Control strategy for photovoltaic grid-connected inverter with LCL filter

A new control strategy for three-phase grid-connected inverter (GCI) of photovoltaic generation system (PVGS) with LCL filter is proposed. Based on the non-linear 3^rd-order model of the inverter, the robust active disturbance rejection control (ADRC), which is composed by the cascaded tracking differentiators (TD), the 4^th-order extended state observer (ESO), the non-linear PID (NLPID) and the disturbance compensating is designed to enhance the steady and dynamic performances of the PVGS. Experiments on a 10kW prototype are presented to verify the advantages of the proposed approach.