Abstract: In a drive control circuit of a linear vibration motor, a differential amplifier circuit includes an operational amplifier in which an P-channel type transistor is used as a transistor that receives an input voltage, and the differential amplifier circuit detects an induced voltage occurring in a coil. Before the H-bridge circuit is controlled to a high impedance state, a drive signal generating unit turns on a first transistor and a second transistor, and delivers a regenerative current through the coil, the first transistor, the second transistor and the power supply potential.

Abstract: A permanent magnet motor for position sensorless drive operation provides a stator design that exhibits a saliency (machine asymmetric) functionally dependent on rotor position as caused by periodic magnetic saturation of stator structure. This saturation property is caused by rotor zigzag leakage flux from surface permanent magnets. The stator structure may be designed to further saturate from zigzag leakage flux to provide greatest spatial saliency in the quadrature phase for motor position sensorless position estimation. The position, velocity, and shaft torque can be extracted by measuring the phase current from the stator coil of permanent magnet motor.

Abstract: At least one example embodiment discloses a drive system including a motor including a rotor, the motor configured to receive a measured current, a controller configured to generate a voltage command for the motor, a sliding mode observer configured to determine an estimated current for the motor based on the voltage command, determine a difference between the measured current and the estimated current, and determine a switching control vector and an estimator configured to estimate a rotor position based on the switching control vector, the switching control vector being determined based on the difference and adaptive parameters of the sliding mode observer, the controller being further configured to control the motor based at least in part on the estimated rotor position.

Abstract: A power converter for an electric rotating machine is provided which is designed to ensure a desired length of a current flywheel duration in which current is permitted to freewheel from the electric rotating machine even if the power converter is in a transient state or subjected to an unexpected change. The power converter is equipped with a controller and a switching circuit which is disposed between a power supply and windings of the electric rotating machine. The switching circuit has switches grouped into an upper and a lower arm. The controller works to control an off-operation of one of the switches of one of the upper and lower arm so as to produce a desired length of the current flywheel duration following turning off of the one of the switches, thereby minimizing a loss of rectification and avoiding the backflow of current from the power supply to the windings.

Abstract: The present invention provides a simple, robust, and universal position observer for use with sensorless synchronous machines. The observer may be implemented using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model of the synchronous machine. The observer may be used on any type of synchronous machine, including salient or non-salient pole machines such as a permanent magnet, interior permanent magnet, wound rotor, or reluctance synchronous machine. The observer provides low sensitivity to parameter variations and disturbances or transient conditions in the machine. In addition, no knowledge of speed is required as an input to the observer and an estimated position may be calculated using a subset of the machine parameters.

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 surgical motor control device for controlling a surgical drive unit comprises a sensorless electric motor with M motor windings. The motor control device is configured to perform a method for controlling the drive unit. The motor control device be configured to control the drive unit using a multiphase PWM method. An improved method for controlling a surgical drive unit and an improved surgical drive system are also proposed.

Abstract: A method for determining a direction of rotation for an electronically commutated motor (ECM) is described. The motor is configured to rotate a blower and the method comprises rotating the blower using the ECM and determining if the resulting blower rotation is indicative of the desired direction of rotation for the blower.

Abstract: A method of controlling an electric machine that includes exciting a winding of the electric machine in advance of zero-crossings of back emf by a fixed advance time over a range of speeds. Additionally, a control system for an electric machine, and a product incorporating the control system and electric machine.

Abstract: An electric drive (1) comprises: a permanent magnet brushless motor (2), a motor (2) power supply bridge (3), a circuit for controlling the power supply bridge (3) according to rotor position and phase currents (IS); the drive (1) comprises a circuit (6) for detecting the zero crossings of the induced counter electromotive force (ES) in the stator windings to determine the position of the rotor and a circuit (25) for indirectly detecting the amplitudes of the phase currents (IS).

Abstract: An electrical machine for converting electrical energy into mechanical energy and/or mechanical energy into electrical energy, including at least one rotor position sensor device configured to undertake the steps of measuring an electrical signal during a switching cycle in an end region, and comparing the measurement with at least one similar measurement in at least one previous switching cycle to determine if a known rotor position has been reached.

Abstract: An embodiment of a circuit for maintaining voltage at a voltage bus after a power loss in a hard disk drive system. HDD systems may suddenly lose power and specific tasks, such as parking the read/write head and storing state data may be accomplished using a power generated from back EMF of a motor that is still turning. During the power loss sequence, a drive controller may drive a power chipset to regulate the voltage at a voltage bus so as to conserve power as much as possible. In this manner, the drive circuit may regulate the voltage via a drive algorithm to be just above a threshold voltage (typically 4.4 V) while the HDD system is storing state data, but apply other algorithm for other situations, such as parking the read/write head. Various drive algorithms may be tailored to provide a specific sequence of voltage bus regulation techniques suited to specific applications.

Abstract: Disclosed herein is a sensorless-type brushless DC motor, including: a magnet provided in a rotor; and a stator formed by winding a coil on a core stacked with sheets while facing the magnet, wherein the position of the rotor is detected by detecting back electromotive force induced to the coil, the back electromotive force includes a harmonic component 5 times higher than a fundamental wave, and an amplitude ratio of the 5-times harmonic wave to the fundamental wave is set to be 1% or more. Further, the sensorless-type brushless DC motor can prevent a failure in detecting an initial position of the rotor by controlling a waveform of the back electromotive force and minimize an increase of a starting time.

Abstract: The invention relates to a method for decelerating a drive movement of a power tool and to a power tool suitable for carrying out the method, having a drive driven by a motor, an energy supply device for the provision of electrical energy, a controller having a motor controller for activating the motor and an operating-state recognition module which is to detect at least one operating-state variable and, as a function of this, to output a brake signal, the controller being designed to initiate, as a function of the brake signal, a braking procedure in which brake cycles are provided which have a first time segment, in which the motor is short-circuited, and a second time segment in which current is fed to the motor opposite to its original direction of rotation.

Abstract: A motor control device for a stepping motor including at least two phase coils and a rotor is provided. The motor control device includes a control unit which applies a pulse voltage subjected to pulse width modulation, to each of the at least two phase coils, a back electromotive voltage measuring unit which provides a halt period to temporarily halt the application of the pulse voltage to one of the phase coils when a direction of the coil current flowing in the one phase coil is switched, and which measures a back electromotive voltage induced in the one phase coil during the halt period, an out-of-step detecting unit which detects an out-of-step of the stepping motor if the measured back electromotive voltage satisfies a predetermined criterion, and a voltage control unit which sets a voltage for all phase coils other than the one phase coil to a constant voltage during the halt period.

Abstract: An inverter for an electric vehicle includes a speed instruction generating unit, a frequency voltage converting unit, an integrator and a 2-to-3 phase converter. The speed instruction generating unit outputs a speed instruction for changing the rotational frequency of an electric motor based on the on/off of a signal outputted from the accelerator pedal. The frequency voltage converting unit outputs a voltage instruction based on the frequency of the speed instruction. The integrator outputs a rotational angle by performing integration on the frequency of the speed instruction. The 2-to-3 phase converter receives the voltage instruction and the rotational angle and converts the received voltage instruction and rotational angle into three-phase voltage instructions.

Abstract: A coil current detector detects a current component flowing through a coil. A scaling unit scales a drive signal. An induced voltage component extraction unit extracts an induced voltage component by removing the drive signal, scaled by the scaling unit, from the coil current component detected by the current detector. A phase difference detector detects a phase difference between the phase of the drive signal and that of the induced voltage component. A signal adjustment unit adjusts the drive signal so that the phase difference detected by the phase difference detector can be brought close to a target phase difference.

Abstract: Disclosed is a linear electric motor having a fixed primary comprising a stator divided into a number of sections, including a translating secondary having an operative length longer than any two adjacent sections of the stator in the form of a reaction plate, and a connecting means for connecting only those sections of the stator that are at least partially covered by the reaction plate. The position of the reaction plate relative to the stator is determined by monitoring current in the active representative sections. Power is supplied to each stator section individually, with power supplied in a modulated manner to end active stator sections only partially covered by the reaction plate. A measurement of the current to the active representative section is used to control output voltage to all energized stator sections and is used to determine the change in position of the reaction plate.

Abstract: A driving system for a tri-polar electric motor comprises three phase windings. Winding drivers drive each winding with a driving waveform having a non-zero driving phase and intervals wherein the input is equal to zero at the start, middle and end of each driving phase. Using a driving waveform of this type enables monitoring of the back EMF in the winding during each interval when the input is equal to zero. This enables regular monitoring of the zero crossing point of each winding and hence of the position of the rotor. This enables the motor to operate efficiently without generating a torque ripple.

Abstract: According to one illustrative embodiment, a washing machine comprises a motor including a plurality of coils and one or more permanent magnets, an inverter configured to supply current to the plurality of coils and to measure a back electromotive force (BEMF) waveform from the plurality of coils, and an electronic control unit (ECU) configured to (i) integrate the BEMF waveform to generate an integrated BEMF waveform, (ii) determine a magnetic flux of the one or more permanent magnets using an amplitude of the integrated BEMF waveform, and (iii) control the current supplied by the inverter based at least in part upon the determined magnetic flux.

Abstract: In an electric hair cutter and a control method for its motor rotational speed, the electric hair cutter includes a main body, a BLDC (brushless DC) motor, a power source, a detecting unit, an electrical energy adjusting unit and a control module. The main body has a cutting unit. The BLDC motor drives the cutting unit. The detecting unit can detect the counter-electromotive force of the BLDC motor. The control module may receive the counter-electromotive force signals detected by the detecting unit and may control the electrical energy adjusting unit according to the counter-electromotive force signals so as to keep the BLDC motor rotating at a fixed RPM.

Abstract: Method for control of synchronous electrical motors that enables determining the instantaneous motor load angle and rotor speed without using rotor position sensors. The method is realized with solving the set of differential equations that govern the currents in the stator windings of the motor for the time intervals between each two consecutive crossings of the currents in the windings of their set values and deriving relationships between the induced in the windings back-electromotive force voltages and the parameters of the Pulse Width Modulation. The parameters of the Pulse Width Modulation are measured and stored in a memory and based on the derived relationships the values of the back-electromotive force voltages are calculated continuously in time. From the values of the back-electromotive force voltages the motor load angle and rotor speed are calculated and used as feedback signals for the closed-loop control of the motor.

Abstract: If magnitude relations between the output terminal voltage based on a DC negative terminal of the inverter and a threshold voltage that is a fixed value are compared, polarity thereof is changed at a predetermined rotor phase. The magnitude relation, for example, is detected by an inexpensive and simple apparatus such as a level shift circuit and a NOT circuit. The rotor phase of the permanent magnet synchronous motor is inferred on the basis of changes in the magnitude relation and if it is differentiated, a rotation speed is inferred. If the inferred values of the rotor phase and rotation speed are fed back to synchronous operation or vector control, the free-running permanent magnet synchronous motor is restarted.

Abstract: A brushless fan motor control circuit assembly consists of a high-frequency filter circuit, a rectifier circuit, a power factor enhancing circuit, a current-limit and voltage regulation circuit and a brushless fan motor driving circuit. By means of the high-frequency filter circuit to suppress high frequency noises, the power factor enhancing circuit to enhance the power factor and to save power consumption, the current-limit and voltage regulation circuit to limit the current and to achieve overload protection, the brushless fan motor control circuit assembly controls the operation of a motor of an electric accurately and safely, avoiding fan vibration.

Abstract: A method of the Pulse Amplitude Modulation for the Sensorless Brushless motor, which includes a start-up circuit, a phase detect circuit, a phase commutation circuit, a driving circuit, BEMF detection circuit, and frequency detector, utilizes the control signal of the phase commutation circuit to control the driving circuit so as to drive the outer motor coil and detect the control signal for the driving motor driving circuit by a detection circuit. The motor system can be controlled to reduce the discharge speed to avoid the motor driving circuit shutdown and further speed up the start-up time for the next charging period of the motor driving circuit to achieve the effect of low speed rotation and power saving.

Abstract: An electric motor assembly, mud pulser and a method for transmitting data. The electric motor assembly includes an electric motor having a rotor and a stator that includes one or more windings; one or more sensors on the stator and configured to determine an angular position of the rotor; and a motor control circuitry configured to control a commutation of the electric motor based on signals received from the one or more sensors. The motor control circuitry is configured to determine a total angular rotation of the rotor based on a back emf voltage of the one or more windings and independent of the signals from the one or more sensors.

Abstract: A method is provided for controlling power generation. A control circuit is employed to control first and second switches of each of multiple switch groups of a drive circuit so that the first switches are kept in OFF state while the second switches are each switched between ON and OFF states at each given time point. With the second switches of the switch groups alternately switched ON/OFF, electrical power is fed to a circuit system, which includes a power storage device or an application device of loading.

Abstract: A brushless motor driving apparatus that rotates and drives a brushless motor, which has a plurality of coils, by switching energization modes corresponding to phases of the brushless motor, sequentially switches the energization modes based on a non-energized phase voltage and a voltage threshold. Also, the brushless motor driving apparatus regulates an upper threshold for energization amount based on the voltage threshold and a change in the non-energized phase voltage at timing of switching the energization mode.

Abstract: Provided is a regenerative switched reluctance motor driving system which allows a motor to have a reduced size and weight and an increased efficiency as well as improved energy recovery efficiency at the time of regenerative braking without using a neodymium magnet. Based on an angular position of a rotor in the motor, a constant current flip-flop circuit 2 renders two current paths alternately conductive so as to allow a rectangular-wave current having a width of an electrical angle of 180° to alternately flow in two coils in the motor 3, and shifts the timing of rendering the two current paths alternately conductive, between when driving and when braking the motor 3, by a time during which the rotor is rotated by an angle corresponding to an electrical angle of 180°.

Abstract: A control system controls a multiphase rotating machine by a 120° energization process and a PWM process. In the 120° energization process, respective ones of switching elements of a high side arm and switching elements of a low side arm of a power conversion circuit are turned on. In the PWM process, the switching elements of the power conversion circuit turn on/off so that two phases that are connected to the switching elements that are in the on-state are alternately rendered conductive to the high potential side input terminal and the low potential side input terminal of the power conversion circuit.

Abstract: A position sensorless control methodology for an electrical machine is provided. In particular, one aspect provides a method for position sensorless operation of an electrical machine using direct position error computation from stator flux observation results and stator current measurement.

Abstract: A soft switching control circuit for a DC motor is provided. The soft switching control circuit has an absolute value generating circuit, a threshold voltage generating circuit, and a comparing circuit. The absolute value generating circuit outputs an absolute value signal according to a pair of Hall signals from the DC motor. The threshold voltage generating circuit receives a detected state signal and at least an end voltage of a coil of the DC motor for determining a current on the coil at an actual state change time defined by the detected state signal. According to the determination, the threshold voltage generating circuit outputs a threshold voltage with an adjusted voltage level. The comparing circuit compares the absolute value signal and the threshold voltage so as to generate a state change adjusting signal for modifying the actual state change time.

Abstract: A control method for a brushless, three-phase DC motor. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. A pulse-width modulation duty cycle may be adjusted based on the delta zero crossing error. The pulse-width modulation duty cycle may be used to control a rotational velocity of the rotor.

Abstract: A control system for a motor includes an inverter coupled to the motor. The control system further includes a microcontroller coupled to the inverter. The microcontroller includes a processor programmed to measure an input voltage and acquire a back EMF voltage of the motor. The processor is also programmed to control the inverter to regulate the motor voltage based on the input voltage and the back EMF voltage to facilitate controlling the motor.

Abstract: A frequency converter and a method for determining the position of the rotor of an electric machine are provided. The frequency converter includes a load bridge and a control of the load bridge, for supplying electricity between the load bridge and an electric machine connected to the load bridge. The frequency converter includes a determination for at least one electrical parameter of the electric machine, and includes a determination for the position of the rotor of the electric machine. The load bridge is fitted to supply a first alternating electricity excitation signal, which is formed in relation to the electrical angle of the electric machine, to the electric machine. The frequency converter is further fitted to determine the first alternating electricity response signal corresponding to the first alternating electricity excitation signal, and the position of the rotor is determined on the basis of the first alternating electricity response signal.

Abstract: A microcontroller determines the position of the rotor of a brushless, direct-current motor by determining the time of zero crossing of back electromotive force (EMF) emanating from the non-driven phase winding. The zero crossing point is determined by interpolating voltage differentials that are time stamped. Each voltage differential is the difference between the phase voltage of the phase winding and the motor neutral point voltage. The time of zero crossing is determined without using a comparator and without interrupting the processor at each zero crossing point. The processor interpolates the time of zero crossing independently of when the zero crossing point occurs. A hold signal conductor is connected both to a sample and hold circuit and to the load input lead of a time stamp register. The microcontroller simultaneously captures a phase voltage in the sample and hold circuit and a timer count in the time stamp register.

Abstract: Method for control of synchronous electrical motors that enables determining the instantaneous motor load angle and rotor speed without using rotor position sensors. The method is realized with solving the set of differential equations that govern the currents in the stator windings of the motor for the time intervals between each two consecutive crossings of the currents in the windings of their set values and deriving relationships between the induced in the windings back-electromotive force voltages and the parameters of the Pulse Width Modulation. The parameters of the Pulse Width Modulation are measured and stored in a memory and based on the derived relationships the values of the back-electromotive force voltages are calculated continuously in time. From the values of the back-electromotive force voltages the motor load angle and rotor speed are calculated and used as feedback signals for the closed-loop control of the motor.

Abstract: An anti-noise method for the Direct Current Brushless motor System, which includes a startup circuit, phase detective circuit, motor phase commutation circuit, driving circuit, BEMF detective circuit, and frequency detector, utilizes the BEMF detective circuit to detect the BEMF induced from the coils of the outer motor, and utilizes the sampled voltage phase to determine rotation speed and phase of the external motor by the phase detection circuit and frequency detector. Further, the sampling voltage of the BEMF detection circuit is feedback controlled by the frequency detector, utilized to keep good BEMF to noise ratio, and avoids the BEMF sampling error from the system.

Abstract: Methods and systems for controlling an electric motor are provided. A signal comprising at least first and second cycles is provided to the electric motor. A first flux value for the electric motor associated with the first cycle of the signal is calculated. A second flux value for the electric motor associated with the second cycle of the signal is calculated based on the first flux value.

Abstract: A method for determining the position of a rotor in a permanent magnet synchronous motor includes applying voltage pulses to the windings at successive electrical angles while the motor is at a standstill. The resultant current is sampled. The position of a maximum current is determined by identifying an segment of an electrical cycles which includes the maximum current, and using a spline interpolation to model the current flow in this segment. The maximum current is then correlated to the position of the rotor.

Abstract: A sensorless permanent magnet motor system that prevents negative torque caused by back EMF. The system determines the position of the rotating permanent magnet by monitoring back EMF generated on an inactive coil of the motor system. A snubber circuit is used to prevent the back EMF from causing negative torque on the motor. The voltage of back EMF used to power a logic circuit, such as a microcontroller, that controls the operation of the motor. The microcontroller controls the operation of the motor by detecting back EMF and is also partially powered by the back EMF.

Abstract: A DC-motor (46) actuates a highly-reduced reduction gear of an actuating drive for a flap or valve in order to regulate a gas or liquid volume flow, particularly for heating/ventilation/climatization, or fire or room protection. Current flow in the stator coils (A, B, C) is commutated in a program-controlled manner without integrated position sensors. Algorithms enable counting rotations of rotor (54) of the DC-motor (46). Problems related to the principle of motor rotation speed at low rpm are prevented. The DC-motor (46) includes a stator (44) having three stator coils (A, B, C) which extend over 3n stator poles (52), and an annular-shaped permanent magnet rotor (54) having 2m permanent magnet segments with alternating polarity (N, S), a coaxial cup-shaped external rotor (110) and a coaxial drive shaft (108), whereby n and m are whole multiplication factor numbers (1, 2, 3, 4) and are different from each other.

Abstract: The adapting system for a resonant drive appliance includes a circuit for measuring the back EMF induced in the stator coil of the motor following turn-off of the appliance. The frequency of the back EMF signal is determined from the zero crossings of the EMF signal. The determined frequency is then compared with a running average of previous frequency determinations, and the drive frequency of the appliance is adjusted if the difference between the compared frequencies is greater than a threshold value, e.g. 1 Hz.

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 rotor position detecting apparatus includes a PWM control portion controlling a switching element included in an inverter by a PWM signal having a predetermined frequency, a determination portion determining a magnitude correlation at least two times between a reference voltage specified beforehand and a terminal voltage of each terminal included in a three-phase motor in a state where the terminal voltage corresponds to one cycle of the PWM signal, and a detection portion detecting a position of a rotor of the three-phase motor based on a determination result of the determination portion.

Abstract: An apparatus and a method for detecting a lock error in a sensorless motor are disclosed, where the apparatus includes a multiplexer, a negative booster, a comparator and a timer. The multiplexer can receive a coil voltage from the sensorless motor. The negative booster can receive a neutralizing voltage from the sensorless motor and drop the neutralizing voltage. The comparator can compare the coil voltage with the dropped neutralizing voltage for outputting a zero-crossing signal. The timer can count time duration during the zero-crossing signal maintained at the a logic level and determine the lock error in the sensorless motor when the time duration exceeds a predetermined period.

Abstract: The present invention provides a simple, robust, and universal position observer for use with sensorless synchronous machines. The observer may be implemented using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model of the synchronous machine. The observer may be used on any type of synchronous machine, including salient or non-salient pole machines such as a permanent magnet, interior permanent magnet, wound rotor, or reluctance synchronous machine. The observer provides low sensitivity to parameter variations and disturbances or transient conditions in the machine. In addition, no knowledge of speed is required as an input to the observer and an estimated position may be calculated using a subset of the machine parameters.

Abstract: This invention relates to the control of electrical machines and is concerned more particularly, though not exclusively, with the control of flux switching brushless permanent magnet and switched reluctance electrical machines without a mechanical shaft position sensor. Brushless Reluctance and permanent magnet motors can be used in many applications, since they do not require the use of commutators or brushes in supplying electrical power to the rotor of the motor.

Abstract: A bridge rectifier circuit, which takes control of a current flowing through an armature winding of a motor-generator and a battery, includes rectifier elements each made of a MOSFET; phase current detection means that detect the amount and the direction of current flowing between the drain and the source of the FET; and a control means that takes on/off control of the FET by applying a control voltage between the gate and the source thereof; wherein when the phase current detection means detect a reverse current flowing through the FET exceeding a first predetermined value, the control means applies a control voltage between the gate and the source of the FET so as to turn on the FET.

Abstract: A voice coil motor (VCM) is controlled by applying a bipolar square wave actuator current to the VCM and calibrating a back electromotive force (back-EMF) measurement on the VCM in response to the square wave actuator current. Back-EMF on the VCM is measured while an actuator arm coupled to the VCM is in motion, and the VCM is controlled to move the actuator arm in response to the measured back-EMF voltage.