Electric power conversion system and method for manufacturing electric power conversion system

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 technology]

[0002] In a power conversion device, large common mode noise leaks into a battery system due to resonance of the Y capacitor mounted thereon. This can lead to a problem of not being able to meet EMC regulations (noise standards). As a countermeasure to this problem, for example, the following Patent Document 1 discloses a semiconductor device that has a configuration in which an inductor is connected to a water channel by a conductive sheet, thereby adjusting the capacitance of an insulating layer and the inductance of the inductor to reduce noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-223010 A Summary of the Invention [Problem to be solved by the invention]

[0004] Previously, in order to counter the resonance of the Y capacitor, it was necessary to change the physical properties of the connecting material of the Y capacitor to increase its resistivity in order to give it a large resistance, and even if a damping resistor was inserted in series to reduce noise, the resistor was mounted on a PCB board, which caused problems such as increased costs.In addition, even if there was no damping resistor, the GND terminal of the Y capacitor was connected to the housing via a welding metal fitting, and there was a concern that the costs of the welding metal fitting and mounting would increase.

[0005] An object of the present invention is to provide a power conversion device that achieves both low noise and low costs, and a method for manufacturing the power conversion device. [Means for solving the problem]

[0006] A power conversion device including a power module having a switching element that converts DC power into AC power, the device including a DC bus bar that supplies DC power to the switching element, a metal housing that accommodates the switching element, and a capacitor that connects the DC bus bar and the housing, the capacitor and the housing being electrically connected by a first connecting member that is a conductive adhesive. In addition, the power conversion device of the present invention includes a DC bus bar that supplies DC power to a switching element that converts the DC power into AC power, a metal housing that houses the switching element, and a capacitor that connects the DC bus bar and the housing, and adopts a manufacturing method in which a step portion that protrudes upward is formed in the housing, the capacitor and the step portion are electrically connected by a first connecting member that is a thermosetting resin and a conductive adhesive filled in a first adhesive container, the capacitor and the housing are electrically connected by a second connecting member that is filled in a filling portion formed in a part of the housing different from the step portion, and the first connecting member and the second connecting member are heated simultaneously. Effect of the Invention

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

[0008] [Figure 1] An explanatory diagram of a power conversion device and other components related to driving mounted on a vehicle. [Diagram 2] Functional block diagram of the power conversion device of FIG. 1 [Diagram 3] A configuration diagram of a filter circuit provided in the power conversion device of FIG. 2. [Figure 4] FIG. 2 is an explanatory diagram of a filter circuit according to an embodiment of the present invention. [Diagram 5] Cross section AA of Figure 4 [Figure 6]FIG. 1 is an explanatory diagram of a resin cover provided on a filter circuit according to an embodiment of the present invention. [Figure 7] A first connecting material container according to an embodiment of the present invention [Figure 8] Figure 7 applied to a filter circuit [Figure 9] First Modification [Figure 10] Second Variation [Figure 11] Third Modification [Figure 12] Fourth Variation

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component 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.

[0011] (One embodiment of the present invention and overall configuration of the device) (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 includes a filter circuit 1, a smoothing capacitor 500, a power module 150, a driver circuit 174, and a control circuit unit 172.

[0012] The battery system 136 stores electric 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 for inputting the DC power of the battery system 136 to the power conversion device 200.

[0013] The filter circuit 1 filters noise generated in the power conversion device 200, and prevents the noise from being mixed into the battery system 136. The smoothing capacitor 500 smoothes the DC power from the battery system 136, thereby supplying stable DC power to the inverter circuit unit of the power module 150.

[0014] The inverter circuit section of the power module 150 has a switching element that converts DC power to AC power. The control circuit section 172 receives a command from a higher-level control device (not shown) via the control connector 430 and transmits a drive signal to a driver circuit 174 on the driver board. The driver circuit 174 drives the power module 150 by the signal from the control circuit section 172 on the control board. This causes the switching element of the inverter circuit section of the power module 150 to operate and output an AC current to the motor generator MG.

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

[0016] (Figure 2) The current sensor 180 is installed near the AC bus bar 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 a 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 has a Y capacitor 4 connected to a positive bus bar 5a that supplies DC power to the switching element, a Y capacitor 4 connected to a negative bus bar 5b, and a first connection member 7 that connects each of the Y capacitors 4 to a housing 104. The Y capacitor 4 serves as a noise removal capacitor for the power conversion device 200.

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

[0019] The Y capacitors 4 have 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 a positive bus bar 5a of an HV bus bar (DC bus bar), and the HV terminal 6 of the other Y capacitor 4 is connected to a negative bus bar 5b. The GND terminals 9 of the Y capacitors 4 are each connected to a first connection member 7. The first connection member 7 is a conductive adhesive, and is filled in a first adhesive container 10.

[0020] The housing 104 has a step portion 104a that protrudes upward. The bottom surface of the first adhesive container 10 is in contact with the step 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 penetrate. The positioning pin 8 is connected to the step 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 connection member 7, while the current that returns to the noise source (switching source) while diffusing from the positioning pin 8 to the entire housing 104 has a component in the opposite direction. As a result, the magnetic fields are cancelled out by the currents, and the inductance can be reduced. As a result, the noise can be reduced.

[0021] The first adhesive container 10 is filled with the first connecting member 7, which is a conductive adhesive, so that the positioning pin 8 and the GND terminal 9 are electrically connected. This allows noise from the positive bus bar 5a and the negative bus bar 5b to be bypassed to the housing 104, thereby filtering the noise. This also allows 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 to be achieved.

[0022] The housing 104 is connected to the Y capacitor 4 also at a portion other than the step portion 104a, and is connected to the bottom surface of the Y capacitor 4 (the surface on the lower side in FIG. 5) by the second connection member 7a. In this way, the Y capacitor 4 is fixed to the housing 104.

[0023] The first connection member 7 filled in the first adhesive container 10 has resistance by being filled in the container 10 and electrically connecting between the GND terminal 9 and the housing 104. By adjusting the filling amount of this first connection member 7, a desired damping resistance value that does not deteriorate noise performance can be obtained. This is because the first connection member 7 has a resistivity inherent to the material as a conductive adhesive, and this can be utilized to adjust the damping resistance value to a desired value. Furthermore, by filling the container 10 with the first connection member 7, the first connection member 7 is prevented from adhering to unnecessary parts of the housing 104.

[0024] The first connection member 7 may be formed by mixing two types of liquid. That is, after the first adhesive container 10 is positioned in the housing 104, the two types of adhesives can be mixed in the container 10 to form the first connection member 7. This eliminates the need for a process in which the two types of first connection members 7 are mixed in advance and then filled into the container 10, improving the flexibility of the entire process and improving productivity.

[0025] The present invention also provides a device including a DC bus bar 5 composed of a positive bus bar 5a and a negative bus bar 5b that supply DC power to a switching element that converts DC power into AC power, a metal housing 104 that houses the switching element, and a Y capacitor 4 that connects the DC bus bar 5 and the housing 104. As a manufacturing process for this device, a process is adopted in which a step portion 104a that protrudes upward is formed in the housing 104, the Y capacitor 4 and the step portion 104a are electrically connected by a first connecting member 7 that is a thermosetting resin and a conductive adhesive filled in a first adhesive container 10, the Y capacitor 4 and the housing 104 are electrically connected by a second connecting member 7a that is filled in a filling portion 19 formed in a portion of the housing 104 different from the step portion 104a, and the first connecting member 7 and the second connecting member 7a are heated simultaneously.

[0026] By adopting such a manufacturing process, the resin curing process by heating is performed only once, so that the assembly time can be prevented from being long. For example, a FIPG (Formed In Place Gasket) is used as the second connection member 7a. The second connection member 7a can be made of the same conductive adhesive as the first connection member 7, instead of a different type of adhesive from that of the first connection member 7, so that the cost can be reduced.

[0027] According to the configuration of the present invention, there is no need for welding metal fittings for GND terminal 9 that have been used in the conventional Y capacitor 4. Furthermore, by mounting Y capacitor 4 in housing 104 at low cost, it is possible to attenuate resonance. This makes it possible to provide 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 the top as a cover for the container 10 to prevent contamination, thereby sealing the first connection member 7 within the container 10. This also makes it possible to prevent the first connection member 7 from leaking or scattering from 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 step portion 104a, not only can the arrangement of the first adhesive container 10 be limited on the housing 104, but the first connection member 7 in the container 10 is filled so as to accumulate on a plane, so that it does not accumulate unevenly. This allows the positioning pin 8 and the GND terminal 9 to be bonded to each other by the first connection member 7 at approximately the same height within the container 10. Furthermore, the stress of the first connection member 7 due to vibration is also dispersed, and improvement in vibration resistance can be expected.

[0030] (Fig. 7, Fig. 8) As shown in the figure, the first adhesive container 10 may have a plurality of internal walls 10b, and the first connection 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 connection member 7 filled in the container 10, the damping resistance value may be adjusted by the length of the filled portion in the container 10 while considering both an increase in resistance and a low inductance. In addition, by adopting such a configuration, the currents flowing through the first connection member 7 are in the opposite directions at the folded portion of the container 10, so that the magnetic flux is canceled and contributes to reducing the inductance. In other words, it is possible not only to adjust the resistance value but also to achieve both an increase in resistance and a low inductance.

[0031] The first adhesive container 10 is shown to have a through hole 13 for inserting the positioning pin 8 for fixing to the housing 104 and a through hole 14 for the GND terminal 9. By providing two through holes 13 and 14 in the container 10, the first adhesive container 10 can be positioned to the housing 104, making mounting easier. In addition, 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 allow the first connecting member 7 inside to leak 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 Modification) (Fig. 9) In the filter circuit 1, the first terminal 9 of the Y capacitor 4 is inserted into a through hole of the first adhesive container 10, and the second terminal 6 is inserted into a through hole formed in the second adhesive container 10a connected to the DC bus bar 5. At this time, the second terminal 6 and the DC bus bar 5 are electrically connected by the first connection member 7 filled in the second adhesive container 10a. In this way, by providing the first connection member 7 and the container 10a also for the connection between the HV terminal 6 and the DC bus bars 5a, 5b, welding is not required for the connection between the HV terminal 6 and the DC bus bars 5a, 5b.

[0033] In addition, the second adhesive container 10a may be formed as part of the resin 15 that molds the DC bus bars 5a, 5b, thereby reducing the cost of newly manufacturing the second adhesive container 10a and achieving lower costs.

[0034] (Second Modification) (Figure 10) A fixing member 17 is disposed between the first adhesive container 10 and the step 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 the container 10 may be fixed to the step portion 104a. This further improves the fixation of the first adhesive container 10 to the housing 104.

[0035] (Third Modification) (Fig. 11) The housing 104 may have a connection member filling portion 19 that fills the first connection member 7. Since the housing 104 has only a recess that can store (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 a minute uneven portion 18. When it is desired to adjust the damping resistance by increasing or decreasing the resistance value between the GND terminal 9 and the housing 104, this can be achieved by increasing or decreasing the minute uneven portion 18 to increase or decrease the surface area. In this way, even if the adhesive container 10 is not provided, noise from the DC bus bars 5a and 5b can be released.

[0036] (Fourth Modification) (Fig. 12) The GND terminal 9 and the HV terminal 6 of the Y capacitor 4 may be bent into an L-shape (hook shape) as the GND terminal 9a and the HV terminal 6a. For example, when the L-shaped Y capacitor 4 is applied to the configuration of FIG. 11, the welding area between the positive bus bar 5a and the HV terminal 6 can be increased. Furthermore, since the GND terminal 9a is closer to the housing 104, the first connection member 7 can be reduced. Furthermore, in the housing 104, the Y capacitor 4 becomes more resistant to shaking in the left-right direction in the drawing.

[0037] When this L-shaped Y capacitor 4 is applied to the configuration of Figures 4 and 5, the through hole of the adhesive container 10 can be made large enough to allow the GND terminal 9 to pass through. Since the terminal is not a straight line, the structure is perpendicular to the vibration direction, respectively, to the stress generated by vertical and horizontal vibrations, improving vibration resistance.

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

[0039] (1) A power conversion device 200 including a power module 150 having a switching element that converts DC power to AC power, the power conversion device 200 including a DC bus bar 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 bus bar 5 and the housing 104, the Y capacitor 4 and the housing 104 being electrically connected by a first connection member 7 that is a conductive adhesive. In this way, a power conversion device 200 that achieves both low noise and low cost can be provided.

[0040] (2) The first connection member 7 is filled in a non-conductive first adhesive container 10. In this way, the damping resistance can be adjusted to a desired value.

[0041] (3) Housing 104 has step 104a protruding upward, and the bottom surface of first adhesive container 10 is placed on reference line 11 formed by the upper surface of Y capacitor 4 and the upper surface of step 104a. This allows first connecting member 7 to be filled flatly inside container 10 without being biased, and improves vibration resistance.

[0042] (4) The bottom surface of the first adhesive container 10 is in contact with the step 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 the positioning pin 8 is inserted for fixing to the housing 104. This makes mounting easy.

[0044] (6) The diameter of the through hole 13 is 2 mm or more larger than the diameter of the positioning pin 8. This makes it possible to improve fixation properties 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 into a through hole 14 of the first adhesive container 10, the second terminal 6 is inserted into a through hole formed in a second adhesive container 10a connected to the DC bus bar 5, and the second terminal 6 and the DC bus bar 5 are electrically connected by a first connecting member 7 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 bus bar 5. This can reduce the number of adhesive containers 10, thereby reducing costs.

[0047] (9) The first adhesive container 10 has a resin lid 12 on its top. This makes it possible to implement measures against contamination.

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

[0049] (11) The first adhesive container 10 is fixed to the step portion 104a by the screw 16. This makes it possible to implement a vibration countermeasure.

[0050] (12) The housing 104 has a connection member filled portion 19 that is filled with the first connection member 7. This can reduce the number of containers 10 and lower the cost.

[0051] (13) The power converter 200 includes a DC bus bar that supplies DC power to a switching element that converts DC power into AC power, a metal housing 104 that houses the switching element, and a Y capacitor 4 that connects the DC bus bar 5 to the housing 104. Then, a step portion 104a that protrudes upward is formed in the housing 104, and the Y capacitor 4 and the step portion 104a are electrically connected by a first connection member 7 that is a thermosetting resin and a conductive adhesive filled in a first adhesive container 10, and the Y capacitor 4 and the housing 104 are electrically connected by a second connection member 7a that is filled in a filling portion 19 formed in a part of the housing 104 different from the step portion 104a, and the first connection member 7 and the second connection member 7a are heated at the same time. 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 connection member 7 is formed by mixing two types of liquid in the first adhesive container 10. By doing so, the type of adhesive for the first connection member 7 can be limited, improving the flexibility of the assembly process.

[0053] The present invention is not limited to the above-described embodiment, and various modifications and other configurations can be combined without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiment, and includes those in which some of the configurations are omitted. [Explanation of symbols]

[0054] 1. Filter circuit 4 Y Capacitors 5 HV busbar 5a Positive bus bar 5b Negative bus bar 6 HV terminal (2nd terminal) 6a L-shaped HV terminal 7 First connecting member 7a Second connecting member 8 Locating Pin 9 GND terminal (first terminal) 9a L-shaped GND terminal 10 First adhesive container 10a Second adhesive container 10b internal wall 11 Reference Line 12 Resin lid 13 Locating pin hole 14 GND terminal hole 15 Molding resin 16 Screws 17 Fixing member 18 Microscopic irregularities 19 Connection member filling section 104 Case 104a Step

Claims

1. A power conversion device including a power module having a switching element for converting DC power into AC power, a DC bus bar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC bus bar and the housing, The capacitor and the housing are electrically connected by a first connection member that is a conductive adhesive. Power conversion equipment.

2. The power conversion device according to claim 1, The first connection member is filled in a non-conductive first adhesive container. Power conversion equipment.

3. The power conversion device according to claim 2, The housing has a step portion protruding upward, A bottom surface of the first adhesive container is placed on a reference line formed by an upper surface of the capacitor and an upper surface of the step portion. Power conversion equipment.

4. The power conversion device according to claim 3, The bottom surface of the first adhesive container is in contact with the step portion. Power conversion equipment.

5. The power conversion device according to claim 2, The first adhesive container has a through hole through which a positioning pin for fixing the first adhesive container to the housing is inserted. Power conversion equipment.

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

7. The power conversion device according to claim 5, the capacitor has a first terminal and a second terminal; the first terminal is inserted into the through hole of the first adhesive container; the second terminal is inserted into a through hole formed in a second adhesive container connected to the DC bus bar, The second terminal and the DC bus bar are electrically connected by the first connection member filled in the second adhesive container. Power conversion equipment.

8. The power conversion device according to claim 7, The second adhesive container is formed as a part of the resin that molds the DC bus bar. Power conversion equipment.

9. The power conversion device according to claim 2, The first adhesive container has a resin lid on its top. Power conversion equipment.

10. The power conversion device according to claim 2, the first adhesive container having a plurality of interior walls; The first connection member is filled in the first adhesive container so as to be folded back along the plurality of inner walls. Power conversion equipment.

11. The power conversion device according to claim 3, The first adhesive container is fixed to the step portion by a screw. Power conversion equipment.

12. A power conversion device including a power module having a switching element for converting DC power to AC power, a DC bus bar that supplies the DC power to the switching element, a metal housing that houses the switching element, and a capacitor that connects the DC bus bar and the housing, The housing has a recess, The recess has an uneven portion, The capacitor and the housing are electrically connected by filling the recess with a first connection member that is a conductive adhesive. Power conversion equipment.

13. a DC bus bar that supplies DC power to a switching element that converts the DC power into AC power, a metal housing that houses the switching element, and a capacitor that connects the DC bus bar and the housing, A step portion protruding upward is formed on the housing, The capacitor and the step portion are electrically connected to each other by a first connection member, which is a thermosetting resin and a conductive adhesive filled in a first adhesive container; the capacitor and the housing are electrically connected to each other by a second connection member filled in a filling portion formed in a portion of the housing different from the step 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 conversion device according to claim 13, comprising the steps of: The first connection member is formed by mixing two types of liquid in the first adhesive container. A method for manufacturing a power conversion device.

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