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

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.

Estimation of the main dimensions of the traction permanent magnet-assisted synchronous reluctance motor

“…To ensure the strength of the rotor structure, it is necessary that the ferromagnetic segments are internally connected to each other, so the rotor structure uses tangential ribs near the air gap with thickness W r [14]. Due to the installation of permanent magnets, the tangential ribs are saturated during normal operation of the motor and therefore magnetically insulate various steel segments [14]. From the point of view of creating torque, the scattering of the flux caused by tangential ribs should be minimal [11].…”

“…A review of publications [10][11][12][13][14] shows that the determination of the dimensions and parameters of electric motors is carried out by numerical field calculations in combination with multicriteria optimization. The varied parameters are usually the geometric dimensions of the elements of the magnetic core.…”

Single‐phase direct‐on‐line synchronous motor for a specific application in comparison with an induction motor

“…In this study, the number of flux barriers is fixed as four for all rotor structures. The reason is the magnetic saliency is not changed considerably with a flux barrier number greater than four, the average torque is also constant and torque ripple is also minimum for four flux barrier …”

Design of Outer-Rotor Permanent-Magnet-Assisted Synchronous Reluctance Motor for Electric Vehicles

“…The rotor topology of PMaSynRM is achieved by placing PMs on the rotor flux barriers of the SynRM, thus indirectly increasing the difference between the inductances of this machine [12]. Maximum performance is obtained in PMaSynRM when maximum L d and minimum L q are obtained in the geometric design of the rotor of PMaSynRM.…”

“…These torques depend on the flux barrier shapes in the rotor topology. Flux barrier shapes can be arc-shaped or rectangular [12].…”