利用磁开关来改善全固态Marx发生器的脉冲上升沿,并构建出一套脉冲电源.该套脉冲源包括基于IGBT半桥模块的Marx发生器和由磁开关与锐化电容构成的脉冲陡化电路.该电源用原边一匝的脉冲变压器为IGBT提供驱动信号,并且原副边绕组均采用同轴线以屏蔽电磁干扰;在门极采用无源过流保护的方法,以防止负载短路对IGBT放电开关造成损坏.实验结果表明:在电压10 kV,电流170 A的情况下,脉冲前沿由1.5 μs压缩到了200 ns,同时IGBT的开通损耗由原来的10 mJ降到不足1 mJ.
The method of using magnetic switches is proposed to reduce the voltage rise time of the all solid-state pulse source and a generator is constructed. This generator consists of a Marx modulator based on isolated gate bipolar thyristor(IGBT) half bridge modules and a magnetic pulse sharpening circuit, which is employed to compress the rising edge of the Marx output pulse. The approach of using multiple small driving transformers, one-turn primary windings of which are in series connection, provides a simple way for gate drive. Coaxial cables are employed as both primary and secondary windings of these transformers for electro-magnetic interference(EMI) shielding. A passive over-current protection measure is adopted so as to promise safe operation of the discharging IGBTs. The experimental results show that the rise time of the Marx output pulse is reduced from 1.5 μs to 200 ns under the condition of 10 kV and 170 A, and the single IGBT turn-on loss is reduced from 10 mJ to less than 1 mJ. The design of IGBT drive circuits and magnetic switches is introduced in detail in this paper.