Pulse Train Control-Based Unbalanced Current Mitigation for Three-Phase PWM Rectifiers Operating Under Non-Ideal Grid Conditions

Abstract

In this paper, the pulse train (PT) control scheme is employed for unbalanced current mitigation in three-phase PWM rectifiers under unbalanced three-phase input voltage conditions. In the outer voltage loop, to prevent the impact of the output voltage double-frequency ripple on the current inner loop, the moving average filter (MAF) is employed. Meanwhile, all-pass filter (APF)-based orthogonal signal generator (OSG) and inverse Clark transformation are employed to construct balanced three-phase current references. In the inner current loop, the PT control scheme is employed to force the three-phase currents to track the balanced references. The proposed control scheme is implemented in the stationary reference frame without rotational coordinate transformation, which simplifies the implementation. Simulation results demonstrate that the proposed control scheme for three-phase PWM rectifiers can effectively mitigate the unbalanced degree and the harmonic distortion of the three-phase currents.