Research On Single-Phase Grid-Connected Photovoltaic System

For the strenuous energy sources currently, the application of solar energy is paid more attention by many countries all the word than before. Photovoltaic (PV) generation, one method of using solar energy, is very promising. The inevitable trend of the use of solar energy will be the grid-connected photovoltaic system. This paper analyzed the topology of grid-connected system, conversation of energy, maximum Power Point tracing (MPPT), control strategy, islanding effect of grid-connected system.For the single-phase PV grid-connected system, the paper expatiated a suitable topological construction, which doesn't use the industrial frequency transformer or high-frequency transformer with features which the small size, low cost and easy control strategy. The paper discussed the conversation of single-phase energy, also the integer structure based on single chip and DSP the single-phase PV grid-connected system.The author analyzed several methods of MPPT of grid-connected system. And the arithmetic of the average current method has been given to the MPPT of PV system. In this thesis it is demonstrated theoretically that the maximum power-output can be matched by adjusting the duty ratio of the DC-DC circuit.The manipulative model of the single-phase PV grid-connected system's inverted output is upbuilt and a kind of PV grid-connected feedback circuit control strategy is adopted, which is emulated. To eliminate the shortage the author presents an improved based on zero-current control. The resultants of the using MATLAB proved the feasibility and validity.Finally, according the theory, thesis gives the result of the parts of the main topology, and made the circuit board to validate the feasibility in the actual conditions.