Rotor optimisation design and performance comparison of BDFG for wind power generation

摘要

Doubly fed induction generators and permanent magnet synchronous generators are widely used in wind power generation system in recent years. However, they still have technological and economic penalties, which limit their applications in wind power generation. This study presents a novel brushless doubly fed generator (BDFG) with the hybrid rotor, which has several outstanding advantages, so as to penetrate into large-scale offshore wind power generation. In this study, the magnetic field modulation of the hybrid rotor is studied in detail. Owing to the decisive role of 'special rotor' on the performance of BDFG, the effect of main rotor structure parameters on coupling capacity is analysed based on Taguchi method, and the effect of assisted cage bars on the coupling capacity is also researched. The simulation models are simulated and analysed to compare the different exciting winding conditions. A 25.8 kW, 8/4 pole prototype BDFG with the hybrid rotor is manufactured to examine the performance of the proposed BDFG. Finally, the simulation and experiment results verify that the optimised rotor has stronger coupling capacity and the few-pole (i.e. 4-pole) winding should be used as control winding.