The Research On Control System Of Doubly-Fed VSCF Wind Power Generator

With the development of society and advance of technology, the function and position of energy is more and more outstanding in the society, economic development and the increasing of live quantity. Seeing from a development of the farsighted strategy of energy, man must look for the road to cleanly energy. Wind energy is a conversional form of solar energy, which can't be used up. During the process of switching electrical energy, it doesn't produce any bad gas and waste and also doesn't pollute circumstance; it has the characteristics of using local materials and not requiring transportation, therefore, it is widely regarded by many governments in the world. Our country also begins to greatly exploit resources of wind energy.Just based on the two points mentioned above, a control system of doubly-fed variable speed constant frequency (VSCF) wind power generator based on 8XC196MC is designed in this paper, which can smoothly transform between the different operational modes from sub-synchronous speed to synchronous speed and to super-synchronous speed. When the system is working, the photoelectric coder checks the speed of doubly-fed VSCF wind power generator; according as the principle formula of VSCF, the excitation current frequency of rotor is calculated to satisfy the aim of VSCF control. When generator runs at conversation states from synchronous speed to super-synchronous speed, the excitation current of oppositional phase sequence should ensure the current waveform smoothly transform.This paper begins with the theory of VSCF, the theoretical analysis is deeply carried out in detail and the control strategy id studied. Then, the main circuit used IGBT module and its driver circuit, protect circuit and its control circuit are designed in accordance with the characteristic of control system of doubly-fed VSCF wind power generator. The internal waveform generator of 8XC196MC can generate three-pair and two-way independent SPWM waveforms to control six IGBTs' on-off with the intention of feeding-in sine waveform currentto the rotor of generator. Next, the control technique and arithmetic of doubly-fed VSCF wind power generator are also studied in detail, including some of author's sights.Finally, a large number of experiments are done in this paper, such as the experiments of constant voltage and constant frequency, the current waveform of rotor, different carried-wave ratio, the transition smoothly and connecting electricity web etc. The theoretics and experiments results show that the design of control system is rational, terse and steady; the analysis of control strategy and system experiments are successful basically. However, the control technology of the doubly-fed VSCF wind power generator system is rather complicated, some of difficulties and emphases should be perfected in the future.