IGBT isolation driving circuit with switch control unit and control method thereof

Abstract

The invention discloses an IGBT isolation driving circuit with a switch control unit and a control method thereof. The circuit comprises a pulse driving unit for generating waveform signals with complementary phases, a diode rectification unit, the switch control unit, a driving resistor, a switch-off resistor and an insulated gate bipolar transistor (IGBT), output terminals of the driving resistor and the switch-off resistor are both connected with a grid electrode of the IGBT, an emitter electrode of the IGBT is connected to the ground, an input terminal of the switch control unit is connected with the diode rectification unit, and an output terminal of the switch control unit is connected with an input terminal of the switch-off resistor to control cut-off of the IGBT when the pulse driving unit stops signal output. According to the circuit, the driving energy can be transmitted, the transmission of switch signals is completed, cut-off and switch-on of the IGBT can be well controlled through the switch control unit, the circuit can be applicable to a low-frequency condition, and the practicality is high.

Description

technical field [0001] The invention relates to the technical field of drive circuits, in particular to an IGBT isolation drive circuit with a switch control unit and a control method thereof. Background technique [0002] Current main power devices include MOSFET (Insulated Gate Field Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor), both of which are capacitive gate power devices. Its driving condition is specifically expressed as, when it is turned on, its gate capacitance is charged; when it is turned off, its gate capacitance is discharged. [0003] The basic elements of isolation drive include: drive energy and switching signal. The basic circuit forms of isolation drive include: optocoupler isolation drive and transformer isolation drive. Such as figure 1 As shown, when using the optocoupler isolation driving mode, an independent set of isolated power supply is required to provide energy. The power supply generally needs a power frequency isolation t...

AI Technical Summary

Problems solved by technology

However, when it is necessary to provide low-frequency turn-on, the half-period carrier pulse is in unipolar operation for a long time, and the driving transformer still faces the risk of saturation

[0008] However, the isolated oscillation demodulation IGBT drive circuit has technical problems such as poor inductance buffering effect, incompatibility with low-frequency working conditions, and narrow application range.

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