Abstract: A control device for an electric motor includes a control circuit that controls an operation of an inverter circuit on the basis of a voltage command value corresponding to a difference between a current command value calculated on the basis of the position of a rotor of the electric motor, and a current flowing through the electric motor. A current estimation unit estimates the current flowing through the electric motor by substituting the voltage command value, a parameter unique to the electric motor, and a rotational speed calculated on the basis of the position of the rotor into a voltage equation serving as a model of the electric motor. An LR estimation unit estimates an inductance and a resistance of the electric motor serving as parameters on the basis of the difference between the current obtained by a current acquisition unit and the current estimated by the current estimation unit.

Abstract: A microelectromechanical gyroscope includes a drive loop having a drive element and a drive loop circuitry. The drive loop circuitry includes a clock generating circuitry for generating from the quadrature-phase detection signal a test clock signal, an angular rate phase demodulation signal and a quadrature phase demodulation signal. A sense loop includes a sense element and sense loop circuitry for detecting angular rate and producing a force-feedback signal. A test signal generator receives a quadrature-phase detection signal to be used as a quadrature-phase carrier signal and the test clock signal A summing element sums a test signal with the force-feedback signal to form a sense feedback signal. A rate phase demodulator produces a rate signal by demodulating a sense signal received from the sense loop with the angular rate phase demodulation signal, and a quadrature-phase demodulator produces a quadrature-phase output signal.

Abstract: An electric motor control device includes a drive waveform generating unit configured to generate a drive waveform (a sine wave or a pseudo-trapezoidal wave) to an electric motor. A plurality of photo interrupters detect a rotational phase of an electric motor, and a information of rotational speed is detected by an encoder circuit based on a detected signal of the rotational phase of the electric motor. The control unit controls the drive waveform generating unit on the basis of detection information of the rotational phase of the electric motor and performs control so that a phase relationship between the rotational phase of the electric motor and the phase of the drive waveform is kept constant. Furthermore, the control unit sets an amplitude value of the drive waveform generated by the drive waveform generating unit in accordance with a difference between a target speed and the detected information of rotational speed and performs speed control so that a speed of the electric motor is kept constant.

Abstract: A variable speed drive for an electrostatic motor provides feedback control by conversion of measured current phases provided to the motor into a vector in a rotating rotor framework. This vector is used for evaluating corrective voltages and then reconverted to a non-rotating framework for application to the motor electrodes. Current-source drive circuits provide current stabilized outputs making such sophisticated control tractable.

Abstract: A system and methods are provided for controlling a motor of a rod pumping system using previous RPMs of the motor and predicting an RPM of the motor; correcting a power factor of a motor of a rod pumping system; allocating energy consumption and allocating energy generation for a set of wells connected to an electricity meter using an amount of energy generated by each well; and generating an alert if a set of data is beyond a threshold for the set of data.

Abstract: Disclosed are a method and system of controlling anti-jerk for reducing vibration of an electric vehicle using power of a motor. The method includes outputting an actual speed of the motor; outputting a model speed of the motor; obtaining a vibration component based on a deviation between the output motor speed and actual speed of the motor; high pass filtering the vibration component to remove an error component in the vibration component; delaying a phase of the filtered vibration component for a preset time to compensate for phase error occurring during the high pass filtering; and applying a preset gain to the vibration component in which the phase is delayed for the preset time to generate an anti-jerk compensation torque based on the applying of the preset gain.

Abstract: A converter includes three AC reactors, a three-phase diode bridge, a plurality of smoothing capacitors connected in series between a DC output side of the three-phase diode bridge and a DC load, two flywheel diodes connected to positive and negative terminals on the DC side of the three-phase diode bridge, respectively. A reactor is inserted between the midpoint of the two flywheel diodes and the midpoint of the smoothing capacitors, three both-way energizing switches are arranged between the AC side of the three-phase diode bridge and the midpoint of the two flywheel diodes. The three both-way energizing switches are controlled to reduce higher harmonic components of power source current, and by the reactor interposed between the midpoint of the two flywheel diodes and the midpoint of the smoothing capacitors, reverse recovery currents of the three-phase diode bridge during turn-on of the three both-way energizing switches are suppressed.

Abstract: In a motor, a stationary member is provided with a number M (M is a positive integer) of first poles within 360 electrical degrees at spaces therebetween. A plurality of windings are at least partly wound in the spaces, respectively. A movable member is movably arranged relative to the stationary member and provided with a number K (K is a positive integer) of second poles. The number K of second poles is different from the number M of first poles. A unidirectional current supply unit supplies a unidirectional current to at least one of the windings so as to create an attractive force between at least one of the first poles and a corresponding at least one of the second poles to thereby move the movable member relative to the stationary member.

Abstract: A method of controlling an AC machine that includes a stator and a rotor. The method includes observing a stability parameter that is indicative of the stability of the AC machine and dependent on a current state of the AC machine; and controlling the AC machine based on the observed stability parameter so as to promote stable operation of the AC machine. The method may include controlling the AC machine to operate as a motor or as a generator. The AC machine may be a permanent magnet synchronous machine. A controller suitable for performing the method is also disclosed.

Abstract: A power supply circuit for an electric motor, the circuit comprising a plurality of inverter bridge arms, each having means for connection to a respective winding of the motor, each inverter bridge arm comprising in series a first insulated gate bipolar transistor and a junction field effect transistor that are connected to a controller, the circuit including a second insulated gate bipolar transistor connected in series with each field effect transistor and connected to the controller, and a damping resistor connected in parallel with the second bipolar transistor. An aircraft flight control member including a movable airfoil associated with at least one drive motor connected to such a power supply circuit.

Abstract: A torsional mode damping controller system connected to a converter that drives a drive train including an electrical machine and a non-electrical machine. The controller system includes an input interface configured to receive measured data related to variables of the converter or the drive train and a controller connected to the input interface. The controller is configured to calculate at least one dynamic torque component along a section of a shaft of the drive train based on the measured data from the input interface, generate control data for a rectifier of the converter for damping a torsional oscillation in the shaft of the drive train based on the at least one dynamic torque component, and send the control data to the rectifier for modulating an active power exchanged between the converter and the electrical machine.

Abstract: The present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage, and a current control gain adjusting step of calculating a current control gain based on frequency characteristics of the applied voltage and the motor current. In this manner, a stable current control gain having a high current response can be adjusted within a short period of time.

Abstract: Disclosed herein is a torque control method for a high-speed Switched Reluctance Motor (SRM), which controls a torque in the high-speed operation of a 2-phase SRM. In the torque control method for a high-speed SRM, a positive torque (T*mA) of an active phase (A phase) of the two phases of the SRM is compensated for based on a negative torque attributable to an inactive phase (B phase) of two phases during a compensation control enable interval (ENA) ranging from a time point at which the active phase (A phase) is turned on to a time point at which tail current of the inactive phase (B phase) remains. Accordingly, the present invention can remarkably reduce a torque ripple occurring in high-speed operation mode in consideration of the influence of a negative torque attributable to tail current.

Abstract: The invention relates to a method for absorbing the displacement, under the influence of an external force, of at least one plunger (10,20) in a linear electrodynamic motor comprising a least an induction coil (11, 21) magnetically coupled with the plunger. Said method comprises the steps of: detecting in said induction coil a current induced (I?ind) amplified relative to the induced current. The invention can be applied to cryogenic machines on board space ships.

Abstract: An electric power supply system has a power bus for providing DC power, and a control unit for a source of power to supply the power bus. The power unit includes a damping algorithm to provide damping to power supplied on the power bus. A motor and a motor control include a compensation block for tapping power from the bus, and identifying a portion of a supplied signal due to the damping. The compensation block provides a signal to a summing block that addresses the damping on the power bus prior to the power being supplied to the motor. A method of utilizing such a system is also disclosed.

Abstract: A control technology for a synchronous motor for suppressing rotational pulsation caused by variation in individuals without making a control algorithm complex is provided. In a motor drive system which is a control device for a synchronous motor, in order to suppress the pulsation component of N times as high as the AC frequency for driving the synchronous motor, a controller in which the phase property of the disturbance response of the controller with respect to the pulsation frequency is within ±45° is arranged. Therefore, the torque pulsation component generated from distortion in induction voltage or variation between phases is suppressed.

Abstract: Methods and apparatus are provided for startup of a permanent magnet alternating current (AC) motor. The method comprises the steps of detecting startup of the permanent magnet AC motor; detecting a mechanical oscillation of the permanent magnet AC motor when startup of the permanent magnet AC motor is detected; and, in response to detection of the mechanical oscillation of the permanent magnet AC motor when startup is detected, suppressing the mechanical oscillation of the permanent magnet AC motor.

Abstract: A motor control device includes a measurement unit, a speed control unit, a correction unit, a drive unit, and a disturbance suppressing unit. During a time period before a measurement value of speed of one of a motor and a driven object which is driven by the motor measured by the measurement unit becomes greater than zero the correction unit corrects a manipulated variable such that a reduced correction amount which is from zero percent to less than 100 percent of a correction amount determined by the disturbance suppressing unit, is added to the manipulated variable determined by the speed control unit corresponding to a target speed of the one of the motor and the driven object.

Abstract: A computing unit simulates an ideal operation of a vibration excitation actuator by using at least a model operation parameter and the vibration-excitation movable mass data and calculates a parameter corresponding to acceleration/deceleration thrust for moving the vibration-excitation movable mass. A vibration isolation controller determines a control content of a vibration isolation driving unit based on the parameter corresponding to the acceleration/deceleration thrust and controls an operation of the vibration isolation driving unit so that a force canceling a reaction force, which acts on an apparatus when a vibration-excitation movable mass is moved, acts on the apparatus by moving the vibration isolation movable unit.

Abstract: The present invention provides a superconductive rotating electric machine drive control system that has higher efficiency and is smaller size and lighter in weight than conventional systems, and also provides a superconductive rotating electric machine drive control method to be implemented in the superconductive rotating electric machine drive control system. By the superconductive rotating electric machine drive control system and the superconductive rotating electric machine drive control method in accordance with the present invention, a control operation is performed so that the field current If2 applied to the superconductive field winding of the synchronous rotating electric machine satisfies an equation for the field current If2 in accordance with the variation of the electric power exchanged between the synchronous rotating electric machine and the power unit.

Abstract: A motor control device includes a current detecting unit detecting current flowing into a motor winding, a speed/electrical angle estimating unit estimating a rotational speed and an electrical angle of the motor, based on the current, a load torque estimating unit estimating load torque to be developed by a load, from a torque current obtained based on the current and the electrical angle, a motor constant and inertia moment of the motor inclusive of the load, a load torque phase calculating unit calculating a phase of periodic fluctuation indicated by the load torque, a torque-compensating current determining unit determining a sinusoidal torque-compensating current, based on the load torque phase, and an amplitude/phase adjusting unit detecting speed fluctuation of the motor to adjust amplitude and phase of the torque compensating current by increasing or decreasing the amplitude and the phase so that the speed fluctuation is reduced.

Abstract: A method and an apparatus for damping voltage oscillation of a voltage intermediate circuit of a frequency converter, the frequency converter comprising a half controlled rectifier bridge coupled to a supply network. The method comprises determining magnitude (Uc) of voltage of the voltage intermediate circuit, determining magnitude (Uin) of rectified voltage of the supply network, forming a derivative of a difference (Uin?Uc) between the rectified voltage of the supply network and the voltage of the voltage intermediate circuit, delaying firing of controllable components of the rectifier bridge on the basis of the formed derivative.

Abstract: Methods and apparatus are provided for startup of a permanent magnet alternating current (AC) motor. The method comprises the steps of detecting startup of the permanent magnet AC motor; detecting a mechanical oscillation of the permanent magnet AC motor when startup of the permanent magnet AC motor is detected; and, in response to detection of the mechanical oscillation of the permanent magnet AC motor when startup is detected, suppressing the mechanical oscillation of the permanent magnet AC motor.

Abstract: A control technology for a synchronous motor for suppressing rotational pulsation caused by variation in individuals without making a control algorithm complex is provided. In a motor drive system which is a control device for a synchronous motor, in order to suppress the pulsation component of N times as high as the AC frequency for driving the synchronous motor, a controller in which the phase property of the disturbance response of the controller with respect to the pulsation frequency is within ±45° is arranged. Therefore, the torque pulsation component generated from distortion in induction voltage or variation between phases is suppressed.

Abstract: A system and method for controlling an AC motor drive includes a control system programmed with an energy algorithm configured to optimize operation of the motor drive. Specifically, the control system receives input of an initial voltage-frequency command to the AC motor drive, receives a real-time output of the AC motor drive generated according to the initial voltage-frequency command, and determines a real-time value of a motor parameter based on the real-time output of the AC motor drive. The control system also inputs a plurality of modified voltage-frequency commands to the AC motor drive, determines the real-time value of the motor parameter corresponding to each of the plurality of modified voltage-frequency commands, and identifies an optimal value of the motor parameter based on the real-time values of the motor parameter.

Abstract: A neutron chopper according to the present invention includes a housing which internally forms a sealed space, the housing having window portions through which neutrons pass, a fixed shaft which is fixed inside the housing, a rotor which is rotatably supported by the fixed shaft, the rotor provided with a blocking portion which can block neutrons passing through the housing, and a motor which is provided inside the housing for rotating the rotor of the neutron chopper, where a stator of the motor is fixed to the fixed shaft, and a rotor of the motor receives a rotating force from the stator around the fixed shaft, and is fixed to the rotor of the neutron chopper. The neutron chopper is formed with small size, and neutron guides are easily disposed closely, consequently vacuum leak is hardly occurred in the neutron chopper.

Abstract: A motor control device includes a measurement unit, a speed control unit, a correction unit, a drive unit, and a disturbance suppressing unit. During a time period before a measurement value of speed of one of a motor and a driven object which is driven by the motor measured by the measurement unit becomes greater than zero the correction unit corrects a manipulated variable such that a reduced correction amount which is from zero percent to less than 100 percent of a correction amount determined by the disturbance suppressing unit, is added to the manipulated variable determined by the speed control unit corresponding to a target speed of the one of the motor and the driven object.

Abstract: There is provided a vector control device for an alternating-current electric motor having a damping controller which automatically calculates an optimum damping operation amount and does not require any gain setting itself, whereby an adjustment work of a control system can be simplified. The vector control device is equipped with a vector controller 30 for executing vector control on the alternating-current electric motor 6 in accordance with a current command or a torque command, and a damping controller 40 for calculating a damping operation amount for suppressing variation of a capacitor voltage Efc.

Abstract: A controller employed in conjunction with a synchronous generator monitors the output voltage of the generator. The controller employs the monitored output voltage as feedback that is used to control the excitation provided to an exciter field winding. In addition, the controller applies a control loop to the monitored output voltage that detects and modifies voltage ripple signals within the monitored output voltage to generate a compensated signal that is used to control the excitation to the exciter field winding. In particular, by detecting and modifying voltage ripple signals within the monitored output voltage, the controller is able to counteract armature reaction voltage ripples caused by unbalanced short-circuit faults, thereby preventing the build-up of voltage on the DC link.

Abstract: A control system and associated methods for an air treatment system. In one aspect, the present invention provides a control system and method for controlling blower speed as a function of separately determined smoke and dust concentrations. In one embodiment, the control system and method provides a variable delayed between changes in motor speed to address undesirable rapid changes between speeds. In another aspect, the present invention provides a system and method for calibrating a sensor to provide more uniform operation over time. In yet another aspect, the present invention provide a system and method for calibrating motor speed to provide more consistent and uniform motor speed over time. The present invention also provides a system and method for tracking filter life by as a function of time, motor speed and/or a sensed variable, such as particulate concentration in the environment.

Abstract: The invention indicates a correct one of multiple rotor positions. For example, the invention can determine, in a PM machine, which of two possible positions a rotor is in when the position is known only within ±? radians. If the actual rotor position is known to be one of ? and ?+?, for example as indicated by a resolver, the proposed invention can be used to determine whether the actual position is ? or ?+?.

Abstract: There is provided an electromechanical machine control system for variable speed controlling an electromechanical machine which can realize a desired control response and a stable control system by online regulating the gain of a linear differential controller by current feedback based on an electric parameter or mechanical parameter of the electromechanical machine. The electromechanical machine control system includes a current coordinate transformer (15) for coordinate transforming a current detection value of the electromechanical machine (13) which is inputted into a ?-axis current having the same phase as a position reference and a ?-axis current which advances 90 degrees further than the position reference, a ?-axis stabilizer (16) for implementing a linear differential control on the ?-axis current which is inputted to output a ?-axis current voltage correction amount and a ?-axis stabilizing gain regulator (17) for regulating the linear differential control gain of the ?-axis stabilizer.

Abstract: A generator control unit (GCU) provides active damping of a synchronous generator by monitoring the speed of the synchronous generator and detecting oscillations in the monitored speed. The oscillations are indicative of torsional oscillations within the mechanical drivetrain including the synchronous generator or generators. In response to detected oscillations in the monitored speed, the GCU generates a varying set-point value that is used to control the excitation voltage provided to the synchronous generator. Varying the excitation voltage provided to the synchronous generator causes a variation in synchronous generator torque. By selectively varying the torque in the synchronous generator, the GCU provides active damping in the synchronous generator that decreases or dampens the torsional oscillations.

Abstract: Motors comprising stators and rotors having a plurality of north poles and south poles and methods of controlling the same. A first sensor and a second sensor are provided. The first and second sensors are disposed on the stator in a manner that the first and second sensors never simultaneously detect boundaries between the north and south poles during rotation of the rotor. If any one of the first and second sensors continuously detects a north pole or a south pole for a predetermined duration, the motor is shut off.

Abstract: A switched reluctance drive is supplied from a power source. The phases of the machine are controlled by a current controller which uses an excitation strategy to minimize the supply current drawn for a particular output. The strategy alternates the excitation between two phases for a given time until the rotor moves to a desired position. A method of starting a switched reluctance motor having a stator with at least two phases, a moveable part, and a position transducer includes determining from transducer output a plurality of phases that are available to produce force in a desired direction, energizing a first phase of the available phases for a predetermined time period that is independent of the transducer output, and energizing a second phase of the available phases after energization of the first phase is initiated.

Abstract: A motor controller having a damper that dampens resonance in a motor drive of a common mode filter to prevent it from becoming over excited by operation of the motor drive at a resonant frequency of the common mode filter. The damper is connected to an output feeder line of a motor drive in the motor controller and provides a common mode path to ground for the common mode filter. Thus, even if the motor drive is operating at a resonant frequency of the common mode filter, the resulting resonance in the common mode filter is attenuated by rather than amplified by the common mode filter, thereby preventing the common mode filter from excessive excitation.

Abstract: While a rotor 4 of a permanent-magnet rotary machine 1 is rotating and an armature current thereof is substantially zero, a motor controller 2 performs a dq vector control process to control the permanent-magnet rotary machine 1 in a dq coordinate system which has a d-axis representing the direction of a magnetic field of the rotor 4 and a q-axis representing a direction perpendicular to the d-axis, and determines a magnetic pole position correcting quantity ?ofs to correct a magnetic pole position ?act detected by a magnetic pole position detector 8 so that a d-axis voltage command value Vdc determined by the dq vector control process will be substantially zero. The motor controller 2 controls the phases of armature voltages Vuc, Vvc, Vwc with magnetic pole positions corrected by the magnetic pole position correcting quantity ?ofs.

Abstract: An apparatus is described which reduces a time delay and a resultant phase shift in a gyroscope motor drive signal. The motor drive signal originates from a numerically controlled oscillator whose output is sampled at a predetermined rate. The apparatus includes a first element which upsamples the oscillator output signal samples and a band pass filter configured to receive an output from the first element and remove spectral components from the output of the first element. The apparatus further includes a third element which generates a tuning parameter, ??o, for tuning of the band pass filter and a scaling multiplier configured to normalize an output of the filter.

Abstract: There are performed converting electric currents Iu, Iv, and Iw flowing through the synchronous motor into a d-axis actual current Idfb and a q-axis actual current Iqfb on rotational coordinate axes which rotate synchronously with a rotor magnetic flux vector, on the basis of an actual position ? of the rotor of the synchronous motor; estimating a d-axis simulated current Idob and a q-axis simulated current Iqob on the basis of the d-axis actual current Idfb, the q-axis actual current Iqfb, a d-axis actual voltage command Vdref, and a q-axis actual voltage command Vqref; generating a d-axis actual voltage command Vdref and a q-axis actual voltage command Vqref on the basis of a d-axis current command Idref, a q-axis current command Iqref, a d-axis simulated current Idob, and a q-axis simulated current Iqob; and converting the d-axis actual voltage command Vdref and the q-axis actual voltage command Vqref into actual voltage commands Vuref, Vvref, and Vwref on the basis of the actual position ? of a rotor of t

Abstract: A variable motor (1) having reduced audible noise. This advantage is achieved by reducing or eliminating ripple torque by making the individual phase torques follow a certain profile, so that when the torques are summed, they are substantially constant. Therefore, the motor (1) back EMF is used as a reference waveform to control the winding currents to achieve reduced ripple torque. The back EMF reference is amplified and provided to the motor windings, and may be derived in a number of ways including use of sense windings, electronic derivation, and approximation by sensing the voltage applied to the windings.

Abstract: A multi-axes industrial processing machine with a multi-axes electrical drive system and at least two axle drives that have each an axle module and a built-in motor is disclosed. The machine further includes an impedance that is transformer-coupled with a supply module through an annular core. Either the phase lines on the AC side of the supply module or the output lines of the DC side of the supply module as well as an additional winding are wound on the annular core. The impedance is connected in parallel to the additional winding.

Abstract: A system and method for damping of resonant peaks in an electric motor which is operated using a converter with an intermediate voltage circuit, by means of a matched impedance to ground at the motor star point, and a corresponding electric motor is disclosed. In a converter system having an intermediate voltage circuit which operates with a mains system input inductor in the step-up converter mode or has other input-side inductances, there is a risk of natural system oscillations being formed via discharge capacitances in conjunction with motors. If the motor now has an amplitude/frequency response with a pronounced resonant frequency in the region of such natural system oscillations, then there is a risk of higher voltages occurring at the motor star point than in the motor phases.

Abstract: In a converter system having an intermediate voltage circuit which operates with a supply network-side input inductor in the step-converter mode or has other input-side inductances, there is a risk of natural system oscillations being formed via discharge capacitances in conjunction with motors. If the motor now has an amplitude/frequency response with a pronounced resonant frequency in the region of such natural system oscillations, then there is a risk of higher voltages occurring at the motor star point (S) than in the motor phases (I, V, W). This is prevented by the present invention by introducing an impedance (Z), in particular at the input to the motor, in order to damp capacitive discharge currents to ground potential, which are caused by system oscillations (fsys) (excited asymmetrically with respect to ground in the motor phases (U, V, W)) of the converter system (LK, UR, LT, M) in the winding sections.

Abstract: A controller for an electronically commutated electrical machine receives a feedback signal indicative of a parameter which it is desired to minimize, e.g. torque ripple, current, voltage, vibration or acoustic noise. The controller computes the amplitude and phase of a set of harmonics in the parameter and sequentially injects harmonics of the correct amplitude and phase to minimize the parameter. An optimizing routine iterates through the set of harmonics to further reduce the parameter.

Abstract: A synchronous motor control system includes a synchronous motor 1, an inverter 3 and a controller 4 wherein a current differential detecting unit 13 detects a variation of a motor current when the three phases of the motor 1 is short circuited by the inverter 3, namely at the moment when a carrier wave in a PWM signal generator 9 assumes maximum or minimum value, in a calculating unit 14 a phase &ggr; from &agr; axis of a stationary coordinate system to a three phase short circuited current differential vector is calculated, a phase &dgr; is estimated from d axis to the three phase short circuited current differential vector by making use of d axis current id and q axis current iq on d-q axes coordinate system in the controller 4, thereafter the magnetic pole position &thgr; with respect to &agr; axis is calculated from the phases &ggr; and &dgr;, based on thus calculated magnetic pole position &thgr;, d-q axes control units 11, 7 and 8 are constituted to control the synchronous motor, thereby a highly reliab

Abstract: A switched reluctance machine uses a Hall-effect device to detect the flux in the flux path for each machine phase. The flux signal from the Hall-effect device is fed back to a controller which compares the flux feedback with a demand signal to produce an error signal. The error signal is used to control the machine flux using a control law function actuating timed switches for each phase.

Abstract: The invention relates to an electric drive device with a DC motor (2) comprising a control circuit with an electronic commutator (3). The invention is characterized in that a derivation of a control signal (V_i_ref) is obtained from an induced motor voltage (E_sample) detected by a measuring device and from a reference value (V_i_av) which serves to regulate the speed of the DC motor (2), and in that the derived control signal (V_i_ref) serves to achieve a substantially constant torque of the DC motor (2) through adjustment of the motor currents (ia, ib, ic).

Abstract: A synchronous motor control system includes a synchronous motor 1, an inverter 3 and a controller 4 wherein a current differential detecting unit 13 detects a variation of a motor current when the three phases of the motor 1 is short circuited by the inverter 3, namely at the moment when a carrier wave in a PWM signal generator 9 assumes maximum or minimum value, in a calculating unit 14 a phase &ggr; from &agr; axis of a stationary coordinate system to a three phase short circuited current differential vector is calculated, a phase &dgr; is estimated from d axis to the three phase short circuited current differential vector by making use of d axis current id and q axis current iq on d-q axes coordinate system in the controller 4, thereafter the magnetic pole position &thgr; with respect to &agr; axis is calculated from the phases &ggr; and &dgr;, based on thus calculated magnetic pole position &thgr;, d-q axes control units 11, 7 and 8 are constituted to control the synchronous motor, thereby a highly reliab

Abstract: A system for low acoustic noise spindle motor commutation is disclosed. The system contains a control device that generates commutation control signals which cause spindle motor drivers to source or sink current through windings of a spindle motor. The windings create electromagnetic fields which induce rotational movement in a spindle motor rotor. Low acoustic noise snubber devices are coupled to each winding and are dynamically configurable by the control device to provide low spindle motor driver charging current upon initial application of power to the spindle motor, and reduced acoustic noise and back EMF-generated current and voltage surges at the spindle motor driver during spindle motor commutation.

Abstract: A device which detects the angle of rotation of a rotor with respect to a stator of a brushless multi-phase d.c. motor. The rotor comprises a permanent magnet and the stator comprises a plurality of electrical windings. Electric drive signals are applied to the windings in order to drive the rotor. The device includes a drive circuit for applying pulse-shaped electric test signals to the windings while the rotor does not rotate. A measurement circuit detects flyback pulses generated by the motor in response to the test signals. A processing unit processes the durations of the detected flyback pulses in combination in order to determine the angle of rotation. On the basis of the angle of rotation thus determined, the motor can be started such that the rotor is set into rotation in a predetermined direction of rotation.