Control For Inverters In Parallel Operation Based On P-Q Regulation

The modularity is one of the most important research trends in the field of inverter technology. The kernel of the modularity is the control technique of parallel inverters. The capacity expanse of parallel inverters can greatly reduce the power system's volume and weight. The current stress of the power switch is considerably lessened which means higher reliability, lower cost and higher power density.The modeling of parallel inverter system and the principle of PQ regulation are studied. Based on power line communication (PLC) technology and synchronization control of the sinusoidal voltage reference signals among all the inverter modules, the average current sharing strategy by PQ regulation is researched with the method for determining PQ coefficients provided. In order to decrease circulating current of the traditional all-compensation algorithm for voltage reference, the accumulative algorithm is investigated with improved current distribution performance.To solve the problems in practical inverter parallel system such as experimental hazard, the physical equivalent model for inverter is researched and built by theoretical analysis, simulation and experimental verification. The experimental results from both the equivalent inverter parallel system and the practical inverter parallel system prove the feasibility and validity of the equivalent theory and the improved PQ regulation method.