Optimum design and operation analysis of permanent magnet-assisted synchronous reluctance motor

Authors: JAMAL DEHGHANI ASHKEZARI, HASSAN KHAJEROSHANAEE, MOHSEN NIASATI, MOHAMMAD JAFAR MOJIBIAN

Abstract: This paper presents an optimum design process and operational analysis of a permanent magnet-assisted synchronous reluctance motor (PMASynRM) as a low-cost and highly efficient consumed magnet material machine. The motor's topology is based on inserting partial permanent magnetic materials into flux barriers of an original synchronous reluctance motor (SynRM) that implicitly increase the difference between the machine's inductances, thereby increasing output torque. The procedure of rotor design as the main contribution of this paper is carefully illustrated. The rectangular shape of the flux barriers was found to achieve cost reduction and improve productivity. The impact of the permanent magnet added to the rectangular flux barriers and how it decreases the q-axis flux are described. For analytical studies, the optimum structure of a sample machine for high-power application is designed through the 2D finite element method in a Maxwell environment. For the sample machine, it is shown that the optimum number of flux barriers, optimum insulation ratio, and optimum width of permanent magnets in order to maintain the rating level of output and minimize the ripple are 4, 0.375, and 30 mm, respectively. In addition to demonstrating the operation of the motor with and without permanent magnet material, the performance of the hybrid motor is evaluated with two different permanent magnet materials, ferrite and NdFeB. Simulation results show that despite a negligible rise of ripple torque, the PMASynRM is able to achieve a higher output torque than the original SynRM with a low amount of permanent magnet material.

Keywords: Electrical motor, permanent magnet-assisted synchronous reluctance motor, machine design, finite element method, Maxwell

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