A Comparison of the Wound Rotor and Nested-Loop Rotor Brushless Doubly Fed Generator

Both the wound rotor and the nested-loop rotor can realize the coupling with the power winding (PW) and control winding. And the two types of rotors in a brushless doubly fed generator (BDFG) can realize variable-speed, constant-frequency generation. In this paper, the two types BDFG are compared through finite element analysis and experiments. From the finite element simulation results, it can be seen that the air gap flux density harmonic contents, PW line voltage harmonic contents, and the core loss of the nested-loop rotor BDFG are higher than those of the wound-rotor BDFG. In the experiments, the efficiency of the wound rotor BDFG is slightly lower than that of the nested-loop rotor BDFG when the rotor speed is below the natural synchronous speed and is much higher than that of the nested-loop rotor BDFG when the rotor speed is above the natural synchronous speed. (C) 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.