Bi-directional Three-phase Current-Source PWM Inverter Introducing Zero-Current Soft-Switching Technique

Abstract

Although power semiconductor devices such as IGBTs and GTOs have been widely used for high power industrial applications, turn-off losses of those devices due to the current tail characteristics dominate their total switching losses. A soft switching technique is very effective in cutting down the switching losses.
We have proposed an energy storage system using a current-source inverter (CSI) and a zero-current switching bi-directional DC-DC converter with a simple L-C resonant circuit in our previous works. However, based on those works, the CSI circuit is turned on and off with a hard switching technique. Improvements of efficiency and performance of CSI are indispensable to implement the proposed system.
This paper proposed a soft-switching bi-directional circuit topology. The switching losses of CSI are reduced by adding a commutation circuit. In order to verify effectiveness of the proposed system, the system is analyzed in terms of the characteristics of switching losses and conversion efficiency, through a theoretical approach and computer simulations based on an instantaneous value analysis model.