Research On On - Line Monitoring And Control Technology Of Three - Phase Photovoltaic Power Generation System

With the global economic growth and the improvement of people’s living standard, the energy shortage and environmental pollution problems have become increasingly prominent and have received much attention. Therefore, people try to find new non-polluting energy in a variety of ways to replace the traditional fossil energy gradually. Currently, some of the developments and utilizations of new energies such as wind, solar, biomass, ocean energy, etc. have become a research focus of scholars. In particular, solar energy is infinite and pollution-free and it also has some other advantages so that it became a focus of research in the field of new energy. Therefore, the maximum power point tracking (MPPT), inverter control, online monitoring and other related technologies is in-depth studied for photovoltaic power generation system in this article. The main research contents are as follows:Firstly, on the tracking of multi-peak maximum power point of PV power generation system, considering the problems that the tracking time of Disturbance Observation Method is long and the large disturbance of Particle Swarm Optimization and other problems, a maximum power point tracking algorithm based on simulated annealing particle swarm optimization is proposed. The velocity shrinkage factor of particle and disturbance of Roulette strategy of optimal particle are introduced in the MPPT algorithm, thus this algorithm avoids the local maximum power effectively and tracks to the global maximum power fast, ensuring the dynamic response and steady state accuracy of the PV power system under conditions that the light intensity and temperature changes. Meanwhile, a simulation model is built based on Matlab/Simulink simulation platform. Comparing with the three kinds of maximum power point tracking algorithms in PV power system through simulation research, the results show that the proposed method has better real-time performance and better robustness.Secondly, in the inverter control, to stabilize the output voltage of the inverter and achieve unit power factor control of the load side, use double-loop control method of a three-phase voltage SVPWM inverter and write the control program of the method. For the problem that the LC filter cannot suppress harmonic well. By calculating, a low-pass filter of LCL type is analyzed and designed theoretically, thus effectively suppress higher harmonics that is generated by the inverter.Finally, three-phase photovoltaic system experiment platform is built which takes TMS320F2812chip as the core. Design with EPM570T100and CY7C68013as the auxiliary processor, LabVIEW platform for the development of online monitoring PC.Debug the system according to different grades, get the calibration data of sensor, test waveforms of DC/DC circuit, test waveforms of DC/DC inverter circuit and test results of online monitoring system given in this paper, then the rationality of design is verified by experiments.