METHOD AND APPARATUS FOR TORQUE RIPPLE REDUCTION IN SINUSOIDALLY EXCITED BRUSHLESS PERMANENT MAGNET MOTORS

摘要

A method for determining a dimension in a motor is described. By applying Fourier analysis, a sequence of terms is obtained. Since the fifth harmonic is the most undesirable term, the minimization of the fifth harmonic term will make resultant waveform closer to sine wave. Based upon the above, a determination of an angle δ (22) is described, wherein the fifth harmonic term of the sequence of terms is minimized. An electronic motor having a rotor (26) and a set of slot on said rotor surface (36) having a set of magnets (46) with a width δ (22) along the circumference (30) of said rotor surface (36) is described., The width δ (22) is determined by a method that includes applying Fourier analysis thereby a sequence of terms is obtained. Since the fifth harmonic is the most undesirable term, the minimization of the fifth harmonic term will make resultant waveform closer to sine wave. Based upon the above, a determination of an angle δ (22) is described, wherein the fifth harmonic tem of the sequence of terms is minimized.