Research On The Pitch Control Using PSS In The Wind Farm Based On Asynchronous Induction Generator

The development of human society is closely related to the exploitation and theutilization of the energy, and the development of new energy produces a leap in theeconomic development of the human every time. The energy structure of the world isalso currently pregnant with a significant change from fossil energy system to thesustainable energy system based on renewable energy. Wind energy is the fastestgrowing, the most widely used and the most economically applicable one comparedwith the other forms of energy.Compared to other generators, asynchronous induction generators have thecharacteristics of simple structure, reliable operation, high efficiency, low cost andgood endurance. Meanwhile they are easy to be manufactured. When theasynchronous induction generators run, the rotors are at a speed that is substantiallyconstant. So they are referred to as Fixed Speed Induction Generators (FSIGS). Ithas been studied that such FSIG-based wind farms can provide a contribution tonetwork damping.Firstly, this paper introduces the background and significance of the topicselection, a mathematical model of asynchronous induction based on wind farm isestablished and the mechanism of the oscillation modes generated the asynchronousinduction wind turbines by the system disturbance and its system oscillation modesand damping characteristics under the disturbance are analyzed by the characteristicsroots of the small-signal model. Secondly, the principle and design method of thepower system stabilizer (PSS) are studied in this paper, through application of thecompensation characteristic of the PSS to the asynchronous induction windgenerator propeller pitch angle control system that is introduced in the system, andan auxiliary pitch angle is used to improve the pitch angle control system. Its validityis verified by eigenvalue analysis of the system and time-domain simulation inMatlab/Simulink, and the results show that the pitch control using PSS caneffectively restrain the power oscillation of the system, improve the system dampingand enhance the dynamic stability of the system.