Abstract: A control system for a multiphase permanent magnet motor having a controller for producing a control signal to energize each phase winding. The controller includes a current value calculator for determining a value of phase current advanced in phase with respect to back-EMF by a phase advance angle, and a phase advance optimization circuit for producing a value of the phase advance angle optimized so as to maximize output torque of the motor and mimimize the phase current. The phase advance optimization circuit determines the phase advance angle optimized for each phase of the motor.

Abstract: A method for controlling a mechanically commutated electric motor, wherein the rotational angle of the output of said motor is determined by means of detection of the change in back electromotive force, when the electric motor commutates, and wherein the power supply to the electric motor is halted after a predetermined number of detected commutations.

Abstract: An aperture driving apparatus includes a swing unit and a stationary unit. The swing unit includes an aperture plate that partially blocks a light, a coil that constitute a voice coil motor for obtaining a driving force for driving the aperture driving plate, and a swing arm that supports the aperture plate and the coil and has a bearing portion between the aperture plate and the coil. The stationary unit includes a swing shaft that engages the bearing portion and swingably supports the swing arm about a swing axis, and a magnet and a yoke that constitute the voice coil motor together with the coil. A control unit of the aperture driving apparatus controls the swing angle of the swing arm using a closed-loop control technique. In the direction of the swing axis, the position of a center of gravity of the swing unit is substantially aligned with a position at which the driving force is applied to the coil.

Abstract: A circuit for driving an appliance for treating laundry, includes a motor circuit having an AC motor, and a door-locking circuit. The motor circuit and the door-locking circuit may be driven by a single common electronic switching element.

Abstract: A DC motor phase estimation algorithm that estimates a speed-related harmonic frequency of a DC motor current under dynamic load conditions having known geometry parameters. The algorithm estimates the phase and magnitude of a complex coefficient in a complex single frequency adaptive filter that receives a primary signal from the motor current and estimates a reference signal using an incident frequency by adapting the complex coefficient to match the magnitude and phase of the speed-related harmonic component of the primary signal. The rate of change of the phase of the complex coefficient is determined by a phase-lock loop coupled to the adaptive filter to adapt a dynamic incident frequency corresponding to a single frequency component of interest in the primary signal. The incident frequency is extracted, and the motor speed is estimated using the extracted incident frequency and the known motor geometry parameters.

Abstract: A method of determining a rotational state of a three-phase alternating voltage supply which is connected to a converter and rotating in an uncontrolled manner, wherein the converter is connected to an intermediate voltage circuit and comprises phase-specific upper and lower controllable switches, which are connected in series between the intermediate voltage circuit, free-wheeling diodes connected in parallel with each of the controllable switches, and resistive circuits connected in parallel with the lower controllable switches.

Abstract: It is an object of the invention to provide a motor control apparatus capable of ensuring a control function even for a large inertia moment ratio.

Abstract: The invention relates to a method for power control of an electric motor, in particular a motor for driving the suction fan of a vacuum cleaner connected to an AC mains power supply. The power control is effected by varying the phase angle of the electric alternating quantity supplied to the motor by the use of semiconductor switches. AC power supplied to the motor is switched by using different delay times for the switching in each half-period of a full AC period to suppress odd harmonics, particularly the third harmonic of the mains power line frequency. Half-periods of a full period are mirrored in the next consecutive full period in order to suppress even harmonics, particularly the second harmonic of the mains power line frequency. A set of delay times t1 and t2 are defined and selected to be used in further avoiding critical delay time areas for harmonics and minimize the generation of vibrations.

Abstract: The controller for a brushless motor controls motor current by executing updates of applied voltage to a coil in accordance with rotational position of a rotor, the target current, and the actual current flowing through the coil. The updates of applied voltage to the coil are executed according to the results of calculations of applied voltage to the coil in accordance with the rotational position of the rotor, the target current, and the actual current flowing through the coil, in order to generate power for rotating the rotor by varying magnetic field generated by the coil. The cycle time of the updates of applied voltage is shorter than the cycle time of the calculations of applied voltage corresponding to the rotational position of the rotor.

Abstract: In rotating systems with angular references, angular- and/or time-based pulses must be generated which can be described in a generic manner to meet various requirements. The parameters for definition of the pulse are assigned as a value pair to permit more flexibility on definition of a pulse for generation, one value of which defines the type of the parameter, in other words, whether an angle, a time, or some other parameter is being defined. A calculation device can correctly assign the size value of the parameter using the additional value, interpret and carry out suitable subroutines to calculate the control values for controlling the relevant pulse generation circuits.

Abstract: A method and apparatus for controlling the speed of a DC electric motor receives a periodic commutation signal having a fixed duration on cycle and an off cycle. The commutation signal then is modified to form a periodic modified commutation signal having substantially the same period duration as the commutation signal. The modified commutation signal has a single on cycle per period. The method and apparatus then determine a desired speed of the motor, and vary the duration of the on cycle of the commutation signal to form the on cycle of the modified commutation signal. The on cycle of the modified commutation signal has a duration that is less than the fixed duration. By varying in this manner, the rotor rotates at substantially the desired speed.

Abstract: In an automatic transmission position control by a motor, it is determined whether the present instant belongs to a starting period, that is, the present instant is immediately after resetting of a control unit or application of power to it. If it is the starting period, an actual shift position that is detected from an output of an output shaft sensor for detecting a rotation position of a motor is set as an instructed shift position. With this measure, even if the control unit is reset for a certain reason while the vehicle is running, the instructed shift position is not changed in association with the resetting. This prevents trouble that the shift position is switched contrary to the intention of the driver, whereby the reliability of a position switching control can be increased.

Abstract: A synchronous control device which is provided with drive motors and a central control unit generating a synchronous reference signal and with which the drive motor is controlled to rotate synchronously with the synchronous reference signal supplied from the central control unit, which is provided with: device motor brakes for braking a rotation of the drive motor; machine home position detectors for detecting a rotation phase of the drive motor; and drive controlling means for controlling a drive motor in such a manner that the drive braking means is activated depending on a stop instruction supplied from the central control unit and a required rotation phase of the drive motor is stored; a comparison between the required rotation phase of the drive motor and the rotation phase thereof is performed at the time of re-start; and a home position alignment of the drive motor is performed at a start time of a subsequent operation.

Abstract: A method for reducing EMI emissions in the control of an electric motor supplied by a switching inverter fed by a DC bus comprising controlling a phase advance of a conduction angle period during which a phase of the motor is fed power by the inverter to control the conduction angle to control the speed of the motor, thereby to reduce the number of switching operations of the inverter and thereby reduce EMI.

Abstract: A novel system for adaptively controlling an electric vehicle to maintain desired speed under variable driving conditions. The system includes a control circuit for producing a control signal to control an electric motor of the vehicle. The control signal is formed based on a control current required to achieve the desired speed. The control strategy selection circuit is configured in the system to determine a motor control scheme that provides an appropriate waveform profile of the control current.

Abstract: A method for implementing control signal linearization for an electric motor is disclosed. In an exemplary embodiment, the method includes receiving a desired voltage command to be applied to the motor and determining whether the magnitude of the desired voltage command falls between a first value and a second value. If the magnitude of the desired voltage command falls between the first value and the second value, then modulating a voltage command between the first and the second value over a determined sample period, thereby resulting in the application of a modulated voltage command to the motor.

Abstract: An electric motor circuit utilized, for instance, for adjusting a wing mirror of a vehicle is provided with a motor with a driving circuit. The driving circuit includes a relay switch element included in series with the motor and a protecting circuit for bringing the relay switch element into a non-conductive position at overload of the motor. The protective circuit is provided with an exciting coil and a deenergizing coil. The exciting coil serves for bringing the relay switch element into a conductive position. The exciting coil is included parallel to the motor in series with the relay switch element. The deenergizing coil is included in series with the motor for bringing the relay switch element in a non-conductive position when a current through the deenergizing coil and the motor exceeds a threshold value. Motor and motor protection are preferably included together in the housing of a mirror construction.

Abstract: An objective is to provide a specific realization means for easily determining malfunction of a system in an electromotive power steering controller. The electromotive power steering controller includes: a voltage controller for controlling voltage applying to a motor based on a d-axis current command value and a q-axis current command value that are set by a d-q-command-value setting unit, and a d-axis current detection value and a q-axis current detection value that are obtained by, using the d-q coordinate system, transforming three-phase ac current that has been actually flowing in the motor and has been detected by a current detector; and a malfunction determining unit for determining that malfunction has occurred in the control system if at least one of the phase-current detection value is out of a first predetermined permissible range.

Abstract: In an AC or DC motor operation and power generation system, a periodic transformation system reduces or prevents harmonic distortion, reduces resistance or impedance, and improves energy efficiency in a signal either consumed, such as in a motor, or produced, such as in a generator. In one embodiment, the TruScale Reactance Transformation System or the Eastern Modified TruScale Octave Transformation System are the periodic transform systems provided to prevent overtone collisions in current and voltage signals, in order to maximize energy spectral density, and to precondition either DC or AC signals.

Abstract: A method and an apparatus for adjustment of the rotor angle of an elevator motor (M), in which method: the rotor angle of the elevator motor is measured, the rotor angle is adjusted by using the measured rotor angle value as feedback data, and the rotor angle is measured by a pulse emitter (PE) or tachometer connected to the elevator motor. In the method, a disturbance signal (u) is fed into the rotor angle feedback data to produce a change (disturbance) in the rotor angle, the change (disturbance) is compared to the disturbance signal (u), and, on the basis of the comparison, a control signal is generated to adjust the rotor angle.

Abstract: An apparatus and method for controlling a linear compressor is provided. The linear compressor controlling apparatus includes a voltage detection unit, a current detection unit, a control unit and a compressor drive unit. The voltage detection unit detects a voltage supplied to the linear compressor, while the current detection unit detects a current supplied to the linear compressor. The control unit determines whether a collision of a piston of the compressor with a valve of the compressor occurs using output signals of the voltage and current detection units, and controls the amplitude of the piston if the collision of the piston with the valve occurs. The compressor drive unit controls the amplitude of the piston under the control of the control unit.

Abstract: An induction motor system comprising an induction motor, equipped with a heat recovery and water pumping apparatus and an apparatus for controlling the electrical efficiency and resulting heat generation of the induction motor. The motor is adapted to be coupled to an AC source for supplying an AC signal. The controlling apparatus includes a switching device, user controls and optional inputs. The switching device is connected in series with the motor and is operative in either a high impedance state wherein significant current flow through the motor is prevented or a low impedance state wherein current flow through the motor is substantially undisturbed. The user controls provide motor operational input signals. The optional inputs provide setpoint and sensed water temperature input signals.

Abstract: A controller for a brushless motor that suppresses torque reduction resulting from the influence of motor inductance and suppresses the generation of invalid current. A phase advancing angle calculator calculates a delay angle of phases of phase currents with respect to the phases of the phase voltage command and a phase advancing angle corresponding to the delay angle based on the function of the angular velocity and the motor inductance (and armature winding resistance) of the brushless motor. An adder adds the phase advancing angle to the rotation angle provided from the rotation angle calculator to generate the corrected rotation angle. The adder further provides the corrected rotation angle to a two-phase/three-phase converter.

Abstract: A motor control system according to the present invention comprises a magnetic encoder including a magnetic drum fixed to an output shaft of a motor and a magnetic sensor provided against a periphery of the magnetic drum through a space, an angle calculating unit for calculating a rotational angle of the motor from an output of the magnetic encoder, an angle estimating unit for estimating the rotational angle, an error angle calculating unit for finding an error angle from an calculated angle calculated by the angle calculating unit and an estimated angle estimated by the angle estimating unit, an error-correction value calculating unit for calculating from the error angle an error-correction value that corresponds to the rotational angle, a correction calculating unit for calculating a correction angle or a correction speed from the calculated angle and the error-correction value, and a motor operation controlling unit for outputting to an inverter a voltage command value that corresponds to the correction a

Abstract: A control system for a motor including a rotor comprises a sensorless sensor module that includes a saliency-based estimator module that generates a first rotor position signal based on saliency and a back electromotive force (emf) estimator module that generates a second rotor position signal based on back emf. A selector selects the first rotor position signal for rotor speeds below a first rotor speed and the second rotor position signal for rotor speeds above the first rotor speed. A rotor position sensor senses a position of the rotor and generates a third rotor position signal. A fault detection module senses faults in the rotor position sensor and outputs the third rotor position signal when a fault is not detected and one of the first and second rotor position signals when the fault is detected. An indirect field oriented control (IFOC) system controls the motor based on a selected one of the first, second and third rotor position signals.

Abstract: The invention relates to a device and a method for determining an electrical starting rotor angle of an electromotor. According to the invention, the electromotor (10) is subjected to an approximately sinusoidal voltage and the corresponding current path (i) that is established is then detected. The electromotor (10) is again subjected to an approximately sinusoidal voltage and again, the corresponding current path (i) is detected. A ratio of a measure of the fundamental wave (I1) and the measure of the first harmonic wave (I2) is then determined from the current paths (i) as a measure of the electrical starting rotor angle (?).

Abstract: A method with which the load current and thus the load moment of an asynchronous motor that is controlled via a phase-controlled two-phase thyristor power controller, can be easily influenced so as to allow a smooth starting operation. According to a first embodiment, the ignition point is determined in the controlled phase in order to adapt the flow angles of the subsequent current half waves. According to a second embodiment, the ignition point of the subsequent current half waves is brought forward in both controlled phases.

Abstract: In a DC motor driven by sinewave power-on driving and having hall elements shift-mounted relative to a stator for detecting the position of a rotor, a reduction in starting torque is eliminated by avoiding a braking action occurring when switching phases on starting the motor. In the case of the sinewave power-on driving, the braking action may occur owing to delay of the current flowing through the windings of the motor by the influence of an inductance value of stator windings and induced voltage of the motor. In order to avoid the braking action, hall elements for detecting the position of the rotor are shift-mounted. However, the braking action would be likely to occur on the contrary, because the induced voltage is low when the motor is started.

Abstract: A method for implementing active deadtime control of an inverter associated with an electric motor is disclosed. In an exemplary embodiment, the method includes receiving a command voltage signal indicative of a desired load to be driven by the motor. Based upon the value of the command voltage signal, a determined value of deadtime is applied to switching circuitry in the inverter, wherein the value of deadtime relates to an amount of time in which the switching of a device in the switching circuitry is delayed so as to prevent a short circuit condition within the inverter.

Abstract: In an electric motor apparatus of the present invention, both of energized spiral wires 17A and 17B for a first system 18A and a second system 18B cooperate to rotate the rotor 25 in a normal condition, however, when it is happened an abnormal condition in one of the first system and the second system, the energized spiral wires of the other system rotate the rotor 25 so that the present invention can prevent the rotation of the electric motor 14 from stopping just after the abnormal condition in either of the systems to achieve a fail-safe function. Therefore, the present invention can decrease a number of parts in comparison with the conventional apparatus having two actuators to restrain an increase of the cost and to achieve a compact structure.

Abstract: A novel cruise control system is provided for adaptively controlling an electric vehicle to maintain desired speed under variable driving conditions. This system utilizes multiple motor control scheme for controlling the motor using various waveform profiles of the control current, and involves phase advance angle adjustment provided for adaptively controlling a phase advance angle between the control current and back-EMF in response to changes in driving conditions to produce the control current sufficient to achieve the desired speed. A motor control scheme selection circuit enables the cruise control system to select a current waveform profile appropriate for present driving conditions. A selected current waveform profile is modified, if the control current with the adjusted phase advance angle is not sufficient to achieve the desired speed.

Abstract: A DC motor control device of a water heater includes a fanner control system, a rotation speed detection circuit, and a micro-processing unit. The fanner control system has a DC motor and a control circuit unit. The rotation speed detection circuit is connected to the DC motor for detecting the rotation speed of the DC motor. The micro-processing unit is connected to the output terminals of the rotation speed detection circuit. The output terminals of the micro-processing unit are connected to the fanner control system. The micro-processing unit is to process outputs of the rotation speed detection circuit and then output a low DC voltage to drive the DC motor, thereby having an optimal rotation speed.

Abstract: A motor driving apparatus includes a pulse-width modulator and a PWM frequency switch for switching a carrier frequency of the modulator. The PWM frequency switch changes a carrier frequency in a start-up period of the motor to another frequency when the motor enters into a regular rotation. The carrier frequency in the start-up period is set at a lower level than that in the regular rotation period, so that the driving apparatus can reduce power-loss generated in the start-up period by switching actions of respective driving elements forming a first and a second drivers. In the regular rotation period, the driving apparatus performs PWM-driving with a high enough carrier frequency, so that the motor driven by this driving apparatus can realize accurate rotation.

Abstract: A brushless DC motor control system is arranged to control a command current indicative of a current to be supplied to the brushless motor on the basis of an estimated phase angle and an actual phase angle to control a current supplied to the brushless motor on the basis of an estimated phase angle and an actual phase angle, and to execute at least one of an estimated phase angle returning processing for returning the estimated phase angle and a current lowering processing for lowering a command current, when the estimated phase angle advances relative to the actual phase angle.

Abstract: A method for determining a position of a rotor of a synchronous alternating-current permanent-magnet machine includes injecting a high-frequency voltage superimposed on a voltage delivered by a machine control system; measuring a current of the motor and extracting a current corresponding to the injected voltage; and obtaining, from the injected voltage and from the corresponding current, an electrical angle &thgr; suitable to identify the position of the rotor by using a sine and cosine of twice the electrical angle &thgr; of the machine.

Abstract: A drive circuit including a motor for positioning a damper from a rest position to a stalled position and protect the drive mechanism from damage due to increased current to the drive motor when the damper stalls by including a current limiter to prevent the current in the motor from exceeding a predetermined value.

Abstract: Load fluctuation of a refrigerating cycle under severe conditions needs to be overcome. For instance, a compressor driver which can positively drive the compressor employed even in a vehicle is desirable. To be more specific, at the start of the compressor, a phase of the current flowing in the motor is controlled to be ahead of an induction voltage, then the advancement of the phase is controlled to decrease. Under an unstable condition to detect a position, such as at the start under pressure-difference, the foregoing control allows the phase to advance up to the current-phase where the max. torque can be produced, thereby drawing the instantaneous max. torque of the motor for starting the compressor. Then the control reduces the advancement for obtaining a stable operation. This control method can realize a compressor driver having start-performance enough to overcome pressure-difference.

Abstract: A novel cruise control system is provided for adaptively controlling an electric vehicle to maintain desired speed under variable driving conditions. This system utilizes multiple motor control scheme for controlling the motor using various waveform profiles of the control current, and involves phase advance angle adjustment provided for adaptively controlling a phase advance angle between the control current and back-EMF in response to changes in driving conditions to produce the control current sufficient to achieve the desired speed. A motor control scheme selection circuit enables the cruise control system to select a current waveform profile appropriate for present driving conditions. A selected current waveform profile is modified, if the control current with the adjusted phase advance angle is not sufficient to achieve the desired speed.

Abstract: The aim of the invention is to provide a method, with which the load current and thus the load moment of an asynchronous motor that is controlled via a phase-controlled two-phase thyristor power controller can be easily influenced so as to allow a smooth starting operation. According to a first embodiment of the invention, the ignition point (tIgn+1) is determined in the controlled phase (L1 and L2) in order to adapt the flow angles of the subsequent current half waves. According to a second embodiment, the ignition point (tIgn) of the subsequent current half waves is brought forward in both controlled phases (L1 and L2).

Abstract: A magnitude of current that does not cause electric power generation is supplied to a field winding of a movable element, and an induced voltage generated in a armature winding of a stationary element is measured. A position of the movable element is determined from the measured induced voltage. In addition to the thus-determined position of the movable element, a position of the movable element measured on a different basis is used to measure an error regarding the position of the movable element.

Abstract: A voltage regulator controls an output of an automotive alternator by controlling an amount of excitation current supplied to a field winding of the alternator. The amount of the excitation current is sensed by a sensing resistor as a sensed voltage appearing across the sensing resistor. The sensed voltage is amplified by an amplifier to obtain a detected voltage, an amplifying factor of which is adjusted based on an reference voltage precisely corresponding to the amount of the excitation current, and thereby the detected voltage is equalized to the reference voltage. In this manner, the excitation current is precisely detected without mechanically adjusting a resistance of the sensing resistor by function-trimming or the like.

Abstract: A system and method for predicting mechanical failures in machinery driven by induction motors by using the motor as a diagnostic tool to detect present mechanical disturbances. The motor is monitored during operation to avoid down-time. The motor's torque fluctuations are used as an indicator of early-stage mechanical failures in the machinery. The motor's torque fluctuations are determined using indirect sensing techniques that are less expensive and less intrusive than previously known. More specifically, torque is derived from easily and inexpensively measurable parameters, such as motor slip and phase angle. Current operation is compared to known normal operation. Variations of the motor's characteristics from the known baseline indicate an actual or approaching mechanical failure. “Experimental Fractals” are disclosed that visually represent a current state of the monitored machinery and allow for visual comparison to a baseline for detection of mechanical failures.

Abstract: A control system for a multiphase permanent magnet motor having a controller for producing a control signal to energize each phase winding. The controller includes a current value calculator for determining a value of phase current advanced in phase with respect to back-EMF by a phase advance angle, and a phase advance optimization circuit for producing a value of the phase advance angle optimized so as to maximize output torque of the motor and mimimize the phase current. The phase advance optimization circuit determines the phase advance angle optimized for each phase of the motor.

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 method and system for modifying an estimated rotor angle for improved efficiency in a PMSM drive system. A module monitors a run command, a torque command, and an estimated speed; and in response thereto, generates an output correction angle for modifying the estimated rotor angle. The output correction angle may be added to the estimated rotor angle. The output correction angle may be generated only for predetermined conditions of said run command, torque command, and speed. In particular, the output correction angle may be generated (1) when the run command is asserted, (2) when the torque command is above a predetermined level, and (3) when variations in the speed are within predetermined limits.

Abstract: In an electric motor apparatus of the present invention, both of energized spiral wires 17A and 17B for a first system 18A and a second system 18B cooperate to rotate the rotor 25 in a normal condition, however, when it is happened an abnormal condition in one of the first system and the second system, the energized spiral wires of the other system rotate the rotor 25 so that the present invention can prevent the rotation of the electric motor 14 from stopping just after the abnormal condition in either of the systems to achieve a fail-safe function. Therefore, the present invention can decrease a number of parts in comparison with the conventional apparatus having two actuators to restrain an increase of the cost and to achieve a compact structure.

Abstract: A high phase order induction machine drive system is disclosed. This has an inverter system for the synthesis of a plurality of phases of alternating current output, and a N-phase induction motor (N is greater than 3). The motor is connected to the inverter terminals so that each motor phase is electrically connected to a first inverter terminal and a second inverter terminal S+1 inverter terminals distant from the first inverter terminal in order of electrical phase angle (S is the skip number). The phase angle difference between the pair of inverter terminals to which each motor phase is connected is identical for each motor phase.

Abstract: There is provided a small-sized and slim driving device which is easy to manufacture and capable of producing high output. A magnet has a cylindrical shape, and at least the outer peripheral surface of the magnet is circumferentially divided into n sections magnetized so as to have alternately different poles. The magnet can rotate about a rotational axis of the cylindrical shape. A coil is arranged axially of the magnet and parallel thereto. An outer magnetic pole portion is disposed to be magnetized by the coil, and has a plurality of hair comb tooth-shaped portions opposed to the magnet and arranged around the magnet such that an angle corresponding to the circumferential width of each of the hair comb tooth-shaped portions opposed to the magnet about the rotational axis of the hollow cylindrical shape of the magnet is equal to a predetermined angle A.

Abstract: There is provided a small-sized and slim driving device which is easy to manufacture and capable of producing high output. A magnet has a cylindrical shape, and at least the outer peripheral surface of the magnet is circumferentially divided into n sections magnetized so as to have alternately different poles. The magnet can rotate about a rotational axis of the cylindrical shape. A coil is arranged axially of the magnet and parallel thereto. An outer magnetic pole portion is disposed to be magnetized by the coil, and has a plurality of hair comb tooth-shaped portions opposed to the magnet and arranged around the magnet such that an angle corresponding to the circumferential width of each of the hair comb tooth-shaped portions opposed to the magnet about the rotational axis of the hollow cylindrical shape of the magnet is equal to a predetermined angle A.

Abstract: A method for controlling a synchronous motor driven adjustment device is used in motor vehicles by means of an electronic control, especially for controlling adjustment devices with an anti-trap protection and/or with an excess force limitation. The method includes evaluating variables correlating to the dynamics of the adjusting device or the position of the adjustment member and generating control signals based on the variables, controlling the adjustment rate of the adjustment member to a constant value, and setting a phase displacement between an exciting field and a rotating field of the motor to provide torque to the drive unit based on the load angle at which the torque reaches a maximum.