Abstract: An apparatus for measuring relative displacement between a first shaft and a second shaft includes first and second rotor assemblies. The first rotor assembly is coupled to the first shaft and is centered on an axis. The second rotor assembly is coupled to the second shaft. The second rotor assembly has first and second stator plates. Each of the first and second stator plates includes an upper surface and a lower surface. The upper and lower surfaces are parallel. The first and second stator plates include a plurality of teeth extending in a direction radial of the axis. The first and second stator plates form a gap between the lower surface of the first stator plate and the upper surface of the second stator plate. The apparatus further includes at least one magnet having a magnetic field and disposed on the first rotor assembly and a sensing device disposed within the gap for sensing a magnetic flux of the magnetic field.

Abstract: An apparatus for measuring relative displacement between a first shaft and a second shaft includes first and second rotor assemblies. The first rotor assembly is coupled to the first shaft and is centered on an axis. The second rotor assembly is coupled to the second shaft. The second rotor assembly has first and second stator plates. Each of the first and second stator plates includes an upper surface and a lower surface. The upper and lower surfaces are parallel. The first and second stator plates include a plurality of teeth extending in a direction radial of the axis. The first and second stator plates form a gap between the lower surface of the first stator plate and the upper surface of the second stator plate. The apparatus further includes at least one magnet having a magnetic field and disposed on the first rotor assembly and a sensing device disposed within the gap for sensing a magnetic flux of the magnetic field.

Abstract: Disclosed herein is a method for parameter identification in a switched reluctance electric machine comprising: operating the switched reluctance electric machine in response to a desired command; and measuring an actual operating characteristic of the switched reluctance electric machine. The method also includes: modeling the switched reluctance electric machine to formulate an estimated operating characteristic based on the desired command; comparing the actual operating characteristic and the estimated operating characteristic to formulate an error there between; and determining a parameter estimate for the switched reluctance machine based on the error and a previous parameter estimate.

Abstract: A variable reluctance rotational displacement sensor with: an annular sleeve; a coil coaxially aligned within the sleeve; a first ring in magnetic communication with the sleeve, coaxially aligned and configured to rotate relative to the sleeve. The first ring including a first plurality of axially directed teeth arranged about a circumference of the ring on a front portion thereof. The sensor also includes a second ring in magnetic communication with the first ring and the sleeve, the second ring coaxially aligned and configured to rotate relative to the first ring and the sleeve and including a second plurality of axially directed teeth configured substantially the same as the first plurality of axially directed teeth and oriented adjacent to the first plurality of axially directed teeth on a rear portion of the second ring. The coil generates a signal responsive to a differential displacement between the first and second rings.

Abstract: A method of detecting a sensed parameter for a motor control system comprising: receiving a sensor signal, the sensor signal exhibiting a frequency responsive to an inductance of a non-contacting variable reluctance rotational displacement sensor, wherein the inductance is indicative of a displacement of the sensor and responsive to the sensed parameter; capturing a first transition of the sensor signal and a time associated therewith; capturing a second transition of the sensor signal and a time associated therewith; calculating a period for the sensor signal; and computing a value for the sensed parameter, the value responsive to the period.

Abstract: An apparatus measures relative displacement between a first end and a second end of a shaft. The first and second ends being centered on a shaft axis. The apparatus includes first and second ferromagnetic plates. The first ferromagnetic plate has a first side and a second side and is connected to the first end. The first ferromagnetic plate is centered on the shaft axis and has a plurality of ferromagnetic teeth extending from the first side and in a first direction parallel to the shaft. The second ferromagnetic plate has a first side and a second side and is connected to the second end. The second ferromagnetic plate is centered on the shaft axis. The first and second ferromagnetic plates form a gap. The apparatus further includes a plurality of magnets having a magnetic field and a sensing device. The magnets are coupled to the first side of the second ferromagnetic plate. The sensing device is disposed within the gap for sensing a magnetic flux of the magnetic field.

Abstract: An apparatus for measuring relative displacement between a first shaft and a second shaft includes first and second rotor assemblies. The first rotor assembly is coupled to the first shaft and is centered on an axis. The second rotor assembly is coupled to the second shaft. The second rotor assembly has first and second stator plates. Each of the first and second stator plates includes an upper surface and a lower surface. The upper and lower surfaces are parallel. The first and second stator plates include a plurality of teeth extending in a direction radial of the axis. The first and second stator plates form a gap between the lower surface of the first stator plate and the upper surface of the second stator plate. The apparatus further includes at least one magnet having a magnetic field and disposed on the first rotor assembly and a sensing device disposed within the gap for sensing a magnetic flux of the magnetic field.

Abstract: A system and methodology for control of a switched reluctance electric machine comprising: a switched reluctance electric machine including a sensor generating and transmitting a sensor signal indicative of an operating characteristic; a controller operatively coupled to the switched reluctance motor and the sensor; and the controller executing a method.

Abstract: Disclosed herein is a method for parameter identification in a switched reluctance electric machine comprising: operating the switched reluctance electric machine in response to a desired command; and measuring an actual operating characteristic of the switched reluctance electric machine. The method also includes: modeling the switched reluctance electric machine to formulate an estimated operating characteristic based on the desired command; comparing the actual operating characteristic and the estimated operating characteristic to formulate an error there between; and determining a parameter estimate for the switched reluctance machine based on the error and a previous parameter estimate.

Abstract: A system and methodology for control of a switched reluctance electric machine comprising: a switched reluctance electric machine including a sensor generating and transmitting a sensor signal indicative of an operating characteristic; a controller operatively coupled to the switched reluctance motor and the sensor; and the controller executing a method.

Abstract: A motor for reducing torque ripple includes a shaft having a shaft axis, a rotor positioned about the shaft, a first magnet ring positioned on the rotor, the first magnet ring having magnets each occupying a magnet angle &dgr; on the rotor, and a second magnet ring positioned on the rotor, the second magnet ring having magnets each occupying a magnet angle &dgr; on the rotor, wherein the second magnet ring is shifted a non-zero number of degrees relative to the first magnet ring and wherein ends of each magnet within the second magnet ring are located at different angular positions than ends of each magnet within the first magnet ring relative to the shaft axis of the shaft. The magnet angle &dgr; is preferably an optimal magnet angle for minimizing cogging torque and line to line back emf harmonics.

Abstract: A motor for reducing torque ripple includes a shaft having a shaft axis, a rotor positioned about the shaft, a first magnet ring positioned on the rotor, the first magnet ring having magnets each occupying a magnet angle &egr; on the rotor, and a second magnet ring positioned on the rotor, the second magnet ring having magnets each occupying a magnet angle &egr; on the rotor, wherein the second magnet ring is shifted a non-zero number of degrees relative to the first magnet ring and wherein ends of each magnet within the second magnet ring are located at different angular positions than ends of each magnet within the first magnet ring relative to the shaft axis of the shaft. The magnet angle &egr; is preferably an optimal magnet angle for minimizing cogging torque and line to line back emf harmonics.

Abstract: Disclosed herein is a variable reluctance rotational displacement sensor comprising: an annular sleeve; a coil coaxially aligned within the sleeve; a first ring in magnetic communication with the sleeve, coaxially aligned and configured to rotate relative to the sleeve. The first ring including a first plurality of axially directed teeth arranged substantially equidistant about a circumference of the ring on a front portion thereof. The sensor also includes a second ring in magnetic communication with the first ring and the sleeve, the second ring coaxially aligned and configured to rotate relative to the first ring and the sleeve and including a second plurality of axially directed teeth configured substantially the same as the first plurality of axially directed teeth and oriented adjacent to the first plurality of axially directed teeth on a rear portion of the second ring. The coil generates a signal responsive to a differential rotational displacement between the first ring and the second ring.

Abstract: A method of detecting a sensed parameter for a motor control system comprising: receiving a sensor signal, the sensor signal exhibiting a frequency responsive to an inductance of a non-contacting variable reluctance rotational displacement sensor, wherein the inductance is indicative of a displacement of the sensor and responsive to the sensed parameter; capturing a first transition of the sensor signal and a time associated therewith; capturing a second transition of the sensor signal and a time associated therewith; calculating a period for the sensor signal; and computing a value for the sensed parameter, the value responsive to the period.

Abstract: A fault tolerant electric motor for steering actuation is disclosed. In an exemplary embodiment, the motor includes a stator assembly having a first group of stator windings and a second group of stator windings, thereby forming a redundant pair of stator windings. The first and second groups of stator windings are located within opposite hemispheres of the stator assembly. A rotor assembly is rotatingly disposed within the stator assembly, and has a plurality of magnets disposed around the periphery of a rotor core. Each of the plurality of magnets is arranged into a pair of segments, one of which is shifted from the other with respect to an axis of rotation of the rotor assembly.