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 method for determining phase current for each of a plurality of individual phase coils of a switched reluctance machine (SRM) is disclosed. In an exemplary embodiment, the method includes determining the current passing through a first resistive element and a second resistive element in an SRM drive circuit. A conduction mode of the SRM drive circuit is determined, the conduction mode being based upon an ON/OFF state of each of a pair of switching transistors controlling current through each of the plurality of individual phase coils. The phase current through each of the plurality of individual phase coils is then calculated, based upon the conduction mode and the determined current passing through said first and second resistive elements.

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: An integrated control device for an environmental system comprises a motor that is in mechanical communication with a device forcing fluid through the environmental system and a controller physically mounted to the motor. The controller includes a processor programmed to control the motor and at least one other internal system of said environmental system in response to a thermostat control signal. The other internal system may comprise a heater and/or cooling unit.

Abstract: A brushless electric motor is disclosed. In an exemplary embodiment of the invention, the motor includes a permanent magnet rotor having a plurality of magnetic poles thereupon and a stator. The stator further includes a plurality of stacked laminations defining a plurality of slots therein, and a plurality of fractional-pitch phase windings disposed within the plurality of slots. The motor has a non-integer slots-per-pole ratio, and a magnitude of 5th and 7th harmonic components of a fundamental frequency component of the motor are less than 0.3% and 0.1% of a magnitude of the fundamental frequency component, respectively.

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 method for determining phase current for each of a plurality of individual phase coils of a switched reluctance machine (SRM) is disclosed. In an exemplary embodiment, the method includes determining the current passing through a first resistive element and a second resistive element in an SRM drive circuit. A conduction mode of the SRM drive circuit is determined, the conduction mode being based upon an ON/OFF state of each of a pair of switching transistors controlling current through each of the plurality of individual phase coils. The phase current through each of the plurality of individual phase coils is then calculated, based upon the conduction mode and the determined current passing through said first and second resistive elements.

Abstract: A permanent magnet structure for use in brushless motors is disclosed. In an exemplary embodiment of the invention, the magnet structure includes a parallelogram shaped body. The body has an outer surface and an inner surface, with the outer surface and the inner surface being arcuate in shape.

Abstract: A method for compensating for dead time non-linearities in a pulse width modulation (PWM) controlled device including obtaining a motor data signal, generating a duty cycle of the motor voltage responsive to the motor data signal, determining a compensation value responsive to the duty cycle of the motor voltage, generating a compensated duty cycle in response to the compensation value and the duty cycle of the motor voltage and introducing the compensated duty cycle to the PWM controlled device. In addition, a medium encoded with a machine-readable computer program code for compensating for dead time non-linearities in a pulse width modulation (PWM) controlled device, the medium including instructions for causing controller to implement the aforementioned method.

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.

Abstract: A method for compensating for dead time non-linearities in a pulse width modulation (PWM) controlled device including obtaining a motor data signal, generating a duty cycle of the motor voltage responsive to the motor data signal, determining a compensation value responsive to the duty cycle of the motor voltage, generating a compensated duty cycle in response to the compensation value and the duty cycle of the motor voltage and introducing the compensated duty cycle to the PWM controlled device. In addition, a medium encoded with a machine-readable computer program code for compensating for dead time non-linearities in a pulse width modulation (PWM) controlled device, the medium including instructions for causing controller to implement the aforementioned method.

Abstract: A circuit for disconnecting a neutral point of an electric machine includes an inductance connected to a lead of the electric machine; a three-terminal solid-state switch that has a first terminal connected to the inductance, a second terminal connected to the neutral point, and a third terminal for controlling a flow of current between the first and second terminals; a controlling circuit coupled to the three-terminal solid-state switch that includes a first loop that has a power source, a resistance, and a voltage regulator to maintain a first voltage upon the third terminal, and a second loop that has a power source, a resistance, and a trigger switch being controllably switched on to thereby close the first loop whereby a second voltage is applied to the three-terminal solid-state switch to thereby substantially electrically disconnect the first terminal from the second terminal.

Abstract: A permanent magnet structure for use in brushless motors is disclosed. In an exemplary embodiment of the invention, the magnet structure includes a parallelogram shaped body. The body has an outer surface and an inner surface, with the outer surface and the inner surface being arcuate in shape.

Abstract: A brushless electric motor is disclosed. In an exemplary embodiment of the invention, the motor includes a permanent magnet rotor having a plurality of magnetic poles thereupon and a stator. The stator further includes a plurality of stacked laminations defining a plurality of slots therein, and a plurality of fractional-pitch phase windings disposed within the plurality of slots. The motor has a non-integer slots-per-pole ratio, and a magnitude of 5th and 7th harmonic components of a fundamental frequency component of the motor are less than 0.3% and 0.1% of a magnitude of the fundamental frequency component, respectively.

Abstract: A rotor assembly for a brushless motor is disclosed. In an exemplary embodiment of the invention, the rotor assembly includes a core having a central opening for insertion of a rotor shaft therein. A plurality of rotor magnets disposed upon a periphery of the core, wherein a space is defined between one of the plurality of rotor magnets and another of the plurality of rotor magnets. A portion of said core occupies said space, thereby defining a salient pole therewithin.