Application of A Novel Repetitive Control Scheme to Grid-Connected Inverter with Low Controlling Frequency

The integer phase lead compensation repetitive control (IPLCRC) can improve the control accuracy and control effect of the conventional repetitive control (RC). However, with low controlling frequency, IPLCRC may cause low control accuracy of the control scheme and even cause system instability. In order to solve this problem, this paper proposes a fractional phase lead compensation repetitive control based on Lagrange interpolation (L-Type-FPLCRC) to improve the steady state and transient effects under low controlling frequency condition. According to the requirements of system stability and steady-state error, the design method of proposed controller parameters is given, and the superiority of the controller is demonstrated through experimental results.