Excitation control system of DFIG connected to the grid on the basis of similar signals from rotor

This paper presents a novel technique for the excitation control of the doubly-fed induction generator (DFIG) connected to the grid basing on the rotor similar signal method. That is using the similar signals from rotor of a small capacity doubly-fed induction machine (DFIM) as a base to generate the signal for the excitation control of DFIG. Based on this method, all stages in system are very simple; and the active power and the reactive power of DFIG supplied to the grid will be controlled separately. The active power is in proportion to the coefficient K_p and the reactive power is in proportion to the coefficient K_q, so we can independently control the reactive power and the reactive power of DFIG fed into the grid by adjusting the value of K_q and K_q, so it is easy to control the system. Although the simple controllers such as PI controllers are used to control the power system, the quality of the system is high. In summary, the advantage of this method is that system is simple but still effective.