Research On The Key Technology Of Household Grid-connected Photovoltaic Power Generation

The traditional energy shortage, environmental problems have become increasingly prominent today, solar photovoltaic power generation due to its advantages of renewable, inexhaustible, inexhaustible, clean and no pollution, no noise, etc., it has become an important direction of the development of new energy industry in china. Household photovoltaic grid-connected power generation in the photovoltaic power generation system occupies a dominant position, but how to efficient use of solar energy, reduce the unit electricity price, to be the promotion of household type photovoltaic grid-connected power generation of the main problems facing. PV cell characteristic, household photovoltaic grid-connected system in the presence of maximum power point tracking control of some actual problems of strategy and islanding detection technology, grid connected inverter control system. This paper in view of the above issues, the main contents include the following aspects:Firstly, the paper analyses the working principle, photovoltaic cells through the analysis of the simplified photovoltaic engineering mathematical model, and then the simulation model build photovoltaic cell in MATLAB, through the simulation of the model, validates the parameters characteristic curve and manufacturers the battery through consistent.Then, analyzes the main circuit topology of household photovoltaic grid connected inverter type, this paper introduces the basic principle of photovoltaic grid connected control, the grid connected current tracking control, analyzes basic principle of phase locked loop based on, proposes an improved scheme based on the improved single-phase phase-locked loop; the output current loop control strategy to solve the problem of grid connected control the feed-forward of grid voltage; the output current harmonic content is small THD, has good control effectiveness.Then, analyze the basic principle of photovoltaic grid connected control, and for the grid connected current tracking control, analysis of the deficiencies of conventional grid connected current control strategy, improved method of close loop control of the output current feed-forward of grid voltage based on grid connected control problem to solve. The algorithm output current harmonics of THD is small, has good control effectiveness.Finally, analysis of the generation mechanism of islanding of photovoltaic system, delay and NDZ islanding detection active frequency drift method AFD in a conventional problems, and improve the active frequency drift AFDPF positive feedback islanding detection method based on the preparation of periodic disturbance, improved AFDPF anti islanding algorithm procedures, simulation results show that the proposed algorithm fast detection speed, the load impedance characteristic of less influence on the test results.The thesis has seventy-one figure, six tables and seventy-two references.