JPH064154A - Driving power supply for bridge circuit - Google Patents

Abstract

PURPOSE:To decrease the number of driving power supplies by securing the common use of the driving power supply of a common GND of a bridge circuit. CONSTITUTION:The power supply of the driving circuits DC2 and DC4 having a common GND is connected to a common power supply E24. The output lines L2 and L4 of both circuits DC2 and DC4 are twisted and wound round a core having high permeability. At the same time, an inductor is put into a power line and the capacitors are connected in parallel to the driving circuit of each power line. In such a constitution, a common loop current never easily flows in a switching mode of a bridge circuit and the driving power supplies can be integrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving power supply for driving a bridge circuit composed of semiconductor switching elements.

[0002]

2. Description of the Related Art In a parallel-connected bridge circuit using semiconductor switching elements, when a switching operation is performed, even if the GND of the semiconductor switching elements is common, the power source for driving the semiconductor switching elements malfunctions, so all are insulated. I was trying to make it independent. Figure 4 shows I
A conventional specific example using a GBT (insulated gate bipolar transistor) module will be shown.

In FIG. 4, Q1 to Q4 are IGBT modules, and Q1 and Q2, Q3 and Q4 are respectively connected in series, and two of these series-connected ones are connected in parallel to form a bridge. ing. Parallel connection point P
A DC voltage V is applied between 13 and P24, and an output is obtained between the series connection points P12 and P34. DC1 to DC
4 is a drive circuit, each IGBT module Q1 ~
Drive Q4. The control circuits of the drive circuits DC1 to DC4 are omitted.

E1 to E4 are driving power supplies, which are provided in the respective driving circuits DC1 to DC4. D1 to D4 are protective diodes. Further, L1 to L4 are drive circuit output lines of the drive circuits DC1 to DC4, and W1 to W4 are the drive power sources E1 to E4 and the drive circuits DC1 to DC.
4 shows a power supply line connecting with 4. IGBT modules Q1 to Q
4 has a common GND, but the driving power supplies E2 and E4 are independent of each other so as not to malfunction. In the following description, the suffix of each code will not be attached unless it is necessary to distinguish them individually.

[0005]

Conventionally, the driving power source E2 is used.
As described above, E4 and E4 malfunction even if the common GND is used, and thus there is a problem that they cannot be unified.

The present invention has been made to solve the above problems, and an object of the present invention is to unify the driving power sources of the common GND to reduce the driving power sources.

[0007]

In the drive power supply according to the present invention, a drive circuit for each semiconductor switching element on the reference voltage side of a DC voltage is connected to a common power supply, and each drive circuit output line is a twisted wire or a twisted wire. It is a coaxial wire that is brought close to or wound around a high-permeability member. Further, an inductor is inserted in each power supply line, and a capacitor is connected in parallel to the common power supply on the drive circuit side of each power supply line.

[0008]

In the common driving power supply of the present invention, due to the action of the inductance in the drive circuit output line and the power supply line, the common loop current becomes difficult to flow in the case of switching, so that the malfunction is prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
Reference numeral 4 denotes a common power source, and the other parts are the same as those in FIG. Figure 1
Although not shown in FIG. 1, the drive circuit output lines L2 and L4 of this embodiment are configured as shown in FIG. The details of the power supply lines W2 and W4 will be described later.

That is, in FIG. 2, reference numeral 1 is a twisted wire, which is wound around a core 2 having a high magnetic permeability.
5 is the gate of the IGBT module Q2 (or Q4),
Shows emitter and collector.

The operation of the embodiment shown in FIGS. 1 and 2 is as follows. In the common mode, since the core 2 having a high magnetic permeability significantly increases the inductance, it becomes difficult for the common loop current due to switching to flow, and the common power source E24 can be used. In addition, the inductance hardly increases in the normal mode. The drive circuit output lines L2, L
Instead of the twisted wire 1, 4 may be a coaxial wire. Further, a member having a high magnetic permeability such as the core 2 may be arranged in close proximity without being wound around the core 2.

FIG. 3 shows the power supply line W of the embodiment of the present invention shown in FIG.
2 is a circuit diagram of a portion W2. FIG. In FIG. 3, the power supply line W
An inductance 11 is inserted in each of W2 and W4, and a capacitor 12 is provided on the drive circuit DC2, DC4 side.
Are connected in parallel to the common power source E24. Reference numerals 13 and 14 denote power supply terminals.

The operation of the circuit of FIG. 3 is as follows. The power supply terminals 13 and 14 of the circuit shown in FIG. 3 are connected to the drive circuits DC2 and IGBT2 of the IGBT modules Q2 and Q4 whose GND side is common.
When connecting to DC4 and performing a switching operation, since the inductance 11 is in series with the common loop, it becomes difficult for a common loop current with a high frequency component to flow,
A common power supply E24 can be used.

[0014]

As described above, according to the present invention, the drive circuit of each semiconductor switching element on the reference voltage side of the DC voltage is connected to the common power source, and each drive circuit output line is formed as a twist line or a coaxial line. Since the high-permeability member is placed close to or wrapped around, the inductor is inserted in each power supply line, and the capacitor is connected in parallel to the common power supply on the drive circuit side of each power supply line. The common loop current is less likely to flow during switching from either the drive side or the drive circuit output line side, so that the drive power supply can be shared, and the number of power supplies can be reduced by sharing the drive power supply. There is.

[Brief description of drawings]

FIG. 1 is an overall circuit diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing details of a main part of FIG.

FIG. 3 is a circuit diagram showing details of another main part of FIG.

FIG. 4 is a circuit diagram showing a driving power supply for a conventional bridge circuit.

[Explanation of symbols]

 1 twisted wire (or coaxial wire) 2 core with high magnetic permeability 3 gate 4 emitter 5 collector 11 inductance 12 capacitor 13 power supply terminal 14 power supply terminal DC drive circuit E power supply Q IGBT module L2 drive circuit output line L4 drive circuit output line W2 power line W4 power line

Claims (1)

[Claims] 1. Two sets of semiconductor switching elements each having a drive circuit connected in series are connected in parallel, and a DC voltage is applied between the parallel connection points to obtain an output between the series connection points. In the drive power supply used for the drive circuit of the bridge circuit, the drive circuit of each semiconductor switching element on the reference voltage side of the DC voltage is connected to a common power supply, and each drive circuit output line is a twisted line or a coaxial line It is characterized in that it is placed close to or wound around a high magnetic permeability member, an inductor is inserted in each power supply line, and a capacitor is connected in parallel to the common power supply on the drive circuit side of each power supply line. Power supply for driving the bridge circuit.