As the rated power of gate-controlled semiconductor devices is getting bigger and bigger, the switching speed is getting faster and the rated voltage is getting higher and higher, it is not enough to only require enough withstand voltage, capacity and excellent high-frequency characteristics for the capacitor of the snubber circuit. . In high-power power electronic circuits, since the switching speed of IGBT is less than 1μs, it is normal to require the voltage change rate on the capacitor of the absorption circuit to be dv/dt > V/μs, and some require V/μs or even V/μs.