Loss minimisation strategy for DFIG in wind turbine considering iron losses

Nowadays doubly fed induction generator (DFIG) is the mainly used generator in wind power generation, and several efforts are being made to tackle the issues related to their high production costs. In order to solve this problem, this work presents an optimized control strategy that seeks to mitigate the electrical losses inside the generator. The control strategy is based on the optimal reactive power sharing between the rotor and stator circuits of the generator connected to a back-to-back power electronic converter (PEC). In this paper the iron losses, which are traditionally ignored in machine models and vector controls, are considered to achieve better performance. Moreover, since the loss minimisation strategy requires different converter operation points, a numerical model for calculating the semiconductor power losses is shown to evaluate whether this strategy compromises the system losses. Simulation results for a 7.5 kW DFIG show the amount of power saved when the loss minimisation control is applied.