Suppression of Current Harmonics in Grid-Connected inverter Using Equivalent Odd Proportional Multi-Resonant Controller

The current harmonics will seriously degrade the power quality of injected current in the gird connected inverter. The proportional resonant (PR) control as effective method can selectively suppress current harmonics at a certain frequency. However, proportional multi-resonant controllers(PMR) will greatly increase the structure complexity and calculation burden. In this paper, an equivalent odd proportional multi-resonant (OPMR) control based on repetitive control (RC) is proposed. Compared with PMR control, the proposed controller is simpler in structure, and multiple odd harmonics can be inhibited simultaneously. Whats more, a complete equivalent mathematical relationship between PMR and OPMR is presented. The validity of proposed method is proved by simulation and experimental results.