基于窄脉冲传输的脉冲展宽IGBT驱动电路

设计了一种采用高压隔离脉冲变压器传输窄脉冲,然后应用脉冲展宽电路实现宽脉冲驱动信号输出的无源IGBT驱动电路。采用正电压turn-on窄脉冲和负电压turn-off窄脉冲组合传输的方式以减小高压隔离脉冲变压器的体积和重量,脉冲展宽电路使IGBT在turn-on脉冲上升沿导通,在turn-off脉冲上升沿关断,且其具备储能功能,无需高压隔离辅助直流电源为其供电。脉冲信号发生电路和过流保护电路耦合设计,使IGBT在正常关断和过流保护关断情况下,其栅极都处于反压偏置状态,以提高IGBT关断的快速性和可靠性。将驱动电路用于级联Marx高压电路中IGBT开关的驱动,turn-on脉冲和turn-off脉冲的脉宽均选择为2μs,结果表明,Marx电路在输出脉冲电压峰值为20 kV时工作稳定,且脉宽在3.5~50μs之间连续可调,等离子体负载下的输出电压和电流波形显示,打火情况发生时,过流保护电路工作稳定可靠。该驱动电路可有效实现宽脉冲驱动信号的产生,具有较强的可靠性和实用性。

This paper proposes a driving circuit for IGBTs with long duration gating signals output,by which only narrow pulses are transferred by the high-voltage isolation pulse transformer and no high-voltage isolation DC power supplies are utilized.Narrow positive pulse“turn-on”and negative pulse“turn-off”are both transferred by the pulse transformer which is smaller and lighter,comparing with that transferring long duration gating signals.The pulse width broadening circuit turns the IGBTs on at the rising edge of“turn-on”pulse and turns the IGBTs off at the rising edge of“turn-off”pulse,and it also stores energy from“turn-on”pulse,without high-voltage isolation DC power supplies.Narrow pulses generator and over-current protection circuit are interactively designed to produce negative voltage pulse on the gate of IGBTs,which reduces the turn off transition period and enhances the turn off reliability,whether the IGBTs are normally turned off or closed due to over-current protection.The proposed driving circuit is applied to the cascaded high-voltage Marx generator,and the pulse widths of“turn-on”and“turn-off”pulses are both 2μs.Experimental results show that the Marx generator functions well with maximum voltage output of 20 kV and pulse width at 3.5~50μs.When arcing generates at plasma load,the over-current protection circuit reacts quickly to turn off the IGBTs with high reliability.The performance of the driving circuit proves its capability of producing long duration gating signals for IGBTs with high reliability and practical validity.