A Modified DPS PWM Strategy for Parallel Three-Level Inverters to Suppress Circulating Current

This article presents a modified double phase shifted pulse width modulation (MDPS-PWM) strategy designed to suppress circulating current in parallel three-level inverters. In contrast to the double phase shifted pulse width modulation (DPS-PWM), the proposed MDPS-PWM introduces a deliberately chosen phase shift angle for circulating current suppression. By incorporating this targeted phase shift, the strategy effectively reduces the amplitude of the difference in common-mode voltage. This modification leads to a significant decrease in circulating current without compromising the overall output current quality. Furthermore, a sawtooth carrier-based modulation (SCBM) strategy is employed for simplified implementation of carriers. Both simulation and experimental results validate the effectiveness and superiority of the proposed MDPS-PWM method.