A Novel State-Observer-Based PBC Controller for LCL-Filtered Grid-Tied Inverter with Less Sensors and Zero Steady-State Error

The Passivity-Based Control (PBC) has been adopted in LCL-filtered grid-tied inverter (GTI). However, the conventional PBC method depends much on accurate mathematical model, where zero steady-state error can't be realized when the accurate model parameters are not available or parameters drift occur. Furthermore, due to the utilizing of three state variables in the conventional PBC controller for LCL-filtered GTI, twelve sensors (voltage and current) must be used in a three phase system, which increase the costs and the failure rate of hardware. In order to handle the problems, a novel state observer based modified PBC (SOMPBC) controller for LCL-filtered GTI is proposed in this paper. Six sensors can be saved by the state observer and zero steady-state error can be easily realized by two modified control methods, where an integral regulator is insert into the conventional PBC controller with two different ways. Simulation platform is built in MATLAB/Simulink and a 3-kW experimental device is carried out with DS1202 to verify the correctness and effectiveness of proposed control method.