A simplified three phase three-level zero-current-transition active neutral-point-clamped converter with three auxiliary switches

A novel three-level zero-current-transition active neutral-point-clamped inverter is presented in this paper. The proposed soft-switching topology employs only one auxiliary switch, one LC resonant tank to assist the main switching devices in one phase leg. The zero-current turning-off of all the main and auxiliary switches are achieved with voltage stress of all switching devices are clamped to half of the DC-link voltage. Meanwhile, The turning-on losses of switches and reverse recovery losses of diodes are reduced. The control scheme is simple and no additional sensor is needed and no need modification to the normal PWM strategy. The operation principles are analyzed and simulation result verify the analysis.