Abstract: A motor controlling device is provided that controls a brushless motor having a plurality of phases based on magnetic pole signals output by a plurality of magnetic pole signal output sections each corresponding to one of the phases. The motor controlling device includes an abnormality determining section, a signal generating section, and a motor controlling section. The abnormality determining section determines whether a magnetic pole signal output by each magnetic pole signal output section is an abnormal magnetic pole signal. When the abnormality determining section determines that at least one of the magnetic pole signals is an abnormal magnetic pole signal, the signal generating section generates a simulated signal corresponding to the abnormal magnetic pole signal based on the normal magnetic pole signals other than the abnormal magnetic pole signal and the rotational state of the brushless motor.

Abstract: A driving device is provided for controlling rotation of a motor. The driving device comprises an inputting module, a comparing module and a processing module. The inputting module includes a first current source, a first voltage source and a first capacitance. The first capacitance is coupled between the first current source and the first voltage source for charging/discharging and generating a voltage signal. The comparing module is coupled to the inputting module for comparing a selecting signal with the voltage signal and generating a comparing signal. The processing module is coupled to the comparing module and generates a control signal according to a clock signal and the comparing signal, wherein the driving device controls the rotation of the motor by the control signal.

Abstract: An object of the present invention is to provide a motor driving device capable of outputting an accurate rotation signal while preventing a false detection of B-EMF in a position detecting comparator. The motor driving device includes an output circuit, filter circuit, comparison circuit, current zero ampere detecting circuit, position detecting circuit, sensorless drive arithmetic operation circuit, noise reduction current waveform generating circuit, signal synthesizing circuit, and output transistor control circuit, the comparison circuit including a comparator, polarity switching portion connected to a + terminal and ? terminal of the comparator and signal switching portion, the comparator being structured to be able to set and release an offset having a predetermined voltage value set preliminarily.

Abstract: A motor control apparatus includes a phase sensing circuit, a current sensing circuit, a phase lock loop, a controller and a driving circuit. The phase sensing circuit detects a phase switching state of a magnetic pole of a motor circuit, and then generates and outputs a phase switching signal to the phase lock loop when the motor is operating. The current sensing circuit detects a current flowing through a coil of the motor to generate and output a current phase signal to the phase lock loop. The phase lock loop compares a phase difference between the phase switching signal and the current phase signal to generate and output a phase-switch controlling signal to the controller. The controller generates and outputs a driving signal to the driving circuit in accordance with the phase-switch controlling signal. The driving circuit controls the phase switching state of the magnetic pole of the motor to drive the motor to rotate in accordance with the driving signal.

Abstract: A motor driving apparatus has a loss-of-synchronism monitoring circuit that monitors the rotation of a rotary machine such as a brushless DC motor to detect a sign of transition to a state of loss of synchronism. When the sign is detected, an energization control circuit temporarily stops driving of the rotary machine to bring it into a free running state, and thereafter carries out control so as to resume driving of the rotary machine. Further, the motor driving apparatus has an inverter and a drive control circuit that controls switching operation of the inverter based on rotation of the rotary machine.

Abstract: A brushless motor control apparatus includes a mask processing unit to which digital induced voltage signal is input, a energizing current timing generation processing unit, a pulse width detection unit, and an advance angle correction unit for performing advance angle correction. The pulse width detection unit measures pulse width of spike voltage, and the advance angle correction unit calculates the correction to the advance angle according to the length of this pulse width. The energizing current timing generation processing unit takes half the value obtained after subtracting the correction value from the edge interval of the position detection signal generated in the mask processing unit as the advance angle.

Abstract: A semiconductor integrated circuit for sensorless driving of a brushless motor, has: an induced voltage detecting circuit which includes a comparator for comparing a voltage induced in an exciting coil by a rotation of a rotor of the brushless motor with a midpoint voltage of the rotor of the brushless motor and outputting a detection signal corresponding to a comparison result, and detects a zero cross point where the induced voltage crosses the midpoint voltage; a logic circuit that outputs a control signal for controlling the brushless motor, in response to a command signal for regulating an operation of the brushless motor and an output signal of the comparator; and a power transistor circuit that supplies a driving current to the exciting coil.

Abstract: This invention relates to a method of speed control selection for an electronically commutated motor comprising the following steps: (a) a motor controller receives an input signal T from a speed control selection circuit; (b) the motor controller retrieves a corresponding value for a motor running speed S from a comparison list correlating the input signal with the motor running speed, which list has been stored in the motor controller in advance, by searching the comparison list for the input signal T; and (c) the motor controller controlling a motor M to run at the motor running speed S, achieving the purpose of the speed selection. This method allows for from 2 to 256 speed choices with a single signal wire only. Such a circuit structure has the advantages of high integration, simple wiring, low cost, good performances, low failure rate, higher number of optional speeds, and simpler and more practical control.

Abstract: A control and motor arrangement in accordance with the present invention includes a motor configured to generate a locomotive force for propelling the model train. The control and motor arrangement further includes a command control interface configured to receive commands from a command control unit wherein the commands correspond to a desired speed. The control and motor arrangement still further includes a plurality of detectors configured to detect speed information of the motor, and a process control arrangement configured to receive the speed information from the sensors. The process control arrangement is further configured and arranged to generate a plurality of motor control signals based on the speed information for controlling the speed of said motor. The control and motor arrangement yet still further includes a motor control arrangement configured to cause power to be applied to the motor at different times in response to the motor control signals.

Abstract: A method ascertains a correction value for the angle of the rotor of an electrically commuted reversible synchronous motor relative to a sensor used for the activation thereof. In order to equalize the sensor and recognize and correct electrical incorrect angles and incorrect controls, the motor is activated in a calibration journey using an externally forced rotating field. The electrical angle of the rotating field and the mechanical angle of the rotor are measured simultaneously by the external sensor on at least one reference position during the calibration journey and stored associated with one another as a measurement series of value pairs. The electrical angle of the rotating field and the mechanical angle of the rotor, which is measured by the sensor, are also detected simultaneously after direction reversal of the rotating field. These are stored associated with one another as a second measurement series of value pairs.

Abstract: A pulse generation unit generates a PWM signal whose duty ratio changes according to a target torque of a motor. A back electromotive detection circuit compares a back electromotive voltage generated at a coil of the motor with a middle point voltage of the coil, and outputs a back electromotive detection signal that becomes high level at a timing of the zero crossing point. A phase adjustment unit compares phases of the back electromotive detection signal and a reference signal that becomes a predetermined level at a predetermined timing, and adjusts the duty ratio of the PWM signal by feedback so that the phase error becomes a minimum. A frequency adjustment unit adjusts the frequency of the PWM signal such that the frequency of the PWM signal becomes integral multiples of the frequency of the back electromotive detection signal.

Abstract: A circuit system and process utilizes back electromotive force (BEMF) voltage to assist in safe power down of devices, such as the read/write head in from low factor disk drives or similar devices. The BEMF voltage from a motor device, such as a spindle motor utilized in a circuit using negative voltage to drive some switches, such as positive channel metal oxide semiconductor (“PMOS”) driver transistors, to reduce and/or effectively minimize the on-resistance of the switches while delivering the current from BEMF voltage of the motor to another device, such as a motor that retracts controls a read/write head.

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: A system includes a power control module, a period determination module, and a control module. The power control module controls current through stator coils of a motor to rotate a rotor. The period determination module determines a first length of time between a first set of induced stator coil voltages and determines a second length of time between a second set of induced stator coil voltages. The control module determines whether an external disturbance disturbs rotation of the rotor based on a difference between the first and second lengths of time.

Abstract: A motor controller for a direct current motor includes a first node receiving first PWM signals having a duty cycle indicative of a desired rotational speed of said motor and an input node receiving second digital signals, the frequency of said second signals indicative of the rotational speed of said motor. A frequency-to-PWM circuit is coupled to the input node to provide second PWM signals having a duty cycle corresponding to the rotational speed of the motor. A duty cycle comparator has a first input coupled to the first node and a second input coupled to the second node to generate a control signal for controlling the rotational speed of the motor.

Abstract: A motor drive circuit includes a first amplifier circuit to amplify a difference between first and second position detection signals with a gain becoming smaller according to drop in power supply voltage, to output a first amplification signal, the first and second position detection signals being signals indicating a rotational position of a rotor in a motor, having a frequency corresponding to a rotation speed of the motor, and being opposite in phase to each other; a second amplifier circuit to amplify the difference between the first and second position detection signals with the gain, to output a second amplification signal opposite in phase to the first amplification signal; and a drive circuit to amplify the difference between the first amplification signal and the second amplification signal with a predetermined gain to be saturated at the power supply voltage, to output a driving voltage for driving the motor.

Abstract: A circuit is adapted to activate a writer head of a data storage media drive during both the boost periods as well as the steady state periods. The current supplied to the writer head during the boost periods exceeds the steady state current and flows between positive and negative voltage supplies so as to provide the required magnetic flux change in the inductor disposed in the write head. During the steady state periods, a switch circuit is turned on to provide a second current path across the writer head. During the steady state periods, the current flows between the positive voltage supply and the ground to reduce power consumption. The switch circuit is turned off during the boost periods.

Abstract: A drive device having an electric motor with a device for field oriented control of the electric motor and a method for operation thereof is disclosed. An error monitoring of a transducer on the electric motor is achieved by a comparator device for comparing a transducer signal of the transducer on the electric motor with a calculated parameter of the field oriented control, the comparator device recognizing a transducer error and/or a coupling error. The coupling error relates to a coupling for mounting the transducer on the electric motor.

Abstract: A drive, including an electric motor, which is supplied by a rectifier, the rectifier including a time-discrete closed-loop control structure, which regulates the stator current of the electric motor by setting the voltage applied at the motor, the current of the motor being acquired in time-discrete fashion, the closed-loop control structure including a first closed-loop controller whose setpoint is the output value of a first non-linear transfer member, and whose actual value is the output value of a second non-linear transfer member, the input value of the first non-linear transfer member being the setpoint of a first current component of the current, the input value of the second non-linear transfer member being the actual value of a first current component of the current.

Abstract: An electric power steering device that can estimate an ambient temperature and apply current limiting without using ambient temperature detecting means is provided. The electric power steering device includes a motor that supplements the driver's steering force, a controller that determines and controls the quantity of current passed to the motor, and vehicle speed detecting means. The electric power steering device includes ambient temperature estimating means provided with a vehicle speed signal input from the vehicle speed detecting means and limits the quantity of current passed to the motor according to an output from the ambient temperature estimating means.

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: A motor drive method which supplies a drive current in a pulse form to a multiphase motor, to drive the motor. The motor drive method includes the steps of: generating a pulse signal having a duty ratio in accordance with torque, alternately repeating an ON time-period and an OFF time-period in accordance with the pulse signal, to supply a drive current in a pulse form to a phase coil currently driving, interpolating back electromotive voltage of the OFF time-period (Toff), using a back electromotive voltage (Vu) of the ON time-period (Ton), with respect to the back electromotive voltage (Vu) occurring in at least one coil of the multiphase motor, to generate an interpolated virtual back electromotive voltage (Vu?), detecting a zero-cross point, by comparing the interpolated virtual back electromotive voltage (Vu?) with a midpoint voltage (Vcom) of the coil, to generate a BEMF detection signal (BEMF_EDGE), and switching a phase to be driven, based on the BEMF signal (BEMF_EDGE).

Abstract: In one aspect, a control circuit to control a speed of a motor includes a PWM oscillator configured to generate a PWM output signal having a duty cycle. The speed of the motor is controlled by the PWM output signal to be proportional to the duty cycle. The control circuit also includes a duty cycle control circuit responsive to a duty cycle selection signal and coupled to the PWM oscillator. The duty cycle control circuit is configured to compare a voltage reference and a supply voltage. The duty cycle control circuit controls the duty cycle of the PWM output signal to be inversely proportional to the supply voltage.

Abstract: A control circuit (150) for controlling the current supplied to a winding strand (102) in an electric motor (143). The control circuit comprises at least one semiconductor switch (106) and a control unit (108) for controlling the semiconductor switch(es). Each semiconductor switch (106) is connected to a respective winding strand (102), in order to control the current in said winding strand. The control unit (108) comprises an output (110) for applying a control signal (CTRL) to the semiconductor switch (106), and is configured to set the output (110), at least upon switch-off of the semiconductor switch (106), to high impedance in order to prevent a voltage at the control unit output from influencing, during the switch-off operation, a signal input at the semiconductor switch (106). The improved control circuit increases motor efficiency and reduces commutation noise.

Abstract: The invention relates to a method for operating an actuating drive having an electrically commutated motor 1 for adjusting an actuating member, having a position sensor 6 for detecting the rotary angle position of the rotor of the motor or of an element which can be driven in a rotatable manner by said motor. A motor control unit 9 serves to commutate the motor 1 and to regulate the position of the actuating member, it being possible to supply position signals, which correspond to the position values detected by the position sensor 6, to the motor control unit 9. After the actuating drive is started, uncompensated measured values are detected by the position sensor 6 over at least one full revolution of the rotor or of the element which can be driven in a rotatable manner; corresponding correction values for compensating angle errors are formed in a compensation unit 11.

Abstract: A brushless motor controller for use in a fuel pump detects a rotor phase based on an induced voltage in each phase coil of a brushless motor, and controls energization of the each phase coil based on the detected rotor phase. A control circuit of the controller is arranged to check the induced voltage by using three reference voltages as judgment values, convert a result of the check into a logic signal, and detect the rotor phase based on a prescribed change of the logic signal.

Abstract: A low speed region position estimating portion is designed to be suitable for when the motor is operating in a low speed region, and estimates a low speed estimated rotational position ??L. A high speed region position estimating portion is designed to be suitable for when the motor is operating in a high speed region, and estimates a high speed estimated rotational position ??H. A dividing portion obtains a divided estimated rotational position ??M by internally dividing the low speed estimated rotational position ??L and the high speed estimated rotational position ??H. A rotation speed calculating portion obtains a rotation speed ? of a rotor based on an output signal from a steering sensor. The rotational position of the rotor is then obtained by selecting one of i) the low speed estimated rotational position ??L, the high speed estimated rotational position ??H, or the divided estimated rotational position ??M, based on that rotation speed ?.

Abstract: A peak hold circuit is provided that operates stably even if a peak voltage to be held of a motor-drive-current detection voltage is minute. The peak hold circuit includes: a level shift circuit shifting the motor-drive-current detection voltage by a given voltage; a differential amplifier circuit receiving an output voltage of the level shift circuit and a voltage at an output terminal to amplify and output a difference between the voltages; an output transistor receiving at its base an output voltage of the differential amplifier circuit and outputting from its emitter charging current; a capacitor charged with the charging current to hold the voltage at the output terminal; a bias element generating a voltage substantially equal to the given voltage of the level shift circuit; and a resistance element provided between the bias element and the output terminal for controlling discharging current of the capacitor.

Abstract: A circuit system and process utilizes back electromotive force (BEMF) voltage to assist in safe power down of devices, such as the read/write head in from low factor disk drives or similar devices. The BEMF voltage from a motor device, such as a spindle motor utilized in a circuit using negative voltage to drive some switches, such as positive channel metal oxide semiconductor (“PMOS”) driver transistors, to reduce and/or effectively minimize the on-resistance of the switches while delivering the current from BEMF voltage of the motor to another device, such as a motor that retracts controls a read/write head.

Abstract: A motor drive apparatus 1 having a dynamic braking circuit 5 for producing a deceleration torque utilizing a braking force caused by a synchronous motor 4 acting as a generator when the synchronous motor 4 is deenergized, is equipped with a dynamic braking circuit fault detection capability, and comprises: a DC power supply 2 which is obtained by rectifying input AC power; voltage application means 2, 3, 10, 11 for applying a voltage to the windings of the synchronous motor 4 and to the dynamic braking circuit 5 for a predetermined length of time by switching power transistors A to F connected to the DC power supply 2; current detection means 6 for detecting the value of a current flowing from the power transistors A to F; and fault checking means 11 for checking the dynamic braking circuit 5 for the presence or absence of a fault, based on the current value detected by the current detection means 6 and on a predefined threshold value.

Abstract: A motor control is provided with both open loop and closed loop controllers. The open loop and closed loop controllers provide commutation signals back to gate drives for an inverter, wherein the commutation signals utilize sinusoidal signals in open loop control, and utilize six step commutation in closed loop control.

Abstract: A motor drive circuit comprising: a first transistor and a second transistor connected in series, a voltage of a connection point between the first transistor and the second transistor being a drive voltage applied to one end of a motor coil; an operational amplifier configured to control the first transistor and the second transistor such that the drive voltage is a voltage according to a difference between a first control voltage and a second control voltage for controlling driving of the motor coil; a switch circuit configured to drive the first transistor and the second transistor such that the motor coil is in a state of not being driven regardless of control by the operational amplifier when a pulse signal for intermittently driving the motor coil is at one logic level, and drive the first transistor and the second transistor based on the control by the operational amplifier when the pulse signal is at the other logic level; and an auxiliary drive circuit configured to drive the first transistor and the

Abstract: A method capable of controlling brushless DC motor detects the magnetic pole positions of the rotor with a Hall component to produce a Hall signal correspondingly, generates a PWM signal based on an external control signal with a PWM generator, controls a switch circuit based on the PWM signal and the Hall signal with a driver such that switched output is capable of being sent to the current phase of the stator coils for rotating the rotor. Further, while the Hall signal is detected to be level-switched, the external control signal level increases or decreases corresponding to change of the level of the Hall signal with respect to the duty cycle of the PWM signal being controlled to increase to the preset duty cycle from 0 or to decrease to 0 from the preset duty cycle for eliminating both sharp wave in the current during switching and noise.

Abstract: A controller for an automatic transfer switch mechanism in an electrical distribution panel, which automatically determines motor phase by monitoring the back EMF voltage of the motor when no power is applied to the motor as defined by a pulse width modulation circuit. Phase comparisons of the voltage on the line and load sides of the transfer switch mechanism determine the position of the transfer switch mechanism.

Abstract: A semiconductor integrated circuit capable of reducing the influence of the difference in ambient temperature etc. and realizing a stable phase adjustment circuit has been disclosed. The semiconductor integrated circuit comprises a delay time adjustment circuit for delaying the rising edge or the falling edge of an input signal and changing the amount of delay, a comparison circuit for comparing an output signal from the delay time adjustment circuit with a predetermined voltage, a high-level shift circuit for shifting an output signal from the comparison circuit into a signal on the basis of an output reference voltage, and an output amplifier circuit for amplifying an output signal from the high-level shift circuit and outputting a signal for driving the semiconductor device, wherein the delay time adjustment circuit, the comparison circuit, the high-level shift circuit, and the output amplifier circuit are formed on a single chip.

Abstract: An object of the present invention is to provide a motor driving device capable of outputting an accurate rotation signal while preventing a false detection of B-EMF in a position detecting comparator. The motor driving device includes an output circuit, filter circuit, comparison circuit, current zero ampere detecting circuit, position detecting circuit, sensorless drive arithmetic operation circuit, noise reduction current waveform generating circuit, signal synthesizing circuit, and output transistor control circuit, the comparison circuit including a comparator, polarity switching portion connected to a +terminal and ?terminal of the comparator and signal switching portion, the comparator being structured to be able to set and release an offset having a predetermined voltage value set preliminarily.

Abstract: A motor drive device, for driving an electric motor having a bearing for rotatably supporting an output shaft, has a drive circuit which drives the motor when a voltage level at a signal input terminal of the drive circuit becomes greater than a threshold value. The voltage level at the signal input terminal becomes greater than the threshold value for a certain period when a power switch is turned on or off.

Abstract: A motor drive unit capable of detecting the position of a stationary rotor of any type of sensorless motor, determining a proper startup logic for the rotor, and starting up the motor in a stable condition. To do this, multiple stator coils of the sensorless motor are supplied with rotor-position detecting drive voltages that are adapted to vary the middle point voltage of the multiple stator coils but do not rotate the motor. The middle point voltage of the stator coils is compared with a detection reference voltage. When the result of the comparison matches one of predetermined detection logic patterns, a proper startup logic is generated in accordance with the position of the rotor specified by the matching detection logic pattern to start up the motor. Otherwise, the detection reference voltage is changed in level, and a new rotor-position detecting signal is generated to repeat the procedure for detecting the rotor position.

Abstract: A rotor position detecting circuit includes a first position detecting circuit having a low-pass filter that shapes up phase voltage induced in a phase coil and a first comparator that compares the output voltage of the low-pass filter with a threshold level to form a first rotor position signal, and a second position detecting circuit having a second comparator that compares the phase voltage with a threshold voltage and a control unit that digitally processes the output voltage of the second comparator to form a second rotor position signal. The control unit corrects the first rotor position signal by the second rotor position signal to provide a final rotor position signal when the rotation speed of the brushless DC motor is in a measurable range.

Abstract: A PWM signal generation of the present invention includes a counter, a compare register, a comparator comparing a compare value of the compare register with a count value of the counter and outputting an identity signal, a PWM signal generation circuit determining a pulse width of a PWM signal according to the identity signal, and an additional bit setting register storing an additional bit provided to change the pulse width of the PWM signal.

Abstract: A method of tuning a DC brushless motor, wherein measurement of back EMF voltage is used to detect changes in the torque requirements caused by variation in the operating conditions of the DC brushless motor, the method including varying the timing of the driving signals to the motor to compensate for the changes in the torque requirements.

Abstract: A method capable of controlling brushless DC motor detects the magnetic pole positions of the rotor with a Hall component to produce a Hall signal correspondingly, generates a PWM signal based on an external control signal with a PWM generator, controls a switch circuit based on the PWM signal and the Hall signal with a driver such that switched output is capable of being sent to the current phase of the stator coils for rotating the rotor. Further, while the Hall signal is detected to be level-switched, the external control signal level increases or decreases corresponding to change of the level of the Hall signal with respect to the duty cycle of the PWM signal being controlled to increase to the preset duty cycle from 0 or to decrease to 0 from the preset duty cycle for eliminating both sharp wave in the current during switching and noise.

Abstract: A motor drive method which supplies a drive current in a pulse form to a multiphase motor, to drive the motor. The motor drive method includes the steps of: generating a pulse signal having a duty ratio in accordance with torque, alternately repeating an ON time-period and an OFF time-period in accordance with the pulse signal, to supply a drive current in a pulse form to a phase coil currently driving, interpolating back electromotive voltage of the OFF time-period (Toff), using a back electromotive voltage (Vu) of the ON time-period (Ton), with respect to the back electromotive voltage (Vu) occurring in at least one coil of the multiphase motor, to generate an interpolated virtual back electromotive voltage (Vu?), detecting a zero-cross point, by comparing the interpolated virtual back electromotive voltage (Vu?) with a midpoint voltage (Vcom) of the coil, to generate a BEMF detection signal (BEMF_EDGE), and switching a phase to be driven, based on the BEMF signal (BEMF_EDGE).

Abstract: A pulse generation unit generates a PWM signal whose duty ratio changes according to a target torque of a motor. A back electromotive detection circuit compares a back electromotive voltage generated at a coil of the motor with a middle point voltage of the coil, and outputs a back electromotive detection signal that becomes high level at a timing of the zero crossing point. A phase adjustment unit compares phases of the back electromotive detection signal and a reference signal that becomes a predetermined level at a predetermined timing, and adjusts the duty ratio of the PWM signal by feedback so that the phase error becomes a minimum. A frequency adjustment unit adjusts the frequency of the PWM signal such that the frequency of the PWM signal becomes integral multiples of the frequency of the back electromotive detection signal.

Abstract: A motor driving apparatus has a loss-of-synchronism monitoring circuit that monitors the rotation of a rotary machine such as a brushless DC motor to detect a sign of transition to a state of loss of synchronism. When the sign is detected, an energization control circuit temporarily stops driving of the rotary machine to bring it into a free running state, and thereafter carries out control so as to resume driving of the rotary machine. Further, the motor driving apparatus has an inverter and a drive control circuit that controls switching operation of the inverter based on rotation of the rotary machine.

Abstract: A semiconductor integrated circuit for sensorless driving of a brushless motor, has: an induced voltage detecting circuit which includes a comparator for comparing a voltage induced in an exciting coil by a rotation of a rotor of the brushless motor with a midpoint voltage of the rotor of the brushless motor and outputting a detection signal corresponding to a comparison result, and detects a zero cross point where the induced voltage crosses the midpoint voltage; a logic circuit that outputs a control signal for controlling the brushless motor, in response to a command signal for regulating an operation of the brushless motor and an output signal of the comparator; and a power transistor circuit that supplies a driving current to the exciting coil, the power transistor including a first transistor having one end connected to a power supply and the other end connected to the exciting coil and being controlled in response to the control signal, and a second transistor connected between the other end of the fir

Abstract: A circuit for determining a direction of rotation of an electric motor, the motor having asymmetry and/or eccentricity in a profile of back electromotive force as a function of angular position of a rotor with respect to a stator, the circuit receiving a signal representing the BEMF, and use the corresponding asymmetry and/or eccentricity in the signal to derive the direction of rotation. The signal representing the back emf can be generated by a control circuit. The control circuit can have a feedback loop regulator to generate a control signal (TL or TR) to control a current drive circuit (11,12) to control an amplitude of current (iw) in the windings, the feedback loop regulator being arranged to compare the amplitude of the current (iw) in the windings with a reference value (iset), and use the control signal to provide the signal representing the back electromotive force.

Abstract: An electric motor speed controller for use in a bicycle includes a motor to provide a propulsion force to move the bicycle. The actual motor speed and a target motor speed are compared, and if the actual motor speed is lower, more current is supplied to the motor, and if the actual motor speed is higher, less current is supplied to the motor.

Abstract: A method is for estimating an angular position of a rotor of a motor having position sensors along the circumference of a stator and generating digital signals that switch each time the rotor crosses certain angular positions. The method includes storing rotor angular positions at every digital signal switching, and determining for each rotor revolution a time interval elapsed between a current and a precedent switching edge of the signal generated. The method also includes estimating the angular position during a current rotor revolution by identifying which position sensor generated the last detected switching edge. The corresponding angular position and the time interval elapsed between two consecutive rotor crossings, through a same angular position, correspond to a sum between the angular position and a product between a fraction of the time interval elapsed from the corresponding precedent switching edge multiplied by 360° and a number of polar pairs.

Abstract: Disk drive spindle jitter is comprised of electrical noise, error due to pair pole asymmetry, and random disk speed variances. Error caused by pair pole asymmetry can be identified and compensated for by detecting over a single rotation of a rotor a plurality of zero cross signals. These signals can be statistically analyzed over a period of a plurality of revolutions of the rotor so as to identify the systematic error caused by pair poles. Once identified, this pair pole error can be used to modify zero cross signals and/or modify commutation signal driving the disk so as to arrive at a more accurate determination of disk speed and to precisely control the speed of the disk.