JPH088394A - Main circuit configuration of high speed switching device - Google Patents

Abstract

PURPOSE:To reduce floating inductance of each circuit wiring when the main circuit of an inverter or the like is configured by means of a high speed switching device. CONSTITUTION:Power transistor modules 1, 2 having complementary structures, where the main terminals of collector C and emitter E of each transistor are arranged differently, are disposed closely each other so that the distance between main electrodes to be interconnected is minimized thus minimizing the emitter- collector distance between both modules. Consequently, the length of required wiring for a snubber capacitor 6 is minimized and the floating inductance thereof is minimized. Floating inductance 9 of DC feeder bus, extending between both modules 1, 2 and a power supply capacitor 5, can be decreased to zero or thereabout by arranging the positive and negative feeders in parallel and as closely as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a main circuit of a power conversion device such as an inverter device comprising a high speed switching device such as an IGBT having a complementary structure.
More specifically, the present invention relates to a method for configuring a main circuit that suppresses a transient overvoltage when the switching device is turned off.

[0002]

2. Description of the Related Art The conventional arrangement of a main circuit forming a bridge of this kind in a power conversion device is shown in FIG. 6 in which a single-phase inverter is taken as an example and in accordance with the main circuit diagram of FIG. A known main circuit configuration diagram is known. FIG. 7 is a perspective view of the two sets of power transistor modules shown in FIG.

First, the main circuit diagram of FIG. 3 will be described below. In FIG. 3, T _{1 to} T ₄ are power transistors as high-speed semiconductor switching devices and D, respectively.
_{1 to} D ₄ are commutation diodes connected in antiparallel to the transistors T _{1 to} T ₄ , respectively, and 1 to 4 are combinations of the transistors and diodes (T ₁ -D ₁ ).
~ (T ₄ -D ₄ ) packaged power transistor module, 5 is a power supply capacitor functioning as a DC power supply, 6 is a snubber capacitor for suppressing the transient overvoltage at the time of turning off the transistor T ₁ or T ₂ , the same. Reference numeral 7 is a snubber capacitor for suppressing the transient overvoltage at the time of turning off the transistor T ₃ or T ₄ , and 8 is a load containing an inductive component.

Numerals 9 and 15 are stray inductances in the main circuit wiring, and 10 is a stray inductance in the wiring of the snubber capacitor. Next, FIG. 6 is a main circuit configuration diagram relating to upper and lower arm elements for one phase in the main circuit bridge configuration of the single-phase inverter shown in FIG. 3, and a pair of complementary transistor modules having different collector and emitter terminal arrangements. FIG. 3 is a schematic view of a planar arrangement of each component mainly including. It should be noted that the numerals 9, 10, and 15 shown in the drawing are stray inductances in the respective wirings, and for the sake of convenience, they are shown on the assumption that they are concentrated on the wiring conductors shown in the drawing.

Further, FIG. 7 is a perspective view of a pair of complementary structure power transistor modules which are combined corresponding to the arrangement shown in FIG. In this case, the transistor driving signal line (base / emitter line) does not intersect the main circuit wiring as shown in the figure.

[0006]

Generally, when a circuit configuration is made up of high-speed switching elements, a counter electromotive voltage generated due to the stray inductance of the circuit wiring conductor itself accompanying the high-speed switching of the circuit current is the switching element. There is a risk of narrowing the safe operating range of the device, and it is important to reduce the stray inductance of the circuit wiring conductor itself when configuring a high-speed switching circuit.

First, the influence of each of the illustrated stray inductances when the main circuit switching element shown in FIG. 3 changes from on to off will be described. Now, the transistors T ₁ and T ₄ are turned on, and the path of the positive electrode (+ pole) of the capacitor 5 for power supply → transistor T ₁ → load 8 → transistor T ₄ → negative electrode (−pole) of the capacitor 5 If the transistor T ₁ is turned off when the load current flows, the current due to the release of the stored energy in the inductive component of the load 8 becomes the current I _D, and the load 8 → transistor T ₄ → diode D ₂ → load 8 Return to the path. On the other hand, the energy stored in the stray inductance 9 of the main circuit wiring is
It becomes the circulating current I _{SN and is} circulated through the snubber capacitor 6 and the power supply capacitor 5.

Now, the above-mentioned stray inductances 10 and 15
If the values of and are L ₁₀ and L ₁₅ , respectively, then both currents I _SN
And I _D are the counter electromotive voltage L ₁₀ · dI proportional to the current change rate over time, such as the positive and negative (+, −) polarities shown at both ends of the stray inductances 10 and 15, respectively.
To induce and _SN / dt and L ₁₅ · dI _D / dt. Both of the above counter electromotive voltages are the terminal voltage E _{DC of the} power supply capacitor 5.
And is applied between the collector and the emitter of the transistor T ₁ .

[0009] Incidentally 5 is an operation waveform diagram showing a pattern such as back electromotive force described above is superimposed on the terminal voltage E _DC power supply for capacitor 5 with respect to the elapsed time t, I _C and V
_CE is the collector current and collector-emitter voltage of the transistor, respectively. As shown, the current I _C
The voltage V _CE may increase and change significantly, corresponding to two regions in which the currents I _SN and I _D increase with the decrease of the current I and the current I _SN decreases and the current I _D becomes a steady value. There is.

[0010] With respect to the increase fluctuation of the voltage V _CE as described above,
For the safe operation of the transistor, for example, T ₁ , it is necessary that its inherent safe operation area is larger than the increasing fluctuation range of the voltage V _CE . That is, in order to maintain the safe operation of each high-speed switching element in the main circuit bridge structure shown in FIG. 3 and to avoid the increase in the capacity of the snubber capacitor as much as possible, the bridge structure is defined by the above-mentioned back electromotive force calculation formula. It is necessary to reduce the stray inductance in each main circuit or snubber circuit.

However, as shown in FIG. 6, in the conventional main circuit bridge structure, each main circuit wiring is made independently according to the main terminal arrangement of each switching device, and each wiring distance tends to be long. Therefore, there is a limit to the reduction of the stray inductance of each main circuit wiring itself, such as 9 and 15 in the figure. Similarly, there is a limit in reducing stray inductance in the snubber wiring.

Therefore, conventionally, there has been no choice but to increase the capacity of the snubber capacitor or adopt a large-capacity transistor in which the safe operation area is expanded in response to the above-mentioned reduction limits of the stray inductances. The power converters such as inverter devices have become larger and more expensive. In view of the above, the present invention aims to reduce the stray inductance in each circuit wiring by reducing the distance between the main circuit wiring and the snubber wiring by changing the module arrangement in the main circuit configuration by the modularized high-speed switching device. An object of the present invention is to provide a method for configuring a main circuit of a high speed switching device.

[0013]

In order to achieve the above object, in the method for constructing a main circuit of a high speed switching device according to the present invention, 1) the invention of claim 1 has a pair of complementary structures in which respective main electrode arrangements are different from each other. Inverter device in which the semiconductor switching device is used as upper and lower arm elements for one phase in the main circuit bridge structure, and a snubber capacitor is connected between the positive and negative main electrodes of the pair of devices connected to the positive and negative power supply buses. In these cases, the two devices are arranged adjacent to each other so that the distance between the main electrodes connected to each other between the pair of devices is the shortest, and the main electrodes of both the devices connected to each other in the bridge configuration. The shortest wiring distance between them, and from the DC power supply of the inverter device to the input main electrode of both devices The wirings of both positive and negative power supply bus lines shall be arranged as close as possible and arranged in parallel.

2) A second aspect of the present invention is a method for constructing a main circuit of a high speed switching device according to the first aspect,
The wiring distance of the snubber capacitor connected between the positive and negative main electrodes of the pair of semiconductor switching devices shall be the shortest. 3) According to the invention of claim 3, the pair of complementary upper and lower arm elements for the main phase of the main circuit bridge structure of the inverter device are provided by wiring between the main electrodes according to claim 1 and the snubber wiring according to claim 2. The present invention relates to parallel connection of a plurality of paired devices each having a switching device having a structure as a unit configuration, and connecting the upper and lower arm connection points of the plurality of paired devices to each other to form a common output wiring to a load, and A plurality of pairs of devices are connected in parallel at both positive and negative power supply buses of the DC power source of the inverter device, and the wiring distance for parallel connection between the positive and negative power supply buses and each device main electrode is made equal and shortest. And

[0015]

[Function] Generally, the self-inductance of a conductor forming an electric path (and hence the stray inductance of a circuit wiring conductor)
Is the amount of magnetic flux generated by the unit current flowing through this electric path,
That is, it is proportional to the rate of change of the amount of magnetic flux with respect to the current and also to the conductor length. Further, when currents of equal size and opposite current directions are made to flow through closely parallel two conductors of the same length, the magnetic fluxes formed by the two conductors cancel each other out and the total magnetic flux amount by both conductors is zero. Alternatively, it becomes almost zero.
Therefore, the total self-inductance of the parallel two conductors is also zero or substantially zero.

According to the above, the present invention relates to: 1) a main circuit bridge structure of an inverter device or the like in which a pair of switching devices having a complementary structure are formed as upper and lower arm elements for one phase as in the invention of claim 1; By arranging these devices adjacent to each other so that the distance between the corresponding electrodes of the device that forms the device is the shortest, the stray inductance in the wiring between the main electrodes is reduced, and the positive and negative poles from the DC power supply to the main circuit bridge are further reduced. By arranging the power supply busbars as close to each other as possible in parallel, it is intended to reduce the stray inductance in the positive and negative bipolar power supply busbars.

2) According to the invention of claim 2, claim 1
In addition to the inter-main-electrode wiring method described above, the snubber wiring connecting the main electrodes of the paired devices is shortened to reduce stray inductance in the snubber wiring. 3) According to the invention of claim 3, a parallel connection of a plurality of pairs of devices, each unit of which is a pair of switching devices having a complementary structure, in which the wiring between main electrodes according to claim 1 and the snubber wiring according to claim 2 are made. Yes, the upper and lower arm connection points of each of the plurality of pairs of devices are connected to each other to form a common output wiring to a load, and the plurality of pairs of devices are connected in parallel on both positive and negative power supply buses of the inverter unit DC power supply. In addition to the connection, the wiring distances for parallel connection between the positive and negative power supply buses and the device main electrodes are made equal and shortest.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the main circuit configuration diagrams shown in FIGS. 1 shows a first embodiment of the present invention corresponding to claims 1 and 2, and FIG.
The main circuit diagram of FIG. 2 shows a second embodiment of the present invention corresponding to claims 2 and 3, and FIG.
The main circuit diagram of FIG.

First, FIG. 1 is a main circuit configuration diagram of the upper and lower arm elements for one phase in the main circuit bridge configuration of the single-phase inverter shown in FIG.
The whole of the main circuit bridge is constituted by a set. In FIG. 1, 1 and 2 are combinations (T ₁ -D ₁ ) and (T ₁ -D ₁ ) of the transistor and the diode shown in FIG. 3, respectively.
_2- D ₂ ) are housed, and both have a complementary structure in which the main terminals of the collector (C) and the emitter (E) of the housed transistor are different from each other. Incidentally, B in the figure is a base terminal of the transistor. Further, 5 is a power source capacitor which is composed of a plurality of unit capacitors and functions as a DC power source, and 6 is a snubber capacitor provided between the main electrodes of the transistors T ₁ and T ₂ .

Now, if the modules 1 and 2 are closely arranged as shown in FIG. 1 according to the connection state shown in the main circuit diagram of FIG. 3, the emitter (E) of the transistor T ₁ and the transistor T ₂ are The distance between the collectors (C) becomes the shortest, and the stray inductance 15 of the wiring between both main terminals becomes extremely small. Further, the distance between the collector (C) of the transistor T ₁ and the emitter (E) of the transistor T ₂ is also the shortest, and the required wiring length of the snubber capacitor 6 connected between them is also the shortest, and the stray inductance of this wiring path is short. 10 is also the minimum.

Further, a feed bus connecting the collector (C) of the transistor T ₁ and the positive bus of the capacitor 5,
By arranging the feed bus connecting the emitter (E) of the transistor T ₂ and the negative bus of the capacitor 5 as close as possible to each other in parallel, the stray inductance 9 in both the feed buses is zero or a minimum value close to zero. You can Note that, in FIG. 1, the symbol ¬ cross-displayed on both of the power supply buses indicates the close parallel arrangement of these two power buses.

Next, FIG. 2 is a main circuit configuration diagram of one phase upper and lower arm elements in the main circuit bridge configuration of the single-phase inverter shown in the main circuit diagram of FIG. Note that, in FIG. 4, in order to increase the output capacity of the single-phase inverter shown in FIG. 3, two pairs of upper and lower arm elements of each phase of the main circuit bridge configuration having a complementary structure are connected in parallel for each arm element. It shows the state of being done.

Here, in FIG. 4, a combination of modules 11 and 21, and a snubber capacitor 61, a module 12 and 22, and a snubber capacitor 62.
The combination consisting of and is to form the upper and lower arm elements for one phase of the main circuit bridge configuration, respectively, the connection points between the respective upper and lower arms are connected to each other and are connected in parallel to each of the upper and lower arms, As described above, the upper and lower arm groups 100 for one phase of the bridge structure are formed, and this arm group 100 corresponds to the upper and lower arm elements for one phase consisting of the module 1 and 2, and the snubber capacitor 6 shown in FIG. However, the capacity is increased.

The stray inductances 31 and 32, 51 and 52 of the wirings shown in FIG. 4 are the stray inductances 9 shown in FIG. 3 distributed and displayed for each wiring. Similarly, the inductances 41 and 42 are the same. This corresponds to the stray inductance 15 shown in FIG. A portion 200 surrounded by a one-dot chain line in the drawing is a group of upper and lower arms having the same circuit configuration as that of the portion 100.
00 and 200 form a main circuit bridge of the single-phase inverter whose output capacity is increased.

Therefore, FIG. 2 shows the above-mentioned upper and lower arm group 10
0 is a main circuit configuration diagram corresponding to 0, and the power transistor module 1 closely arranged as shown in FIG. 1 according to FIG.
One more combination of 1 and 2 is added and closely arranged. That is, as shown in FIG. 2, the emitters (E) of the modules 11 and 12 and the collectors (C) of the modules 21 and 22 that are the connection points between the upper and lower arms.
And are connected to each other to form a common output wiring to the load 8,
Further, regarding the two sets of positive and negative bipolar power supply busses extending from both module groups forming a pair of the modules 11 and 21, 12 and 22 to the positive and negative power supply busbars of the capacitor 5 for power supply, the required wiring distances of both are equal to each other and the shortest. As well as
In each set, the positive and negative bipolar busbars are closely arranged in parallel.

As described above, in the circuit configuration shown in FIG. 2, as in the case of FIG. 1, the stray inductances 31 and 32, 51 and 5 in the two sets of positive and negative bipolar feeder buses are used.
2 is equal to and is the minimum. In addition, the stray inductances 41 and 42 of the wiring for connecting the upper and lower arms
And the stray inductance of the snubber wiring (not shown) can be made extremely small, the reduction of the counter electromotive voltage during the switching operation according to the main circuit diagram of FIG. Equilibrium can be avoided.

[0027]

According to the present invention, there is provided a main circuit bridge structure such as an inverter device in which a pair of switching devices having a complementary structure are formed as upper and lower arm elements for one phase. By arranging these two devices adjacent to each other so that the distance between the electrodes corresponding to each connection of the device is made the shortest, and by arranging the positive and negative bipolar feed buses extending from the DC power supply to the main circuit bridge as close to each other as possible, By reducing the stray inductance between the wiring between the main electrodes of each device and the positive and negative bipolar feed bus, and by reducing the stray inductance by shortening the snubber wiring between the main electrodes of both devices as claimed in claim 2. And also
According to the invention of claim 3, a plurality of pair devices are connected in parallel in a unit configuration of a pair of switching devices having a complementary structure in which the inter-main electrode wiring according to claim 1 and the snubber wiring according to claim 2 are formed. The pair of devices are connected in parallel at both positive and negative power source bus lines of the DC power source of the apparatus, and the wiring distance for parallel connection between the positive and negative power source bus lines and each device main electrode is made equal and shortest to each other. It is possible to reduce the stray inductance in each of the parallel connection wirings that also serve as a power supply busbar. Therefore, the reduction of the wiring stray inductance in any of the above cases enables the switching operation of the main circuit bridge, especially each switching device. It becomes possible to effectively suppress the back electromotive force generated at the turn-off of the For the high-speed switching devices and the like, can when to perform the operation at its original switching speed without the need for expansion of its safe operating area,
Further, since it is unnecessary to increase the capacity of the snubber capacitor that absorbs the counter electromotive voltage, it is possible to improve the performance and reduce the size and cost by increasing the operating frequency of the power conversion device such as the inverter device.

[Brief description of drawings]

FIG. 1 is a main circuit configuration diagram of a transistor module showing a first embodiment of the present invention.

FIG. 2 is a main circuit configuration diagram of a transistor module showing a second embodiment of the present invention.

FIG. 3 is a main circuit diagram showing a basic circuit configuration of a single-phase inverter.

FIG. 4 is a main circuit diagram showing a basic circuit configuration of a single-phase inverter (when two arm elements are connected in parallel).

FIG. 5 is an operation waveform diagram of a back electromotive force at device turn-off.

FIG. 6 is a main circuit configuration diagram of a transistor module showing an example of a conventional technique.

FIG. 7 is a perspective view of a transistor module configuration corresponding to FIG.

[Explanation of symbols]

1-4 power transistor module 5 power supply capacitor 6,7 snubber capacitor 8 load 9,15 stray inductance of main circuit wiring 10 stray inductance of snubber wiring 11,12 power transistor module 21,22 power transistor module 31,32 main circuit wiring Stray inductance 41,42 Main circuit wiring stray inductance 51,52 Main circuit wiring stray inductance 61,62 Snubber capacitor 100 Main circuit bridge configuration upper and lower arm group 200 Main circuit bridge configuration upper and lower arm group B Base terminal C Collector terminal D diode (D ₁ ~D ₄₎ E emitter terminal T the power transistor (T ₁ through T ₄₎

Claims (3)

[Claims] 1. A pair of complementary structure semiconductor switching devices, each having a different main electrode arrangement, are used as upper and lower arm elements for one phase in the main circuit bridge structure, and are connected to both positive and negative power supply buses. In an inverter device in which a snubber capacitor is connected between the positive and negative main electrodes of the device, these devices are arranged adjacent to each other so that the distance between the main electrodes mutually connected between the pair of devices is the shortest. In the configuration of the bridge, the wiring distance between the main electrodes of the two devices connected to each other can be minimized, and the wiring of the positive and negative power source buses from the DC power source of the inverter device to the input main electrodes of the two devices can be performed. A method for constructing a main circuit of a high-speed switching device, which is characterized in that they are arranged close to each other and arranged in parallel. 2. The method for configuring a main circuit of a high speed switching device according to claim 1, wherein the wiring distance of the snubber capacitor connected between the positive and negative main electrodes of the pair of semiconductor switching devices is set to the shortest. Main circuit configuration method for high-speed switching device. 3. A pair of switching devices having a complementary structure, in which the wiring between the main electrodes according to claim 1 and the snubber wiring according to claim 2 are formed to constitute upper and lower arm elements for one phase in the main circuit bridge configuration of the inverter device. Relating to parallel connection of a plurality of paired devices each having a unit configuration, and connecting upper and lower arm connection points of each of these plurality of paired devices to each other to form a common output wiring to a load, and Inverter device High-speed switching characterized by being connected in parallel at both positive and negative power supply buses of the DC power supply, and making the wiring distance for parallel connection between the positive and negative power supply buses and each device main electrode equal to each other and shortest Device main circuit configuration method.