Line-Start Permanent-Magnet Synchronous Motor versus Induction Motor: Technical, Environmental and Economical Considerations

This paper presents an explicit comparison of the three-phase line-start permanent-magnet synchronous (LSPM) motor with the squirrel-cage induction motor (IM). It investigates the effect of number of rotor bars on the performance of the motors by considering two alternative options including 32 and 45 rotor bars. Finite-element analysis is utilized for design and performance prediction of the studied motors. Both steady-state and dynamic responses of the motors under no-load, constant load, fan load, and step load are investigated. The simulation results confirm that the LSPM motor with 32 rotor bars can remain stable at constant speed when operating in overloaded and variable voltage conditions. The LSPM motor has advantages of high efficiency and high power factor while IM has superior dynamic performance.