Abstract: A synchronous electric motor drive system capable of driving at speeds near zero is provided. An energization mode determination unit switches six energization modes successively based on a terminal potential detected of the de-energized phase of a three-phase synchronous electric motor or on a stator winding wire connection point potential (neutral point potential) detected of the three-phase synchronous transmission unit. A voltage command correction unit corrects by a correction amount ?V an applied voltage command destined for the synchronous electric motor to supply the synchronous electric motor with a repeated waveform of a positive pulse, negative pulse, and zero voltage as a line voltage waveform of the energized phases in each of the six energization modes, the positive pulse voltage being polarized to cause the synchronous electric motor to generate a forward rotation torque, the negative pulse voltage causing the synchronous electric motor to generate a reverse rotation torque.

Abstract: A back electromotive force (EMF) detector for a motor is disclosed. The back EMF detector includes an upper switch, a lower switch, a current sensing resistor and a first to third resistance providers. The upper and lower switches are controlled by a first and a second control signal respectively. The current sensing resistor coupled between the lower switch and a reference ground voltage. A first terminal of the first resistance provider coupled to the upper switch, and a back EMF detection result is generated at a second terminal of the first resistance provider. The second resistance provider coupled between the reference ground voltage and the first resistance provider. The third resistance provider is coupled between the coupled terminal of the first and second resistance provider and the lower switch. Wherein, the first to the third resistance providers are determined by at least one characteristic parameter of the motor.

Abstract: There are provided a motor driving apparatus and method, the motor driving apparatus including a current detecting unit detecting a level of a driving current applied to a motor for each predetermined period, a current comparing unit comparing the level of the driving current detected by the current detecting unit in a previous period and the level of the driving current detected by the current detecting unit in a current period, and a controlling unit adjusting a level of a reference signal compared with a back electro motive force (BEMF) signal of the motor based on an output of the current comparing unit.

Abstract: Provided is a motor position detecting unit that includes a first computing element configured to output three-phase back-electromotive foreces (back-EMFs) based on a linear computation; a second computing element configured to output three-phase back-EMF based on a non-linear computation; and a computing controller configured to receive a control signal, three-phase voltage and current, and selecting any one of the first and second computing elements based on the received control signal, the received three-phase voltages and currents, wherein the control signal includes information on operation modes of an external motor.

Abstract: A motor driving module is provided which includes a motor driving unit configured to control a PWM inverter on the basis of positional information and a control signal; a PWM inverter configured to output three-phase voltages on the basis of DC power according to control of the motor driving unit; a phase voltage estimating unit configured to output three-phase estimated voltages on the basis of the positional information, the DC power, and a voltage modulation index; and a position detecting unit configured to output the positional information on the basis of the three-phase estimated voltages, wherein the positional information is on an external motor that operates on the basis of the three-phase voltages.

Abstract: A method for determining the rotor angle of a synchronous machine. In one implementation, the method includes generating a multiplicity of pulse-width-modulated drive signals for the phases of an inverter feeding the synchronous machine depending on a voltage to be fed into the synchronous machine, changing the pulse width modulation frequency of at least one drive signal of the multiplicity of pulse-width-modulated drive signals, with the result that the duration of the switching states of the inverter in which an active voltage phasor is output is extended in order to generate a switching pattern for the phases of the inverter, driving the inverter with the generated switching pattern, determining one or more of neutral point potentials at the neutral point of the synchronous machine during driving of the inverter with the switching pattern, and calculating the rotor angle of the synchronous machine depending on the determined neutral point potentials.

Abstract: Determining the rotor angle of a synchronous machine. In one aspect, the invention provides a method that includes generating a multiplicity of pulse-width-modulated drive signals for the phases of an inverter feeding the synchronous machine depending on a voltage to be fed into the synchronous machine, and applying a first phase shift to one or more of the multiplicity of pulse-width-modulated drive signals, so that the duration of the switching states of the inverter is extended in order to generate a first switching pattern for the phases of the inverter. The method also includes applying a second phase shift to one or more of the multiplicity of pulse-width-modulated drive signals for generating a second switching pattern, selecting one or more of the first and second switching patterns, determining one or more of neutral point potentials at the neutral point of the synchronous machine, and calculating the rotor angle of the synchronous machine.

Abstract: A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage, and exciting a winding of the motor with the rectified voltage. The winding is excited in advance of predetermined rotor positions by an advance period that is updated in response to a zero-crossing in the alternating voltage. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

Abstract: There are provided a motor driving apparatus and method, the motor driving apparatus including: a filter controlling unit detecting a frequency of a pulse width modulation (PWM) signal and generating a control signal; a first filtering unit filtering a back electromotive force (BEMF) signal according to the control signal; a second filtering unit filtering a reference signal according to the control signal; and a comparing unit comparing output of the first and second filtering units and generating a motor rotor detection signal.

Abstract: A first input of a differential circuit is coupled to a coil tap for a first phase of a multi-phase brushless DC motor. The first phase is associated with an electrically floating coil. A second input of the differential circuit is coupled to a virtual center tap. A divider circuit is coupled between coil taps for other phases of the multi-phase brushless DC motor to define a virtual center tap. The other phases are phases actuated for motor operation when the first phase is electrically floating. The coil tap for the first phase is electrically isolated from the virtual center tap. The differential circuit performs a comparison of the voltage at the coil tap for the first phase to the voltage at the virtual center tap to generate a back EMF signal.

Abstract: In a drive control circuit of a linear vibration motor, the drive signal generating unit generates a drive signal whose phase is opposite to that of the drive signal generated during the motor running, after the running of the linear vibration motor has terminated; this drive signal of opposite phase includes a high impedance period during which the driver unit is controlled to a high impedance state. An induced voltage detector detects an induced voltage occurring in the coil. A comparator has a function as a hysteresis comparator in which the output level does not vary in a predetermined dead band, and the comparator outputs a high-level signal or a low-level signal during the high impedance period. When an in-phase signal is consecutively outputted from the comparator during the consecutive high-impedance periods, the drive signal generating unit determines that the linear vibration motor has come to a stop.

Abstract: In a drive control circuit of a linear vibration motor, a drive signal generating unit generates a drive signal used to alternately deliver a positive current and a negative current to a coil. A driver unit generates a drive current in response to the drive signal generated by the drive signal generating unit and supplies the drive current to the coil. An induced voltage detector detects an induced voltage occurring in the coil. After a running of the linear vibration motor has terminated, the drive signal generating unit generates a drive signal whose phase is opposite to that of the drive signal generated during the motor running; this drive signal of opposite phase includes a high impedance period during which the driver unit is controlled to a high impedance state. The induced voltage detector detects the induced voltage occurring in the coil during the high impedance period.

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: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: Sensorless brushless motor control device, comprising: a first amplification module common to the motor phases and laid out for generating an intermediary voltage signal, a voltage divider between each motor phase and a node on which the intermediary voltage signal is generated, wherein each voltage divider is laid out for generating a first corrected electromotive force having a predetermined average value, wherein the computation unit is laid out for controlling the motor on the basis of these first corrected electromotive forces. By using hardware means, this control device enables the average of the corrected electromotive forces to be maintained at the center of the analog acquisition zone of the computation unit.

Abstract: The present invention relates to a drive apparatus and drive method for switching an energization mode when a voltage of a non-energized phase of a brushless motor crosses a threshold. In threshold learning, first, the brushless motor is stopped at an initial position. The brushless motor is then rotated by performing phase energization based on the energization mode from the stopped state. The voltage of the non-energized phase at an angular position of switching the energization mode is detected from a maximum value or a minimum value of the voltage of the non-energized phase during the rotation, and the threshold is learned based on the detected voltage. Alternatively, the brushless motor is positioned at the angular position of switching the energization mode by maintaining one energization mode, and then the energization mode is switched to the next energization mode.

Abstract: A digital signal processor (DSP) is operable to receive a single-phase back electromotive force signal (back-EMF) fed back from a motor and control an inverter for driving the motor based on the single-phase back-EMF signal. The DSP includes an electrical angle building module, a rotation speed control module, and a pulse width modulation control module. In addition, the DSP further includes a field-weakening compensation module. The field-weakening compensation module is operable to automatically regulate an electrical angle based on a rotation speed of the motor and a set of predetermined compensation parameters so that the DSP can be operable to achieve an adaptive control. Furthermore, a motor control system and method are disclosed herein.

Abstract: Disclosed is a current source inverter device which controls the power factor in an arbitrarily configurable manner without a magnetic pole position detector. The device is provided with a current source inverter; a motor supplied with alternating current power from the current source inverter; and a control means which detects the terminal voltage of the motor, calculates the motor's internal induced voltage and the motor current that flows in the motor based on the detected terminal voltage, and controls the current source inverter. The control means calculates the phase difference (?c) between the terminal voltage and the motor current, the phase difference (?x) between the motor current and the internal induced voltage, and the phase difference (?v) between the terminal voltage and the internal induced voltage.

Abstract: A drive signal generating unit generates a drive signal used to alternately deliver a positive current and a negative current to a coil. A driver unit generates the drive current in response to the drive signal generated by the drive signal generating unit and supplies the drive current to the coil. After the drive termination of a linear vibration motor, the drive signal generating unit generates a drive signal whose phase is opposite to the phase of the drive signal generated during the motor running. The driver unit quickens the stop of the linear vibration motor by supplying to the coil the drive current of opposite phase according to the drive signal of opposite phase.

Abstract: The brushless motor driver includes a sample and hold circuit which samples and holds a first value of the first comparison signal in a first case in which a current is forced to flow from a first phase coil of the three-phase brushless motor to a second phase coil and no current is forced to flow to a third phase coil in a first period having a preset setting time and a second value of the first comparison signal in a second case in which a current is forced to flow from the second phase coil to the first phase coil and no current is forced to flow to the third phase coil in a second period having the preset setting time subsequent to the first period. The brushless motor driver includes an addition circuit which adds up the first value and the second value sampled and held by the sample and hold circuit and outputs an addition signal depending upon a result of the addition.

Abstract: A driving circuit for a single-phase-brushless motor includes a driving-signal-generating circuit to generate a driving signal for supplying, to a driving coil of the single-phase-brushless motor, first- and second-driving currents alternately with a de-energized period therebetween, an output circuit, and a zero-cross-detecting circuit.

Abstract: To achieve peak acoustic and power performance, the coil or applied current should be in phase or substantially aligned with the back electromotive force (back-EMF) voltage. However, there are generally phase differences between the applied current and back-EMF voltage that are induced by the impedance of the brushless DC motor (which can vary based on conditions, such as temperature and motor speed). Traditionally, compensation for these phase differences was provided manually and on an as-needed basis. Here, however, a system and method are provided that automatically perform a commutation advance by incrementally adjusting a drive signal over successive commutation cycles when the applied current and back-EMF voltage are misaligned.

Abstract: A vehicle having a traction battery and at least one electric machine for propelling the vehicle is provided. A high voltage DC bus electrically connects the traction battery to the electric machine. A controller monitors and commands power flow through the DC bus, the electric machine, and the battery. In response to a key-off event, the controller immediately discharges the DC bus by providing a current to the electric machines. This discharge continues until the voltage on the DC bus reaches a threshold. As the speed of the electric machine decreases towards a speed threshold, the voltage in the DC bus is maintained. Once the electric machine speed reduces past the threshold, the DC bus discharges the remaining voltage in the DC bus at a rate slower than the first immediate discharge.

Abstract: A method for driving a BLDC motor comprising at least three stator windings, comprising: a) determining a time period, and energizing during the time period two of the windings and leaving a third winding un-energized, based on a first motor state; b) measuring a first voltage representative for the back-EMF generated in the un-energized winding shortly before expiry of the time period; c) applying a commutation at expiry of the current time period; d) measuring a second voltage shortly after the commutation, and calculating a subsequent time period; e) repeating steps b) and c). An electrical circuit and a controller are provided for performing these methods.

Abstract: Problems to be Solved To provide is a motor control device capable of detecting a rotor position of a synchronous motor under a certain accuracy and a low processing load. Means for Solving the Problems The motor control device detects the rotor position ?m by directly finding a rotor position ?m from a rotor position expression (?m=?i???90°) containing, as a variable, a current electrical angle ?i from among a phase current peak value Ip and a phase current electrical angle ?i detected in a phase current peak value and electrical angle detection unit 19 and an induced voltage peak value Ep and an induced voltage electrical angle ?e detected in an induced voltage peak value and electrical angle detection unit 20, and containing, as a variable, a current phase ? capable of being selected using [a phase current peak value Ip] and [an induced voltage electrical angle ?e?a phase current electrical angle ?i] as parameters from a predefined data table.

Abstract: The invention relates to a method and device for determining or checking the plausibility of an offset angle between an assumed orientation and an actual orientation of a rotor (20) relative to a stator (10) in an electric machine (1). In the method, the electric machine is first controlled in a quasi zero-current state, in which substantially no current should flow in the windings of the electric machine. Then a voltage indicator that specifies the direction of a voltage controlled in the electric machine during the quasi zero-current state is determined and subsequently transformed into a coordinate system that is fixed with respect to the rotor. The offset angle or an angle error with respect to a previously assumed, calibrated offset angle can be determined on the basis of the transformed voltage indicator.

Abstract: A management apparatus is described of a rotating motor and a load during power loss; the apparatus comprises a first switching circuit coupled with the rotating motor and a controller of said first switching circuit. The controller is configured to drive the first switching circuit so as to convert a back-electromotive force voltage developed in the rotating motor into a power supply voltage for the load. The first switching circuit is driven in accordance with a first duty cycle. The apparatus comprises a second switching circuit coupled with the load and driven in accordance with a second duty cycle. The controller is configured to vary said first and said second duty cycles to keep the power supply voltage for the load above or equal to a threshold voltage.

Abstract: In an imaging apparatus having a toner container, a method of periodically calibrating a back EMF constant Ke used in a speed control circuit of a DC motor used for driving for a toner metering device. To adjust the value of the back EMF constant Ke, the method uses a plurality of sampled back EMF measurements together with a calculated actual speed of rotation of the toner metering device as measured using motion sensor.

Abstract: A motor controller, operatively connected to a motor having an output shaft, includes a rotary detector to detect a rotation direction and a rotation amount of the output shaft of the motor to generate an actual rotary signal, a drive controller to generate a control signal based on the actual rotary signal and a target rotary signal indicating a target rotary direction and a target rotary amount, and a driver to supply a driving power to the motor based on the control signal. When the motor is in a hold state, the control signal is reversed periodically for a predetermined reverse time period T2 per a predetermined one reverse cycle T1. When the control signal is not reversed for a certain lock detection time period Tr that is longer than the revere cycle T1 of the control signal, supply of the driving power to the motor is blocked.

Abstract: A method of determining when to utilise a back EMF sampling method for motor resistance profiling in at least one DC motor, the method including the steps of analysing a parameter prior to initialising the back EMF sampling method, and upon a determination that the analysed parameter is within a defined range, initialising the back EMF sampling method.

Abstract: An apparatus includes a sensorless field-oriented control (FOC) motor controller. The motor controller includes a pulse width modulation (PWM) controller configured to generate PWM signals and to provide the PWM signals to an inverter. The motor controller also includes an angle sampler configured to receive a commanded voltage angle signal and to provide the commanded voltage angle signal as an output signal in response to a triggering event. The triggering event is based on a voltage or a current associated with an input or an output of the inverter. The motor controller further includes a first combiner configured to combine (i) a feed-forward voltage angle signal and (ii) a second signal based on the output signal. The first combiner is configured to generate the commanded voltage angle signal. In addition, the motor controller includes a second combiner configured to combine a feed-forward voltage amplitude signal and the second signal.

Abstract: A back electromotive force (EMF) detector for a motor is disclosed. The back EMF detector includes an upper switch, a lower switch, a current sensing resistor and a first to third resistance providers. The upper and lower switches are controlled by a first and a second control signal respectively. The current sensing resistor coupled between the lower switch and a reference ground voltage. A first terminal of the first resistance provider coupled to the upper switch, and a back EMF detection result is generated at a second terminal of the first resistance provider. The second resistance provider coupled between the reference ground voltage and the first resistance provider. The third resistance provider is coupled between the coupled terminal of the first and second resistance provider and the lower switch. Wherein, the first to the third resistance providers are determined by at least one characteristic parameter of the motor.

Abstract: An inverter circuit converts electric power supplied to a motor by on/off operations of FETs. A microcomputer controls driving of the motor by controlling the on/off operations of the FETs. The microcomputer operates as a current direction determination part. The microcomputer detects a first potential difference, which is a potential difference between both ends of each diode, and a second potential difference, which is a potential difference between both ends of each diode, when both FETs of each phase are in an off-state. The microcomputer can further determine a direction of current flowing in the motor based on the detected first potential difference and the detected second potential difference.

Abstract: A motor driving apparatus and a refrigerator using the same is provided. The refrigerator may include a compressor, a motor, a driving unit, temperature sensing units sensing the temperatures of storage chambers and an external temperature, and a control unit selecting a driving mode of the driving unit based on the sensing result of the temperature sensing units and controlling the driving unit to drive the motor according to the selected driving mode. In a general operation mode, the control unit controls the driving unit to drive the motor in a 120 degree conduction method, and in a power-saving operation mode, the control unit controls the driving unit to drive the motor in a 90 degree conduction method. The refrigerator increases a pulse width of driving current by converting the conduction method of the motor to drive the motor at a low speed during power-saving operation of the refrigerator.

Abstract: Disclosed is a skin washing apparatus using a brushless DC motor, including: a case for the skin washing apparatus; an operation unit installed outside the case, commanding ON/OFF operation and switching operation for forward and reverse rotations in unit of a predetermined angle; power supply installed at one end of an interior of the case; a brushless DC motor installed inside the case to be operated by electric power received from the power supply as to be rotated forwardly and reversely in unit of a predetermined angle; a control unit for outputting an electrical signal for controlling forward and reverse rotations of the brushless electric motor by a predetermined angle in response to a switching signal of the operation unit; and a skin washing brush mounted on a shaft of the brushless electric motor to be rotated forwardly and reversely according to an operation of the brushless electric motor.

Abstract: The invention relates to an electric device (1) comprising an alternating current electric motor (3) and a control inverter (5) for controlling the phase or phases of the motor (3). The motor (3) comprises, on at least one winding of at least one phase (PA, PB, PC), a point (Ma, Mb, Mc) for measuring a voltage relative to a predefined potential (M), the measurement point (Ma, Mb, Mc) being chosen so that it divides the winding into a first (Za1; Zb1; Zc1) and a second (Za2; Zb2; Zc2) portion such that the electromotive forces (ea1, ea2) induced in the two portions are phase-shifted relative to one another and means (11A; 11B; 11C) for measuring the voltage between the measurement point and the predefined potential. The invention also relates to an associated method for measuring electromotive forces.

Abstract: A method of controlling an electric machine that includes sequentially exciting and freewheeling a winding of the electric machine. The winding is excited in advance of zero-crossings of back emf in the winding by an advance angle, and the winding is freewheeled over a freewheel angle. The method then includes varying the advance angle and the freewheel angle in response to changes in the speed of the electric machine. Additionally, a control system for an electric machine, and a product incorporating the control system and electric machine.

Abstract: A control device for an AC rotating machine having a current limiting function of protecting the AC rotating machine and a driving unit such as an inverter from over-current, in which the control device has the reliable current limiting function in driving the AC rotating machine with known or unknown electrical constant. In the control device, a frequency correction value arithmetic unit has an amplification gain computing element for computing an amplification gain based on an electrical constant of the AC rotating machine and an amplifier for computing a frequency correction arithmetic value based on the amplification gain computed by the amplification gain computing element and the current of the AC rotating machine, in which the frequency correction arithmetic value is outputted as a frequency correction value in a predetermined running state of the AC rotating machine.

Abstract: It is an object of the present invention to provide a motor control device that can improve stability of sensorless control of a permanent magnetic synchronous motor. Rotor position detecting means (10) includes motor parameter correcting means (30) for correcting a parameter (winding resistance of a coil, a magnetic flux amount of a permanent magnet), which is a machine constant of a motor, in order to eliminate an induced voltage difference between a detected induced voltage peak value and a detected estimated induced voltage peak value and detects the rotor position on the basis of the corrected parameter.

Abstract: Analog control of the pulse width used to control the speed of a voice coil motor may be implemented using a “constant-current-charging-capacitor” configuration where the time needed to charge the capacitor is directly related to how far the actual motor speed is from the target speed. The BEMF voltage, indicative of motor speed, is sampled, and then stored in a storage capacitor, which is allowed to charge/discharge to a target voltage level. The time required to charge/discharge the capacitor to the target voltage is directly proportional to the difference between the BEMF voltage and the target voltage, and may be used directly as the pulse width (i.e., the charging time) in the PWM velocity control system. To avoid larger capacitors, a pulse multiplier circuit can be added, allowing charging/discharging the sampled voltage to the target voltage to be repeated by a number, N, of times.

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: An amount of a motor drive current is controlled to an appropriate value. Two coils are provided, and a rotor is rotated by the coils by setting different phases for the supplied currents to the two coils. During a phase where one of the coils is in a high-impedance state, an induced voltage generated in the coil is detected. According to the state of the induced voltage, an output control circuit controls the amounts of the motor drive currents supplied to the two coils.

Abstract: A pumping set includes an electric motor, which exhibits a stator, a rotor and a can arranged between the stator and rotor, and at least one impeller linked with the rotor, wherein the electric motor has engine electronics designed for electronically commutating the electric motor, and the electric motor and commutation are configured in such a way that, in a state where the rotor chamber inside the can and/or the impeller is not filled with liquid, the rotor is shut down.

Abstract: A system for monitoring and controlling a brushless motor associable to an electric power source by means of a rectifier. An actuator assembly is operatively associated to the motor and rectifier. The rectifier is arranged to provide a continuous busbar voltage (Vbar) and a continuous reference voltage (Vref) to the actuator assembly. The actuator assembly includes switches (SW1-6) arranged to energize two phases of the motor simultaneously. The system also comprises a voltage observer, operatively associated to the motor and to the actuator assembly, permitting monitoring of an induced voltage in a non-energized phase of the motor. The system includes a control unit associated to the voltage observer. The control unit is arranged to command the opening of a switch of the actuator assembly for a time interval to interrupt the power supply to the motor, when the reading of the induced voltage in the non-energized phase presents a value within a voltage interval (dV).

Abstract: A motor drive and a method in connection with a motor drive including a frequency converter are provided. The motor of the drive is connected to a load, and the motor is controlled with the frequency controller. The method includes the steps of converting changes in electrical quantities of the motor caused by actions affecting the load into observations representing the changes, selecting control symbols on the basis of matching of the sequences of observations with a set of valid patterns, and controlling the converter based on the selected symbols.

Abstract: Sensorless driving of a brushless DC (BLDC) motor includes detecting a zero crossing time from back electromotive force (BEMF) voltage of the BLDC motor. An instantaneous BEMF voltage and an average BEMF voltage are compared to detect the crossover time, which can be used to change the commutation switching sequence. Since the average BEMF voltage differs for odd and even steps of the commutation switching sequence, average BEMF voltages are calculated separately for odd and even sequences and compared to instantaneous BEMF voltages to detect crossover points for the odd and even sequences. The times to commutations for the odd and even sequences are averaged to provide an average time to the next commutation cycle. The average time can be scaled by a reduction factor to reduce the effects of measurement noise.

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: A conventional method used for a startup mode for a brushless direct current (DC) motor employed complementary inductive rise times. Specifically, inductive rise times rise times for a driving state and its complementary state were compared to one another such that when the inductive rise times cross a switching point had been reached. This methodology, however, significantly affects the efficiency of the driving torque and power consumption. Here, however, a derivative of the inductive rise time is employed, which can determine the switching event without the need for a use of a complementary state, improving motor performance.

Abstract: A stepper motor driver system includes: a digital signal controller configured to digitally synthesize synthesized analog voltage signals that will induce a desired velocity of a stepper motor when applied to a pair of stepper motor windings; and voltage amplifiers, communicatively coupled to the digital signal controller, configured to amplify the synthesized analog voltage signals to produce amplified analog voltage signals and to output the amplified analog voltage signals; where the digital signal controller is configured to synthesize the analog voltage signals by affecting at least one of a phase or an amplitude of each of the analog voltage signals as a function of the desired velocity of the stepper motor.

Abstract: The methods and devices provided herein include methods and devices for controlling a permanent magnet motor. In one implementation, a method is provided that allows for the determination of the values of the phase back EMF voltage and of the phase inductances while the phases are powered with a PWM (Pulse Width Modulation) controlled current and/or voltage.