(1. School of Electrical Engineering and Automation, Hefei University of Technology, Hefei 230009, China; 2. Sungrow Power Supply Co. Ltd., Hefei 230088, China)

An output impedance decoupled control strategy for the microgrid inverter is proposed to solve the problem with the dynamic voltage response and load sharing. According to the Thevenin equivalent model of output voltage in the dq reference frame, impedance characteristics in different frequency ranges are obtained and dynamic and steady output impedances are then separated. Therefore they are designed directly in the dq reference frame for decoupled control of dynamic response and load sharing, respectively. In order to improve dynamic voltage response, output current derivative control and dynamic active damping are proposed to decrease dynamic output impedance. To improve load sharing, steady output impedance control is proposed to increase stable impedance. The effectiveness of the theoretical analysis and control strategy is verified by experimental results. This work is supported by National Key Technologies R&D Program (No. 2014BAA04B02).