Series connection of power switches for very high-power applications and zero-voltage switching

The basic theoretical analysis for series connection of semiconductor power switches (valves) for zero-voltage switching (ZVS) is presented. The influences of the switching device parameters on its voltage distribution during steady and transient-state conditions are analyzed. When ZVS technique is used, the design of the voltage equalization elements is easier than when hard switching is used. Simulated results are presented to validate the analysis and design methodology. This work is important for very high-power soft-switching valves and converter designs. As an example to validate the theory, a study based on the gate turn-off thyristor (GTO)-controlled series capacitor is presented.