Influence of design parameters on the field current of the tooth harmonic excitation system

This study proposes a brushless hybrid excitation permanent magnet synchronous generator (HEPMSG) with rotor tooth harmonic winding. The rotor tooth harmonic electromotive force (EMF), induced by the inherent tooth harmonic magnetic field in the air gap, will provide the field current for the rotor field winding after the rectification. The structure and principle of the machine are introduced, and the generation mechanism of the rotor tooth harmonic EMF is analysed. The influence of design parameters on the rotor field current provided by the tooth harmonic excitation system is discussed. The performance of the tooth harmonic excitation is calculated and analysed for different design parameters including stator slot width, air-gap length, tooth harmonic winding turns, skewed stator slot and magnetic saturation, and the optimal design parameters of the HEPMSG are obtained. One HEPMSG prototype with rotor tooth harmonic winding was developed, and five different working conditions of the tooth harmonic excitation system were tested. The maximum field current is obtained by comparing the connection mode of the tooth harmonic winding.