Patent ID: 7245054

Claim:
A permanent magnet electric machine comprising: a stator having twelve stator slots; and a rotor including ten rotor poles and n axial rotor sections with permanent magnets, wherein said permanent magnets have a rectangular cross section, wherein n is greater than one and said n axial rotor sections are rotationally offset by an offset angle equal to a cogging angle divided by n, said cogging angle being equal to 360 degrees divided by the least common multiple of the number of the stator slots and the number of the rotor poles, and wherein said permanent magnets in each of said n axial rotor sections have substantially the same circumferential length, wherein a width of each of said twelve stator slots is greater than an edge gap defined as a distance between a radially outer surface of each of said permanent magnets and a radially inner surface of said stator taken along a radial line of said rotor, wherein said permanent magnet electric machine has n cogging torque waveforms that are substantially sinusoidally-shaped and that are associated with said axial rotor sections, and wherein said cogging torque waveforms substantially cancel.