A new five-level hybrid-clamped converter with reduced number of clamping devices

In this paper a new five-level hybrid-clamped converter with reduced number of clamping devices is introduced. Only two active switches and two flying capacitors are used for clamping per phase. The operating method is introduced and phase-shifted pulse width modulation (PS-PWM) is used to control this converter. A detailed analysis of the average currents through the flying capacitors and neutral points of the DC-link is presented. Based on the analysis, it can be concluded that the voltages across the flying capacitors and DC-link capacitors can be naturally balanced under ideal and steady-state conditions. In the actual system, the DC-link capacitor voltages are balanced by using classic zero-sequence voltage injection and the flying capacitor voltages are controlled by adjusting the switching duty cycles of four PWM signals. Simulation and experimental results are presented to confirm the validity of this topology.