An Improved Brushless Doubly Fed Generator With Interior PM Rotor for Wind Power Applications

This paper presents a novel interior permanent magnet brushless doubly fed generator (IPM-BDFG) for wind power applications, which is based on the magnetic field modulation theory. The basic structure and working principle of the IPM-BDFG are put forward first. As the rotor structure has a great influence on the performance of the IPM-BDFG, the merits of the IPM rotor are discussed by comparing with the surface-mounted rotor. In order to solve the asymmetry phenomena and reduce the harmonics caused by the introduction of field modulation ring, a three-segmented structure for the outer rotor is adopted. Finally, the performances of the proposed IPM-BDFG are validated by using finite-element analysis (FEA). The FEA results show that the IPM-BDFG with segmented outer rotor has excellent performances and owns good potential in the applications of future large-scale wind power generation systems.