PWM Sensor-less Balancing Technique for the Fifteen-Level PUC Converter

In this paper, a novel PWM technique insuring the self-balancing of the capacitors voltages has been proposed for the attained nine-level packed U cells (PUC) converter. In the traditional fifteen-level operation, the capacitors voltages have to be maintained around their references using a state variable feedback which requires three sensors, two for the capacitors voltages and one for the load current. By applying the proposed PWM technique to the fifteen-level PUC converter, self-balancing of the capacitors voltages is attained, which results in the proposed nine-level converter. The proposed balancing technique is achieved without any closed loop regulation or sensors. The proposed concept has been verified by mean of simulations performed in the Matlab Simulink environments. Simulation results show that even under severe DC bus voltage and load parameters variations, the capacitors voltages remains around their required values. Harmonics contents of load current depend on the modulating signal frequency. Moreover, even under low frequencies, the total harmonics distortion remains reduced.