Power converter, method for manufacturing a power converter

Abstract

To provide an electric power conversion system which achieves both low noise and low cost, and a method for manufacturing the electric power conversion system.SOLUTION: An electric power conversion system comprising a power module having a switching element for converting DC power into AC power, comprises: a DC bus bar for supplying the DC power to the switching element; a metal housing for housing the switching element; and a capacitor for connecting the DC bus bar and the housing, wherein the capacitor and the housing are electrically connected by a first connecting member which is a conductive adhesive.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a power conversion device and a method for manufacturing the power conversion device.

Background Art

[0002] Due to the resonance of the Y capacitor mounted in the power conversion device, a large amount of common mode noise leaks into the battery system. As a result, there may be a problem of not meeting the EMC regulations (noise standards). As a countermeasure against such a problem, for example, in Patent Document 1 below, a semiconductor device is disclosed in which an inductor is connected to a water channel by a conductive sheet, and the capacitance of an insulating layer and the inductance of the inductor are adjusted to reduce noise.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, as a countermeasure against the resonance of the Y capacitor, in order to provide a large resistance, for example, there are problems such as the need to change the physical property values to increase the inefficiency of the connection member of the Y capacitor, or even when measures are taken to reduce noise by inserting a damping resistor in series, since the resistance is mounted using a PCB board, the cost increases. In addition, even when there is no damping resistor, the GND terminal of the Y capacitor is connected to the housing via a welding fitting, and there is also a concern about an increase in the cost of the welding fitting and the mounting.

[0005] An object of the present invention is to provide a power conversion device and a method for manufacturing the power conversion device that achieve both low noise and low cost.

Means for Solving the Problems

[0006] A power conversion device according to a first aspect of the present invention is a power conversion device comprising a power module having a switching element that converts DC power to AC power, the power conversion device comprising a DC busbar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing, wherein the capacitor and the housing are electrically connected by a first connecting member which is a conductive adhesive. The first connecting member is filled into a non-conductive first adhesive container. . A power conversion device according to a second aspect of the present invention is a power conversion device comprising a power module having a switching element that converts DC power to AC power, the power conversion device comprising a DC busbar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing, wherein the capacitor and the housing are electrically connected by a first connecting member which is a conductive adhesive, and the housing has a connecting member filling portion which fills the first connecting member. This invention 3 The power conversion device according to the present invention is a power conversion device comprising a power module having a switching element that converts DC power to AC power, the device comprising a DC busbar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing, wherein the housing has a recess, the recess has an uneven surface, and the capacitor and the housing are electrically connected by filling the recess with a first connecting member which is a conductive adhesive. Furthermore, the power conversion device of the present invention comprises a DC busbar that supplies DC power to a switching element that converts DC power to AC power, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing, wherein the housing has a stepped portion that protrudes to the upper part, the capacitor and the stepped portion are electrically connected by a first connecting member which is a thermosetting resin and conductive adhesive filled in a first adhesive container, and the capacitor and the housing are connected by a second connecting member which is filled in a filling portion formed in a part of the housing different from the stepped portion. te Next, 1 contact Connecting member and 2nd contact A manufacturing method is employed in which the connecting components are heated simultaneously. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a power conversion device and a method for manufacturing a power conversion device that achieve both low noise and low cost. [Brief explanation of the drawing]

[0008] [Figure 1] Diagram illustrating the power conversion device and other drive-related components installed in the vehicle. [Figure 2] Functional block diagram of the power converter shown in Figure 1. [Figure 3] Diagram of the filter circuit included in the power converter shown in Figure 2. [Figure 4] Diagram illustrating a filter circuit according to one embodiment of the present invention. [Figure 5] Cross-sectional view AA in Figure 4 [Figure 6] An explanatory diagram of a resin cover provided in a filter circuit according to one embodiment of the present invention. [Figure 7] Modified example of the first connecting material container according to one embodiment of the present invention [Figure 8] Figure 7 shows the filter circuit applied to the filter. [Figure 9] First variation [Figure 10] Second variation [Figure 11] Third variation [Figure 12] Fourth variation

[0009] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] (An embodiment of the present invention and the overall configuration of the apparatus) (Figure 1) The vehicle is equipped with a power conversion device 200, a battery system 136, a motor generator MG (Motor Generator), and a transmission TM (Transmission). The power conversion device 200 has a filter circuit 1, a smoothing capacitor 500, a power module 150, a driver circuit 174, and a control circuit section 172 inside.

[0012] The battery system 136 stores the electrical energy required for the vehicle to run and supplies DC power to the power conversion device 200. The DC connector 138 is a connector used to input the DC power of the battery system 136 to the power conversion device 200.

[0013] The filter circuit 1 filters the noise generated in the power conversion device 200 and prevents the noise from mixing into the battery system 136. The smoothing capacitor 500 supplies stable DC power to the inverter circuit section of the power module 150 by smoothing the DC power from the battery system 136.

[0014] The inverter circuit section of the power module 150 has switching elements that convert DC power into AC power. The control circuit section 172 receives commands from a higher-level control device (not shown) via the control connector 430 and transmits drive signals to the driver circuit 174 on the driver board. The driver circuit 174 drives the power module 150 according to the signal from the control circuit section 172 on the control board. As a result, the switching elements of the inverter circuit section of the power module 150 operate to output an alternating current to the motor generator MG.

[0015] The AC terminal 420 transmits the three-phase alternating current output from the power module 150 to the motor generator MG. The power generated by the motor generator MG is transmitted to the tires via the transmission TM.

[0016] (Figure 2) The current sensor 180 is installed near the AC busbar 421 to detect the AC current output from the power module 150 to the motor generator MG. The current value detected by the current sensor 180 is input to the control circuit unit 172 and used for feedback processing. The motor control connector 420a receives the signal from the motor generator MG1 and transmits the signal to the control circuit unit 172 through the motor control wiring 435.

[0017] (Figure 3) The filter circuit 1 includes a Y capacitor 4 connected to a positive busbar 5a that supplies DC power to a switching element, a Y capacitor 4 connected to a negative busbar 5b, and a first connecting member 7 that connects each Y capacitor 4 to the housing 104. The Y capacitors 4 serve as noise reduction capacitors for the power conversion device 200.

[0018] (Figures 4 and 5) The filter circuit 1 comprises a DC busbar 5 that supplies DC power to a switching element, a metal housing 104 that houses the switching element, and a Y capacitor 4 that connects the DC busbar 5 and the housing 104. The Y capacitor 4 and the housing 104 are electrically connected by a first connecting member 7, which is a conductive adhesive.

[0019] Each Y capacitor 4 has a GND terminal 9 (first terminal) and an HV terminal 6 (second terminal). The HV terminal 6 of one Y capacitor 4 is connected to the positive busbar 5a of the HV busbar (DC busbar), and the HV terminal 6 of the other Y capacitor 4 is connected to the negative busbar 5b. The GND terminal 9 of each Y capacitor 4 is connected to the first connecting member 7. The first connecting member 7 is a conductive adhesive, which is filled in the first adhesive container 10.

[0020] The housing 104 has a stepped portion 104a that protrudes from the top. The bottom surface of the first adhesive container 10 is in contact with the stepped portion 104a. The first adhesive container 10 is non-conductive and has a through hole through which the GND terminal 9 of the Y capacitor 4 and the positioning pin 8 of the housing 104 pass. The positioning pin 8 is connected to the stepped portion 104a through the through hole of the first adhesive container 10. As a result, the return current to the housing 104 flows from the GND terminal 9 to the positioning pin 8 inside the first connecting member 7, while the current returning from the positioning pin 8 to the noise source (switching source) while diffusing throughout the housing 104 has a component in the opposite direction. This cancels out the magnetic fields with the currents of each other, resulting in low inductance. As a result, noise can be reduced.

[0021] When the first adhesive container 10 is filled with the first connecting member 7, which is a conductive adhesive, the positioning pin 8 and the GND terminal 9 are electrically connected. This allows the noise from the positive busbar 5a and the negative busbar 5b to be bypassed to the housing 104, thereby filtering the noise. Furthermore, this enables both the positioning of the adhesive container 10 in the housing 104 and the connection between the first connecting member 7 and the housing 104.

[0022] The housing 104 is also connected to the Y capacitor 4 in parts other than the stepped portion 104a, and is connected to the bottom surface of the Y capacitor 4 (the lower surface in Figure 5) by the second connecting member 7a. In this way, the Y capacitor 4 is fixed to the housing 104.

[0023] The first connecting member 7, which is filled into the first adhesive container 10, acquires resistance when it is filled into the container 10 and electrically connected between the GND terminal 9 and the housing 104. By adjusting the amount of this first connecting member 7 filled, a desired damping resistance value can be obtained without degrading noise performance. This is because the first connecting member 7, as a conductive adhesive, has a material-specific resistivity, and this can be used to adjust the damping resistance value to the desired level. In addition, by being filled into the container 10, the first connecting member 7 is prevented from adhering to unnecessary parts of the housing 104.

[0024] The first connecting member 7 may be formed by mixing two types of liquids. That is, after positioning in the housing 104 of the first adhesive container 10, the first connecting member 7 can be formed by mixing the two types of adhesives inside the container 10. Therefore, a step of mixing the two types of first connecting members 7 in advance and then filling them into the container 10 becomes unnecessary, improving the overall flexibility of the process and increasing productivity.

[0025] Furthermore, the present invention is a device comprising a DC busbar 5 composed of a positive busbar 5a and a negative busbar 5b that supply DC power to a switching element that converts DC power to AC power, a metal housing 104 that houses the switching element, and a Y capacitor 4 that connects the DC busbar 5 and the housing 104. In the manufacturing process of this device, a stepped portion 104a protruding from the top is formed on the housing 104, the Y capacitor 4 and the stepped portion 104a are electrically connected by a first connecting member 7 which is a thermosetting resin and conductive adhesive filled in a first adhesive container 10, and the Y capacitor 4 and the housing 104 are connected by a second connecting member 7a which is filled in a filling portion 19 formed in a part of the housing 104 different from the stepped portion 104a. te Next, a process is employed in which the first connecting member 7 and the second connecting member 7a are heated simultaneously.

[0026] By adopting this manufacturing process, the resin curing process by heating is completed in one step, thus preventing a prolonged assembly time. For the second connecting member 7a, for example, FIPG (Formed In Place Gasket) can be used. The second connecting member 7a can use the same conductive adhesive as the first connecting member 7, rather than a different type of adhesive, thus reducing costs.

[0027] According to the configuration of the present invention, welding fittings for the GND terminal 9, which were conventionally used for the Y capacitor 4, are no longer required. Furthermore, by mounting the Y capacitor 4 in the housing 104 at low cost, resonance can be attenuated. This makes it possible to provide a power conversion device 200 that achieves both low noise and low cost.

[0028] (Figure 6) The first adhesive container 10 may have a resin lid 12 on top of it as a lid for contamination prevention, thereby sealing the first connecting member 7 inside the container 10. This also prevents the first connecting member 7 from leaking or splashing out of the container 10. Furthermore, the vibration resistance of the container 10 is improved, and adhesion to the GND terminal 9 and the positioning pin 8 is maintained.

[0029] Furthermore, by placing the first adhesive container 10 on the reference line 11 (on a plane) formed by the upper surface of the Y capacitor 4 and the upper surface of the stepped portion 104a, the placement of the first adhesive container 10 can be limited on the housing 104, and the first connecting member 7 inside the container 10 is filled so that it accumulates on a plane, preventing uneven accumulation. As a result, the positioning pin 8 and the GND terminal 9 can be bonded to each other by the first connecting member 7 at approximately the same height inside the container 10. In addition, the stress on the first connecting member 7 due to vibration is distributed, and improved vibration resistance can be expected.

[0030] (Figures 7 and 8) As shown in the figure, the first adhesive container 10 may have a plurality of internal walls 10b, and the first connecting member 7 may be filled in the first adhesive container 10 so as to be folded back along the plurality of internal walls 10b. In this way, in order to adjust the damping resistance value by the amount of the first connecting member 7 filled into the container 10, the damping resistance value may be adjusted by the length of the filled portion in the container 10, while considering the balance between increased resistance and low inductance. Furthermore, with this configuration, the currents flowing through the first connecting member 7 in opposite directions at the folded portion of the container 10 cancel out the magnetic flux, contributing to a reduction in inductance. In other words, it becomes possible not only to adjust the resistance value but also to achieve both increased resistance and low inductance.

[0031] The diagram shows that the first adhesive container 10 is provided with a through hole 13 for inserting a positioning pin 8 for fixing it to the housing 104, and a through hole 14 for the GND terminal 9. By providing these two through holes 13 and 14 in the container 10, the first adhesive container 10 can be positioned on the housing 104, making mounting easier. Furthermore, the diameter of the through hole 13 may be made 2 mm or more larger than the diameter of the positioning pin 8 in order to intentionally leak the internal first connecting member 7 to the bottom of the adhesive container 10 and fix the adhesive container 10 to the housing 104 and the Y capacitor 4 over a larger area. This improves the vibration resistance of the container 10.

[0032] (First variation) (Figure 9) In the filter circuit 1, the first terminal 9 of the Y capacitor 4 is inserted through a through hole in the first adhesive container 10, and the second terminal 6 is inserted through a through hole formed in the second adhesive container 10a, which is connected to the DC busbar 5. At this time, the second terminal 6 and the DC busbar 5 are electrically connected by the first connecting member 7 filled in the second adhesive container 10a. In this way, by providing the first connecting member 7 and container 10a for the connection between the HV terminal 6 and the DC busbars 5a and 5b, welding becomes unnecessary for the connection between the HV terminal 6 and the DC busbars 5a and 5b.

[0033] Furthermore, the second adhesive container 10a may be formed as part of the resin 15 that molds the DC busbars 5a and 5b, thereby reducing the cost of newly manufacturing the second adhesive container 10a and lowering overall costs.

[0034] (Second variation) (Figure 10) A fixing member 17 is placed between the first adhesive container 10 and the stepped portion 104a of the housing 104. If the position of the container 10 is determined by something other than the positioning pin 8 of the housing 104, the positioning pin 8 may be replaced with a screw 16 and fixed to the stepped portion 104a. This further enhances the fixation of the first adhesive container 10 to the housing 104.

[0035] (Third variation) (Figure 11) The housing 104 may have a configuration that includes a connection member filling section 19 for filling with the first connection member 7. By having only a recess in the housing 104 that can hold (fill) the conductive first connection member 7, the GND terminal 9 of the Y capacitor 4 is electrically connected to and fixed to the housing 104 through the first connection member 7. The housing 104 also has minute irregularities 18. If it is desired to adjust the damping resistance by increasing or decreasing the resistance between the GND terminal 9 and the housing 104, this can be achieved by increasing or decreasing the surface area by increasing or decreasing the minute irregularities 18. In this way, even without an adhesive container 10, noise from the DC busbars 5a and 5b can be dissipated.

[0036] (Fourth variation) (Figure 12) The GND terminal 9 and HV terminal 6 of the Y capacitor 4 may be bent to form an L-shape (key-shaped) GND terminal 9a and HV terminal 6a. For example, if this L-shaped Y capacitor 4 is applied in the configuration shown in Figure 11, the welding area between the positive busbar 5a and the HV terminal 6 can be increased. Furthermore, since the GND terminal 9a is closer to the housing 104, it becomes possible to reduce the number of first connecting members 7. In addition, the Y capacitor 4 in the housing 104 becomes more resistant to vibrations in the left-right direction of the drawing.

[0037] When this L-shaped Y capacitor 4 is applied to the configurations shown in Figures 4 and 5, the through-hole in the adhesive container 10 only needs to be large enough for the GND terminal 9 to pass through. Because it is not a straight terminal, it has a structure perpendicular to the direction of vibration, respectively, in response to stresses generated by vertical or horizontal vibrations, thus improving vibration resistance.

[0038] According to the embodiment of the present invention described above, the following effects are achieved.

[0039] (1) A power converter 200 comprising a power module 150 having a switching element that converts DC power to AC power, comprising a DC busbar 5 that supplies DC power to the switching element, a metal housing 104 that houses the switching element, and a Y capacitor 4 that connects the DC busbar 5 and the housing 104, wherein the Y capacitor 4 and the housing 104 are electrically connected by a first connecting member 7 which is a conductive adhesive. In this way, a power converter 200 that achieves both low noise and low cost can be provided.

[0040] (2) The first connecting member 7 is filled into a non-conductive first adhesive container 10. This allows the damping resistance to be adjusted to a desired value.

[0041] (3) The housing 104 has a stepped portion 104a that protrudes from the top, and the bottom surface of the first adhesive container 10 is placed on a reference line 11 formed by the top surface of the Y capacitor 4 and the top surface of the stepped portion 104a. In this way, the first connecting member 7 can be filled evenly inside the container 10 without being unevenly distributed, and vibration resistance can be improved.

[0042] (4) The bottom surface of the first adhesive container 10 is in contact with the stepped portion 104a. This makes it possible to achieve low inductance and low noise.

[0043] (5) The first adhesive container 10 has a through hole 13 through which a positioning pin 8 for fixing to the housing 104 is inserted. This makes mounting easier.

[0044] (6) The diameter of the through hole 13 is 2 mm or more larger than the diameter of the positioning pin 8. This improves both stability and vibration resistance.

[0045] (7) The Y capacitor 4 has a first terminal 9 and a second terminal 6. The first terminal 9 is inserted through a through hole 14 in the first adhesive container 10, and the second terminal 6 is inserted through a through hole formed in the second adhesive container 10a, which is connected to the DC busbar 5. The second terminal 6 and the DC busbar 5 are electrically connected by a first connecting member 7 which is filled in the second adhesive container 10a. This eliminates the need for welding.

[0046] (8) The second adhesive container 10a is formed as part of the resin 15 that molds the DC busbar 5. This reduces the number of adhesive containers 10 and lowers costs.

[0047] (9) The first adhesive container 10 has a resin lid 12 on its top. This allows for measures to prevent contamination.

[0048] (10) The first adhesive container 10 has a plurality of internal walls 10b, and the first connecting member 7 is filled in the first adhesive container 10 so as to be folded back along the plurality of internal walls 10b. This reduces the inductance.

[0049] (11) The first adhesive container 10 is fixed to the stepped portion 104a by a screw 16. This allows for vibration countermeasures to be implemented.

[0050] (12) The housing 104 has a connecting member filling section 19 for filling with the first connecting member 7. This reduces the number of containers 10 and lowers costs.

[0051] (13) The power converter 200 comprises a DC busbar that supplies DC power to a switching element that converts DC power to AC power, a metal housing 104 that houses the switching element, and a Y capacitor 4 that connects the DC busbar 5 and the housing 104. A stepped portion 104a protruding from the top is formed on the housing 104, and the Y capacitor 4 and the stepped portion 104a are electrically connected by a first connecting member 7, which is a thermosetting resin and conductive adhesive filled in the first adhesive container 10, and the Y capacitor 4 and the housing 104 are electrically connected by a second connecting member 7a that is filled in a filled portion 19 formed in the housing 104 in a part different from the stepped portion 104a, and the first connecting member 7 and the second connecting member 7a are heated simultaneously. By adopting such a manufacturing method for the power converter 200, the process can be simplified and both low noise and low cost can be achieved.

[0052] (14) The first connecting member 7 is formed in the first adhesive container 10 by mixing two types of liquids. This limits the type of adhesive used for the first connecting member 7, thereby improving the flexibility of the assembly process.

[0053] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted. [Explanation of Symbols]

[0054] 1. Filter circuit 4 Y Capacitors 5 HV Busbar 5a Positive busbar 5b Negative busbar 6 HV terminal (2nd terminal) 6a L-shaped HV terminal 7. First connecting member 7a Second connecting member 8 positioning pins 9. GND terminal (Terminal 1) 9a L-shaped GND terminal 10. First adhesive container 10a Second adhesive container 10b internal wall 11. Reference line 12 Resin lid 13 Holes for positioning pins 14 holes for GND terminal 15 Mold resin 16 screws 17 Fixing member 18 Microscopic irregularities 19. Connecting member filling section 104 cabinets 104a Stepped section

Claims

1. A power conversion device comprising a power module having a switching element that converts DC power to AC power, The device comprises a DC busbar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing. The capacitor and the housing are electrically connected by a first connecting member which is a conductive adhesive. The first connecting member is filled into a non-conductive first adhesive container. Power converter.

2. A power conversion device according to claim 1, The housing has a stepped portion that protrudes from the top, The bottom surface of the first adhesive container is placed on a reference line formed by the upper surface of the capacitor and the upper surface of the stepped portion. Power converter.

3. A power conversion device according to claim 2, The bottom surface of the first adhesive container is in contact with the stepped portion. Power converter.

4. A power conversion device according to claim 1, The first adhesive container has a through hole through which a positioning pin for fixing it to the housing is inserted. Power converter.

5. A power conversion device according to claim 4, The diameter of the through hole is 2 mm or more larger than the diameter of the positioning pin. Power converter.

6. A power conversion device according to claim 4, The capacitor has a first terminal and a second terminal, The first terminal is inserted through the through hole of the first adhesive container. The second terminal is inserted through a through hole formed in the second adhesive container which is connected to the DC busbar. The second terminal and the DC busbar are electrically connected by the first connecting member, which is filled into the second adhesive container. Power converter.

7. A power conversion device according to claim 6, The second adhesive container is formed as part of the resin that molds the DC busbar. Power converter.

8. A power conversion device according to claim 1, The first adhesive container has a resin lid on top thereof. Power converter.

9. A power conversion device according to claim 1, The first adhesive container has a plurality of internal walls, The first connecting member is filled in the first adhesive container so as to be folded back along a plurality of the inner walls. Power converter.

10. A power conversion device according to claim 2, The first adhesive container is fixed to the stepped portion by a screw. Power converter.

11. A power conversion device comprising a power module having a switching element that converts DC power to AC power, The device comprises a DC busbar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing. The capacitor and the housing are electrically connected by a first connecting member which is a conductive adhesive. The housing has a connecting member filling section for filling the first connecting member. Power converter.

12. A power conversion device comprising a power module having a switching element that converts DC power to AC power, The device comprises a DC busbar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing. The housing has a recess, The recess has an uneven surface, The first connecting member, which is a conductive adhesive, is filled into the recess, thereby electrically connecting the capacitor and the housing. Power converter.

13. The device comprises a DC busbar that supplies DC power to a switching element that converts DC power to AC power, a metal housing that houses the switching element, and a capacitor that connects the DC busbar and the housing. A stepped portion is formed on the housing, which protrudes from the top. The capacitor and the stepped portion are electrically connected by a first connecting member, which is a thermosetting resin and conductive adhesive filled in a first adhesive container. The capacitor and the housing are connected by a second connecting member that is filled in a filling portion formed in the housing in a portion different from the stepped portion. The first connecting member and the second connecting member are heated simultaneously. A method for manufacturing a power conversion device.

14. A method for manufacturing a power converter according to claim 13, The first connecting member is formed by mixing two types of liquids in the first adhesive container. A method for manufacturing a power conversion device.

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