A Study On Doubly Fed Variable Speed Salient Pole Synchronous Generator And Its Excitation System

Doubly fed salient pole synchronous generator has many excellent characteristics include variable speed constant frequency, it can improve the stability of power system, it can not lose step even when operated in deep lead phase, so it is especially adapted to use as wind power generators and pumped-storage hydraulic power plant. As a new kind of AC excited generator, doubly fed salient pole synchronous machine adopt split salient pole and orthogonal winding. Therefore, it can be used in great power plant. Variable frequency converter is be connected rotor supplies the excitation winding. Its excellent characteristics mostly depend on the vector control system. Firstly, the fundamental principle of doubly fed variable speed salient pole synchronous machine is generalized. The mathematical model in the synchronous reference frame is also established, and it will be the base of the research. The operation characteristic of the machine is analyzed. It shows that AC excitation capacity of induction motor depends on slip of electric machines. With the variable speed of rotor, tracing maximal wind energy and optimum load regulation will be possible. Then stator flux oriented control is used to control active and reactive power of the machine.A four quadrant PWM convert which energy can flux by reversible orientation is researched. Based on this theory, We can research and develop a control system used DSP chip which can control this PWM convert. The simulation model is built on the software package of MATLAB/SIMULINK, and the simulation results indicate the validity of the excitation control system of the doubly fed variable speed salient pole synchronous machine.