Study On Power Control And Energy Scheduling Of Wind-PV Hybrid Power System

At present,the energy used by countries all over the world is still dominated by traditional energy.The massive exploitation and overuse of fossil fuels not only cause energy shortages,but also cause serious pollution to the ecological environment.It is imminent to develop and utilize renewable clean energy.And the technology of wind power generation and photovoltaic power generation is relatively mature,which has become a hot research field and is widely favored.This dissertation takes the small-scale independent wind-storage hybrid power generation system as the research object,and discusses the overall composition,working principle and control strategy of the system.On the basis of the energy conversion mechanism and working principle of wind turbine and photovoltaic components,the simulation model of wind turbine and photovoltaic components is set up,and different simulation conditions are set up to explore its output characteristics.According to the output characteristics of the system,power optimization control and energy dispatching schemes for wind power generation system and photovoltaic power generation system are proposed to improve the power output and power quality.The specific research contents are as follows:(1)The variable step size disturbance observation method is used to track the maximum power of the wind turbine.The large step length disturbance is adopted at the maximum power point,and the small step length is used to disturb the maximum power point.On the method,the response speed and the stability precision of the power output can meet the requirements.A control strategy is proposed to improve the maximum power output of photovoltaic modules by using the improved fuzzy control to optimize the Boost circuit.The input and membership function of the fuzzy controller and the segmentation of membership functions are optimized and improved.The simulation examples show that the power optimization control methods proposed in this paper are higher than the traditional improved disturbance observation method in control accuracy and response speed.(2)The system adds energy storage devices to complete energy scheduling.Considering the influencing factors and real-time operating characteristics of the battery in the energy storage system,the third-order dynamic simulation model of the lead-acid battery was built in the simulink environment,and the accuracy of the model was verified by experimental data.According to MASS intelligent charging control theory,the battery charging current is controlled based on BP neural network algorithm.Compared with the stage charging mode,the charging current is optimized and the efficiency is improved obviously.(3)Sixteen different working conditions of the system are analyzed.The finite state machine theory is used to schedule the energy of the system so that the system energy can be reasonably distributed in different states and in the same state.The simulation model of the whole system is established in matlab/simulink.The simulation results verify that the control scheme in this dissertation can complete the energy dispatch under different working conditions of the system and maintain the stability of the bus voltage,then the power quality is improved.