Research on grid-connected photovoltaic inverter based on quasi-PR controller adjusting by dynamic diagonal recurrent neural network

摘要

The single-phase grid-connected photovoltaic inverter system is studied in this paper. In view of the non-linear and time-varying characteristics of this system, the three-closed-loop control strategy consisting of DC voltage outer loop, grid-connected current inner loop and capacitive current inner loop based on quasi-PR control is proposed. Since the quasi-PR controller of fixed parameters is unable to adapt to changes of parameters in power network, a quasi-PR control method of dynamic self-tuning based on a dynamic Diagonal Recurrent Neural Network (DRNN) is presented. DRNN is based on the Recursive Prediction Error (RPE) algorithm with second-order gradient, which has a faster convergence rate than the BP algorithm. The simulation and experiment results prove that the grid-connected photovoltaic inverter with the above control algorithm has a good quality of the output current and fast performance in dynamic response.