Repetitive Controller with Low N-Value for the MLCL-Type Grid-Connected Inverter

The repetitive controller is widely applied in grid-connected inverters to suppress harmonics. For the RC, an array with length N is required to store history samples, which may occupy large memory in digital realization process. In this paper, three low N-value RCs are designed for the modified LCL (MLCL)-type grid-connected inverter by decreasing the sampling rate and increasing the fundamental harmonic frequency of the RC. Finally, experiments are conducted on a 228kW inverter to compare the performance of these three RCs.