Power conversion device

Abstract

Power conversion device (10) comprising: a printed circuit board (300) with a first ground (310) which forms a ground of a first circuit, and a second ground (320) which is designed to be electrically separated from the first ground (310); a second circuit in which a joining section is formed; a metal base plate (200) provided between the second circuit and the printed circuit board (300) and provided with an opening section (210) corresponding to the joining section; and a housing (100) that accommodates the printed circuit board (300), the second circuit and the metal base plate (200) and is electrically connected to the second grounding (320) of the printed circuit board (300) and the metal base plate (200), wherein the joining section (191 to 196) of the second circuit is arranged according to the second grounding (320) through the opening section (210) of the metal base plate (200).

Description

Technical field

[0001] The present invention relates to a power conversion device. State of the art

[0002] A power conversion device is known in which a storage chamber of a high-voltage main circuit with a switching element and a storage chamber of a control circuit that generates a control signal for controlling the switching element are divided in two by a metal base plate in a housing.

[0003] PTL 1 describes a power converter in which, to reduce noise, the interior of a metal housing is divided into two compartments by a metal base plate. A control circuit is mounted in one of the compartments, while a driver circuit and a power module are mounted in the other. PTL 2 further discloses a power conversion device. It uses two parallel, separately cooled units: one for the power semiconductor modules and another for the capacitor and busbar. The units are arranged on a housing base, with openings in the base providing access to connect the DC terminals between the units. PTL 3 describes a power conversion device with a capacitor and power module arranged side-by-side in a metal housing. To reduce line noise, a noise shield is positioned between the circuit board and the capacitor module.The shielding plate extends laterally beyond the ground plane of the printed circuit board, and its nearest grounding point is closer to the power module than the edge of the ground plane. PTL 4 describes a power converter for noise suppression. A power transistor is connected to the chassis via a conductive plate and an insulating layer, creating parasitic capacitance. A noise suppression capacitor on the control board connects the transistor's collector to the grounded chassis to divert the noise along a short path and prevent its propagation. Finally, PTL 5 describes an inverter in which a conductive shielding plate is placed between the power module and the control board. This shielding plate is not connected to the chassis but directly to the DC power supply line and is insulated from the chassis. This arrangement is intended to prevent noise from the power module or chassis from interfering with the control circuitry. List of prior art patent literature PTL 1: JP 2010-183763 A PTL 2: US 2014 / 160 823 A1 PTL 3: DE 11 2015 002 670 T5 PTL 4: JP 2017 - 017 881 A PTL 5: JP 2006 - 050 685 A Summary of the invention: Technical problem

[0004] When the power conversion device is miniaturized, the interior space is narrowed, and it is necessary to create an opening section in a metal base plate to bypass a joining section of the circuit; however, there is a problem that noise propagating through this opening section is affected. Solution to the problem

[0005] The subject of the present invention is a power conversion device with the features of claim 1. Advantageous further developments are defined in the dependent claims. Advantageous effects of the invention

[0006] According to the present invention, the influence of noise propagating through the opening section of the metal base plate can be suppressed.

[0007] Other problems, configurations and effects than those described above are clarified by the description of the present embodiments. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a circuit configuration view that shows a configuration of a power conversion device and a configuration of a motor drive system to which the power conversion device is applied. [ Fig. 2] Fig. Figure 2 is a perspective view in an expanded arrangement, which represents an example of a structure of a power conversion device according to a first embodiment. [ Fig. 3] Fig. Figure 3 is a cross-sectional projection view showing an example of a structure of the power conversion device according to the first embodiment. [ Fig. 4] Fig. Figure 4 is a top view showing an example of the circumference of an opening section of a metal base plate of the power conversion device according to the first embodiment. [ Fig. 5] Fig. Figure 5 is a perspective view in an expanded arrangement, which represents an example of a structure of a power conversion device according to a second embodiment. [ Fig. 6] Fig. Figure 6 is a top view showing an example of the circumference of an opening section of a metal base plate of the power conversion device according to the second embodiment. [ Fig. 7] Fig. Figure 7 is a perspective view in an expanded arrangement, which represents an example of a structure of a power conversion device according to a third embodiment. [ Fig. 8] Fig. Figure 8 is a cross-sectional projection view showing an example of a structure of the power conversion device according to the third embodiment. [ Fig. 9] Fig. Figure 9 is a top view showing an example of the circumference of an opening section of a metal base plate of the power conversion device according to the third embodiment. Description of embodiments

[0008] The following describes embodiments of the present invention with reference to the drawings. Each embodiment serves as an example to illustrate the present invention and is omitted or simplified as appropriate for clarity. The present invention can also be implemented in various other forms. Unless otherwise specified, each component can be single or multiple.

[0009] For the purpose of facilitating understanding of the invention, the position, size, shape, area, and the like of each component shown in the drawings do not necessarily represent the actual position, size, shape, area, and the like. Therefore, the present invention is not necessarily limited to the position, size, shape, area, and the like disclosed in the drawings. [First embodiment]

[0010] The first embodiment of the present invention is described below with reference to Fig. 1 to 4 described.

[0011] Fig. Figure 1 is a circuit configuration view showing the configuration of a power conversion device 10 according to the present embodiment and the configuration of a motor drive system to which the power conversion device 10 is applied. The in Fig. The motor drive system shown in Figure 1 is an example in which a direct current voltage is converted into an alternating current voltage to drive a motor of an electric vehicle, a hybrid vehicle or the like.

[0012] In Fig. The power conversion device 10 is housed in a metal casing 100. Low-voltage DC power, e.g., 9 to 14 V, for driving a motor control circuit 170 of the power conversion device 10 is supplied by a low-voltage power supply 20 via a low-voltage connection element 101. High-voltage DC power, e.g., 320 to 900 V, is supplied by a high-voltage power supply 30 to the power conversion device 10 via a high-voltage connection element 102. Various circuit blocks and circuit elements are housed in the casing 100 of this power conversion device 10, and only those required for the description are shown among these circuit blocks and circuit elements. Fig. 1 shown. Fig. 1 represents a motor 40 which is driven by an alternating voltage generated by the power conversion device 10.

[0013] A high-voltage power supply 30 is generally a battery or one obtained by converting an AC power supply to a DC voltage using a converter. For example, a drive inverter of a hybrid vehicle uses a high-voltage battery of several hundred volts as its high-voltage power supply 30. Since a medical device such as an X-ray diagnostic device uses a commercial AC power supply, it is converted to a DC high-voltage power supply 30 using a rectifier circuit or a converter.

[0014] Although not particularly limited, the motor 40 is configured as a three-phase electric motor. This motor 40 comprises a rotor (not shown) and a stator (not shown) and has three coils arranged in the stator. The power conversion device 10 generates a three-phase alternating voltage and supplies the alternating voltage to the three coils to produce a magnetic field according to the three-phase alternating voltage and to rotate the rotor.

[0015] Next, the configuration of the power conversion device 10 is described. The power conversion device 10 comprises, within the housing 100, a low-voltage connection element 101, a high-voltage connection element 102, a motor wiring harness connection element 103, an anode bus 111, a cathode bus 112, an anode Y-capacitor 121, a cathode Y-capacitor 122, an anode-cathode X-capacitor 130, switching elements 141 to 143, AC bus bars 151 to 153, current sensors 161 to 163, a motor control circuit 170, and a gate driver circuit 180.

[0016] As described above, the high-voltage direct current power supplied by the high-voltage power supply 30 is fed to the switching elements 141 to 143 via the anode current rail 111 and the cathode current rail 112. Since the switching elements 141 to 143 generate a high-frequency switching current and a high-frequency switching voltage at the time of switching, the X-capacitor 130 is generally used to smooth these. Although in Fig. Not shown in Figure 1, several capacitors with a capacitance of approximately a few tens of microfarads are connected in parallel. Here, an anode terminal of the X-capacitor 130 is connected to the anode rail 111, and a cathode terminal of the X-capacitor 130 is connected to the cathode rail 112. Although not particularly limited, these anode rail 111 and cathode rail 112 are copper plates. The Y-capacitor 121 is connected between the anode rail 111 and the chassis 100, and the Y-capacitor 122 is connected between the cathode rail 112 and the chassis 100, thus reducing common-mode noise superimposed on the anode rail 111 and the cathode rail 112.

[0017] The switching elements 141 to 143 are generally semiconductor devices such as IGBTs, MOSFETs, and SiCs. A desired voltage and current are generated by switching these semiconductor devices (switching between on and off). The switching outputs of the switching elements 141 to 143 are connected from the AC busbars 151 to 153 to the motor 40 via the motor wiring harness connector 103. The current sensors 161 to 163 are attached to the AC busbars 151 to 153, and a current value flowing through all AC busbars 151 to 153 is supplied to the motor control circuit 170 as an AC monitoring signal 182.

[0018] Upon receiving the AC monitoring signal 182, the motor control circuit 170 generates a PWM signal and feeds the PWM signal to the gate driver circuit 180. The gate driver circuit 180 inputs a gate control signal 181 into the gate terminals of the switching elements 141 to 143 in order to actuate the switching elements 141 to 143.

[0019] In the power conversion device 10 configured in this way, the switching elements 141 to 143 are switched by the gate control signal 181 from the gate driver circuit 180, and the anode voltage and the cathode voltage are periodically output from the AC rails 151 to 153, so that the switching elements 141 to 143 are periodically switched on / off. Therefore, the voltage / current in the anode current rail 111 and the cathode current rail 112 changes, and noise is generated.

[0020] Fig. Figures 2 to 4 are views that illustrate examples of the structure of the power conversion device 10.

[0021] Fig. Figure 2 is a perspective view in an unfolded arrangement, illustrating an example of the structure of the power conversion device 10 according to the present embodiment. In the figure, when the power conversion device 10 is unfolded, the Y capacitors 121 and 122, the X capacitor 130, and the switching elements 141 to 143 are housed in a lower section of a box-shaped enclosure 100, from which a cover has been removed. The anode bus 111 and the cathode bus 112 are stacked apart from each other and are connected to terminals of the Y capacitors 121 and 122 and the X capacitor 130. The anode current rail 111 and the cathode current rail 112, which are high-voltage sections, are connected to the input terminals of the switching elements 141 to 143, which are high-voltage sections, by joining screws 191 to 196.The joining screws 191 to 196 are joining sections for electrically connecting the anode busbar 111 and the cathode busbar 112 to the switching elements 141 to 143. Fig. 2. Due to the properties of the view in the disassembled arrangement, not all assembly screws can be shown, but the assembly is shown at six parts at six connecting parts of the anode current rail 111 and the cathode current rail 112 with the switching elements 141 to 143 in Fig. 1. A circuit with the anode current rail 111, the cathode current rail 112, the assembly screws (assembly sections) 191 to 196 and the switching elements 141 to 143 is referred to as the second circuit.

[0022] The metal base plate 200 is arranged above the second circuit, which is a high-voltage section, to prevent the high-frequency noise generated by the switching operation of the switching elements 141 to 143, which are also high-voltage sections, from propagating to the motor control circuit 170, which is a low-voltage section, in the power conversion device 10. A printed circuit board 300, on which the motor control circuit 170 and the like are arranged, is arranged above the metal base plate 200.

[0023] The motor control circuit 170 and the gate driver circuit 180, which are in Fig. As shown in Figure 1, a first PCB ground pattern 310 and a second PCB ground pattern 320 are arranged on the printed circuit board 300. The first PCB ground pattern 310 and the second PCB ground pattern 320 are not electrically connected to each other on the printed circuit board 300. Here, the motor control circuit 170 is a circuit that operates with a low-voltage source supplied by the low-voltage power supply 20 and uses the first PCB ground pattern 310 as a reference ground. The motor control circuit 170 on the printed circuit board 300 is referred to as the first circuit.

[0024] On the other hand, the gate driver circuit 180 is a circuit connected to the switching elements 141 to 143, which are high-voltage sections, and belongs to the high-voltage section; and therefore the first PCB GND pattern 310 is not used as a reference.

[0025] The metal base plate 200 has an opening section 210 to prevent contact with the assembly screws 191 to 196, and noise propagates to the low-voltage section via this opening section 210. Four corners of this opening section 210 are provided with hubs (connection hubs 231 to 234 of the second circuit board GND pattern) for electrical connection to the circuit board 300, which is located further above the metal base plate 200, and are electrically connected to the second circuit board GND pattern 320 of the circuit board 300.This electrical connection method is assumed, for example, as a method to bring the connection hubs 231 to 234 of the second circuit board GND pattern directly into contact without applying a protective film to the second circuit board GND pattern 320, as a method for inserting a seal, as a method for bringing into contact using a spring, as a screwing method and the like, but the method is not limited in the present embodiment.

[0026] The metal base plate 200 includes circuit board mounting hubs 221 to 226 for mounting the circuit board 300 and the metal base plate 200 and the first circuit board GND pattern 310 of the circuit board 300 are connected by the circuit board mounting hubs 221, 222, 225 and 226.

[0027] Fig. Figure 3 is a cross-sectional projection view illustrating an example of the structure of the power conversion device 10 according to the present embodiment. The figure is a cross-sectional projection view of a Fig. The arrow 500 shown in Figure 2 is considered, which is not a view of a specific straight plane, but a projection of a depth direction to illustrate the structure of the power conversion device 10. The figure shows the low-voltage connecting element 101, the high-voltage connecting element 102, the motor wiring harness connecting element 103, the anode current rail 111, the cathode current rail 112, the Y capacitors 121 and 122, the switching elements 141 to 143, the gate drive signal 181, the assembly screws 191 to 196, the metal base plate 200, the opening section 210, the circuit board mounting hubs 221 to 226, the connecting hubs 231 to 234 of the second circuit board GND pattern, the circuit board 300, the first circuit board GND pattern 310 and the second circuit board GND pattern 320 as already shown in Fig. 1 and Fig. 2 described and their explanations are omitted. A mounting area 171 of the first circuit on the printed circuit board 300 in Fig. 3 is an area in which the low-voltage circuit is mounted centered on the motor control circuit 170 as described above, and a mounting area 183 of the second circuit is an area in which the high-voltage circuit is mounted centered on the circuit with the anode current rail 111, the cathode current rail 112, the assembly screws (assembly sections) 191 to 196 and the switching elements 141 to 143 as described above.

[0028] The metal base plate 200 is positioned between the second circuit and the printed circuit board 300, and the opening section 210 is arranged according to the assembly screws (assembly sections) 191 to 196. The housing 100 contains the printed circuit board 300, the second circuit, and the metal base plate 200 and is electrically connected to the second circuit board ground pattern 320 of the printed circuit board 300 and the metal base plate 200. The assembly section of the second circuit is positioned over the opening section 210 of the metal base plate 200 according to the second circuit board ground pattern 320. It should be noted that "positioned accordingly" means that the assembly section of the second circuit and the second circuit board ground pattern 320 are in a corresponding positional relationship, and the opening section 210 of the metal base plate 200 is positioned between them.It should be noted that “arranged accordingly” includes a configuration in which the joining section of the second circuit and the second circuit board GND pattern 320 are arranged to face each other, and the opening section 210 of the metal base plate 200 is positioned between them. It should also be noted that “arranged accordingly” includes a configuration in which the joining section of the second circuit, an area in which the metal base plate 200 is not present (e.g., the opening section 210), and the second circuit board GND pattern 320 are arranged to overlap, at least partially, when viewed from a direction perpendicular to an implementation surface of the circuit board 300. A metal cover 400 forms part of the housing 100 in the power conversion device 10.

[0029] Here, the structure of the perimeter of the opening section 210 of the metal base plate 200 is described with reference to Fig. 3 described in more detail. One of the performance indices for the power conversion device 10 is the housing size, and the constraints in the height direction were also strict. In such a case, the metal base plate 200 must be arranged at a minimum distance required for insulation from the high-voltage section, which is the second circuit with the anode current rail 111, the cathode current rail 112, and the switching elements 141 to 143. In such a case, the opening section 210 is located in the mounting area 183 of the second circuit, as shown in Fig. Figure 3 shows the provision in the metal base plate 200 to ensure the insulation distance from the metal base plate 200, while avoiding the height of the screw heads of the joining screws 191 to 196, which join the anode bus 111 and the cathode bus 112 with the switching elements 141 to 143, in other words, because volume is required for the joining section. The connecting hubs 231 to 234 of the second circuit board GND pattern can be located at one end of the opening section 210 or can be located, for example, about 10 mm away from the end of the opening section 210.

[0030] Fig. Figure 4 is a top view showing an example of the extent of the opening section 210 of the metal base plate 200 of the power conversion device 10 according to the present embodiment. The figure shows the anode bus 111, the cathode bus 112, the Y capacitors 121 and 122, the switching elements 141 to 143, the assembly screws 191 to 196, the opening section 210, the connecting hubs 231 to 234 of the second board GND pattern, and the second board GND pattern 320 as shown in Figure 4. Fig. Items 1 to 3 are described and their explanation is omitted.

[0031] The positional relationship under the opening section 210 of the metal base plate 200, the second circuit board GND 320 of the circuit board 300 and the connecting hubs 231 to 234 of the second circuit board GND pattern is described with reference to Fig. 4 described in more detail. First, the opening section 210 of the metal base plate 200 serves to maintain the insulation distance from the joining screws 191 to 196, and the size of the opening section 210 is determined according to the insulation distance. The connecting hubs 231 to 234 of the second circuit board GND pattern are arranged such that they are in contact with the outside of the four corners of the opening section 210 of the metal base plate 200, and the second circuit board GND pattern 320 is arranged in the same position and with the same size as those of a rectangle formed by the connecting hubs 231 to 234 of the second circuit board GND pattern. The second circuit board GND pattern 320 is connected to the metal base plate 200 by a connecting element such as a screw or a screw. B. the connecting hubs 231 to 234 of the second circuit board GND pattern are connected and the metal base plate 200 is connected to the housing 100.

[0032] In the power conversion device 10 according to the present embodiment, the second circuit board ground pattern 320 is provided such that it is wider than the size of the opening section 210 with respect to the opening section 210 provided in the metal base plate 200, thereby forming the second circuit board ground pattern 320, which is configured in a shape to cover the opening section 210. With this structure, it is possible to create the power conversion device 10, which is capable of suppressing an increase in the amount of noise that propagates from the high-voltage section to the low-voltage section, such as...to the first circuit board GND pattern 310 and to the mounting area 171 of the first circuit, even if the opening section 210, which avoids the joining section, exists in the metal base plate 200 to maintain the isolation distance from the joining section, which connects the anode current rail 111 and the cathode current rail 112 to the switching elements 141 to 143, to the metal base plate 200.

[0033] With the power conversion device 10 according to the present embodiment, it is possible to create, at low cost, a power conversion device that is able to minimize an additional countermeasure element and suppress an increase in the amount of noise propagating from the high-voltage section to the low-voltage section, such as to the first board-mounted GND pattern 310 and the mounting area 171 of the first circuit, using the second board-mounted GND pattern 320, which is part of the board-mounted pattern, as a shielding plate for electromagnetic noise. [Second embodiment]

[0034] The second embodiment of the present invention is described below with reference to Fig. 5 and Fig. 6 described. It should be noted that the circuit configuration view, which shows the configuration of a power conversion device 10 and the configuration of a motor drive system to which the power conversion device 10 is applied, is described in Fig. The embodiment shown in Figure 1 is the same in the present embodiment. Fig. 5 and Fig. 6 are the same parts as those in Fig. Reference symbols 1 to 4 are given and their explanation is omitted.

[0035] Fig. Figure 5 is a perspective view in an expanded arrangement, illustrating an example of the structure of the power conversion device 10 according to the present embodiment. The difference in the figure compared to the power conversion device 10 according to the first embodiment, which is shown in Fig. 2 is shown in that a connecting wall 235 of the second board GND pattern is formed instead of the connecting hubs 231 to 234 of the second board GND pattern.

[0036] Similar to the first embodiment, the metal base plate 200 has the opening section 210 to prevent contact with the assembly screws 191 to 196, i.e., assembly sections, and noise propagates to the low-voltage section via this opening section 210. A wall (connecting wall 235 of the second circuit board GND pattern) is provided around the perimeter of the opening section 210 for electrical connection to the circuit board 300, which is arranged above the metal base plate 200, and is electrically connected to the second circuit board GND pattern 320 of the circuit board 300.This electrical connection method is assumed, for example, to be a method for bringing the connecting wall 235 of the second circuit board GND pattern directly into contact with the second circuit board GND pattern 320 without applying a protective film, a method for inserting a seal, a method for bringing into contact using a spring, a screwing method, and the like, but the method is not limited in the present embodiment.

[0037] Fig. Figure 6 is a top view showing an example of the circumference of the opening section 210 of the metal base plate 200 of the power conversion device 10 according to the present embodiment. The difference in the figure compared to the power conversion device 10 according to the first embodiment, which is shown in Fig. 4 is shown in that a connecting wall 235 of the second board GND pattern is formed instead of the connecting hubs 231 to 234 of the second board GND pattern.

[0038] The positional relationship under the opening section 210 of the metal base plate 200, the second circuit board GND 320 of the circuit board 300 and the connecting wall 235 of the second circuit board GND pattern is described with reference to Fig. 6 is described in more detail. First, the opening section 210 of the metal base plate 200 corresponds to the joining screws 191 to 196 and serves to maintain the insulation distance from the joining screws 191 to 196, and the size of the opening section 210 is determined according to the insulation section. The connecting wall 235 of the second circuit board GND pattern is arranged such that it is in contact with the outside of the four corners of the opening section 210 of the metal base plate 200, and the second circuit board GND pattern 320 is arranged in the same position and with the same size as that of a rectangle formed by the connecting wall 235 of the second circuit board GND pattern. The second circuit board GND pattern 320 is connected to the metal base plate 200 via the connecting wall 235 of the second circuit board GND pattern and the metal base plate 200 is connected to the housing 100.

[0039] In the power conversion device 10 according to the present embodiment, the second circuit board ground pattern 320 is provided such that it is wider than the size of the opening section 210 with respect to the opening section 210 provided in the metal base plate 200, thereby forming the second circuit board ground pattern 320 which is configured in a shape to cover the opening section 210 without a gap. With this structure, it is possible to create the power conversion device 10 which is capable of suppressing an increase in the amount of noise that propagates from the high-voltage section to the low-voltage section, such as...to the first circuit board GND pattern 310 and to the mounting area 171 of the first circuit, even if the opening section 210, which avoids the joining section, exists in the metal base plate 200 to maintain the isolation distance from the joining section, which connects the anode current rail 111 and the cathode current rail 112 to the switching elements 141 to 143, to the metal base plate 200. [Third embodiment]

[0040] The third embodiment of the present invention is described below with reference to Fig. 7 to 9 described. It should be noted that the circuit configuration view, which shows the configuration of a power conversion device 10 and the configuration of a motor drive system to which the power conversion device 10 is applied, is described in Fig. The embodiment shown in Figure 1 is the same in the present embodiment. Fig. 7 to 9 are the same parts as those in Fig. Reference symbols 1 to 6 are given the same and their explanation is omitted.

[0041] Fig. Figure 7 is a perspective view in an expanded arrangement, illustrating an example of the structure of the power conversion device 10 according to the third embodiment of the present invention. The difference in the figure compared to the power conversion device 10 according to the second embodiment, which is shown in Fig. Figure 5 shows a form in which the metal base plate 200 is in a position that covers at least the anode current rail 111 and the cathode current rail 112, and is not located above the switching elements 141 to 143. This form is assumed to be, for example, a case in which the shape of the switching elements 141 to 143 interferes with the metal base plate 200, a case in which the number of signal connections between the switching elements 141 to 143 and the circuit board 300 is large, or the like.

[0042] Similar to the first and second embodiments, the metal base plate 200 has the opening section 210 to prevent contact with the assembly screws 191 to 196, i.e., assembly sections, and noise propagates to the low-voltage section via this opening section 210. A wall (connecting wall 235 of the second circuit board GND pattern) for electrical connection to the circuit board 300, which is arranged above the metal base plate 200, is arranged in a U-shape around the perimeter of the opening section 210 and is electrically connected to the second circuit board GND pattern 320 of the circuit board 300.This electrical connection method is assumed, for example, to be a method for bringing the connecting wall 235 of the circuit board GND pattern directly into contact with the second circuit board GND pattern 320 without applying a protective film, a method for inserting a seal, a method for bringing into contact using a spring, a screwing method, and the like, but the method is not limited in the present embodiment.

[0043] Fig. Figure 8 is a cross-sectional projection view illustrating an example of the structure of the power conversion device 10 according to the present embodiment. The figure is a cross-sectional projection view of a Fig. The arrow 500 shown in Figure 7 is considered, which is not a view of a specific straight plane, but a projection of a depth direction to illustrate the structure of the power conversion device 10. The figure shows the difference to the power conversion device 10 according to the second embodiment, which is shown in Figure 7. Fig. 5 is shown, as with reference to Fig. 7 described a structure in which the metal base plate 200 is cut to the left end of the switching elements 141 to 143, and a U-shaped connecting wall 236 of the second circuit board GND pattern surrounds the opening section 210 in a U-shape.

[0044] Fig. Figure 9 is a top view showing an example of the circumference of the opening section 210 of the metal base plate 200 of the power conversion device 10 according to the present embodiment. The difference in the figure compared to the power conversion device 10 according to the second embodiment, which is shown in Fig. 6 is shown in that the U-shaped connecting wall 236 of the second circuit board GND pattern is formed instead of the connecting wall 235 of the second circuit board GND pattern by reducing the size of the metal base plate 200.

[0045] The positional relationship under the opening section 210 of the metal base plate 200, the second circuit board GND pattern 320 of the circuit board 300 and the connecting wall 236 of the second circuit board GND pattern is described with reference to Fig.9 is described in more detail. First, the opening section 210 of the metal base plate 200 corresponds to the joining screws 191 to 196 and serves to maintain the insulation distance from the joining screws 191 to 196, and the size of the opening section 210 is determined according to the insulation distance. The U-shaped connecting wall 236 of the second circuit board GND pattern is arranged such that it is in contact with the outside of the four corners of the opening section 210 of the metal base plate 200, and there is no wall on the side facing the switching elements 141 to 143. The second circuit board GND pattern 320 has an area that is sufficiently larger than that of a rectangle formed by the connecting wall 236 of the second circuit board GND pattern and the opening section 210.The second circuit board GND pattern 320 is connected to the metal base plate 200 via the connecting wall 236 of the second circuit board GND pattern and the metal base plate 200 is connected to the housing 100.

[0046] In the power conversion device 10 according to the present embodiment, the second circuit board ground pattern 320 is provided such that it is wide with respect to the opening section 210 provided in the metal base plate 200, thereby forming the second circuit board ground pattern 320 which is configured in a shape to cover the opening section 210. With this structure, it is possible to create the power conversion device 10 which is capable of suppressing an increase in the amount of noise that propagates from the high-voltage section to the low-voltage section, such as...to the first circuit board GND pattern 310 and to the mounting area 171 of the first circuit, even if the opening section 210, which avoids the joining section, exists in the metal base plate 200 to maintain the isolation distance from the joining section, which connects the anode current rail 111 and the cathode current rail 112 to the switching elements 141 to 143, to the metal base plate 200.

[0047] In the power conversion device 10 according to the present embodiment, it is possible to create the power conversion device 10 which is able to suppress an increase in the amount of noise that propagates from the high-voltage section to the low-voltage section, such as to the first circuit board GND pattern 310 and the mounting area 171 of the first circuit, even if the area of ​​the metal base plate 200 is reduced.

[0048] According to the embodiments described above, the following operational effects can be obtained.

[0049] (1) The power conversion device 10 comprises: the printed circuit board 300 with the first circuit board ground pattern 310 (the first ground) 310, which forms the ground of the first circuit (the motor control circuit 170), and the second circuit board ground pattern (the second ground) 320, which is configured to be electrically isolated from the first ground 310; the second circuit (the anode current rail 111, the cathode current rail 112 and the switching elements 141 to 143), in which the assembly screws (assembly sections) 191 to 196 are formed; the metal base plate 200, which is provided between the second circuit and the printed circuit board 300 and is provided with the opening section 210, which corresponds to the assembly sections 191 to 196;and the housing 100, which accommodates the printed circuit board 300, the second circuit and the metal base plate 200 and is electrically connected to the second ground 320 of the printed circuit board 300 and the metal base plate 200, wherein the joining sections 191 to 196 of the second circuit are arranged across the opening section 210 of the metal base plate 200 in accordance with the second ground 320. This can suppress the influence of noise propagating through the opening section 210 of the metal base plate 200.

[0050] The present invention is not limited to the embodiments described above, and other forms conceivable within the scope of protection of the technical idea of ​​the present invention are also included within the scope of protection of the present invention, as long as the features of the present invention are not impaired. The embodiments described above have been explained in detail for the sake of clarity in understanding the present invention, and the present invention is not necessarily limited to those with all the configurations described. It is possible to replace part of the configuration of a particular embodiment with part of the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of a particular embodiment.The configuration of another embodiment can be added to, removed from, or replaced with a part of the configuration of any embodiment.

[0051] The disclosure of the following priority application is incorporated herein by reference.

[0052] Japanese patent application 2019-125886 (filed on July 5, 2019) Reference symbol list 10 Power conversion device 20 Low-voltage power supply 30 High-voltage power supply 40 engine 100 cases 101 Low-voltage connection element 102 High-voltage connecting element 103 Engine wiring harness connector 111 Anode busbar 112 Cathode busbar 121, 122 Y-capacitor 130 X-capacitor 141, 142, 143 Switching element 151, 152, 153 AC busbar 161, 162, 163 Current sensor 170 Engine control unit 171 Assembly area of ​​the first circuit 180 gate driver circuit 181 Gate control signal 182 AC monitoring signal 183 Mounting area of ​​the second circuit 191 to 196 Joining screw 200 metal base plate 210 Opening section 221 to 226 Circuit board mounting hub 231 to 234 Connection hub of the second circuit board GND pattern 235 Connecting wall of the second circuit board GND pattern 236 U-shaped connecting wall of the second circuit board GND pattern 300 printed circuit boards 310 first circuit board GND sample 320 second circuit board GND pattern 400 metal lids

Claims

[1] Power conversion device (10) comprising: a printed circuit board (300) with a first ground (310) which forms a ground of a first circuit, and a second ground (320) which is designed to be electrically separated from the first ground (310); a second circuit in which a joining section is formed; a metal base plate (200) provided between the second circuit and the printed circuit board (300) and provided with an opening section (210) corresponding to the joining section; and a housing (100) that accommodates the printed circuit board (300), the second circuit and the metal base plate (200) and is electrically connected to the second grounding (320) of the printed circuit board (300) and the metal base plate (200), wherein the joining section (191 to 196) of the second circuit is arranged according to the second grounding (320) through the opening section (210) of the metal base plate (200). [2] Power conversion device (10) according to claim 1, wherein the assembly section (191 to 196) of the second circuit is arranged such that it faces the second grounding (320) through the opening section (210) of the metal base plate (200). [3] Power conversion device (10) according to claim 1, wherein the second circuit, an area in which the metal base plate (200) is not present, and the second grounding (320) are configured such that they overlap at least partially when viewed from a direction perpendicular to an implementation surface of the printed circuit board (300). [4] Power conversion device (10) according to claim 1, wherein at least a part of a circumference of the opening section (210) of the metal base plate (200) is connected to the second grounding (320) of the circuit board (300) via a connecting element (231 to 234). [5] Power conversion device (10) according to claim 4, wherein the circumference of the opening section (210) of the metal base plate (200) is connected to the second grounding (320) of the circuit board (300) via the wall-shaped connecting element (235, 236). [6] Power conversion device (10) according to claim 4 or 5, wherein the second grounding (320) of the circuit board (300) is connected to the housing (100) through the metal base plate (200) via the connecting element (231 to 236). [7] Power conversion device (10) according to claim 1, wherein the joining section is a joining part that connects an anode current rail (111) and a cathode current rail (112) to a switching element. [8] Power conversion device (10) according to claim 7, wherein the first circuit includes a motor control circuit (170) which has a low voltage, and The second circuit comprises an anode current rail (111), a cathode current rail (112) and a switching element, which have a high voltage. [9] Power conversion device (10) according to claim 7 or 8, wherein the metal base plate (200) is arranged in a position that covers at least the anode busbar (111) and the cathode busbar (112).

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