Multibandwidth Repetitive Control Resisting Frequency Variation in Grid-Tied Inverters

In this article, multibandwidth repetitive control (RC) is developed and applied to a grid-tied inverter to resist grid frequency variation. In the proposed RC, each of the resonant bandwidth is set individually by the gain of the internal model filter. A design procedure for the internal model filter is proposed, which splits the filter into several zero-phase finite impulse response (FIR) filters for reducing the design difficulties. The control structure and stability analysis show that the gain of the multibandwidth RC is increased. An example design procedure for the multibandwidth RC is presented in detail. Comparison experiments with different RCs are performed under deviated grid frequencies, and the results demonstrate the effectiveness of the proposed multibandwidth RC scheme.