Input‐series‐output‐parallel connected modular high frequency isolated AC–AC converters with positive compensation of inner‐current loop

Abstract

A control strategy for input-series-output-parallel (ISOP) connected modular high frequency isolated AC–AC converter is proposed in this study. The circulating currents among all the constituent modules are avoided by the proposed pulse width modulation sequence generation method. Based on the revealed relationship between input voltage sharing (IVS) and output current sharing (OCS), a stable control strategy is proposed by using an output voltage loop and positive inner-current compensation loops. The individual input voltage sharing loops are eliminated. With the proposed control strategy, OCS or IVS can be achieved well for ISOP modular AC–AC converters under both steady and dynamic state, even in the case when the parameters of individual modules are mismatched. Simulation and experimental results are presented to verify the effectiveness of the control strategy.