Research On An Optimal Speed Control Arithmetic In Wind Energy Generation System

With the capability of wind generating systems constantly increasing, it is more and more important to improve the efficiency of the wind generator system in the research of wind energy generation system. Variable speed and constant frequency (VSCF) system becomes hot point in the wind energy generation system and this control of doubly-oriented converter is key core in the doubly-fed generating system.In order to capture the maximal wind power, this dissertation mainly researches a control arithmetic for doubly-oriented PWM converter. Firstly, the dissertation analyses the characteristic and maximal wind power capture principle of the wind turbine. Then, operation phases and modes of wind motor are ascertained in VSCF wind power conversion system. In order to realize this run mode, the doubly-oriented PWM converter is deep researched. The dissertation introduces a vector control strategy based on virtual line-flux-linkage-oriented of the power grid. The angle of the power grid voltage is ascertained by the estimation of virtual line-flux-linkage and then the control of pulse synchronization is realized. The initial value of the virtual line-flux-linkage is gained by inserting several zero voltages in starting the converter. This control strategy is verified by simulation. In the rotor side, the PWM convector is designed depending on the wind turbine and the doubly-fed generator model. To realize the maximal wind power tracing control, the dissertation brings forward a novel control strategy of rotor speed perturb and power observation and completely realizes the control of rotor speed. The dissertation researches and analyzes the rotor speed perturb amplitude and power observation method, and the method is verified by simulation. Finally, simulating experiment for the whole system is carried through with the stator flux-oriented vector strategy and control arithmetic of rotor speed perturb and power observation.The dissertation does deep research on doubly-oriented PWM converter—the core controller of VSCF in wind energy system applied with the doubly-fed generator, and presents a feasible control strategy for maximal wind power capture. In the end, the simulation software MATLAB/SIMULINK is used to verify that the system models are rightly built and control strategy is feasibjte. It has some reference value for further research and experiment.