JP5380834B2 - DC-AC converter - Google Patents

Description

  The present invention relates to a DC / AC converter used in an electric vehicle or the like, and more particularly to an arrangement structure thereof.

  4A and 4B are a front view and a circuit diagram of the conventional DC-AC converter shown in Patent Document 1, in which the semiconductor module 1 and the first smoothing capacitor groups 2 and 3 are on the negative side. The conductor 4 and the positive conductor 5 are connected, and the semiconductor module 1 and the second smoothing capacitor groups 6 and 7 are connected by the negative conductor 8 and the positive conductor 5. The negative conductor 4 has a planar structure, the positive conductor 5 has an inverted T shape, and the negative conductor 8 has an L shape. Further, the second smoothing capacitor groups 6 and 7 are arranged above the first smoothing capacitor groups 2 and 3, and the conductors 4, 5 and 8 are arranged close to each other, and an insulating material is sandwiched therebetween. Further, one end of each of the negative side conductors 4 and 8 is fastened to a terminal of the semiconductor module 1 with a male screw 9 so as to have the same potential. The semiconductor module 1 includes a plurality of pairs of upper and lower arm semiconductor switching elements 10 and 11 and diodes 12 and 13 connected in antiparallel thereto. L1 to L5 are inductances of the conductors 4, 5, and 8, respectively.

  5A and 5B show a front view and a circuit diagram of the conventional DC-AC converter shown in Patent Document 2, and first, as shown in FIG. Between the side DC conductor 15, semiconductor modules 16 U, 16 V, and 16 W of U, V, and W phases are connected in parallel via power supply terminals 17 and 18, and terminals are connected between the DC conductors 14 and 15. A capacitor 19 is connected in parallel with each of the semiconductor modules 16U, 16V, and 16W via 19a and 19b. The control terminals 20 to 23 of the semiconductor modules 16U, 16V, and 16W are connected to the control circuit unit 24. The control circuit unit 24 controls on / off of each switching element by turning on / off the base current of each switching element, and the motor from the output terminal 25 of each semiconductor module 16U, 16V, 16W via the output conductors 26U, 26V, 26W. Outputs three-phase AC power to the output terminal.

In this DC-AC converter, the semiconductor modules 16U, 16V, and 16W are arranged in a line on a mounting surface 27a of a cooling block 27 made of aluminum as shown in FIG. Power supply terminals 17, 18, control terminals 20 to 23 and an output terminal 25 are provided on the upper surface of each semiconductor module 16 U, 16 V, 16 W, and a positive input conductor 14 is attached on the power supply terminal 17. Is attached with a negative input conductor 15, and output conductors 26 U, 26 V, and 26 W are attached on the output terminal 25. A holder 28 made of an aluminum block is provided on the mounting surface 27a of the cooling block 27, and the holder 28 supports the bottom of the capacitor 19 above the semiconductor modules 16U, 16V, and 16W. That is, a capacitor accommodation hole 28 a is provided in the upper part of the holder 28 in the horizontal direction, and the bottom of the capacitor 19 is inserted into the capacitor accommodation hole 28 a and is fixed by the presser fitting 29 and the screw 30. Terminals 19 a and 19 b of a capacitor 19 are connected to the input conductors 14 and 15 via connection conductors 31 and 32.
JP 2005-65412 A JP-A-7-298641

  Conventional DC-AC converters generally have electrolytic capacitors 2, 3, 6, and 7 arranged on the lateral side of the semiconductor module 1, as shown in Patent Document 1 in FIG. However, in such an arrangement structure, the occupied area viewed from above increases, and the occupied area of the DC-AC converter increases. Further, since the electrolytic capacitors 2, 3, 6, and 7 are arranged on the lateral side of the semiconductor module 1, the length of the connecting conductor from the terminal of the semiconductor module 1 to the terminals of the electrolytic capacitors 2, 3, 6, and 7 Becomes relatively long, the stray inductance component increases, and the surge voltage during switching of the semiconductor module 1 increases. Therefore, in order to reduce the area occupied by the DC-AC converter and reduce the length of the connection conductor from the terminal of the semiconductor module to the terminal of the electrolytic capacitor, as shown in Patent Document 2 of FIG. , 16V, and 16W have been proposed in which an electrolytic capacitor 19 is provided. However, what is disclosed in Patent Document 2 is effective when the semiconductor modules 16U, 16V, and 16W are used in a single phase for the output side, but the semiconductor modules 16U, 16V, and 16W have insufficient capacity. Therefore, when using each phase parallel to the output side, the lengths of the conductors from the electrolytic capacitor 19 to the semiconductor modules 16U, 16V, and 16W are unbalanced. Note that the capacity was particularly insufficient when the semiconductor module was formed of IGBT.

  The present invention has been made to solve the above-described problems. Even when a semiconductor module is used in parallel with each phase with respect to the output side, the occupied area is reduced and the semiconductor module is reduced in size. An object of the present invention is to obtain a DC-AC converter capable of shortening the length of a connection conductor from a module terminal to an electrolytic capacitor terminal.

The DC-AC converter according to claim 1 of the present invention has positive and negative connection electrodes arranged side by side in the same direction on the surface of the casing, and the positions of the connection electrodes of the capacitors are staggered, that is, line symmetrical. Alternatively, a plurality of capacitors arranged in a rotationally symmetrical manner are supported, and each phase of the AC conductor and the AC terminal of each phase semiconductor module, and the connection between the P-side and N-side DC conductor and the DC terminal of each phase semiconductor module are connected. The connection was made on the lower surface of the capacitor support.

According to a second aspect of the present invention , in the DC-AC conversion device according to the first aspect, each of the phase AC conductors is attached to the lower surface of the capacitor support with a male screw.

As described above, according to the first aspect of the present invention, the positive electrode and the negative electrode are arranged adjacent to each other in the same direction on the surface of the housing, and the positions of the connection electrodes of the capacitors are staggered, that is, line symmetrical or A plurality of capacitors arranged and supported in a rotationally symmetrical manner are provided, and the connection between the AC conductor of each phase and the AC terminal of each phase semiconductor module, and the connection between the P side and N side DC conductors and the DC terminal of each phase semiconductor module is a capacitor. Since the connection is made on the lower surface of the support, the component density can be improved, and thereby the circuit impedance can be reduced.

According to claim 2, each phase AC conductor is provided with a female screw portion, and the male screw is screwed into the female screw portion, so that each phase AC conductor can be easily and detachably attached to the lower surface of the capacitor support. it can.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 is an exploded perspective view of a DC-AC converter without an electrolytic capacitor according to an embodiment of the present invention, FIG. 2 is a perspective view of the DC-AC converter, and FIG. 3 is a circuit diagram of the DC-AC converter. is there. In the circuit diagram of FIG. 3, reference numerals 33 and 34 denote P-side and N-side DC conductors connected to a DC power source, and four electrolytic capacitors 35 to 38 are arranged in parallel between the DC conductors 33 and 34. In addition to being connected, the respective phase semiconductor modules U1, U2, V1, V2, W1, W2 are connected in parallel. Each phase semiconductor module U1, U2, V1, V2, W1, W2 is composed of upper and lower arm IGBTs 39, 40 and diodes 41, 42 connected in antiparallel thereto, and each of these phase semiconductor modules U1, U2, A DC-AC conversion circuit is configured by bridge-connecting V1, V2, W1, and W2. The connection points of the upper and lower arms of each phase semiconductor module U1, U2, V1, V2, W1, W2, that is, the AC output terminals are connected in parallel to the AC conductors U3, V3, W3 of each phase for each phase. It is connected to the motor 43 via U3, V3 and W3.

  Next, the arrangement structure of the DC-AC converter described above will be described. The semiconductor modules U1, U2, V1, V2, W1, and W2 are mounted on the printed board 44, and the P-side DC conductor 33 and the N-side are provided on the upper surfaces of the semiconductor modules U1, U2, V1, V2, W1, and W2. The DC conductor 34 is attached so that the semiconductor modules U1, U2, V1, V2, W1, and W2 are connected in parallel between the DC conductors 33 and 34. Further, the DC conductors 33 and 34 are insulated by an insulating plate 45. Also, each DC conductor 33, 34 is provided with four upright connection portions 33a, 34a alternately and integrally at both ends in accordance with the positions of the connection electrodes of the electrolytic capacitors 35-38. On the surface of the casing of each electrolytic capacitor 35 to 38, a positive electrode and a negative electrode are arranged side by side and arranged in the same direction. An electrolytic capacitor support 47 made of resin is attached above each semiconductor module U1, U2, V1, V2, W1, W2 by screwing a male screw 48 to a female screw portion 44a of the printed board 44. Electrolytic capacitors 35 to 38 having + and − connection electrodes at one end are arranged alternately in the four recesses 47a of the support 47, that is, the positions of the connection electrodes are arranged in line symmetry or rotational symmetry, Connected to the connecting portions 33a and 34a. Each electrolytic capacitor 35 to 38 is restrained by a support band 49 attached to the electrolytic capacitor support 47 by two.

  Further, P-phase, V-phase, and W-phase AC conductors U3, V3, and W3 are attached to the insulating plate 45 on each phase semiconductor module U1, U2, V1, V2, W1, and W2, and each AC conductor U3, V3 and W3 are connected to the connection points of the upper and lower arms of the semiconductor modules U1, U2, V1, V2, W1, and W2, that is, output points. The AC conductors V3 and W3 of the V phase and the W phase are screwed with male screws 50 through which the electrolytic capacitor support 47 is inserted into the female screw portions V3a and W3a, respectively, so that the AC conductor is supported by the electrolytic capacitor support 47. V3 and W3 are supported.

  In the above-described best mode, when the semiconductor modules U1, U2, V1, V2, W1, and W2 including the IGBTs 39 and 40 are connected in parallel to the AC conductors U3, V3, and W3, The electrolytic capacitors 35 to 38 are arranged above the semiconductor modules U1, U2, V1, V2, W1, and W2, so that the area occupied by the DC-AC converter can be reduced, and the DC-AC converter can be reduced in size. Can be. In addition, the electrolytic capacitors 35 to 38 having connection electrodes at one end are arranged so that the positions of the connection electrodes are staggered, and the connection electrodes of the electrolytic capacitors 35 to 38 are connected to the electrolytic capacitors 35 to 38. Since they are alternately located at both ends, the connecting portions 33a, 34a of the DC conductors 33, 34 are also alternately located, and the DC conductors 33, 34 are on the respective phase semiconductor modules U1, U2, V1, V2, W1, W2. Each phase semiconductor module U1, U2, V1, V2, W1, W2 is attached and connected in parallel, and each capacitor 35-38 in which the positions of the connection electrodes are staggered is connected in parallel, and each semiconductor module U1 , U2, V1, V2, W1, W2 to the connection electrodes from the DC electrodes to the connection electrodes of the electrolytic capacitors 35-38, that is, the lengths of the DC conductors 33, 34 are made equal. Kusuru it possible, by reducing the stray inductance components, the switching surge voltage of the semiconductor module U1, U2, V1, V2, W1, W2 can be reduced. In addition, an electrolytic capacitor support 47 is provided above each semiconductor module U1, U2, V1, V2, W1, W2 to arrange the electrolytic capacitors 35 to 38, and the electrolytic capacitor support 47 provides the V phase and W phase. AC capacitor V3 and W3 are also supported, and electrolytic capacitor support 47 is used both for supporting electrolytic capacitors 35 to 38 and for supporting AC conductors V3 and W3, thereby reducing circuit impedance by improving component density. Thus, the surge voltage can be further reduced.

It is a disassembled perspective view of the orthogonal transformation device which omitted illustration of the electrolytic capacitor by this embodiment of the invention. It is a perspective view of the orthogonal transformation device by an embodiment. 1 is a circuit diagram of an orthogonal transform device according to an embodiment. It is the front view and circuit diagram of the conventional orthogonal transformation apparatus shown by patent document 1. FIG. It is the front view and circuit diagram of the conventional orthogonal transformation apparatus shown by patent document 2. FIG.

Explanation of symbols

33 ... P-side DC conductor 33a, 34a ... Connection 34 ... N-side DC conductor 35-38 ... Electrolytic capacitor 43 ... Motor 44 ... Printed board 44a, V3a, W3a ... Female thread 45 ... Insulating plate 47 ... Capacitor support U1, U2, V1, V2, W1, W2 ... Semiconductor module U3, V3, W3 ... AC conductor

Claims (2)

There are positive and negative connection electrodes arranged next to each other in the same direction on the surface of the housing , and each capacitor has a plurality of capacitors that are supported by arranging the positions of the connection electrodes alternately, that is, in line symmetry or rotational symmetry. The DC conductor is characterized in that the connection between the AC conductor of each phase and the AC terminal of each phase semiconductor module, and the connection between the P-side and N-side DC conductors and the DC terminal of each phase semiconductor module is connected on the lower surface of the capacitor support. AC converter.   2. The DC-AC converter according to claim 1, wherein each phase AC conductor is attached to the lower surface of the capacitor support by a male screw.

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