Circulating current control for parallel interleaved VSCs connected in whiffletree configuration

This paper presents a Proportional Resonant (PR) based circulating current controller for four parallel interleaved Voltage Source Converters (VSCs). Interleaving the carrier signals will cause a switching frequency circulating current to flow between the VSCs. Therefore, to suppress these circulating currents the VSCs are interconnected through Coupled Inductors (CIs), which form a whiffletree configuration, and they are used to suppress the switching frequency circulating current. On the other hand, the CIs are highly sensitive to fundamental frequency circulating currents, which may saturate them. Hence, a circulating current controller is required, which effectively controls the fundamental component of the circulating current. Furthermore, the circulating current is sampled using a special technique, which does not require any additional. The effectiveness of the design methodology and the performance of the circulating current controller are verified by simulation and experimental results as well.