Using fuzzy control for parallel-inverter system with nonlinear-load

It is difficult to obtain a more precise mathematical model of parallel-inverter system with a nonlinear load. Nonlinear load is the general factor which affects output voltage total harmonic distortion (THD) and current sharing. But fuzzy controller can control well without a precise mathematical model. Master-slave control is used to control the parallel-inverter system in this paper. The voltage regulator in outer control loop is fuzzy controller. While fuzzy self-tuning PI controller is designed for current regulator in each inverter. Simulation results show that master-slave control scheduling with new controllers can achieve low THD in the system output voltage and fast dynamic response for nonlinear loads. What is more, it has good current-sharing performance.