Abstract: A frequency multiplier circuit includes a frequency multiplier, a phase detector and a control circuit. The phase detector detects a difference between an input phase of an input to the frequency multiplier and an output phase of an output from the frequency multiplier. The control circuit is configured to maintain the output phase based on the difference detected by the phase detector.

Abstract: A linear compressor and methods of operation, for example, to detect polarity for the linear compressor are provided herein. The method may include supplying an initial time varying voltage to the motor of the linear compressor at an assumed polarity; estimating a first acceleration of the motor of the linear compressor when the motor is at a bottom dead center position; estimating a second acceleration of the motor of the linear compressor when the motor is at a top dead center position; comparing the first acceleration to the second acceleration; and determining whether the assumed polarity is correct based on the comparison.

Abstract: A calculation apparatus 100 includes an encoder 101 configured to detect rising edges of PWM signals having at least three or more phases in each of the phases, and a register 103 configured to store, at a timing after the PWM signals having the respective phases rise and after AD conversion of a current value of a drive signal of a motor obtained by the PWM signals, a difference value between the AD-converted current value and a previous AD-converted current value for each phase.

Abstract: A single phase motor drive circuit for driving a single phase motor, comprising: a timer unit for receiving a sensor signal indicative of an angular position of a rotor, and for providing a timing signal in phase with the sensor signal; a waveform generator for generating an waveform for energizing the motor, the waveform generator being adapted for receiving the timing signal and at least one configurable setting (Soff), and for generating the waveform based thereon; a configuration unit adapted for receiving a first input signal indicative of a desired motor speed and a second input signal (Vbat) indicative of the supply voltage, and for determining the configurable setting based on the input signals, and for providing the setting to the waveform generator to dynamically configure the waveform generator. A method of driving a single phase motor.

Abstract: In certain embodiments, a method includes transmitting, by a first node, a first signal with a first frequency. The method includes receiving a second signal with a second frequency by downmixing the second signal to an intermediate frequency. The method includes determining a first value of a first phase for the second frequency. The method includes transmitting a third signal with a third frequency, the first frequency and the third frequency having a frequency difference, and receiving a fourth signal with a fourth frequency, the second frequency and the fourth frequency having the frequency difference. The method includes determining a second value of the first phase for the fourth frequency. The first frequency and the second frequency are spaced apart by an amount of the intermediate frequency, and the third frequency and the fourth frequency are spaced apart by the amount of the intermediate frequency.

Abstract: Aspects of the disclosure provide an apparatus that includes a baseband processing circuit and a transmitting circuit. The baseband processing circuit is configured to encode a reference signal based on a specific sequence to generate a digital stream. The specific sequence has non-zero values at selected positions, and the number of coincidences of non-zero value positions between the specific sequence and a shifted copy of the specific sequence is smaller than a threshold. The transmitting circuit is configured to transmit wireless signals in response to the digital stream.

Abstract: When a failure of current detection parts occurs while a synchronous machine is operating, the failure of the current detection parts is detected and the operation of the synchronous machine is continued. An open-loop control part for performing control without using the detected current values of the current detection parts and a closed-loop control part for performing control using the detected current values are included, and a failure of the current detection parts is detected while the open-loop control part is operating.

Abstract: An IGBT/FET-based energy savings device, system and method wherein a predetermined amount of voltage below a nominal line voltage and/or below a nominal appliance voltage is saved, thereby conserving energy. Phase input connections are provided for inputting analog signals into the device and system. A magnetic flux concentrator senses the incoming analog signal and a volts zero crossing point detector determines the zero volts crossing point of the signal. The positive half cycle and negative half cycle of the signal are identified and routed to a digital signal processor for processing the signal. The signal is reduced by pulse width modulation and the reduced amount of energy is outputted, thereby yielding an energy savings for an end user.

Abstract: A method and system for a control circuit are provided. The circuit includes an integrating counter coupled to a process wherein the integrating counter is configured to integrate over time a process parameter signal received from the process and to generate a trigger signal when the integrated signal equals a predetermined count. The control circuit also includes a transition controller electrically coupled to a respective control element and configured to receive the trigger signal generated by the integrating counter.

Abstract: An encoder signal processing circuit is connected to encoder heads outputting an encoder signal in accordance with a relative displacement with respect to a corresponding scale in such a way that signals can be transmitted to and received from the encoder heads, and processes encoder signals from the encoder heads. The circuit includes a processing unit and a processing decision unit. The processing unit generates displacement information from the encoder signal. The processing decision unit decides at least one of content of processing for the encoder heads and content of processing on encoder signals read from the encoder heads after starting to read an encoder signal from one of the encoder heads.

Abstract: A method and a device process a motor signal of a direct current motor, in particular of an adjustment drive of a motor vehicle. The armature current and the motor voltage of the direct current motor are detected and used for determining the counter induction voltage of the direct current motor, by which a number of control signals having different ripple frequencies for controllable frequency filters are generated. The current ripples that are generated in a frequency dependent manner by the frequency filters, to which a filter input signal derived from the armature current and the motor voltage is applied, are synchronized with each other in the course of the ripple count.

Abstract: A method for adjusting a resolver of an electric machine is provided. A resolver rotor is an adjustable element of the resolver and mounted by friction on a support so that a relative angular position with respect to the support may be adjusted by exerting a torque between the resolver rotor and the support. The method includes steps of: measuring an offset angle of the resolver to be corrected; as long as the offset is not less than an predetermined tolerance, locking the resolver rotor with respect to a resolver stator; launching the correction by energizing a main stator of the electric machine so that the electric machine develops a correction torque causing rotation of the resolver rotor with respect to a shaft of the electric machine by the measured offset; and freeing the resolver rotor. Subsequently the method returns to the measuring step.

Abstract: Two excitation coils (excitation A coil, excitation B coil) and two detection coils (detection A coil, detection B coil) are provided. The excitation A coil and the excitation B coil are excited at frequencies that are different from each other. The number of turns of the detection A coil and the detection B coil are respectively set with two sine waves using the number ms1 and ms2 of pole pairs. The number ms1 and ms2 of pole pairs, the number mx1 and mx2 of pole pairs of the excitation A coil and the excitation B coil, and the number mr of pole pairs of a rotor are set to have a predetermined relationship. A resolver having redundancy can be realized with small number of coils.

Abstract: An apparatus for measuring an error in a resolver includes a first calculator that perform an inverse Park transform based on voltages Uq and Ud at an output of PI current regulators, and delivers voltage setpoint signals PWMA, PWMB, PWMC to a power stage via a line on which a DC voltage Ubus-dc is available. The power stage generates a three-phase system of voltages UA, UB, UC for energizing an electric machine. The apparatus also includes a signal processor that provides an angle measurement ?m. Based on currents MesIA, MesIB, MesIC of the three phases, and on a rotor angle ?r, a second calculator of the device delivers values MesId, MesIq used by the first calculator. A PI voltage regulator delivers an angle ?c for correcting the error by regulating a setpoint value for the voltage Ud.

Abstract: A control command generator that generates an armature interlinkage flux command and a torque current command by a torque command, a rotation speed, and an operation target command, includes a first flux command generator generating a first flux command by the toque command or the torque current command, a second flux generator generating a second flux command by the torque command or the torque current command and the rotation speed of the synchronous machine, a command allocation setting unit setting an allocation coefficient equivalent to an allocation ratio of the two first and second flux commands by the operation target command, a flux command adjuster outputting an armature interlinkage flux command by the two flux commands and the allocation coefficient, and a torque current command generator generating the torque current command by the torque command and the armature interlinkage flux command.

Abstract: Provided is an AC motor in a three-phase unbalanced state such as a claw-teeth type AC motor (108), which is reduced in magnetic flux pulsations and torque pulsations. Among the current command values of individual phases to be intrinsically given to an inverter (106) for feeding three-phase alternating currents of variable voltages/frequencies to the electric motor, a current command of an intermediate phase (a V-phase) having a smaller magnetic resistance of a stator core than those of other phases is subjected to a reducing correction by a correction unit (102) on the basis of the correction amount calculated by a current correction amount calculating unit (103), and the unbalanced three-phase alternating currents are fed to the AC motor (108), so that magnetic flux pulsations of a secondary electric angle and torque pulsations of the same order are reduced.

Abstract: A synchronous control apparatus to synchronously control a plurality of motors with respect to a control subject includes a command device and a plurality of motor control devices. The control subject includes the motors, a plurality of position detectors configured to detect a plurality of position information of the motors respectively, and at least one coupler connecting movable axes of the motors. The command device includes a first position controller which is configured to compute a work position based on the position information detected by the position detectors and which is configured to compute, based on a difference between a position command and the work position, a new position command. Each of the motor control devices includes a second position controller configured to compute commands to drive the plurality of motors based on a difference between the new position command and the position information.

Abstract: The invention provides a driving circuit for a voice coil motor. In one embodiment, the driving circuit includes a logic circuit, a digital-to-analog converter, and an output circuit. The logic circuit generates a series of samples of a digital output signal according to a digital input signal, wherein the samples of the digital output signal sequentially alter from a first input value of the digital input value to a second input value of the digital input signal according to an alteration pattern determined by a mode selection signal. The digital-to-analog converter converts the digital output signal to an analog output signal. The output circuit generates a driving current signal according to the analog output signal for driving the voice coil motor.

Abstract: A torque measuring device for determining properties such as viscosity, shearing force or concentration in liquids or suspensions. The device comprises two elastically connected concentric axles in the form of one external hollow axle through which an inner measuring axle extends, and an element responsive to the measured medium located on a distal end of the measuring axle. The axles are individually propelled by electrical motors. The motors are operated such that the axles rotate at generally constant speed and, simultaneously, the phase between the two are controlled irrespective of applied speed and torque. The torque is measured through the degree of load of the motor propelling the inner axle, which is provided as an output signal.

Abstract: A control device for a travel motor mounted to a vehicle has a resolver which works as a rotation-angle sensor. The control device has a RDC which calculates a rotation-angle output value ? based on rotation detection signals Sa, Sb transferred from the resolver. The control device supplies electric power to the travel motor based on the rotation angle output value ?. The RDC calculates “sin(???)” as an error deviation ? based on the signals Sa and Sb and the rotation-angle output value ?. The RDC calculates an angular acceleration by multiplying the error deviation ? with a gain (=Ka·Kb), and integrates the angular acceleration two times in order to obtain a next rotation-angle output value. A gain control part of the RDC decreases the gain when the judgment means judges that the travel motor rotates at a constant rotation speed.

Abstract: A servo control apparatus capable of suppressing adverse effects of disturbance, load variation and the like, and realizing robust and high-performance speed control. The apparatus includes both of the following observers: a disturbance observer for adding a disturbance compensation torque Tf, calculated from a torque command T* and an electric motor rotational speed ?m, to a torque command basic signal T0*, calculated on the basis of a deviation between a speed command ?* and a feedback speed ?f by a PI control section, thus outputting the torque command T*; and a phase advance compensation observer for generating, from the torque command basic signal T0* and the electric motor rotational speed ?m, an output of a nominal plant serving as an element in which no delay occurs, thus outputting the output as the feedback speed ?f.

Abstract: A method of controlling a current of a three-phase electric motor with a three-phase controller. The firing angles are adjusted so as to leave a range of firing angles in which DC components appear.

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

Abstract: A detecting circuit, which can detect plural types of servo signals, including a cosine/sine value detector for sampling a servo signal supplied from an inspected object and thereby obtaining a cosine value and a sine value, an amplitude/phase detector for obtaining at least amplitude information and phase information on the basis of the cosine value and the sine value obtained by the cosine/sine value detector, and a servo selector/position detector for selecting a servo scheme of the inspected object and detecting a position of the inspected object on the basis of the amplitude information and the phase information obtained by the amplitude/phase detector.

Abstract: A drive unit includes a rotating electrical machine; a rotation sensor that detects a rotational position of a rotor of the rotating electrical machine, and a storage medium. In an inspecting step of measuring a counter electromotive force by mechanically driving the rotating electrical machine after the rotating electrical machine and the rotation sensor are assembled together, positional error information of the rotation sensor obtained based on information of the counter electromotive force and output information from the rotation sensor is stored in the storage medium. The storage medium is integrally provided to the drive unit in such a state that the storage medium is readable upon assembling a control device that controls the rotating electrical machine.

Abstract: An electric motor control device includes a power supply unit that supplies power to a three-phase electric motor; a three-phase current sensor that individually detects three respective phase currents of the three-phase electric motor; a summing unit that calculates a three-phase sum by adding the three phase currents detected by the three-phase current sensor; a detected current correction unit that calculates correction amounts for at least two of the three phase currents based on a phase and an amplitude of the three-phase sum and then corrects phase current detection values by the calculated correction amounts; and a motor control unit that controls a power supply by the power supply unit to the three-phase electric motor by feedback control based on the three phase currents after correction by the detected current correction unit and on target currents.

Abstract: A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

Abstract: The present invention relates to a system of controlling a piston in a linear compressor, a method of controlling a piston in a linear compressor, as well as a linear compressor, particularly applicable to cooling systems that may include, for instance, refrigerators, air-conditioning systems and the like.

Abstract: A signal processing device processes a position information signal (A sin?, A cos?) output from a sensor in accordance with a driving position of a motor and detects a driving speed of the motor. The signal processing device includes a position information signal processor (410) that processes the position information signal and calculates driving speed information of the motor, and an internal position information generator (460) that reflects a latest driving speed information (?n) calculated by the position information signal processor (410) and generates a latest presumed position of the motor as internal position information. The position information signal processor (410) calculates driving speed information (?n) of the motor based on a difference between the position information signal (A sin?, A cos?) from the sensor and the internal position information (A sin?n, A cos?n) generated by the internal position information generator (460).

Abstract: A method and a controller for controlling a magnetic bearing device, in which a rotor is suspended for rotation around a shaft, are disclosed. Sensor signals are transformed to yield tilt displacement signals (S?x, S?y) which correspond to tilting displacements of the shaft in predetermined directions (x, y). From the tilt displacement signals (S?x, S?y), tilt control signals A?x, A?y) are derived; these are transformed to yield actuator control signals for driving electromagnetic actuators in the magnetic bearing device. According to the invention, tilting displacements for which the tilt vector rotates about the device axis (z) with a first predetermined sense of rotation are controlled separately from tilting displacements for which the tilt direction vector rotates about the device axis (z) with a second sense of rotation opposite to the first predetermined sense of rotation. In this way, control of nutation and precession can be achieved without influence from blade vibrations or shaft bending modes.

Abstract: A control system for a synchronous electric motor controls the synchronous motor so that the phase of a current determined based on a magnetic pole position of a moving element of the motor may shift to a phase where maximum torque may be obtained. A magnetic pole position correcting section determines a magnetic pole position correction to be added to a relative magnetic pole position. In connection with a polarity change determining section which determines whether or not a polarity of an acceleration difference changes, a basic correction adjusting section switches computation between an incremental operation of incrementing a basic correction and a decremental operation of decrementing the basic correction by a correction increment/decrement. When the correction increment/decrement becomes a predetermined lower limit value B or less, the basic correction adjusting section stops the computation. The basic correction at that point is determined as a finally-determined magnetic pole position correction.

Abstract: A DC motor phase estimation algorithm that estimates a speed-related harmonic frequency of a DC motor current under dynamic load conditions having known geometry parameters. The algorithm estimates the phase and magnitude of a complex coefficient in a complex single frequency adaptive filter that receives a primary signal from the motor current and estimates a reference signal using an incident frequency by adapting the complex coefficient to match the magnitude and phase of the speed-related harmonic component of the primary signal. The rate of change of the phase of the complex coefficient is determined by a phase-lock loop coupled to the adaptive filter to adapt a dynamic incident frequency corresponding to a single frequency component of interest in the primary signal. The incident frequency is extracted, and the motor speed is estimated using the extracted incident frequency and the known motor geometry parameters.

Abstract: The invention relates to a brushless DC motor control apparatus controlling the number of revolutions of a brushless DC motor having a rotor with n poles (where n is a natural number) that rotates due to a supply current with m phases (where m is a natural number) supplied to a stator, comprising: a rotation detector part, which counts the number of revolution pulses from the brushless DC motor caused by the rotation of the rotor, a revolution requirement amount input part, which receives the number of revolutions of the brushless DC motor as input and converts it to a corresponding revolution requirement amount, a comparison part, which compares the number of revolution pulses and the revolution requirement amount, and a current controller part, which controls the supply current supplied to the brushless DC motor according to comparison results from the comparison part.

Abstract: Since an abnormality is judged by executing a square calculating process with respect to sin ? and cos ? for detecting an abnormality in an angular resolver, a processing time is elongated, and a burden to a CPU is great. Since the invention prepares a map which can judge whether the combination of sin ? and cos ? is normal or abnormal, and judges by mapping the combination of the detected sin ? and cos ?, a process can be easily executed, a processing speed is high, and a burden to the CPU can be reduced. Further, an assist can be maintained by controlling a motor by a rectangular wave current by detecting a rotation angle signal at low resolution level, such as Hall sensors arranged around the motor.

Abstract: It is an object of the invention to provide a motor control apparatus capable of ensuring a control function even for a large inertia moment ratio.

Abstract: Provided is a motor control circuit in which the circuit structure is not complicated, which has a favorable response to the phase difference signal, and in which the signal variation caused by heat is small. This rotation control circuit of a motor includes: a PWM control circuit of the motor; a rotational speed sensor of the motor; a reference signal generation circuit 10; a phase comparing circuit; and a divider for dividing the detected rotational speed signal of the motor; wherein the phase difference between the signal from the divider and the signal based on the reference signal is sought with the phase comparing unit, and this phase difference signal is supplied to the PWM control circuit.

Abstract: A pulse generator and method thereof. The pulse generator may include a first switching unit receiving a plurality of receiving a plurality of time interval indicators and a first selection signal. The first switching unit may select one of the plurality of time interval indicators in accordance with the first selection signal and may output the selected time interval indicator. The pulse generator may further include a second switching unit receiving a plurality of pulse states and a second selection signal. The second switching unit may select one of the plurality of pulse states in accordance with the second selection signal and may output the selected pulse state for a first time interval, where the first time interval may be determined by the selected time interval indicator.

Abstract: A Motor driving apparatus adjusts activation start timing of high-side activation control signals UU, VU, WU and the low-side activation control signals UL, VL, and WL with a state determination signal SJ in an activation controller 40, in the period from starting to the time when rotor rotating speed reaches a predetermined value, sets the activation start timing earlier than in normal times to perform leading phase activation control, and in normal times when the rotor rotating speed is a predetermined value or more, controls activation start timing in efficient and optimum phase. Hence, the motor driving apparatus can carry out stable PWM sensorless starting without any starting failure such as oscillation, loss of synchronism and reverse rotation and shorten starting time.

Abstract: An AC servo drive without current sensor includes a PI (proportional integration) controller, at least two first-order controllers (polar point and zero point), a decoupling compensator, a coordinate converter, a pulse width modulator, a counter and a speed estimator. The AC servo drive is connected with a servomotor to form an AC servo module. The servomotor comprises an encoder receiving a current command signal from the servo module to function as input current command signal or the d, q axes PI controller and the decoupling compensator. The voltage command signal generated by the d, q axes PI controller and the signal generated by the decoupling compensator form a control signal and input to the coordinate converter. The signal output from the coordinate converter is processed by PWM controller to control the servomotor. Therefore, the deterioration of servo motor control caused by temperature drift and cost can be solved.

Abstract: A method for controlling the release of a brush motor which has applied a load includes several steps. One step includes applying a release current to the brush motor to rotate the brush motor in a direction toward releasing the applied load of the brush motor. Another step includes sensing the commutator bar ripple current of the brush motor. Another step includes determining when to remove the release current using at least the sensed commutator bar ripple current.

Abstract: A method and apparatus for compensating for the asymmetrical phases of a spindle motor in a disc drive are provided. With the apparatus and method, compensation values are learned by sampling speed data during a period of operation of the disc drive where the speed is stable and only one control operation is performed per revolution of the disc. The sampled speed data is used to generate the compensation values for each of the phases of the spindle motor. The compensation values are stored in a compensation mechanism which is used by the spindle motor speed controller to provide compensation for the asymmetrical phases of the spindle motor. During Normal operation, the actual speed output of the spindle motor is measured and is subtracted from a reference speed to generate a difference speed value. Based on the corresponding electrical phase, the correct compensation value is fetched and is subtracted from the difference speed value to obtain a compensated difference speed value.

Abstract: A motor control device that can reduce electrical noise is provided. A motor control device includes an inverter, a current controller, a high frequency wave superpositioner, and a high frequency wave setter. An inverter applies a current to the motor. A current controller outputs a voltage to the inverter according to a current applied to the motor from the inverter. A high frequency wave superpositioner applies a high frequency wave to the voltage from the current controller as a superpositioned wave to infer a position of a rotor in the motor. A high frequency wave setter varies at least one characteristic of the superpositioned wave applied by the high frequency wave superpositioner.

Abstract: An interrupt signal is generated at each of rising timings of PWM signals which are produced on the basis of phase-shifted triangular wave carrier signals for phases, and voltage command values for the phases. At timings of the interrupt signals, A/D conversion of motor currents of the phases detected by a shunt is started. Interrupt signals are also produced at timings of valleys of the triangular wave carrier signals. Additionally, peak interrupt signals and valley interrupt signals are respectively produced at timings of peaks and valleys of triangular wave carrier signals for phases. Based on each of the peak interrupt signals, normality/abnormality of a switching element of an upper side of the phase corresponding to the interrupt signal is checked, and, based on each of the valley interrupt signals, normality/abnormality of a switching element of a lower side of the phase corresponding to the interrupt signal is checked.

Abstract: A system and method for reducing torque ripple in a motor controller includes a step (60) of measuring an output voltage at each phase of the motor controller. A next step (61) includes determining a voltage mismatch between the phases. A next step (62) includes phase grounding one phase of the motor. A next step (63) includes calculating a voltage gain for the phases to compensate for voltage mismatches therebetween. The compensating gain can include a gain and/or offset, which are applied as a function of motor angle and is used to generate a PWM signal for driving the motor with reduced torque ripple.

Abstract: A fan regulation circuit configuration includes an input receiving an input voltage (proportional to fan current and forms a first comparison voltage), a low-pass filter (filters input voltage and a filter output voltage is tapped off as second comparison voltage), a first comparison device for commutation identification (outputs signal indicating a commutation if value of one of the comparison voltages multiplied by first factor is greater than the other comparison voltage), and a regulator (outputs a control voltage dependent upon identified commutation pulses). The circuit has self-adjusting sensitivity adaptation and a second comparison device outputting a signal if the value of one of the comparison voltages multiplied by a second factor is greater than the other comparison voltage, the second factor being less than the first factor.

Abstract: A control system for an electric machine having a rotor position sensor that generates a rotor position signal, a velocity module that generates an electric angular velocity value based on the rotor position signal, a random pulse width modulation module that generates a switching period and a delay for a current cycle, and a phase angle compensation module that sums a sample rate, one half of the switching period, and the delay of a previous cycle and that outputs a delay time. The phase angle compensation module further multiplies the delay time and the electric angular velocity value and generates a compensating angle.

Abstract: A method and apparatus for controlling acceleration and velocity of a stepper motor in which a phase offset is selected depending on motor velocity. The optimal phase offset indicates the position of the winding which generates the maximal driving moment. The increase of the driving force and the extension of the range of steady-state movement is achieved for advanced motor coils commutation with constant frequency using velocity feed back and gradual step-wise phase shift where the phase offset is selected depending on rotor velocity. The invention may be effectively applied to servomotors, stepper motors, motors having certain limitations on movement parameters, such as limitations on acceleration and other types of motors.

Abstract: A method for determining the position of an element driven by the drive shaft of a commutated direct current (DC) motor includes counting current ripples detected in an armature current signal as the motor rotatably drives the shaft. A frequency spectral analysis of the armature current signal is performed to determine frequency components of the armature current signal. The frequency components are analyzed to determine which of the frequency components is indicative of the current ripple frequency. The current ripple frequency is monitored for changes over time while the motor drives the shaft. The number of counted ripples is modified upon a change in the current ripple frequency in a time interval if the current ripple frequency change deviates from the current ripple frequency more than a threshold deviation for the time interval. The rotational position of the shaft is determined based on the modified number of counted ripples.

Abstract: A motor controller capable of obtaining information on offsets, amplitudes and a phase difference of analog feedback signals from encoders without using special measuring device. The analog feedback signals from the encoders are A/D converted and the offsets, the amplitudes and the phase difference of A-phase and B-phase analog feedback signals are obtained based on the converted digital signals by an arithmetic section. The obtained offsets, amplitudes and phase difference are displayed by a display section of the motor controller and/or a display section of a numerical controller as a host controller. Further, the obtained offsets and amplitudes are compared with respective reference values for determining acceptability of the feedback signals from the encoders and the results of the comparison is displayed by the display section and/or the display section of the numerical controller.

Abstract: A method for determining phase current for each of a plurality of individual phase coils of a switched reluctance machine (SRM) is disclosed. In an exemplary embodiment, the method includes determining the current passing through a first resistive element and a second resistive element in an SRM drive circuit. A conduction mode of the SRM drive circuit is determined, the conduction mode being based upon an ON/OFF state of each of a pair of switching transistors controlling current through each of the plurality of individual phase coils. The phase current through each of the plurality of individual phase coils is then calculated, based upon the conduction mode and the determined current passing through said first and second resistive elements.