The principle and harmonic analysis of a new BDFM with tooth harmonic wound rotor using as a generator

This paper presents the principle of a new rotor of Brushless Doubly-Fed Machine (BDFM) - the tooth harmonic wound rotor. The rotor could be easily coupled with both stator windings because of its high winding factor for both pole-pairs. Given the current of control winding, the harmonic analysis in space is presented. The result shows that some of the special harmonic waves, which deteriorate the waveform of induced voltage in power winding, would be produced. The measured induced voltage in power winding is given and the FFT is used to disclose the components, which validate the harmonic analysis. The results show that a wave filter should be used in the control winding to inhibit the higher harmonic components caused by PWM inverter.