A simplified discontinuous-switching-modulation for three-phase current-fed PFC-converters and experimental study for the effects

The authors propose a new modulation scheme to obtain discontinuous switching in instantaneous current-controlled three-phase buck and buck-boost power factor correction (PFC) power converters. Since the proposed discontinuous switching modulation eliminates the switching actions which produce the highest energy dissipation in modulation period, the average switching loss is reduced by half. The loss reduction effect is analyzed theoretically and experimentally. Further, a simple scheme to generate the discontinuous switching patterns in the instantaneous current controller is introduced. The validity of the theory and applicability of the discontinuous switching modulation in practice are confirmed through experimental results obtained from 2 kW prototype power converters.