Research on maximal power tracking control for brushless doubly-fed wind power generator based on DTC

In order to implement the maximal power tracking control of brushless doubly-fed wind power generation system, direct torque control (DTC) is adopted based on the power output characteristics of wind turbine. And for the problem of the bad robustness of flux observation as brushless doubly-fed generator (BDFG) running at lower excitation current frequency of control winding side, a sliding mode flux observer is designed. The switching function in common sliding mode observer is replaced by a continuous function to weaken the chattering. Through simulation and experiment comparison with the operation performance of DTC system based on u-i flux model back EMF integral algorithm, it can be seen that the designed flux observer can enhance the accuracy of flux estimation and can effectively improve the operation performance of DTC system as the frequency of BDFG control winding side is lower.