DC voltage control strategy for a five-level converter

This paper describes a control method for a three-phase five-level diode-cl amp pulse width modulation (PWM) converter considering de-link capacitor vo ltage balancing problem, The proposed control circuit uses multiband hyster esis comparators (MHC's) to simplify the control of the main circuit. The d e-link capacitor voltage balancing problem is solved by changing the shape of the MHC, The proposed method can 1) overcome voltage imbalance at the dc-link capacitors; 2) achieve a unity power factor; 3) generate nearly sinusoidal input currents; 4) regenerate electric power back to the power system. Simulation and experimental results demonstrate the validity of the propose d method.