Multi-loop Feedback Analysis of Distributed Power Inverters in Microgrids

As a new type of energy storage device and control system, microgrid can solve the problem of traditional energy sources due to limited resources and high development costs. It changes the relationship between the participants in the power system by controlling the inverter output so as to achieve a balanced energy exchange and distribution of the whole power system. The access to non-linear loads leads to an increase in the harmonic content of the inverter output current, which seriously affects the quality of the output current of the parallel inverter and also the operational efficiency of the inverter. The aim of this paper is therefore to design a correct and effective control strategy to enable the parallel system to operate stably. The author focuses on the circulating impedance of the inverter parallel connection, based on which a multi-loop feedback analysis of the parallel inverter for distributed power supplies in microgrids is carried out to improve the operational efficiency of the parallel inverter system in terms of suppressing the circulating current size and reducing the harmonic content of the inverter output current.