The disclosure of Japanese Patent Application No. 2013-004630 filed on Jan. 15, 2013 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a power conversion device.
2. Description of Related Art
An electric vehicle includes a power conversion device that converts direct current power of a battery into alternate current power that is suitable for driving a motor for vehicle travel. A typical power conversion device is an inverter or a voltage converter. Because the power conversion device of the electric vehicle operates with large power, a large amount of heat may generated in the power conversion device. Meanwhile, compactness is demanded for a device for a vehicle. Both heat control and compactness are demanded for the power conversion device for the electric vehicle.
The large amount of heat may generated in devices, such as semiconductor elements and reactors, of the power conversion device. Examples of the semiconductor elements include power transistors such as IGBTs and power elements such as free wheel diodes that are parallelly connected with the power transistors. The reactor constitutes a voltage conversion circuit along with the semiconductor element. Japanese Patent Application Publication No. 2011-228426 (JP 2011-228426 A) suggests the power conversion device that compactly houses the semiconductor element, the reactor, and a cooling apparatus that cools these. The cooling apparatus of the power conversion device has a plurality of cooling plates that are alternately laminated with a plurality of flat-plate semiconductor modules containing semiconductor elements. Such a laminated body will hereinafter be referred to as “laminated unit”. The laminated unit has two coolant passages that pass through the plurality of cooling plates. In the laminated unit of JP 2011-228426 A, a coolant supply pipe and a coolant discharge pipe that are linearly aligned with the coolant passages are connected to the cooling plate positioned at an end in a laminating direction. The coolant supply pipe and the coolant discharge pipe extend in parallel with each other, and the reactor is disposed between the pipes.
Further, Japanese Patent Application Publication No. 2009-261125 (JP 2009-261125 A) discloses a technique related to cooling of the laminated unit and the reactor. A power conversion device of JP 2009-261125 A has the reactor disposed in the vicinity of the above-described coolant supply pipe and coolant discharge pipe. Incidentally, the power conversion device includes a large capacity capacitor for smoothing output current of the battery. In the technique of JP 2009-261125 A, a heat receiving plate is disposed between the reactor and the capacitor, and heat of the heat receiving plate is absorbed by the cooling plates of the laminated unit. Specifically, a heat dissipation plate is interposed between the pair of cooling plate in the laminated unit, and the heat dissipation plate and the heat receiving plate are connected together by a heat pipe. The heat of the capacitor is absorbed by the heat receiving plate, next transmitted to the heat dissipation plate through the heat pipe, and then transmitted to the cooling plates.
The present invention relates to cooling of a laminated unit and a reactor and provides a power conversion device that can reduce an influence of heat of the reactor on other electronic components.
A first aspect of the present invention provides a power conversion device including: a laminated unit; a reactor; a shield. In the laminated unit, flat-plate semiconductor modules and flat-plate cooling plates are laminated. The flat-plate semiconductor modules houses semiconductor elements. The shield is interposed between the reactor and electronic components. The shield has coolant passages which supply coolant to or discharge coolant from the laminated unit through the shield. An above configuration allows cooling of the shield by the coolant that passes through the coolant passages and reduction in an influence of heat of the reactor on other electronic components that are positioned on the opposite side of the shield.
In the power conversion device, a portion of the coolant passages may be integral with the shield. An above configuration improves heat transmission efficiency between coolant pipes constituting the coolant passages and the shield. Further, integral molding provides an advantage in an aspect of production cost.
in the power conversion device, the shield may include plurality of plates that are coupled together. In the power conversion device, the shield may contact the reactor. In the power conversion device, the shield contact an end surface of the laminated unit in a laminating direction.
In the power conversion device, the electronic components may be a capacitor module and a control board. The shield may be a cooling block. The cooling block may includes an upper plate and a side plate. The cooling block may has the coolant passages which supply coolant to or discharge coolant from the laminated unit through the coolant passages. The upper plate may be interposed between the reactor and the control board. The side plate may be interposed between the reactor and the capacitor module. In an above configurations, the shield is cooled by the cooling plate at an end of the laminated unit in the laminating direction. Because such shield can transmit heat to both of the cooling plate positioned at the end of the laminated unit and the coolant passages, the reactor can efficiently be cooled.
Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
A power conversion device 2 of an embodiment will be described with reference to drawings. The power conversion device 2 is installed in an electric vehicle 50 and converts direct current power of a battery 51 to alternate current power that is suitable for motor drive. An electric system (drive system) of the electric vehicle 50 will be described with reference to
A capacitor 52 for smoothing output current of the battery 51 is connected to an input side of the booster circuit 54. A capacitor 53 for smoothing output current of the booster circuit 54 is connected to an output side of the booster circuit 54, that is, an input side of the inverter circuit 55. Because large current flows through the capacitors 52, 53, the capacitors have large capacities and large physical volumes.
Output of the inverter circuit 55 is supplied to a motor 56. Output torque of the motor 56 is transmitted to drive wheels 58 via a differential gear 57. Although not shown in
A buck converter 59 other than the booster circuit 54 is connected to the battery 51. The buck converter 59 reduces the voltage of the battery 51 to a voltage suitable for an auxiliary device and supplies the voltage thereto. The “auxiliary device” is a generic name for a device such as a room lamp or a car navigation system that operates at a lower voltage than the output voltage of the battery 51 that stores power for travel.
A hardware configuration of the power conversion device 2 will be described.
The capacitor module 4 includes capacitors 52, 53 on the circuit of
The laminated unit 10 is a device in which the semiconductor elements operating on the output current of the battery are integrated. Specifically, in the laminated unit 10, a plurality of flat-plate semiconductor modules 14 that are the semiconductor elements molded with a resin and a plurality of flat-plate cooling plates 12 are laminated together. In the single semiconductor module 14, single and sets of several transistors and diodes (see
The laminated unit 10 is interposed and supported between a wall surface of the housing 3 and the cooling block 20. A plate spring 5 is inserted between the wall surface of the housing 3 and the laminated unit 10. The laminated unit 10 is pressurized in its laminating direction by the plate spring 5. The pressure in the laminating direction makes the semiconductor modules 14 and the cooling plates 12 that adjoin each other tightly fit together. This enhances heat transmission efficiency between the semiconductor modules 14 and the cooling plates 12.
A protrusion 8a provided on an upper surface of the reactor 8 contacts the upper plate 23. The heat of the reactor 8 is actively absorbed by the upper plate 23 via the protrusion 8a (that is, the cooling block 20 absorbs the heat via the protrusion 8a and the upper plate 23). The upper plate 23 is fixed to the reactor 8 by the protrusion 8a. That is, the cooling block 20 is fixed to the reactor 8 via the upper plate 23 and the protrusion 8a.
The cooling block 20 is supported by the reactor 8, and the reactor 8 is fixed to the housing 3. The cooling block 20 supports one end of the laminated unit 10 in the laminating direction. Specifically, the cooling block 20 directly contacts a cooling plate 12a positioned in one end section of the laminated unit 10 and thereby supports the laminated unit 10. Passages of the coolant are formed in the interior of the cooling block 20. The coolant supplied from the outside first passes through a space (described below) below the housing 3 and next the cooling block 20 and moves to the laminated unit 10. The coolant after cooling the semiconductor modules 14 in the laminated unit again passes through the cooling block 20 and then the space below the housing 3 and is discharged to the outside of the housing. The cooling block 20 is formed of aluminum or copper and transmits the heat of the reactor 8 contacting that to the coolant. In other words, the cooling block 20 cools the reactor 8. As described above, the cooling block 20 is also a portion of the “shield”.
The passage of the coolant will be described with reference to
The coolant that has passed through the cooling block 20 is supplied to the laminated unit 10. The coolant that has passed through the cooling plates 12 again returns to the cooling block 20. The coolant that has returned to the cooling block 20 moves to the lower space through the elbow pipe 22 that forms the portion of the cooling block 20. A section denoted by a reference symbol 3a in
As described above, in the power conversion device 2, the entering coolant cools the buck converter 59 on a lower side of the housing 3 and next moves to the cooling block 20. The coolant cools the reactor 8 in the cooling block 20 and blocks the heat of the reactor 8 so as to prevent the heat from influencing the control board 33 and the capacitor module 4. The shield (the upper plate 23, the side plate 24, and the cooling block 20) contribute to the heat blockage. The coolant thereafter moves to the laminated unit 10 and cools the semiconductor elements in the semiconductor modules 14. As described above, in the power conversion device 2, the coolant is allowed to move to various places, thereby cooling the plurality of components.
A configuration of the cooling block 20 that is the portion of the shield will next be described in detail.
Points to be noted about the technique described in the embodiment will be described. The technique disclosed in this specification is particularly characterized in the shield. The shield includes the cooling block 20, the upper plate 23 and the side plate 24. One of the characteristics is as follows. The coolant passes through the cooling block 20, and the cooling block 20 contacts and cools the reactor 8. At the same time, the cooling block 20 integrated with the upper plate 23, the side plate 24. The upper plate 23 and the side plate 24 extend between the reactor 8 and the other electronic components and thereby reduces an influence of the heat of the reactor 8 on the other electronic components. Typical examples of the other electronic components are the control board 33 and the capacitor module 4. In particular, the capacitor does not have high heat resistance, and the shield disclosed in this specification is thus effective. The cooling block 20 corresponds to the coupling section of the plurality of plates (the upper plate 23, the side plate 24) and serves as the portion of the shield.
The coolant passages are formed in the interior of the cooling block 20 that is the portion of the shield. In other words, the coolant passages that supply to or discharge from the laminated unit 10 pass through the interiors of the shield.
The coolant passages in accordance with the present invention include the supply pipe of coolant 13a, the discharge pipe of coolant 13b, the elbow pipe 21, and the coolant pipe 32 and serve as a generic name of a pipe through which the coolant passes. A portion of the coolant passages in accordance with the present invention may integrally be formed with the shield. For example, the portion of the coolant passages and the shield can integrally be fabricated by injection molding or the like with aluminum. In addition, the “shield” is not limited to a simple flat plate.
In the foregoing, specific examples of the present invention have been described in detail. However, those are merely illustrative and do not limit the claims. Techniques recited in the claims include modifications and variations of the specific examples described above. Technical elements described in this specification and the drawings provide technical usefulness by themselves or in various combinations and are not limited to the combinations recited in the claims in the application. Further, the techniques exemplified in this specification or the drawings can simultaneously achieve a plurality of objects, and achievement of a single object among those provides technical usefulness.
Number | Date | Country | Kind |
---|---|---|---|
2013-004630 | Jan 2013 | JP | national |