Power Module and Its Fabrication Method

Abstract

This application relates to a power module and its fabrication method. The power module includes: a printed circuit board; and an inverter circuit electrically connected to the printed circuit board for converting an externally input DC signal into an AC signal, comprising: a first inverter circuit disposed on one side of the printed circuit board along a first direction; and a second inverter circuit disposed on the other side of the printed circuit board along the first direction. The first and second inverter circuits are connected in parallel and symmetrically arranged to reduce the parasitic inductance of the power module. Through this method, the power module can reduce the parasitic inductance of the traces, thereby avoiding large voltage overshoot and electromagnetic interference during inverter circuit operation.

Description

Technical Field

[0001] This application relates to the field of power semiconductor device technology, specifically to power modules and their fabrication methods. Background Technology

[0002] Due to their advantages in switching speed, voltage withstand capability, and temperature resistance, silicon carbide (SiC) devices are widely used in electric vehicles and photovoltaic inverters. A single-phase bridge power module's switching arm consists of two SiC devices connected in series. The two SiC devices in the switching arm cannot be turned on simultaneously. Because the current-carrying capacity of a single SiC device is relatively small, single-phase bridge power modules are generally composed of multiple switching arms connected in parallel to increase the current-carrying capacity. However, poor placement of multiple SiC devices in the power module can lead to excessive parasitic inductance in the traces, resulting in significant voltage overshoot and electromagnetic interference when the SiC devices are turned on and / or off. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this application provides a power module and its fabrication method, which can solve the problem of excessive parasitic inductance in the power module leading to large voltage overshoot and electromagnetic interference.

[0004] This application provides a power module, the power module comprising: a printed circuit board; an inverter circuit electrically connected to the printed circuit board for converting an externally input DC signal into an AC signal, comprising: a first inverter circuit disposed on one side of the printed circuit board along a first direction; and a second inverter circuit disposed on the other side of the printed circuit board along the first direction; wherein the first inverter circuit and the second inverter circuit are connected in parallel and symmetrically arranged to reduce the parasitic inductance of the power module.

[0005] In one embodiment, the power module further includes a first positive power terminal, a second positive power terminal, a negative power terminal, and an AC output terminal, wherein the first positive power terminal, the second positive power terminal, the negative power terminal, and the AC output terminal are electrically connected to the printed circuit board; the first inverter circuit includes: a first upper switch assembly, one end of which is connected to the first positive power terminal; and a first lower switch assembly, one end of which is connected to the negative power terminal; wherein the first upper switch assembly and the first lower switch assembly are connected in series, and a port is led out from the node between the first upper switch assembly and the first lower switch assembly and connected to the AC output terminal to output the AC signal; the second inverter circuit includes: a second upper switch assembly, one end of which is connected to the second positive power terminal; and a second lower switch assembly, one end of which is connected to the negative power terminal; wherein the second upper switch assembly and the second lower switch assembly are connected in series, and another port is led out from the node between the second upper switch assembly and the second lower switch assembly and connected to the AC output terminal to output the AC signal.

[0006] In one embodiment, the first positive power terminal, the second positive power terminal, and the negative power terminal are disposed on one side of the printed circuit board along the second direction, and the AC output terminal is disposed on the other side of the printed circuit board along the second direction; the first positive power terminal and the second positive power terminal are respectively located on both sides of the negative power terminal; the first upper switch assembly and the second upper switch assembly are symmetrically arranged, and the first lower switch assembly and the second lower switch assembly are symmetrically arranged; the first inverter circuit is closer to the first positive power terminal than the second inverter circuit, the first lower switch assembly is closer to the negative power terminal than the first upper switch assembly, and the second lower switch assembly is closer to the negative power terminal than the second upper switch assembly; wherein, the second direction is perpendicular to the first direction.

[0007] In one embodiment, the power module further includes an upper switch drive lead-out terminal and a lower switch drive lead-out terminal, which are electrically connected to the printed circuit board. The upper switch drive lead-out terminal and the lower switch drive lead-out terminal are located on opposite sides of the AC output terminal, with the upper switch drive lead-out terminal being closer to the second inverter circuit than the lower switch drive lead-out terminal. The printed circuit board includes: an upper switch drive signal bus, comprising a first upper switch drive bus and a second upper switch drive bus, the first upper switch drive bus being located between the first upper switch assembly and one edge of the printed circuit board along the first direction, and the second upper switch drive bus being located between the second upper switch assembly and the other edge of the printed circuit board along the first direction. The first upper switch drive bus is connected to the second upper switch drive bus via a bonding wire, and the second upper switch drive bus is connected to the upper switch drive lead-out terminal; and a lower switch drive signal bus, located between the first lower switch assembly and the second lower switch assembly, which is connected to the lower switch drive lead-out terminal via a bonding wire.

[0008] In one embodiment, the first upper switch assembly, the first lower switch assembly, the second upper switch assembly, and the second lower switch assembly each include a plurality of switch units; the control terminal of each switch unit in the first upper switch assembly is connected to the first upper switch drive busbar via a bonding wire, the control terminal of each switch unit in the second upper switch assembly is connected to the second upper switch drive busbar via a bonding wire, and the control terminal of each switch unit in the first lower switch assembly and the second lower switch assembly is connected to the lower switch drive signal busbar via a bonding wire.

[0009] In one embodiment, the switching unit is a silicon carbide MOS transistor.

[0010] In one embodiment, the power module further includes a first Kelvin source terminal and a second Kelvin source terminal, which are electrically connected to the printed circuit board. The first Kelvin source terminal is located between the upper switch drive terminal and the AC output terminal, and the second Kelvin source terminal is located between the lower switch drive terminal and the AC output terminal. The printed circuit board further includes an upper switch Kelvin source busbar, including a first upper switch Kelvin busbar and a second upper switch Kelvin busbar. The first upper switch Kelvin busbar is located between the first upper switch drive busbar and the first upper switch assembly. The Kelvin busbar is connected to the second upper switch Kelvin busbar via a bonding wire, and the second upper switch Kelvin busbar is connected to the first Kelvin source terminal. The lower switch Kelvin source busbar is located between the lower switch drive signal busbar and the second lower switch assembly, and the lower switch drive signal busbar is connected to the second Kelvin source terminal via a bonding wire. The source of each switch unit in the first upper switch assembly is connected to the first upper switch Kelvin busbar, the source of each switch unit in the second upper switch assembly is connected to the second upper switch Kelvin busbar, and the source of each switch unit in both the first and second lower switch assemblies is connected to the lower switch Kelvin source busbar.

[0011] In one embodiment, the first upper switch assembly, the first lower switch assembly, the second upper switch assembly, and the second lower switch assembly each include five of the aforementioned switch units.

[0012] In one embodiment, the power module further includes a thermistor, a first temperature sensing lead-out terminal, and a second temperature sensing lead-out terminal. The thermistor is disposed on the printed circuit board and located between the first upper switch assembly and the first upper switch Kelvin busbar. The first temperature sensing lead-out terminal and the second temperature sensing lead-out terminal are located between the lower switch drive lead-out terminal and one edge of the printed circuit board along the first direction.

[0013] In one embodiment, the thermistor is a platinum resistance thermometer.

[0014] In one embodiment, the power module further includes a sampling signal output terminal located between the upper switch drive output terminal and the other edge of the printed circuit board along the first direction, and the second positive power terminal is connected to the sampling signal output terminal via a bonding wire.

[0015] In one embodiment, the printed circuit board further includes a substrate layer and a conductive layer. The upper switch drive signal bus, the lower switch drive signal bus, the upper switch Kelvin source bus, and the lower switch Kelvin source bus are located on the side of the substrate layer facing the inverter circuit, and the conductive layer is located on the other side of the substrate layer away from the inverter circuit.

[0016] In one embodiment, the substrate layer is a silicon nitride ceramic layer, and the conductive layer is a copper-clad layer.

[0017] In one embodiment, the power module further includes a heat dissipation device fixed to the printed circuit board.

[0018] In one embodiment, the heat dissipation device is a needle-fin water-cooled radiator.

[0019] In one embodiment, the power module further includes a housing for sealing the inverter circuit and the printed circuit board.

[0020] In one embodiment, both the first inverter circuit and the second inverter circuit include multiple parallel bridge arms, each of the bridge arms including two switching units connected in series. The two switching units are arranged along a second direction and staggered along the first direction to reduce thermal coupling between the two switching units; wherein the second direction is perpendicular to the first direction.

[0021] This application also provides a method for manufacturing a power module, the method comprising the following steps: fabricating a circuit layer on a substrate layer by UV curing and etching processes to obtain a printed circuit board; fixing a switching unit, power terminals, and signal lead-out terminals at preset positions on the printed circuit board according to a preset layout to obtain a first semi-finished product; fixing the first semi-finished product to a heat dissipation device by a soldering process to obtain a second semi-finished product; placing the second semi-finished product in a mold and fabricating a packaging shell by an injection molding process to obtain the power module; wherein the packaging shell seals the printed circuit board and the switching unit.

[0022] In one embodiment, fixing the switching unit, power terminal, and signal lead-out terminal to preset positions on the printed circuit board according to a preset layout to obtain a first semi-finished product includes the following steps: soldering the switching unit to preset positions on the printed circuit board according to a preset layout using a soldering process to complete the first process; based on the first process, fixing the power terminal and the signal lead-out terminal to preset positions according to a preset layout using an ultrasonic bonding process to complete the second process; based on the second process, fixing the control terminal and Kelvin source electrode of the switching unit to preset positions according to a preset layout using an ultrasonic bonding process to obtain the first semi-finished product.

[0023] The beneficial effects of this application's embodiments are as follows: Unlike existing technologies, the power module provided in this application includes: a printed circuit board; and an inverter circuit electrically connected to the printed circuit board for converting externally input DC signals into AC signals, comprising: a first inverter circuit disposed on one side of the printed circuit board along a first direction; and a second inverter circuit disposed on the other side of the printed circuit board along the first direction. The first inverter circuit and the second inverter circuit are connected in parallel and symmetrically arranged to reduce the parasitic inductance of the power module. Through this method, the power module can reduce the parasitic inductance of the traces, thereby avoiding large voltage overshoot and electromagnetic interference during the operation of the inverter circuit. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of an embodiment of the power module provided in this application;

[0026] Figure 2 This is a schematic diagram of another embodiment of the power module provided in this application;

[0027] Figure 3 This is a schematic diagram of another embodiment of the power module provided in this application;

[0028] Figure 4 yes Figure 3 A schematic diagram of an embodiment of an inverter circuit;

[0029] Figure 5 yes Figure 3 A schematic diagram of another embodiment of the inverter circuit;

[0030] Figure 6 yes Figure 2 A schematic diagram of the structure of a printed circuit board according to an embodiment;

[0031] Figure 7 yes Figure 6 A front view of the printed circuit board;

[0032] Figure 8 This is a flowchart illustrating an embodiment of the method for fabricating a power module provided in this application.

[0033] Figure 9 yes Figure 8 A flowchart of an embodiment of step S220. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] The power module provided in this application includes: a printed circuit board; and an inverter circuit electrically connected to the printed circuit board for converting an externally input DC signal into an AC signal, comprising: a first inverter circuit disposed on one side of the printed circuit board along a first direction; and a second inverter circuit disposed on the other side of the printed circuit board along the first direction; wherein the first inverter circuit and the second inverter circuit are connected in parallel and symmetrically arranged to reduce the parasitic inductance of the power module. Through the above method, the power module can reduce the parasitic inductance of the traces, thereby avoiding large voltage overshoot and electromagnetic interference during the operation of the inverter circuit.

[0038] Please refer to the following: Figure 1 , Figure 2 and Figure 3 , Figure 1 This is a schematic diagram of the structure of an embodiment of the power module provided in this application. Figure 2 This is a schematic diagram of another embodiment of the power module provided in this application. Figure 3 This is a schematic diagram of another embodiment of the power module provided in this application. The power module 100 may include, but is not limited to, a printed circuit board 110, an inverter circuit 120, a power terminal set 130, a signal terminal set 140, a heat dissipation device 150, and a package housing 160. The inverter circuit 120 is electrically connected to the printed circuit board 110. The inverter circuit 120 is used to convert the externally input DC signal into an AC signal. The inverter circuit 120 is symmetrically arranged on one side of the printed circuit board 110 to reduce the parasitic inductance of the traces and avoid large voltage overshoot and electromagnetic interference in the commutation circuit. The power terminal set 130 is electrically connected to the printed circuit board 110 to input DC signals to the inverter circuit 120 and output AC signals to the load. The signal terminal set 140 is electrically connected to the printed circuit board 110 to input control signals and output detection signals. The heat dissipation device 150 is fixed to the other side of the printed circuit board 110 to dissipate heat from the inverter circuit 120. The plane containing the heat dissipation device 150 is opposite to the plane containing the inverter circuit 120. The enclosure 160 is used to seal and cover the inverter circuit 120 and the printed circuit board 110 to protect the internal circuit structure of the power module 100, thus enabling it to be used in harsh environments.

[0039] Optionally, the heat dissipation device 150 can be a pin-fin water-cooled radiator. Pin-fin water-cooled radiators have a high heat dissipation coefficient and can promptly conduct the heat generated by the inverter circuit to the outside, preventing excessive temperature from affecting the performance of the power module.

[0040] Furthermore, please refer to the following: Figure 3 and Figure 4 , Figure 4 yes Figure 3 A schematic diagram of an embodiment of the inverter circuit is provided. The inverter circuit 120 may include, but is not limited to, a first inverter circuit 121 and a second inverter circuit 122. The first inverter circuit 121 and the second inverter circuit 122 are connected in parallel. The first inverter circuit 121 is disposed on one side of the printed circuit board 110 along a first direction. The second inverter circuit 122 is disposed on the other side of the printed circuit board 110 along the first direction. The first inverter circuit 121 and the second inverter circuit 122 are symmetrically arranged to reduce the parasitic inductance of the power module 100 and to avoid large voltage overshoot and electromagnetic interference when the switching units in the first inverter circuit 121 and the second inverter circuit 122 are turned on and / or turned off. Wherein, the first direction is... Figure 3 The direction indicated by the X-axis.

[0041] Furthermore, please refer to the following: Figure 2 and Figure 3 The power terminal set 130 may include, but is not limited to, a first positive power terminal 131, a second positive power terminal 132, a negative power terminal 133, and an AC output terminal 134. The first positive power terminal 131, the second positive power terminal 132, the negative power terminal 133, and the AC output terminal 134 are electrically connected to the printed circuit board 110. The first positive power terminal 131, the second positive power terminal 132, and the negative power terminal 133 are located on one side of the printed circuit board 110 along a second direction. The AC output terminal 134 is located on the other side of the printed circuit board 110 along the second direction. The first positive power terminal 131 and the second positive power terminal 132 are located on opposite sides of the negative power terminal 133. The first inverter circuit 121 is closer to the first positive power terminal 131 than the second inverter circuit 122. The second direction is... Figure 3 The direction indicated by the Y-axis.

[0042] Further, please refer to Figure 2 , Figure 3 and Figure 4The first inverter circuit 121 may include, but is not limited to, a first upper switch assembly 1211 and a first lower switch assembly 1212. One end 1211 of the first upper switch assembly is connected to the first positive power terminal 131. One end of the first lower switch assembly 1212 is connected to the negative power terminal 133. The first upper switch assembly 1211 and the first lower switch assembly 1212 are connected in series. A port is led out from the node between the first upper switch assembly 1211 and the first lower switch assembly 1212 and connected to the AC output terminal 134 to output an AC signal.

[0043] Please see Figure 3 and Figure 5 , Figure 5 yes Figure 3 A schematic diagram of another embodiment of the inverter circuit is shown. In this embodiment, both the first upper switching assembly 1211 and the first lower switching assembly 1212 include five switching units T. The switching units T in the first upper switching assembly 1211 and the corresponding switching units T in the first lower switching assembly 1212 are connected in series to form a bridge arm 1201. The first inverter circuit 121 includes five bridge arms 1201 connected in parallel. The two switching units T in each bridge arm 1201 are arranged along a second direction and staggered along a first direction to reduce thermal coupling between the two switching units T. The second direction is perpendicular to the first direction. It can be understood that by staggering the positions of the two series-connected switching units T in the bridge arm, the thermal coupling between the switching units T can be reduced, thereby reducing the junction temperature of the switching units T in the power module 100 and improving the performance of the power module 100.

[0044] Similarly, please see Figure 2 , Figure 3 and Figure 4 The second inverter circuit 122 may include, but is not limited to, a second upper switch assembly 1221 and a second lower switch assembly 1222. One end of the second upper switch assembly 1221 is connected to the second positive power terminal 132. One end of the second lower switch assembly 1222 is connected to the negative power terminal 133. The second upper switch assembly 1221 and the second lower switch assembly 1222 are connected in series. Another port of the node between the second upper switch assembly 1221 and the second lower switch assembly 1222 is led out and connected to the AC output terminal 134 to output an AC signal.

[0045] Please see Figure 3 and Figure 5In this embodiment, both the second upper switching assembly 1221 and the second lower switching assembly 1222 include five switching units T. The switching units T in the second upper switching assembly 1221 and their corresponding counterparts in the second lower switching assembly 1222 are connected in series to form a bridge arm 1201. The second inverter circuit 122 includes five bridge arms 1201 connected in parallel. Two switching units T in each bridge arm 1201 are arranged along a second direction and staggered along a first direction to reduce thermal coupling between the two switching units T. It can be understood that by staggering the positions of the two series-connected switching units T in the bridge arm 1201, thermal coupling between the switching units T can be reduced, thereby reducing the junction temperature of the switching units T in the power module 100 and improving the performance of the power module 100.

[0046] Please refer to the following: Figure 2 and Figure 3 The first upper switch assembly 1211 and the second upper switch assembly 1221 are symmetrically arranged. The first lower switch assembly 1212 and the second lower switch assembly 1222 are also symmetrically arranged. The first lower switch assembly 1212 is closer to the negative power terminal 133 than the first upper switch assembly 1211, allowing the first lower switch assembly 1212 to be connected to the negative power terminal 133 via a shorter bonding wire, thereby reducing the parasitic inductance of the trace. The second lower switch assembly 1222 is also closer to the negative power terminal 133 than the second upper switch assembly 1221, allowing the second lower switch assembly 1222 to be connected to the negative power terminal 133 via a shorter bonding wire, thereby reducing the parasitic inductance of the trace. Specifically, the printed circuit board 110 has a solder mask layer, the negative power terminal 133 is soldered to this solder mask layer, and the first lower switch assembly 1212 and the second lower switch assembly 1222 are connected to this solder mask layer via bonding wires, thereby achieving connection with the negative power terminal 133.

[0047] Optionally, the switching unit T can be a silicon carbide MOSFET. Silicon carbide MOSFETs have advantages such as higher voltage rating, better high-frequency characteristics, high temperature resistance, and low switching and conduction losses.

[0048] Furthermore, please refer to the following: Figure 2 , Figure 3 , Figure 4 and Figure 5The signal terminal set 140 may include, but is not limited to, an upper switch drive lead-out terminal 141, a lower switch drive lead-out terminal 142, a first Kelvin source lead-out terminal 143, and a second Kelvin source lead-out terminal 144. The upper switch drive lead-out terminal 141, the lower switch drive lead-out terminal 142, the first Kelvin source lead-out terminal 143, and the second Kelvin source lead-out terminal 144 are electrically connected to the printed circuit board 110. The upper switch drive lead-out terminal 141 (G1) is used to input the drive signal for driving the switch unit T in the first upper switch assembly 1211 and the second upper switch assembly 1221. The lower switch drive lead-out terminal 142 (G2) is used to input the drive signal for driving the switch unit T in the first lower switch assembly 1212 and the second lower switch assembly 1222. The first Kelvin source lead-out terminal 143 (S1) is used to connect to the drive circuit for driving the switch unit T in the first upper switch assembly 1211 and the second upper switch assembly 1221. The second Kelvin source terminal 144 (S2) is used to connect the drive circuit that drives the switching unit T in the first lower switch assembly 1212 and the second lower switch assembly 1222. The upper switch drive terminal 141 and the lower switch drive terminal 142 are located on both sides of the AC output terminal 134, respectively. The upper switch drive terminal 141 is closer to the second inverter circuit 122 than the lower switch drive terminal 142. The first Kelvin source terminal 143 is located between the upper switch drive terminal 141 and the AC output terminal 134. The second Kelvin source terminal 144 is located between the lower switch drive terminal 142 and the AC output terminal 134.

[0049] Furthermore, please refer to the following: Figure 3 , Figure 6 and Figure 7 , Figure 6 yes Figure 2 A schematic diagram of the structure of a printed circuit board according to an embodiment. Figure 7 yes Figure 6 The printed circuit board 110 is a front view of the circuit board. The printed circuit board 110 may include, but is not limited to, an upper switch drive signal bus 111, a lower switch drive signal bus 112, an upper switch Kelvin source bus 113, a lower switch Kelvin source bus 114, a substrate layer 115, and a conductive layer 116. The upper switch drive signal bus 111, lower switch drive signal bus 112, upper switch Kelvin source bus 113, and lower switch Kelvin source bus 114 are located on the side of the substrate layer 115 facing the inverter circuit 120. The conductive layer 116 is located on the other side of the substrate layer 115 away from the inverter circuit 120.

[0050] Furthermore, please refer to the following: Figure 2 and Figure 3The upper switch drive signal bus 111 includes a first upper switch drive bus 1111 and a second upper switch drive bus 1112. The first upper switch drive bus 1111 is located between the first upper switch assembly 1211 and one edge of the printed circuit board 110 along a first direction. The second upper switch drive bus 1112 is located between the second upper switch assembly 1221 and the other edge of the printed circuit board 110 along the first direction. The first upper switch drive bus 1111 is connected to the second upper switch drive bus 1112 via a bonding wire. In this embodiment, since the distance between the first upper switch drive bus 1111 and the second upper switch drive bus 1112 is relatively large, the first upper switch drive bus 1111 and the second upper switch drive bus 1112 are connected by a two-stage jumper to reduce the length of a single bonding wire, thereby ensuring the reliability of the connection and reducing the difficulty of production. The second upper switch drive bus 1112 is connected to the upper switch drive lead-out terminal 141. The lower switch drive signal bus 112 is located between the first lower switch assembly 1212 and the second lower switch assembly 1222. The lower switch drive signal bus 112 is connected to the lower switch drive lead-out terminal 142 via a bonding wire.

[0051] Furthermore, please refer to the following: Figure 2 , Figure 3 , Figure 4 and Figure 5 The control terminal (gate) of each switching unit T in the first upper switching assembly 1211 is connected to the first upper switch drive bus 1111 via a bonding wire. The control terminal (gate) of each switching unit T in the second upper switching assembly 1221 is connected to the second upper switch drive bus 1112 via a bonding wire. Therefore, the drive signal can simultaneously drive the switching units T in the first upper switching assembly 1211 and the second upper switching assembly 1221 through the upper switch drive lead-out terminal 141 to increase the current carrying capacity.

[0052] The control terminal (gate) of each switching unit T in the first lower switching assembly 1212 and the second lower switching assembly 1222 is connected to the lower switching drive signal bus 112 via a bonding wire. Therefore, the drive signal can simultaneously drive the switching units T in the first lower switching assembly 1212 and the second lower switching assembly 1222 through the lower switching drive lead-out terminal 142 to increase the current carrying capacity. Note that the two switching units T in each bridge arm 1201 of the first inverter circuit 121 and the second inverter circuit 122 are not simultaneously turned on.

[0053] Furthermore, please refer to the following: Figure 2 , Figure 3 and Figure 4The upper switch Kelvin source busbar 113 includes a first upper switch Kelvin busbar 1131 and a second upper switch Kelvin busbar 1132. The first upper switch Kelvin busbar 1131 is located between the first upper switch drive busbar 1111 and the first upper switch assembly 1211. The first upper switch Kelvin busbar 1131 is connected to the second upper switch Kelvin busbar 1132 via a bonding wire. In this embodiment, since the distance between the first upper switch Kelvin busbar 1131 and the second upper switch Kelvin busbar 1132 is relatively large, the first upper switch Kelvin busbar 1131 and the second upper switch Kelvin busbar 1132 are connected by a two-stage jumper to reduce the length of a single bonding wire, thereby ensuring the reliability of the connection and reducing the difficulty of production. The second upper switch Kelvin busbar 1132 is connected to the first Kelvin source lead-out terminal 143. The lower switch Kelvin source bus 114 is located between the lower switch drive signal bus 112 and the second lower switch assembly 1222. The lower switch Kelvin source bus 114 is connected to the second Kelvin source lead-out terminal 114 via a bonding wire.

[0054] In this configuration, the source of each switching unit T in the first upper switching assembly 1211 is connected to the first upper switching Kelvin busbar 1131. The source of each switching unit T in the second upper switching assembly 1221 is connected to the second upper switching Kelvin busbar 1132. Therefore, when the first Kelvin source terminal 143 is connected to the drive circuit driving the switching units T in the first upper switching assembly 1211 and the second upper switching assembly 1221, separating the drive circuit and power circuit of the switching unit T, the switching units T in the first upper switching assembly 1211 and the second upper switching assembly 1221 can be turned on and / or turned off more quickly, thereby reducing losses and crosstalk.

[0055] The source of each switching unit T in the first lower switching assembly 1212 and the second lower switching assembly 1222 is connected to the lower switch Kelvin source bus 114. Therefore, when the second Kelvin source lead-out terminal 144 is connected to the drive circuit driving the switching unit T in the first lower switching assembly 1212 and the second lower switching assembly 1222, separating the drive circuit and power circuit of the switching unit T, the switching unit T in the first lower switching assembly 1212 and the second lower switching assembly 1222 can be turned on and / or turned off faster, thereby reducing losses and crosstalk.

[0056] Optionally, the substrate layer 115 is a silicon nitride ceramic layer. Silicon nitride ceramic layers are not only insulating but also have excellent thermal conductivity.

[0057] Optionally, the conductive layer 116 is a copper-clad layer. The copper-clad layer not only conducts electricity but also has excellent thermal conductivity.

[0058] Please refer to the following: Figure 2 and Figure 3In one embodiment, the power module 100 further includes a thermistor 170. The signal terminal set 140 further includes a first temperature sensing lead-out terminal 145 and a second temperature sensing lead-out terminal 146. The thermistor 170 is disposed on the printed circuit board 110 and located between the first upper switch assembly 1211 and the first upper switch Kelvin busbar 1131, so that the measured temperature is closer to the actual temperature of the switch unit T. The first temperature sensing lead-out terminal 145 and the second temperature sensing lead-out terminal 146 are located between the lower switch drive lead-out terminal 142 and one edge of the printed circuit board 110 along a first direction.

[0059] Optionally, the thermistor 170 can be a platinum resistance thermometer. Platinum resistance thermometers offer higher measurement accuracy and a wider measurement range compared to other thermistors.

[0060] Please refer to the following: Figure 2 and Figure 3 In one embodiment, the signal terminal set 140 further includes a sampling signal output terminal 147. The sampling signal output terminal 147 is located between the upper switch drive output terminal 141 and the other edge of the printed circuit board 110 along a first direction. A second positive power terminal 132 is connected to the sampling signal output terminal 147 via a bonding wire. The sampling signal output terminal 147 is used to output a sampling signal of an externally input AC signal to monitor changes in the externally input AC signal.

[0061] Please see Figure 8 , Figure 8 This is a flowchart illustrating an embodiment of the power module fabrication method provided in this application. The power module fabrication method 200 may include, but is not limited to, the following steps:

[0062] S210: A circuit layer is fabricated on a substrate layer using UV curing and etching processes to obtain a printed circuit board.

[0063] Specifically, the circuit layer may include, but is not limited to, the upper switch drive signal bus 111, the lower switch drive signal bus 112, the upper switch Kelvin source bus 113, and the lower switch Kelvin source bus 114. In other embodiments, the circuit layer also includes a solder mask layer for soldering and fixing the power terminal set 130 and the signal terminal set 140. First, a photosensitive material is coated on the substrate layer 115, then the substrate layer 115 coated with the photosensitive material is exposed to UV light under a special mask (UV curing), and finally the unexposed photosensitive material is washed away with a developer (etching), thus obtaining the circuit layer on the substrate layer 115, thereby obtaining the printed circuit board 110. In other embodiments, a copper-clad layer may also be formed on the side of the substrate layer 115 opposite to the plane where the circuit layer is located.

[0064] S220: On a printed circuit board, the switching unit, power terminals and signal lead-out terminals are fixed in preset positions according to a preset layout to obtain the first semi-finished product.

[0065] Specifically, the switching unit T is a silicon carbide MOSFET. The power terminals are a power terminal set 130, including a first positive power terminal 131, a second positive power terminal 132, a negative power terminal 133, and an AC output terminal 134. The signal output terminals are a signal terminal set 140, including an upper switch drive output terminal 141, a lower switch drive output terminal 142, a first Kelvin source output terminal 143, and a second Kelvin source output terminal 144. In some other embodiments, the signal output terminals also include a first temperature sensing output terminal 145, a second temperature sensing output terminal 146, and a sampling signal output terminal 147. After the printed circuit board 110 is fabricated, the switching unit T, power terminals, and signal output terminals are arranged according to… Figure 2 and Figure 3 The layout is fixed at the corresponding position on the circuit layer of the printed circuit board 110.

[0066] S230: The first semi-finished product is fixed to the heat dissipation device by welding process to obtain the second semi-finished product.

[0067] Specifically, the first semi-finished product is placed in a nitrogen atmosphere, and the printed circuit board 110 in the first semi-finished product is soldered and fixed to the heat dissipation device 150 through a soldering process. The heat dissipation device 150 is a pin-fin water-cooled radiator.

[0068] S240: The second semi-finished product is placed in a mold and the encapsulation shell is made by injection molding to obtain the power module.

[0069] Specifically, the second semi-finished product is placed in a specially made mold, and then molten resin is poured into the mold. After the resin cools and solidifies, the encapsulation housing 160 is obtained. The encapsulation housing 160 seals the printed circuit board 110, the switching unit T, some power terminals, some signal lead-out terminals, and some heat dissipation device 150.

[0070] Please see Figure 9 , Figure 9 yes Figure 8 A flowchart illustrating an embodiment of step S220. Step S220 may include, but is not limited to, the following steps:

[0071] S221: On the printed circuit board, the switch unit is soldered to the preset position according to the preset layout through the soldering process, completing the first process.

[0072] Specifically, after the printed circuit board 110 is manufactured, it is then processed according to... Figure 3In this layout, the pins of the switching unit T are soldered to their relative positions on the circuit layer 110 of the printed circuit board under a nitrogen atmosphere, completing the first process.

[0073] S222: Based on the first process, the power terminals and signal lead-out terminals are fixed in the preset positions according to the preset layout by ultrasonic bonding process to complete the second process.

[0074] Specifically, after completing the first process, the power terminals and signal output terminals are arranged according to... Figure 2 The layout is such that the components are bonded to the corresponding positions on the 110 circuit layer of the printed circuit board using ultrasonic bonding technology, thus completing the second process.

[0075] S223: Based on the second process, the control terminal and Kelvin source of the switching unit are fixed in the preset position according to the preset layout by ultrasonic bonding process to obtain the first semi-finished product.

[0076] Specifically, after completing the second process, the control terminal (gate) and Kelvin source of each switching unit T are connected according to... Figure 3 The layout is such that the components are bonded to the corresponding positions of the circuit layer 110 of the printed circuit board using an ultrasonic bonding process, thus obtaining the first semi-finished product.

[0077] The power module 100 provided in this application includes: a printed circuit board 110; and an inverter circuit 120 electrically connected to the printed circuit board 110 for converting an externally input DC signal into an AC signal, comprising: a first inverter circuit 121 disposed on one side of the printed circuit board 110 along a first direction; and a second inverter circuit 122 disposed on the other side of the printed circuit board 110 along the first direction. The first inverter circuit 121 and the second inverter circuit 122 are connected in parallel and symmetrically arranged to reduce the parasitic inductance of the power module 100. Through this method, the power module 100 can reduce the parasitic inductance of the traces, thereby avoiding large voltage overshoot and electromagnetic interference during the operation of the inverter circuit 120.

[0078] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A power module, characterized in that, include: The power module further includes a first positive power terminal, a second positive power terminal, a negative power terminal, and an AC output terminal. The first positive power terminal, the second positive power terminal, the negative power terminal, and the AC output terminal are electrically connected to the printed circuit board. The first positive power terminal and the second positive power terminal are located on opposite sides of the negative power terminal. An inverter circuit, electrically connected to the printed circuit board, is used to convert an externally input DC signal into an AC signal, including: A first inverter circuit is disposed on one side of the printed circuit board along a first direction. The first inverter circuit includes a first upper switch assembly and a first lower switch assembly. One end of the first upper switch assembly is connected to the first positive power terminal; one end of the first lower switch assembly is connected to the negative power terminal. The first upper switch assembly and the first lower switch assembly are connected in series. A port is led out from the node between the first upper switch assembly and the first lower switch assembly and connected to the AC output terminal to output the AC signal. A second inverter circuit is disposed on the other side of the printed circuit board along the first direction. The second inverter circuit includes a second upper switch assembly and a second lower switch assembly. One end of the second upper switch assembly is connected to the second positive power terminal; one end of the second lower switch assembly is connected to the negative power terminal. The second upper switch assembly and the second lower switch assembly are connected in series. The node between the second upper switch assembly and the second lower switch assembly has another port connected to the AC output terminal to output the AC signal. The first inverter circuit and the second inverter circuit are connected in parallel and symmetrically arranged to reduce the parasitic inductance of the power module. The power module further includes an upper switch drive lead-out terminal and a lower switch drive lead-out terminal, which are electrically connected to the printed circuit board. The upper switch drive lead-out terminal and the lower switch drive lead-out terminal are located on both sides of the AC output terminal, and the upper switch drive lead-out terminal is closer to the second inverter circuit than the lower switch drive lead-out terminal.

2. The power module according to claim 1, characterized in that, The first positive power terminal, the second positive power terminal, and the negative power terminal are disposed on one side of the printed circuit board along the second direction, and the AC output terminal is disposed on the other side of the printed circuit board along the second direction. The first upper switch assembly and the second upper switch assembly are symmetrically arranged, and the first lower switch assembly and the second lower switch assembly are symmetrically arranged; The first inverter circuit is closer to the first positive power terminal than the second inverter circuit, the first lower switch assembly is closer to the negative power terminal than the first upper switch assembly, and the second lower switch assembly is closer to the negative power terminal than the second upper switch assembly. The second direction is perpendicular to the first direction.

3. The power module according to claim 2, characterized in that, The printed circuit board includes: The upper switch drive signal bus includes a first upper switch drive bus and a second upper switch drive bus. The first upper switch drive bus is located between the first upper switch assembly and one edge of the printed circuit board along the first direction. The second upper switch drive bus is located between the second upper switch assembly and the other edge of the printed circuit board along the first direction. The first upper switch drive bus is connected to the second upper switch drive bus via a bonding wire. The second upper switch drive bus is connected to the upper switch drive lead-out terminal. The lower switch drive signal bus is located between the first lower switch assembly and the second lower switch assembly, and the lower switch drive signal bus is connected to the lower switch drive lead-out terminal through a bonding wire.

4. The power module according to claim 3, characterized in that, The first upper switch assembly, the first lower switch assembly, the second upper switch assembly, and the second lower switch assembly each include multiple switch units; The control terminal of each of the switching units in the first upper switch assembly is connected to the first upper switch drive bus via a bonding wire. The control terminal of each of the switching units in the second upper switch assembly is connected to the second upper switch drive bus via a bonding wire. The control terminal of each of the switching units in the first lower switch assembly and the second lower switch assembly is connected to the lower switch drive signal bus via a bonding wire.

5. The power module according to claim 4, characterized in that, The switching unit is a silicon carbide MOS transistor.

6. The power module according to claim 5, characterized in that, The power module further includes a first Kelvin source terminal and a second Kelvin source terminal, which are electrically connected to the printed circuit board. The first Kelvin source terminal is located between the upper switch drive terminal and the AC output terminal, and the second Kelvin source terminal is located between the lower switch drive terminal and the AC output terminal. The printed circuit board also includes: The upper switch Kelvin source busbar includes a first upper switch Kelvin busbar and a second upper switch Kelvin busbar. The first upper switch Kelvin busbar is located between the first upper switch drive busbar and the first upper switch assembly. The first upper switch Kelvin busbar is connected to the second upper switch Kelvin busbar through a bonding wire. The second upper switch Kelvin busbar is connected to the first Kelvin source lead-out terminal. The lower switch Kelvin source busbar is located between the lower switch drive signal busbar and the second lower switch assembly. The lower switch Kelvin source busbar is connected to the second Kelvin source lead-out terminal via a bonding wire. In this configuration, the source of each switch unit in the first upper switch assembly is connected to the first upper switch Kelvin busbar, the source of each switch unit in the second upper switch assembly is connected to the second upper switch Kelvin busbar, and the source of each switch unit in the first lower switch assembly and the second lower switch assembly is connected to the lower switch Kelvin source busbar.

7. The power module according to claim 4, characterized in that, The first upper switch assembly, the first lower switch assembly, the second upper switch assembly, and the second lower switch assembly each include five of the aforementioned switch units.

8. The power module according to claim 6, characterized in that, The power module further includes a thermistor, a first temperature sensing lead-out terminal, and a second temperature sensing lead-out terminal. The thermistor is disposed on the printed circuit board and is located between the first upper switch assembly and the first upper switch Kelvin busbar. The first temperature sensing lead-out terminal and the second temperature sensing lead-out terminal are located between the lower switch drive lead-out terminal and one edge of the printed circuit board along the first direction.

9. The power module according to claim 8, characterized in that, The thermistor is a platinum resistance thermometer.

10. The power module according to claim 6, characterized in that, The power module further includes a sampling signal lead-out terminal, which is located between the upper switch drive lead-out terminal and the other edge of the printed circuit board along the first direction. The second positive power terminal is connected to the sampling signal lead-out terminal via a bonding wire.

11. The power module according to claim 6, characterized in that, The printed circuit board further includes a substrate layer and a conductive layer. The upper switch drive signal bus, the lower switch drive signal bus, the upper switch Kelvin source bus, and the lower switch Kelvin source bus are located on the side of the substrate layer facing the inverter circuit, and the conductive layer is located on the other side of the substrate layer away from the inverter circuit.

12. The power module according to claim 11, characterized in that, The substrate layer is a silicon nitride ceramic layer, and the conductive layer is a copper-clad layer.

13. The power module according to claim 1, characterized in that, The power module also includes a heat dissipation device, which is fixed to the printed circuit board.

14. The power module according to claim 13, characterized in that, The heat dissipation device is a needle-fin water-cooled radiator.

15. The power module according to claim 1, characterized in that, The power module also includes a housing for sealing the inverter circuit and the printed circuit board.

16. The power module according to claim 1, characterized in that, Both the first inverter circuit and the second inverter circuit include multiple parallel bridge arms, each of which includes two switching units connected in series. The two switching units are arranged along a second direction and staggered along the first direction to reduce thermal coupling between the two switching units; wherein the second direction is perpendicular to the first direction.

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