Inverter device

Abstract

The present invention provides an inverter device that can more effectively reduce the impact of noise from switching elements on the drive circuit. [Solution] The control board 38 on which the drive circuit is mounted is configured as a multilayer board. A control board module including the control board 38 and a main circuit module including a main circuit on which switching elements are mounted are integrated in the stacking direction of the multilayer board. A high-voltage circuit GND pattern 40 and a low-voltage circuit GND pattern 42 are provided separately on the same layer of the control board 38. In the control board 38, a low-voltage circuit GND layer 44 having a low-voltage circuit GND that is conductive with the low-voltage circuit GND pattern 40 is provided in a layer located between the layer on which the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 are arranged and the main circuit module.

Description

Technical Field

[0001] The present disclosure relates to an inverter device in which a main circuit module including a main circuit on which switching elements constituting an inverter are mounted and a control board module including a control board on which a drive circuit for outputting a drive signal for driving the switching elements are integrated.

Background Art

[0002] For example, Patent Document 1 describes an inverter-integrated electric compressor. This inverter-integrated electric compressor is provided with an inverter housing portion for housing an inverter device on the outer periphery of a housing. The inverter device includes a power circuit board on which semiconductor switching elements and the like are mounted, and a control board on which control and communication circuits operating at a low voltage are mounted. And, in the upper space of the power circuit board and the control board, a high-voltage bus bar for connecting between a high-voltage line and high-voltage components such as a smoothing capacitor, an inductor coil, and a common-mode coil is disposed. Further, in order to reduce electromagnetic noise interference from the high-voltage bus bar, a shield plate is disposed between the high-voltage bus bar and the inverter module.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inverter device of Patent Document 1 integrally modularizes a power circuit board on which a plurality of power semiconductor switching elements and a power system control circuit (hereinafter also referred to as a drive circuit or a gate driver) for operating the same are mounted, and a control board on which elements operating at a low voltage such as a CPU are mounted, and is configured in a substantially rectangular parallelepiped shape.

[0005] Here, when the power semiconductor switching element is turned on and off, magnetic field noise and electric field noise are radiated from the power semiconductor switching element. To reduce the influence of magnetic field noise and electric field noise on the power control circuit, instead of mounting both the power semiconductor switching element and the power control circuit on the power circuit board, it is conceivable to mount the power semiconductor switching element on the power circuit board and the power control circuit on the control board.

[0006] The power control circuit includes a high-voltage circuit section that applies a gate drive signal (drive voltage) to the gate of a power semiconductor switching element and discharges the voltage charged to the gate of the power semiconductor switching element. The power control circuit also includes a low-voltage circuit section for controlling the switching element that generates the gate drive signal. Therefore, when the power control circuit is mounted on a control board, the control board is provided with a high-voltage circuit GND pattern for the high-voltage circuit and a low-voltage circuit GND pattern for the low-voltage circuit in the drive circuit. These high-voltage circuit GND patterns and low-voltage circuit GND patterns, interposed between the power control circuit and the power semiconductor switching element, play a certain role in reducing the influence of magnetic field noise and electric field noise on the power control circuit.

[0007] However, high-voltage circuit GND patterns and low-voltage circuit GND patterns must be provided separately for insulation. Therefore, there is a concern that magnetic field noise and electric field noise may leak through the gap between the high-voltage circuit GND patterns and the low-voltage circuit GND patterns, affecting the operation of power control circuits.

[0008] This disclosure has been made in view of the above-mentioned points, and aims to provide an inverter device that can more effectively reduce the influence of noise from switching elements to the drive circuit when a main circuit module including a main circuit on which switching elements constituting the inverter are mounted and a control board module including a control board on which a drive circuit for outputting drive signals for driving the switching elements are executed are integrated. [Means for solving the problem]

[0009] To achieve the above objectives, the inverter device according to this disclosure is: A main circuit module (23) including a main circuit (22) on which switching elements (16UH, 16UL, 18VH, 18VL, 20WH, 20WL) constituting the inverter are mounted, The system includes a control board module (39) which includes a control board (38) on which drive circuits (24, 26, 28, 30, 32) that output drive signals for driving switching elements are mounted, The control board is a multilayer board. The main circuit module and the control board module are integrated in the stacking direction of the multilayer substrate. On the same layer of the control board, a high-voltage circuit GND pattern (40) for the high-voltage circuit in the drive circuit and a low-voltage circuit GND pattern (42) for the low-voltage circuit in the drive circuit are provided separately. In a layer separate from the layer on which the high-voltage circuit GND pattern and the low-voltage circuit GND pattern are arranged, and located between the layer on which the high-voltage circuit GND pattern and the low-voltage circuit GND pattern are arranged and the main circuit module, at least one of the following is provided: a low-voltage circuit GND layer (44, 44A, 44B) having a low-voltage circuit GND that is conductive to the low-voltage circuit GND pattern, and a high-voltage circuit GND layer (46) having a high-voltage circuit GND that is conductive to the high-voltage circuit GND pattern.

[0010] With the above configuration, noise radiated from the switching elements constituting the inverter is shielded by the low-voltage circuit GND of the low-voltage circuit GND layer and / or the high-voltage circuit GND of the high-voltage circuit GND layer in the stacking direction of the multilayer substrate. Therefore, it is possible to more effectively reduce the impact of noise from the switching elements constituting the inverter on the drive circuit.

[0011] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in embodiments described later, in order to facilitate understanding of this disclosure, and are not intended to limit the scope of this disclosure in any way.

[0012] Furthermore, technical features described in each claim of the patent claims, other than those described above, will become clear from the description of the embodiments and the accompanying drawings, which will be discussed later. [Brief explanation of the drawing]

[0013] [Figure 1] This is a configuration diagram showing an example of the configuration of an inverter device according to the embodiment. [Figure 2] This diagram shows an example of a configuration where the main circuit module and the control board module are integrated. [Figure 3] This diagram shows a detailed view of a part of the control board module. [Figure 4] This figure shows examples of high-voltage circuit GND patterns and low-voltage circuit GND patterns. [Figure 5] This figure shows an example of a low-voltage circuit GND layer. [Figure 6] This graph shows the maximum measured magnetic field values ​​for both the example and the comparative example. [Figure 7] This graph shows the maximum measured electric field values ​​for both the example and the comparative example. [Figure 8] This diagram shows a detailed view of a part of the control board module, based on a modified example. [Modes for carrying out the invention]

[0014] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. For the same or similar configurations, the same reference numerals may be given across multiple drawings, and the description may be omitted. When only a part of the configuration is described in each embodiment, the configurations of other embodiments described previously can be applied to other parts of the said configuration. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of multiple embodiments can be partially combined with each other as long as there is no problem with the combination.

[0015] (First Embodiment) The inverter device according to this embodiment can be used, for example, to drive an electric motor as a drive source of a moving body. The moving body is, for example, an electric vehicle (BEV), a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), or other electric vehicles, an electric flying body such as a drone or an electric vertical takeoff and landing aircraft (eVTOL), a ship, a construction machine, or an agricultural machine. However, the electric motor driven by the inverter device according to this embodiment is not limited to an electric motor as a drive source of a moving body, and may be, for example, an electric motor that drives a compressor of an air conditioner. Thus, the inverter device according to this embodiment can be applied to an electric motor that needs to pass a large current to obtain a high output.

[0016] In FIG. 1, the electric motor 50 is, for example, a rotating electric machine of a three-phase alternating current system. FIG. 1 shows an example in which U-phase coils, V-phase coils, and W-phase coils are Y-connected. The U-phase coils, V-phase coils, and W-phase coils may be Δ-connected. The electric motor 50 functions, for example, as a driving source for the vehicle to travel, that is, as an electric motor. In this case, the electric motor 50 generates torque for driving drive wheels (not shown). Further, the electric motor 50 may function as a generator that generates regenerative power during vehicle braking.

[0017] FIG. 1 shows an example of the configuration of an inverter device 10 according to this embodiment. The inverter device 10 shown in FIG. 1 includes a high-voltage battery 12, a smoothing capacitor 14, a main circuit 22 on which switching elements 16UH, 16UL, 18VH, 18VL, 20WH, 20WL constituting an inverter are mounted, and control boards 38 on which drive circuits 24, 26, 28, 30, 32, 34 for outputting gate drive signals for driving the switching elements 当該スイッチング素子16UH、16UL、18VH、18VL、20WH、20WLを駆動するためのゲート駆動信号を出力する駆動回路24、26、28、30、32、34などが実装されている。インバータ装置10は、電力変換回路として、高圧バッテリ12から供給される直流電力を交流電力に変換して、電動モータ50へ出力する。また、電動モータ50が回生電力を発生したとき、インバータ装置10は、交流電力を直流電力に変換して、高圧バッテリ12に出力することができる。これにより、高圧バッテリ12は、充電され得る。

[0018] Although not shown in FIG. 1, the power conversion circuit may have a boost circuit between the high-voltage battery 12 and the smoothing capacitor 14. In this case, the smoothing capacitor 14 can be charged with a voltage higher than the DC voltage of the high-voltage battery 12 boosted by the boost circuit. Also, when used in a moving body such as a vehicle, the power conversion circuit may include a power supply switch (not shown) such as an SMR between the high-voltage battery 12 and the power conversion circuit. SMR is an abbreviation for System Main Relay. In this case, power supply from the high-voltage battery 12 to the electric motor 50 becomes possible when the power supply switch is turned on, and power supply from the high-voltage battery 12 to the electric motor 50 is cut off when the power supply switch is turned off.

[0019] The high-voltage battery 12 is constituted by, for example, a rechargeable secondary battery. The rechargeable secondary battery can be, for example, a lithium-ion battery, a nickel-metal hydride battery, or the like. For example, when used in a vehicle, the DC voltage generated by the high-voltage battery 12 is set higher than the DC voltage generated by an auxiliary battery (not shown).

[0020] The inverter device 10, which is a power conversion circuit, includes a high-potential power line 11 and a low-potential power line 13. The high-potential power line 11 is connected to the positive terminal of the high-voltage battery 12. The low-potential power line 13 is connected to the negative terminal of the high-voltage battery 12. The low-potential power line 13 is sometimes referred to as the earth line or ground line.

[0021] The smoothing capacitor 14 is connected between the high-potential power line 11 and the low-potential power line 13. The smoothing capacitor 14 is connected in parallel to the main circuit 22 on which the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL that constitute the inverter are mounted. The smoothing capacitor 14 smooths the DC voltage supplied by the high-voltage battery 12 or the DC voltage boosted by the boost circuit. The voltage across the smoothing capacitor 14 becomes the high DC voltage required to drive the electric motor 50.

[0022] Multiple switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL of the main circuit 22 constitute an inverter. As described above, the inverter of the main circuit 22 converts DC voltage to three-phase AC voltage and outputs it to the electric motor 50. In addition, the inverter of the main circuit 22 converts the three-phase AC voltage generated by the electric motor 50 in response to rotational force from the wheels during regenerative braking of the vehicle into DC voltage. In this way, the inverter of the main circuit 22 is capable of bidirectional power conversion between the high-voltage battery 12 and the electric motor 50. The inverter of the main circuit 22 is configured with upper and lower arm circuits for the U-phase, V-phase, and W-phase.

[0023] Each of the three phase upper and lower arm circuits has an upper arm and a lower arm. The upper and lower arms are connected in series between the high-potential power line 11 and the low-potential power line 13, with the upper arm on the high-potential power line 11 side. The connection points of the upper and lower arms are connected to the windings of the corresponding phases in the electric motor 50 via output lines 16, 18, and 20.

[0024] The upper arm has switching elements 16UH, 18VH, and 20WH, respectively. The lower arm has switching elements 16UL, 18VL, and 20WL, respectively. The number of switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL in each arm is not particularly limited. There may be one or more. In the case of multiple elements, the multiple switching elements connected in parallel are driven on or off at the same timing by a common gate drive signal (drive voltage).

[0025] The switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL shown in Figure 1 are all n-channel MOSFETs. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. Each of the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL has a freewheeling diode connected in antiparallel. That is, the anode terminal of the freewheeling diode is connected to the source terminal of the corresponding MOSFET, and the cathode terminal is connected to the drain terminal. The freewheeling diode may be a parasitic diode (body diode) of the MOSFET, or it may be a separate diode.

[0026] Note that the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL are not limited to MOSFETs. For example, the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL may be IGBTs. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of IGBTs, a freewheeling diode is also connected in antiparallel.

[0027] The control board 38 is equipped with drive circuits 24, 26, 28, 30, 32, and 34, and a control circuit 36. The control circuit 36 ​​generates drive commands to operate the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL, and outputs them to the drive circuits 24, 26, 28, 30, 32, and 34. In other words, the control circuit 36 ​​controls the operation of the drive circuits 24, 26, 28, 30, 32, and 34 based on the drive commands. The control circuit 36 ​​generates drive commands based on, for example, torque requests input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit.

[0028] Various sensors include, for example, current sensors, rotation angle sensors, voltage sensors, and temperature sensors. The current sensor detects the phase current flowing through the windings of each phase of the electric motor 50. The rotation angle sensor detects the rotation angle of the rotor of the electric motor 50. The voltage sensor detects the voltage across the smoothing capacitor 14. The control circuit 36 ​​outputs a drive command, for example, a PWM signal. PWM is an abbreviation for Pulse Width Modulation.

[0029] The control circuit 36 ​​may consist of, for example, a processor, memory, and storage. The processor performs various processes by accessing the memory. The processor may include at least one of the following: a CPU, GPU, RISC-CPU, DFP, GSP, etc. CPU is an abbreviation for Central Processing Unit. GPU is an abbreviation for Graphics Processing Unit. RISC is an abbreviation for Reduced Instruction Set Computer. DFP is an abbreviation for Data Flow Processor. GSP is an abbreviation for Graph Streaming Processor.

[0030] Memory is a volatile storage medium, such as RAM. RAM stands for Random Access Memory. Storage is a non-transitional, tangible recording medium that stores programs executed by a processor. Storage is a rewritable, non-volatile storage medium, such as ROM or flash memory. ROM stands for Read Only Memory.

[0031] The processing performed by the control circuit 36 ​​can be implemented by software processing, where the processor executes the program described above. Alternatively, the processing performed by the control circuit 36 ​​may be implemented by hardware processing using dedicated electronic circuits such as ASICs or FPGAs. ASIC stands for Application Specific Integrated Circuit. FPGA stands for Field-Programmable Gate Array. Furthermore, the processing performed by the control circuit 36 ​​may be implemented by a combination of software and hardware processing. The control circuit 36 ​​can be packaged as a control IC and mounted on the surface layer of the control board 38.

[0032] The drive circuits 24, 26, 28, 30, 32, and 34 supply drive signals (drive voltages) to the gates of the corresponding arm switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL based on the drive command from the control circuit 36. These drive signals either turn the corresponding switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL on or off.

[0033] The drive circuits 24, 26, 28, 30, 32, and 34 can be configured, for example, by push-pull transistor circuits. More specifically, the drive circuits 24, 26, 28, 30, 32, and 34 can be configured, for example, by connecting a p-channel MOSFET and an n-channel MOSFET in series. A common drive command (PWM signal) from the control circuit 36 ​​is input to the gates of the two MOSFETs. As a result, when the drive command turns on the p-channel MOSFET, the n-channel MOSFET turns off, and conversely, when the p-channel MOSFET turns off, the n-channel MOSFET turns on.

[0034] In the example above, when the p-channel MOSFET is turned on and the n-channel MOSFET is turned off, the gates of the corresponding arm's switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL can be connected to a power supply (not shown) via the p-channel MOSFET. On the other hand, when the p-channel MOSFET is turned off and the n-channel MOSFET is turned on, the gates of the corresponding arm's switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL can be connected to ground via the n-channel MOSFET. In this way, the gate capacitances of the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL are charged and discharged according to the drive signal. The switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL turn on when the gate voltage exceeds a threshold and turn off when it falls below the threshold.

[0035] Here, when the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL are switched on and off, ringing may occur in the current flowing through the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL, as well as in the drain-source voltage of the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL. When ringing occurs, magnetic field noise and electric field noise are radiated from the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL. Magnetic field noise generates noise current. Electric field noise, for example, causes the ground potential to oscillate. Therefore, in order for the drive circuits 24, 26, 28, 30, 32, 34 and the control circuit 36 ​​to operate normally, it is important to reduce the effects of magnetic field noise and electric field noise radiated from the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL.

[0036] In this embodiment, the inverter device 10 does not implement both the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, 20WL and the drive circuits 24, 26, 28, 30, 32, 34 on the main circuit 22 in order to reduce the influence of magnetic field noise and electric field noise on the drive circuits 24, 26, 28, 30, 32, 34. In this embodiment, the drive circuits 24, 26, 28, 30, 32, 34 are implemented on the control board 38 as described above.

[0037] Furthermore, in order to reduce the size of the inverter device 10 according to this embodiment, as shown in Figure 2, a main circuit module 23 including a main circuit 22 and a control board module 39 including a control board 38 are stacked and integrated in the Z direction. In the following, the stacking direction of the main circuit module 23 and the control board module 39 will be referred to as the Z direction. The direction perpendicular to the Z direction will be referred to as the X direction. The direction perpendicular to both the Z direction and the Y direction will be referred to as the Y direction. Thus, the X direction, Y direction and Z direction are in a positional relationship that is orthogonal to each other. The main circuit module 23 and the control board module 39 are arranged along the XY plane defined by the X direction and the Y direction.

[0038] The control circuit 36 ​​mounted on the control board 38 is configured to operate at a low voltage of, for example, 5V or less. Therefore, the drive commands (PWN signals) that the control circuit 36 ​​outputs to each of the drive circuits 24, 26, 28, 30, 32, and 34 are signals whose voltage level changes between, for example, 0V and 5V. The drive commands from the control circuit 36 ​​are transmitted, for example, to the gates of the MOSFETs that constitute the push-pull circuits of the drive circuits 24, 26, 28, 30, 32, and 34. Thus, the drive circuits 24, 26, 28, 30, 32, and 34 include low-voltage circuit portions such as circuits for transmitting drive commands from the control circuit 36. In Figure 1, the low-voltage circuit portion on the control board 38 is indicated by the reference numeral 38L. The control board 38 has a low-voltage circuit GND pattern 42 (see Figure 3) formed therein to provide a reference ground potential for the low-voltage circuits. The low-voltage circuit GND pattern 42 is then body-grounded to the vehicle body or other components via the low-voltage circuit ground wire 37.

[0039] Furthermore, the drive circuits 24, 26, 28, 30, 32, and 34 output drive signals to the gates of each switching element 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL that constitute the inverter. These drive signals are set to a high voltage (for example, several tens of volts) to enable each switching element 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL to supply a large current to the electric motor 50. Thus, the drive circuits 24, 26, 28, 30, 32, and 34 include a high-voltage circuit section that applies a high voltage to the gates of the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL, and discharges the applied high voltage. In Figure 1, the high-voltage circuit section of the control board 38 is indicated by the reference numeral 38H. The control board 38 has a high-voltage circuit GND pattern 40 (see Figure 3) formed therein to provide a reference ground potential to the high-voltage circuit. The high-voltage circuit GND pattern 40 is connected to the low-potential power line 13 via the high-voltage circuit ground line 35.

[0040] As described above, in the inverter device 10 according to this embodiment, drive circuits 24, 26, 28, 30, 32, and 34 are provided on the control board 38. Furthermore, the control board 38 is provided with a high-voltage circuit GND pattern 40 for the high-voltage circuit and a low-voltage circuit GND pattern 42 for the low-voltage circuit. These high-voltage circuit GND patterns 40 and low-voltage circuit GND patterns 42 are interposed between the drive circuits 24, 26, 28, 30, 32, and 34 and the control circuit 36 ​​and the main circuit 22 on which the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL are mounted, thereby playing a certain role in reducing the influence of magnetic field noise and electric field noise on the drive circuits 24, 26, 28, 30, 32, and 34 and the control circuit 36.

[0041] However, the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 must be provided separately on the control board 38 for insulation purposes, as shown in Figures 3 and 4. Figure 4 shows an example of each pattern when the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 are provided on the surface layer of the control board 38. As shown in Figure 4, a gap is provided between the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42, and this gap electrically insulates the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42.

[0042] In the examples shown in Figures 3 and 4, the drive circuits 24, 26, 28, 30, 32, and 34 are packaged as a drive IC and mounted on the surface of the control board 38. In this case, since the drive circuits 24, 26, 28, 30, 32, and 34 have a high-voltage circuit portion 38H and a low-voltage circuit portion 38L, the drive IC containing each drive circuit 24, 26, 28, 30, 32, and 34 is mounted on the control board 38 so as to straddle the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42. Connections to the drive IC other than the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 can be made via via holes formed directly beneath the drive IC.

[0043] Furthermore, in the example shown in Figure 4, the high-voltage circuit GND pattern 40 is separated for each drive IC. However, the high-voltage circuit GND pattern 40 may be common to multiple drive ICs. In addition, the control circuit 36 ​​is omitted in the example shown in Figure 4.

[0044] As shown in Figure 4, a gap is provided between the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42. Therefore, there is a concern that magnetic field noise and electric field noise may leak from the gap between the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42, affecting the operation of the drive circuits 24, 26, 28, 30, 32, 34 and the control circuit 36.

[0045] Therefore, in the inverter device 10 according to this embodiment, first, the control board 38 is configured as a multilayer board. Then, as shown in Figure 2, the control board module 39 and the main circuit module 23 are configured to be integrated in the stacking direction of the multilayer board (the Z direction in Figure 2). Furthermore, as shown in Figure 3, a high-voltage circuit GND pattern 40 and a low-voltage circuit GND pattern 42 are provided separately on the same layer of the multilayer board control board 38 (for example, the surface layer of the control board 38). In addition, in the control board 38, a low-voltage circuit GND layer 44 is provided on a layer separate from the layer on which the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 are arranged, and located between the layer on which the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 are arranged and the main circuit module 23, and which has a low-voltage circuit GND that is conductive with the low-voltage circuit GND pattern 42.

[0046] Figure 3 shows an example in which a low-voltage circuit GND layer 44, which has a low-voltage circuit GND that is conductive to the low-voltage circuit GND pattern 42, is provided in a layer located between the layer on which the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 are arranged and the main circuit module 23. However, instead of the low-voltage circuit GND layer 44, a high-voltage circuit GND layer having a high-voltage circuit GND that is conductive to the high-voltage circuit GND pattern 40 may be provided.

[0047] Furthermore, Figure 3 shows an example in which a high-voltage circuit GND pattern 40 and a low-voltage circuit GND pattern 42 are provided on the surface layer of the control board 38. By providing the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 on the surface layer of the control board 38 in this way, the distance to the drive IC is reduced, which helps to stabilize the ground potential of the high-voltage circuit portion 38H and the low-voltage circuit portion 38L. However, for example, a wiring pattern may be formed on the surface layer of the control board 38, and the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 may be provided in an inner layer separated by a single insulating layer.

[0048] With the above configuration, noise radiated from the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL of the main circuit 22 can be shielded by the low-voltage circuit GND of the low-voltage circuit GND layer 44 and / or the high-voltage circuit GND of the high-voltage circuit GND layer in the stacking direction of the multilayer substrate (Z direction in Figure 2). Therefore, the influence of magnetic field noise and electric field noise radiated from the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL on the drive circuits 24, 26, 28, 30, 32, 34 and the control circuit 36 ​​can be more effectively reduced.

[0049] The main circuit module 23 and the control board module 39 will be described in detail below with reference to the drawings.

[0050] The control board module 39 includes a control board 38, which is a multilayer substrate. The control board 38 is constructed by laminating multiple layers of insulating layers and wiring layers. The insulating layers are formed using electrically insulating materials such as resin. The insulating layers may be formed from an insulating substrate containing only resin, for example, or from a combination of resin and glass cloth, nonwoven fabric, etc. The wiring layers may be formed using a metal material with good conductivity, such as Cu. The wiring layers include conductor patterns. Conductor patterns may be referred to as wiring or wiring patterns. Conductor patterns may be formed, for example, by patterning metal foil or by printing. In addition to the conductor patterns of the wiring layers, the multilayer substrate may also include through-hole lands and via conductors. Through-hole lands are formed on the walls of through-holes that penetrate the multilayer substrate in the Z direction. Via conductors are formed by placing conductors such as pins or plating in through-holes (via holes) formed in the insulating layer. Via conductors electrically connect conductor patterns arranged in different layers.

[0051] In this embodiment, at least one wiring layer inside the multilayer substrate is a low-voltage circuit GND layer 44 having a low-voltage circuit GND that is conductive to the low-voltage circuit GND pattern 42 via a through-hole land, as shown in Figure 3. The low-voltage circuit GND of the low-voltage circuit GND layer 44 has a shape that seals the gap between at least the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42 in the stacking direction (Z direction) of the multilayer substrate. As a result, the low-voltage circuit GND of the low-voltage circuit GND layer 44 can effectively suppress magnetic field noise and electric field noise leaking from the gap between the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42.

[0052] Figure 5 shows an example of the low-voltage circuit GND of the low-voltage circuit GND layer 44. In the example shown in Figure 5, the low-voltage circuit GND of the low-voltage circuit GND layer 44 is generally formed as a solid plane pattern that covers most of the insulating layer. By forming the low-voltage circuit GND of the low-voltage circuit GND layer 44 as a solid plane pattern in this way, noise radiated from the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL of the main circuit 22 can be shielded more effectively. Several slits 45 are formed in the low-voltage circuit GND of the low-voltage circuit GND layer 44. The slits 45 are provided to avoid contact between the low-voltage circuit GND of the low-voltage circuit GND layer 44 and through-hole lands or via conductors formed on the multilayer substrate. Furthermore, if a conductor pattern is provided on the low-voltage circuit GND layer 44, the low-voltage circuit GND of the low-voltage circuit GND layer 44 must be shaped to avoid contact with the conductor pattern.

[0053] Furthermore, even when a high-voltage circuit GND is provided in place of the low-voltage circuit GND of the low-voltage circuit GND layer 44, it is desirable that the high-voltage circuit GND of the high-voltage circuit GND layer have a shape that seals the gap between the high-voltage circuit GND pattern 40 and the low-voltage circuit GND pattern 42.

[0054] The main circuit module 23 is formed by sealing the main circuit 22, on which switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL are mounted, with an insulating resin 21 such as epoxy. The main circuit 22 is provided with multiple signal transmission pins 25 for electrical connection to the drive circuits 24, 26, 28, 30, 32, 34 and the high-voltage circuit GND pattern 40 of the control board 38. The signal transmission pins 25 protrude from the insulating resin 21 toward the control board module 39. A heat sink 19 is provided on the side opposite to the side from which the signal transmission pins 25 protrude.

[0055] The signal transmission pins 25 can be connected to the conductor patterns or high-voltage circuit GND patterns 40 of the control board 38 by soldering or wire bonding. The control board module 39, like the main circuit module 23, is sealed with insulating resin 33.

[0056] The electric field noise generated from the switching elements 16UH, 16UL, 18VH, 18VL, 20WH, and 20WL of the main circuit 22 is radiated toward the control board 38, and can also propagate to the control board 38 side as a noise voltage via the signal transmission pin 25. If this noise voltage propagates, for example, to the high-voltage circuit GND pattern 40 of the control board 38, an oscillation in the ground potential occurs.

[0057] In this embodiment, the low-voltage circuit GND of the low-voltage circuit GND layer 44 is positioned opposite the high-voltage circuit GND pattern 40 via an insulating layer of the multilayer substrate, as shown in Figure 3. As a result, the high-voltage circuit GND pattern 40 and the low-voltage circuit GND of the low-voltage circuit GND layer 44 have stray capacitance, which allows them to function as a so-called bypass capacitor. Therefore, it is possible to reduce ground potential fluctuations caused by the propagation of noise voltage.

[0058] When a high-voltage circuit GND is provided in place of the low-voltage circuit GND of the low-voltage circuit GND layer 44, the high-voltage circuit GND of the high-voltage circuit GND layer is positioned to face the low-voltage circuit GND pattern 42 via an insulating layer of the multilayer substrate. This reduces ground potential oscillations due to noise voltage propagation, similar to the case of the low-voltage circuit GND of the low-voltage circuit GND layer 44.

[0059] The effectiveness of the inverter device 10 according to this embodiment was verified by a three-dimensional electromagnetic field simulation (ANSYS HFSS). Specifically, in the three-dimensional electromagnetic field simulation, a noise source of 0 dBm was applied to the main circuit 22. The maximum values ​​of the magnetic field and electric field were measured at the mounting positions of the six drive ICs on the control board 38, with and without the low-voltage circuit GND of the low-voltage circuit GND layer 44 (example).

[0060] Figure 6 shows the maximum measured magnetic field values ​​for the example and the comparative example. From the measurement results, it can be seen that the example achieved a magnetic field reduction effect of 15.2 dB compared to the comparative example. Figure 7 shows the maximum measured electric field values ​​for the example and the comparative example. From the measurement results, it can be seen that the example achieved an electric field reduction effect of 11.2 dB compared to the comparative example.

[0061] While preferred embodiments of this disclosure have been described above, this disclosure is not limited in any way to the embodiments described above and can be implemented in various modified forms without departing from the spirit of this disclosure.

[0062] For example, as shown in Figure 8, the low-voltage circuit GND layers 44A and 44B and the high-voltage circuit GND layer 46 may be provided on different layers of the multilayer substrate, respectively. This increases the area of ​​contact between the high-voltage circuit GND of the high-voltage circuit GND pattern 40 and the high-voltage circuit GND layer 46 and the low-voltage circuit GND pattern 42 and the low-voltage circuit GND layers 44A and 44B via the insulating layer. As a result, the stray capacitance increases, and therefore the oscillation of the ground potential can be reduced more effectively.

[0063] Figure 8 shows an example in which two low-voltage circuit GND layers 44A and 44B are provided, and one high-voltage circuit GND layer 46 is provided. In this way, when at least one of the low-voltage circuit GND layers 44A and 44B and the high-voltage circuit GND layer 46 is provided in multiple layers, the low-voltage circuit GND layers 44A and 44B and the high-voltage circuit GND layer 46 are provided alternately. This makes it possible to efficiently increase the facing area between the high-voltage circuit GND and the low-voltage circuit GND via the insulating layer.

[0064] Furthermore, in the above-described embodiment, an example was explained in which the drive circuits 24, 26, 28, 30, 32, 34 and the control circuit 36 ​​are mounted on the control board 38. However, the control circuit 36 ​​may be mounted on a different board instead of the control board 38. [Explanation of symbols]

[0065] 10: Inverter device, 11: High-potential power line, 12: High-voltage battery, 13: Low-potential power line, 14: Smoothing capacitor, 16, 18, 20: Output lines, 16UH, 16UL, 18VH, 18VL, 20WH, 20WL: Switching elements, 19: Heat sink, 21: Insulating resin, 22: Main circuit, 23: Main circuit module, 24, 26, 28, 30, 32, 34: Drive circuit, 25: Signal transmission pin, 35: Ground wire for high-voltage circuit, 36: Control circuit, 37: Ground wire for low-voltage circuit, 38: Control board, 39: Control board module, 40: High-voltage circuit GND pattern, 42: Low-voltage circuit GND pattern, 44, 44A, 44B: Low-voltage circuit GND layer, 45: Slit, 46: High-voltage circuit GND layer, 50: Electric motor

Claims

1. A main circuit module (23) including a main circuit (22) on which switching elements (16UH, 16UL, 18VH, 18VL, 20WH, 20WL) constituting the inverter are mounted, The control board module (39) includes a control board (38) on which drive circuits (24, 26, 28, 30, 32) that output drive signals for driving the switching elements are mounted, The control board is a multilayer board, The main circuit module and the control board module are integrated in the stacking direction of the multilayer substrate. On the same layer of the control board, a high-voltage circuit GND pattern (40) for the high-voltage circuit in the drive circuit and a low-voltage circuit GND pattern (42) for the low-voltage circuit in the drive circuit are provided separately. An inverter device in which, in a layer separate from the layer on which the high-voltage circuit GND pattern and the low-voltage circuit GND pattern are arranged, and located between the layer on which the high-voltage circuit GND pattern and the low-voltage circuit GND pattern are arranged and the main circuit module, at least one of a low-voltage circuit GND layer (44, 44A, 44B) having a low-voltage circuit GND that is conductive to the low-voltage circuit GND pattern and a high-voltage circuit GND layer (46) having a high-voltage circuit GND that is conductive to the high-voltage circuit GND pattern is provided.

2. The inverter device according to claim 1, wherein the low-voltage circuit GND of the low-voltage circuit GND layer and / or the high-voltage circuit GND of the high-voltage circuit GND layer have a shape that closes the gap between the high-voltage circuit GND pattern and the low-voltage circuit GND pattern in the stacking direction of the multilayer substrate.

3. The inverter device according to claim 1 or 2, wherein the low-voltage circuit GND of the low-voltage circuit GND layer is arranged to face the high-voltage circuit GND pattern via an insulating layer of the multilayer substrate, or the high-voltage circuit GND of the high-voltage circuit GND layer is arranged to face the low-voltage circuit GND pattern via an insulating layer of the multilayer substrate.

4. The inverter device according to claim 3, wherein the low-voltage circuit GND layer and the high-voltage circuit GND layer are provided on different layers of the multilayer substrate, respectively.

5. The inverter device according to claim 4, wherein, when at least one of the low-voltage circuit GND layer and the high-voltage circuit GND layer is provided in multiple layers, the low-voltage circuit GND layer and the high-voltage circuit GND layer are provided alternately.

6. The inverter device according to claim 1 or 2, wherein a control circuit (36) for controlling the drive circuit is mounted on the control board.

7. The high-voltage circuit GND pattern and the low-voltage circuit GND pattern are provided on the surface layer of the multilayer substrate on the side opposite to the side in which the main circuit module is integrated. The inverter device according to claim 6, wherein the drive IC incorporating the drive circuit and the control IC incorporating the control circuit are mounted on the surface layer of the multilayer substrate.

Images