Abstract: A controller, responsive to a signal indicating deactivation of a vehicle and disconnection of a traction battery from an inverter, generates a d-axis current command for the inverter having a ramp portion that defines a rate of change in current magnitude that depends on an electric angle between a rotor and stator of an electric machine.

Abstract: This application provides a vehicle and a power battery heating apparatus and method thereof. In the method, when a current temperature value of a power battery is lower than a preset temperature value, and a heating condition of the power battery meets a preset condition, a three-phase inverter is controlled to cause a three-phase alternating current motor to generate heat to heat a coolant flowing through the power battery. A preset quadrature-axis current and a corresponding preset direct-axis current are obtained to control the three-phase inverter to adjust a phase current of the three-phase alternating current motor in the heating process, so that electromagnetic torque with a small torque value is outputted at a motor shaft. The electromagnetic torque causes the motor output shaft to output a pre-tightening force to the transmission mechanism, thereby eliminating an engagement gap and effectively avoiding jitters of the vehicle.

Abstract: A motor system with an input for coupling to a motor control signal that, when presented in a predetermined state, indicates a motor receiving power should be disabled from rotating. The system also includes controller circuitry for providing a disabling signal to motor rotation, independent of processor software control signaling and the power, in response to the control signal.

Abstract: A motor control system includes an inverter, a voltage control calculating a voltage command value indicating a voltage to be applied to a motor from the inverter based on a deviation between the current command value and the actual current detection value, and a torque ripple compensation unit adding a compensation value for compensating a torque ripple in the motor to a signal value on an upstream side in a signal flow that passes through the voltage control unit. The torque ripple compensation unit includes a phase compensator calculating a compensation value component in the voltage control unit based on an actual angular velocity value indicating an angular velocity at which the motor rotates, and an inverse characteristic processor calculating a compensation value component for compensating the torque ripple based on an inverse characteristic of an open loop transfer function in a feedback control.

Abstract: A comparator receives a target voltage and a reference voltage at its inverting and non-inverting input terminals, and outputs a signal corresponding to the level relationship between those voltages A node provided on the output side of the comparator is fed with a signal equivalent to the output signal of the comparator. Between the node and the non-inverting input terminal of the comparator, a capacitor is inserted.

Abstract: A variety of methods, controllers and electric machine systems are described for pulse control of electric machines (e.g., electric motors and generators). To improve the energy conversion efficiency of the machine, pulse control involves determining if the machine should operate in a continuous mode or pulse mode, and if the latter, defining a magnitude, duty cycle, and frequency for the pulses. One or more tables, indexing by a wide range of speeds and torque requests, is/are used to define the pulsing frequency or a pulsing frequency pattern.

Abstract: A motor controller is configured to reduce the motor noise. The motor controller is used for driving a motor, where the motor has a motor coil and a rotor. The rotor is divided into four pole regions N1, S1, N2, and S2 to switch phases. The four pole regions have a manufacturing tolerance and the pole region N1 has a time interval T1. The motor controller comprises a switch circuit, a control unit, a phase detecting unit, and a current detecting unit. The switch circuit is configured to supply a driving current to the motor coil. Based on the manufacturing tolerance and the time interval T1, the time point to detect the driving current is set to be a proportional time PT before the phase switching, where PT/T1 is greater than the manufacturing tolerance.

Abstract: A motor driving apparatus and a control method thereof, including a dc-link capacitor configured to store DC power, an inverter including a plurality of switching elements and converting the DC power stored in the dc-link capacitor into AC power to output the power to a motor, a dc-link resistor element disposed between the dc-link capacitor and the inverter; and a controller configured to control an operation of the inverter. The controller calculates a phase difference between a first reference voltage vector among a plurality of reference voltage vectors that are preset on the space vector and a voltage command, generates a switching frequency, determines a first operating point located in a dead band that is a one-phase current undetectable area in one switching cycle and a second operating point located at an outer position including a boundary of the dead band, and controls operation of the plurality of switching elements.

Abstract: A back electromagnetic force detection circuit detects a counter EMF generated in a coil of a stepping motor. A revolution count detection circuit generates a revolution count detection signal. A determining circuit generates a determination signal that is asserted if the revolution count detection signal is stable across multiple consecutive cycles. A current value setting circuit generates a current setting value indicating a target value of a coil current. The current value setting circuit sets the current setting value to a predetermined value in a period in which the determination signal is negated, and adjusts the current setting value according to the counter EMF in a period in which the determination signal is asserted. A constant current chopper circuit generates a pulse modulation signal that modulates by way of having a detection value of a coil current approach close to a target value of the current setting value.

Abstract: A control device for an inverter has a first inverter terminal, a second inverter terminal and a plurality of bridge branches, which bridge branches each comprise a first semiconductor, a winding terminal and a second semiconductor switch. The winding terminals are connected to a winding arrangement. The control device is configured to output a control signal which enables a first bridge branch state and a second bridge branch state in the case of at least two of the bridge branches in a first operating state, wherein, in the first bridge branch state, the second semiconductor switch assigned to the bridge branch is switched on, and wherein, in the second bridge branch state, the second semiconductor switch assigned to the bridge branch is switched off. At least two of the bridge branches are occasionally simultaneously in the first bridge branch state, and a change of said at least two bridge branches into the second bridge branch state is subsequently carried out at different points in time.

Abstract: A motor control device includes at least one power converter. The at least one power converter is connected between a DC power supply and a motor. The at least one power converter converts a DC electric power into a multi-phase AC electric power by operating a plurality of switching elements and supplies the multi-phase AC electric power to the motor. The motor control device calculates a command value for operating the at least one power converter to control electrical conduction to the motor. The motor control device determines an overcurrent fault when a value of a current flowing through the at least one power converter or a motor winding of the motor exceeds an overcurrent threshold value. The motor control device estimates or detects a power supply current that is a direct current flowing between the DC power supply and the at least one power converter.

Abstract: A power conversion device including: a first and second multi-phase inverters (MPI1,MPI2) to receive a DC voltage (Vdc) and convert into AC voltages (Vacs), when fc represents a frequency of a PWM signal output from each of the MPI1 and the MPI2, fr represents a lower limit frequency defined by noise regulation of the power conversion device, an absolute value of a differential voltage being a difference between: a first average voltage, which is an average value of first voltage commands of respective phases as command values for the Vacs of MPI1; and a second average voltage, which is an average value of second voltage commands of respective phases as command values for the Vacs of MPI2, is set equal to or less than k2·fc/fr·Vdc [V] (k2 is an odd number equal to or more than one), to reduce noise in a frequency band defined by noise regulation.

Abstract: A method for driving an electric motor includes providing two controllers for driving the electric motor. The two controllers use different control methods to drive the electric motor. The method further includes selecting a first controller of the controllers as a primary controller to drive the electric motor and a second controller of the controllers as a secondary controller, monitoring a control of the electric motor, and switching the control of the electric motor from the primary controller to the secondary controller if an error condition is detected in the control of the electric motor.

Abstract: The present disclosure provides a driving device with a low cost and/or a simple advance angle control for a motor. A voltage zero crossing detecting unit 314 is configured to detect an induced voltage generated from a coil with a specific phase of a fan motor 202 being zero of a voltage zero crossing point. A detection period setting unit 316 is configured to set at least one detection period synchronously with the voltage zero crossing point. A coil voltage detection comparator 302 is configured to compare a terminal voltage generated from one end of the coil with the specific phase with a threshold voltage, and generate a coil voltage detection signal S3 indicating a comparison result. A current phase detecting unit 318 is configured to generate a phase detection signal S8 indicating a relationship between the coil current flowing through the coil with the specific phase and a phase of an induced voltage based on a level of the coil voltage detection signal S3 in the detection period.

Abstract: An apparatus includes a coarse resolver configured to output coarse position signals indicative of a coarse position of a drive shaft of a motor. The apparatus also includes a fine resolver configured to output fine position signals indicative of a fine position of the drive shaft of the motor. The apparatus further includes a control circuit. The control circuit is configured to receive the coarse position signals from the coarse resolver and the fine position signals from the fine resolver and generate an initial position output, based on the coarse position signals, that indicates an initial position of the drive shaft. The control circuit is further configured to generate a subsequent position output, based on the fine position signals, that indicates a subsequent position of the drive shaft.

Abstract: Provided is a drive control device for an electric motor in which the number of terminals and the number of wires can be reduced. The drive control device includes: an inverter circuit that drives an electric motor having a plurality of phases; a drive circuit including drivers; a control circuit that outputs a control signal to control the drive circuit; and a signal line that connects the control circuit to the drive circuit to transmits a control signal from the control circuit to the drive circuit, in which the number of signal lines is fewer than the number of the phases of the electric motor.

Abstract: A resonant turn-off circuit is provided to disconnect an inadequate power source and transfer a load to an alternate power source. In the circuit, a main switch is turned off before the AC cycle of the power source crosses zero. As a result, the main switch may be turned off quickly to transfer electric power supplied to a load to a second power source. The circuit may include resonant switches, a capacitor, a pre-charging power supply and an inductor. When it is desired to turn off the main switch, a resonant switch is turned off to cause a voltage reversal across the switch.

Abstract: A electric power tool, comprising a control system electrically coupled to a power supply and a motor to supply current to the motor, where the motor may be coupled to a driven element of a tool so as to drive the driven element. The control system may have a continuous power mode and a boost power mode to supply current to the motor at a greater amount than in continuous power mode, and may be configured to switch between the continuous power mode and the boost power mode based upon a sensed load on the electric motor. In some embodiments, the control system may switch to a cutback power mode to supply current to the motor at a lower amount than in continuous power mode is the load does not decrease before a predetermined time elapses.

Abstract: An AC excitation synchronous rotating electric machine includes a multi-phase coil, an armature core, an outer yoke core, a field-winding-less rotor and a controller. The armature core has the multi-phase coil wound thereon. The rotor is rotatably disposed so as to face the armature core and includes magnetic poles each having a facing portion and a magnetic reluctance portion. The facing portion is provided at one axial end of the magnetic pole so as to face the outer yoke core and allow magnetic flux to flow therebetween. The magnetic reluctance portion is provided at the other axial end of the magnetic pole to impede the magnetic flux from flowing therethrough. The controller controls supply of multi-phase alternating current to the multi-phase coil so that magnetomotive force generated in the armature core is applied to the magnetic poles, thereby causing the magnetic poles to operate as a DC field.

Abstract: An actuator of a camera module includes a magnetic body, a driving coil disposed to face the magnetic body, and a driving apparatus including a driving circuit connected to the driving coil and selectively providing one of a first control signal and a second control signal to the driving circuit according to a driving mode. The driving apparatus compares a level of a control signal of a previous driving mode with a level of a control signal of a following driving mode upon the driving mode being switched.

Abstract: The present invention provides an acceleration method for V/f controlled induction motor in flux-weakening region, which comprises: acquiring no-load magnetizing current Im of the induction motor at current stator frequency; selecting a smaller one of 0.5·Im(1/?+1) and (Im2+?)/(Im+?Im) as magnetizing current set point, in which ? is an estimated total leakage inductance coefficient; getting an error signal by subtracting the magnetizing current of the induction motor from the magnetizing current set point; determining the stator frequency for the next control period according to the error signal which is provided as a controlling variable of negative feedback. The acceleration method of the present invention can provide the maximum output torque in flux-weakening region and has a larger tolerance for the error of the estimated leakage inductance.

Abstract: A load drive apparatus includes: a first drive element that drives a first load; a second drive element that drives a second load; a control circuit that controls the first drive element and the second drive element; a power supply circuit that supplies electric power; and a failsafe circuit that includes an abnormality detection portion detecting whether an abnormality occurs in at least one of the control circuit and the power supply circuit, the failsafe circuit controlling the first drive element and the second drive element to drive the first load and the second load when the abnormality detection portion has detected that an abnormality occurs in at least one of the control circuit and the power supply circuit and also when the load drive apparatus receives at least one of a command directing a drive of the first load and a command directing a drive of the second load.

Abstract: A power supply generates power factor corrected power from AC power having one or more phases and different levels of output voltages. The power supply includes a power factor correction circuit that charges a capacitor through at least one inductor. Each inductor of the at least one inductor is independently connected to the capacitor to charge the capacitor with rectified power.

Abstract: A surge according to a change of a switching state can be reduced without increasing a torque ripple of a motor. A first switching signal to control switching of a boost converter is generated on the basis of a comparison of a first duty command value and a first triangular wave carrier of the boost converter. A second switching signal to control switching of an inverter is generated on the basis of a comparison of a second duty command value and a second triangular wave carrier of the inverter. In addition, the second triangular wave carrier is generated such that a frequency of the second triangular wave carrier becomes equal to a frequency of the first triangular wave carrier and a phase of the second triangular wave carrier is different from a phase of the first triangular wave carrier by 180 degrees.

Abstract: Described embodiments provide circuits, systems and methods for controlling operation of brushless direct current motors that include a plurality of windings. A gate driver provides control signals to switching elements that control a voltage applied to each of the windings of the motor. A zero crossing detector detects zero crossings of a voltage applied to the windings and transitions a zero crossing signal between a first logic level and a second logic level based on the detected zero crossings. A position estimator estimates an angular position of the motor, and counts in a first direction based on the first logic level of the zero crossing signal, and in a second direction based on the second logic level of the zero crossing signal. An observer determines a value of the counter after an elapsed time, and generates an angular position signal based upon the value of the counter.

Abstract: A motor control apparatus that calculates duty command values of respective phases for controlling currents of a motor by means of a control calculation, forms PWM-signals in correspondence to the duty command values, drives the motor by means of an inverter based on the PWM-signals, and which is provided a rotation sensor to detect a motor angle of the motor.

Abstract: An electrical controller for electric rotating machines is provided. A control system for electric rotating machines transmits a controlled quantity of current to or from different windings of the electric rotating machine at any given time. Furthermore, the amplitude of the current is independently variable of the timing and duration of the transmission of the current to or from the windings. This allows increased control of the electric rotating machine and facilitates the operation of the electric motor at high mechanical and/or electrical speeds.

Abstract: A flyback control mode-based controller includes a power supply circuit, a position-checking circuit, a current-checking circuit, a control circuit, and a power output circuit. The power output circuit includes a controlled energy conversion unit. The energy conversion unit includes a control switch and an energy conversion circuit. The energy conversion circuit uses the capacitor C circuit, the inductor L circuit, or the LC circuit to connect parallelly or serially with an inductor in a motor winding L so as to form an oscillation circuit, such that periodic oscillations with attenuation are enabled by relying on the energy stored in the motor winding L. By applying the controller to motors having forward control mode or motors having flyback control mode, the current to be released by the motor during discharging can be repeated used, thereby achieving maximum energy conservation.

Abstract: A driving method for a spindle motor and associated driving system and apparatus are provided. The driving method includes the following steps. Plural modulation signals and plural floating phases corresponding to the plural modulation signals are adjusted. A floating period comes immediately after an active period of each of the plural modulation signals according to the plural floating phases. During the floating period, a demagnetization time of the spindle motor is acquired according to a first terminal voltage signal at a first terminal of the spindle motor. If the demagnetization time is not smaller than the threshold time period, the step of adjusting the plural modulation signals is repeatedly done. Whereas, if the demagnetization time is smaller than the threshold time period, after the demagnetization time, a phase of the spindle motor is obtained according to the first terminal voltage signal.

Abstract: Systems and methods to eliminate current surge during spindle spin up, include, in at least one aspect, a method including: using a duty cycle with a spindle motor to spin-up the spindle motor to achieve a steady-state operating speed for the spindle motor, wherein the spindle motor comprises phase windings; and using an adjusted version of the duty cycle for a period during the spin-up to reduce current surge onto a supply capacitor associated with the spindle motor during phase switching for the phase windings.

Abstract: Provided is an inverter apparatus capable of preventing occurrence of overcurrent in an AC motor and stably controlling driving of the AC motor. The inverter apparatus controlling the AC motor included in an electric compressor includes a shunt resistor for detecting current flowing in the AC motor, and a limit value control unit controlling a current limit value for a detected current detected at the shunt resistor. The limit value control unit determines whether the number of times the detected current becomes equal to or more than the first threshold within a first predetermined time is equal to or more than a first number of times. The limit value control unit decreases the current limit value when the number of times the detected current becomes equal to or more than the first threshold within the first predetermined time is equal to or more than the first number of times.

Abstract: A data storage device is disclosed comprising a spindle motor configured to rotate a disk, wherein the spindle motor comprises a stator, a rotor, and a plurality of windings. The data storage device further comprises an isolation circuit configured to isolate the windings from a supply voltage, a head actuated over the disk, and control circuitry comprising a spindle motor driver comprising a plurality of switches including a first switch and a second switch configured to commutate the windings. While driving the isolation circuit with a first calibration current, the first switch is driven with a second calibration current and a first current flowing through the first switch is measured. While driving the isolation circuit with the first calibration current, the second switch is driven with the second calibration current and a second current flowing through the second switch is measured.

Abstract: A method for controlling a permanently excited synchronous motor, in particular a brushless direct-current motor, having a permanently magnetized rotor and a number of stationary Stator windings to which an alternating voltage of predetermined amplitude and frequency is applied, wherein the frequency of the alternating voltage is determined by the speed of the motor and a phase difference results between the alternating voltage and the alternating current for each Stator winding. Accordingly, current is applied to the Stator windings in such a way that between alternating voltage (UPhase) and alternating current (IPhase) arises a phase angle (?Target, ??Target), which is selected according to speed (?), motor inductance (L), and the power received by the motor.

Abstract: A motor control system is provided, and includes a motor, at least one differential amplifier configured to monitor phase current applied to the motor, and a current compensation controller. The current compensation controller is in communication with the at least one differential amplifier, and is configured to periodically determine a common-mode voltage of the at least one differential amplifier. The current compensation controller is also configured to determine a corrected phase current value based on the common mode voltage.

Abstract: Provided is a motor control apparatus that can easily distinguish between a current sensor abnormality and a rotation-angle sensor abnormality, without making a current sensor a duplex system. An MGECU estimates a W-phase current on the basis of a V-phase current detected by a current sensor, and estimates the V-phase current on the basis of a detected W-phase current. An actual torque of a motor generator is estimated on the basis of the detected V-phase current and the estimated W-phase current, and the actual torque of the motor generator is also estimated on the basis of the detected W-phase current and the estimated V-phase current. Then, an evaluation is made whether an abnormality is an abnormality of the current sensor or an abnormality of a resolver, on the basis of the differences between the torque command value for the motor generator and both the estimated actual torques.

Abstract: According to a control apparatus for an AC motor, a switching section selects a two-phase control current value as a current fixing value, when a first current detection value of a first phase of the AC motor and a second current detection value of a second phase of the AC motor are normal. The switching section selects an one-phase control current value, which is calculated based on a normal phase current detection value, which is a value of a normal phase and is one of the first and second current detection values, as the current fixing value, when an abnormality is detected in part of the first and second current detection values, and a predetermined period has elapsed from the detection of the abnormality.

Abstract: According to a control apparatus for an AC motor, a switching section selects a two-phase control current value as a current fixing value, when a first current detection value of a first phase of the AC motor and a second current detection value of a second phase of the AC motor are normal. The switching section selects an one-phase control current value, which is calculated based on a normal phase current detection value, which is a value of the normal phase and is one of the first and the second current detection values, as the current fixing value, when it is determined that the current supplied to the AC motor has been stabilized after an abnormality is detected in part of the first and second detection values.

Abstract: Power converters and methods are presented for driving an AC load connected through an intervening filter circuit, in which at least one filter current or voltage signal or value is determined according to feedback signals or values representing an output parameter at an AC output of the power converter, and AC electrical output power is generated at the AC output based at least partially on the at least one filter current or voltage signal or value.

Abstract: The invention provides a drive control device that comprises: inverters that are connected to a motor; a variable resistive element that is connected between the motor and each of the inverters; a current/voltage detection device connected between the motor and each of the inverters; and a controller that, when detecting a fault of an inverter that drives the motor based on a detection signal from the current/voltage detection device, gradually increases a resistance value of a variable resistive element provided between the faulty inverter and the motor at a velocity of a resistance variation such that a surge voltage has a voltage value for which the variable resistive element and the motor are not damaged, and executes drive control of the motor by a normal inverter other than the faulty inverter.

Abstract: Disclosed herein is an apparatus for driving a motor, the apparatus including: an inverter applying a direct current voltage to each phase of a brushless direct current (BLDC) motor by a switching operation; a reference voltage generating unit generating at least one reference voltage using a voltage of a neutral point of the BLDC motor; and a motor driver detecting a zero cross point (ZCP) of back electromotive force of each phase by comparing a phase voltage of each phase of the BLDC motor with the reference voltage and generating a PWM signal for controlling the switching operation of the inverter and a phase switching of each phase using information of a position of the zero cross point (ZCP).

Abstract: Disclosed is an inverter control system and method for an eco-friendly vehicle, by which overall improvements can be obtained in terms of switching loss, electromagnetic performance, noise-vibration-harshness (NVH) performance, control stability, and so forth, when compared to a conventional case in which one fixed switching frequency and one fixed sampling frequency are used over the entire operation area. To this end, the inverter control method for an eco-friendly vehicle which generates a pulse width modulation (PWM) signal according to a switching frequency and a sampling frequency and controls ON/OFF driving of a switching element, in which a controller changes and sets the switching frequency according to a current motor speed, changes and sets a sampling frequency according to the switching frequency, and controls on/off driving of a switching element according to the switching frequency corresponding to the motor speed and the sampling frequency.

Abstract: A motor controlling apparatus includes: a controller configured to (i) compute a target duty cycle value which is a target value for a duty cycle used for a pulse width modulation control for controlling a motor, and (ii) specify 100% as a duty cycle specified value when the target duty cycle value is greater than an upper limit value which is below 100%, or specify 0% as the duty cycle specified value when the target duty cycle value is less than a lower limit value which exceeds 0%; and a control signal generator that generates a control signal for controlling the motor at the duty cycle specified value specified by the controller.

Abstract: In a method and control system for controlling a brushless, electronically commutated electric motor (M), a three-phase source AC voltage (UN) is rectified and fed to a DC link voltage (UZK), which is supplied to an inverter (2) via a slim DC link circuit (6). A motor control unit (10) for PWM pulsing controls the inverter for commutating the electric motor (M) and adjusting the motor speed with a variable duty cycle (A). The duty cycle (A) is influenced by a compensating factor (k) such that the product of the DC link voltage (UZK) and a resulting DC link current (IZK) is kept constant in the link circuit (6). The DC link voltage (UZK) is monitored. When a first threshold value (UZKac.max1) of an AC component (UZKac) is exceeded, the compensating factor (k) is modified to lower the current AC component (UZKac) below the threshold value (UZKac.max1).

Abstract: An inverter for a permanent magnet brushless dc machine, having a permanent magnet rotor and a set of stator windings, applies the full dc voltage provided to the inverter to each phase of the machine.

Abstract: In a driver, a discharging module discharges, at a discharging rate, the on-off control terminal of a switching element in response to a drive signal being shifted from an on state to an off state. A changing module determines whether a condition including a level of a sense signal being higher than a threshold level during the on state of the drive signal is met, and changes the discharging rate of the on-off control terminal in response to the drive signal being shifted from the off state to the on state upon determination that the condition is met. A loosening module loosens the condition after a lapse of a period since the shift of the drive signal from the off state to the on state in comparison to the condition immediately after the shift of the drive signal from the off state to the on state.

Abstract: A power conversion device includes a first capacitor connected in parallel to a direct-current power supply, plural power converters that drive plural synchronous machines, a second capacitor connected in parallel to a direct-current side of power converters, a switching circuit inserted between the first and second capacitors, a switch-start instruction unit that controls starting of an operation of the power converters, and a control unit that controls the power converters based on a motor velocity and a voltage of the first capacitor. The switch-start instruction unit turns off the switching circuit while the power converters stop, turns off the switching circuit until a terminal voltage of each of the synchronous machines becomes equal to a predetermined value when each of the power converters starts operating, and turns on the switching circuit when the terminal voltage of each synchronous machine becomes equal to or smaller than the predetermined value.

Abstract: In a method for reducing the starting current of a multi-phase machine operated by block commutation, which includes a battery, one high side switch for each phase, a low side switch and a phase winding as well as a rotor, the high side switch assigned to one current phase or the low side switch assigned to one current phase is held in the closed state, and the low side switches or the high side switches assigned to the other current phases are alternately controlled.

Abstract: A control device of a three-phase AC motor includes: an inverter; a current sensor for a sensor phase current; and a controller switching a switching element of each phase of the inverter and having a current estimation device, which calculates a sensor-phase-standard current phase according to ? and ? axis currents and a current estimated value of another phase. The current estimation device calculates the ? axis current at every switching and intermediate timings, calculates a first differential value of the ? axis current at every switch timing, calculates the ? axis current according to the first differential value, calculates a second differential value of the ? axis current at every intermediate timing, and calculates the ? axis current according to the second differential value. The intermediate timing is set to have an unequal interval between two adjacent switch timings.

Abstract: A method for positioning a brushless electric drive comprising a stator that has at least one phase winding to which a voltage signal can be applied, and a rotor equipped with magnetic poles. In the method, a voltage signal is applied to the at least one phase winding, the voltage signal generates a magnetic field as a result of the current flowing in the phase winding. The magnetic field putting the rotor into alignment, and as long as the rotor is in motion, the voltage signal is modified in accordance with the intensity of the current induced in the at least one phase winding by the moving rotor, in such a way that the induced current is increased.

Abstract: A motor controller comprises a PWM demodulation processor for re storing speed command value Vr from PWM command signal Si, a rotatio n control section for generating drive value Dd of a motor according to the speed command value Vr, a power drive section for generating driving vol tages Uo, Vo and Wo to energize and drive a motor winding according to the drive value Dd, a rotation speed calculating section for generating dete cted speed value Vd as an information signal to be transmitted to outside, and a PWM modulation processor for generating PWM information signal Fp pulse-width modulated by detected speed value Vd. The PWM modul ation processor outputs the PWM information signal Fp generated in sync hronization with the PWM command signal.