Direct synthesis and systematic design of a multi‐objective controller for grid‐connected inverters under weak grid conditions.

A systematic approach for synthesis and tuning of the controller for grid‐connected inverters with LCL‐filter is proposed in this study. The design objectives like current tracking, harmonics rejection, resonant damping and extended stability over wide grid variations are addressed. Controller structure is synthesised by direct synthesis approach which leads to a systematic design procedure and tuning method. Low‐frequency approximation of the system under worst grid condition is used for the synthesis of the current controller and the resonance component is handled separately. Tunable parameters are identified to investigate grid variations in the process of augmenting the synthesised controller for realisability. Complete design, stability analysis and tuning are dealt with directly in the discrete domain. Detailed simulation and experimental validation are carried out on a 1 kW prototype inverter. The method proposed in this study serves as a simplified design tool for effective design of a multi‐objective controller for grid‐connected inverters. [ABSTRACT FROM AUTHOR]