Study On Independent Photovoltaic Power Generation Device And System Design

With development of economy, human demand for energy has increased quickly, whilethe energy crisis and environment pollution have become two serious problems. Thedevelopment and utilization of new energy has become the consensus of the world.Therefore, the value of natural and unlimited use of solar energy makes it the focus ofworld’s attention. Among them, the independent PV power generation system is an importantform of utilization of solar energy. Device research and system design are mainly involvedfor independent PV power generation system in this thesis.Firstly, starting from the application of the solar energy and the development status of theindependent PV power generation industry, the independent PV power generation system areoverviewed, including the character of the PV array, the power converter, the energy storageelement and the control methods of the MPPT.Secondly, the main structure of PV power generation system and its circuit topology areidentified, according to the characteristics of converter. Several control schemes of MPPT aresummarized and compared, and the variable step disturbance observer method is selected asthe control method in this paper. On this basis, the simulation model basing on two levelstructure of independent PV power generation system is established, and the simulationmodels and results of push-pull circuit, inverter and the Buck circuit are listed respectively.Finally, all parts of the PV generator device are studied, including main circuit topology,parameter’s calculation and the choice of power components, basing on the design of thesimulation system. The PV device is comprised by the power part and the control part. Thepower part is comprised by the Buck circuit, the front DC/DC push-pull boost circuit, and theback DC/AC full bridge inverter circuit. The control part mostly consists of inverter drivingcircuit, push-pull control circuit, control circuits of MPPT and battery, and auxiliary powersupply circuit. The software design of the MPPT control is realized by MCU. The feasibilityof the PV system design is verified through the MPPT test data. The output result of theexperimental device is standard sinusoidal voltage.