Topology Analysis of H-bridge Snubber for EAST Fast Control Power Supply

Abstract To solve the problem of voltage overshoot during switching-off transient in H-bridge, an active lossless H-bridge snubber composing of auxiliary switch and snubber capacitor is discussed, which aims to enable the H-bridge to realize a higher voltage and current. When the main switch is turned off, the capacitor absorbs the overshoot energy and the energy is returned to DC side through the auxiliary switch. Compared with the conventional RCD snubber, the voltage overshoot can be limited effectively by increasing the snubber capacitor value without considering ohmic loss. As a result, the working voltage of the switch is indirectly improved. In addition, the problem of resistance volume and heat dissipation has been avoided. All the work had been done provides a useful reference in optimizing the topology structure of Experimental Advanced Superconducting Tokamak (EAST) fast control power supply, which can reduce the volume of power supply and simplify the control strategy.