基于模型预测控制的级联型光伏逆变器非均匀光照下并网控制策略OA

In the field of grid-connected photovoltaic power generation,the cascaded grid-connected converter shows great development potential,thanks to its capability to boost power generation efficiency under uneven illumination.However,independent maximum power point tracking(MPPT)regulation in each sub-module can lead to DC bus voltage imbalances,undermining system stability.Thus,when controlling grid-connected current,DC bus voltage balance must also be considered,turning the control strategy into a multi-objective challenge.To tackle this,a multi-objective finite control set model predictive control method(FCS-MPC)is proposed for a two-stage photovoltaic cascaded grid-connected converter.This method establishes prediction models for grid-connected currents and DC bus voltages across different switch states.By incorporating PI control and a cost function design in model predictive control,it simultaneously achieves grid-connected current regulation,total DC bus voltage maintenance,and voltage balance among DC buses.A nine-level cascaded H-bridge(CHB)photovoltaic converter model was built in MATLAB/Simulink to test system performance under various conditions.Simulation results show that the proposed method ensures excellent steady-state operation and dynamic response.