JP2005287267A - Power converting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power converting device provided with the arrangement structure of each power module that sharply reduces a surge-generating factor itself, by decreasing floating inductance that is generated between the power modules to a limit. <P>SOLUTION: Both power modules 4a, 4b are arranged via an insulating plate 13 in such a way that the collector terminal 7a and the emitter terminal 8a of the power module 4a that constitutes a positive side arm face the emitter terminal 8b and collector terminal 7b respectively of a power module 4b that constitutes a negative side arm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power conversion device to which a power module incorporating a self-extinguishing semiconductor element and a diode connected in reverse parallel thereto is applied. In particular, the mounting technology of the power converter that suppresses the stray inductance in the power converter as much as possible to reduce the surge generated by the switching operation of the power module and at the same time suppress the current imbalance between multiple terminals provided in the power module It is about.

  A conventional power conversion device is disclosed in FIG. The figure shows a circuit structure when the power converter is a three-level inverter. In the three-level inverter, the DC power supply has three different potentials, and each potential of the DC power supply can be selectively output to the output terminal by controlling the conduction state of the four switches and the two diodes. The three-level inverter has two power modules containing IGBTs and diodes connected in reverse parallel thereto and one power module containing only diodes on one side of the cooling substrate, and is connected in reverse parallel to other IGBTs. Two power modules containing a built-in diode and one power module containing only a diode are mounted on the other surface of the cooling substrate. Moreover, the electrode terminal of each power module is connected by a conductor bus bar provided with a through hole as appropriate, and a snubber circuit component is provided.

  Another conventional power conversion device is disclosed in FIG. The figure shows a circuit structure when the power converter is a two-level inverter. In the two-level inverter, the DC power supply has two different potentials, and each potential of the DC power supply can be selectively output to the output terminal by controlling the conduction state of the two switches. The two-level inverter constitutes one phase by mounting two power modules constituting a positive arm and a negative arm on one surface having a cooling substrate. Specifically, the collector terminal of the power module that constitutes the positive arm of the two-level inverter is adjacent to the emitter terminal of the power module that constitutes the negative arm, and the emitter terminal of the power module that constitutes the positive arm is negative. It arrange | positions so that the collector terminal of the power module which comprises a side arm may mutually adjoin. Connect the positive conductor of the DC power supply of the power converter to the collector terminal of the power module of the positive arm, and connect the negative terminal of the DC power supply of the power converter to the emitter terminal of the power module of the negative arm. The negative terminal conductor is connected, and the emitter terminal of the power module of the positive arm and the collector terminal of the power module of the negative arm are connected to the output terminal conductor connected to the load. Furthermore, the positive side conductor and the negative side conductor are arranged so as to be close to each other through an insulating plate.

  Still another conventional power conversion device is disclosed in FIG. This figure is a diagram showing a circuit structure when the power conversion device is a two-level inverter and each arm is configured by connecting a plurality of power modules in series. A power module similar to the method disclosed in Patent Document 1 is used. FIG. 3 of the document 3 also shows a structure different from that in FIG. 1 in which the electrodes of the power module face each other.

Japanese Patent Laid-Open No. 10-201249 (page 8, FIG. 1) JP 2000-295868 (Page 7, FIGS. 1 and 3) US Pat. No. 5,835,362 (first page, FIG. 1)

  However, for example, in the case of a power conversion device that constitutes a vehicle propulsion system, a large current output is required because the capacity of an electric motor serving as a load tends to increase as the vehicle speed increases. The power modules used for such applications are becoming increasingly large in current, and when a single power module cannot supply a desired current, a plurality of power modules may be connected in parallel. On the other hand, in order to reduce the power loss that increases due to the increase in the motor current, the power converters are increasing in voltage output. Attempts have been made to design the rated voltage of the power module high, rather than connecting the power modules in series to increase the voltage. As a result, there are power modules exceeding 6 kV at present.

  As the power module increases in current and voltage, the surge voltage generated when the power module switches increases. In order to reduce the switching loss of the power module, it is essential to suppress the surge voltage. When the value of the stray inductance due to the inside of the filter capacitor or the power module constituting the power converter or the bus bar for electrically connecting them is large, the surge voltage becomes high. In other words, when the capacity of the power converter is increased, if the stray inductance is not sufficiently reduced, it is necessary to suppress a surge voltage by connecting a snubber circuit consisting of a capacitor, a resistor, and a diode if necessary. is there. Among conventional power converters, Patent Document 1 and Patent Document 2 also disclose a method of mounting a snubber circuit component because of the possibility of this problem. The surge voltage is absorbed by the capacitor that is a component of the snubber circuit, but the absorbed energy is consumed through the resistor. The loss at this resistor increases in proportion to the number of switchings. Therefore, the application of the snubber circuit causes a reduction in device efficiency, and the reliability of the device also decreases.

  The present invention has been made to solve the above-described problems. By reducing the stray inductance to the limit, the surge generation factor itself can be greatly reduced, and at the same time, the current imbalance in the power module can be reduced. Realize a power converter with an arrangement configuration of each power module that does not occur due to external factors of the module, eliminate the parts of the circuit (for example, snubber circuit) for surge suppression, and improve the reliability of the device itself An object of the present invention is to provide a power converter that can be reduced in size, cost, and maintainability.

  In the power conversion device according to the present invention, a positive arm and a negative arm connected in series with each other are connected between both positive and negative poles of a DC power source, and from a connection point between the positive arm and the negative arm. A positive power module group and a negative power module group each having at least one power module including a switching element and a diode connected in reverse parallel to the switching element. In the power converter for converting power between the DC power supply and the output terminal by the on / off operation of the switching element, each power module has a positive electrode and a negative electrode on one surface (electrode forming surface) of its outer shape. The positive-side power module group and the negative-side power module group are connected to the electrodes of the respective power modules. Arranged so that the planes face each other at a predetermined interval and the energization path of the change current flowing between the power modules when the switching element is turned on or off is a reciprocating path that faces each other at the predetermined interval. It is.

  In the power conversion device according to the present invention, the change current flowing between the power modules when the switching element is turned on or turned off flows so as to reciprocate through the energization paths facing each other through a small predetermined interval. The generated magnetic flux and the magnetic flux generated by the current flowing in the return path cancel each other, and the stray inductance in this portion is greatly reduced, and accordingly, the surge voltage is also greatly reduced.

Hereinafter, an inverter device which is a power converter according to the present invention will be described with reference to a plurality of drawings.
Embodiment 1 FIG.
This embodiment will be described with reference to the drawings. In the following drawings, the same reference numerals denote the same or corresponding members. FIG. 1 shows a circuit configuration realized by the first embodiment of the present invention. 2 to 6 are diagrams showing a process of realizing the structure of the power conversion apparatus of FIG. 1, and particularly FIG. 6 is a final structure of the apparatus showing the present invention.

  FIG. 1 shows a two-level inverter, which includes a DC power source 1, a filter capacitor 2, and an inverter unit 3 having two different potential levels of an anode P and a cathode N. The DC power supply 1 may be a DC overhead line or an output of a rectifier circuit. The inverter unit 3 includes a power module 4a constituting a positive arm and a power module 4b constituting a negative arm. The power module 4a includes an IGBT 5a and a diode 6a connected in reverse parallel thereto. The power module 4a includes a collector terminal 7a that is a positive electrode and an emitter terminal 8a that is a negative electrode. A connection point between the emitter terminal 8a of the power module 4a and the collector terminal 7b of the power module 4b is an output terminal 9 connected to a load. The switching state between the IGBT 5a and the IGBT 5b is in a reciprocal relationship. That is, during the period when the ON signal is applied to the gate of the IGBT 5a, the OFF signal is applied to the gate of the IGBT 5b and the potential of the output terminal 9 becomes P. Conversely, during the period when the ON signal is applied to the gate of the IGBT 5b. In this case, an off signal is applied to the gate of the IGBT 5a, and the potential of the output terminal 9 becomes N. Although it is possible to simultaneously provide an off signal to the gate terminals of the IGBT 5a and the IGBT 5b, an on signal is not simultaneously provided during normal operation.

  FIG. 1 illustrates a case where the power module 4c is connected in parallel to the power module 4a and the power module 4d is connected in parallel to the power module 4b for the purpose of providing more versatility. The power modules 4a and 4c or the power modules 4b and 4d are basically controlled to be in the same switching state.

Next, the internal structure will be described while explaining the assembly process of the power conversion apparatus with reference to FIGS. In order to provide more versatility, the case where so-called two power modules are connected in parallel, in which the same switching signal is applied to each of the power modules 4a and 4c and the power modules 4b and 4d as in FIG. To do.
FIG. 2 is a diagram illustrating a state where the power modules 4b and 4d, which are negative arms, are mounted on the cooling substrate 10b. In the power module 4b, the surface on the right front side in FIG. 2 is an electrode formation surface, and a collector terminal 7b and an emitter terminal 8b are formed. Here, each is composed of three electrode terminals. The back surface of the electrode forming surface, that is, the left back surface in FIG. 2 is a heat radiating surface for the heat generated by the power module 4b, and the cooling substrate 10b is in contact with this heat radiating surface. Other power modules have the same configuration. The conductor 17b is for forcibly setting the gate electrode and the emitter electrode of the power modules 4b and 4d connected in parallel to the same potential. The conductor 17b is not necessary when not connected in parallel.

  FIG. 3 shows a conductor 11 for electrically connecting the emitter terminals 8b and 8d of each of the power modules 4b and 4d and the N potential of the DC power supply 1 in addition to FIG. 2, and a collector terminal of each of the power modules 4b and 4d. It is the figure where the conductor 12 for electrically connecting 7b and 7d and the output terminal 9 (9b) was attached. The head portions of the bolts 18a to 18l for attaching the conductors 11 and 12 are shaped to be filled with the thickness portions of the conductors 11 and 12, as shown.

FIG. 4 is a view in which the insulating plate 13 is inserted along the guide pins 14a to 14d fixed to the cooling substrate 10b. It goes without saying that various methods other than the guide pins can be adopted for fixing and positioning the insulating plate 13 shown here.
FIG. 5 shows a configuration of the positive arm, and a conductor 15 for electrically connecting the collector terminals 7a and 7c of the power modules 4a and 4c mounted on the cooling substrate 10a and the P potential of the DC power source 1, It is the figure where the conductor 16 for electrically connecting the emitter terminals 8a and 8c of each power module 4a and 4c and the output terminal 9 (9a) was attached with the volt | bolts 18m to 18x.
6 is a view in which the cooling substrate 10a of FIG. 5 is inserted and fixed along the guide pins 14a to 14d in FIG. This figure is a diagram showing an essential configuration of the present invention, and its features will be described with reference to FIG.

  FIG. 7 shows a view of the structure of FIG. 6 as viewed from the left front direction. In this way, the power module 4a (4c) of the positive arm and the power module 4b (4d) of the negative arm are arranged so that the electrodes face each other, and the collector terminal 7a (7c) of the power module 4a (4c) ), The emitter terminals 8a (8c) are arranged in a face-to-face state without shifting to the emitter terminal 8b (8d) and the collector terminal 7b (7d) of the power module 4b (4d). As a result, the reciprocating path that returns from the potential P of the conductor 15 to the potential N of the conductor 11 through the output terminal 9a of the conductor 16 and further through the conductor 12 of the output terminal 9b can be completely opposed at a small interval. For example, reverse recovery currents of the diodes 6b and 6d generated by the turn-on operation of the IGBTs 5a and 5c flow through the thick lines in FIG. In the figure, a thick dotted line indicates a current path inside the power module package. The change in the magnetic flux generated by this current is the same as the change in the magnetic flux generated by the current flowing through the output terminal 9 via the IGBTs 5a and 5c, and the direction is reversed. It has a so-called mutual bond relationship. Therefore, the structure is such that the effect of canceling the magnetic flux generated by the change current flowing through this path is maximized. That is, the stray inductance can be suppressed to the maximum, and the surge voltage can be suppressed to the maximum.

  When the load current flowing from the P potential of the DC power supply 1 to the output terminal 9 is cut off by the turn-off operation of the IGBTs 5a and 5c, the current flows from the N potential to the output terminal 9 via the diodes 6b and 6d. Operation occurs. In this commutation operation period, the decrease rate of the current flowing through the IGBTs 5a and 5c is the same as the increase rate of the current flowing through the diodes 6b and 6d. This current path is the same as the path through which the reverse recovery current flows, and the mutual coupling relationship is established. That is, the structure is such that the effect of canceling the magnetic flux generated by the current flowing through this path is maximized. That is, the stray inductance can be suppressed to the maximum, and the surge voltage can be suppressed to the maximum.

In the conventional power conversion device described above, the electrode positions of the power modules of the positive arm and the negative arm are intentionally shifted, or the reverse recovery current of the diode is concentrated around the adjacent electrodes. The stray inductance may not be sufficiently reduced, and a surge voltage generated due to a change in magnetic flux generated transiently by the switching operation of the IGBT 5 and the diode 6 constituting the power module 4 needs to be suppressed by the snubber circuit.
However, the surge voltage can be minimized by adopting a structure having the arrangement of the power modules 4a to 4d as shown in FIGS.
Specifically, as a result of trial manufacture by the inventors, for example, when the thicknesses of the conductors 11, 12, 15, 16 for filling the head portions of the bolts 18a to 18x are 12 mm, and the thickness of the insulating plate is 3 mm, The stray inductance existing in the path from the P potential side of the conductor 15 to the N potential side of the conductor 11 could be suppressed to a level not exceeding 100 nH. As a result, the snubber circuit can be eliminated.

  As described above, the collector terminal 7 and the emitter terminal 8 of the normal power module 4 are composed of several divided terminals as shown in FIG. For this reason, the generation of surge voltage and the shape processing of the conductor may cause the current flowing through the divided terminals constituting the collector terminal 7 and the emitter terminal 8 to be non-uniform. However, in the present invention, as can be seen from FIG. 7, since the terminals divided in the direction perpendicular to the direction in which the change current flows are arranged, the paths flowing through the terminals are parallel to each other, and as a result, between the terminals. Not only the current but also the change current between the power modules 4a and 4c or between the power modules 4b and 4d can be made uniform.

  In the structure shown in FIG. 7, the conductors 11, 12, 15, 16 and the terminals such as the power modules 4 a, 4 b do not interfere with each other, so the insulating plate 13 is integrated with the conductors 11, 12, 15, 16. In addition to the need to provide through holes in the conductors 11, 12, 15, and 16 as seen in conventional power converters, the internal impedance of the conductors is suppressed as much as possible. Can do.

Embodiment 2. FIG.
In the second embodiment, various methods for connecting the bus bars 15 and 11 connected to the P potential and N potential of the DC power source 1 shown in FIGS. 3 and 5 and the filter capacitor 2 are proposed. FIG. 8 is a diagram in which the filter capacitors 2a and 2b and the structure of the inverter unit 3 shown in FIG. 6 are arranged upside down. Regarding the filter capacitor 2a, the electrodes 19a and 19b are connected to the potential N, and the electrodes 20a and 20b are connected to the potential N, respectively. The same applies to the filter capacitor 2b.
As described above, the electrodes of the filter capacitors 2a and 2b and the conductors 15 and 11 constituting the DC side terminal are drawn out in the same direction (upward in FIG. 8). Here, the electrodes 19a of the filter capacitors 2a and 2b are further here. To 19d and the electrodes 20a to 20d are set on the same plane as the surfaces of the terminal connecting portions of the conductor 11 and the conductor 15. In this state, the conductor 15 constituting the potential P and the conductor constituting the potential N are arranged in parallel via the insulating plate, and the terminal 15 of the conductor 15 and the terminals 20a to 20d of the filter capacitors 2a and 2b, and the conductor 11 It is possible to connect the terminal connection portion and the terminals 19a to 19d of the filter capacitors 2a and 2b.

The procedure for this electrical connection is shown in FIG. It is desirable to reduce the stray inductance by integrating the conductor constituting the potential P, the conductor constituting the potential N, and the insulating plate sandwiched between them. In this case, through holes must be provided, but the positional relationship between the electrodes 19 and 20 of the filter capacitors 2a and 2b and the terminal connection portions of the conductors 11 and 15 should be arranged at equal intervals in both the vertical and horizontal directions as shown in FIG. Therefore, nonuniform flow of each terminal can be prevented beforehand. That is, the stray inductance existing in the path for forming the potential P and the potential N of the DC power supply 1 can be minimized. In addition, when applying the plate-shaped electrodes 19 and 20 shown in FIG. 8, it is preferable that the housing | casing of the filter capacitor 2 is molded with resin. Further, when the housing of the filter capacitor 2 is formed of a conductor instead of a resin mold, a plurality of insulators provided with electrodes can be used.
The number of filter capacitors 2 is not particularly limited, and may be one, or may be connected in parallel as necessary.
Further, FIG. 8 assumes the use of bolts for the connection method of the conductor constituting the potential P and the conductor constituting the potential N to the terminal connection portions of the filter capacitors 2a and 2b and the conductors 11 and 15, although not shown. It is also possible to use a connector of the type.

Embodiment 3 FIG.
Here, the point in the case where the parallel number of the power modules 4 is increased will be described. That is, FIG. 6 shows a structure in the case where two power modules 4 constituting the positive arm are connected in parallel. In the present invention, it is meaningless to limit the number of units connected in parallel. For example, when three units are connected in parallel, it can be realized by arranging three power modules 4. Accordingly, the shape may be changed by extending the conductor 17b shown in FIG. 2, increasing the size of the filter capacitor 2 shown in FIG. 8, or increasing the number of electrodes.
Further, the bus bars 15 and 11 for connecting to the potential P and the potential N shown in FIGS. 3 and 5 are applied as they are, but the conductor 12 connected to the output terminal 9 is connected to the power modules 4b and 4d, and the conductor 16 is connected. Is separated into power modules 4a and 4c, two independent output terminals 9 can be formed. For example, if three power modules 4 are arranged, three independent output terminals 9a, 9b, 9c can be formed using a set of cooling substrates 10a, 10b.

Embodiment 4 FIG.
Here, the circuit configuration when the inverter unit 3 has a three-phase configuration will be described with reference to FIG. As described in the third embodiment, even if the power modules 4 in FIG. 6 are arranged in the same manner, a three-phase output can be obtained. Here, a structure for obtaining a three-phase output with another bus bar configuration will be described. FIG. 11 shows the specific structure. The conductors forming the three independent output terminals 91, 92, 93 were conductors 16a, 16b, 16c for the positive arm and conductors 12a, 12b, 12c for the negative arm. The conductor for connecting the potential P to each power module 4a, 4c, 4e is the conductor 15 as in FIG. 5, and the conductor for connecting the potential N to each power module 4b, 4d, 4f is the same as in FIG. A conductor 11 was obtained.

FIG. 12 shows a state in which the conductor 15 and the conductor 11 are removed from the state of FIG. In order to obtain a structure as shown in FIG. 6, the two left and right assemblies shown in FIG. 11 are combined so that the cooling substrates 10a and 10b and the conductor 15 and the conductor 11 are parallel to each other. At this time, it is necessary to insert an insulator between the conductor 15 and the conductor 11, between the conductors 16a, 16b and 16c and the conductor 15, and between the conductors 12a, 12b and 12c and the conductor 11. Therefore, in such a case, for example, it may be considered to be a laminated bus bar in which the conductors 11 and 15 are integrated with an insulator.
What is important here is the difference from FIG. The difference is how the power modules are arranged, and the arrangement of the power modules and the bus bar structure for suppressing stray inductance are the same.

Embodiment 5 FIG.
In the previous embodiment, a specific example of the power module 4 has been described in which the IGBT 5 and the diode 6 are incorporated. However, the power module 4 is not particularly limited to the IGBT, and a MOSFET or other self-extinguishing half is used as a conductor. It may be an element.
Further, the material for forming the self-extinguishing semiconductor element and the diode may be silicon, and the new semiconductor material may be, for example, silicon carbide or diamond.

Embodiment 6 FIG.
As described in the previous embodiment, the liquid cooling cooling method can be applied to the cooling substrates 10a and 10b as long as a coolant can be passed through the cooling substrates 10a and 10b. In addition, if a heat sink is attached to the substrate itself, an air cooling cooling system can be applied.
Further, in the example of FIG. 8, the cooling substrate 10 may be designed as one responsible for cooling both the power module 4 and the filter capacitor 2. Therefore, it is obvious that various cooling methods can be applied to the present invention.

Embodiment 7 FIG.
Each of the previous embodiments is applied to a two-level inverter. In the seventh embodiment, a case where the present invention is applied to a three-level inverter will be described. FIG. 13 shows the main circuit configuration.
In FIG. 13, a first power module 4 a and a second power module 4 b connected in series as a positive power module group are connected between the P potential of the DC power source 1 a and the output terminal 9. Further, a first diode module 21a that functions as a clamp diode is connected between a connection point X of both power modules 4a and 4b and a potential C that is a neutral pole of the DC power supply. A third power module 4c and a fourth power module 4d connected in series as a negative power module group are connected between the N potential of the DC power source 1b and the output terminal 9. Further, a second diode module 21b is connected between the connection point Y between the power modules 4c and 4d and the potential C of the DC power supply.

14 and 15 show specific structures thereof. In FIG. 14, the conductor 24 on the positive side (right side in the figure) is a conductor that connects the anode terminal 8e of the first diode module 21a to the potential C, and the conductor 16 is from the emitter terminal 8b of the second power module 4b. The conductor constituting the output terminal 9a and the conductor 22 are conductors constituting the connecting portion X in FIG.
Further, the negative side (left side in the figure) conductor 25 is a conductor that connects the cathode terminal 7f of the second diode module 21b to the potential C, and the conductor 12 is an output from the collector terminal 7c of the third power module 4c. The conductor constituting the terminal 9b, the conductor 23, is a conductor constituting the connecting portion Y in FIG.
FIG. 15 shows a state in which the conductor 23 and the conductor 24 are removed from the state of FIG. The positive-side conductor 15 is a conductor that connects the collector terminal 7a of the first power module 4a to the potential P, and the negative-side conductor 11 is a conductor that connects the emitter terminal 8d of the fourth power module 4d to the potential N. is there.

The power modules 4a and 4b and the diode module 21a are mounted on the cooling substrate 10a on the positive side, and the power modules 4c and 4d and the diode module 21b are mounted on the cooling substrate substrate 10b on the negative side. The cooling substrates 10a and 10b are arranged according to FIG. 6 so that the electrodes 21a and the power module 4d and the power modules 4b and 4c face each other.
Since the bus bar structure is the essence of the present invention, the illustration of the insulator between the conductors that needs to be inserted is omitted.

If the diode modules 21a and 21b in FIG. 13 are provided with IGBTs 5e and 5f connected in reverse parallel to the diodes 6e and 6f in the module, as shown in FIG. In particular, the electrode shape of the power module and its arrangement can be made equal. In this case, the notations 4e and 4f are valid in FIGS. In this case, the gate signals of the IGBTs 5e and 5f constituting the power modules 4e and 4f are in an off state or an equivalent state, and it is not necessary to input an on signal.
For the power modules 4e and 4f, on the condition that the electrodes can face each other, the same package as the other power modules 4a to 4d is used, but only the diodes 6e and 6f are incorporated without incorporating the IGBTs 5e and 5f. May be applied.

  In the present invention, as shown in FIG. 15, the power modules are arranged in the order of the power modules 4a, 4e (diode modules 21a), 4b from the bottom with respect to the positive cooling substrate 10a. About the board | substrate 10b, it arranges in order of the power module 4f (diode module 21b), 4d, and 4c from the bottom. This arrangement ensures that the current having the same rate of change and the opposite direction, which is the essence of the present invention, always flows when the load current is commutated in the opposite conductor, and the effect of reducing stray inductance due to mutual coupling is ensured. Maximized.

  FIG. 17 is a simplified front view of the three-level inverter shown in FIGS. 14 and 15. This explains the commutation path of the load current and the mutual coupling relationship. Each thick line in the figure represents the current in the initial state. In FIG. 17 (1), the load current is in the initial state when it flows through the path C → 8e → 7e → 7b → 8b → 9. When the IGBT 5a of the power module 4a is turned on from this state, the reverse recovery current of the diode 6e flows through a path of P → 7a → 8a → 7e → 8e → C. Further, the load current is commutated in a path of P → 7a → 8a → 7e → 7b → 8b → 9. Therefore, there is no change in the current flowing from 7e to 9, and the current flowing from P to 7e and the current returning from 7e to C are opposite in direction and accompanied by the same rate of current change. That is, the change current accompanying the turn-on flows from P to C.

  Next, in FIG. 17 (2), the state in which the load current flows through the route of N → 8d → 7d → 8c → 7c → 9 is set as an initial state. When the IGBT 5b of the power module 4b is turned on from this state, the reverse recovery current of the diode 6d flows through a path of C → 8e → 7e → 7b → 8b → 7c → 8c → 7d → 8d → N. As a result, the load current is commutated in a path of C → 8e → 7e → 7b → 8b → 9. Therefore, the current flowing from C to 8b and the current returning from 7c to N are opposite in direction and accompanied by the same current change rate. Thus, according to the present invention, the relationship as shown in FIG. 7 showing the two-level inverter can be maintained even in the commutation operation of the three-level inverter. In other words, the power modules are arranged so that the power modules with current in and out always face each other, and the effect of reducing stray inductance due to mutual coupling is great.

In FIG. 17, there are cases where the current directions are opposite to those shown in the figure, but the fact that the floating inductance is reduced through the reciprocating path through the interval where the change current between the power modules is small is shown in FIG. 17. Is exactly the same.
In particular, in FIG. 17A, a reciprocal path of a change current in which the inductance is reduced is formed in the positive module, and the arrangement structure of the module shown in the figure is more effective in suppressing stray inductance. I understand that.

Although illustration is omitted, it is obvious that even when the modules are arranged as follows, it is effective in reducing stray inductance for the same reason as in the above example.
That is, the arrangement order of the modules shown in FIGS. 14, 15 and 17 is arranged in the order of power modules 4a and 4e (diode modules 21a) and 4b from the bottom on the positive side, and from the bottom on the negative side. The modules 4f (diode module 21b), 4d, and 4c are arranged in this order, but the same effect can be obtained by changing only the negative arrangement from the bottom to the power modules 4d, 4f (diode module 21b), and 4c. can get.

  In the above description, the gate drive circuit and the like are not shown, but are necessary in an actual power converter. In addition, there may be a need for a housing for supporting the filter capacitor and the inverter unit. Here, the essential structure of the power conversion device of the present invention has been described. However, even if changes within a range that can easily be considered by those skilled in the art within the range in which the arrangement of the power modules is not largely changed, they are within the scope of the present invention. Needless to say.

As described above, the present invention is as follows.
Since an insulating plate for electrically insulating the positive side power module group and the negative side power module group is inserted within a predetermined interval between the positive side power module group and the negative side power module group, the dimension of the predetermined interval is set. The distance between the reciprocating paths through which the change current flows can be reduced, and the stray inductance can be further reduced.

  Moreover, since the back surface of the electrode formation surface of each power module is configured as a heat dissipation surface, the heat generated by each power module is efficiently dissipated.

  In addition, since the cooling substrate is provided in contact with the heat dissipation surface of the power module and dissipates the heat generated by the power module through the heat dissipation surface, the heat generated by each power module is more strongly dissipated.

  Further, since the cooling substrate uses a liquid refrigerant to dissipate heat, the cooling substrate is small and the cooling capacity is improved.

  In addition, a capacitor connected in parallel with the DC power supply is disposed on the heat radiation surface side of the positive power module group and / or the negative power module group, and the DC side terminals of the positive power module group and the negative power module group Since the capacitor terminals are drawn in the same direction and the two terminals are connected by a planar laminated conductive plate, the DC power terminals of the positive power module group and the negative power module group and the capacitor terminals are connected. It is possible to suppress stray inductance generated at the connection portion.

  Further, since the DC side terminals and the capacitor terminals of the positive side power module group and the negative side power module group are located on the same plane, the stray inductance at the same connection portion can be further reduced.

  The DC power source is a two-level power conversion device that includes a positive side pole and a negative side pole, and outputs two levels of potentials, ie, a positive side pole and a negative side pole, from an output terminal. Group and the negative power module group, the positive electrode and the negative electrode of the power module constituting the positive power module group are respectively connected to the negative electrode and the positive electrode of the power module constituting the negative power module group. Since they are arranged so as to face each other, stray inductance generated between the power modules can be greatly suppressed, the surge voltage applied to the power modules can be suppressed, and further no snubber circuit is required, so the device cost is reduced, and the device A two-level power conversion device with improved efficiency can be realized.

  The DC power supply includes a positive side electrode, a neutral side electrode, and a negative side electrode, and a three-level power converter that outputs three levels of potentials of the positive side electrode, the neutral electrode, and the negative electrode from the output terminal. The positive power module group includes a first power module in which a positive electrode is connected to a positive electrode of a DC power source and a positive electrode connected to a negative electrode of the first power module. Comprises a second power module connected to the output terminal, a negative electrode of the first power module, and a first diode module connected between the neutral pole of the DC power supply, and the negative power module A third power module with the positive electrode connected to the output terminal and the positive electrode connected to the negative electrode of the third power module and the negative electrode connected to the negative pole of the DC power supply. 4 power module and 3rd power module negative And a second diode module connected between the electrode and the neutral pole of the DC power supply. Each diode module has a positive electrode and a negative electrode formed on one surface (electrode formation surface) of its outer shape. The positive power module group and the negative power module group are arranged so that each electrode is positioned on a straight line, and the positive electrode and the negative electrode of the first power module are the second The positive and negative electrodes of the first diode module face the negative and positive electrodes of the fourth power module so that they face the negative and positive electrodes of the diode module, respectively. The positive and negative electrodes of the second power module are respectively connected to the negative and positive electrodes of the third power module. Since the stray inductances generated between the power modules can be greatly suppressed, the surge voltage applied to the power modules can be suppressed, and the snubber circuit is unnecessary, so the device cost is reduced. A three-level power conversion device that improves device efficiency can be realized.

  The DC power supply includes a positive side electrode, a neutral side electrode, and a negative side electrode, and a three-level power converter that outputs three levels of potentials of the positive side electrode, the neutral electrode, and the negative electrode from the output terminal. The positive power module group includes a first power module in which a positive electrode is connected to a positive electrode of a DC power source and a positive electrode connected to a negative electrode of the first power module. Comprises a second power module connected to the output terminal, a negative electrode of the first power module, and a first diode module connected between the neutral pole of the DC power supply, and the negative power module A third power module with the positive electrode connected to the output terminal and the positive electrode connected to the negative electrode of the third power module and the negative electrode connected to the negative pole of the DC power supply. 4 power module and 3rd power module negative And a second diode module connected between the electrode and the neutral pole of the DC power supply. Each diode module has a positive electrode and a negative electrode formed on one surface (electrode formation surface) of its outer shape. The positive power module group and the negative power module group are arranged so that each electrode is positioned on a straight line, and each positive electrode and negative electrode of the first power module is the fourth power module. The positive and negative electrodes of the first diode module face the negative and positive electrodes of the second diode module so that they face the negative and positive electrodes of the power module, respectively. The positive and negative electrodes of the second power module are respectively connected to the negative and positive electrodes of the third power module. Since the stray inductances generated between the power modules can be greatly suppressed, the surge voltage applied to the power modules can be suppressed, and the snubber circuit is unnecessary, so the device cost is reduced. A three-level power conversion device that improves device efficiency can be realized.

  In addition, since the diode module has the same structure as the power module by including a switching element connected in reverse parallel to the diode in the module, the electrode shape and the arrangement of all the modules are changed. It can be made equal, and the arrangement configuration and the conductor shape can be easily designed.

  The power conversion device of the present invention can be applied not only to the inverter device described above, but also to a DC chopper device, etc., and can substantially suppress stray inductance generated between power modules to be used. Since no snubber circuit is required, the device cost can be reduced and the device efficiency can be improved.

It is a figure which shows the circuit structure of the power converter device implement | achieved by Embodiment 1 of this invention. It is a figure which shows a part of structure of the power converter device of FIG. 1, and is a figure explaining an assembly process. It is a figure which shows a part of structure of the power converter device of FIG. 1, and is a figure explaining an assembly process. It is a figure which shows a part of structure of the power converter device of FIG. 1, and is a figure explaining an assembly process. It is a figure which shows a part of structure of the power converter device of FIG. 1, and is a figure explaining an assembly process. It is a figure which shows the circuit structure of the power converter device implement | achieved by Embodiment 1 of this invention. It is a figure explaining the arrangement | positioning of each power module of the power converter device implement | achieved by Embodiment 1 of this invention, and the energization path | route of a change current. It is a figure which shows the circuit structure of the power converter device implement | achieved by Embodiment 2 of this invention. It is a figure which shows the direct current | flow connection part of the power converter device of FIG. It is a figure which shows the circuit structure of the power converter device implement | achieved by Embodiment 4 of this invention. It is a figure which shows a part of structure of the power converter device of FIG. 10, Comprising: It is a figure explaining an assembly process. It is a figure which shows a part of structure of the power converter device of FIG. 10, Comprising: It is a figure explaining an assembly process. It is a figure which shows the circuit structure of the power converter device implement | achieved by Embodiment 7 of this invention. It is a figure which shows a part of structure of the power converter device of FIG. 13, Comprising: It is a figure explaining an assembly process. It is a figure which shows a part of structure of the power converter device of FIG. 13, Comprising: It is a figure explaining an assembly process. It is a figure which shows the circuit structure which modified the power converter device of FIG. 13 partially. It is a figure explaining arrangement | positioning of each power module of the power converter device implement | achieved by Embodiment 7 of this invention, and the energization path | route of a change current.

Explanation of symbols

1, 1a, 1b DC power supply, 2, 2a, 2b filter capacitor,
3 Inverter part, 4, 4a, 4b, 4c, 4d, 4e, 4f Power module,
5, 5a, 5b, 5c, 5d, 5e, 5f IGBT,
6, 6a, 6b, 6c, 6d, 6e, 6f diodes,
7, 7a, 7b, 7c, 7d, 7e, 7f collector terminal,
8, 8a, 8b, 8c, 8d, 8e, 8f Emitter terminal, 9, 9a, 9b Output terminal, 10a, 10b Cooling substrate, 13 Insulating plate, 21a, 21b Diode module.

Claims (11)

Connect the positive and negative arms connected in series to each other between the positive and negative poles of the DC power supply, and pull out the output terminal from the connection point between the positive and negative arms. Each of the arm and the negative arm includes a positive power module group and a negative power module group each including at least one power module including a switching element and a diode connected in reverse parallel to the switching element. In a power conversion device that converts power between the DC power source and the output terminal by an on / off operation,
Each of the power modules has a positive electrode and a negative electrode formed on one surface (electrode formation surface) of the outer shape, and the positive power module group and the negative power module group are connected to the respective power modules. A reciprocating path in which the electrode forming surfaces of the modules face each other with a predetermined interval and the energization paths of the change current flowing between the power modules when the switching element is turned on or turned off face each other with the predetermined distance The power converter characterized by arrange | positioning so that it may become. 2. The power converter according to claim 1, wherein an insulating plate for electrically insulating the positive power module group and the negative power module group is inserted within the predetermined interval. The power converter according to claim 1, wherein each of the power modules is configured such that a back surface of the electrode forming surface is a heat radiating surface. The power conversion device according to claim 3, further comprising a cooling substrate that is in contact with a heat dissipation surface of the power module and dissipates heat generated by the power module through the heat dissipation surface. The power converter according to claim 4, wherein the cooling substrate dissipates heat using a liquid refrigerant. A capacitor connected in parallel with the DC power source is disposed on the heat radiation surface side of the positive power module group and / or the negative power module group, and the DC side of the positive power module group and the negative power module group. 4. The power conversion device according to claim 3, wherein the terminal and the terminal of the capacitor are pulled out in the same direction, and the two terminals are connected by a planar laminated conductive plate. 7. The power conversion apparatus according to claim 6, wherein the DC side terminals of the positive side power module group and the negative side power module group and the terminals of the capacitor are positioned on the same plane. The DC power source includes a positive electrode and a negative electrode, and is a two-level power conversion device that outputs two levels of potentials of the positive electrode and the negative electrode from the output terminal,
The positive side power module group and the negative side power module group are connected to the positive side electrode and the negative side electrode of the power module constituting the positive side power module group, respectively. The power conversion device according to claim 1, wherein the power conversion device is disposed so as to face the side electrode and the positive side electrode. The DC power source includes a positive pole, a neutral pole, and a negative pole, and a three-level power conversion that outputs three levels of potentials of the positive pole, the neutral pole, and the negative pole from the output terminal. A device,
The positive power module group includes a first power module in which a positive electrode is connected to a positive electrode of the DC power source, and a positive electrode connected to a negative electrode of the first power module. A second power module connected to the output terminal; a first diode module connected between the negative electrode of the first power module and a neutral pole of the DC power supply; The side power module group includes a third power module having a positive electrode connected to the output terminal, a positive electrode connected to a negative electrode of the third power module, and a negative electrode connected to the negative side of the DC power source. A fourth power module connected to the pole, a second diode module connected between the negative electrode of the third power module and the neutral pole of the DC power supply,
Each diode module has a positive electrode and a negative electrode formed on one surface (electrode forming surface) of its outer shape,
The positive side power module group and the negative side power module group are arranged such that each electrode is positioned on a straight line, and the positive side electrode and the negative side electrode of the first power module are the second diode. The positive and negative electrodes of the first diode module face the negative and positive electrodes of the fourth power module so that the negative and positive electrodes of the module face each other. 8. The first power module according to claim 1, wherein the positive electrode and the negative electrode of the second power module are arranged so as to face the negative electrode and the positive electrode of the third power module, respectively. The power conversion apparatus of crab. The DC power source includes a positive pole, a neutral pole, and a negative pole, and a three-level power conversion that outputs three levels of potentials of the positive pole, the neutral pole, and the negative pole from the output terminal. A device,
The positive power module group includes a first power module in which a positive electrode is connected to a positive electrode of the DC power source, and a positive electrode connected to a negative electrode of the first power module. A second power module connected to the output terminal; a first diode module connected between the negative electrode of the first power module and a neutral pole of the DC power supply; The side power module group includes a third power module having a positive electrode connected to the output terminal, a positive electrode connected to a negative electrode of the third power module, and a negative electrode connected to the negative side of the DC power source. A fourth power module connected to the pole, a second diode module connected between the negative electrode of the third power module and the neutral pole of the DC power supply,
Each diode module has a positive electrode and a negative electrode formed on one surface (electrode forming surface) of its outer shape,
The positive power module group and the negative power module group are arranged such that the respective electrodes are positioned on a straight line, and the positive electrode and the negative electrode of the first power module are the fourth power. The positive electrode and the negative electrode of the first diode module face the negative electrode and the positive electrode of the second diode module so that the negative electrode and the positive electrode of the module face each other. 8. The first power module according to claim 1, wherein the positive electrode and the negative electrode of the second power module are arranged so as to face the negative electrode and the positive electrode of the third power module, respectively. The power conversion apparatus of crab. 11. The diode module according to claim 9, wherein the diode module is provided with a switching element connected in reverse parallel to a diode in the module, thereby having the same structure as the power module. Power conversion device.

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