Research On Control Method Of Maximum Power Point Tracking In Solar Photovoltaic Power System

With the rapid development of human civilization and social progress. Tradinational fossil energy resources have been unable to meet the growing needs of human beings. Continuous development and utilization of new energy sources, we can protect the environment for human survival, sustainable development. Since the solar energy resources are very abundant, clean and renewable, without pollution, so much attention. The direct way of using solar energy is photovoltaic power generation. However, under partially shaded conditions, multiple local maximum can be exhibited on the power-voltage characteristic curve, the work point can not work at the maximum power point, this will cause the system output efficiency can not reach the maximum. Therefore, study on MPPT method of solar photovoltaic power generation system is very important.Beginning from the theory of solar photovoltaic power generation system, introduces the composition and basic types of solar photovoltaic power generation system. Based on the detailed analysis of the working principle, the solar photovoltaic battery equivalent circuit and output characteristics, this thesis gives comparison and discussion of four eommonly used MPP method, they are Constant Voltage Tracking (CVT) method, Perturbation and Observation (P&O) method, Incremental Conductance (INC) method and Particle Swarm optimization (PSO) method. Analyzing the working principle, advantages and disadvantages of different methods of MPPT, a control algorithm based on Particle Swarm Optimization algorithm using fuzzy control was proposed. Fuzzy controller was used to optimize the inertia weight ω of PSO algorithm to ensure that the system has better dynamic response speed and steady-state accuracy when solar radiation is changing. Simulation were performed with the PSO method and Fuzzy PSO method on the same condition, and the results indicate that the proposed global MPPT algorithm can fast and accurately track the global maximum under partially shaded conditions.Based on the theory, this thesis gives a detailed introduction on the hardware and the software design of MPPT control system of solar photovoltaic power generation system. The maximum power point tracking control system based on TMS320F28335 DSP chip as the control core. Hardware circuit design is comprised of main circuit, driving circuit and protection circuit of the MOSFET, DSP minimum system, DC signal conditioning circuit and serial communication circuit etc. Hardware circuit design is comprised of main program, interrupt program and A/D conversion program etc.