Theoretical and Experimental Analysis of Electromagnetic Force Waves for Rotor Magnetic Shunt Hybrid Excitation Synchronous Motor

The analysis of electromagnetic (EM) force waves in rotor magnetic shunt hybrid excitation synchronous motor (RMS-HESM) under direct current (dc) excitation has received limited attention from researchers, despite its crucial importance for the electric vehicle industry and significant role in optimizing noise, vibration, and harshness design. This article investigates the EM force waves analysis of RMS-HESM under dc excitation across multiple operating conditions in detail. First, the fundamental structure of the RMS-HESM was briefly introduced, and an equivalent magnetic circuit model was established to consider changes in dc excitation. The radial EM force wave was then theoretically analyzed, with qualitative determination of its source, frequency and order that greatly influence the EM force vibration of the RMS-HESM. Subsequently, 3-D finite element simulation was used to obtain the radial EM force wave under different operating conditions when applying dc excitation. The component of the radial EM force wave that is significantly affected by changes in excitation current was analyzed and discussed for its causes. Finally, an RMS-HESM prototype experimental platform was built to measure the vibration characteristics of the motor through sensors and verify the simulation and analysis of radial EM force waves.