New low loss quasi-parallel resonant DC-link inverter with lossless variable zero voltage duration

A new low loss quasi-parallel resonant DC-link (NLQPRDCL) inverter which shows highly improved PWM capability, low loss characteristic and low voltage stress is presented. A method to minimize freewheeling interval, which is able to largely decrease DC-link operation losses and to steadily guarantee soft switching in the wide operation region is proposed. In addition, lossless control of zero voltage duration of the DC-link makes the proposed inverter maintain the advanced PWM capability even under a very low modulation index. Simulation and experiment are performed to verify the validity of the proposed inverter.