High Performance Control of Three-Phase Three-Level Rectifier under Unbalanced Conditions

In this paper, a new control scheme based on the utilization of the natural variables of the system is proposed for the three-phase three-level rectifier working under unbalanced conditions. The attractive advantage of this controller is the possibility of effective operation under both balanced and unbalanced voltage/line impedance conditions. Unity power factor operation is feasible when the system is balanced and a constant input power can be achieved in unbalanced situation. Simulation results demonstrate the effectiveness of the controller in both the rectifier mode and the inverter mode.