JP2001128467A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that with a main circuit wiring mounted with low inductance, influence of the wiring inductance in a semiconductor module on the output voltage of an inverter is increased, that is, output three-phase voltage waveform is varied according to differences in wiring inductance in phases U, V, and W in the semiconductor module. SOLUTION: In a semiconductor module, having two or more pairs of P terminals and N terminals, a flat conductor connecting the positive-side terminals and a flat conductor connecting the negative-side terminals are used to mount a laminated wiring structure where insulators are sandwiched between the two flat conductors. Thanks to this laminated wiring structure, the wiring inductance up to three-phase output terminals, as seen from the P terminal and N terminal side is smoothed and reduced, and variation in jump-up voltage waveform during switching is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter, and more particularly to a technique for mounting a main circuit conductor of a power conversion semiconductor module constituting a main circuit of the power converter.

[0002]

2. Description of the Related Art In a power converter, main circuit wiring of a forward converter and an inverse converter is constituted by bus bar (conductor plate) wiring or cable wiring. A smoothing capacitor is arranged on the main circuit wiring to the forward converter and the inverse converter to smooth the output of the forward converter. When the inductance of the wiring connecting the smoothing capacitor and the inverter is large, the jump voltage at the time of switching of the inverter circuit becomes large, and element destruction or the like may occur. In order to prevent such an increase in the jumping voltage, recently, the + side wiring and the − side wiring of the main wiring have a flat plate laminated structure, and the jumping voltage is suppressed by reducing the wiring inductance. This prior art is disclosed in
There is one described in -225545. This technique is a method of reducing wiring inductance by arranging two bus bar wirings through which a reciprocating current flows in close proximity.
In addition, the above-described wiring inductance reduction technology by the wiring flat plate laminated structure is also applied to a wiring structure for connecting a power converter switch element in a converter. As this technique, there are those described in JP-A-6-69415 and JP-A-8-140363.

Further, in a system in which a power converter and a motor are combined, a current flows through a ground line of the motor or the like due to an imbalance in current and voltage between three-phase wires for supplying power to the motor and the like. The above current (hereinafter referred to as leakage current) includes a noise current having a high frequency component. As a conventional technology for suppressing the leakage current, an inductance filter is mounted on a ground line to cut off a current in a high frequency region. Measures have been taken.

[0004]

SUMMARY OF THE INVENTION In power converter wiring,
In particular, when the inductance of the wiring connecting the smoothing capacitor and the inverter with a large amount of current is large, the jump voltage at the time of switching of the inverter circuit becomes large, causing problems such as element destruction and power loss. With respect to this problem, the main circuit wiring inductance is becoming almost equal to the wiring inductance in the power conversion semiconductor module used for the inverter by the main circuit wiring laminated conductor plate mounting method described in the related art. Due to the reduction in the main circuit wiring inductance, the influence of the inductance of the wiring connecting the switch elements in the power conversion semiconductor module on the switching waveform of the power conversion semiconductor module has increased.
Therefore, a difference occurs in the three-phase output voltage waveform according to a difference in wiring inductance to each phase in the module. This difference in the three-phase output voltage waveform is one of the causes of the current-voltage imbalance between the three-phase wiring. In a system in which a power converter and an electric motor are combined, the three-phase wiring A high-frequency common mode current flows through a cable, and a high-frequency leakage current flows through a ground wire such as an electric motor. The wiring structure in the power conversion semiconductor module is supported by the low inductance technology as described in the related art.

An object of the present invention is to further improve the solution to the above-mentioned problem, and to smooth and reduce the wiring inductance from the P terminal and the N terminal to the three-phase output terminal, that is, at the time of switching. It is an object of the present invention to provide a power converter that suppresses a variation in the voltage waveform of a jump.

[0006]

An object of the present invention is to provide a plurality of +
For a power converter module having a negative terminal (P terminal) and a negative terminal (N terminal),
This is achieved by changing the geometric structure of the wiring connected to the terminal and the N terminal and the terminal connection structure. Specifically, as an external wiring of a power conversion semiconductor module having two or more pairs of a + side terminal (P terminal) and a − side terminal (N terminal), a flat conductor connecting between the + side terminals and a − side terminal. This is achieved by forming a laminated structure in which an insulator is interposed between the two flat conductors. According to the present invention, by connecting a low-inductance wiring between the same-polarity terminals of the semiconductor module from the outside, the inductance seen from a plurality of semiconductor module terminals is reduced and equalization is achieved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power converter comprises a forward converter (including a diode) for converting AC input power to DC, a smoothing capacitor for smoothing the output of the forward converter, and a variable voltage / variable frequency for the DC. A main circuit that connects each electrical component such as an inverse converter that converts power to the control device, a control unit that drives and controls these converters, and a cooling body that cools these electrical components (a cooling fin, a cooling fan, a wind tunnel, etc.) Body).

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7, the same components and components having the same functions are denoted by the same reference numerals.

FIG. 5 shows a circuit configuration of a minimum necessary power converter. In FIG. 5, 1 is a three-phase AC power supply,
2 is an input wire, 3 is a forward converter, 4 is a main circuit wiring, 4a is a P-side wiring of the main circuit wiring, 4b is an N-side wiring of the main circuit wiring,
5 is a smoothing capacitor, 6 is an inverter module, 7 is an output wiring, and 8 is an induction motor (also called a load).
The forward converter 3 is composed of a variable control element such as an IPM or a power semiconductor. The forward converter 3 converts the three-phase AC power supply 1 into DC and, when the DC-side voltage exceeds a predetermined value, the three-phase AC power supply. The power generated on the load side is regenerated on one side. When the power generated on the load side is not regenerated to the three-phase AC power supply 1,
In many cases, a diode module that performs full-wave rectification is used instead of the forward converter 3. The present invention relates to the forward converter 3
Alternatively, the diode module may be used.
The inverter 6 is composed of an IPM that converts the DC voltage smoothed by the smoothing capacitor 5 into a variable voltage and a variable frequency. Although not shown in the circuit diagram, in addition to the components described above, the power converter includes an initial charging current suppression resistor for suppressing a large current flowing to the smoothing capacitor 5 at the initial stage of power-on, and an initial after charging of the smoothing capacitor 5. It is composed of an electromagnetic contactor for short-circuiting a charging current suppression resistor, a heating element such as the forward converter 3 and the reverse converter 6, a cooling fin for cooling a module, a cooling fan, and the like.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a P-terminal 9a and a P-terminal 9b in a semiconductor module (IPM11) having two pairs of a + terminal (P terminal) and a-terminal (N terminal) operating as an inverse converter.
The flat conductor 15, the N terminal 10a, and the N terminal 10
3A shows a laminated structure of a flat conductor 16 connecting between b and an insulating sheet 17 sandwiched between the flat conductors 15 and 16.

FIG. 2 is a diagram showing the lamination relationship of the P-side plate conductor 15, the N-side plate conductor 16, and the insulating sheet 17 of FIG. This insulating sheet 17 electrically insulates the P-side conductor plate 15 and the N-side conductor plate 16. However, in the present invention, P
Even if the side plate conductor 15 is arranged on the N-side plate conductor 16 with the insulating sheet 17 interposed therebetween, the same effect can be obtained. The flat conductor of the present invention is bent to match the terminal position and height of the IPM 11.

FIG. 3 shows the wiring inductance inside the semiconductor module. As can be seen from FIG. 3, the wiring inductance is different due to the difference in the path from the right PN terminal to the UVW phase output terminal. The inductance from the left PN terminal to the UVW phase output terminal is also different. In order to clarify the problems of the conventional system and the effects of the present invention, the above-mentioned PN terminal is used to output UVW each phase output terminal U terminal
2, the wiring inductance to the V terminal 13 and the W terminal 14 is roughly calculated. In FIG. 3, the distance between the left and right P terminals is 12 cm.
The width of the PN wiring in the module is 5 mm, and the wiring between the left and right P terminals is P terminal (left) -U terminal-V terminal-W terminal-
When divided into 2: 1: 1: 2 between P terminals (right), 20 nH between P terminal (left) and U terminal, 10 nH between U terminal and V terminal, 10 nH between V terminal and W terminal, W terminal −P
20 nH between terminals (right side). The same approximate value is obtained for the N-side wiring inductance in the module. From the above calculation, the inductance from the left PN terminal to the U-phase output terminal is about twice the inductance to the W-phase output terminal. The difference in inductance causes a difference in the UVW phase output voltage waveform. The right P terminal and the left P terminal of this semiconductor module are connected by two conductor flat plates in which the right N terminal and the left N terminal are stacked as shown in FIG. The inductance of the conductor plate can be reduced by the laminated structure, and the inductance of the conductor plate is estimated to be 20 nH when the dimensions are adjusted to the module used in the above calculation.

As shown in FIG. 3, by connecting the laminated flat plates, the wiring inductance of the conductive flat plate is reduced to the right and left PN.
When the wiring connecting the smoothing capacitor and the inverter is connected to either the left or right PN terminal of the inverter, each circuit from the PN terminal to the UVW phase output terminal is connected in parallel to the circuit viewed from the terminal. Inductance can be smoothed.

FIG. 4 shows the effect of the present invention. FIG. 4 is a graph comparing the jump voltage at the time of switching applied to each UVW phase terminal depending on the presence or absence of the laminated conductor flat plate according to the present invention when the wiring connected to the smoothing capacitor is connected to the left PN terminal of the semiconductor module of FIG. It is. The case where there is is the present invention, and the case where there is no is a comparative example. From FIG. 4, it can be seen that the jumping voltage of the UVW phase voltage is reduced and smoothed by the wiring structure of the embodiment of the present invention, and the variation in the circuit operation of each phase of the UVW is suppressed. In the embodiment of the present invention, the low inductance wiring is connected between the same polarity terminals of the semiconductor module to parallelize the wiring inductance in the semiconductor module, thereby reducing and equalizing the wiring inductance from each terminal. I have. Further, the IPM using the stacked wiring structure of the embodiment of the present invention as a forward converter has the same effect on the input RST phase voltage of the forward converter.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 6 shows the P-side flat conductor and the N-side flat conductor of the present invention, wherein the P-side wiring 18 and the N-side wiring 19 of the main circuit wiring connecting the smoothing capacitor 5 and the inverter (IPM11) are each a P-side flat plate. The structure in which the conductor 15 and the N-side plate conductor 16 are integrated is shown. This P-side plate conductor 15, P
Although not shown, there is an insulator between the side wiring 18 and the N-side flat conductor 16 and the N-side flat wiring 19, and the P-side flat conductor and the N-side flat conductor are electrically insulated. IP
M11 is disposed on the cooling fin 21 and the gate circuit board 2
For 0, a circuit for sending a gate signal to the IPM is mounted. This embodiment has the same effect as the first embodiment, and has an advantage that the number of parts can be reduced as compared with the first embodiment. Further, the laminated wiring structure of this embodiment has the same effect even when a two-layer printed circuit board is used. Further, when the P-side flat conductor 15, the P-side wiring 18, the N-side flat conductor 16, the N-side wiring 19, and the gate circuit are formed on the same substrate by a multilayer printed circuit board, the number of parts and the number of assembly steps can be further reduced. There are advantages.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 7 shows a circuit structure in which the auxiliary capacitor 22 is connected between PN terminals other than the PN terminal to which the main circuit wiring is connected. In this embodiment, the wiring connecting the PN terminal and the auxiliary capacitor 22 is formed by stacking the P-side wiring and the N-side wiring in the same manner as in the first embodiment, thereby reducing the wiring inductance. FIG.
In the second embodiment, the same effect as in the first embodiment can be obtained by causing a current to flow from the auxiliary capacitor 22 to the semiconductor element in the IPM 11 at the time of switching. In the above-described first to third embodiments, the IPM has two pairs of PN terminals. However, even when there are two or more PN terminals, the P-terminal and the N-terminal have a laminated structure. If the connection is made by a flat plate conductor, it is effective to equalize and reduce the jump voltage of each phase of UVW as in the first embodiment. In addition, the insulator sandwiched between the two conductor flat plates in the first and second embodiments is intended only for electrical insulation of the two conductor flat plates, and may be replaced with air.

[0017]

According to the present invention, the variation in the circuit operation of each phase of the UVW, which is one of the causes of the current-voltage imbalance between the three-phase wirings, is suppressed by equalizing and reducing the jump voltage of the UVW phase voltage. Power conversion device can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a wiring structure for connecting semiconductor module terminals according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a wiring laminated structure according to one embodiment of the present invention.

FIG. 3 is a circuit diagram in consideration of wiring and wiring inductance in a semiconductor module according to an embodiment of the present invention.

FIG. 4 is a diagram comparing the jump voltage at the UVW phase terminal when the present invention is used and when it is not used.

FIG. 5 is a circuit diagram of a power conversion device main circuit unit and a motor according to the first embodiment.

FIG. 6 is a perspective view showing a laminated wiring structure according to one embodiment of the present invention.

FIG. 7 is a circuit diagram showing one embodiment of the present invention.

[Explanation of symbols]

1: three-phase AC power supply, 2: input wire, 3: forward converter, 4:
Main circuit wiring, 4a: P-side wiring of main circuit wiring, 4b: N-side wiring of main circuit wiring, 5: smoothing capacitor, 6: inverter module, 7: output wiring, 8: induction motor, 9a, 9
b ... P terminal, 10a, 10b ... N terminal, 11 ... IPM,
12 U terminal, 13 V terminal, 14 W terminal, 15, 1
6: flat conductor, 17: insulating sheet, 18: P side wiring, 1
9 ... N side wiring, 20 ... Gate circuit board, 21 ... Cooling fin.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiji Komatsu 1070 Ma, Hitachinaka-shi, Ibaraki F-term in Mito Works, Hitachi, Ltd. F-term (reference) 5H007 BB06 CA01 CB05 CC03 CC12 DA06 HA04

Claims (4)

[Claims] 1. A forward converter for rectifying an alternating current to convert it into a direct current voltage, a smoothing capacitor for smoothing an output of the forward converter, and converting a direct current voltage obtained from the smoothing capacitor into an alternating current having a variable frequency. An inverter module, having a laminated structure in which an insulator is sandwiched between a plate conductor connecting between a plurality of + terminals and a plate conductor connecting between a plurality of-terminals of the inverter module. A power converter characterized by the above-mentioned. 2. A forward converter module for rectifying an AC to convert the AC voltage into a DC voltage, a smoothing capacitor for smoothing an output of the forward converter module, and a DC voltage obtained from the smoothing capacitor to an AC having a variable frequency. And a laminated structure in which an insulator is interposed between a flat plate conductor connecting between a plurality of + side terminals and a flat plate conductor connecting between a plurality of -side terminals of the forward converter module. A power converter characterized by the above-mentioned. 3. The power converter according to claim 1, wherein the conductor connecting the smoothing capacitor and the positive terminal of the inverter module and the conductor connecting the negative terminal of the inverter module are formed of flat plates. A power converter, wherein a negative-side conductor flat plate is integrated with a flat-plate conductor connecting between a plurality of + -side terminals of the inverter module and a flat-plate conductor connecting between a plurality of -side terminals. 4. A forward converter for rectifying AC and converting it to a DC voltage, a smoothing capacitor for smoothing the output of the forward converter, and converting a DC voltage obtained from the smoothing capacitor into an AC having a variable frequency. And a positive terminal and a negative terminal connected to the smoothing capacitor of the inverse converter module, the positive terminal and the negative terminal of the inverse converter module being different from each other.
A power converter having a structure in which a capacitor is connected to a side terminal and a negative side terminal.