Current source inverter with hybrid switches

Abstract

A current source inverter includes a first phase leg comprising a plurality of switching devices, a second phase leg comprising a plurality of switching devices, and a third phase leg comprising a plurality of switching devices. The current source inverter further includes a zero state phase leg comprising at least one switching device, wherein the zero state phase leg is configured to transition from an open state to prevent current flow to a closed state to allow current flow between a positive terminal and a negative terminal during a dead time.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to current source inverters, and more particularly, to a current source inverter and rectifier with a hybrid switching implementation. BACKGROUND

[0002] Hybrid electric or battery electric vehicle transmissions typically include one or more high voltage electric motor machines, such as electric traction motors. The electric motor machines deliver power to, charge, or draw power from a rechargeable direct current (DC) battery pack. Energized electric motor machines adjust the torque of various gear sets of the transmission to achieve optimal system efficiency. Converters are typically used to convert voltages to suitable levels for use by the electric motor machines and / or accessory loads in the vehicle.

[0003] Semiconductor switches of an inverter, such as a current source inverter or a voltage source inverter, are controlled via pulse width modulation or other switching control signals to convert a battery output voltage to an alternating current (AC) output voltage. The AC output voltage from the inverter is ultimately transmitted to individual phase windings of an electric motor machine, and the energized electric motor machine powers a drivetrain of a vehicle. SUMMARY

[0004] According to several aspects, a current source inverter includes a first phase leg including a plurality of switching devices, a second phase leg including a plurality of switching devices, and a third phase leg including a plurality of switching devices. The current source inverter also includes a zero state phase leg including at least one switching device, wherein the zero state phase leg is configured to transition from an open state to prevent current flow to a closed state to allow current flow between a positive terminal and a negative terminal during a dead time.

[0005] In other features, the plurality of switching devices of the first phase leg includes bidirectional switching devices and unidirectional switching devices, wherein a node connection to a load is disposed between the bidirectional switching devices and the unidirectional switching devices.

[0006] In other features, the bidirectional switching devices include a first switch and a second switch connected in series.

[0007] In other features, the first switch and the second switch include voltage controlled switches.

[0008] In other features, the voltage controlled switches include at least one of a silicon insulated gate bipolar transistor (IGBT), a silicon carbide metal oxide semiconductor field effect transistor (MOSFET), a silicon super junction MOSFET, a gallium nitride (GaN) field effect transistor (FET), a SiC junction gate field effect transistor (JFET), a wide bandgap (WBG) device, or an ultra-wide bandgap device (UWBG).

[0009] In other features, the unidirectional switching device includes a switch in series with a diode.

[0010] In other features, the plurality of switching devices of the first bridge leg includes at least a first unidirectional switching device and a second unidirectional switching device connected in series, the plurality of switching devices of the second bridge leg includes at least a first unidirectional switching device and a second unidirectional switching device connected in series, and the plurality of switching devices of the third bridge leg includes at least a first bidirectional switching device and a second directional switching device connected in series.

[0011] In other features, at least one switching device of the zero-state phase bridge leg includes a unidirectional switching device.

[0012] In other features, at least one switching device of the zero-state phase bridge leg includes a bidirectional switching device.

[0013] According to several aspects, a current source inverter includes a first phase bridge leg including a plurality of switching devices, a second phase bridge leg including a plurality of switching devices, and a third phase bridge leg including a plurality of switching devices. The current source inverter further includes a zero-state phase bridge leg including at least one bidirectional switching device, wherein the zero-state phase bridge leg is configured to transition from an open state to prevent current flow to a closed state to allow current flow between a positive terminal and a negative terminal during a dead-time.

[0014] In other features, the plurality of switching devices of the first phase bridge leg includes a bidirectional switching device and a unidirectional switching device, wherein a node connection to a load is disposed between the bidirectional switching device and the unidirectional switching device.

[0015] In other features, the bidirectional switching device includes a first switch and a second switch connected in series.

[0016] In other features, the first switch and the second switch include voltage-controlled switches.

[0017] According to several aspects, a current source inverter includes a first phase bridge leg including a plurality of switching devices, a second phase bridge leg including a plurality of switching devices, and a third phase bridge leg including a plurality of switching devices. The current source inverter further includes a zero-state phase bridge leg including at least one unidirectional switching device, wherein the zero-state phase bridge leg is configured to transition from an open state to prevent current flow to a closed state to allow current flow between a positive terminal and a negative terminal during a dead-time.

[0018] In other features, the plurality of switching devices of the first phase bridge leg includes a bidirectional switching device and a unidirectional switching device, wherein a node connection to a load is disposed between the bidirectional switching device and the unidirectional switching device.

[0019] In other features, the bidirectional switch device includes a first switch and a second switch connected in series.

[0020] In other features, the first switch and the second switch include voltage controlled switches.

[0021] In other features, the voltage controlled switches include at least one of a silicon insulated gate bipolar transistor (IGBT), a silicon carbide metal oxide semiconductor field effect transistor (MOSFET), a silicon super junction MOSFET, a gallium nitride (GaN) field effect transistor (FET), a SiC junction gate field effect transistor (JFET), a wide bandgap (WBG) device, or an ultra-wide bandgap device (UWBG).

[0022] In other features, the unidirectional switch device includes a switch connected in series with a diode.

[0023] In other features, the plurality of switch devices of the first bridge arm includes at least a first unidirectional switch and a second unidirectional switch connected in series, the plurality of switch devices of the second bridge arm includes at least a first unidirectional switch and a second unidirectional switch connected in series, and the plurality of switch devices of the third bridge arm includes at least a first bidirectional switch and a second directional switch connected in series.

[0024] Other applicable ranges will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings described herein are for purposes of illustration only and are not intended to limit the scope of the present disclosure in any way.

[0026] Figure 1 is a block diagram of an electrical system in accordance with example embodiments;

[0027] Figures 2 to 4 is a circuit diagram of a current source inverter in accordance with various embodiments;

[0028] Figure 5 is a circuit diagram of a zero state bridge arm of a current source inverter in accordance with example embodiments; and

[0029] Figure 6 is a plot showing example gate control signals including a dead time between two switching states. DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0031] Figure 1An example electrical system 100 according to example embodiments is shown. The electrical system 100 can include vehicle components, such as a vehicle’s powertrain and / or traction drive components, whose general function can include powering a traction motor to generate motor torque and delivering the motor torque to drive wheels for propulsion of the vehicle or for performing other useful work on the vehicle. As shown, the electrical system 100 can include a battery 102, a controller 104, a gate driver 106, a current source inverter 108, and a motor 110.

[0032] In example embodiments, the battery 102 can include an on-board rechargeable energy storage system (RESS) that can include one or more high-voltage standalone rechargeable battery packs adapted to store high-voltage electrical energy used to propel an electrically driven vehicle. For example, depending on the desired vehicle range, total vehicle weight, and rated power of various loads drawing power from the RESS, the RESS can be a deep cycle, high amp capacity battery system rated at approximately 400 to approximately 800 volts direct current (VDC) or higher.

[0033] The controller 104 can include at least one processor and sufficient memory for storing computer readable instructions. The memory includes tangible non-transitory memory, such as read-only memory, whether optical, magnetic, flash, or otherwise. The controller 104 also includes a sufficient amount of random access memory, electrically erasable programmable read-only memory, and the like, as well as high speed clock, analog-to-digital and digital-to-analog circuitry, and input / output circuitry and devices, and appropriate signal conditioning and buffer circuitry. The controller 104 can receive a charge request signal from one or more electronic control units (ECUs) of the vehicle. For example, an ECU associated with the vehicle can provide a torque increase request signal. Based on the torque increase request signal, the controller 104 can transmit a control signal to the gate driver 106 to control one or more switches within the current source inverter 108 to supply an AC output voltage or output current to the load 110. The current source inverter 108 can dominate the transfer of electrical energy to and from the load 110. As shown, the gate driver 106 can be connected to the current source inverter 108 via a bus 112. The bus 112 provides a connection between the gate driver 106 and each of the switches and / or bridge arms of the current source inverter 108. In various embodiments, the controller 104 can include a pulse width modulator that provides a pulse width modulated signal to the gate driver 106. The gate driver 106 can operate the current source inverter 108 based on the signal received from the pulse width modulator.

[0034] In example embodiments, the load 110 includes a traction motor 202 (see Figure 2 ). The traction motor 202 can include a plurality of machine windings that can provide at least three phase currents to generate a rotating magnetic field to rotate a rotor of the traction motor 202 to propel the vehicle.

[0035] Figures 2 to 4 Example embodiments of the current source inverter 108 are shown. As discussed in more detail below, Figure 2 and Figure 3 the current source inverter 108 shown in includes phase legs that include different switches, e.g., one switch of a phase leg includes a full bi-directional switching device and another switch includes a reverse voltage blocking unidirectional switching device. As discussed below, the unidirectional switching device can include at least two voltage controlled switches connected in series. Figure 4 Example embodiments are shown in which the current source inverter 108 includes two legs each containing at least two unidirectional switching devices and a single leg containing at least two bi-directional switching devices.

[0036] Each of the embodiments can further include another leg (e.g., a zero state leg) that includes at least one voltage controlled switch. As discussed herein, the zero state leg can be controlled to mitigate an open circuit within the current source inverter 108. In example embodiments, the zero state leg can contain a voltage controlled switch (e.g., a unidirectional switching device) in series with a diode. In another example embodiment, the zero state leg can contain a bi-directional switching device that includes two voltage controlled switches connected in series. In these embodiments, the gate terminals of the voltage controlled switches of the bi-directional switching device are connected to the same output of the gate driver 106.

[0037] The voltage controlled switches can include, but are not limited to, silicon insulated gate bipolar transistors (IGBTs), silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs), silicon (Si) super junction MOSFETs, gallium nitride (GaN) field effect transistors (FETs), SiC junction gate field effect transistors (JFETs), other wide bandgap (WBG) or ultra-wide bandgap (UWBG) semiconductor power switching devices, or other suitable switches for which a gate signal is applied to its corresponding gate to change the on / off state of a given switch. It should be understood that in some embodiments, the switches can include current controlled switches.

[0038] As used herein, a diode can refer to diodes of various types (e.g., p-n junction type, Schottky barrier type, etc.) having various ratings. As understood by one skilled in the art, a diode is a two-terminal electrical component that conducts current primarily in one direction from anode to cathode.

[0039] With reference to Figure 2 and Figure 3 The current source inverter 108 includes a zero-state bridge arm 204 and a plurality of phase bridge arms 206, 208, 210 including one or more switching devices as described in greater detail below. The phase bridge arms 206, 208, 210 are each connected to a corresponding machine phase terminal of the traction motor 202, e.g., one of the machine windings of the traction motor 202.

[0040] As shown, the phase bridge arms 206, 208, 210 each include respective fully bidirectional switching devices and / or reverse voltage blocking unidirectional switching devices. The phase bridge arm 206 includes a first bidirectional switching device 218 including a first switch 220 and a second switch 222, e.g., voltage controlled switches. The phase bridge arm 206 also includes a unidirectional switching device 290 including a third switch 224 and a first diode 226. The phase bridge arm 208 includes a second bidirectional switching device 228 including a fourth switch 230 and a fifth switch 232. The phase bridge arm 208 also includes a unidirectional switching device 292 including a sixth switch 234 and a second diode 236. The phase bridge arm 210 includes a third bidirectional switching device 238 including a seventh switch 240 and an eighth switch 242. The phase bridge arm 210 also includes a unidirectional switching device 294 including a ninth switch 244 and a third diode 246.

[0041] The bus 112 can be connected to various gate terminals of the switches 220, 222, 224, 230, 232, 234, 240, 242, 244. In an example embodiment, the gate terminals of the switches including the bidirectional switching devices 218, 228, 238 are connected to corresponding outputs of the gate driver 106 (e.g., the bus 112). For example, the gate terminals of the switches 220, 222 are connected to a first output, the gate terminals for the switches 230, 232 are connected to a second output, and the gate terminals for the switches 240, 242 are connected to a third output. Thus, the gate terminals for the bidirectional switching devices 218, 228, 238 each receive a corresponding gate control signal. The gate terminals for the switches 222, 232, 242 are connected to separate gate driver 106 outputs.

[0042] Based on control signals from the controller 104, the gate driver 106 provides gate control signals to gate terminals of the switches 220, 222, 224, 230, 232, 234, 240, 242, 244 to cause the switches 220, 222, 224, 230, 232, 234, 240, 242, 244 to transition between open and closed states to control current flow within the current source inverter 108.

[0043] As shown in Figure 2 and Figure 3 The nodes 280, 282, 284 connecting the respective phase legs 206, 208, 210 to the traction motor 202 are positioned between the bidirectional switching devices 218, 228, 238 of the phase legs 206, 208, 210 and the switches 224, 234, 244 connected in series with the diodes 226, 236, 246 of the corresponding phase legs 206, 208, 210. In these embodiments, the switches 224, 234, 244 connected in series with the diodes 226, 236, 246 (e.g., unidirectional switching devices 290, 292, 294) allow current flow in one direction. As shown in Figure 2 and Figure 3 In some embodiments, the positions of the bidirectional switching devices 218, 228, 238 and the unidirectional switching devices 290, 292, 294 can be exchanged (e.g., interchangeable), as shown in Figure 2 and Figure 3 While only three (3) phases are shown, it should be understood that various embodiments of the present disclosure can be extended to an N number of phases, where N is an integer.

[0044] Figure 4 An example embodiment of the current source inverter 106 including phase legs 302, 304, 306 is shown. As shown, the phase legs 302, 304 include unidirectional switching devices 306, 308, 310, 312. The unidirectional switching devices 306, 308, 310, 312 each include a respective switch 314, 316, 318, 320 connected in series with a diode 322, 324, 326, 328. As shown, nodes 330, 332 are positioned between the unidirectional switching devices of the phase legs 302, 304. The phase leg 306 includes a first bidirectional switching device 334 and a second bidirectional switching device 336. The bidirectional switching device 334 includes switches 338, 340 connected in series, and the bidirectional switching device 336 includes switches 342, 344 connected in series. A node 346 connecting the phase leg 306 to the traction motor 202 is positioned between the bidirectional switching devices 334, 336.

[0045] The zero-state phase leg 204 can provide a connection between the positive terminal 272 and the negative terminal 274 to mitigate an open circuit within the current source inverter 108. In Figures 2 to 4 In the embodiment shown in FIG. 1, the zero-state phase leg 204 can include a unidirectional switching device 276. The unidirectional switching device 276 includes a switch 290 connected in series with a diode 292. Figure 5 An example embodiment of the zero-state phase leg 204 including a bidirectional switching device 278 is shown. The bidirectional switching device 278 can include switches 294, 296 connected in series.

[0046] The current source inverter 108 can receive current from the current source 201 (e.g., current provided by the battery 102 and the inductor 203). The inductor 203 is connected between the current source 201 and the positive terminal 272. The inductor 203 can be various types of inductors having various inductance values. As understood by one skilled in the art, an inductor is a passive, two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. As understood by one skilled in the art, the inductance value of the inductor 203 can be selected to carry a load current based on the application area of the current source inverter 108.

[0047] In the embodiment shown, the total number of gate signals provided by the gate driver 106 can be seven (7) because the gate terminal for each unidirectional switching device and each bidirectional switching device is connected to an output of the gate driver 106. As such, the current source inverter 108 described herein can require relatively lower gate signal complexity and lower cost as compared to a current source inverter containing all bidirectional switching devices. The efficiency of the current source inverter 108 can also be relatively higher as compared to a current source inverter containing all unidirectional switching devices.

[0048] Figure 6 An example plot 600 of gate control signals generated by the gate driver 106 is shown. A dead band time (DB) 602 is included between a first switching state 604 and a second switching state 606. The switching states 604, 606 refer to time periods in which various switches used to control the phase legs of the current source inverter 108 supply current from the current source 201 to the load 110. As shown, portions of the switching states 604, 606 can at least partially overlap with the dead band time 602. During the dead band time 602, the zero-state phase leg 204 transitions from an open state to a closed state to mitigate a possible open circuit within the phase legs of the current source inverter 108.

[0049] The description of the present disclosure is merely exemplary in nature and variations that do not depart from the spirit and scope of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.

Claims

1. A current source inverter, comprising: The first phase bridge arm includes multiple switching devices; The second phase bridge arm includes multiple switching devices; The third phase bridge arm includes multiple switching devices; as well as The zero-state phase bridge arm includes at least one switching device, wherein the zero-state phase bridge arm is configured to transition from an open state to a closed state to allow current flow between the positive and negative terminals during the dead time. The plurality of switching devices in the first phase bridge arm include bidirectional switching devices and unidirectional switching devices, wherein the node connection to the load is disposed between the bidirectional switching devices and the unidirectional switching devices. The multiple switching devices of the second phase bridge arm include at least a first unidirectional switch and a second unidirectional switch connected in series, and the multiple switching devices of the third phase bridge arm include at least a first bidirectional switch and a second bidirectional switch connected in series.

2. The current source inverter according to claim 1, wherein, The bidirectional switching device includes a first switch and a second switch connected in series.

3. The current source inverter according to claim 2, wherein, The first switch and the second switch include voltage-controlled switches.

4. The current source inverter according to claim 3, wherein, The voltage-controlled switch includes at least one of a silicon insulated gate bipolar transistor (IGBT), a silicon carbide metal oxide semiconductor field-effect transistor (MOSFET), a silicon superjunction MOSFET, a gallium nitride (GaN) field-effect transistor (FET), a SiC junction gate field-effect transistor (JFET), a wide bandgap (WBG) device, or an ultra-wide bandgap (UWBG) device.

5. The current source inverter according to claim 1, wherein, The unidirectional switching device includes a switch connected in series with a diode.

6. The current source inverter according to claim 1, wherein, At least one switching device of the zero-state phase bridge arm includes a unidirectional switching device.

7. The current source inverter according to claim 1, wherein, At least one switching device of the zero-state phase bridge arm includes a bidirectional switching device.

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