Compound Suppression Strategy for Phase Circulation Current of Microgrid Parallel Inverters Based on Sliding Mode Control

The issue of phase circulation in parallel inverters within low-voltage microgrid systems critically affects power quality and conversion efficiency at the microgrid's output. To address this challenge, this paper presents a compound suppression strategy for phase circulation (CSSPC) based on sliding mode control (SMC). The strategy is composed of two key components. The first component involves the design of a robust droop SMC controller, which is tasked with suppressing inter-phase circulating currents while enhancing the precision of power allocation within the system. The second component is the design of a zero sequence voltage SMC suppressor, which incorporates a regulatory factor to indirectly suppress intraphase circulating currents by eliminating zero sequence voltage. Simulation results have confirmed that the proposed control strategy enhances the robustness and output performance of the parallel inverter system, simultaneously providing effective suppression of phase circulating currents.