Voltage equalizing protection control circuit for series IGBT

Abstract

The present invention discloses a voltage sharing protection control circuit of series IGBT, and the structural feature is the setup of the voltage change rate control circuit and the terminal voltage clamp control circuit, wherein the voltage change rate control circuit is composed by a one-way conducting diode D2, a charge-discharge capacitance C1 and a resistance R2; during switch off time of the IGBT, the conducting diode D2 and the capacitance C1 in charged state constitute IGBT external capacitance parallel to CG end of the IGBT; during conducting time of the IGBT, the capacitance C1 takes resistance R2 as discharge path; the terminal voltage clamp circuit is composed by a triode T1 and T2, the clamp state is that DC passes through triode T2, diode D3 and charge grid capacitance of the IGBT. The present invention constitutes control circuit with simple analog elements, realizes IGBT switch voltage waveform similar to standard curve, and realizes different voltage change rate in different stages of the switch process.

Description

technical field [0001] The invention relates to an IGBT control circuit, more specifically an IGBT control circuit suitable for high-voltage converters in high-voltage direct current transmission systems and high-voltage frequency converters based on IGBT series connections. Background technique [0002] Insulated gate bipolar transistor (Insolated Gate Bipolar Transistor---IGBT) was developed in the early 1980s in order to solve the high turn-on voltage of MOSFET, which was difficult to manufacture with high voltage and high current characteristics and low operating frequency of GTR. A double mechanism composite device (Double Mechanism Device) that appears due to insufficient power of the drive circuit. Because it combines the advantages of MOSFET and GTR, it not only has the advantages of high input impedance, fast speed, good thermal stability, simple driving circuit, small driving current, etc., but also has small on-state voltage drop, high withstand voltage and withst...

AI Technical Summary

Problems solved by technology

[0007] The distributed inductance of the device lead and the characteristics of the absorption circuit of the cascaded device are inconsistent, which will lead to different switching characteristics and voltage spikes. The static voltage is unbalanced, and the device that is turned on after the turn-on process is subjected to an overvoltage that may be several times higher than the normal voltage

At the moment of transition of switching devices, different switching characteristics will also be displayed, which will lead to dynamic voltage imbalance of series devices

[0008] 2. The delay of the gate signal of the series IGBT

However, the switching loss of the series IGBT and the control loss of the control circuit are large

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