Abstract: A rotary position sensor featuring a magnetized rotor which produces a magnetic flux density that varies sinusoidally with respect to the angular position of the rotor, which may be either a selectively magnetized ring or disk. The magnetic flux density produced by the rotor is measured by a sensor that responds in a linear fashion to the magnitude of the radial component of the magnetic flux density. Typical embodiments would use magnetic flux density sensors, as for example either linear Hall sensors or magnetoresistive type sensors. The measured magnetic flux densities are then used as in a traditional resolver to compute position or used to directly generate control signals to operate, for example, a motor.

Abstract: Disclosed is an electric motor system with reduced torque ripple comprising a sinusoidally magnetized permanent magnet, a sinusoidal inverter, a higher resolution position sensor, a composite iron stator yoke, a composite reinforced plastic rotor core and shaft; and a high gear ratio gear reduction box. The novel combination of magnet, inverter, sensor, plastic rotor core and shaft and high gear ratio gear box substantially reduces the torque ripple on the shaft of said motor system.

Abstract: A voltage mode control method and apparatus for extending speed range operation from a sinusoidally excited permanent magnet motor is described. The method includes a determination of a maximum value from a first set of parameters with each parameter having a known maximum value as well as a reading of a second set of parameters. A computation of a first derived angle using the first set of parameters and the second set of parameters is then performed. A computation of amplitude of phase voltage and a second derived angle using the first derived angle follows. A resultant output comprising a set of derived command voltages for controlling a power circuit is created whereby the power circuit can achieve required torque levels with lower currents for power switches.

Abstract: A method and an apparatus using the method that generates an index pulse which includes firstly the generation of a first electronic signal which includes a first level and a second level based upon a multiphase sinusoidal motor control circuit. Secondly, the generation of at least a second electronic signal that includes a first level and a second level based upon a multiphase sinusoidal motor control circuit wherein the first electronic signal and the second electronic signal are levelly spaced apart based upon the phase number of the multiphase sinusoidal motor control circuit wherein a set difference in level exists for a first specified period between the first and said the signal. Thirdly, the determination of the index pulse based upon a transition from the first level to the second level of the first electronic signal.