| Wind energy is one of the most important renewable energy, and wind power is very significant to improve energy structure as well to promote the development of ecology and environment worldwide. Because of the merits of small investment and flexible application, small wind power generation system is very suitable to solve electricity supply problem in those areas where the housing is relatively dispersed and wind resource is rich, and it has broad market prospects. Although a large number of small wind power generation systems have been used at home and abroad, its low efficiency and poor reliability have directly restricted the promotion and development of small wind power system. The idea of energy management integrated control is introduced to the small wind power system in this thesis, which is based on the analysis of its working principle, energy flow, working mode transition. Its mathematic modeling, simulation and experiment are carried out to achieve the optimal and reliable operation of small wind power system.Firstly, the significance of wind power and the history of wind energy application as well wind power are outlined. The present status and development trends of small wind power in United States, Canada, Europe and China are overviewed. The application state and existed problems are also summarized. In addition, the domestic and oversea research status of small wind power systems is summed up.Secondly, in order to improve reliability and upgrade energy conversion efficiency, the configuration of small wind power generation system in which fixed pitch wind turbine with folding tail vane directly drives permanent magnet synchronous generator is adopted. Furthermore, a DC/DC converter is inserted between generator and load to adjust power output of wind turbine, and mechanical folding tail vane together with dump resistance is used to protect wind turbine from overspeed. The operating principle of small wind power generation system and the characteristics of wind turbine are also introduced. In addition, the principle of impedance transformation of DC / DC converter and the ways to achieve maximum power tracking control and load tracking control by means of DC / DC converters are given.Thirdly, the characteristic analysis of conventional small wind power system shows that lack of power regulation and unreasonable match between wind turbine and generator are the main reasons of low efficiency, and the uncontrolled charge and discharge current leads to early battery damage. The idea of energy management integrated control is introduced to the small wind power system to achieve its optimal and reliable operation by its inner energy transformation, energy flow as well as component safety detection and control. Energy flow, working modes and transition condition of various working modes of small wind power system are analyzed, and the transition diagram of its various working modes is established.Fourthly, after the principle to obtain maximum power tracking control is introduced, a control strategy without both wind speed sensors and rotation speed sensors in which the rotation speed of generator is indirectly controlled according to optimum power set is put forward to achieve maximum power energy output at or below nominal wind speed. According to the non-linear and time-varying characteristics of small wind power generation system, a self-regulation fuzzy PID type controller is designed to implement power control.Fifthly, the characteristics of lead-acid battery are briefly summarized and various factors to impact on battery life are analyzed. Combined fast charging principles of battery with the characteristics of wind power generation system, a fast charge control method which applies different charge rate at different phase, and a discharge control strategy which use voltage backlash with current compensation are put forward. The fast charge control with variable current can make battery to swiftly store energy and avoid overcharge. The voltage backlash discharge control with current compensation can also ensure battery to release the same amount of energy at different discharge rate.Sixthly, the component mathematical model of small wind power generation system is established. Because small wind power system with energy management integrated control is a hybrid system with discrete and continuous subsystem, Stateflow is used to achieve the logic control of working state transition. MATLAB-based simulation model is established for small wind power generation system, and simulation results on its maximum power tracking control, load tracking control and battery charge and discharge control verify the correctness and feasibility of energy management integrated control of small wind power generation system.Finally, an intelligent controller with energy management integrated control for small wind power system is designed and implemented. A Buck converter is employed as main power circuit to achieve energy regulation, and single-chip microcomputer C8051F410 is used as control unit. An experimental platform for small wind power generation system is built up in laboratory to test the performance of intelligent controller. Experiment results show the controller can automatically switch between different working modes according to wind speed, load and battery status to maintain system energy balance. The small wind power generation system with energy management integrated control can make full use of the output power of wind turbine and ensure battery reasonable charge and discharge at the same time. The experimental results further confirm the correctness and rationality of energy management integrated control, and provide practical guidance for application of intelligent controller with energy management integrated control.
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