Study on smooth-transforming feed-forward control strategy of the inverter in double operation modes

Abstract

In this paper, a feed-forward control strategy of the inverter, in which the double operation mode including stand-alone operation and grid-connected operation can be smoothly switched, is proposed. When the inverter is operated under the current-mode grid-connected power generation, the feed-forward control of grid voltage is employed, which can improve the dynamic performance of the inverter and suppress the current impacting to the grid. And when the inverter is in the voltage-mode stand-alone operation, the feed-forward control of off-grid voltage reference is adopted to reduce the switching delay and to restrain the impact of the electricity. With the synchronous switching of the mode switch and the selection switch to select the corresponding feed-forward, the switching of the inverter at any time in double operation modes can be easily realized. Experiments show that the method of feed-forward control in this paper can realize the smooth switching of the inverter in the double operation mode of stand-alone operation and grid-connected operation.