Multiband hysteresis controller of the novel three phase seven-level PUC-NPC converter

Due to recent energetic crisis, multilevel converters have been deeply studied to fulfill the growing demand with a high energetic efficiency. In this paper, authors propose a six-band hysteresis technique to control the novel seven level PUC-NPC converter. This converter combines advantages of the Packed U Cells (PUC) and the Neutral Point Clamped (NPC) topologies. A technique which allows a good system behavior and a low total harmonic distortion (THD) is proposed. In case of rectifier operation, the proposed six-band controller is designed to draw a sinusoidal line current (load current in case of inverter operation) with a unity power factor. Harmonics contents of line current (or load current) and rectifier input voltage (or inverter output voltage) are then very reduced which permits the reduction of the rating of active and passive filters resulting on a very high energetic efficiency and a reduced installation cost.