Research On Photovoltaic Micro Inverter

Under the circumstance that the ecological environment is continuously destroyed and the traditional fossil energy is facing depletion,it is imperative to accelerate the application research of renewable energy.Among renewable energy sources,the use of solar energy has attracted much attention.Photovoltaic power generation is a proof that solar energy is widely used.At present,the research on photovoltaic power generation systems is seen,and the most promising is the micro-photovoltaic grid-connected inverters.Therefore,the research on micro-photovoltaic grid-connected inverters is of great significance for larger-scale photovoltaic power generation.Then,by analyzing the key technologies of the micro-inverters,the disturbance observation method has been optimized to enhance the stability of MPPT.Based on the flyback converter circuit.The staggered parallel flyback converter is introduced as the topology of the pre-DC-DC converter circuit,and then the full-bridge inverter is used as the topology of the rear-stage DC-AC circuit;the control loop is simplified for the grid-connected side.The current PI loop compensation and voltage feedforward compensation based on fuzzy inference is selected as the control strategy.An improved periodic bidirectional positive feedback active frequency shift method is proposed for island monitoring.The above control algorithm is simulated and verified in MATLAB/Simulink platform.The results exhibit that the algorithm used in the thesis can satisfy the performance requirements of photovoltaic grid-connected micro-inverters.Both the hardware and software of photovoltaic grid-connected micro-inverters based on FPGA have been designed in this thesis.The Verilog language was used to complete the RTL design of the system.A 220 W photovoltaic grid-connected micro-inverter prototype is designed using Altera's FPGA EP4CE15E22C8.The experiment directly used the photovoltaic panel as the micro-inverter input and the experimental results exhibit that the grid-connected current is relatively stable.The total distortion rate is not greater than the GB/T 3047-2013 standard.Figure [62] Table [4] Reference [60]...