Sdudy Of Quasi-single-stage Interleaved Parallel Flyback Micro-inverter

Photovoltaic grid inverter as the core of the photovoltaic power generation system,is going forward to the high efficiency,high reliability,high power density and low cost.With the advantage of flexible installation,high conversion efficiency and low cost,microinverter is becoming the focus of research in recent years.In this paper,the topology and control strategy of the photovoltaic grid connected microinverter are studied.The simulation model is built to verify the feasibility of the theoretical analysis,and the experimental platform of the photovoltaic grid connected micro inverter is designed.In this paper,the microinverter adopts two-stage approach.Compared with different DC-DC topology,the former uses topology of the interleaved parallel flyback converter circuit.Compared with different DC-DC topology,the latter uses topology of the full-bridge inverter circuit.The active clamp circuit can improve the conversion efficiency and EMI uses LC filter circuit.The overall system simulation model is built in Simulink to verify that the topology selection can meet the requirements of PV grid-connected inverter.In view of the maximum power point tracking control algorithm,this paper proposes an improved perturbation observation method and builds a simulation model in Simulink to verify that the algorithm has good tracking effect and sensitive response.In Simulink,The simulation results show that the islanding effect can be detected quickly.The main component parameters are calculated,the appropriate component model is selected,and the hardware circuit is designed.A 250 W interleaved parallel flyback photodiode is built in the laboratory.Net micro-inverter prototype experimental platform,the grid-connected experiments and inverter conversion efficiency statistics.The experimental waveforms verify the feasibility of the theoretical analysis and realize the basic function of photovoltaic grid-connected power generation.The total harmonic current of inverter output current conforms to the national grid-connected standard,and the inverter conversion efficiency is also ideal.