Design and analysis of the controllable output impedance method for parallel single-phase inverters

A controllable output impedance method for parallel inverters system is proposed in this paper. The control strategy uses LCL filter in output side and add a current loop to adjusting the output current of the inverter bridge. With this modification, the output impedance of inverter is compensated to a specific value then the difference of line and filter impedance can be neglected. Redesigned output impedance reasonable can achieve power sharing with power rating ratio. Simulation results are presented to prove the efficiency and feasibility of proposed control strategy.