Abstract: A motor controller comprises a switch circuit and a control unit. The motor controller is used for driving a motor, where the motor has a coil. The switch circuit is configured to supply a coil current to the coil. The control unit is configured to generate a plurality of control signals to control the switch circuit. The motor controller enables a floating phase time to be a variable value, where the floating phase time has a stable interval and a detecting interval. The motor controller enables a zero point of the coil current to appear in the stable interval, so as to detect a phase switching time point in a stable way and avoid a noise problem. The motor controller detects a zero crossing point of a back electromotive force in the detecting interval.

Abstract: A method for increasing a resolution by N bits performed by a processing circuit of a motor driving system, where N is a positive integer, and the method includes: performing a conversion upon an analog command, to generate a command count value; performing a first N-bit right-shifting operation upon the command count value, to generate an initial output value; performing a logical operation upon the command count value, to generate a low bit value; generating an overflow value according to the low bit value; and determining a final output value according to the initial output value and the overflow value.

Abstract: According to one aspect of the present disclosure, there is provided an apparatus that includes a battery, a Direct Current (DC) bus connected to the battery, and a DC to DC converter connected to the battery in parallel with the DC bus. A Motor Control Unit (MCU) is connected between the DC to DC converter and an electric motor. An Alternating Current (AC) port is connected to the electric motor. Switches connect the DC bus and an output of the DC to DC converter in series as an input to the MCU in a drive mode and disconnect the DC bus from the MCU in a charge mode.

Abstract: The present disclosure provides a motor control circuit enabled to change or adjust functions to be implemented to suppress an increase in cycle time during mass production. A motor control circuit according to an exemplary embodiment of the present disclosure is a motor control circuit to control a motor driver including a first non-volatile memory and a second non-volatile memory, and the first non-volatile memory stores a control algorithm and a first parameter group to be used by the control algorithm of the motor control circuit, and the second non-volatile memory is enabled to store a second parameter group to be used by the control algorithm.

Abstract: The object of the invention is a method of controlling a permanent-magnet synchronous or synchro-reluctant three-phase rotary machine (4), comprising the following steps: measuring a current (iA, iB, iC) flowing through each phase of a stator of rotary machine (4); first calculating, by use of a single proportional-integral controller, a switching control signal for controlling an inverter (10), according to each measured current (iA, iB, iC), and of a target value (Tref) of a mechanical torque provided by the rotary machine (4) or of a target value of an angular speed of a rotor of rotary machine (4) in relation to the stator wherein the inverter (10) is configured to convey electrical energy between a continuous electrical energy source (8) and each phase of the stator of rotary machine (4); and controlling the inverter (10) by use of the calculated switching control signal.

Abstract: A motor driver for driving a rotor of a single coil motor in a clockwise or counterclockwise rotation direction concerning a stator of the single coil motor is adapted for generating a position signal which is representative for the angular position of the rotor regarding the stator and comprises a controller which comprises a direction input to define the rotation direction of the rotor, and which is adapted for generating a driving signal for rotating the rotor in the defined rotation direction, wherein the driving signal is based on the position signal and is based on a signal indicative for an electrical lead angle wherein the signal indicative for the electrical lead angle is set such that the total lead angle is positive in both rotation directions of the rotor.

Abstract: A position estimation device acquires detection values of magnetic field strength at three or more locations of a rotor in a range where a rotor angle is less than one rotation. A section is selected based on a detection value of the magnetic field strength from predetermined sections for a pole pair number of the rotor. A feature amount calculator is provided to calculate feature amounts of a waveform of the magnetic field strength based on a combination of the detection values of the magnetic field strength according to the section selected. An estimator is provided to determine, for each segment associated with the section selected, whether or not a magnitude relationship of the feature amounts learned in advance coincides with a magnitude relationship of the feature amounts calculated, and estimating, as a rotation position of the rotor, the pole pair number associated with the segment having the same magnitude relationship.

Abstract: A position estimation method of the present disclosure includes: acquiring learning data from a storage medium that stores the learning data including a sequence of a plurality of measurement values which define a waveform characteristic of a first electrical signal output from a sensor device when a rotor R is rotating; acquiring a sequence of a plurality of detection values which define a waveform characteristic of a second electrical signal output from the sensor device when the rotor starts rotating from a stopped state; and performing matching between an increase/decrease pattern of the sequence of the plurality of measurement values and an increase/decrease pattern of the sequence of the plurality of detection values to estimate a relationship between a rotation position of the rotor when the first electrical signal is output and a rotation position of the rotor when the second electrical signal is output.

Abstract: A motor controller comprises a switch circuit, a driving circuit, and a pulse width modulation circuit. The switch circuit is coupled to a three-phase motor for driving the three-phase motor. The driving circuit generates a plurality of control signals to control the switch circuit. When the three-phase motor is operated in a start state, the motor controller may enable an electric period to be divided into more floating phase time intervals for switching phases, so as to increase the success rate of phase switching. When the three-phase motor is operated in a stable state, the motor controller may enable the electric period to be divided into less floating phase time intervals for switching phases, so as to reduce the noise and vibration of the three-phase motor.

Abstract: The present disclosure describes an apparatus, system, and method of use for detecting electrical faults in a multiphase electric machine. Often in platforms which require redundant reliability or have no readily available electrical connection to earth use ungrounded electrical architectures. This allows the system to continue normal operation even if there is an unintended short circuit or current path (electrical fault) between a phase of an electric machine and its case or some other part of the platform. It is important to be able to readily identify any fault in the phase windings of machinery operating in an ungrounded electrical architecture. Since a single fault in an ungrounded system will not cause any additional current draw or otherwise affect the system, it can be difficult to detect that a fault has even occurred. This provides an advanced warning system.

Abstract: An electric power conversion apparatus includes a first inverter electrically connected to one end of each of phase windings of a motor, and a second inverter electrically connected to the other end of each of the phase windings, and a neutral point potential setting circuit electrically connected to the first inverter to set a potential of a neutral point in the first inverter when the first inverter is determined to be in an abnormal state.

Abstract: A motor starting device includes a starting unit, a driving unit, a floating point selecting unit, a back electromotive force (BEMF) detecting unit and a control unit. In a starting mode, the starting unit generates an initial starting signal having a plurality of phases according to a commutation sequence, the driving unit drives the motor with a first phase in the initial starting signal, the floating point selecting unit selects a floating phase of the motor that is not turned on according to the driving condition of the driving unit, the BEMF detecting unit detects whether the BEMF of the floating phase has a first voltage level or a second voltage level to generate a detection result, and the control unit outputs a phase changing signal to the driving unit according to the detection result.

Abstract: A control system and a control method, used for controlling a motor. The control system includes a central processing module and a drive control module. In a period in which a voltage is not applied to any phase coil of the motor, the drive control module collects voltages of the phase coil, converts the voltages of the coil into digital signals and stores the digital signals. The central processing module reads the digital signals from the drive control module, accumulates the digital signals to obtain an accumulated value, and determines the operating condition of the motor according to a relationship between the accumulated value and a preset threshold, thereby improving the reliability of the motor control.

Abstract: A motor driver device supplies drive voltages to three phase coils of a stator in a brushless DC motor based on a detection result of a position of a rotor in a sensorless manner. In a position detection section, two phase coils are set as a target coil pair and a remaining one phase coil is set as a non-target coil, and with respect to all combinations of target coil pairs, a first process of applying a pulse voltage from a first direction to the target coil pair and a second process of applying a pulse voltage from a second direction opposite to the first direction to the target coil pair are executed. In the first and second processes, power supply to the non-target coil is stopped. The position of the rotor is detected based on voltages generated in the non-target coil in each first process and each second process.

Abstract: In some examples, a device includes a gate driver circuit and a control circuit configured to generate a first signal and a second signal, a duty cycle of the first signal encoding an amplitude of an electrical current having a sinusoidal shape, and a duty cycle of the second signal encoding a phase angle of the electrical current. The control circuit is configured to deliver the first and second signals to the gate driver circuit, which is configured to determine a duty cycle of a driver signal as a function of the first signal and of the second signal. The gate driver circuit is also configured to deliver the driver signal to a switch to cause the electrical current having the sinusoidal shape to be delivered to an electrical load.

Abstract: The junction temperature of a field effect transistor is detected with a higher degree of accuracy than in the past. A semiconductor device controls multiple field effect transistors that configure a power conversion device, and includes a differential amplifier and a controller that controls ON/OFF of the multiple field effect transistors. The differential amplifier detects the potential difference between a source and a drain of a field effect transistor that is controlled in the OFF state by the controller and that induces an electric current flowing through the body diode thereof, among the multiple field effect transistors.

Abstract: An electric motor that is controlled by a motor control device has two-system multi-phase motor coils. The motor control device includes a common mode noise reduction unit that changes a PWM count in a PWM cycle for at least one phase in one of two systems such that a current that flows through a stray capacitance because of an output voltage for one phase in the other system is canceled out with a current that flows through the stray capacitance because of an output voltage for the at least one phase in the one system in at least one PWM cycle in a current control cycle.

Abstract: The present invention relates to an inverter-controlling device. The inverter-controlling device include a main controller configured to generate a predetermined command current; a comparison module configured to calculate a difference between the command current and an output current of an inverting module; a current controller configured to perform a proportional-integral (PI) control based on the difference; and a frequency estimation module configured to estimate a rotation speed of a motor based on a current response to the command current while the command current is injected to the current controller, wherein the main controller is further configured: when a flying start operation of the inverting module begins, to set an output frequency of the inverting module based on the rotation speed of the motor estimated by the frequency estimation module.

Abstract: A controller of a DC brushless motor and a control method thereof are disclosed. The controller is connected to a commutation circuit including three voltage dividers and three comparators. Each voltage divider includes a first resistor and a second resistor connected in series. Each first resistor is connected to a terminal voltage of three-phase coils of the DC brushless motor. Each comparator includes a positive input end connected to a node connected to the first resistor and the second resistor of the corresponding voltage divider and a negative input end connected to the node of the adjacent voltage divider. The controller includes a control circuit and three bias resistors respectively connected to a voltage source and the node of the corresponding voltage divider. The control circuit detects a counter EMF signal of each phase coil and controls the voltage source to supply an offset voltage to the corresponding node.

Abstract: A soft-start control circuit includes first to third inverters, first to third comparators, first to fourth resistors, first to fourth D-type flip-flops and a NOR gate. The first comparator outputs a first trigger signal. The second comparator outputs a second trigger signal. The third comparator outputs a third trigger signal. The first D-type flip-flop outputs a first error amplification ready signal. The second D-type flip-flop outputs a second error amplification ready signal. The third D-type flip-flop outputs a high-level output voltage ready signal. The fourth D-type flip-flop outputs a low-level output voltage ready signal. The NOR gate receives an inverted signal of a high-level output voltage enable signal and the third trigger signal and outputs a high-level output voltage control signal to prevent an inrush current of the DC-DC conversion system during a startup process.

Abstract: A filter for use with a brushless DC motor to filter a signal received from a floating terminal of the brushless DC motor, wherein the filter is configured such that a time delay introduced by the filter to the signal received from the floating terminal is equal to the time taken for a rotor of the motor to rotate through an angle equal to half of a commutation step of the motor.

Abstract: A phase detecting device includes a signal level detector configured to detect a first level of a signal according to a phase of a rotor of a motor, a level memory configured to store the first level of the signal preliminarily detected at each phase of the rotor as a second level of the signal at the phase of the rotor, and a phase detector configured to detect the phase of the rotor based on the second level of the signal inputted from the signal level detector.

Abstract: A semiconductor device includes a pulse generation circuit which generates a pulse control signal for selectively supplying currents to the coils with the coil phases of the brushless DC motor, a selector circuit which selects arbitrary two signals, from detection signals corresponding to currents flowing respectively to the coils and a reference signal, a comparator circuit which compares the two signals selected by the selector circuit, timer counter, and a control circuit. The control circuit repeatedly controls an operation for the pulse generation circuit to output a pulse control signal for supplying electricity to one of the coil phases in a state where the rotor is stopped, an operation for the selector circuit selects the reference signal and one of the detection signals, from the detection signals.

Abstract: A sheet conveying apparatus for conveying a sheet includes a conveyance roller, a motor, a phase determiner, and a controller. The phase determiner determines a rotor rotation phase of the motor that drives the conveyance roller to convey the sheet. The controller controls so that a value of a rotor torque current component becomes a target value of the torque current component and controls so that an excitation current component value becomes a target value of the excitation current component, and controls to reduce a deviation between a command phase and the determined rotation phase. The controller controls so that a magnetic flux penetrating through a winding is weaker than a magnetic flux of the rotor, and so that a magnetic flux penetrating through the winding in a second period is stronger than the magnetic flux penetrating through the winding in the first period.

Abstract: A method for determining the state of a brushless motor having first, second and third phases, in some embodiments, comprises: decoupling said motor from a power source; determining whether said motor is rotating or non-rotating; if the motor is rotating, determining a first phase voltage state relative to a common voltage and a second phase voltage state relative to the common voltage, said first phase and second phase voltage states determined when a third phase voltage is within a predetermined range of said common voltage; and if the first phase voltage state and the second phase voltage state are the same, repeating said determination as to whether the motor is rotating or non-rotating.

Abstract: A hybrid rectifier is provided including a top diode for conducting current during a positive current portion of a line current, a top transistor connected in parallel to the top diode, a bottom diode for conducting current during a negative current portion of the line current, and a bottom transistor connected in parallel to the bottom diode. A hybrid-rectifier controller is connected to the top transistor and the bottom transistor for implementing a transistor control strategy such that, during the positive current portion of the line current, the top diode conducts current and the bottom transistor conducts current only when the line current is below a sinusoidal reference current. Similarly, during the negative current portion of the line current, the bottom diode conducts current and the top transistor conducts current only when the line current is above the sinusoidal reference current.

Abstract: A sensor device includes a main sensor, a sub sensor, and an Electronic Control Unit (ECU). The ECU has a torque calculator that sets, as a steering torque, a main steering torque that is calculated based on a main sensor signal when a main output signal is normal. During a transition period between an abnormality detection and an abnormality establishment regarding the main output signal, the torque calculator calculates the steering torque based on (i) a sub steering torque calculated based on a sub sensor signal and (ii) a prior-to-abnormality-detection main steering torque. In such manner, even when abnormality is detected in a part of the sensor signals, a fluctuation of the steering torque due to, or accompanying, the switching of the steering torque calculation to a normal signal only calculation is prevented.

Abstract: A single phase brushless DC motor comprises a Hall effect sensor, a coil assembly and a motor control circuit which generating a driving signal to guide a coil current flowing through the coil assembly. The Hall effect sensor senses the magnetic pole of the rotor to accordingly generate a Hall effect signal. The motor control circuit outputs a current polarity reverse signal according to the voltage at one end of the coil assembly. The time when the current polarity reverse signal is generated corresponds to the polarity reverse time of the coil current. The motor control circuit adjusts the phase of the driving signal according to the polarity reverse time of the Hall effect signal and the time when the current polarity reverse signal is generated to synchronize the phase of the back emf of the single phase brushless DC motor with the phase of the coil current.

Abstract: A driver device for driving a DC motor using PWM modulated drive signals includes comparator circuits for producing digitalized Back-EMF signals having first and second values as a function of the Back-EMF signals being above or below a respective threshold, and an inverter for driving the PWM modulated drive signals in a phased relationship with the digitalized Back-EMF signals. The driver device also includes controller circuits configured for controlling the respective threshold by minimizing the error between a time measured between two consecutive opposed edges of the digitalized Back-EMF signal and half a time measured between two consecutive homologous edges of the digitalized Back-EMF signal.

Abstract: A phase detector is provided. The phase detector includes a signal selector, a bias level generator, and a phase information detector. The signal selector selects, as a selected sensor signal, one of a plurality of sensor signals each having a signal level corresponding to a phase of a rotor. The bias level generator divides a signal level difference between a pair of sensor signals, including the selected sensor signal and other sensor signal of the plurality of sensor signals other than the selected sensor signal, at a first ratio, to generate a first bias level. The phase information detector generates a threshold level corresponding to the phase of the rotor based on the first bias level, and detects the signal level of the selected sensor signal reaching the threshold level.

Abstract: A position sensing system including a waveguide, a magnet movable relative to the waveguide, and a compensator configured to compensate for a change in propagation velocity of the waveguide in determining a position of the magnet relative to the waveguide. The compensator coupled to the waveguide and configured to receive a pulse, an end of line pulse corresponding to the pulse transmitted through the waveguide, and a reflected pulse corresponding to a reflection of the pulse at a point in the waveguide. The compensator configured to determine the point based at least in part on the pulse, the end of line pulse, and/or the reflected pulse.

Abstract: A predetermined timing is a timing at which the sampling timing is in a vicinity of a maximum peak position of the carrier wave signal and a timing at which the sampling timing is in a vicinity of a minimum peak position. The demodulation arithmetic section outputs, as the demodulation calculated result, a value d3 calculated with d3=(d1?d2)/2 when a data value of the digital signal sampled in the vicinity of the maximum peak position is denoted by d1 and a data value of the digital signal sampled in the vicinity of the minimum peak position is denoted by d2.

Abstract: A method for controlling an ECM motor to output a constant torque. The method includes: 1) entering a target torque value T0 from an external device; when the motor is in a non-use state, starting the motor, and allowing the microprocessor to acquire an original output voltage value P chopped by a PWM signal; when the motor is in a running state, allowing the microprocessor to acquire a current output voltage value P chopped by the PWM signal; 2) enabling the microprocessor to calculate a target bus current value Itad using the function Itad=F(T,P) according to the target torque value T0 and the output voltage value P chopped by the PWM signal; and detecting a real-time bus current Ibus; and 3) allowing the microprocessor to compare the target bus current value Itad with the real-time bus current Ibus for conducting a closed-loop control.

Abstract: A method for determining the rotary position of the rotor of an electric machine, which includes star-connected phase conductors, wherein a measurement signal representing the rotary position of the rotor within a magnetic half-period is determined from the potential at the star point. At a measurement time a specified voltage is applied to the ends of all the phase conductors by forcing the star point to a specific potential. At a time following the measurement time a voltage that deviates from the specified voltage is applied to the ends of one of the phase conductors. Then the measurement signal is derived from the current that develops from the measurement time in a connection of the star point to the specified potential.

Abstract: An anti-rebounding control apparatus is provided, which includes an anti-rebounding controller outputting a first command for setting a torque limit value to “0” if an electric motor speed value is equal to or smaller than an upper threshold value and equal to or larger than a lower threshold value in the case where a speed command value of “0” is input and outputting a second command for setting the torque limit value to a maximum value if the electric motor speed value is smaller than the lower threshold value, a torque regulator setting the torque limit value to “0” when the first command is input and setting the torque limit value to the maximum value when the second command is input, and an electric motor inverter intercepting a power that is supplied to an electric motor if the torque limit value is set to “0” and re-supplying the power to the electric motor if the torque limit value is set to the maximum value.

Abstract: A method for controlling an ECM motor to output a constant torque. The method includes: 1) entering a target torque value T0 from an external device; when the motor is in a non-use state, starting the motor, and allowing the microprocessor to acquire an original output voltage value P chopped by a PWM signal; when the motor is in a running state, allowing the microprocessor to acquire a current output voltage value P chopped by the PWM signal; 2) enabling the microprocessor to calculate a target bus current value Itad using the function Itad=F(T,P) according to the target torque value T0 and the output voltage value P chopped by the PWM signal; and detecting a real-time bus current Ibus; and 3) allowing the microprocessor to compare the target bus current value Itad with the real-time bus current Ibus for conducting a closed-loop control.

Abstract: To provide a motor control circuit that variably controls the speed of a motor, in which an appropriate advance angle value corresponding to the speed of the motor that is set can be automatically set. The motor control circuit according to the present invention includes an advance angle setting means that adds a reference advance angle value to an advance angle correction value obtained by multiplying a proportional coefficient by a correction amount and outputs an advance angle setting signal, and an advance angle setting correction means that uses a ratio of a correction reference period relative to a period of a reference signal input from the outside as a correction amount and corrects the reference advance angle value by an advance angle correction value obtained by multiplying the correction amount by a predetermined proportional coefficient of the advance angle setting means.

Abstract: There is provided a power controller including a drive circuit connected to a DC power supply to apply a first voltage to the drive circuit and configured to supply power to an external load, a current detection circuit configured to detect a current flowing in the drive circuit by converting the current into a second voltage corresponding to the current, and a current-voltage control unit configured to generate a reference voltage corresponding to a limit value of the current flowing in the drive circuit when the first voltage is applied to the drive circuit, and configured to control the drive circuit to operate in a desired current according to the first voltage, based on a comparison result of the reference voltage and the second voltage.

Abstract: The system discloses structure for synchronizing sequential phase switching in driving a set of stator windings of a multi-phase sensorless brushless permanent magnet DC motor. A drive voltage drives a plurality of the stator windings thereby producing a magnetic field. On an undriven stator winding among the stator windings, a voltage induced by the magnetic field is sampled. The induced voltage changes as a function of a magnetic rotor transitioning across a plurality of angular positions. A first value corresponding to the sampled voltage induced on the currentless winding is compared with a commutation threshold to determine a proper commutation point. The system is switched to a next drive configuration of the sequence when the first value surpasses the threshold.

Abstract: A motor control apparatus includes: duty calculation units that calculate a duty of a PWM signal based on a deviation between a value of a physical quantity of a motor with a command value; and a duty setting unit that performs setting of the duty based on the duty calculated by the duty calculation units. The duty setting unit maintains a present duty until new duty is input from any one of the plurality of duty calculation units, and updates the duty from the present duty to the new duty when the new duty is input from any one of the plurality of duty calculation units. A PWM signal generation unit generates the PWM signal based on the duty set by the duty setting unit and a carrier signal generated by a carrier signal generation unit.

Abstract: Provided are a motor controller for suppressing a torque pulsation with a simple configuration and obtaining a sufficient output torque in the case of an open-type fault occurring in any one of windings of a motor and inverters, and an electric power steering device using the motor controller. In the motor controller for controlling a current supplied from and a voltage applied from a power source with respect to the motor including winding sets of a plurality of systems, when a fault determination unit (31) determines the occurrence of the open-type fault, the supply of the currents to the windings of one of the systems in which the fault has occurred is stopped by control performed on switching elements included in the inverter of the faulty system, whereas the supply of the currents to the windings of the normal system in which the fault has not occurred is continued.

Abstract: A multi-phase motor control method controls a multi-phase motor which includes multiple nodes respectively receiving a corresponding number of driving voltage signals to control a rotation of a rotor. The motor control method includes: sensing a signal phase of a current signal corresponding to at least one node, for example by sensing a zero-crossing point of the current signal; determining a reference phase for the current signal; calculating a phase difference between the signal phase and the reference phase; and controlling a phase switching frequency of the stator according to the phase difference, such that the signal phase is close to or in phase with the reference phase, to thereby obtain an optimum rotation speed of the rotor corresponding to a given driving voltage. The present invention also provides a multi-phase motor control device using the motor control method.

Abstract: A motor control apparatus has an inverter circuit having a plurality of pairs of upper and lower arms provided so as to correspond to the number of phases, and switching elements provided on each of the upper arms and the lower arms of each phase that drive a motor on the basis of ON or OFF operations of the respective switching elements, a single current detector that detects a current of the motor flowing through the inverter circuit, and a duty calculator that calculates duties of a PWM signals for turning the switching elements ON or OFF on the basis of a deviation between a current value of the current detected by the current detector and a target current value.

Abstract: A motor driving apparatus according to an embodiment includes a brushless motor. The motor driving apparatus includes a position sensor that outputs a position detection signal in synchronization with a phase of an induced voltage of a coil of the brushless motor. The motor driving apparatus includes a semiconductor integrated circuit that controls driving of the brushless motor by supplying a pseudo sine-wave driving voltage from an energization terminal to the coil of the brushless motor based on the position detection signal and a command signal that prescribes driving of the brushless motor.

Abstract: The present invention discloses a controller and a method for improving motor driving efficiency. According to the present invention, multiple control parameters are inputted to the controller so that the controller can adjust timings of PWM driving signals for driving the motor to advance or delay the turned-ON or turned-OFF points, whereby the motor is driven efficiently.

Abstract: A circuit includes a processor that analyzes a pulse width modulated (PWM) signal feedback from a brushless DC motor to determine a transition between a mutual inductance zero crossing condition and a Back Electro Motive Force (BEMF) zero crossing condition of the brushless DC motor. A mutual inductance controller is executed by the processor to commutate the brushless DC motor at startup of the motor when the mutual inductance zero crossing condition is detected by the processor. A BEMF controller is executed by the processor to commutate the brushless DC motor after startup of the motor when the BEMF zero crossing condition is detected by the processor.

Abstract: A method for driving a brushless direct current (DC) motor is provided. The brushless DC motor has a first phase that is coupled between a first terminal and a common node, a second phase that is coupled between a second terminal and the common node, and a third phase that is coupled between a third terminal and the common node. The first and second phases are coupled to a first supply rail and a second supply rail, respectively, such that the brushless DC motor is in a first commutation state. The first phase is then decoupled from the first supply rail so as to allow first terminal to float during a window period. A first voltage difference between the first terminal and the second terminal is compared to a second voltage difference between the third terminal and the second terminal during the window period, and the brushless DC motor is commuted to a second commutation state if the first voltage difference is approximately equal to the second voltage difference.

Abstract: A motor driving circuit includes a magnetic-pole-position detecting unit that detects a rotating position of a rotor of a permanent magnet synchronous motor, a voltage output unit that converts a direct-current voltage and generates a driving voltage for the permanent magnet synchronous motor, a voltage control unit that controls the voltage output unit on the basis of a comparison result of a modulation wave and a carrier wave, a voltage-phase adjusting unit that determines, using a differential amplifier circuit that receives a rotating speed control signal and an offset signal, a phase of the modulation wave generated by the voltage control unit and causes the voltage control unit to generate the modulation wave in the determined phase, and an offset generating unit that generates the offset signal.

Abstract: A motor control circuit and associated techniques can adjust a phase of a motor drive to keep a rotational reference position of an electric motor at the same relative phase as a zero current in a motor winding at different motor speeds and as the motor accelerates and decelerates. In some embodiments, a particular circuit and technique can be used to detect the zero current in the motor winding.

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.