June-Seok Lee, Kyo-Beum Lee, and Youngjong Ko, "An improved Phase-Shifted PWM Method for a Three-Phase Cascaded H-Bridge Multi-Level Inverter," in Proc. ECCE Conf., Oct. 2017, pp. 2100–2105. > Paper

This paper proposes an improved phase-shifted pulse-width modulation (PS-PWM) method for a three-phase cascaded H-bridge

(CBH) multi-level inverter. In the proposed PS-PWM method, the switches at one leg of H-bridge cell (HBC) only operate and the

switches at other leg are clamped. Therefore, the number of the multi-carrier signals depending on the voltage level can be reduced

in half compared to the conventional PS-PWM method. The proposed method generates the same output voltage level as that of

the conventional PS-PWM. In addition, it achieves the efficiency improvement of the three-phase CBH multi-level inverter and

mitigates high frequency components in the common mode voltage compared with that of the conventional PS-PWM method. The

performance and effectiveness are verified by simulation results of the three-phase CHB 5-level inverter.