| In recent years, micro-grid technologies for the integration of a variety of distributed power and storage devices became one of the latest topics in the field of electrical engineering research at home and abroad, especially the wind-solar-storage had got a lot of attentions. The wind-solar-storage micro-grid can overcome to some extent the defects of the output of distributed power, including randomness and intermittence, improve energy efficiency, which supplies power to the load by a wind power generation system, a photovoltaic cell and a storage battery. However, the micro-grid solved the problem of traditional power generation, also need to overcome the inherent problem at the same time, for example, the power quality and the reliability of the distribution network will be affected when the micro-grid is connected to electricity grid. Therefore, a reasonable and reliable control strategy of micro-grid has important theoretical significance and application value.On the basis of the theory of the micro-grid system, this thesis introduced the fuzzy adaptive PID controller. The simulation platform was built, and the simulation results are analyzed to verify the correctness and effectiveness of the new controller.This thesis mainly includes the following contents:(1) The control principle of the inverter, the micro power PQ control method and V/f control method were studied. Aiming at the insufficient of PI controller, a fuzzy inference technique was proposed to optimize the parameters of the control method. The simulation model was built in MATLAB/Simulink, and simulation analysis was carried out for a single micro power using PI control and fuzzy adaptive control, and the effectiveness of the fuzzy adaptive controller was proved.(2) The mathematical models of three kinds of micro power of wind turbine, photovoltaic cells and storage battery were established, and different control strategies were selected according to the characteristics of the micro source. Finally, the simulation model was established. In the model, the active power of wind turbine and photovoltaic cells was obtained by the maximum power tracking, which ensured the effective use of renewable energy. The storage battery with constant voltage and frequency control was used for supporting voltage and frequency.(3) This thesis built wind-solar-storage system simulation model, and simulated and analyzed the operating characteristics of the system under different conditions. According to the simulation result, system using fuzzy adaptive controller could realize power balance and the stability of voltage and frequency, which verified the feasibility of the controller.Based on the Northeast Company of China Power Investment Corporation project for the research on economic operation of wind farms, the wind-solar-storage micro-grid control strategies were researched deeply for making some contribution to the development of inverter control technology. |
PDF Full Text Request