JPS5944978A - Inverter device - Google Patents

Abstract

PURPOSE:To reduce the loss of a snubber circuit by feeding back the energy of a snubber condenser to a power source side. CONSTITUTION:When GTOs 2, 8 are turned OFF and GTOs 4, 6 are turned ON, a load current flows through condensers 42, the GTO6, a load 10, the GTO4 and condensers 44, 42. Then, when the GTOs 2, 8 are turned ON and the GTOs 4, 6 are turned OFF, a load current flows through a condenser 42, the GTO2, the load 10, the GTO8 and the condensers 44, 42. When the switch elements 52, 58 are turned ON, a vibrator which has a snubber condenser 22, the condenser 42, a reactor 46 and the switch element 52, and a vibration which has a snubber condenser 28, the switch element 58, a reactor 48, a condenser 44 are formed, and the energies of the condensers 22, 28 are respectively fed back to the condensers 42, 44.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inverter device comprising a self-extinguishing switching element, and more particularly to an inverter device suitable for reducing loss in a snubber circuit connected in parallel to the above-mentioned switching elements. .

Self-extinguishing switching elements such as transistors and gate turn-off thyristors are usually connected in parallel with a nanocircuit in order to absorb the voltage applied during turn-off. Snubber episode ii! In general, the capacitor includes a capacitor and a resistor, and this capacitor is charged to a low level when the switching element is turned off, and is discharged through the resistor when the switching element is turned on.Therefore, the switching element is turned on and off. Then, a loss occurs in the snubber circuit (most of the loss is heat loss in the resistance Q').

When the inverter device is configured with such self-extinguishing switching elements in the snubber circuit 4q, snubber circuit loss inevitably occurs during its operation.

Naturally, as the inverter drive frequency increases, the snapper circuit loss also increases.

Therefore, an object of the present invention is to provide an inverter device with extremely low snubber circuit loss.

The main points of the present invention are to remove the resistor from the snubber circuit, and to use the energy stored in the snubber capacitor to create a new snubber capacitor and a resonance circuit with the accelerator! 3'f
: It is located at the point where it is used and returned to the power source. The present invention will be described in detail below with reference to Examples. For convenience of explanation, a gate turn-off thyristor (hereinafter abbreviated as GTO) will be taken as an example of a self-extinguishing switching element, but the present invention is not limited to GTO.

FIG. 1 shows an embodiment in which the present invention is applied to a single-phase inverter. As shown in the figure, there is a G between 10 DC power supplies and both city poles.
The group that played T O2 and GTO4 directly in late January, and the GT
O6 and GTO8 are connected in series, /ζ+lJj is connected, and the connection point of GTO2 and GTO4 is connected to OT 06 and GTO.
A load 10 is connected between the connection point 8 and the connection point 8. Each GTO
2, 4, 6, and 8 have diodes 1) and 12.
14, 16, and 18 are connected in antiparallel, respectively (freewheeling diodes are necessary for voltage source inverters, and are unnecessary for current source inverters), and snubber capacitors 22, 24 are connected, respectively.
, 26.28 and the series connection ports of diodes 32, 34, 36.38 are connected in antiparallel, respectively. On the other hand, a first capacitor 42 and a second capacitor 44 are connected in series between the two poles of the DC power source 1 . This capacitor 42゜4
4 is always charged by the DC power supply 1 and functions as a power source for the inverter. If the voltage value of the DC power supply 1 is iE, each capacitor 42.44 is divided into voltages fiEj F, /2.

The connection points of the capacitors 42 and 44 and the connection points of the snubber capacitor and the diode are connected to the reactor 46.
．． 48 and switch element (SW) 52゜54.56.58
are connected to each other via.

FIG. 2 is an explanation (9) of the operation of the inverter shown in FIG. 1.

As shown in the figure, ()T02 and GTO8 are turned on and off at the same time, and GTO4 and GTO6 are turned on and off in the opposite direction. After a short time has passed after these GTOs are turned on, 5W5
2.58 and 54.56 are turned on, respectively. This is to return the energy stored in the snubber capacitor to the source.

The method of return will be explained in detail below.

First, at time 11 in Figure 2, GTO2 and 8 are off TGTO
4 and 6 are in the on state. At this time, the load current is r42
-6-10-4-44-424. Prior to this time 11, GTO2 and 8 are turned off, and GTO4,
Time t when 6 was turned on. Immediately after, current flows into the snubber circuit of GTO2 and 8 through the r42-22-32-4-44-42J path and the 42-6-38-2s-44-42J path, and the snubber capacitor 22° 28 are charged to the polarity shown in the figure.When GTO2 and 8 are turned on and GTO4 and 6 are turned off at time t2, the load current becomes l'-4.
It flows along the route 2-2-10-8-44-42J. At this time, the snubber capacitor 22.28 does not discharge on its own. However, when turning on 5W52.58 at time 13, 2
Two vibration circuits 1'-22-42-46-52-22J and l'-28-58-48-44-28 are formed,
Snubber condensate? The energy of 22°28 is condens'v+-42 respectively.

It will be returned in 44th. If a thyristor is used as 5W52.58, the time t4 when the snubber capacitor releases
5W52,58ili turns off by itself. This operation is similar when the snubber capacitors 24 and 26 are released 111:.

FIG. 3 shows an embodiment in which the present invention is applied to a full three-phase inverter. In the figures, the same reference numerals as in FIG. 1 indicate the same parts.

Blocks 64 and ' 6 G are respectively dashed block 6
2), the outputs of each block 62, 64, and 6 are connected to three-phase loads 101, 102, and 103, respectively. Also, the light spot on the tangent of Conf. 42.44 is,
They are connected to blocks fi2, 64 and 66 via reactors 49, respectively. The operation is similar to that shown in FIG. 1, so a description thereof will be omitted.

As described above, according to the present invention, since the energy of the snubber capacitor is returned to the '1'i:C source side, it is possible to obtain an inverter device with extremely low snubber circuit loss.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment in which the present invention is applied to a single-phase inverter, Fig. 2 is an explanatory diagram of the operation of Fig. 1, and Fig. 3 is a diagram showing an embodiment in which the present invention is applied to a three-phase inverter. ].

Claims (1)

[Scope of Claims] 1. An inverter device in which at least one set of self-extinguishing switching elements is connected in series between both electrodes of a DC power source, and an output is obtained from the series connection point. A series connection between the two electrodes of the power supply, a series connection of a snubber capacitor and a diode connected in parallel to each of the self-extinguishing type control elements, a connection point between the first capacitor and the second capacitor, and the connection point between the first capacitor and the second capacitor and the above. An inverter device comprising a series connection body of a reactor and a switch element connected between each connection point of a snubber capacitor and a diode. 2. The inverter device according to claim 1, wherein the self-extinguishing switching element is a gate turn-off thyristor. 3. The inverter device according to claim 1 or 2, wherein the switching element is a thyristor.