An Improved Phase-Shifted PWM for a Five-level Hybrid-Clamped Converter

Five-level hybrid-clamped (5L-HC) converter is a newly proposed topology which is suitable for medium-voltage high-power conversions without switches directly connected in series. Phase-shifted PWM (PSPWM) is commonly used to control this converter. However, the line voltages of PSPWM include many intervals that jump two voltage levels continuously, which will deteriorate the harmonic performance. This paper proposes an improved PSPWM method for the hybrid five-level converter, which can imitate the effect of phase disposition PWM (PDPWM) and improve the quality of the line voltages. Simulation and experimental results verify the validity of the proposed method.