Study On Single-phase Grid-connected Inverter Based On The Crisscross Flyback Topology

With the decline of the non-renewable resources and the serious problems of theenvironment, the development of new energy gradually causes the attention of thehuman. Among them, the solar photovoltaic power generation has become the hot spotof the social research. In view of this, this article uses high-performance dsPIC chip todevelop a photovoltaic converter based on a crisscross flyback topology. In the courseof the study, the article mainly researches for the output characteristics of the PVbatteries, the maximum power point tracking (MPPT), the control strategy and thedesign of software and hardware circuit, and in the end analyses the experimental dataand the waveform.Solar cell is the most basic parts of photovoltaic system. The paper analyses outputcharacteristic curve of the PV batteries and the influence of temperature and lightintensity. And it lays a foundation for the design of the photovoltaic system.The maximum power point tracking (MPPT) determines the utilization ratio of PVcells output energy. In order to make PV cells to work in a maximum power point,according to the disadvantages of disturbance observation method, this paper applies theoptimal gradient method to implement MPPT tracking. Through studying these twomethods, the optimal gradient method has more smaller tracking precision and fastertracking speed.The control strategy of photovoltaic inverter is the important point of design.Control strategy can depends on the high quality of output electric power. This paperadopts the double closed loop PI control and the PR control of the electric circuit, andthrough studying, the grid current has more smaller aberration rate, the phase differenceof grid electric current and voltage is more smaller and system has a strong anti-interference ability.Finally, this article designs the software and hardware circuit of the crisscrossflyback grid inverter in detail, and sets an experimental platform. The experimentalresults show that the inverter gets to the standard requirement basically in the powerfactor, distortion rate and system power.