Controller For PV Power Generation Unit Applied In Super UPS

Photovoltaic technology as an important form of utilization of solar energy, gains more and more attention.PV generation unit applied in UPS system can make the system more environmentally friendly. Because of the fluctuations and randomness of the output of photovoltaic power, how to make photovoltaic cells suitable for the characteristics of Super UPS and how to design the power regulation to increase its efficency are issues worth discussion. Aiming at such applications, conventional variable step MPPT algorithm is improved and a variable step LPPT algorithm is proposed to track faster, which are applied in Super UPS system.Chapter 1 gives the photovoltaic cell model and introduces an engineering calculation method of the PV array output characteristics, compares several commonly used MPPT algorithms, discusses their strengths and weaknesses, finally analyzes the need of PV power generation unit applied in Super UPS.Chapter 2 gives a detailed analysis of the variable step size maximum power point tracking (MPPT) algorithm. From the point of view of the convergence of the algorithm, the main problems of the conventional variable step algorithm are analyzed;an improved variable step tracking algorithm is proposed. The final experimental results show that the improved variable step algorithm has a higher tracking speed when having the same tracking accuracy.Chapter 3 introduces the operating mode of PV power generation unit and mainly analyses the variable step size limited power point tracking (LPPT) algorithm. According to the state of the grid, the energy flow of PV Power generation in super UPS is discussed. Finally, the feasibility of the power regulation method is verified by the mode switching experiments of PV unit coordinating with other sources under different states.At last the summary of the research work is made and the future work and further development are given.