Comparison of ZVS operation modes with and without phase shift for three-level resonant converters

Three-level resonant converters combine the desired features of low voltage stress and low switching loss and are suitable for high power high voltage applications. Phase-shift (PS) and nonphase-shift (NPS) operation modes are both used in three-level resonant converters. In this paper, the two operation modes are analyzed and compared for a three-level parallel resonant converter, with respect to power losses, component stresses, and parasitics impacts. Results show that the converter can achieve more benefits operating in the NPS operation mode. The experimental results using a 200 kHz, 30 kW DC/DC converter validate the theoretical analysis. The results can be extended to other three-level resonant converters.