Power Conversion Equipment

Abstract

To provide a power conversion device that can achieve both thinness and reliability.SOLUTION: A power conversion device comprises: an inverter circuit configured by a plurality of switching elements; a first capacitor and a second capacitor connected in parallel to the inverter circuit; a control circuit part that controls the inverter circuit; and a connection conductor part that connects between the first capacitor and the second capacitor. A conductive member is arranged between the control circuit part and the connection conductor part.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] As background art of the present invention, the following Patent Document 1 discloses a configuration in which control circuits (gate terminals) are arranged on the left and right in order to reduce abrupt current changes (surges) during switching. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-156310 A Summary of the Invention [Problem to be solved by the invention]

[0004] In consideration of the configuration of Patent Document 1, it is necessary to meet customer requests for miniaturization while also suppressing magnetic interference, and therefore an object of the present invention is to provide a power conversion device that is both thin and reliable. [Means for solving the problem]

[0005] The power conversion device includes an inverter circuit composed of a plurality of switching elements, a first capacitor and a second capacitor connected in parallel to the inverter circuit, a control circuit unit that controls the inverter circuit, and a connecting conductor unit that connects the first capacitor and the second capacitor, and a conductive member is arranged between the control circuit unit and the connecting conductor unit. Effect of the Invention

[0006] According to the present invention, it is possible to provide a power conversion device that is both thin and reliable. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a power conversion device having a configuration according to the present invention, and FIG. 2 is a view showing a state where a housing cover is removed; [Diagram 2] A circuit diagram of the power conversion device of FIG. 1 and a diagram explaining the movement of current in the main circuit. [Diagram 3] FIG. 2 is a diagram for explaining the configuration of a switching element of the power conversion device of FIG. 1; [Figure 4] FIG. 4 is a perspective view showing the connection between the switching element and the main circuit board in FIG. 3; [Diagram 5] 2 is a cross-sectional view taken along line AA of the power converter shown in FIG. 1 according to the first embodiment of the present invention; [Figure 6] FIG. 6 is a diagram for explaining the movement of the resonant current in FIG. 5. [Figure 7] A diagram explaining the induced current and magnetic flux in FIG. [Figure 8] 1 is a cross-sectional view of a power converter according to a second embodiment of the present invention; [Figure 9] Figure 8 shows the housing [Figure 10] 11 is a top cross-sectional view of a power converter according to a third embodiment of the present invention; FIG.

[0008] 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.

[0009] 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.

[0010] FIG. 1 is an overall perspective view of a power conversion device having a configuration according to the present invention, with a case cover removed.

[0011] The housing 2 of the power conversion device has a DC input terminal 16 that supplies a DC current to an inverter circuit provided inside the housing 2, an AC conductor 19 that outputs an AC current from the inverter circuit to an external motor (not shown), a refrigerant inlet 17 that supplies a refrigerant for cooling the inverter circuit to the inside of the housing 2, and a control signal input / output terminal 18 that transmits a control signal of the inverter circuit to an external control device. A part of the control signal input / output terminal 18 protrudes from the housing 2 in order to connect to a peripheral device of the housing 2. The housing 2 seals the inside, thereby preventing foreign objects and water from entering the inverter circuit from the outside. The housing 2 is made of aluminum, iron, or the like.

[0012] Inside the housing 2, there are mounted a first capacitor 1 which is a capacitor that smoothes the DC current input from the DC input terminal 16, a main circuit unit 3 which converts the DC current into AC current, a cooler 13 which is a refrigerant water passage that cools the main circuit unit 3, and a control circuit unit 7 which controls the inverter circuit based on commands input from an external control device.

[0013] FIG. 2 is a circuit diagram of the power conversion device of FIG. 1 and a diagram for explaining the movement of current in the main circuit.

[0014] The main circuit section 3 of the inverter circuit is composed of a DC input terminal 16, a second capacitor 8, an IGBT element 5a, a diode element 5b, and an AC conductor 19. The first capacitor 1 is connected in parallel to the positive and negative electrodes of the DC input terminal 16.

[0015] The IGBT element 5a is connected in series with the diode element 5b. The IGBT element 5a and the diode element 5b are connected in parallel with the second capacitor 8. The IGBT element 5a converts DC current into AC current by being turned on or off based on a signal from the control circuit 7. The IGBT element 5a, the diode element 5b, and the second capacitor 8 are configured as a unit for each of the three phases to configure a three-phase inverter.

[0016] A transient current 10a such as a diode recovery current generated when the IGBT element 5a is turned on and off flows from the second capacitor 8 through the path indicated by the dotted line as shown in the figure.

[0017] Furthermore, a resonant current 10 generated due to the wiring inductance of the connecting conductor 4 connecting the first capacitor 1 and the second capacitor 8 and the main circuit wiring member 3a flows through the path indicated by the thick black line as shown in the figure.

[0018] A capacitor with a large capacitance, such as a film capacitor, is used as first capacitor 1, and is configured with insulating resin covering the periphery and terminals. First capacitor 1 is connected to DC input terminal 16 via main circuit wiring member 3a.

[0019] Fig. 3 is a diagram for explaining the configuration of a switching element of the power conversion device of Fig. 1. Fig. 4 is a perspective view showing the connection between the switching element of Fig. 3 and a main circuit board.

[0020] A first lead frame 6a is electrically connected to the top surface of the IGBT element 5a, and a second lead frame 6b is electrically connected to the bottom surface by a joining member such as solder, and the top and bottom surfaces are cooled by the above-mentioned cooler 13. Terminals are provided at the ends of the first lead frame 6a and the second lead frame 6b, respectively, and are electrically connected to the main circuit wiring member 3a by solder or the like. The main circuit wiring member 3a is a substrate on which the lead frames are mounted, and a printed circuit board, copper bus bar, or the like is used.

[0021] A third lead frame 6c is electrically connected to the upper surface of the diode element 5b, and a fourth lead frame 6d is electrically connected to the lower surface by a joining member such as solder, and the upper and lower surfaces are cooled by a cooler 13 described below. Terminals are provided at the ends of the third lead frame 6c and the fourth lead frame 6d, respectively, and are electrically connected to the main circuit wiring member 3a by solder or the like.

[0022] The second capacitor 8 is electrically connected to the IGBT element 5a and the diode element 5b via the main circuit wiring member 3a. The second capacitor 8 is disposed between the IGBT element 5a and the diode element 5b, thereby shortening the path length of the wiring pattern of the main circuit wiring member 3a.

[0023] FIG. 5 is a cross-sectional view taken along line AA of the power converter of FIG. 1 according to the first embodiment of the present invention.

[0024] The main circuit section 3 is composed of a plurality of switching elements 5, a first capacitor 1, a second capacitor 8, a main circuit wiring member 3a, and a sealing resin 9. The switching elements 5 may be the above-mentioned IGBT elements 5a, diode elements 5b, MOSFET elements, or the like. The main circuit section 3 is provided with conductive members such as lead frames 6 (the first lead frame 6a to the fourth lead frame 6d described above in FIG. 3), and the switching elements 5 and the lead frames 6 are electrically connected by a joining material such as solder. The lead frames 6 are electrically connected to the main circuit wiring member 3a by soldering, welding, or the like.

[0025] The second capacitor 8 is a small capacitor with excellent frequency characteristics such as a ceramic capacitor, and supplies a transient current immediately after the switching element 5 switches from on to off or from off to on. The second capacitor 8 is connected in parallel with the first capacitor 1, and is disposed at a position where the wiring inductance between the second capacitor 8 and the IGBT element 5a and the diode element 5b is smaller than that of the first capacitor 1. The first capacitor 1 and the second capacitor 8 are connected in parallel with the inverter circuit.

[0026] The sealing resin 9 covers the first capacitor 1, the multiple switching elements 5, the lead frame 6, and the main circuit wiring member 3a, thereby preventing foreign matter from entering the main circuit portion 3.

[0027] The conductive member 2 is the same as the housing 2 described in FIG. 1 and is made of aluminum, iron, copper, or the like. The conductive member 2 can also be used as a fixing member for the first capacitor 1, the main circuit section 3, and the control circuit section 7. The conductive member 2 can also improve heat dissipation performance by contacting heat-generating components such as the main circuit section 3. In addition, the conductive member 2 has an uneven shape around the second capacitor 8, the main circuit section 3, the control circuit section 7, and the first capacitor 1 in accordance with the difference in height between the components. This allows the conductive member 2 to be placed close to each current path passing through the second capacitor 8, the main circuit section 3, and the control circuit section 7, respectively, and improves the effect of canceling out the magnetic flux, which will be described later.

[0028] The control circuit unit 7 is connected to the switching element 5 via a connector, the main circuit wiring member 3a, wire bonding, etc., and controls the on / off of the switching element 5. The control circuit unit 7 is equipped with a gate drive circuit that drives the gate of the switching element 5, a motor control circuit that generates a gate signal according to the rotation speed and torque of the motor, a power supply circuit that supplies power necessary for the operation of each control circuit, and the like.

[0029] The connecting conductor portion 4 is a terminal of the first capacitor 1 and is connected to the main circuit wiring member 3a, through which a resonant current 10 (described below) flows, which is generated due to the wiring inductance existing between the first capacitor 1 and the second capacitor 8.

[0030] FIG. 6 is a diagram for explaining the movement of the resonant current in FIG.

[0031] The second capacitor 8 is disposed in the vicinity of the switching elements 5 in order to reduce the wiring inductance of the current path formed by the multiple switching elements 5, and is connected in parallel to the first capacitor 1 via the main circuit wiring member 3a.

[0032] The first capacitor 1 supplies a steady current while the switching element 5 is on or off. At this time, since there is wiring inductance in the electric wiring connecting the first capacitor 1 and the second capacitor 8, a resonant current 10 is generated between the first capacitor 1 and the second capacitor 8.

[0033] FIG. 7 is a diagram for explaining the induced current and the magnetic flux in FIG.

[0034] A portion of the conductive member 2 is disposed between the connection conductor 4 connecting the first capacitor 1 and the second capacitor 8 and the control circuit unit 7. As a result, an induced current 11 is generated in the conductive member 2 due to the resonant current 10 flowing through the connection conductor 4. Furthermore, the magnetic flux 12a generated by the induced current 11 cancels out the magnetic flux 12b of the resonant current 10. As a result, it is possible to suppress the magnetic flux 12b of the resonant current 10 flowing through the connection conductor 4 from magnetically interfering with the control circuit unit 7. This makes it possible to realize stable operation of the control circuit unit 7.

[0035] Similarly to the induced current 11 caused by the above-mentioned resonant current 10, a transient current 10a flowing between the switching element 5 and the second capacitor 8 in the main circuit wiring member 3a also generates an induced current in the conductive member 2 arranged opposite to the upper and lower surfaces of the main circuit wiring member 3a. This induced current reduces the wiring inductance of the path of the transient current 10a. Furthermore, the induced current generated in the conductive member 2 suppresses leakage of magnetic flux caused by the transient current 10a.

[0036] Second embodiment FIG. 8 is a cross-sectional view of a power conversion device according to the second embodiment of the present invention.

[0037] The cooler 13 is made of a material with excellent thermal conductivity such as aluminum or copper, and the heat dissipation surface area is increased by providing fins, and the cooling performance can be improved by cooling air or water supplied from the outside. The cooler 13 can be provided on both the top and bottom surfaces of the main circuit unit 3 to improve the cooling performance of the inverter circuit. The cooler 13 is in contact with the lead frame 6 via an insulating member. The insulating member is coated with heat dissipation grease or the like to improve adhesion between the lead frame 6 and the cooler 13. The gate terminal 14 is located on the control circuit unit 7 side.

[0038] As a result, by providing conductive coolers 13 above and below the inverter circuit, especially above and below the switching elements 5 that generate a large amount of heat, not only is it possible to improve the cooling performance and reduce the size of the inverter circuit, but it is also possible, similar to the conductive member 2 described above, to cancel out the magnetic flux of the resonant current with the magnetic flux generated by the induced current caused by the resonant current flowing through the connecting conductor portion 4, thereby making it possible to suppress magnetic interference between the control circuit portion 7 and the connecting conductor portion 4.

[0039] FIG. 9 is a diagram of FIG. 8 with a housing added.

[0040] The first capacitor 1, the cooler 13, the main circuit section 3, and the control circuit section 7 are fixed to the bottom surface of the housing 2. The housing 2 can be arranged so that the gap between the housing 2 and the cooler 13 is narrowed, thereby further improving the magnetic interference reduction effect. In addition, by placing the housing 2 close to the connecting conductor 4, the wiring inductance can be reduced, and the above-mentioned resonance current can be suppressed. At this time, by providing an insulating heat dissipation member in the gap between the housing 2 and the connecting conductor 4, the cooling performance of the connecting conductor 4 can also be improved.

[0041] Furthermore, first capacitor 1 is fixed to housing 2 via an insulating heat dissipation member, and cooler 13 is also fixed to housing 2 via a similar heat dissipation member, so that heat generated in first capacitor 1 can be released via housing 2 to the coolant flowing in cooler 13. As a result, the connecting conductor 4 and the upper and lower surfaces of cooler 13 are covered with conductive housing 2, so that the magnetic flux of the resonant current that could not be canceled by cooler 13 alone can be canceled by the magnetic flux of the induced current generated in conductive housing 2.

[0042] (Third embodiment) FIG. 10 is a top cross-sectional view of a power converter according to a third embodiment of the present invention.

[0043] The refrigerant inlet 17 provided in the housing 2 is connected to an external refrigerant supply device such as a fan or a pump, and refrigerants such as cooling air, cooling water, and cooling oil are supplied to the inside of the housing 2. The refrigerant inlet 17 is also connected to the cooler 13, and the connection point is sealed with a sealing member such as an O-ring. The refrigerant inlet 17 is arranged in a direction perpendicular to the direction in which the first capacitor 1, the main circuit unit 3, and the control circuit unit 7 are arranged, and on the side of the cooler 13. This makes it possible to shorten the length of the refrigerant flow path while avoiding interference with other components such as the first capacitor 1 and the main circuit unit 3. Furthermore, by arranging the refrigerant inlet 17 on the side of the cooler 13, the entire cooling unit is made thinner.

[0044] According to the above-described first to third embodiments of the present invention, the following advantageous effects are achieved.

[0045] (1) The power conversion device includes an inverter circuit configured with a plurality of switching elements, a first capacitor 1 and a second capacitor 8 connected in parallel to the inverter circuit, a control circuit unit 7 that controls the inverter circuit, and a connection conductor unit 4 that connects the first capacitor 1 and the second capacitor 8, and a conductive member 2 is disposed between the control circuit unit 7 and the connection conductor unit 4. In this way, a power conversion device that is both thin and reliable can be provided.

[0046] (2) The conductive member 2 is a cooler 13 that cools the inverter circuit. This not only improves the cooling performance and reduces the size of the inverter circuit, but also cancels the magnetic flux of the resonant current by the magnetic flux generated by the induced current caused by the resonant current flowing through the connecting conductor 4.

[0047] (3) In the power conversion device, the conductive members 2 are provided on the upper and lower surfaces of the connection conductor 4 and the cooler 13. In this way, the magnetic flux of the resonant current that could not be canceled by the cooler 13 alone is canceled by the magnetic flux of the induced current generated in the conductive housing 2.

[0048] (4) The power conversion device has refrigerant inlet 17 on the side of cooler 13. This makes it possible to shorten the length of the refrigerant flow path while avoiding interference with other components such as first capacitor 1 and main circuit unit 3. Furthermore, by arranging refrigerant inlet 17 on the side of cooler 13, the entire cooling unit can be made thinner.

[0049] 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]

[0050] 1 First Capacitor 2 Housing (conductive material) 3 Main circuit section 3a Main circuit wiring material 4. Connecting conductor 5 Switching elements 5a IGBT element 5b Diode element 6 Lead Frame 6a First lead frame 6b Second lead frame 6c Third lead frame 6d 4th lead frame 7 Control circuit section 8 Second Capacitor 9 Sealing resin 10 Resonant current 10a transient current 11 Induced current 12a Magnetic flux (induced current side) 12b Magnetic flux (resonant current side) 13 Cooler 14 Gate terminal 16 DC input terminal 16a DC input terminal connection 17 Refrigerant inlet 18 Control signal input / output terminal 19 AC Conductor

Claims

1. an inverter circuit including a plurality of switching elements; a first capacitor and a second capacitor connected in parallel with the inverter circuit; A control circuit for controlling the inverter circuit; a connection conductor portion connecting the first capacitor and the second capacitor, a conductive member is disposed between the control circuit portion and the connection conductor portion; the conductive member is a cooler that cools the inverter circuit, The conductive member is provided on the upper and lower surfaces of the connection conductor and the cooler. Power conversion equipment.

2. The power conversion device according to claim 1, A refrigerant inlet is provided on the side of the cooler. Power conversion equipment.

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