Hybridisation ratio for hybrid excitation synchronous motors in electric vehicles with enhanced performance

For electric vehicles (EVs) with severe acceleration requirement, the selected motor would be inevitably overdesigned to meet the acceleration requirement. To address this, the motor constant power speed ratio (CPSR) should be increased to remove part of the overdesign. There are different flux weakening techniques that are used to increase motor maximum speed (and increase the CPSR). Among them, hybrid excitation synchronous motor (HESM) advantages have been benefited in this study. CPSR depends on hybridisation ratio (HR) of the excitation system, and the motor inductance. The relation is analytically derived in this study. In addition to increasing CPSR, HR can control the place of motor high-efficient area over the efficiency map, which can increase EV total efficiency. A search algorithm has been developed, here, to find the optimal HR of a non-optimal HESM. The final design gives an efficient motor performance with less overdesign in drivetrain. Compared with the original permanent magnet synchronous motor, 4.1% improvement in total efficiency for an average city-highway driving cycle has been achieved, and 16% decrease in rated values of drivetrain elements is obtained.


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  • Accession Number: 01663855
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 15 2018 4:07PM