Research On MPPT Control Strategy Of Photovoltaic Power Generation System

With the growing of environmental pollution, depletion of fossil fuels and other issues, the development of renewable energy had became an inevitable trend. Solar energy as an emerging renewable energy getting more and more attentions of people for its advantages of less pollution and large reserves. Including, solar photovoltaic power generation was an important form of solar energy utilization, it’s a power mode converting light energy into electrical energy by the use of solar photovoltaic cells then stored in batteries or fed into the grid supplying the users. However, the use of photovoltaic cells in photovoltaic power generation system susceptible to the external environment made lower utilization, thus it was quite necessary to track control maximum power point of photovoltaic cells.Photovoltaic power generation system structure was varied, the paper described the classifications of photovoltaic systems and analyzed its typical topological structure. The Boost circuit realized MPPT algorithm was presented in this paper according to compare the advantages and disadvantages of the common DC/DC converter circuit. By analyzed the equivalent circuit of a photovoltaic cell, the utilization of photovoltaic cells not only related to the internal characteristics of photovoltaic cells but also affected by light, Realized MPPT tracking control by the combination works of Boost circuit.The paper carried on the detailed analysis of several common used maximum power point tracking algorithm such as variable step disturbance observer method, hysteresis comparative law and interpolation method on the analysis of solar photovoltaic cells model. Proposed improved algorithms for its advantages and disadvantages called calculation method based on the difference combined with variable step hysteresis method. Compared with improved algorithms for comparison in simulation environment of MATLAB/Simulink. The simulation results showed the improved algorithm was more speed and stability.The paper designed maximum power point tracking control hardware and software parts of photovoltaic system, which regarded DSP control chip TMS320F28335 as the core according to the theoretical analysis. Hardware circuit consisted of protective circuit, drive circuit, Boost main circuit and DC current, voltage sampling processing circuit. The software included the main program process designing, sampling part designing and interrupt subroutine process designing, whose detailed design had been introduced in this paper.Through built photovoltaic system experiment platform, analized the main circuit of hardware, designed the control software of system, test a 500 W prototype, test achieved the desired objectives.