Research On Grid-connected Photovoltaic Inverter System

The inverter system is the key component of grid-connected PV system, and its performancedirectly determines the quality of the entire system. Creating a system simulation model throughMatlab/Simulink, it analyzes and researches the system model, control strategy, islanding detectionand other key issues. A set of5kW single-phase grid-connected photovoltaic inverter system iscreated based on the researches, and it gives the system topology and circuit parameters.Firstly, the paper accounts the significance of the research, introduces the current situation andprospects for the development of photovoltaic power generation at home and abroad. It overviewsthe structure classification, topology, control strategy, the maximum power tracking method,islanding detection technology of photovoltaic power generation simply.Secondly, it introduces the network standards of photovoltaic grid-connected inverter system,analyzes the topology, modulation mode, the system block diagram and working principle.Thirdly, it designs the main circuit and control circuit of a5kW single-phase grid-connected PVinverter system. Based on the DSP (TMS320F2812), it creates a5kW single-phase grid-connectedPV inverter system and gives the experimental waveforms.Then, the paper analyzes the structure and equivalent model of the single-phase PVgrid-connected inverter. Simulation model is built through Matlab/Simulink, and the results showthat the modified proportion resonant control has a better performance than the traditionalproportion-integral control and the proportion resonant control.Finally, it discusses several islanding detection methods, including passive and active typedetection methods. The simulation results show that the AFD active method is simple, reliable andfits for the actual circuit.