Elimination of Circulating Current in a Parallel PWM Rectifier Using an Interface Circuit

Parallel pulsewidth modulation rectifiers are a good solution for high-power ac–dc applications, which enhance quality and reliability. However, the main and inevitable shortcoming of parallel structures is a generation of circulating current. Various methods are proposed to reduce or eliminate circulating current, most of which tend to change or limit the switching pattern of parallel converters. This article presents an interfacing circuit with low rating elements, which eliminates the circulating current without any limitation for the switching pattern of parallel converters. Therefore, voltage and current waveforms are in high quality. Moreover, unlike previous methods that had complex control and high mathematical computations, the presented method has simple control. Therefore, multiple modules can be implemented in a modular fashion with a fast dynamic response. Simulation and Laboratory results are presented to validate the analysis.