Abstract: A motor driving circuit coupled to a motor having a plurality of phases of coils includes a standard power source generating a first power supply voltage, and a step-up power source for generating a second power supply voltage greater than the first power supply voltage. A selecting circuit selects either the first power supply voltage or the second power supply voltage in response to a selecting signal. A motor driving circuit causes currents to flow in the phases of the motor in accordance with motor driving signals respectively related to the phases in a state in which a selected power supply voltage output by the selecting circuit is applied to one or more phases. A switching unit generates the selecting signal on the basis of the motor driving signals and a voltage signal corresponding to a current flowing through at least one of the phases of the motor so that the second power supply voltage is selected first and the first power supply voltage is selected second with respect to each of the phases.

Abstract: The present invention employs digital circuitry to compensate for variations in DC link voltage transmitted to a switched reluctance machine. The digital voltage compensation system of the present invention periodically samples the DC link voltage and actual rotor speed, then supplies the samples in digital form to a microcontroller that derives a compensated speed signal to compensate for changes in DC link voltage.

Abstract: A computer having a hard disk drive includes a battery voltage monitor which establishes a shut down condition of the computer if the supply voltage falls below a chosen level V.sub.L. Upon start up of the hard disk drive motor, current through the motor is limited so that supply voltage of the battery to a computer does not fall below level V.sub.1, which level is greater than the level V.sub.L. Additionally during start up, current in the motor is controlled so that voltage supplied by the battery to the computer does not rise above a threshold level V.sub.2 which is greater than V.sub.1.

Abstract: Here is disclosed an IC for controlling the spindle motor of a small hard disk drive unit, characteristic in being provided with a voltage detection circuit for a control circuit driving power source, responsive to the voltage at the connecting terminal of the control circuit driving power source for generating a signal to control the operation of the spindle motor; a voltage detection circuit for a motor driving power source, responsive to the voltage at the connecting terminal of the motor driving power source for controlling the operation of the motor; and further provided with a logic circuit for keeping valid the output signal of the voltage detecting circuit for said motor driving power source from the time the voltage at the motor driving power source terminal rises above a prescribed voltage higher than the upper limit of the prescribed voltage range of the control circuit power source until the time it falls below another prescribed voltage lower than the lower limit of said prescribed voltage range.

Abstract: A compact surgical handpiece comprises a motor energizable for moving a tool member, electric energy supply actuable for energizing the motor and a manually actuable trigger actuable to control motor operation. A motor control circuit interconnects the motor electric energy supply and trigger for running and braking the motor in response to actuation and release of the trigger. The control circuit includes a compact regulated voltage supply, a motor overcurrent limiting feature and a motor braking feature which is effective even if the operator fails to fully disconnect the electrical supply to the motor upon releasing the trigger.

Abstract: A current regulator phase controls a power signal to control silicon controlled rectifiers arranged in a bridge. The silicon controlled rectifiers excite a generator field of an elevator drive. Discontinuity in the generator field current, caused by the inductive load and latching and holding currents in the silicon controlled rectifiers, is detected to provide an analog discontinuity signal. The analog discontinuity signal is converted to digital form and used to dynamically alter the gain and response of the regulator.

Abstract: The method consists in mounting the armature of an motor in a bridge circuit and in injecting, at the input of a circuit for amplifying the supply of the bridge receiving the control voltage, an automatic control signal corresponding to the difference between the intensity feedback and the voltage feedback picked up at the terminals of the bridge. Upstream of the amplifier circuit, there is injected an AC voltage with a frequency greater than a cut-off frequency of the motor, the AC voltage generating an AC component of the above-mentioned automatic control signal representing a disequillibrium of the bridge due to a variation of the armature resistance. This AC component is used as a source of a control signal of the gain of an amplifier with adjustable gain of an intensity feedback present at one of the terminals of the bridge.

Abstract: A steering control apparatus for a motor vehicle with steerable front and rear road wheels keeps electric power supplied to an electric motor for turning the rear road wheels, at a desired value even when the voltage of a vehicle-mounted battery for energizing the motor fluctuates. The steering control apparatus includes a battery mounted on the motor vehicle, an electric motor energizable by electric power supplied from the battery for applying power output to at least a steering mechanism for turning the rear road wheels, detecting means for detecting the voltage of the battery, and a motor control unit for controlling operation of the electric motor.

Abstract: A method and apparatus for operating a DC motor controller according to a first gain when the armature current of the DC motor is discontinuous, according to a second gain when the armature current is continuous, and according to a third gain when the armature current is in transition from the discontinuous to continuous conduction. The gains have proportional and integral terms and the integral term in the discontinuous and transition regions varies inversely to a current reference in the controller.

Abstract: A method for operating a DC motor controller according to a first gain when the armature current of the DC motor is discontinuous, according to a second gain when the armature current is continuous, and according to a third gain when the armature current is in transition from the discontinuous to continuous conduction. The gains have proportional and integral terms and the integral term in the discontinuous and transition regions varies inversely to a current reference in the controller.