Research And Design Of Grid-Connected Photovoltaic Microinverter

Entering the 21th century, the population continues growing. The traditional fossil fuels such as coil, coal and natural gas become increasingly intense. It makes people realize that the renewable energy is of great role and meaning. Among these renewable energies, the solar is of the most focus. Solar energy is the most promising renewable energy because solar energy is a resource-rich, widely distributed renewable energy. And the solar grid-connected micro inverter technology is the key technology of photovoltaic power generation system. Therefore, it is of great theoretical and practical significance to study this inverter technology in-depth.This thesis focuses on the design and implementation of the inverter of a micro-grid-connected PV system. The main contents can be summarized as follows:(1)By comparison and analysis of topologies of the PV inverter which are the most commonly used, a micro PV grid-connected inverter system has been designed based on the parallel interleaved flyback topology with active clamp circuit.(2)A current loop compensator has been designed to make the system steady. Besides, a MPPT and islanding detection algorithms have been designed. PLL is designed to make the system synchronize the output current with the grid voltage.(3)Several simulation models are established by MATLAB/SIMULINK to make sure the MPPT and the whole system can work right.(4)A prototype is designed. The hardware includes a main circuit, drive circuit, detection circuit and auxiliary power circuit. The software includes MPPT, PLL and islanding detection algorithms, current loop compensator and so on.(5)Testing and debugging the whole system, several important data and waveforms has been given to draw the conclusion. And this thesis finally summarized the whole system and pointed out some problems. The future work was proposed too.