An Optimized Parameter Design Method for Passivity-Based Control in a LCL-Filtered Grid-Connected Inverter

Nowadays, the Passivity-Based Control (PBC) has been successfully applied to digitally controlled Grid-Connected Inverter (GCI) with LCL filter. As a nonlinear method, the PBC controller has strong robustness against the parameter drift of the LCL filter and the grid impedance, where the parameters of the PBC controller still need to be designed carefully to achieve a good control performance. The existing design methods are based on separating the PBC controller into three control loops. Therefore, the design process is cumbersome, especially for inexperienced engineers, due to the complex structure of the PBC controller. In this article, an intelligent Particle Swarm Optimization (PSO) algorithm is utilized to simplify the parameters design of the PBC controller, where the difficulty of manual calculations is avoided and the parameters can be more easily and efficiently obtained using MATLAB in offline mode. Furthermore, a Kalman filter observer is adopted to estimate the state variables in the PBC controller, where only the grid-injected current needs to be sampled in the overall GCI system. Simulations and experiments are provided to verify the correctness and effectiveness of the proposed PBC controller design method.