Comparison of copper loss minimization and field current minimization for Electrically Excited Synchronous Motor in mild hybrid drives

Electrically Excited Synchronous Motor (EESM) serves as an option on hybrid vehicle applications. An EESM for mild hybrid application is designed in this study. Copper loss minimization and field current minimization are analyzed for current control strategies of EESM. Both of the current control strategies are applied and comparisons between the two are made thereafter. In both of the strategies, high efficiency is achieved in the high speed region whereas high power factor is achieved in the high torque region. Copper loss minimization gives a larger operation area of high efficiency and high power factor, whereas the rotor heat generation can be reduced when field current minimization is applied.