| BIPV is developing more and more fast in recent years, family-photovoltaic systems are gradually emerging, this brings opportunities on to the development of single micro-grid PV power generation system.The micro-inverter is an extremely important part of micro-grid system.This article propose a series resonant push-pull micro inverter which is based on the research of common micro-inverter topology,the ZVCS circuit of this inverter is able to form a resonant circuit. The switching loss of series resonant push-pull micro inverter is small, it is possible to improve the efficiency of the converter. The main work is done as follows:Firstly, analyzed several major micro-inverter topologies detailed and their advantages and disadvantages are compared and analyzed, the final choice is series resonant push-pull inverter, with a series LC resonant circuit and soft-switch technology push-pull micro-inverter as the object of study.Secondly, with the study of series resonant push-pull inverter, this article carried out careful analysis and study of the principles of its hardware and software programming based on PIC micro-controllers. Hardware circuit includes DC / DC circuits, DC / AC circuits, current and voltage detection circuit, zero-crossing detection circuit and so on; software programming includes the main program, fault detection procedures, alarm procedures.Thirdly, micro-inverter control strategies were studied. Determined perturbation and observation method of MPPT based on variable step size; proposed control strategy of SPWM based on current tracking, feedforward control strategy, tricyclic control strategy; analyzed the principles of soft-switching technology, and used experimental waveforms to verify it.Finally, using Matlab software to simulate micro-series resonant push-pull inverter and the actual experimental waveforms have been studied and analyzed by comparing the simulation and experimental waveforms, which validate the rationality and feasibility of the program. |
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