The present invention relates to a power converter, and particularly, to a power converter used for a hybrid vehicle or an electric vehicle.
A power semiconductor module used for a power converter, particularly, a power semiconductor module used for a hybrid vehicle or an electric vehicle is configured so that the power semiconductor module is immersed to a flow path forming body and many surfaces of the power semiconductor module function as cooling surfaces to improve a cooling efficiency (PTL 1).
In a case where such a cooling system is used, a pressure of a refrigerant flowing through a flow path formed in the flow path forming body makes the power semiconductor module be extracted from the flow path forming body and applies a stress to a terminal of the power semiconductor module. Accordingly, reliability of the power converter is deteriorated. To take measures against the deterioration of the reliability, the size and the cost of the power converter may be increased.
An object of the present invention is to improve reliability of a power converter while suppressing an increase in size and an increase in cost of the power converter.
A power converter according to the present invention includes a power semiconductor module and a flow path forming body which contains the power semiconductor module and forms a flow path through which a refrigerant flows. In the flow path forming body, a first opening which communicates one surface of the flow path forming body with the flow path is formed, and in the power semiconductor module, a first sealing surface which is formed along an insertion direction of the power semiconductor module into the flow path and faces the flow path forming body and a second sealing surface which is formed along the insertion direction and faces the flow path forming body are formed.
According to the present invention, reliability of a power converter can be improved while suppressing an increase in size and an increase in cost of the power converter.
An embodiment for carrying out the present invention will be described below with reference to the drawings.
Power semiconductor modules 300a to 300c form inverter circuits that respectively output alternating currents of a U phase, a V phase, and a W phase. A capacitor module 230 smooths a direct current transmitted to the power semiconductor modules 300a to 300c.
A bus bar assembly 240 transmits the direct current from the capacitor module 230 to the power semiconductor modules 300a to 300c. The bus bar assembly 240 includes a positive electrode side bus bar, a negative electrode side bus bar, and a molding material for supporting the positive electrode side bus bar and the negative electrode side bus bar. DC input bus bars 250P and 250N electrically connect a battery to the bus bar assembly 240.
A circuit board 260 in the present embodiment includes a control circuit unit which generates a control signal for controlling the power semiconductor modules 300a to 300c and a drive circuit unit which generates a drive signal for driving the power semiconductor modules 300a to 300c. Noted that only one of the control circuit unit and the drive circuit unit may be mounted on the circuit board 260.
A flow path forming body 200 is a box-like rectangular parallelepiped having a pair of short side wall portions and a pair of long side wall portions. The flow path forming body 200 contains the capacitor module 230, the power semiconductor modules 300a to 300c, the bus bar assembly 240, the DC input bus bars 250P and 250N, the circuit board 260, and the like.
It is possible that the flow path forming body 200 only fixes the power semiconductor modules 300a to 300c and that the other components such as the capacitor module 230 is contained in a casing different from the flow path forming body 200.
A casing lower cover 220 is assembled to cover a flow path forming body lower surface 200a. As a result, watertightness of a refrigerant flowing through a flow path 400 (refer to
A refrigerant inflow pipe 210IN and a refrigerant outflow pipe 210OUT are respectively inserted into a refrigerant inflow port 211IN and a refrigerant outflow port 211OUT of the flow path forming body 200, and the refrigerant is flowed in and out through the refrigerant inflow pipe 210IN and the refrigerant outflow pipe 210OUT.
A fixing plate 500 is fixed to the flow path forming body 200 while having contact with the power semiconductor modules 300a to 300c so that the power semiconductor modules 300a to 300c are not detached from the flow path forming body 200.
A circuit portion of the power semiconductor module 300a includes a power semiconductor element (IGBT, diode, and the like) included in a series circuit, a conductor member, an AC terminal, a DC positive terminal, a DC negative terminal, and the like. The power semiconductor element and the like are sealed with a resin material and form a sealing body 303.
The sealing body 303 is inserted into an insertion port 302 of a module case 301 via insulating paper and the like. The sealing body 303 is bonded to an inner wall of the module case 301. The module case 301 includes a first heat dissipation unit 305a and a second heat dissipation unit 305b of which areas are larger than the side surface, and the first heat dissipation unit 305a and the second heat dissipation unit 305b face each other. In the sealing body 303, the power semiconductor element (IGBT, diode, and the like) is arranged to be faced to the first heat dissipation unit 305a and the second heat dissipation unit 305b. In the present embodiment, heat dissipation fins 305c are arranged in the first heat dissipation unit 305a and the second heat dissipation unit 305b. Furthermore, it is not necessary for the heat dissipation fin 305c to have a tubular shape, and the heat dissipation fin 305c may have another shape, or it is possible that the first heat dissipation unit 305a and the second heat dissipation unit 305b do not include the heat dissipation fins 305c.
As illustrated in
The power semiconductor module 300a form first sealing surfaces 307 formed along an insertion direction from the first opening 401 to the flow path 400 and facing to each other. A first groove 306 to assemble a first sealing member 801 is provided in the module case 301. In the first groove 306, the first sealing surfaces 307 are formed which are formed along the insertion direction from the first opening 401 of the flow path forming body 200 to the flow path 400 and face each other. In the present embodiment, the first sealing surface 307 is formed in the first groove 306. However, the first sealing surface 307 may be formed on the other surface facing to the flow path forming body without providing the first groove 306.
In addition to the first sealing surface 307, in the power semiconductor module 300a, second sealing surfaces 309 are formed which are formed along the insertion direction from the first opening 401 of the flow path forming body 200 to the flow path 400 and face each other. In the present embodiment, a second groove 308 is formed on the opposite side of the first sealing surface 307 as sandwiching the first heat dissipation unit 305a and the second heat dissipation unit 305b which are heat dissipation surfaces of the power semiconductor module 300a and the heat dissipation fins 305c therebetween. The second sealing member 802 is arranged in the second groove 308. In the second groove 308, the second sealing surfaces 309 are formed which are formed along the insertion direction from the first opening 401 of the flow path forming body 200 to the flow path 400 and face each other.
A first projecting portion 304 is formed to be projected from the first heat dissipation unit 305a and the second heat dissipation unit 305b and functions as a flange. In addition, the first groove 306 is formed in a part of the first projecting portion 304 so that the first groove 306 is longer than the second groove 308.
The first sealing member 801 ensures watertightness by having contact with the first sealing surface 307 and the flow path forming body 200. In the present embodiment, the first sealing surface 307 is formed in the first groove 306. However, other surface facing to the flow path forming body such as a side surface of the first projecting portion 304 may be directly formed as the first sealing surface 307 without providing the first groove 306. In the present embodiment, the first sealing member 801 is assembled to the power semiconductor module 300a. However, the first sealing member 801 may be assembled to the flow path forming body 200.
The second sealing member 802 ensures watertightness by having contact with the second sealing surface 309 and the flow path forming body 200. In the present embodiment, the second sealing surface 309 is formed in the second groove 308. However, the second sealing surface 309 may be formed on the other surface facing to the flow path forming body without providing the second groove 308. In the present embodiment, the second sealing member 802 is assembled to the power semiconductor module 300a. However, the first sealing member 801 may be assembled to the flow path forming body 200. By providing the second sealing member 802, as illustrated in
Fluid in a sealed container has properties such that the same amount of an internal force is perpendicularly applied to each of all pixels in a unit area of all the surfaces of the container when the force is applied at a single point, regardless of the shape of the container. In a case where the power semiconductor module 300d to which the second sealing member 802 is not assembled is assembled to the flow path forming body 200 and the flow path 400 is filled with the refrigerant, as illustrated in
If the forces applied to these surfaces are added, as illustrated in
In a case where the power semiconductor module 300a to which the second sealing member 802 is assembled is assembled to the flow path forming body 200 and the flow path 400 is filled with the refrigerant, as illustrated in
In comparison between
At this time, as illustrated in
In a case where the power semiconductor module 300e in which the second projecting portion 311 is formed is assembled to the flow path forming body 200 and the flow path 400 is filled with the refrigerant, as illustrated in
At this time, as the area of the flow path side wall 311a is closer to the area of the flow path side wall 304a, in the power semiconductor module 300e, the force applied to the flow path side wall 304a on the side of the first projecting portion along the direction of the extraction from the flow path forming body 200 is reduced. In other words, the rigidity of the fixing plate 500 to fix the power semiconductor module 300e can be lowered since the force applied to the flow path side wall 304a is reduced, and an increase in size and cost of the fixing plate 500 can be prevented.
Furthermore, in a case where the area of the flow path side wall 311a is the same as the area of the flow path side wall 304a, the force applied to the flow path side wall 311a is the same as the force applied to the flow path side wall 304a. That is, since a resultant force of the force applied to the flow path side wall 311a and the force applied to the flow path side wall 304a is zero, the fixing plate 500 can be made unnecessary.
In a case where the flow path forming body 200 is formed, for example, by die casting, to remove a mold after the material of the flow path forming body 200 is cured, the flow path wall 201 of the flow path forming body 200 has a tapered shape as illustrated in
However, as illustrated in
Therefore, even if the flow path wall 201 of the flow path forming body 200 has a tapered shape, the rigidity of the fixing plate 500 to fix the power semiconductor module 300e can be lowered since the force applied to the flow path side wall 304a is reduced, and the fixing plate 500 of the power semiconductor module can be prevented from being enlarged.
As illustrated in
In a case where the power semiconductor module 300f of which the flow path side wall 304a has an angle is assembled to the flow path forming body 200 and the flow path 400 is filled with the refrigerant, as illustrated in
As illustrated in
That is, in a case where the flow path side wall 304a forms a plane having an angle (for example, obtuse angle) relative to the flow path wall 201, or the first heat dissipation unit 305a and the second heat dissipation unit 305b, the force acting in the direction of the extraction from the flow path forming body 200 can be reduced.
In the flow path forming body 200, a second opening 402 different from the first opening 401 may be formed. At this time, the second opening 402 is formed on the surface of the flow path forming body 200 different from the first opening 401, and the second opening 402 is formed to communicate one surface of the flow path forming body 200 with the flow path 400.
The flow path forming body 200 having the second opening 402 different from the first opening 401 contains the power semiconductor module 300g in which the first terminal 320 is projected from the first opening 401 and the second terminal 321 is projected from the second opening 402 and forms the flow path 400 through which the refrigerant flows. The principle illustrated in
Number | Date | Country | Kind |
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2016-090042 | Apr 2016 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2017/008301 | 3/2/2017 | WO | 00 |