Power conversion device

Abstract

The power conversion device of the present invention includes: a circuit substrate, which has a first ground constituting a ground of a first circuit and a second ground formed electrically separated from the first ground; a second circuit, which is formed with a joint; a metal base plate, which is arranged between the second circuit and the circuit substrate and has an opening corresponding to the joint; and a shell, which accommodates the circuit substrate, the second circuit and the metal base plate, is electrically connected to the second ground of the circuit substrate and the metal base plate, and the joint of the second circuit is configured corresponding to the second ground via the opening of the metal base plate.

Description

Technical Field

[0001] The invention relates to a power conversion device. Background Art

[0002] A power conversion device is known in which a housing chamber for a high voltage main circuit including a switching element and a housing chamber for a control circuit generating a control signal for driving the switching element are divided into two parts within a casing by a metal bottom plate.

[0003] Patent Document 1 describes a power conversion device in which the internal space of a metal casing is divided into two spaces by a metal bottom plate in order to reduce noise, a control circuit is mounted in one space, and a drive circuit and a power module are mounted in the other space.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-183763 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] When the power conversion device is miniaturized, the internal space becomes narrower, and it is necessary to provide an opening in the metal base plate to avoid the junction of the circuit. However, there is a problem that the device is affected by noise propagating through the opening.

[0009] Technical solutions adopted to solve technical problems

[0010] The power conversion device involved in the embodiment of the present invention preferably includes: a circuit substrate, which has a first ground constituting a ground of a first circuit, and a second ground formed by being electrically separated from the first ground; a second circuit, which has a joint; a metal base plate, which is arranged between the second circuit and the circuit substrate and has an opening corresponding to the joint; and a shell, which accommodates the circuit substrate, the second circuit and the metal base plate, and is electrically connected to the second ground of the circuit substrate and the metal base plate, and the joint of the second circuit is configured corresponding to the second ground via the opening of the metal base plate.

[0011] Effects of the Invention

[0012] According to the present invention, the influence of noise propagating through the opening of the metal base plate can be suppressed.

[0013] Problems, structures, and effects other than those described above will become more apparent through the following description of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a circuit configuration diagram showing the configuration of a power conversion device and the configuration of a motor drive system to which the power conversion device is applied.

[0015] Figure 2 It is an exploded perspective view showing an example of the structure of the power conversion device according to the first embodiment.

[0016] Figure 3 It is a cross-sectional projection diagram showing an example of the structure of the power conversion device according to the first embodiment.

[0017] Figure 4 It is a plan view showing an example of the periphery of the opening portion of the metal base plate of the power conversion device according to the first embodiment.

[0018] Figure 5 It is an exploded perspective view showing an example of the structure of the power conversion device according to the second embodiment.

[0019] Figure 6 It is a plan view showing an example of the periphery of the opening portion of the metal bottom plate of the power conversion device according to the second embodiment.

[0020] Figure 7 It is an exploded perspective view showing an example of the structure of a power conversion device according to the third embodiment.

[0021] Figure 8 It is a cross-sectional projection diagram showing an example of the structure of the power conversion device according to the third embodiment.

[0022] Fig. 9 It is a plan view showing an example of the periphery of the opening portion of the metal bottom plate of the power conversion device according to the third embodiment. DETAILED DESCRIPTION

[0023] Below, with reference to the accompanying drawings, the embodiments of the present invention are described. The embodiments are examples for illustrating the present invention. In order to make the description clear, they are appropriately omitted and simplified. The present invention can also be implemented in various other ways. Unless otherwise specified, each structural element can be single or multiple.

[0024] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each structural element shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0025] [First embodiment]

[0026] Below, refer to Figures 1 to 4 A first embodiment of the present invention will be described.

[0027] Figure 1 1 is a circuit configuration diagram showing the configuration of the 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. Figure 1 The motor drive system shown is shown as an example of converting a DC voltage into an AC voltage to drive a motor of an electric vehicle, a hybrid vehicle, or the like.

[0028] Figure 1 In the embodiment, the power conversion device 10 is housed in a metal housing 100. In addition, a low voltage DC power, for example, 9 to 14 V, for driving the motor control circuit 170 of the power conversion device 10 is supplied via a low voltage connector 101 from a low voltage power supply 20. In addition, a high voltage DC power, for example, 320 to 900 V, is supplied to the power conversion device 10 from a high voltage power supply 30 via a high voltage connector 102. Various circuit modules and components are stored in the housing 100 of the power conversion device 10. Figure 1 Only those components necessary for the description of these circuit modules and elements are depicted. Figure 1 2 shows a motor 40 driven by the AC voltage generated by the power conversion device 10 .

[0029] The high voltage power supply 30 generally uses a battery or a voltage obtained by converting an AC power supply into a DC voltage through a converter. For example, a high voltage battery of several hundred volts is used as the high voltage power supply 30 in a driving inverter of a hybrid vehicle. In addition, for example, medical devices such as X-ray diagnostic devices use commercial AC power, and therefore use a rectifier circuit or a converter to convert the high voltage power supply 30 into a DC power supply.

[0030] The motor 40 is not particularly limited and is composed of a three-phase motor. The motor 40 includes a rotor (not shown) and a stator (not shown), and three coils are arranged on the stator. The power conversion device 10 forms a three-phase AC voltage and supplies it to the three coils, thereby generating a magnetic field corresponding to the three-phase AC voltage to rotate the rotor.

[0031] Next, the structure of the power conversion device 10 is described. The power conversion device 10 includes a low voltage connector 101, a high voltage connector 102, a motor harness connector 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 buses 151 to 153, current sensors 161 to 163, a motor control circuit 170, and a gate driver circuit 180 in a housing 100.

[0032] Here, as described above, the high voltage DC power supplied from the high voltage power supply 30 is supplied to the switching elements 141 to 143 via the anode bus 111 and the cathode bus 112. The switching elements 141 to 143 generate high frequency switching current and voltage when switching, so an X capacitor 130 is generally used to smooth the current. Figure 1 Although not shown in the figure, a plurality of capacitors having a capacitance of about several tens of microfarads are connected in parallel. Here, the anode side terminal of the X capacitor 130 is connected to the anode bus 111, and the cathode side terminal of the X capacitor 130 is connected to the cathode bus 112. These anode bus 111 and cathode bus 112 are not particularly limited, but are copper plates made of copper. In addition, the Y capacitor 121 is connected between the anode bus 111 and the housing 100, and the Y capacitor 122 is connected between the cathode bus 112 and the housing 100, thereby reducing the common mode noise superimposed on the anode bus 111 and the cathode bus 112.

[0033] As the switching elements 141 to 143, semiconductor elements such as IGBT, MOSFET, SiC, etc. are generally used, and the desired voltage and current are generated by switching these semiconductor elements (switching between on and off). In addition, the switch outputs of the switching elements 141 to 143 are connected to the motor 40 from the AC buses 151 to 153 via the motor harness connector 103. The current sensors 161 to 163 are respectively installed on the respective AC buses 151 to 153, and the current values ​​flowing through the respective AC buses 151 to 153 are provided to the motor control circuit 170 as AC current monitoring signals 182.

[0034] The motor control circuit 170 that receives the AC current monitoring signal 182 generates a PWM signal and supplies it to the gate driving circuit 180. The gate driving circuit 180 inputs the gate driving signal 181 to the gate terminals of the switching elements 141 to 143 to operate the switching elements 141 to 143.

[0035] In the power conversion device 10 constructed in this way, the switching elements 141 to 143 are switched by the gate drive signal 181 from the gate drive circuit 180, and the anode voltage and the cathode voltage are periodically output from the AC bus 151 to 153, thereby being periodically in the on state / off state, so that the voltage / current in the anode bus 111 and the cathode bus 112 changes and noise is generated.

[0036] Figure 2 to Figure 4 is a diagram showing an example of the configuration of the power conversion device 10 .

[0037] Figure 2: is an exploded stereoscopic diagram showing an example of the structure of the power conversion device 10 involved in the present embodiment. In this figure, when the power conversion device 10 is unfolded, the Y capacitors 121~122, the X capacitors 130, and the switching elements 141~143 are stored in the bottom of the box-shaped casing 100 after the cover is removed. The anode bus 111 and the cathode bus 112 are stacked in isolation and connected to the terminals of the Y capacitors 121~122 and the X capacitors 130. Moreover, the anode bus 111 and the cathode bus 112 as the high voltage part are connected to the input terminals of the switching elements 141~143 as the high voltage part through the connecting screws 191~196. The connecting screws 191~196 are the connecting parts for electrically connecting the anode bus 111, the cathode bus 112 and the switching elements 141~143. In Figure 2 Due to the nature of the exploded view, not all engaging screws can be shown, but Figure 1 The anode bus 111, cathode bus 112 and switch elements 141 to 143 are joined at six locations. The circuit formed by the anode bus 111, cathode bus 112, joining screws (joining parts) 191 to 196 and switch elements 141 to 143 is referred to as a second circuit.

[0038] In order to suppress the high-frequency noise generated by the switching operation of the switching elements 141 to 143 as the high-voltage part from propagating to the motor control circuit 170 as the low-voltage part in the power conversion device 10, the metal base plate 200 is located on the upper part of the second circuit as the high-voltage part. In addition, the circuit board 300 on which the motor control circuit 170 and the like are arranged is located on the upper part of the metal base plate 200.

[0039] The circuit board 300 is provided with Figure 1 The motor control circuit 170, the gate drive circuit 180, the first substrate ground pattern 310 and the second substrate ground pattern 320 are shown. The first substrate ground pattern 310 and the second substrate ground pattern 320 are not electrically connected to each other on the circuit substrate 300. Here, the motor control circuit 170 is a circuit that operates with a low voltage source provided from the low voltage power supply 20, and uses the first substrate ground pattern 310 as a reference ground. The motor control circuit 170 on the circuit substrate 300 is referred to as a first circuit.

[0040] On the other hand, the gate driving circuit 180 is a circuit connected to the switching elements 141 to 143 as a high voltage section, and belongs to the high voltage section, and therefore is not based on the first substrate ground pattern 310 .

[0041] In addition, the metal base plate 200 has an opening 210 for avoiding contact with the joint screws 191 to 196, and the noise propagates to the low voltage portion through the opening 210. The four corners of the opening 210 are provided with bosses (second substrate ground pattern connection bosses 231 to 234) for electrically connecting to the circuit substrate 300 located above the metal base plate 200, and the bosses are electrically connected to the second substrate ground pattern 320 of the circuit substrate 300. For example, the following methods can be assumed for the electrical connection method: a method of directly contacting the second substrate ground pattern connection bosses 231 to 234 without applying a protective film to the second substrate ground pattern 320, a method of clamping a gasket, a method of contacting by a spring, a screw stop, etc., but this is not limited in the present embodiment.

[0042] Furthermore, the metal base plate 200 has substrate fixing bosses 221 to 226 for fixing the circuit substrate 300 , and the metal base plate 200 and the first substrate ground pattern 310 of the circuit substrate 300 are connected via the substrate fixing bosses 221 , 222 , 225 , and 226 .

[0043] Figure 3 1 is a cross-sectional projection diagram showing an example of the structure of the power conversion device 10 according to the present embodiment. Figure 2 The cross-sectional projection diagram when viewed along the arrow 500 shown in the figure is not a plane of a certain straight line, but a diagram projected in the depth direction in order to explain the structure of the power conversion device 10. Figure 1 and Figure 2 The low voltage connector 101, the high voltage connector 102, the motor harness connector 103, the anode bus 111, the cathode bus 112, the Y capacitors 121-122, the switch elements 141-143, the gate drive signal 181, the joint screws 191-196, the metal base plate 200, the opening 210, the substrate fixing sleeves 221-226, the second substrate ground pattern connection bosses 231-234, the circuit substrate 300, the first substrate ground pattern 310, and the second substrate ground pattern 320 have been described, and the above description is omitted in this figure. In addition, Figure 3 As described above, the first circuit mounting area 171 on the circuit substrate 300 is an area where a low-voltage circuit centered on the motor control circuit 170 is mounted, and the second circuit mounting area 183 is an area where a high-voltage circuit centered on a circuit composed of the anode bus 111, the cathode bus 112 and the connecting screws (connecting parts) 191 to 196 and the switching elements 141 to 143 is mounted.

[0044] The metal base plate 200 is provided between the second circuit and the circuit substrate 300, and has an opening 210 corresponding to the joint screws (joints) 191 to 196. The housing 100 accommodates the circuit substrate 300, the second circuit, and the metal base plate 200, and is electrically connected to the second substrate ground pattern 320 of the circuit substrate 300 and the metal base plate 200. The joint of the second circuit is arranged correspondingly to the second substrate ground pattern 320 via the opening 210 of the metal base plate 200. In addition, "arranged correspondingly" means that the joint of the second circuit and the second substrate ground pattern 320 are in a positional relationship corresponding to each other, and the opening 210 of the metal base plate 200 is located between the two. In addition, "arranged correspondingly" includes the following mode: the joint of the second circuit and the second substrate ground pattern 320 are arranged correspondingly to each other, and the opening 210 of the metal base plate 200 is located between the two. “Arranged correspondingly” also includes the following: when viewed from a direction perpendicular to the mounting surface of the circuit substrate 300, the joint portion of the second circuit, the region without the metal base plate 200, such as the opening 210, and the second substrate ground pattern 320 are arranged in a manner that at least a portion overlaps. In addition, the metal cover 400 forms a part of the housing 100 in the power conversion device 10.

[0045] Here, reference Figure 3 The structure around the opening 210 of the metal base plate 200 will be described in more detail. As one of the performance indicators for the power conversion device 10, the shell size can be cited, and the constraints in the height direction also become strict. In this case, the metal base plate 200 and the second circuit composed of the anode bus 111 and the cathode bus 112, and the switching elements 141 to 143, that is, the high-voltage part, need to be isolated and configured at the minimum distance required for insulation. In this case, in the mounting area 183 of the second circuit, since the height of the screw heads of the joining screws 191 to 196 that join the anode bus 111 and the cathode bus 112 to the switching elements 141 to 143 must be avoided to ensure the insulation distance from the metal base plate 200, in other words, the volume required for the joint portion is required, and therefore, the metal base plate 200 is provided. Figure 3 The second substrate ground pattern connection bosses 231 to 234 may be located at the end of the opening 210 or may be located at a position away from the end of the opening 210, for example, about 10 mm.

[0046] Figure 4 FIG. 2 is a plan view showing an example of the periphery of the opening 210 of the metal base plate 200 of the power conversion device 10 according to the present embodiment. Figures 1 to 3The anode bus line 111, cathode bus line 112, Y capacitors 121-122, switch elements 141-143, engaging screws 191-196, opening 210, second substrate ground pattern connection bosses 231-234, and second substrate ground pattern 320 have already been described, and the above description is omitted in this figure.

[0047] use Figure 4 The positional relationship between the opening 210 of the metal base plate 200, the second substrate ground 320 of the circuit substrate 300, and the second substrate ground pattern connection bosses 231 to 234 will be described in more detail. First, the opening 210 of the metal base plate 200 is used to maintain the insulation distance with the joint screws 191 to 196, and the size of the opening 210 is determined according to the insulation distance. The second substrate ground pattern connection bosses 231 to 234 are arranged to be in contact with the outer sides of the four corners of the opening 210 of the metal base plate 200, and the second substrate ground pattern 320 is arranged in the same position and size as the rectangle formed by the second substrate ground pattern connection bosses 231 to 234. The second substrate ground pattern 320 is connected to the metal base plate 200 via the second substrate ground pattern connection bosses 231 to 234 and other connection members, and the metal base plate 200 is connected to the housing 100.

[0048] In the power conversion device 10 according to the present embodiment, the second substrate ground pattern 320 is formed wider than the size of the opening 210 provided in the metal base plate 200, so that the second substrate ground pattern 320 is formed in a shape covering the opening 210. With this structure, even if the opening 210 is provided on the metal base plate 200 so as to avoid the joint portion connecting the anode bus 111, the cathode bus 112, and the switching elements 141 to 143 to maintain the insulation distance to the metal base plate 200, the following power conversion device 10 can be provided, which can suppress the increase in the amount of noise propagating from the high voltage portion to the low voltage portion such as the first substrate ground pattern 310 and the mounting area 171 of the first circuit.

[0049] In addition, in the power conversion device 10 involved in this embodiment, the second substrate ground pattern 320, which is a part of the substrate pattern, is used as a shielding plate against electromagnetic noise, thereby providing the following power conversion device: the additional countermeasure components can be minimized, and the increase in the amount of noise propagating from the high voltage part to the low voltage part such as the first substrate ground pattern 310 and the mounting area 171 of the first circuit can be suppressed at a low cost.

[0050] [Second embodiment]

[0051] Below, refer to Figure 5-6 The second embodiment of the present invention is described in detail. Figure 1The circuit configuration diagram showing the configuration of the power conversion device 10 and the configuration of the motor drive system to which the power conversion device 10 is applied is also the same in this embodiment. Figure 5 as well as Figure 6 In Figure 1 to Figure 4 The same reference numerals are used to designate the same places, and description thereof will be omitted.

[0052] Figure 5 1 is an exploded perspective view showing an example of the structure of the power conversion device 10 according to the present embodiment. Figure 2 The power conversion device 10 according to the first embodiment shown is different in that a second substrate ground pattern connecting wall 235 is formed instead of the second substrate ground pattern connecting bosses 231 to 234 .

[0053] As in the first embodiment, the metal base plate 200 has an opening 210 for avoiding contact with the joint screws 191 to 196, that is, the joint portion, and noise is transmitted to the low voltage portion through the opening 210. Around the opening 210, there is a wall (second substrate ground pattern connection wall 235) for electrically connecting to the circuit substrate 300 located on the upper part of the metal base plate 200, and the wall is electrically connected to the second substrate ground pattern 320 of the circuit substrate 300. For example, the following methods can be assumed for the electrical connection method: a method of directly contacting the second substrate ground pattern connection wall 235 without applying a protective film to the second substrate ground pattern 320, a method of clamping a gasket, a method of contacting by a spring, a screw stop, etc., but it is not limited in this embodiment.

[0054] Figure 6 1 is a top view showing an example of the periphery of the opening 210 of the metal base plate 200 of the power conversion device 10 according to the present embodiment. Figure 4 The power conversion device 10 according to the first embodiment shown is different in that a second substrate ground pattern connecting wall 235 is formed instead of the second substrate ground pattern connecting bosses 231 to 234 .

[0055] Reference Figure 6The positional relationship between the opening 210 of the metal base plate 200, the second substrate ground 320 of the circuit substrate 300, and the second substrate ground pattern connection wall 235 is described in more detail. First, the opening 210 of the metal base plate 200 corresponds to the joint screws 191 to 196 and is used to maintain the insulation distance with the joint screws 191 to 196. The size of the opening 210 is determined according to the insulation distance. The second substrate ground pattern connection wall 235 is arranged to be in contact with the outer sides of the four corners of the opening 210 of the metal base plate 200, and the second substrate ground pattern 320 is arranged in the same position and size as the rectangle formed by the second substrate ground pattern connection wall 235. The second substrate ground pattern 320 is connected to the metal base plate 200 via the second substrate ground pattern connection wall 235 and the like, and the metal base plate 200 is connected to the housing 100.

[0056] In the power conversion device 10 according to the present embodiment, the second substrate ground pattern 320 is formed wider than the size of the opening 210 provided in the metal base plate 200, so that the second substrate ground pattern 320 is formed in a shape that covers the opening 210 without a gap. With this structure, even if the opening 210 is provided on the metal base plate 200 so as to avoid the joint portion connecting the anode bus 111, the cathode bus 112, and the switching elements 141 to 143 to maintain the insulation distance to the metal base plate 200, the following power conversion device 10 can be provided, which can suppress the increase in the amount of noise propagating from the high voltage portion to the low voltage portion such as the first substrate ground pattern 310 and the mounting area 171 of the first circuit.

[0057] [Third Embodiment]

[0058] Below, refer to Figure 7 to Figure 9 The third embodiment of the present invention will be described in detail. Figure 1 The circuit configuration diagram showing the configuration of the power conversion device 10 and the configuration of the motor drive system to which the power conversion device 10 is applied is also the same in this embodiment. Figure 7 to Figure 9 In Figure 1 to Figure 6 The same reference numerals are used to designate the same places, and description thereof will be omitted.

[0059] Figure 7 1 is an exploded perspective view showing an example of the structure of a power conversion device 10 according to a third embodiment of the present invention. Figure 5The power conversion device 10 according to the second embodiment shown is different in that the metal base plate 200 has a shape that is present at a position covering at least the anode bus line 111 and the cathode bus line 112, and is not present on the upper part of the switching elements 141 to 143. Regarding this shape, for example, it is assumed that the shapes of the switching elements 141 to 143 interfere with the metal base plate 200, or the number of signal connections between the switching elements 141 to 143 and the circuit board 300 is large.

[0060] In addition, similarly to the first and second embodiments, the metal base plate 200 has an opening 210 for avoiding contact with the joint screws 191 to 196, that is, the joint portion, and noise propagates to the low voltage portion through the opening 210. Around the opening 210, a wall (second substrate ground pattern connection wall 235) for electrically connecting to the circuit substrate 300 located on the upper part of the metal base plate 200 is arranged in a U-shape, and is electrically connected to the second substrate ground pattern 320 of the circuit substrate 300. For example, the following methods can be assumed for the electrical connection method: a method of directly contacting the second substrate ground pattern connection wall 235 without applying a protective film to the second substrate ground pattern 320, a method of clamping a gasket, a method of contacting by a spring, a screw stop, etc., but it is not limited in this embodiment.

[0061] Figure 8 1 is a cross-sectional projection diagram showing an example of the structure of the power conversion device 10 according to the present embodiment. Figure 7 The cross-sectional projection diagram when viewed along the arrow 500 shown in FIG. 1 is not a plane of a certain straight line, but a diagram projected in the depth direction in order to illustrate the structure of the power conversion device 10. Figure 5 The power conversion device 10 according to the second embodiment shown in the figure is different in that, as shown in FIG. Figure 7 As described above, the metal base plate 200 is cut to the left end of the switching elements 141 to 143 , and the U-shaped second substrate ground pattern connection wall 236 surrounds the opening 210 in a U-shape.

[0062] Fig. 9 1 is a top view showing an example of the periphery of the opening 210 of the metal base plate 200 of the power conversion device 10 according to the present embodiment. Figure 6 The power conversion device 10 according to the second embodiment shown is different in that the metal base plate 200 is reduced in size to form a U-shaped second substrate ground pattern connecting wall 236 instead of the second substrate ground pattern connecting wall 235 .

[0063] Reference Fig. 9The positional relationship between the opening 210 of the metal base plate 200, the second substrate ground 320 of the circuit substrate 300, and the second substrate ground pattern connection wall 236 is described in more detail. First, the opening 210 of the metal base plate 200 corresponds to the joint screws 191 to 196 and is used to maintain the insulation distance with the joint screws 191 to 196. The size of the opening 210 is determined according to the insulation distance. The U-shaped second substrate ground pattern connection wall 236 is arranged to be in contact with the outer sides of the four corners of the opening 210 of the metal base plate 200, and there is no wall on the side of the switch elements 141 to 143. In addition, the second substrate ground pattern 320 has an area that is large enough relative to the rectangle formed by the second substrate ground pattern connection wall 236 and the opening 210. The second substrate ground pattern 320 is connected to the metal base plate 200 via the second substrate ground pattern connection wall 236, and the metal base plate 200 is connected to the housing 100.

[0064] In the power conversion device 10 according to the present embodiment, the second substrate ground pattern 320 is made wider than the opening 210 provided in the metal base plate 200, so that the second substrate ground pattern 320 is formed in a shape covering the opening 210. With this structure, even if the opening 210 is provided in the metal base plate 200 so as to avoid the joint portion connecting the anode bus 111, the cathode bus 112 and the switching elements 141 to 143 to maintain the insulation distance from the metal base plate 200, the power conversion device 10 can be provided, which can suppress the increase in the amount of noise propagating from the high voltage portion to the low voltage portion such as the first substrate ground pattern 310 and the mounting area 171 of the first circuit.

[0065] In addition, in the power conversion device 10 involved in this embodiment, the following power conversion device can be provided: even if the area of ​​the metal base plate 200 is reduced, the increase in the amount of noise propagating from the high voltage part to the low voltage part such as the first substrate ground pattern 310 and the mounting area 171 of the first circuit can be suppressed.

[0066] According to the above-described embodiment, the following effects can be obtained.

[0067] (1) The power conversion device 10 includes: a circuit substrate 300 having a first substrate ground pattern 310 (first ground) 310 constituting a ground of a first circuit (motor control circuit 170) and a second substrate ground pattern (second ground) 320 formed to be electrically isolated from the first ground 310; a second circuit (anode bus 111, cathode bus 112, switching elements 141 to 143) formed with joint screws (joint portions) 191 to 196; a metal base plate 200 provided between the second circuit and the circuit substrate 300 and having openings 210 corresponding to the joints 191 to 196; and a housing 100 accommodating the circuit substrate 300, the second circuit, and the metal base plate 200, being electrically connected to the second ground 320 of the circuit substrate 300 and the metal base plate 200, wherein the joint portions 191 to 196 of the second circuit are arranged corresponding to the second ground 320 via the openings 210 of the metal base plate 200. This can suppress the influence of noise propagating through the opening of the metal base plate 200 .

[0068] The present invention is not limited to the above-mentioned embodiments. As long as the features of the present invention are not impaired, other modes that can be considered within the scope of the technical concept of the present invention are also included in the scope of the present invention. For example, the above-mentioned embodiments are detailed descriptions for the purpose of explaining the present invention in an understandable manner, and the present invention is not necessarily limited to including all the structures described. In addition, a part of the structure of a certain embodiment may be replaced with the structure of other embodiments, and in addition, the structure of other embodiments may be added to the structure of a certain embodiment. In addition, other structures may be added, deleted, or replaced with a part of the structure of each embodiment.

[0069] The disclosures of the following priority basic applications are incorporated herein by reference.

[0070] Japanese Patent Application 2019-125886 (filed on July 5, 2019)

[0071] Description of symbols

[0072] 10 Power conversion device

[0073] 20 Low voltage power supply

[0074] 30 High Voltage Power Supply

[0075] 40 Electric Motor

[0076] 100 Shell

[0077] 101 Low Voltage Connector

[0078] 102 High Voltage Connector

[0079] 103 Motor wiring harness connector

[0080] 111 Anode bus

[0081] 112 Cathode bus

[0082] 121, 122Y capacitors

[0083] 130X Capacitor

[0084] 141, 142, 143 Switching elements

[0085] 151, 152, 153 AC bus

[0086] 161, 162, 163 current sensor

[0087] 170 Motor Control Circuit

[0088] 171The first circuit mounting area

[0089] 180 gate drive circuit

[0090] 181 Gate drive signal

[0091] 182AC current monitoring signal

[0092] 183 Second circuit mounting area

[0093] 191~196 Joint screws

[0094] 200 metal base plate

[0095] 210 opening

[0096] 221~226 Base plate fixing sleeve

[0097] 231-234 second substrate ground pattern connection bosses

[0098] 235 Second substrate ground pattern connection wall

[0099] 236 U-shaped second substrate ground pattern connection wall

[0100] 300 circuit board

[0101] 310 first substrate ground pattern

[0102] 320 second substrate ground pattern

[0103] 400 metal cover.

Claims

1. A power conversion device, characterized in that: include: a circuit substrate having a first ground constituting a ground of a first circuit and a second ground formed electrically separate from the first ground; a second circuit formed with a junction; a metal bottom plate, the metal bottom plate being disposed between the second circuit and the circuit substrate and having an opening portion corresponding to the joint portion; as well as a housing that accommodates the circuit substrate, the second circuit, and the metal bottom plate, and is electrically connected to the second ground of the circuit substrate and the metal bottom plate, The opening is configured to ensure a volume for the joint. The joint portion of the second circuit is arranged corresponding to the second ground via the opening portion of the metal base plate.

2. The power conversion device according to claim 1, characterized in that: The joint portion of the second circuit is arranged to face the second ground via the opening portion of the metal base plate.

3. The power conversion device according to claim 1, characterized in that: When viewed from a direction perpendicular to the mounting surface of the circuit substrate, the second circuit, the region without the metal base plate, and the second ground are formed to at least partially overlap.

4. The power conversion device according to claim 1, characterized in that: At least a portion of the periphery of the opening of the metal base plate is connected to the second ground of the circuit board via a connecting member.

5. The power conversion device according to claim 4, characterized in that: The periphery of the opening of the metal base plate is connected to the second ground of the circuit board via the wall-shaped connecting member.

6. The power conversion device according to claim 4 or 5, characterized in that: The second ground of the circuit substrate is connected to the housing via the connection member and through the metal bottom plate.

7. The power conversion device according to claim 1, characterized in that: The junction portion is a junction site that connects the anode bus line, the cathode bus line, and the switching element.

8. The power conversion device according to claim 7, characterized in that: The first circuit includes a low voltage motor control circuit. The second circuit includes an anode bus line as a high voltage, a cathode bus line, and a switching element.

9. The power conversion device according to claim 7 or 8, characterized in that: The metal base plate is disposed at a position covering at least the anode bus line and the cathode bus line.

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