Abstract: A method and device for controlling an electric motor, in particular a machine tool drive, wherein during a sensorless open-loop control mode of operation of the electric motor the speed and the torque are determined from the motor current and the motor voltage, and the moment of inertia of the electric motor torque are determined from the determined motor current and the determined motor voltage, wherefrom then a control torque is determined, which is then associated with an open-loop torque control value and supplied as the torque setpoint value to a control element for setting the motor current and/or the motor voltage in the open-loop mode of operation. As long as the speed is below a minimum speed, the control element receives as input variable a control or pilot control torque generated from a predefined moment of inertia for a sensorless closed-loop control mode of operation of the electric motor.

Abstract: A brushless motor driven by a sensorless driving circuit includes a rotating body capable of being rotated about a center axis; a rotor magnet arranged coaxially with the rotating body; a stator disposed opposite the rotor magnet; and at least one coil wound around the stator. The brushless motor is driven according to a signal containing a third harmonic component relative to a fundamental wave component in an induced electromotive force. Further, an amplitude ratio of the third harmonic component to the fundamental wave component in the induced electromotive force generated in the coil preferably is about 1% or higher.

Abstract: A control device for driving a motor which includes a rotor and a stator is provided. The control device includes a Hall detector and driving circuit. The Hall detector detects magnetic flux variation when the rotor rotates and generates a first detection signal and a second detection signal. The first and second detection signals represent current rotation location when the rotor rotates. The driving circuit generates a driving signal to drive the stator. The driving circuit turns on or off the driving signal according to a control signal and the relationship between the first and second detection signals.

Abstract: A feed motor lock detection device detects a back-electromotive voltage in a feed motor M and checks whether the feed motor M is in a driven state or in a non-driven state based on the level of the back-electromotive voltage.

Abstract: An electric motor controller for a vehicle has a voltage detecting section for detecting the voltage of a filter capacitor inserted on a direct current side of an inverter device including a semiconductor element for large electric power; an electric current detecting section for detecting an output electric current of the inverter device; and a temperature detecting section arranged in a cooling means of the semiconductor element for large electric power. Loss generated by a switching operation of the semiconductor element for large electric power is sequentially calculated by outputs of the detecting sections. Excessive temperature is detected when junction temperature of the large electric power semiconductor element calculated by this loss reaches an allowable temperature.

Abstract: Presented in an apparatus for controlling a brushless DC motor with a permanent magnet arranged on a rotor and a stator with windings. The apparatus includes an observer that is adapted to determine an estimated temperature of the permanent magnet as a function of the temperature of the windings, and determine at least one actuating signal for controlling the DC motor as a function of the estimated temperature of the permanent magnet.

Abstract: The present invention is a driving circuit for a DC brushless fan motor, comprising a control unit, a motor, a Hall element, a signal output unit, a temperature control circuit, a reverse protection circuit and a counter-electromotive force (CEMF) removal circuit, as tied in with a plurality of resistors, capacitors, diodes and transistors. Accordingly, the ambient temperature is sensed by the temperature control circuit and is fed back to control the rotation rate of the motor.

Abstract: Methods and apparatus permit: monitoring a level of a power source that provides operating power to a control circuit, the control circuit being of a type that senses signals in windings of a polyphase motor to maintain synchronization therewith; and converting kinetic energy of the polyphase motor into operating power for the control circuit when the level has fallen below a threshold level, such that the control circuit is capable of maintaining synchronization with the polyphase motor.

Abstract: A device for position determination in a sensorless direct current motor has a plurality of inductivities arranged in corresponding phases and inducing alternating voltages in a motor windings, a plurality of resistances located in phase branches to be evaluated for a position determination of a rotor position of the sensorless direct current motor, and a plurality of comparator components each associated with the corresponding phase branch to be evaluated.

Abstract: The invention concerns a motor controller for a motor with a feedback potentiometer, preferably for central air valve actuation. In the field of climate control, for example for utility vehicles and motor vehicles, the air ducts in heating, air conditioning and/or ventilation systems have valves to control the flow of air or water. These valves are adjusted either mechanically, e.g. by Bowden cables or flexible shafts, or using motors. It is proposed that a continuous rotation potentiometer be employed as a feedback potentiometer and specially designed control electronics be used to control a motor with the continuous rotation potentiometer. In the control electronics for the motor controller, an angular difference between an adjusted control potentiometer and the motor feedback potentiometer is determined in order to determine therefrom the shortest adjustment path to the chosen setpoint position for the motor when the angular difference is greater than 180 degrees.

Abstract: A local oscillator and logic circuit pulses the open winding of a brushless DC motor at start up and the back EMF is used to generate a voltage to boost the voltage available to the control circuit for optimizing performance when starting with low supply voltage. As the rotor of a motor rotates and the windings are commutated by the drive electronics there is generated in each winding a voltage caused by the collapse of the current and the inherent inductance of the winding. These voltages exceed the normal operating voltage of the motor. The energy in these voltages is used to generate a regulated power feed to the analogue circuitry of the control circuit at a suitable voltage level. During steady state conditions, when the motor is running, the commutation of the windings is continual and there is ample energy available to power analogue electronics, and, if required, associated digital electronics as well.

Abstract: A device for controlling a motor intended to set an arm provided with a head for reading/writing information in motion with respect to a surface carrying information. The device having a controller for enabling the power supply of the winding of the motor to be managed and a measurer for measuring the value of a counter-electromotive force induced in the winding by the movement of the rotor when the power supply of the winding is interrupted. This device enables the angular speed of the arm to be measured and controlled during an emergency return phase of the arm towards a rest position.

Abstract: A motor drive circuit for driving a brushless motor having a rotor and exciting coils of respective phases. A square wave rotor position signal for each phase is produced wherein a half period of the rotor position signal corresponds to a time period from a polarity inversion of an induced voltage of the exciting coil to the next polarity inversion of the induced voltage. Based on the rotor position signal, excitation of the exciting coils is performed by controlling switching elements for conducting excitation currents by using square wave on-control and/or pulse width converted square wave pulse width modulation (PWM) control. A pulse width converted sinusoidal wave PWM signal is generated whose pulse width varies according to a sinusoidal function. Excitation of the exciting coils is controlled based on the pulse width converted sinusoidal wave PWM signal immediately before and after the square wave on-controlled portions and/or the pulse width converted square wave PWM controlled portions.

Abstract: A measurement device has a laser light source for irradiating a laser light, a reflecting mirror for reflecting the laser light irradiated from the laser light source in a preselected direction and/or for scanning the laser light within a preselected angle range, and an oscillating motor for driving the reflecting mirror to reflect the laser light in the preselected direction and/or oscillating the reflecting mirror within the preselected angle range to scan the laser light. The oscillating motor has a main shaft for undergoing rotational oscillating movement and for supporting the reflecting mirror for rotational oscillating therewith, a connecting device for removably connecting the reflecting mirror to the main shaft, and a detecting device for detecting a rotation angle of the main shaft. A reflector reflects the laser light reflected and/or scanned by the reflecting mirror. A light receiving element receives the laser light reflected by the reflector.

Abstract: A rotary body drive device for controlling rotation of a motor on the basis of the phase difference between a periodic signal produced in accompaniment with rotation of the motor and a reference clock signal so that their phase relationship becomes a prescribed one. When the phase difference between both signals detected in a certain state is largely different from that detected in the preceding time, a correction is given to the phase difference of both signals detected in the aforesaid certain state, so that the rotation of said motor is controlled in accordance with the corrected phase difference.