JP6545117B2 - Power converter - Google Patents

Description

  The present invention relates to a power converter.

  Generally, it is known to connect a plurality of unit capacitors of small capacity in series and in parallel to use as a smoothing capacitor of an inverter. Moreover, in order to prevent explosion of a capacitor, providing a fuse is disclosed (refer to patent documents 1).

Unexamined-Japanese-Patent No. 5-207746

  However, in a power conversion circuit such as a snubberless circuit, it is necessary to reduce the wiring inductance between the switching element and the DC capacitor as much as possible in order to suppress the surge voltage at turn-off. As described above, in the case of a circuit in which the wiring inductance between the switching element and the DC capacitor is reduced, the short circuit current at the time of the short circuit of the switching element is increased. When the short circuit current increases, the electromagnetic force causes problems such as deformation of the conductor, which is not desirable.

  Then, the objective of this invention is providing the power converter device which can suppress the short circuit current at the time of the short circuit of a switching element.

A power converter according to an aspect of the present invention comprises a switching element forming a power converter circuit;
A DC capacitor, the switching element and the DC capacitor, which are arranged between the switching element and the DC capacitor on the same straight line and which constitute the power conversion circuit, the switching element and the DC capacitor And an electrically connected conductor. The conductor has a length having a wiring inductance that suppresses a current when the switching element is shorted.

  ADVANTAGE OF THE INVENTION According to this invention, the power converter device which can suppress the short circuit current at the time of the short circuit of a switching element can be provided.

The side view showing the side of the composition of the chopper cell concerning a 1st embodiment of the present invention. The top view which shows the upper surface of a structure of the chopper cell which concerns on 1st Embodiment. FIG. 2 is a circuit diagram showing a module circuit of the power conversion device according to the first embodiment. The side view which shows the side of a structure of the chopper cell which concerns on the 2nd Embodiment of this invention. The top view which shows the upper surface of a structure of the chopper cell which concerns on 2nd Embodiment. The circuit diagram showing the module circuit of the power converter concerning a 2nd embodiment.

First Embodiment
FIG. 1 is a side view showing the side of the configuration of the chopper cell 1 according to the first embodiment of the present invention. FIG. 2 is a top view showing the top of the configuration of the chopper cell 1 according to the first embodiment. FIG. 3 is a circuit diagram showing a module circuit 10 of the power conversion device according to the first embodiment. The same reference numerals are given to the same parts in the drawings, and duplicate explanations are omitted.

  The chopper cell 1 includes two switching element stacks 2, two diode stacks 3, a base plate 9, a smoothing capacitor (DC capacitor) 4, and seven conductors (wirings) L1, L2, and L3.

  The base plate 9 is a base on which the elements, components and the like constituting the chopper cell 1 are mounted. The base plate 9 is processed so as to secure an area for mounting elements and the like and to avoid an extra space. For example, a hole HL is formed in a portion of the base plate 9 where the elements and the like are not mounted. Thereby, weight reduction of the base plate 9, reduction of material cost, etc. can be performed. For example, the base plate 9 may be an insulating plate, and supports the switching element stack 2, the diode stack 3, and the smoothing capacitor 4 with a support or the like, not shown, as a metal plate or metal or insulator frame structure. The chopper cell 1 may be configured by a structure. Here, the base plate 9 is described as a flat plate having a rectangular flat surface, but any structure in which the switching element stack 2, the diode stack 3 and the smoothing capacitor 4 are arranged on the same straight line It may be of such a shape. Here, arranging a plurality of objects on the same straight line means that at least one straight line passing through all the arranged objects can be drawn.

  The smoothing capacitor 4 is provided at a position (right side in FIGS. 1 and 2) from the longitudinal center of the surface of the base plate 9 toward one end. The smoothing capacitor 4 may be provided so as to float from the surface of the base plate 9 by a support member or the like. The smoothing capacitor 4 is not limited to one configured by one capacitor. The smoothing capacitor 4 may be composed of a plurality of capacitors connected in series or in parallel.

  One switching element 2 e is built in each of the two switching element stacks 2. For example, the switching element 2e is an injection enhanced gate transistor (IEGT). The switching element stack 2 is provided at a position (left side in FIGS. 1 and 2) from the center in the longitudinal direction of the surface of the base plate 9 toward one end opposite to the smoothing capacitor 4. The two switching element stacks 2 are provided in the direction perpendicular to the longitudinal direction of the surface of the base plate 9. The switching element stack 2 may be provided to float from the surface of the base plate 9 by a support member or the like. The two switching element stacks 2 are electrically connected by a conductor L3. Thereby, the two switching elements 2e of the two switching element stacks 2 are connected in series. In place of the two switching element stacks 2, one switching element stack in which two switching elements 2e are built may be provided.

  The smoothing capacitor 4 is electrically connected to the two switching element stacks 2 by two conductors L1 (positive electrode side conductor and negative electrode side conductor). Thus, the smoothing capacitor 4 is connected in parallel with the two switching elements 2 e connected in series of the two switching element stacks 2.

  The two diode stacks 3 each include a diode. Two diode stacks 3 are provided between the smoothing capacitor 4 on the surface of the base plate 9 and each of the two switching element stacks 2. Thus, the two diode stacks 3 are arranged on the same straight line as the switching element stack 2 and the smoothing capacitor 4 respectively. The two diode stacks 3 may be provided to be floated from the surface of the base plate 9 by a support member or the like. The two diode stacks 3 are electrically connected to the two switching element stacks 2 by the two conductors L2 (positive electrode side conductor and negative electrode side conductor) respectively. Thus, the diodes of the two diode stacks 3 are connected in antiparallel to the switching elements 2 e of the two switching element stacks 2 respectively.

  The module circuit 10 is a power conversion circuit configured to connect two chopper cells 1 in series to form two stages. The chopper cell 1 is a snubberless circuit. The connection point (where the conductor L3 is located) of the two switching element stacks 2 (two switching elements 2e) of each of the two chopper cells 1 serves as an AC terminal of the module circuit 10 and other chopper cells and power supply circuits not shown. Connected to the bus etc. 1 and 2 do not show busses connected to other chopper cells or power supply circuits. Furthermore, the two chopper cells 1 may be configured by one base plate 9.

  A conductor L1 electrically connecting the smoothing capacitor 4 and the switching element stack 2 has a wiring inductance Ls according to the length. In order to increase the distance between the smoothing capacitor 4 and the switching element stack 2, the diode stack 3 is disposed between the smoothing capacitor 4 and the switching element stack 2. As a result, the length of the conductor L1 connecting the smoothing capacitor 4 and the switching element stack 2 becomes longer, so the wiring inductance Ls increases. Thus, the short circuit current which flows at the time of the short circuit of the switching element 2e is suppressed by making the wiring inductance Ls increase. In FIGS. 1 and 2, the bus L1 has a linear shape, but may have a bent structure or a curved structure to adjust its length in order to obtain a necessary wiring inductance.

  According to the present embodiment, the following effects can be obtained.

  Here, in order to suppress the surge voltage, the distance between the smoothing capacitor 4 and the switching element stack 2 needs to be short. Thus, the length of the conductor L1 electrically connecting the smoothing capacitor 4 and the switching element stack 2 is shortened, and the wiring inductance Ls is reduced to suppress the surge voltage. Such a method of suppressing the surge voltage is performed, for example, with a module configuration of a snubberless circuit.

  However, when the wiring inductance Ls is reduced, the short circuit current flowing when the switching element 2e is shorted is increased. When the short circuit current increases, for example, there is a possibility of causing an adverse effect such as deformation of the wiring of the conductors L1 to L3 and the like due to the electromagnetic force of the short circuit current.

  Therefore, the diode stack 3 is interposed between the smoothing capacitor 4 and the switching element stack 2 so as to extend the distance between the smoothing capacitor 4 and the switching element stack 2, and they are arranged on the same straight line. The wiring inductance Ls of the conductor L1 electrically connecting the smoothing capacitor 4 and the switching element stack 2 can be increased.

  Thereby, the power conversion device which mounts the module circuit 10 can suppress the peak of the short circuit current at the time of the short circuit of the switching element 2e. Thereby, deformation of the conductor or the like due to the electromagnetic force of the short circuit current can be prevented.

  Further, by arranging the diode stack 3 which is a component of the power conversion device between the smoothing capacitor 4 and the switching element stack 2, the space on the surface of the base plate 9 can be effectively used. In place of the diode stack 3, other components (elements and the like) constituting the power conversion device may be arranged.

Second Embodiment
FIG. 4 is a side view showing the side of the configuration of the chopper cell 1A according to the second embodiment of the present invention. FIG. 5 is a top view showing the top of the configuration of the chopper cell 1A according to the second embodiment. FIG. 6 is a circuit diagram showing a module circuit 10A of the power conversion device according to the second embodiment.

  In the chopper cell 1 according to the first embodiment shown in FIGS. 1 and 2, the chopper cell 1A is provided with a surge suppression capacitor (DC capacitor) 5 and two wiring conductors L4. The module circuit 10A is configured by a chopper cell 1A instead of the chopper cell 1 according to the first embodiment. The other points are the same as in the first embodiment.

  The surge suppression capacitor 5 is provided on the side of the switching element stack 2 opposite to the diode stack 3 in the longitudinal direction of the surface of the base plate 9. The surge suppression capacitor 5 is electrically connected to the two switching element stacks 2 by two wiring conductors L4 (positive electrode side conductor and negative electrode side conductor). The surge suppression capacitor 5 is connected in parallel to the two switching elements 2e connected in series. The surge suppression capacitor 5 is a capacitor provided to suppress a surge voltage. The surge suppression capacitor 5 has a capacitance smaller than that of the smoothing capacitor 4.

  According to the present embodiment, in addition to the effects of the first embodiment, the surge voltage can be suppressed by providing the surge suppression capacitor 5.

  The surge suppression capacitor 5 is not limited to the portion described in the second embodiment, and may be provided anywhere. For example, the surge suppression capacitor 5 may be disposed anywhere on the surface of the base plate 9 in an open space. For example, the surge suppression capacitor 5 may be on the switching element stack 2. Further, the positions of the surge suppression capacitor 5 and the diode stack 3 may be interchanged.

  The present invention is not limited to the above embodiment as it is, and at the implementation stage, the constituent elements can be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components in different embodiments may be combined as appropriate.

  DESCRIPTION OF SYMBOLS 1 ... Chopper cell, 2 ... Switching element stack, 3 ... Diode stack, 4 ... Smoothing capacitor, 9 ... Base board, L1-L3 ... Conductor.

Claims (6)

A switching element that constitutes a power conversion circuit;
DC capacitor,
A component which is disposed between the switching element and the DC capacitor on the same straight line as the switching element and the DC capacitor and which constitutes the power conversion circuit;
A conductor electrically connecting the switching element and the DC capacitor ;
Said conductor, a power conversion device comprising a length der Rukoto having a current suppressing wiring inductance when the switching element is short-circuited. The power converter according to claim 1, wherein the power converter circuit is a snubberless circuit. The power conversion device according to claim 1, wherein the component is a diode connected in antiparallel with the switching element. The power conversion device according to any one of claims 1 to 3, further comprising: a surge suppression capacitor connected to the switching element to suppress a surge voltage. The power conversion device according to claim 1, wherein the component is a surge suppression capacitor connected to the switching element to suppress a surge voltage.   And a base plate on which the switching element, the capacitor, and the component are mounted,
  The said base plate has a 1st opening between the said switching element and the said components, and has a 2nd opening between the said components and the said capacitor | condenser. The power converter according to claim 1.

Images