Abstract: The present invention provides a motor drive apparatus which improves a trade-off relation between a stable position detection and noise at its driving. A sensorless drive operation circuit calculates by operation a zero cross point (point p) of a voltage of a position detection phase at the next interval, using time information measured based on an output signal from a comparison circuit at the previous interval and the present interval. After the point p has been calculated, points a and b are detected by interrupting a predetermined time drive current.

Abstract: An electric drive which has an inductor with poles, an armature having a plurality of windings and rotatable relative to the inductor and its poles, and a control unit which, when a respective one of the windings of the armature approaches a respective one of the poles of the inductor, turns off a voltage supply to the winding so that when the winding passes the pole it does not have a voltage, and when the winding moves away from the pole the control unit supplies opposite voltage to the winding, and therefore no counter electric motive force is generated during the operation of the electric drive.

Abstract: A steering control system and method for automated steering of work vehicles that adapts to nonlinearities and uncertainties of steering mechanisms including a tolerance control law, a dynamic control law, and a saturation control law selected and executed in real time based on the magnitude of steering angle error, steering mode command, and manual override signal in real time. The dynamic control law includes a dynamic compensator having a double compensation zero, an integral, and a compensation gain, and further includes a deadband compensator and a control signal limiter.

Abstract: An exemplary power system may include an electric machine with multiple sets of stator windings, each set of windings being coupled through a separate switch matrix to a common voltage bus, and each of which may be spatially arranged in full pitch around the stator such that stator flux harmonics are substantially reduced. The reduced stator flux harmonics may be associated with phase current harmonic content. In an example application, such power systems may operate in a generating mode to transfer mechanical energy to electrical energy on a DC voltage bus. In some illustrative embodiments, the power system may provide both high-power and high-speed (e.g., 1 MW at 8000 rpm or above) motoring and/or generating capability suitable, for example, for on-board (e.g., marine, aviation, traction) power systems.

Abstract: A circuit for controlling a voice-coil motor (VCM) may incorporate a pulse-width modulation driver to drive the VCM, a zero-current detector to determine whether the current across the VCM is zero, and a Back-EMF voltage detector to measure the voltage across the VCM when the current across the VCM is determined to be zero. The circuit may determine the current velocity of the VCM and use this information to control the velocity of the VCM.

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: A control system and method for a multi-phase motor substantially reduces or eliminates jitter resulting from drive mismatch by replacing a conventional trapezoidal drive profile with a drive profile that causes the voltage applied across active phases of the motor to match the back-EMF across those phases. In an ideal motor, the back-EMF is substantially sinusoidal, and although the drive profile applied to each phase is not truly substantially sinusoidal, the drive voltage across the active phases is substantially sinusoidal. In a non-ideal motor, the back-EMF is not truly sinusoidal and the drive profiles applied to each phase are calculated to cause the drive voltage across the active phases to match the back-EMF across those phases.

Abstract: A control device for controlling a recovery from a locking of a motor includes: a switching unit which supplies a motor current from a current supplying unit to the motor; and a driving control unit which supplies a PWM control signal to the switching unit to control a driving of the switching unit. The driving control unit supplies the PWM control signal with a low duty ratio lower than a regular duty ratio to the switching unit when the locking of the motor is detected depending on a variation in temperature of the switching unit. The driving control unit supplies the PWM control signal with the regular duty ratio to the switching unit when a cancel of the locking of the motor is detected depending on a variation in inter-terminal voltage of the motor.

Abstract: A method for testing a motor having a rotor and a winding is provided. The method includes steps of (a) providing a power to rotate the rotor to a predetermined speed, (b) removing the power, (c) measuring a terminal voltage of the winding while a current within the winding is zero, (d) obtaining a back electromotive force in the winding by compensating the terminal voltage with a performance of the rotor, (e) selecting a characteristic of the back electromotive force and (f) determining a magnetization of the motor by comparing the characteristic with a predetermined parameter.

Abstract: A submersible motor is provided for a submersible pump, the motor being configured as a single-phase asynchronous motor, which includes a main winding (6), an auxiliary winding (8), and a starting device (10, 14, 16, 18, 20, 22) for controlling the starting procedure of the submersible motor. The starting device (10, 14, 16, 20, 22) for the control of the current feed of the auxiliary winding (8) includes at least one electronic switch (20) in the circuit of the auxiliary winding (8).

Abstract: A power limiting system for multiple electric motors includes an electrical power generating component, such as an alternator, and a plurality of motor controllers connected to an electrical bus. Each motor controller compares the voltage on the bus to a specified minimum voltage and a specified maximum voltage, and reduces its electric power output if the voltage on the bus is less than the maximum voltage while continuing to operate the electric motors.

Abstract: A method and apparatus for electronic control of a direct current motor is disclosed based upon a sensorless commutation technique using voltage vector analysis. A voltage vector is produced by addition of supply phase voltage vectors of energized windings with the back-electromotive force vector of the unenergized winding. The resultant voltage vector rotates at the same speed as the rotor and possesses rotor position information used to commutate phase windings. The angle that the resultant voltage vector makes with the real axis is measured to commutate the phase windings. By parking the rotor in a predetermined position, this technique can be used to efficiently start the motor from rest and commutate phase windings during normal operation.

Abstract: Devices and methods for performing dynamic sampling of a back electromotive force (BEMF) measurement are provided. A device has hardware, including a voice coil motor (VCM) for receiving a VCM command signal and a correction circuit, for obtaining the VCM command signal and a coil voltage measurement from the hardware, where the correction circuit removes a transient voltage measurement due to a change in the VCM command signal from the coil voltage measurement and outputs an estimated BEMF measurement.

Abstract: A circuit for indirectly measuring a sign of a current flowing in an inverter stage coupled to a phase of a motor or indirectly measuring the sign of the voltage induced by a counter Electromotive Force (EMF) in a coil of the phase of the motor, the inverter stage being connected between a power supply and the ground. The circuit includes a gate driver circuit coupled to the inverter stage for alternatively connecting the phase of the motor to the power supply and to ground, the gate driver circuit having a current sign detection circuit, wherein the current sign detection circuit senses the sign of the current flowing in the inverter stage, or the sign of the counter EMF for controlling the commutation of switches in the inverter stage.

Abstract: In a semiconductor integrated circuit device of the invention, a plurality of external terminals include: a first external terminal (VCC, U, V and W terminals in the FIGURE) receiving a higher voltage than the other external terminals; and a second external terminal (FG terminal in the FIGURE) arranged adjacent to the first external terminal as one of the other external terminals, the second external terminal feeding out, from one end of a transistor Q1, a control pulse signal corresponding to the turning on and off of the transistor Q1, and the second external terminal is connected to an overvoltage protection circuit (consisting of R1, R2, Q2 and AND) that masks a control signal for turning on and off the transistor Q1 so that, when a voltage at the second external terminal reaches a predetermined threshold, the transistor Q1 is kept off all the time.

Abstract: A brushless DC motor operated by a microcontroller has a unique pole construction that enables it to reliably start and operate as a unipolar device so that a reduced number of electronic power switches can be used to reduce cost and complexity. The microcontroller calculated rotor position to eliminate the need for a separate sensor and thereby further reduce manufacturing cost.

Abstract: Controlling and adjusting of the operation of a device actuated by an electric motor are carried out by shutting down the electric power supply of said electric motor at a plurality of time intervals during the motor operation, measuring in the time interval the voltage supplied by the electric motor, comparing the value of the measured voltage with a reference value and, if required on the basis of said comparison, varying at least one parameter related to the functioning of the device in order to compensate possible deviations.

Abstract: The open/close body drive device is capable of restarting a brushless motor, without using magnetic pole sensors, so as to securely drive an open/close body in an arbitrary direction when any of the magnetic pole sensors has failed. When a CPU (1) detects an abnormal logic as a detection pattern of the magnetic pole sensors (9), the CPU (1) determines that the sensor has failed and temporarily stops drive of a DC brushless motor (5), and a motor drive unit (4) generates a phase switching signal to prolong one of electric connection patterns for performing sensorless drive when restarting the DC brushless motor (5).

Abstract: A method and an apparatus to control a disc drive, and more particularly, a method and an apparatus to control a disc drive using a counter-electromotive force, prevents collision and malfunction of a transducer and a disc by determining external vibrations and magnitude of a shock without installing an additional shock sensor in the disc drive. The method of controlling the disc drive using a counter-electromotive force includes detecting a voltage applied to a spindle motor during a predetermined mode, performing an operation of a value of the counter-electromotive force using the detected spindle motor voltage comparing the value of the counter-electromotive force operated with a predetermined threshold, and when the value of the counter-electromotive force is equal to or larger than the predetermined threshold, controlling a voice coil motor and a spindle motor so that a current mode is stopped and a parking or unloading mode is executed.

Abstract: An apparatus for controlling an operation of a compressor includes: a back electromotive force calculator for calculating a back electromotive force of a compressor based on a value of a current applied to a motor of the compressor and a value of a voltage applied to the motor of the compressor; an operation frequency reference value determining unit for detecting a mechanical resonance frequency of the compressor based on the back electromotive force value and the current value and determining the detected mechanical resonance frequency as an operation frequency reference value; and a controller for varying an operation frequency of the compressor according to the determined operation frequency reference value.

Abstract: A method and system for providing sensorless brushless DC motor control using predictive switch timing requires connecting a stator coil in a bridge configuration, applying a positive excitation voltage across the coil for a predetermined time period, deactivating the excitation voltage, and monitoring the voltage (VEMF) generated due to electro-motive force (EMF) across the coil. The polarity of VEMF changes when the rotor has moved a known distance—typically 90°. After detecting a polarity change, a negative excitation voltage is applied across the coil, deactivated, and VEMF monitored to detect a polarity change. This sequence is repeated to maintain the rotation of the rotor. The motor is preferably set into motion using a start-up routine, which also determines the predetermined time period used during steady-state operation.

Abstract: In a semiconductor integrated circuit device of the invention, a plurality of external terminals include: a first external terminal (VCC, U, V and W terminals in the FIGURE) receiving a higher voltage than the other external terminals; and a second external terminal (FG terminal in the FIGURE) arranged adjacent to the first external terminal as one of the other external terminals, the second external terminal feeding out, from one end of a transistor Q1, a control pulse signal corresponding to the turning on and off of the transistor Q1, and the second external terminal is connected to an overvoltage protection circuit (consisting of R1, R2, Q2 and AND) that masks a control signal for turning on and off the transistor Q1 so that, when a voltage at the second external terminal reaches a predetermined threshold, the transistor Q1 is kept off all the time.

Abstract: There is provided a brushless motor drive control circuit capable of assuring an S/N ratio of a predetermined counter electromotive voltage and suppressing lowering of efficiency of a brushless motor at a high-speed rotation.

Abstract: A method of controlling a brushless direct current motor without a position sensor. The motor includes a plurality phase windings adapted to be energized by an active inverter circuit that synchronously applies drive voltages through a plurality of phases to produce drive currents in the phase windings. Back electromotive force voltages are detected when the inverter circuit is inactive for sensorless detection of motor position.

Abstract: Disclosed herein is a control method of a sensorless brushless direct current (BLDC) motor, and more particularly, a drive control method of a concentrated winding BLDC motor which prevents shutdown due to failures of detection of zero cross points (ZCPs). A reference voltage inputted to comparators is altered to set new reference points. ZCPs are detected using the new reference points to avoid uneven detection of the ZCPs. Phase commutation is corrected corresponding to the ZCPs detected using the new reference points to reduce current ripple, thereby leading to stable control of the sensorless BLDC motor. To this end, the control method adds or subtracts a preset certain value to/from a reference voltage to produce a new reference voltage, and detects ZCPs with respect to the new reference voltage to control drive of the sensorless concentrated winding BLDC motor.

Abstract: A method to determine a back electromotive force induced in a coil of a voice-coil motor by its motion. The motor is driven in a discontinuous mode by commanding alternating on-phases and off-phases (tristate). A drive current flowing in the coil or a drive voltage on the coil at an end of an on-phase is sensed. An amplitude of a voltage disturbance induced in the coil by mutual induction between a permanent magnet of the voice-coil motor and the moving coil as a function of the sensed drive current or drive voltage is estimated. Voltage on the coil is sensed during a following off-phase with no current flowing in the coil. The back electromotive force induced in the moving coil is determined as a difference between the sensed voltage and the estimated amplitude of the voltage disturbance.

Abstract: Disclosed is an apparatus, controlling the number of rotations per minute of a brushless DC motor, the apparatus comprising: a brushless DC motor that rotates at a constant speed when a rotation current is applied, and stops rotating when a stop current is applied; a pulse applying unit that outputs input pulses according to a pulse apply frequency, which is predetermined or inputted by a user; a rotation detecting unit that detects the number of rotation pulses, and outputs a predetermined output signal per rotation of the brushless DC motor; and a current controlling unit that applies the rotation current to the brushless DC motor in correspondence with the input pulse, and the stop current to the brushless DC motor in correspondence with the output signal.

Abstract: A method and apparatus are provided for providing one or more brushed motor control signals for controlling the operation of a brushed motor, including a signal for disconnecting the power applied to the brushed motor so that the brushed motor can provide a brushed motor signal containing information about a collective back EMF from all poles of the brushed motor; and responding to the brushed motor signal, measuring the collective back EMF of the brushed motor, and providing the one or more brushed motor control signals for controlling the operation of the brushed motor.

Abstract: A technique for determining an alignment error of a Hall sensor location in a brushless DC motor drive, by measuring the back EMF waveform, preferably while the motor is coasting. According to the technique, an angular offset is calculated between a selected BEMF waveform and a selected Hall signal. Such offsets are preferably calculated for each phase individually. The offsets may be advantageously stored in the motor control unit and used to adjust the output motor control signals for maximum torque.

Abstract: The present invention is a motor control device comprising a control system, the control system being capable of controlling the motor by PWM and having integration means being capable of outputting an integrated value obtained by integrating a deviation between a rotation speed and a target rotation speed of a motor, the motor control device being capable of starting control with the control system for causing the motor to rotate at the target rotation speed after rotation of the motor has been started. In this motor control device, an output value of the integration means at a time when control with the control system is to be started is set to have a value that corresponds to a counter electromotive force generated in the motor by its rotation.

Abstract: When multiple motors (40) share a common DC power supply (10) via a bus (20), a system and method is provided for managing the effect of regenerative energy caused by a motor. The regenerative energy may be sensed, e.g., by a power electronics controller (50, 50?). In response, one or more of the other motors currently in operation may be controlled to operate according to a reduced power factor. Thus, the excess energy is consumed without adding any new components or increasing the amount of work performed in the system.

Abstract: A system, apparatus, and method (10) for detecting an electrical short condition in a dynamoelectric machine are described. The method includes determining an operating parameter of a dynamoelectric machine (14) responsive to at least one output signal of the dynamoelectric machine and providing a transfer function (16) for predicting a field current of dynamoelectric machine. The method also includes obtaining a value for a predicted field current (18) of the dynamoelectric machine from the transfer function and the operating parameter and identifying a shorted turn condition of the dynamoelectric machine responsive to a difference between the value of the predicted field current and a value of an actual field current of the dynamoelectric machine (24).

Abstract: A barrier operator comprises a first measuring apparatus for measuring a current used by a direct current (dc) motor to move a barrier and a second measuring apparatus for measuring a generated voltage of the dc motor. A controller is coupled to the first measuring apparatus and the second measuring apparatus. The controller is programmed to calculate a torque of the dc motor by using the current and to determine when an obstruction exists in the path of the barrier based upon the calculated torque.

Abstract: An apparatus and a method for controlling operation of a reciprocating compressor is capable of reducing a stroke estimation error by eliminating an error that occurs due to resistance and inductance of a compressor motor by estimating a stroke with a counter electromotive force induced by a searching coil. Furthermore, by leaving errors of inductance and resistance, among all motor parameters, out of consideration in stroke estimation, a stroke estimation error can be reduced.

Abstract: A prior art direct back EMF detection method synchronously sampled motor back EMF during PWM “off” time without the need to sense or re-construct the motor neutral in a sensorless brushless DC (BLDC) motor drive system. Since this direct back EMF sensing scheme requires a minimum PWM “off” time to sample the back EMF signal, the duty cycle cannot reach 100%. Also in some applications, for example, high inductance motors, the long settling time of a parasitic resonant between the motor inductance and the parasitic capacitance of power devices can cause false zero crossing detection of back EMF. An improved direct back EMF detection scheme samples the motor back EMF synchronously during PWM “on” time at high speed. In the final system the motor back EMF can be detected during PWM “off” time at low speed, and it is detected during PWM “on” time at high speed.

Abstract: A control unit for driving a regulating transistor (2) of a fan arrangement, in which the regulating transistor (2) is connected in series with an electronically commutated fan (1), having control means (5, 6, R1, R2) for the analog driving of the regulating transistor (2) with a control signal (Ucontrol) in a manner dependent on a control input voltage (Uin). The control unit comprises compensation means (R3, R4) for influencing the control signal (Ucontrol) in a manner dependent on an AC voltage component (UAC) of an operating voltage (UB) of the fan arrangement, so that the AC voltage component (UAC) of the operating voltage (UB) is completely or partially compensated for in a voltage across the fan (1).

Abstract: A vibration linear actuating device includes a vibrating linear actuator and a driver (52) for driving actuator. Actuator includes mover having permanent magnet magnetized in a radial direction, stator having coil (2) and facing the permanent magnet, and elastic body for coupling stator to mover. The driver includes driving section having switching element (Q5) for powering coil (2), output controller (27) for controlling switching element (Q5), zero-cross detector (25) for detecting a zero-cross point of back electromotive force generated in coil (2) and having an output to be fed back to the output controller (27). In this structure, the driver powers coil (2) in one way to keep mover vibrating in corporation with elastic body.

Abstract: A brushless DC motor is disclosed, in which a commercial AC source is full-wave rectified by a rectifier and then converted into a generally flat and low DC voltage not more than 45V by a DC voltage converter. The low DC voltage is applied in a full-wave driving method to a stator coil via an inverter circuit formed of switching elements in a bridge configuration. This structure allows obtaining the brushless DC motor coupled directly to the AC source, and the torque ripples and uneven rotation of the motor are suppressed.

Abstract: A method and an arrangement for protecting a frequency converter in a system comprising a motor and a frequency converter supplying it via a bipolar or multipolar supply connection, the arrangement comprising first connecting means adapted to couple poles of the supply connection mutually substantially into short-circuit in response to a detection of a fault in the frequency converter.

Abstract: A method for sensing a back electromotive force induced in a winding of a voice coil electro-mechanical actuator controlled in a discontinuous mode by alternating conduction phases to off-phases includes sensing voltage at terminals of the winding during an off-phase The winding is driven during a conduction phase immediately preceding the off-phase to invert, during a final portion of the conduction phase before entering an off-phase, a direction of flow of the current through the winding.

Abstract: Techniques sense a back-emf voltage from a brushed permanent magnet motor. Such techniques can be used for a variety of purposes, such as to estimate the current that is being applied to the motor, to estimate the motor's velocity, position, torque, and the like. One aspect of the invention includes the deactivation of power applied to the motor, and the monitoring of the back-emf of the voltage while power is not applied.

Abstract: A battery operated industrial truck with at least one first motor and at least one second motor, which are operated by one electric control or regulation device for each motor, which are realised such that the motors can be operated as generators in order to feed back electric energy into the battery, characterised in that a device for switching excess voltage is provided, which in the generator mode of one of the motors temporarily connects the respective other motor to it as a load when a measuring device measures a condition in which an excess voltage occurs or may occur.

Abstract: A low noise electronic three phase bridge controlled brushless DC motor suitable for whiteware appliance pumps and other appliance applications. Back EMF zero crossing sensing is used to determine rotor position and thus stator winding commutation times. Motor torque and speed are controlled by pulse width modulating the operation of that bridge switching device which has just been switched from an OFF state to an ON state on each new commutation. All three stator windings have current flowing in each winding commutation to improve motor current waveform and thereby reduce motor noise, but the current in one winding is always terminated before the end of the commutation period to allow the back EMF in that winding to be sensed to zero crossing.

Abstract: A motor controller comprising, a detector configured to perform a difference processing for information relating to a counter electromotive force and an induced electromotive force generated by a stepping motor, and to generate a driving control signal based on a result of the difference processing, and a driver configured to drive the stepping motor based on the driving control signal.

Abstract: A motor driver drives a motor composed of a rotor and plural-phase windings that generate a magnetic field for rotating the rotor, including: a plurality of transistors that operate as switches for supplying current to the windings; a position detector operable to detect a rotational position of the rotor, based on a terminal voltage of each winding; and a switching controller operable to have performed a switching method to turn the transistors to an ON state or to an OFF state for controlling the rotor at the predetermined speed by means of the position detector, wherein the switching controller further controls so as to force each of the transistors into the OFF state for a predetermined duration in a predetermined cycle, and the position detector detects only while the switching controller forcedly keeps the transistor in the OFF state.

Abstract: An electronic control unit for producing a sufficiently boosted voltage even when a supply voltage becomes high includes an inverter that drives switching elements and converts a DC voltage into an AC voltage, and booster means which boosts a DC voltage that is input into a voltage to lie within a voltage range in which a voltage necessary for driving the switching elements is a lower-limit value and a maximum boosted voltage is an upper-limit value, and outputs the boosted voltage to the inverter.

Abstract: A motor control system for a brushless and sensorless DC motor for driving a compressor, pump or other application, includes a protection and fault detection circuit for detecting a locked rotor and a rotor which has stopped because of lost rotor phase lock. The motor control system also includes an off-the-shelf motor control integrated circuit having an input for disabling power outputs to the motor phase coils. The protection and fault detection circuit uses a back EMF sampling circuit coupled to the motor phase coils and momentarily disables power to the motor phase coils, via the motor control integrated circuit input, to determine if the motor rotor is rotating. The system also monitors supply voltage, supply current, temperature, and motor speed limits to detect faults and protect system components.

Abstract: A single phase motor driving unit includes: a first driving transistor supplying a single phase coil with a driving electric current in a certain direction; a second driving transistor supplying the single phase coil with a driving electric current in the opposite direction; a comparison section comparing an intensity of a sine wave signal obtained from a Hall device detecting a rotational position of a single phase motor and a reference value, and generating a timing signal in a predetermined period starting immediately before and ending immediately after a point at which the direction of the driving electric current for the single phase coil changes; and a recirculating section recirculating the driving electric current by controlling ON-OFF timings of the first and the second driving transistors in the predetermined period in which the timing signal is generated such that, within a given period in which the first and the second driving transistors on the side to which the driving electric current flows out

Abstract: A system and a method for starting a brushless DC motor are provided. The method includes applying commutation pulses to at least two phase coils to induce a rotor to rotate to a starting position and then de-energizing the at least two phase coils. The method further includes applying commutation pulses to at least two phase coils to induce the rotor to rotate from the starting position in a predetermined direction. The method further includes de-energizing all phase coils for a first time interval after the rotor is rotating and sampling a back EMF signal in at least one of the phase coils to determine a first value indicative of an electrical period of the back EMF signal or a portion of an electrical period of the back EMF signal. Finally, the method includes applying commutation pulses to at least two phase coils for a second time interval, the second time interval being based on the first value.

Abstract: A drive circuit for operating a resonant motor includes a motor circuit, a feedback circuit, a control circuit, and a coil drive circuit. A feedback loop includes the motor circuit, the feedback circuit, and the control circuit. The feedback loop in conjunction with the coil drive circuit monitors, maintains, and adjusts the oscillatory motion of the resonant motor. The drive circuit is suitable for operating a resonant motor of an optical code reader.