The distortion of background harmonic voltage is inevitable in grid-connected system

which would result in serious low-order harmonics in the injected grid current. The low-order harmonics can be suppressed by increasing the switching frequency

while it also brings many high-order harmonics. Based on PR+HC-based current controller

the effects of the current controller parameters on steady-state error

phase margin and gain margin in LCL-type grid-connected inverter are investigated. A method is given to obtain the controller parameters’ region that meets the requirements

and the optimal parameters could be obtained on the basis of analysis in system stability. Simulation results verify the proposed control scheme and parameters design method.