571results about "AC motor angular speed control" patented technology

A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference Δθ between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position. A high-efficiency motor drive unit with improved maintainability of rotary sensor and improved accuracy of sensing the magnet pole position of a permanent magnet synchronous motor that accelerates and decelerates very quickly in a wide range of speed is realized.

A control method for a motor that rotates based on flux linkages to a winding member of the motor when the winding member is energized by a drive current is provided. The method includes storing magnetic-state information indicative of a relationship between each of a plurality of predetermined operating points of the drive current and a magnetic-state parameter associated with the flux linkages. The method includes obtaining at least one of command information associated with an operating state of the motor and detection information associated with the operating state of the motor. The method includes referencing the magnetic-state information with the use of the obtained at least one of the command information and detection information to obtain a value of the magnetic-state parameter based on a result of the reference. The method includes controlling an output of the motor based on the obtained value of the magnetic-state parameter.

A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference Δθ between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position.

To estimate an initial magnetic pole position in a short time, estimated axes for control that correspond to the d-axis and the q-axis are set as the γ-axis and the d-axis, and a high frequency rotation voltage or alternating voltage on the γδ coordinate system is applied to the motor. A high frequency current ih that flows in the motor due to the application of the high frequency voltage is extracted from a detected motor current (armature current) and a direct current component (ihγ×ihd)DC of a product of the γ-axis and d-axis components of the high frequency current ih is derived. On the other hand, the γ′-axis component ichγ and the δ′-axis component ichd of the high frequency current ih that are shifted by p / 4 in electric angle from the γ-axis and the d-axis are obtained and a direct current component of their product (ichγ×ichd)DC is obtained. Thereafter, the magnetic pole position is estimated by computing the axial error Δθ between the γ-d axes utilizing the two direct current components.

A synchronous motor drive system in accordance with the present invention detects a DC current of an inverter which drives a synchronous motor, and based on the magnitude of the current, estimates torque current components that flow through the motor, and then based on the estimated value, determines the voltage which is applied to the motor, and finally estimates and computes the magnetic pole axis located inside the motor using the estimated value of the torque current.

A constant detecting apparatus 15 comprising a detecting unit 26 and a calculating unit 27. The detecting unit 26 is structured comprising a rotation sensor 41, a torque sensor 42, a position sensor 43, a rotor temperature sensor 44, a winding temperature sensor 45, a phase voltage detector 46, and phase current detectors 47 and 47. The calculating unit 27 calculates the induced voltage constant Ke that changes depending on the motor temperature Tmag while the motor 11 is being driven based on each of the detected signals from the detecting unit 26, and at the same time, the d axis current Id and the q axis current Iq are calculated after elimination of the iron loss, and the d axis inductance Ld and the q axis inductance Lq in the actual operating state of the motor 11 are calculated.

A synchronous motor drive system in accordance with the present invention detects a DC current of an inverter which drives a synchronous motor, and based on the magnitude of the current, estimates torque current components that flow through the motor, and then based on the estimated value, determines the voltage which is applied to the motor, and finally estimates and computes the magnetic pole axis located inside the motor using the estimated value of the torque current.

After the rotor position has been fixed prior to the start of a motor, the driving mode can be rapidly switched to sensorless driving and the motor can be started and controlled, by conducting current conversions in such a power supply pattern that increases the starting output torque of the motor, and controlling the inverter output voltage.

An electric power steering apparatus includes: a rotation speed detecting unit which detects a rotation speed of the electric motor; a compensation current determining unit which determines an instruction value of a compensation current to flow through the electric motor to suppress torque ripples due to distortion of an induced electromotive force waveform of the electric motor in accordance with a load correspondence quantity as a physical quantity corresponding to a load of the electric motor and the rotation speed detected by the rotation speed detecting unit; a correcting unit which corrects the current target value on the basis of the compensation current instruction value; and a control unit which performs a feedback control on the electric motor so that a current having the current target value as corrected by the correcting unit flows through the electric motor.

An inverter for a washer performing drive control of an electric motor imparting a rotational driving force required for washing, rinsing and dehydrating operations in a full automatic washer performing the washing, rinsing and dehydrating processes continuously. The inverter comprises a control means for operating the motor with a full field in the low speed rotational region of washing, rinsing and dehydrating operations, with weak field in the high speed rotational region of dehydrating operation, and performing vector control of the output of the motor in the case of full field operation, and voltage / phase control of the motor in the case of field weakening operation.

The motor control device includes a current detecting portion for detecting a phase current that flows in an armature winding of a stator of a three-phase motor based on current that flows between an inverter for driving the motor and a DC power supply. The motor control device performs a position sensorless vector control for the motor based on a control current that is obtained by a three-phase to two-phase conversion of the phase current based on an estimated rotor position of the motor. The motor control device farther includes a superposing portion for superposing a superposed voltage having a predetermined frequency on a drive voltage for driving the motor and an estimating portion for deriving the estimated rotor position based on the superposed current that is extracted from the control current and flows in the motor in accordance with the superposed voltage. A voltage vector locus of the superposed voltage from the superposing portion presents an ellipse.

Axial error calculation unit is provided for estimating an axial error DELTAtheta between a d-q axis and a dc-qc axis by using Ld, Lq, Ke, Id*, Iq*, Idc and Iqc in a range of all rotational speeds except zero of a rotational speed command of a synchronous motor, Ld denoting an inductance on a magnetic pole axis d of the synchronous motor, Lq an inductance on a q axis orthogonal to the magnetic pole axis d, Ke a generated power constant of the motor, Id* a current command of the d axis, Iq* a current command on a q axis, Idc a detected current value on an assumed dc axis on control, and Iqc a detected current value on an assumed qc axis orthogonal to the assumed dc axis. Irrespective of presence of saliency, position sensorless control can be achieved in a wide range a low to high speed zone.

In order to provide a driving device for a motor having a capability equivalent to conventional vector control type sensorless method by simplifying the controls structure to reduce number of parts to be adjusted, and to stabilize the control system, a driving device for a synchronous motor does not include a speed controller or a current controller, and calculates a voltage impressed on a motor on coordinate axes (dc / qc axes) based on a magnetic pole axis. For calculating a voltage command, command values such as a rotation speed command and a current command are used, and Iq* corresponding to a torque current command is calculated and provided based on a detected current value.

Axial error calculation unit is provided for estimating an axial error DELTAtheta between a d-q axis and a dc-qc axis by using Ld, Lq, Ke, Id*, Iq*, Idc and Iqc in a range of all rotational speeds except zero of a rotational speed command of a synchronous motor, Ld denoting an inductance on a magnetic pole axis d of the synchronous motor, Lq an inductance on a q axis orthogonal to the magnetic pole axis d, Ke a generated power constant of the motor, Id* a current command of the d axis, Iq* a current command on a q axis, Idc a detected current value on an assumed dc axis on control, and Iqc a detected current value on an assumed qc axis orthogonal to the assumed dc axis. Irrespective of presence of saliency, position sensorless control can be achieved in a wide range a low to high speed zone.

The motor control device includes a current detecting portion for detecting a phase current that flows in an armature winding of a stator of a three-phase motor based on current that flows between an inverter for driving the motor and a DC power supply. The motor control device performs a position sensorless vector control for the motor based on a control current that is obtained by a three-phase to two-phase conversion of the phase current based on an estimated rotor position of the motor. The motor control device farther includes a superposing portion for superposing a superposed voltage having a predetermined frequency on a drive voltage for driving the motor and an estimating portion for deriving the estimated rotor position based on the superposed current that is extracted from the control current and flows in the motor in accordance with the superposed voltage. A voltage vector locus of the superposed voltage from the superposing portion presents an ellipse.

A motor control apparatus comprises a fundamental wave current control system that controls a fundamental wave component of a motor current in an orthogonal coordinate system which rotates in synchronization with a rotation of a 3-phase AC motor, a higher harmonic current control system that controls a higher harmonic component contained in the motor current in an orthogonal coordinate system rotating with a frequency which is an integral multiple of the frequency of the fundamental wave component of the motor current, a voltage command value generating device that generates 3-phase AC voltage command values by adding an output from the fundamental wave current control system and an output from the higher harmonic current control system, a power conversion device that converts a DC source voltage to a 3-phase AC voltage corresponding to the 3-phase AC voltage command values and outputs the 3-phase AC voltage to the 3-phase AC motor, a voltage saturation detection device which detects that an output voltage from the power conversion device is in a saturated state and a gain adjustment device that reduces a current control gain for the higher harmonic current control system if the voltage saturation detection device detects that an output voltage is in a saturated state.

A synchronous machine control apparatus which can produce a torque level as close as possible to a desired torque command level while considering limitations on an output current of a power conversion unit. A synchronous machine control apparatus includes a torque current command generator including a torque current calculator for calculating a torque current command iδ** from a torque command τ* and a flux command φ*, a torque current limit generator for generating a maximum torque current command value iδ*max that can be generated based on a magnetizing current command iγ* and a current limit value imax, and a limiter for imposing limitations on iγ** based on iγ*max, a flux command generator for calculating the flux command φ* based on iγ* fed from the torque current command generator, a flux calculator for calculating an interlinked armature flux feedback value |Φ| based on an armature current feedback value, and a flux controller for generating the magnetizing current command iγ* such that φ* and |Φ| coincide with each other and delivering iγ* to the torque current command generator.

A motor magnetic-pole-position estimating apparatus includes a command voltage output device and a current detector. A model-current calculator is configured to calculate a model current corresponding to a voltage equation for a predetermined model of a motor based on a command voltage and an actual current. A current-difference calculator is configured to calculate a current difference between the model current and the actual current. Each of first and second magnetic-pole-position-difference calculators is configured to calculate a magnetic-pole-position difference between an actual magnetic-pole position of the motor and an estimated or designated magnetic-pole position based on the current difference depending on whether or not a rotation speed of the motor is lower than a predetermined value. A magnetic-pole-position calculation device is configured to calculate the magnetic-pole position of the motor based on the magnetic-pole-position difference calculated by the first or second magnetic-pole-position-difference calculator.

An inverter control device includes a phase current detection unit which is connected to a current sensor. The current sensor detects current flowing between a three-phase inverter which converts a DC voltage into AC three-phase voltages and a DC power supply which outputs the DC voltage, and the phase current detection unit detects phase current flowing in each phase of the inverter from a result of detection by the current sensor, so as to control the inverter on the basis of a result of detection by the phase current detection unit. The phase current detection unit includes an estimation block which estimates phase current of an intermediate voltage phase or current corresponding to the phase current of the intermediate voltage phase as a first estimated current, and estimates phase current of a maximum voltage phase or phase current of a minimum voltage phase using the first estimated current so that each phase current can be detected.

A permanent magnet rotating electrical machine capable of conducting a variable speed operation at high output in a wide range from low speed to high speed and improving efficiency and reliability in a wide operating range. Two kinds of permanent magnets having different shapes or different magnetic characteristics are embedded in a rotor core, to form a magnetic pole. The permanent magnets arranged at the magnetic pole include a permanent magnet whose product of coercive force and thickness along a magnetizing direction is small and the permanent magnet whose product of coercive force and thickness along the magnetizing direction is large. A magnetic field created by passing a current to an armature coil for a short time is used to irreversibly magnetize the permanent magnet whose product of coercive force and thickness along magnetizing direction is small, thereby changing a total linkage flux amount, and a positive d-axis current is passed when torque is large.

Let the rotating axis whose direction coincides with the direction of the current vector that achieves maximum torque control be called the qm-axis, and the rotating axis perpendicular to the qm-axis be called the dm-axis. A motor control device switches its operation between low-speed sensorless control and high-speed sensorless control according to the rotation speed of the rotor. In low-speed sensorless control, the magnetic salient pole of the motor is exploited, and the d-q axes are estimated by, for example, injection of a high-frequency rotating voltage. In high-speed sensorless control, the dm-qm axes are estimated based on, for example, the induction voltage produced by the rotation of the rotor. During high-speed sensorless control, the γ(dm)-axis current is kept at zero irrespective of the δ(qm)-axis current.

A control method for a motor that rotates based on flux linkages to a winding member of the motor when the winding member is energized by a drive current is provided. The method includes storing magnetic-state information indicative of a relationship between each of a plurality of predetermined operating points of the drive current and a magnetic-state parameter associated with the flux linkages. The method includes obtaining at least one of command information associated with an operating state of the motor and detection information associated with the operating state of the motor. The method includes referencing the magnetic-state information with the use of the obtained at least one of the command information and detection information to obtain a value of the magnetic-state parameter based on a result of the reference. The method includes controlling an output of the motor based on the obtained value of the magnetic-state parameter.

In a case where a computing period of a torque ripple compensation section which computes current compensation values Δid and Δiq to be caused to flow into a motor in order to prevent occurrence of a torque ripple in the motor differs from a control period of a current control section which controls a feedback to the motor in such a way that current command values i*d and i*q additionally provided with the current compensation values Δid and Δiq flow into the motor, the microcomputer sets the current compensation values Δid and Δiq to zero when a rotor angular velocity ωre of the motor is equal to or greater than a first threshold value ω1.

A motor control device includes an estimator for estimating a rotor position of a motor having a salient pole by using a value corresponding to a q-axis inductance of the motor as an operation parameter where an estimated axes for the control corresponding to d-q axes are γ-δ axes, and a controller for controlling the motor based on the estimated rotor position. The estimator generates a deviation between a d-axis and a γ-axis by performing the estimation of the rotor position based on a value between a real q-axis inductance and a real d-axis inductance of the motor adopted as the operation parameter. The controller controls the motor so that a γ-axis component of a motor current supplied to the motor is maintained to be a predetermined value of zero or close to zero regardless of a value of a δ-axis component of the motor current.