Second-order Higher Gain Repetitive Control for LLCL-type Grid-connected Inverters
Proportional-integral multi-resonant repetitive control(PIMR-RC)has been widely used due to its good harmonic rejection and dynamic performance.However,its robust to frequency fluctuation is poor,and second-order repetitive control(SORC)can provide an effective solution.To this end,the paper applies SORC to PIMR-RC to form a second-order higher gain repetitive control(SOHG-RC),improving the control performance and frequency adaptability of the controller effectively.Firstly,the structure of SOHG-RC is designed.Then the stability and parameter design method of the second-order higher gain repetitive controller are analyzed.Finally,the simulation model of the single-phase LLCL-type grid-connected inverter based on SOHG-RC is developed to do an analysis.The results verify the effectiveness and superiority of the proposed control scheme.