Design and Analysis of Line-Start Synchronous Reluctance Motor Considering the Maximum Inertia and Power Factor

In this paper, the design and analysis of a 7.5 kW 4 poles line-start synchronous reluctance motor (LS-SynRM) are investigated by considering the maximum inertia and power factor. Since the LS-SynRM must operate at synchronous speed, the synchronization capability, determined by the system inertia, is a crucial performance parameter for various industrial applications. Electromagnetic and mechanical transient analysis of a finite element analysis (FEA) are performed to analyze the maximum inertia under the condition of 380 V--60 Hz voltage. The initial model is designed by considering the maximum inertia. Moreover, the power factor is also important performance index in industrial applications according to IEC 60034-1. Therefore, a bridge design is proposed based on the initial model, and the improved model is designed by considering the efficiency, power factor, and mechanical stress. To improve the efficiency and power factor, the barrier optimal model is designed based on the improved model. Finally, the barrier optimal model of 7.5 kW 4 poles LS-SynRM is manufactured, and experiments are performed to verify the steady-state and starting performance. In the steady-state performance, the efficiency and power factor of LS-SynRM are 93.89% (>92.6% IE4) and 78.1 (>78% IEC 60034-1), respectively. It showed about a 1.59%p higher efficiency than that of IM with IE3 efficiency.