The Application Research On Energy Storage And Inverter Of Off-grid Photovoltaic System

With the increase of world population and the development of economy, the need of energy is further increased. In the current structure of the world’s energy consumption, coal, oil and natural gas and some other fossil fuels still account for the major part. Renewable solar energy with its abundant resources, no need of transportation and no pollution has been widely concerned. At present, photovotaic power technology has showed its wide range of applications. Off-grid photovoltaic system is an important component of photovoltaic system.Based on the research of off-grid PV system energy storage and inverter, this thesis describes the basic principles and development of off-grid PV system, analyzes the output features of PV cells and introduces the charging methods of PV cells.By analyzing the topology of the charging controller and inverter circult in the system, make sure the circult structure. This thesis also analyzes the control methods performed for maximum power point tracking in PV system and methods of battery charging using smart MPPT (Maximum Power Point Tracking) which is based on the theory of fuzzy theory. Based on that, a 300 W PV inverter device is designed.This thesis introduces the overall structure of off-grid PV system, MPPT control block and its simulation based on fuzzy theory and proposes three-stage battery charging method and strategy combining MPPT. The thesis also introduces the design of a 300W single phase pure sine wave inverter device based on SG3525 and TDS2285. A prototype has been made. This thesis mainly concentrates on the design of off-grid PV system inverter power circuit, drive circuit and protection circuit and gives relevant results. Based on the analysis of the energy storage and inversion of the photovoltaic system in the off grid, this thesis treats the single-phase pure sine wave inverter as the important point. The inverter uses new control chip with high effciency and green energy and designs the fornt stage boost circults and the back stage inverter circults. By analyzing the experimental data, the inverter achieves the expected designe objectives. It has a good practical significance for the study of small off-grid PV system.