second transistor, and a second terminal of the third transistor are electrically connected to first, second, and third stator windings, respectively, of a three-phase alternating current (AC) current source.

19. 10. The power converter of claim 1 further comprising a gate driver circuit configured to control a voltage at the first gate terminal.

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