Abstract: A magnetostrictive force sensor universally usable in any environment with similar signals unaffected by the surrounding material. To this end, a sensor comprising a shaft of magnetostrictive material with an inductance coil wound around the shaft is provided with a magnetic shell enclosing the coil only or both the coil and the shaft. Upon application of the magnetic field, the resultant flow of magnetic flux is confined to a path through the shaft and the magnetic shell. By confining the magnetic flux path, the dependency of the sensor signal on the surrounding material and environment is essentially eliminated.

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: An apparatus for controlling the load dump voltage of a permanent magnet (PM) alternator having a silicon controlled rectifier (SCR) bridge. The apparatus includes a voltage divider, a peak detector, and a comparator. The voltage divider attenuates the bridge output voltage, which is further fed through a peak detector to hold the peak value for improved stability. The comparator changes states when the bridge output exceeds a predetermined voltage level (e.g., 55 volts) that is less than the load dump threshold limit (e.g., 60 volts), but greater than the normal operating voltage (e.g., 42 volts). The comparator output change-in-state deactivates a gate pulse generator, thereby suppressing further operation of the SCR bridge. Voltage transients that may otherwise occur at the bridge output for the remainder portion of a half cycle from the PM alternator are clamped using a varistor or zener diode.

Abstract: A three region control strategy for a permanent magnet motor is presented. In a first control region, the permanent magnet motor is operated at, a 120° conduction square wave mode at reduced phase current, and below a no-load speed. The motor phase current commutation causes eddy current losses in the rotor magnets and core which are insignificant due to the low phase currents and relatively low rotor speed. Meanwhile, the inverter switching losses are kept low as two switches are in use (on/off) for each current commutation during the 120° conduction mode. In a second control region, the permanent magnet motor is operated at a 180° conduction sinusoidal wave mode with high phase currents. The 180° conduction sinusoidal wave mode minimizes the commutation loss. In a third control region, the permanent magnet motor is operated above its no-load speed or in a field weakening mode.

Abstract: An exemplary embodiment of the invention is a method for torque control of a PM synchronous machine. The method includes obtaining a torque command signal and a machine speed and determining an operating mode in response to the torque command signal and the machine speed. The operating mode includes a first operating mode and a second operating mode. In the first operating mode, a stator phase voltage magnitude is computed and an angle between the stator phase voltage and a stator phase back emf is determined in response to the stator phase voltage magnitude. In the second operating mode, the stator phase voltage is set to a predetermined magnitude and the angle between the stator phase voltage and the stator phase back emf is determined in response to the predetermined magnitude.

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: An analog angle encoder includes a non-magnetic stator which is cup-shaped, having a central post carrying at least one magnetosensitive device, and further including a rotor in the form of a ring captured by the stator, the rotor carrying at least one permanent magnet, wherein the rotor is rotatable relative to the stator. As the rotor rotates relative to the stator, the angle of the incident magnetic field changes relative to the magnetosensitive device, thereby causing the output from the device to vary sinusoidally with angular position. It is preferred to use magnetic configurations other than simple six sided magnets in order to achieve a more uniform magnetic field at the magnetosensitive device, as for example by utilizing cylindrical magnets, arcuate (concave faced) magnets, flat ferromagnetic layer pole pieces, arcuate (concave faced) ferromagnetic layer pole pieces, and ferromagnetic return paths.

Abstract: An apparatus for controlling the load dump voltage of a permanent magnet (PM) alternator having a silicon controlled rectifier (SCR) bridge. The apparatus includes a voltage divider, a peak detector, and a comparator. The voltage divider attenuates the bridge output voltage, which is further fed through a peak detector to hold the peak value for improved stability. The comparator changes states when the bridge output exceeds a predetermined voltage level (e.g., 55 volts) that is less than the load dump threshold limit (e.g., 60 volts), but greater than the normal operating voltage (e.g., 42 volts). The comparator output change-in-state deactivates a gate pulse generator, thereby suppressing further operation of the SCR bridge. Voltage transients that may otherwise occur at the bridge output for the remainder portion of a half cycle from the PM alternator are clamped using a varistor or zener diode.

Abstract: An electric vehicle accessory motor drive power supply system (40) that utilizes a single power supply design to provide efficient variable speed motor control to both brushless and brush-type DC motors (42,44). The power supply system includes at least one of each type of motor along with a first DC-DC converter (46) that provides operating power to the brushless motor (42) and a second DC-DC converter (48) that provides operating power to the brush-type motor (44). Both converters (46,48) have a power input (52) connected to the electric vehicle's high voltage bus (50) and each includes a data input (54) for receiving a speed control signal (SC) indicative of desired motor speed, as well as an output (56) for providing a motor drive signal to its associated DC motor (42,44).

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 housing for a wireless emergency safety light which is mechanically connectable to a conventional light switch for a light fixture or a plug receptacle for providing power to a load. The housing replaces a conventional switch plate having at least one opening for receiving the switch actuator of the light switch or for receiving the electrical plug receptacle. The emergency safety light includes at least one compartment in the housing for receiving batteries; a second compartment in the housing for receiving an emergency light source adapted to be connected to the batteries; and an antenna for sensing the loss of electrical power to the light switch and, in response thereto, for actuating the emergency light source.

Abstract: A valve assembly is disclosed for metering exhaust gas to the intake manifold of an internal combustion engine. The valve assembly has a base which includes a passage communicating between the intake manifold and the exhaust manifold of the engine. The passage has a valve seat which is operable with a valve member to meter the flow of exhaust gas through the passage to the intake manifold. An actuator assembly is mounted to the base and is operably connected to the valve member to move the valve member into and out of engagement with the valve seat. The actuator assembly includes a solenoid having a magnetic circuit comprising stationary primary and secondary pole pieces and a moveable armature.