Mahdi Shabani - Msc student,Jafar miii monfared, Amir kabir University of Technology
Mohammad Madani - Isfahan University of Technology

permanent magnet brushless ac (BLAC) motors are jnding expanded use in high-performance applications where torque smoothness is essential. This paper is focused on various magnet shape consideration that can be used in reducing the torque ripple of BLAC machines. The aper quantifies the various sources of torque ripple, which may be minimized by appropriate magnet shape design consideration. The paper discusses the effect of magnet shape on the cogging torque and harmonic content of the air-gap flux density. The eflect of magnetization, sint~soidal outer surface and magnet segmentation is investigated. A time-steppedfinite-element method is employed to evaltlate the cogging torque and air-gap jlux density. Injlzrence of magnet span on cogging torque in uniform thickness, bread loaf and arc shaped magnet is investigated In segmented magnet, effect of magnet blocks separation and the number of magnets are studied.

torque ripple, brushless ac machine, magnet shape, finite elemen