Improved inverter parallel control strategy based on instantaneous current-sharing control

For the issue that the voltage of the inverter parallel system changes greatly with the output load dynamic changes, an improved current-sharing control method was proposed. Based on the traditional inverter model with output voltage feed-forward and double close-loop control method, the load-current feed-forward control method was added. The effect of load-current feed-forward control on the dynamic performance was analyzed in two different ways. Besides, based on the instantaneous closed-loop controller, the proposed regulator of the parallel system was designed according to the droop characteristic of the current circulation. Finally, a parallel system with 6×20 kVA inverters was established. The experimental results show that with the proposed control method, the current-sharing error of the system is greatly decreased. Compared with the traditional method by the hardware signals, this method is not susceptible to interference. And the results also show that the proposed method has good steady-state and dynamic performance. © 2019, Harbin University of Science and Technology Publication. All right reserved.