Patent ID: 6133662
Filing Date: 2000-10-17
Classification: H02K,Y02T

Abstract:
A permanent magnet electric machine comprising:a stator provided with windings thereon; anda rotor disposed with an air gap between the stator and the rotor, and having a plurality of permanent magnets embedded along a circumference thereof, with spacing between adjacent magnets; whereina circumferential extent of surfaces of the permanent magnets facing the stator is selected so that an induced voltage in the machine has a waveform which approximates a sinusoidal waveform; andan angle .theta. whose sides are radii of the rotor passing through opposite circumferential ends of a surface of each permanent magnet facing the stator satisfies one of the expressions:.theta..apprxeq.n.times..tau..sub.s +.alpha.,.theta..apprxeq.n.times..tau..sub.s +.beta.;.theta..apprxeq.n.times..tau..sub.s +.gamma.where n is a natural number, .tau..sub.s is a slot pitch of slots in the stator, .alpha. is an angle formed by a tooth, of the stator, .beta. is an angle formed by a slot of the stator, and .gamma. is an angle formed by an opening of each slot.