JP6134798B2 - Power converter - Google Patents

Description

The present invention relates to a power conversion device, and more particularly to a power conversion device suitable for application of a self-extinguishing semiconductor element such as an IGBT (insulated gate bipolar transistor).

  In recent years, in the field of power control, power converters (inverter devices) that convert direct current to alternating current / alternating current to direct current have come to be used. Among these inverter devices, for example, a three-level inverter device is given as a typical circuit of a large capacity inverter device. The three-level inverter device is a DC voltage circuit having three potentials, that is, a positive potential P, a negative potential N, and an intermediate potential C, and three levels that can output the positive potential P, the negative potential N, and the intermediate potential C. An inverter device having an inverter bridge.

  As the self-extinguishing type semiconductor element applied to construct a large capacity inverter device, for example, a so-called current driven type element such as a GTO (gate turn-off thyristor) has been mainly used. Increasing the capacity of certain IGBTs (Insulated Gate Bipolar Transistors) and IEGTs (Injection-Promoting Gate Transistors) has been applied.

  Large-capacity IGBTs (Insulated Gate Bipolar Transistors) and IEGTs (Injection-Promoting Gate Transistors) have many so-called multichip configurations in which multiple semiconductor chips are connected in parallel inside the package as a feature of voltage-driven elements. Adopted. As this package, a pressure contact type in which semiconductor chips are arranged in a flat metal container and pressure is applied from both sides to realize a uniform parallel circuit has been put into practical use.

In the self-extinguishing semiconductor element used in the inverter device, a flywheel diode is connected in antiparallel to the self-extinguishing semiconductor element in order to secure a return path for an inductive load or the like. This flywheel diode is often housed in a package together with a self-extinguishing semiconductor chip to form a composite element. That is, a flywheel diode chip and a self-extinguishing semiconductor chip are arranged in a flat metal container inside the above-described package. Such a technique is described in Patent Document 1, for example.

JP 2001-78467 A JP 2006-158107 A

  In the above prior art, a flywheel diode chip is housed in a single package together with a self-extinguishing semiconductor chip to form a composite element. Generally, a chip structure is a mesa structure in a self-extinguishing semiconductor chip such as an IGBT. In addition, since the chip structure of the diode is a flat structure, a pressure difference is generated between the chip surface and the electrode even if the diameter of the electrode to be pressed is the same.

  On the other hand, an element in which a flywheel diode is housed in a separate package has been put into practical use. Such a technique is described in Patent Document 2, for example. In this technology, an inverter device is configured using a self-extinguishing semiconductor element and a flywheel diode element housed in a package, but the clamp diode and the self-extinguishing semiconductor element are arranged in series. Generally, the number of diode chips in the semiconductor package to be in pressure contact is different from the number of chips in the self-extinguishing semiconductor element, and the diameter of these pressure contact structures cannot be reduced to the minimum necessary diameter. In addition, there arises a problem that enlargement is inevitable. In addition, when the semiconductor package is configured with different diameters, the surface pressure of the large-diameter semiconductor package is reduced with respect to the small-diameter semiconductor package, and the contact thermal resistance is increased on the side formed with the large-diameter semiconductor package There arises a problem of current concentration.

The present invention has been made in view of the above, and an object of the present invention is to provide a power converter that can be reduced in size and can suppress contact thermal resistance and current concentration.

In order to achieve the above object, in the present invention, a first semiconductor element, a second semiconductor element, a third semiconductor element, and a fourth semiconductor element connected in series between one terminal and the other terminal; , A first flywheel diode, a second flywheel diode, a third flywheel diode provided corresponding to each of the first semiconductor element, the second semiconductor element, the third semiconductor element, and the fourth semiconductor element, A flywheel diode and a fourth flywheel diode, a connection portion between the first semiconductor element and the second semiconductor element, and an intermediate potential terminal which is a potential between the one side terminal and the other side terminal. A first clamp diode to be connected; and a second clamp diode for connecting a connection portion between the third semiconductor element and the fourth semiconductor element and the intermediate potential terminal; Body element, the second semiconductor device, the third semiconductor element and the fourth semiconductor element is composed of a first semiconductor package of each substantially the same diameter, are connected by insulation displacement connection due to the series arrangement, the The first flywheel diode, the second flywheel diode, the first clamp diode, the second clamp diode, the third flywheel diode, and the fourth flywheel diode each have substantially the same diameter. And the first semiconductor package and the second semiconductor package having a different diameter, and are arranged in series so that the first flywheel diode and the second flywheel diode are connected by pressure contact, The first clamp diode and the second clamp diode are connected by pressure contact, and the third clamp diode Flywheel diode and the fourth flywheel diode was configured to be connected by welding.

According to the present invention, miniaturization is possible, and contact thermal resistance and current concentration can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a circuit diagram of the inverter apparatus which concerns on Example 1 of this invention, and the structure figure for 1 phase of inverter bridges. It is explanatory drawing for showing the effect of the inverter apparatus which concerns on Example 1 of this invention. It is a circuit diagram of an inverter device and a structural diagram for one phase of an inverter bridge. It is an electric current route explanatory view (ac) for one phase of an inverter bridge concerning the present invention. It is current path explanatory drawing (df) for 1 phase of inverter bridges concerning the present invention. It is a structural diagram for one phase of the inverter bridge in the case of a two-parallel configuration. It is current path explanatory drawing (ac) for 1 phase of inverter bridges when it is set as 2 parallel configuration. It is current path explanatory drawing (df) for the inverter bridge 1 phase at the time of setting it as 2 parallel structure.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a power conversion apparatus according to Embodiment 1 of the present invention. FIG. 1 (a) shows a circuit configuration of the inverter device of the present invention, and FIG. 1 (b) simply shows a structural diagram of one phase of the inverter bridge of the inverter device according to the present invention. . 1A and 1B show a circuit configuration and a structure only for one phase of the inverter for simplicity. For example, in the case of converting DC to three-phase AC, a self-extinguishing type in which flywheel diodes 6, 7, 8 and 9 are connected in reverse parallel between a positive potential P and a negative potential N, respectively. In addition to the illustrated set of series circuits of semiconductor elements 2, 3, 4 and 5, two sets are connected, and an intermediate potential C and self-extinguishing semiconductor elements 2, 3, 4 and 5 are connected. Two sets of clamp diodes 10 and 11 are connected in the same manner.

  In FIG. 1A, a DC voltage circuit 1 has a positive potential P, a negative potential N, and an intermediate potential C, and a series of self-extinguishing semiconductor elements 2, 3, 4 and 5 in parallel with the DC voltage circuit 1. The circuit is connected. Further, flywheel diodes 6, 7, 8, and 9 are connected in antiparallel to the self-extinguishing semiconductor elements 2, 3, 4, and 5, respectively. The clamp diode 10 is connected in a direction in which a current flows from the terminal of the potential C of the DC voltage circuit 1 toward the connection point of the self-extinguishing semiconductor elements 2 and 3 connected in series, and the clamp diode 11 is connected in series The self-extinguishing semiconductor elements 4 and 5 are connected in a direction in which a current flows from the connection point of the self-extinguishing semiconductor elements 4 and 5 toward the terminal of the potential C of the DC voltage circuit 1. OUT is an output terminal connected to a load (not shown).

  Here, the self-extinguishing semiconductor elements 2, 3, 4 and 5 are each formed of a semiconductor package. This semiconductor package is configured by arranging semiconductor chips (IGBT chips) in a flat metal container, and a uniform connection circuit is realized by applying pressure from both sides. Similarly, the flywheel diodes 6, 7, 8, and 9 and the clamp diodes 10 and 11 are configured by arranging diode chips in a flat metal container, and two predetermined circuits are applied by applying pressure from both sides. Are designed to realize a uniform connection circuit.

  Next, in FIG. 1B, the first pressure contact structure 12 is formed by stacking six semiconductor packages of flywheel diodes 6, 7, 8, and 9 and clamp diodes 10 and 11, and each semiconductor package. Each of the cooling fins 13, 14, 15, 16, 17, 18, 19, 20, and 21 and the insulators 22 and 23 that are interposed between the insulators 22 and 23 is a skewer structure.

  The second press-contact structure 24 includes a self-extinguishing type semiconductor element 2, 3, 4 and 5 and a skewer in which cooling fins 25, 26, 27, 28 and 29 provided between them are fastened together. It has a mold structure.

  The wiring 30 is a bus bar that electrically connects the cooling fins 16 attached to the cathode side of the clamp diode 10 and the cooling fins 14 attached to the cathode side of the flywheel diode 7. Similarly, the wiring 31 is a bus bar that electrically connects the cooling fin 18 attached to the anode side of the clamp diode 11 and the cooling fin 20 attached to the anode side of the flywheel diode 8. The wiring 32 is a bus bar that electrically connects the cooling fin 15 attached to the anode side of the flywheel diode 7 and the cooling fin 19 attached to the cathode side of the flywheel diode 8.

  Wirings 33, 34, 35, 36, and 37 are connection wirings between the self-extinguishing semiconductor element and the flywheel diode, and the wiring 33 is connected to the cooling fin 25 attached to the collector side of the self-extinguishing semiconductor element 2 and the flywheel diode. The cooling fin 13 attached to the cathode side of the wheel diode 6 and the wiring 34 are the cooling fin 26 attached to the collector side of the self-extinguishing semiconductor element 3 and the cooling fin 14 attached to the cathode side of the flywheel diode 7. The wiring 35 is the cooling fin 27 attached to the collector side of the wiring 32 and the self-extinguishing semiconductor element 4, and the wiring 36 is the cooling fin 28 attached to the collector side of the self-extinguishing semiconductor element 5 and the flywheel diode 9. The cooling fin 20 attached to the cathode side and the wiring 37 are the cooling fin 29 attached to the emitter side of the self-extinguishing semiconductor element 5 and the flywheel diode 9 And cooling fins 21 attached to the anode side is a bus bar to electrically connected respectively. Note that the corresponding portions of the wirings 30 to 37 are shown in FIG.

  Here, the first pressure contact structure 12 is composed only of a diode, and the second pressure contact structure 24 is composed only of a self-extinguishing semiconductor element. For example, in the first pressure contact structure 12, the electrical connection of the flywheel diodes 6 and 7 constituting the first pressure contact structure 12 is ensured by pressing the cooling fins 13 and the cooling fins 21 from the outside, respectively. The electrical connection of the clamp diodes 10 and 11 is secured, and the electrical connection of the flywheel diodes 8 and 9 is secured. Similarly, in the second press-contact structure 24, the self-extinguishing semiconductor elements 2, 3, 4 and 5 constituting the second press-contact structure 24 by pressing the cooling fin 25 and the cooling fin 29 from the outside respectively. Ensure each electrical connection.

  With this configuration, even when the number of diode chips and the number of self-extinguishing semiconductor elements in the semiconductor package to be pressed are different, the diameters of the first pressure contact structure and the second pressure contact structure are reduced. The diameter can be reduced to the minimum necessary, and the size can be reduced. For example, if the allowable current per chip of the diode is 100 A and the allowable current per chip of the self-extinguishing semiconductor element is 50 A, the number of chips required for the diode semiconductor package is the self-extinguishing semiconductor element. Half of it is good. Accordingly, since the area perpendicular to the pressure contact surface of the semiconductor package of the diode may be half that of the self-extinguishing semiconductor element, the size of the inverter can be reduced as shown in FIG. At this time, in the pressure contact structure constituted by semiconductor packages having different diameters, the contact pressure of the diode constituted by the semiconductor package having a large diameter decreases due to a decrease in the surface pressure of the semiconductor package having a large diameter relative to the semiconductor package having a small diameter. This leads to an increase in resistance and current concentration. Therefore, the semiconductor package constituting the pressure contact structure must have the same diameter.

  The block diagram of the power converter device which concerns on FIG. 3 at Example 2 is shown. FIG. 3 (a) shows the circuit configuration of the inverter device of the present invention, and FIG. 3 (b) simply shows the structural diagram of one phase of the inverter bridge of the inverter device according to the present invention. . 3A and 3B show a circuit configuration and a structure only for one phase of the inverter for simplicity.

  In FIG. 3A, the DC voltage circuit 38 has a positive potential P, a negative potential N, and an intermediate potential C, and flywheel diodes 39, 40, 41, and 42 are connected in reverse parallel to the DC voltage circuit 38. Yes. In addition, series circuits of self-extinguishing semiconductor elements 43, 44, 45 and 46 are connected to the flywheel diodes 39, 40, 41 and 42, respectively. Further, self-extinguishing semiconductor elements 47, 48, 49 and 50 are connected in parallel to the self-extinguishing semiconductor elements 43, 44, 45 and 46. The clamp diode 51 is connected in a direction in which a current flows from the terminal of the potential C of the DC voltage circuit 38 toward the connection point of the flywheel diodes 39 and 40, and the clamp diode 52 is connected to the flywheel diode connected thereto. They are connected in a direction in which current flows from the connection point of 41 and 42 toward the terminal of the potential C of the DC voltage circuit 38. OUT is an output terminal connected to a load (not shown). Next, in FIG. 3B, the first pressure contact structure 53 is configured by stacking six semiconductor packages of flywheel diodes 39, 40, 41 and 42 and clamp diodes 51 and 52, and each semiconductor package. The cooling fins 54, 55, 56, 57, 58, 59, 60, 61, and 62, and the insulators 63 and 64, which are interposed between the two, are skewered.

  The second press-contact structure 65 includes a self-extinguishing type semiconductor element 43, 44, 45 and 46 and a skewer in which cooling fins 66, 67, 68, 69 and 70 provided between them are fastened together. It has a mold structure.

  Further, the third press-contact structure 71 includes a skewer in which self-extinguishing semiconductor elements 47, 48, 49, and 50 and cooling fins 72, 73, 74, 75, and 76 provided therebetween are fastened together. It has a mold structure.

  The wiring 77 is a bus bar that electrically connects the cooling fin 57 attached to the cathode side of the clamp diode 51 and the cooling fin 55 attached to the cathode side of the flywheel diode 40. Similarly, the wiring 78 is a bus bar that electrically connects the cooling fin 59 attached to the anode side of the clamp diode 52 and the cooling fin 61 attached to the anode side of the flywheel diode 41. The wiring 79 is a bus bar that electrically connects the cooling fin 56 attached to the anode side of the flywheel diode 40 and the cooling fin 60 attached to the cathode side of the flywheel diode 41.

  Wirings 80, 81, 82, 83, and 84 are transition wirings between the self-extinguishing semiconductor element and the flywheel diode, and the wiring 80 is connected to the cooling fin 66 attached to the collector side of the self-extinguishing semiconductor element 43 and the flywheel diode. The cooling fin 54 attached to the cathode side of the wheel diode 39, the wiring 81 is a cooling fin 67 attached to the collector side of the self-extinguishing semiconductor element 44, and the cooling fin 55 attached to the cathode side of the flywheel diode 40, The wiring 82 is the cooling fin 68 attached to the collector side of the wiring 79 and the self-extinguishing semiconductor element 45, and the wiring 83 is the cooling fin 69 attached to the collector side of the self-extinguishing semiconductor element 46 and the flywheel diode 42. The cooling fin 61 and wiring 84 attached to the cathode side are connected to the cooling fin 70 and flywheel diode attached to the emitter side of the self-extinguishing semiconductor element 46. A bus bar for connecting the cooling fins 62 attached to the anode side of the de 42 respectively electrically.

  The wirings 85, 86, 87, 88 and 89 are connected between the self-extinguishing semiconductor element constituting the second pressure contact structure 65 and the self-extinguishing semiconductor element constituting the third pressure contact structure 71. Wiring 85 is a cooling fin 66 attached to the collector side of self-extinguishing semiconductor element 43, cooling fin 72 attached to the collector side of self-extinguishing semiconductor element 47, and wiring 86 is self-extinguishing. The cooling fin 67 attached to the collector side of the type semiconductor element 44, the cooling fin 73 attached to the collector side of the self-extinguishing type semiconductor element 48, and the wiring 87 were attached to the collector side of the self-extinguishing type semiconductor element 45. The cooling fins 68 and the cooling fins 74 attached to the collector side of the self-extinguishing semiconductor element 49 and the wiring 88 are the cooling fins 69 and the self-extinguishing semiconductor element 50 attached to the collector side of the self-extinguishing semiconductor element 46. Mounted on the collector side of Rejection fin 75 and wiring 89 electrically connect cooling fin 70 attached to the emitter side of self-extinguishing semiconductor element 46 and cooling fin 76 attached to the emitter side of self-extinguishing semiconductor element 50, respectively. Busbar. Incidentally, the corresponding portions of the wirings 77 to 89 are shown in FIG.

Here, the first pressure contact structure 53 is composed of only a diode, and the second pressure contact structure 65 and the third pressure contact structure 71 are composed of only a self-extinguishing semiconductor element. With such a configuration, the parallel self-extinguishing semiconductor elements are located in the vicinity without many BUSs and capacitors, so the current flow is imbalanced due to variations in circuit inductance. Further, it is possible to suppress the generation of heat due to current concentration and the damage of the semiconductor chip due to the surge voltage. Furthermore, since the capacity density per unit (VA / m ³ ) can be increased and only one press-contact structure is added, the entire apparatus is not enlarged, and the capacity density (VA) of the entire apparatus is reduced. / m ³ ) can be increased.

  In the following, the proposed structure shown in FIG. 3 reduces the variation in the inductance of the circuit and reduces the current unintentional than connecting the third pressure contact structure composed only of the self-extinguishing semiconductor element in parallel. The reason why the balance can be suppressed will be described with reference to FIGS. 4-1, 4-2, 5, 6-1 and 6-2.

  First, current paths that flow during inverter operation in the structure of the present invention shown in FIGS. 4-1 and 4-2 are shown. There are six current paths in total, a path flowing from the positive potential P shown in FIG. 4A to the output terminal OUT through the self-extinguishing semiconductor element, and an intermediate potential C shown in FIG. To the clamp diode, the path flowing through the self-extinguishing semiconductor element to the output terminal OUT, the path flowing from the negative potential N shown in FIG. 4-1 (c) to the output terminal OUT through the flywheel diode, FIG. ) From the output terminal OUT to the negative potential P through the flywheel diode, the path from the output terminal OUT to the intermediate potential C through the self-extinguishing semiconductor element and the clamp diode shown in FIG. FIG. 4B is a path that flows from the output terminal OUT to the negative potential N through the self-extinguishing semiconductor element.

  In FIG. 4A, the path flowing from the positive potential P through the self-extinguishing semiconductor elements 43 and 44 to the output terminal OUT and the positive potential P through the self-extinguishing semiconductor elements 47 and 48 to the output terminal OUT. The lengths of the flow paths are equal, and imbalance due to the wiring of the current passing through the first parallel and the second parallel is unlikely to occur.

  In FIG. 4B, the clamp diode 51 from the intermediate potential C passes through the self-extinguishing semiconductor element 44 to the output terminal OUT and the clamp diode 51 from the intermediate potential C to the self-extinguishing semiconductor. The length of the path that passes through the element 48 and flows to the output terminal OUT is equal, and an imbalance due to current wiring passing through the first and second parallels is unlikely to occur.

  Further, in FIG. 4E, a path that flows from the output terminal OUT through the self-extinguishing semiconductor element 45 and the clamp diode 52 to the intermediate potential C and the self-extinguishing semiconductor element 49 and clamp diode from the output terminal OUT. The length of the path that passes through 52 and flows to the intermediate potential C is equal, and imbalance due to the wiring of the current passing through the first parallel and the second parallel is unlikely to occur.

  In FIG. 4-2 (f), the path flowing from the output terminal OUT through the self-extinguishing semiconductor elements 45 and 46 to the negative potential N and the output terminal OUT passing through the self-extinguishing semiconductor elements 49 and 50 and the negative potential. The length of the path flowing through N is equal, and imbalance due to the wiring of the current passing through the first parallel and the second parallel is unlikely to occur.

  In FIG. 4C, since the common flywheel diodes 41 and 42 pass, there is only one path and no current imbalance can occur. Similarly in FIG. 4D, since the current passes through the common flywheel diodes 39 and 40, there is only one path and no current imbalance occurs.

  Next, FIG. 5 shows a configuration diagram in which the third pressure contact structure is connected.

  In FIG. 5, a series circuit of self-extinguishing semiconductor elements 90, 91, 92 and 93 is connected in parallel to a positive potential P and a negative potential N. Further, flywheel diodes 94, 95, 96 and 97 are connected in reverse parallel to the self-extinguishing semiconductor elements 90, 91, 92 and 93, respectively. Further, self-extinguishing semiconductor elements 98, 99, 100 and 101 are connected in parallel to the flywheel diodes 94, 95, 96 and 97. The clamp diode 102 is connected in a direction in which a current flows from the terminal of the potential C toward the connection point of the self-extinguishing semiconductor elements 90 and 91 connected in series, and the clamp diode 103 is connected in series. They are connected in a direction in which current flows from the connection point of the type semiconductor elements 92 and 93 toward the terminal of the potential C. OUT is an output terminal connected to a load (not shown). Further, the first pressure contact structure 104 is formed by stacking six semiconductor packages of self-extinguishing semiconductor elements 90, 91, 92, and 93 and clamp diodes 102 and 103, and is interposed between the semiconductor packages. The cooling fins 105, 106, 107, 108, 109, 110, 111, 112, and 113 and the insulators 114 and 115 are clamped together.

  The second press-contact structure 116 has a skewer structure in which flywheel diodes 94, 95, 96, and 97 and cooling fins 117, 118, 119, 120, and 121 provided between them are fastened together. It has become.

  Further, the third pressure contact structure 122 includes a self-extinguishing semiconductor element 98, 99, 100 and 101 and a skewer in which cooling fins 123, 124, 125, 126 and 127 provided therebetween are fastened together. It has a mold structure.

    The wiring 128 is a bus bar that electrically connects the cooling fin 108 attached to the cathode side of the clamp diode 102 and the cooling fin 106 attached to the emitter side of the self-extinguishing semiconductor element 90. Similarly, the wiring 129 is a bus bar that electrically connects the cooling fin 110 attached to the anode side of the clamp diode 103 and the cooling fin 112 attached to the emitter side of the self-extinguishing semiconductor element 92. The wiring 130 is a bus bar that electrically connects the cooling fin 107 attached to the emitter side of the self-extinguishing semiconductor element 91 and the cooling fin 111 attached to the collector side of the self-extinguishing semiconductor element 92. .

  Wirings 131, 132, 133, 134, and 135 are transition wirings between the self-extinguishing semiconductor element and the flywheel diode, and the wiring 131 is connected to the cooling fin 105 attached to the collector side of the self-extinguishing semiconductor element 90 and the flywheel diode. The cooling fin 117 attached to the cathode side of the wheel diode 94, the wiring 132 includes the cooling fin 106 attached to the collector side of the self-extinguishing semiconductor element 91 and the cooling fin 118 attached to the cathode side of the flywheel diode 95, The wiring 133 is the cooling fin 119 attached to the cathode side of the wiring 130 and the flywheel diode 96, and the wiring 134 is the cooling fin 112 attached to the collector side of the self-extinguishing semiconductor element 93 and the cathode side of the flywheel diode 97. The attached cooling fin 120 and wiring 135 are connected to the cooling fin 113 attached to the emitter side of the self-extinguishing semiconductor element 93 and the frame. The bus bar electrically connects the cooling fins 121 attached to the anode side of the i-wheel diode 97.

  The wirings 136, 137, 138, 139, and 140 are connected between the self-extinguishing semiconductor element constituting the second pressure contact structure 116 and the self-extinguishing semiconductor element constituting the third pressure contact structure 122. The wiring 136 is a cooling fin 117 attached to the cathode side of the flywheel diode 94 and the cooling fin 123 attached to the collector side of the self-extinguishing semiconductor element 98, and the wiring 137 is the cathode of the flywheel diode 95. The cooling fin 118 attached to the side, the cooling fin 124 attached to the collector side of the self-extinguishing semiconductor element 99, and the wiring 138 are the cooling fin 119 attached to the cathode side of the flywheel diode 96 and the self-extinguishing semiconductor The cooling fin 125 attached to the collector side of the element 100 and the wiring 139 are the cooling fin 120 attached to the cathode side of the flywheel diode 97 and the self-extinguishing semiconductor element 101. The cooling fin 126 and the wiring 140 attached to the collector side are electrically connected to the cooling fin 121 attached to the anode side of the flywheel diode 97 and the cooling fin 127 attached to the emitter side of the self-extinguishing semiconductor element 101, respectively. It is a bus bar to connect to.

  FIGS. 6A and 6B show current paths that flow during inverter operation in the configuration in which the third press-contact structure is connected. There are 6 current paths in total, and the path from the positive potential P shown in FIG. 6-1 (a) through the self-extinguishing semiconductor element to the output terminal OUT is similar to the description of FIGS. 4-1 and 4-2. 6-1 (b), an intermediate potential C shown in FIG. 6-1 (c), a clamp diode, a path flowing through the self-extinguishing semiconductor element to the output terminal OUT, and a negative potential N shown in FIG. 6-1 (c). A path that flows to the output terminal OUT, a path that flows from the output terminal OUT to the negative potential P through the flywheel diode shown in FIG. 6-2 (d), and a self-extinguishing type from the output terminal OUT shown in FIG. 6-2 (e) This is a path that flows to the intermediate potential C through the semiconductor element and the clamp diode, and a path that flows from the output terminal OUT shown in FIG. 6B to the negative potential N through the self-extinguishing semiconductor element.

  In FIG. 6A, the path flowing from the positive potential P through the self-extinguishing semiconductor elements 90 and 91 to the output terminal OUT and the positive potential P through the self-extinguishing semiconductor elements 98 and 99 to the output terminal OUT. The lengths of the flowing paths are different, and imbalance occurs due to the wiring of the current passing through the first parallel and the second parallel.

  In FIG. 6B, the clamp diode 102 and the path through the self-extinguishing type semiconductor element 91 from the intermediate potential C to the output terminal OUT and the clamping diode 102 and the self-extinguishing type semiconductor from the intermediate potential C are shown. The length of the path flowing through the element 99 to the output terminal OUT is different, and an imbalance occurs due to the wiring of the current passing through the first parallel and the second parallel.

  In FIG. 6-2 (e), the path flowing from the output terminal OUT to the self-extinguishing semiconductor element 92 and the clamp diode 103 to the intermediate potential C and the self-extinguishing semiconductor element 100 and the clamp diode from the output terminal OUT. The length of the path that passes through 103 and flows to the intermediate potential C is different, and imbalance occurs due to the wiring of the current passing through the first and second parallels.

  Further, in FIG. 6B, the path flowing from the output terminal OUT through the self-extinguishing semiconductor elements 92 and 93 to the negative potential N and the output terminal OUT from the output terminal OUT through the self-extinguishing semiconductor elements 100 and 101 to the negative potential. The length of the path flowing through N is different, and imbalance occurs due to the wiring of the current passing through the first and second parallels.

  In FIG. 6C, since the common flywheel diodes 96 and 97 are passed, there is only one path and current imbalance cannot be generated. Similarly in FIG. 6D, since the current passes through the common flywheel diodes 94 and 95, there is only one path and no current imbalance occurs.

  From the above, variation in inductance due to wiring can be suppressed, and current imbalance through the first and second parallels can be suppressed.

  In the above embodiment, when IGBTs are connected in parallel to increase the capacity, it is avoided that the distance of the wiring passing between the power source and the output is different between the first parallel and the second parallel, and the variation in inductance in each path is reduced. Generation can be suppressed. Further, as compared with the case where a plurality of power conversion device panels are arranged in the horizontal direction, it is possible to reduce the size of the device by avoiding the addition of a coupling reactor for suppressing a cross current and an increase in wiring. In addition, compared to the pressure contact structure and the different diameter electrodes with different contact areas, the pressure fin material is soft, avoiding excessive pressure on the small area electrode side. It can be avoided that both ends of the fin are deformed toward the smaller diameter of the electrode to be pressed and the thermal resistance and contact resistance around the electrode are increased. By adding the same diameter electrode, it is possible to avoid the phenomenon that the distance from the cooling fin surface to the cooling water passage increases, the heat transfer resistance increases, and the cooling capacity decreases.

Because parallel semiconductor elements are located in the vicinity without many buses or capacitors, the current is unbalanced due to variations in circuit inductance, causing heat generation due to cross current and current concentration, and damage to the semiconductor chip due to surge voltage. Can be prevented from occurring. Furthermore, the entire apparatus can be reduced in size. Further, the pressure difference on the contact surface due to the difference in the tip shape and electrode diameter of the pressure contact structure can be reduced.

1, 38 DC voltage circuit
2, 3, 4, 5, 43, 44, 45, 46, 47, 48, 49, 50, 90, 91, 92, 93, 98, 99, 100, 101 Self-extinguishing semiconductor element
6, 7, 8, 9, 39, 40, 41, 42, 94, 95, 96, 97 Flywheel diode
10, 11, 51, 52, 102, 103 Clamp diode
13, 14, 15, 16, 17, 18, 19, 20, 21, 25, 26, 27, 28, 29, 54, 55, 56, 57, 58, 59, 60, 61, 62, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 105, 106, 107, 108, 109, 110, 111, 112, 113, 117, 118, 119, 120, 121, 123, 124, 125, 126, 127 Cooling fin
22, 23, 63, 64, 114, 115 Insulator
12, 53, 104 First pressure contact structure
24, 65, 116 Second pressure contact structure
71, 122 Third pressure contact structure
30, 31, 32, 33, 34, 35, 36, 37, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140 Wiring

Claims (8)

A first semiconductor element, a second semiconductor element, a third semiconductor element, and a fourth semiconductor element connected in series between one side terminal and the other side terminal, and the first semiconductor element and the second semiconductor A first flywheel diode, a second flywheel diode, a third flywheel diode, and a fourth flywheel diode provided corresponding to each of the element, the third semiconductor element, and the fourth semiconductor element; A first clamp diode that connects a connection portion between the first semiconductor element and the second semiconductor element and an intermediate potential terminal that is a potential between the one-side terminal and the other-side terminal; and the third diode A second clamp diode that connects a connection portion between the semiconductor element and the fourth semiconductor element and the intermediate potential terminal, and includes the first semiconductor element, the second semiconductor element, and the second semiconductor element. The semiconductor element and the fourth semiconductor element is constituted by a first semiconductor package of each substantially the same diameter, are connected by insulation displacement connection due to the series arrangement, the first flywheel diode, said second flywheel The diode, the first clamp diode, the second clamp diode, the third flywheel diode, and the fourth flywheel diode each have a substantially the same diameter and a second semiconductor having a different diameter from the first semiconductor package. The first flywheel diode and the second flywheel diode are connected by pressure contact by being configured in a package and arranged in series, and the first clamp diode and the second clamp diode are The third flywheel diode and the fourth block are connected by pressure welding. Lee wheel diode power conversion device, characterized in that it is connected by welding.   2. The first flywheel diode, the second flywheel diode, the first clamp diode, the second clamp diode, the third flywheel diode, and the fourth flywheel diode according to claim 1. Are each configured as a semiconductor package, and the electrode diameter of the semiconductor package that is press-contacted is the same diameter.   2. The fifth semiconductor element, the sixth semiconductor element, the seventh semiconductor element, and the eighth semiconductor element according to claim 1, wherein the fifth semiconductor element, the sixth semiconductor element, and the seventh semiconductor element are included. And the eighth semiconductor element is connected to the first flywheel diode, the second flywheel diode, the third flywheel diode, and the fourth flywheel diode.   4. The first flywheel diode and the second flywheel diode, the third flywheel diode and the fourth flywheel diode according to claim 3, wherein the first flywheel diode and the second flywheel diode are the first clamp diode and the second flywheel diode. A power converter having a structure in which a clamp diode is sandwiched.   5. The fourth flywheel diode and the first clamp diode are adjacent to each other via an insulating member, and the second clamp diode and the third flywheel diode are adjacent to each other via an insulating member. The power converter characterized by the above-mentioned. 6. The device according to claim 5, wherein the first clamp diode is connected to the first semiconductor element and the second via a conductor provided between the first flywheel diode and the second flywheel diode. is connected to the connection portion of the semiconductor element, the second clamp diodes, through conductors provided between the third flywheel diode and the fourth flywheel diode, the third A power conversion device connected to a connection portion between a semiconductor element and the fourth semiconductor element . 2. The power converter according to claim 1, comprising a DC voltage circuit having three terminals of a positive potential, a negative potential, and an intermediate potential, and a three-level inverter bridge capable of outputting each potential. One phase of the inverter bridge includes the first to fourth semiconductor elements as the first parallel, the first to fourth flywheel diodes and the first to second clamp diodes as the second parallel. The power conversion device is configured such that the wiring inductance passing through the first parallel and the wiring inductance passing through the second parallel are substantially equal.   2. The power converter according to claim 1, wherein a series pressure contact structure constituted by the first to fourth semiconductor elements and a smoothing capacitor are connected in parallel.

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