Direct power control of PWM rectifier under unbalanced grid voltage

Abstract

PWM rectifier controlled by direct power control (DPC) is characterized by the merits of quick response, no need of inner current tuning and strong robustness, etc. However, conventional table-based DPC cannot work properly when the grid voltage is unbalanced. Various methods have been proposed to mitigate the influence of grid unbalance but they are usually complicated and require positive/negative sequence extraction of grid voltage and/or currents. This paper proposed a novel DPC, which can achieve sinusoidal grid currents and constant active power without using complicated sequence extraction. The simplicity and robustness of conventional DPC is maintained due to the use of a novel reactive power definition. Its effectiveness is validated by simulation and experimental tests.