RU107419U1 - IGBT DRIVER - Google Patents

Abstract

 An IGBT driver containing an input galvanically isolated control circuit, an intermediate amplifier, and output gate current conditioners IGBT, characterized in that a symmetrical voltage amplifier is introduced into the oncoming current sources, an integrating capacitor, normalizing the rate of change of the output voltage, a push-pull emitter repeater at the output, flowing in and leakage currents of which are limited by resistors in the emitters of transistors, and Schottky diodes, limiting the amplitudes of the induced voltage pulses at the output drivers at driver voltage levels.

Description

The utility model relates to electrical engineering, in particular, to converter technology, and can be used as an IGBT driver.

Known driver circuits [1], which include an optocoupler, a voltage amplifier on a transistor with a resistor as a load, and a push-pull emitter follower (Figure 1).

The disadvantages of such schemes are asymmetric operation of the amplifier at a high and low voltage pulse level, the abnormal rate of voltage change during rise and fall of the pulse, the lack of limitation of the amplitude of the current pulse at the driver output, the possibility of induced voltage pulses at the driver output, which are dangerous for the IGBT gate.

Objectives of the utility model: to balance the amplifier, normalize the rate of change of voltage, limit the amplitude of the output current pulse, limit the amplitude of the induced voltage pulses at the driver output to a safe level.

Figure 2 presents a diagram of the proposed driver.

The driver contains an optocoupler or an optical receiver 1, a capacitor 2, resistors 3 ... 9, resistors 10 and 11, Schottky diodes 12 and 13, transistors 14 ... 19.

The driver works as follows:

The current flowing through the resistor 5 and the stabilizers 10, 11, creates on the bases of the transistors 14 and 15 unlocking voltage. Thanks to the resistors 3 and 4 connected to the emitters and power sources + U and -U, the collector currents of the transistors are stabilized, that is, counter current sources are obtained. The states of the transistors are switched by the optical receiver 1 and auxiliary transistors 16 and 17. In the initial mode, the optical transistor is locked, the transistors 15, 17 and 16 are turned on, and the transistor 14 is turned off. At the output of driver G, the voltage is negative with respect to terminal E. When a control pulse is applied to the optical detector 1, its transistor turns on, and transistors 15, 17, 16 turn off, and transistor 14 turns on. The capacitor 2 is charged with a stable current almost to the voltage level + U, that is, the capacitor performs the function of an integrator. The voltage at the bases of transistors 18, 19 of the emitter follower increases linearly. The output voltage of the driver also rises, the current of the transistor 18 (leaky) is limited by the resistor 8. After the end of the control pulse, the driver returns to its original mode, the capacitor 2 is discharged with a stable current almost to the voltage level -U. The voltage at the bases of transistors 18, 19 decreases linearly. The output voltage of the driver also decreases, the current of the transistor 19 (flowing) is limited by a resistor 9. Diodes 12 and 13 limit the amplitude of the induced voltage pulses almost at the levels + U and -U, respectively.

Thus, the proposed driver has a symmetric amplifier for low and high voltage levels, constant voltage rise and fall rates, independent levels of limiting the amplitude of the outgoing and incoming currents, limits the amplitudes of the induced voltage pulses at the driver output to safe levels.

Information sources:

1. Power Mitsubishi - Hybrid driver circuits for IGBT

Claims (1)

Driver IGBT, having an input galvanically isolated control circuit, an intermediate amplifier and the output driver currents IGBT gate, characterized in that it introduced symmetrical amplifier voltage at the counter current source, integrating capacitor, normalizing the rate of change of the output voltage, push-pull emitter follower output, influent and the leakage currents of which are limited by resistors in the emitters of transistors, and Schottky diodes, limiting the amplitudes of the induced voltage pulses to the output drivers for supplying the driver voltage levels.