Design and optimization of voltage clamps for voltage source inverters

The authors describe various voltage clamp circuits for voltage source inverters, operated either in the hard switching or soft switching mode. The characteristics of the different circuits are compared, and the theoretical results are supported by experimental measurements. Design procedures and design rules are set out and used to optimally design the clamp circuits. The designs are optimized with regard to design time, peak component voltage stresses, and the required minimum on- and off-states of the main switches