Control And Design Of Grid-connected Microinverter Based On Interleaved Flyback Structure

Since the21st century，the world of environmental pollution and energy crisis and otherproblems have become more seriously.Solar energy as a clean pollution-free renewableenergy， contain large reserves， wide distribution， pollution-free characteristics. Solarenergy will gradually replace the use of non-renewable energy，alternative energy evolvedfrom basic energy.Photovoltaic power generation is one of the solar energy industry in the mainstream ofdevelopment. Micro-inverter system and network configuration for each PV module invertermaximum power point work， DC inverse individual PV modules can be directly output intoAC power market followed. This improves the efficiency of power generation andphotovoltaic power generation system， unable to overcome the single PV array maximumpower point tracking of defects， extensions of PV modules application more convenient.This paper studied the interleaved flyback active clamp converter to solve the problemthat the single stage flyback grid-connected microinverter controller switch large loss andproduces high-frequency voltage spike easily. Dual flyback circuit structure can reduce theoutput current of the high harmonics, power decoupling partially replaced with film capacitorselectrolytic capacitors to improve micro-inverter life.Interleaved flyback micro-inverter usespulse width modulation to achieve interleaved conduction, and reduces the output currentripple. Dual control principle expounded the decline flyback inverter and sinusoidal pulsewidth modulation strategy, compares two methods of magnetic energy absorbed by theleakage inductance of the pros and cons.For the interleaved flyback converter load mayappear imbalance, established equivalent numerical mathematical model and equivalentcircuits of micro inverter system.. At last based on the simulation software is designed basedDSPIC2812, maximum output power of210W PV micro-inverter. By comparing thesimulation results with the experimental results of the prototype, the output current waveformand a good network quality, high conversion efficiency, phase zero crossing distortion doesnot meet with the same frequency and phase grid voltage, verified the correctness of thecontrol principle and electronic elements design and selection.