6055results about "Electric motor control" patented technology

Amperage control of a power tool motor is provided by pulse width modulation of current from a power supply. The pulse width modulation may be varied according to the determined motor current and measured power supply voltage. The power supply preferably includes a battery, such a lithium ion or nickel cadmium.

A system and method for powered surgical handpiece capable of powering various micro-cutting instruments is described. The system is comprised of a controller adapted for controlling/interfacing with a powered surgical handpiece based upon user-defined procedural information. A data entry device is used for entering the user-defined procedural information used by the controller for configuring and operating the motor control system.

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 motor control system for a brushless and sensorless DC motor for driving a compressor, pump or other application, includes a protection and fault detection circuit for detecting a locked rotor and a rotor which has stopped because of lost rotor phase lock. The motor control system also includes an off-the-shelf motor control integrated circuit having an input for disabling power outputs to the motor phase coils. The protection and fault detection circuit uses a back EMF sampling circuit coupled to the motor phase coils and momentarily disables power to the motor phase coils, via the motor control integrated circuit input, to determine if the motor rotor is rotating. The system also monitors supply voltage, supply current, temperature, and motor speed limits to detect faults and protect system components.

Corresponding to a target torque, the control device calculates a target value of a feature based on at least one of the length of a long axis of a current vector locus and the length of the short axis and further superimposes a superimposed current on a drive current for the motor, the superimposed current having a frequency different from the frequency of the drive current. Further, the control device detects an actual value of the feature based on at least one of the length of a long axis of a current vector locus of the superimposed current and the length of the short axis of the same and finally detects a phase angle of the motor based on the target value and the actual value for the feature. The manipulation of a detecting phase is performed by feedback of a feature obtained by the magnitude of the superimposed current. That is, when the actual feature is more than the target value, the detecting phase is advanced. Conversely, when the actual feature is less than the target value, the detecting phase is delayed.

The invention discloses a method for improving the estimation accuracy of the rotor position of a permanent magnet synchronous motor. The method comprises the following steps: on the basis of realizing estimation of the rotor position of the permanent magnet synchronous motor by utilizing a pulse-shake high frequency voltage injection method, processing the extracted position estimation error function, eliminating a second harmonic component introduced due to asymmetric motor parameters, so as to obtain a processed position estimation error function, then establishing a phase-locked loop, and adjusting the phase-locked loop to be 0, thus obtaining estimated rotor speed and estimated rotor position. The method disclosed by the invention can effectively inhibit position estimation second harmonic error caused by the asymmetric motor parameters, and the performance of a control system without a position sensor can be improved.

A variable speed wind turbine having a doubly fed induction generator (DFIG), includes an exciter machine mechanically coupled to the DFIG and a power converter placed between a rotor of the DFIG and the exciter machine. Thus, the power converter is not directly connected to the grid avoiding the introduction of undesired harmonic distortion and achieving a better power quality fed into the utility grid. Moreover, the variable speed wind turbine includes a power control and a pitch regulation.

Methods and apparatus for controlling a polyphase motor in implantable medical device applications are provided. In one embodiment, the polyphase motor is a brushless DC motor. The back emf of a selected phase of the motor is sampled while a drive voltage of the selected phase is substantially zero. Various embodiments utilize sinusoidal or trapezoidal drive voltages. The sampled back emf provides an error signal indicative of the positional error of the rotor. In one embodiment, the sampled back emf is normalized with respect to a commanded angular velocity of the rotor to provide an error signal proportional only to the positional error of the motor rotor. The error signal is provided as feedback to control a frequency of the drive voltage. A speed control generates a speed control signal corresponding to a difference between a commanded angular velocity and an angular velocity inferred from the frequency of the drive voltage. The speed control signal is provided as feedback to control an amplitude of the drive voltage. In one embodiment, an apparatus includes a brushless DC motor and a commutation control. The commutation control provides a commutation control signal for a selected phase of the motor in accordance with a sampled back electromotive force (emf) of that phase. The back emf of the phase is sampled only while the corresponding drive voltage for the selected phase is substantially zero, wherein a frequency of a drive voltage of the motor is varied in accordance with the commutation control signal.

A disk drive is disclosed comprising a spindle motor comprising a plurality of windings for rotating a disk. The spindle motor is rotated by commutating the windings over a plurality of commutation states, wherein audible noise generated by the disk drive is reduced by phase modulating the commutation interval. Further audible noise reduction is achieved by modulating a current applied to the windings which substantially reduces discontinuities in the torque output of the spindle motor caused by phase modulation of the commutation intervals.

A disk drive is disclosed including a disk, a head coupled to a distal end of an actuator arm, and a voice coil motor (VCM) operable to rotate the actuator arm about a pivot to actuate the head radially over the disk, wherein the VCM comprises a coil. Control circuitry within the disk drive measures a load resistance of the coil prior to executing a load operation, wherein the load operation moves the actuator arm off a ramp to load the head onto the disk. The load resistance of the coil is then converted into an initial coil temperature estimate.

A control system for a motor including a rotor comprises a sensorless sensor module that includes a saliency-based estimator module that generates a first rotor position signal based on saliency and a back electromotive force (emf) estimator module that generates a second rotor position signal based on back emf. A selector selects the first rotor position signal for rotor speeds below a first rotor speed and the second rotor position signal for rotor speeds above the first rotor speed. A rotor position sensor senses a position of the rotor and generates a third rotor position signal. A fault detection module senses faults in the rotor position sensor and outputs the third rotor position signal when a fault is not detected and one of the first and second rotor position signals when the fault is detected. An indirect field oriented control (IFOC) system controls the motor based on a selected one of the first, second and third rotor position signals.

Apparatus are provided for motor control systems and related medical devices. In one embodiment, a control system includes a motor having a rotor, a modulation module coupled to the motor, and a control module coupled to the motor and the modulation module. The modulation module generates a modulated voltage that is applied to the motor, and the control module adjusts a duty cycle of the modulated voltage to achieve a commanded rotation of the rotor and detects a degradation condition based on the duty cycle.

An integrated torsional mode damping method for a current source converter, including a rectifier, an inverter, and a DC link inductor coupled between the rectifier and the inverter, includes sensing a signal representative of torque on a shaft coupled to the inverter or rectifier; using the sensed signal for detecting a presence of a torsional vibration on the shaft; and damping the torsional vibration by modulating active power through the respective inverter or rectifier.

A powered tool for performing surgical procedures. The tool includes a handpiece in which a power generating unit is housed. A control member is mounted to the handpiece. The control member is mounted to the handpiece so that the orientation of the control member can be selectively set relative to the point to which it is mounted to the handpiece and so it can move relative to a reference point on the handpiece. A control module monitors the orientation of the control member and its position relative to the reference point. Based on the control member orientation and position, the control module generates signals to regulate the operation of the power generating unit. When the power generating unit is a motor, the control module generates signals to ensure that the maximum speed at which the motor can be driven is less than the no load speed.

A surgical instrument includes a drive shaft, a motor for rotating the drive shaft, and a motor speed control. The motor speed control includes a first switch and a second switch which are in communication with the motor. The first switch is disposed over and in registration with the second switch. The first switch has an activated state such that the first switch sends a first signal to the motor. The motor rotates the drive shaft in response to the first signal. The second switch sends a second signal to the motor that varies the speed that the motor rotates the drive shaft in response to a force applied to the second switch by the first switch.

In an operation range of an actuator subjected to quick acceleration and deceleration, a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area. A controller comprises a voltage saturation detecting means for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

A door position control including an electric door actuator having a motor and a motor controller in communication with a system controller. A motor actuation operation is selected from a plurality of predetermined motor actuation operations to provide control signals to the motor controller for controlling actuation of the motor for control of door movement. Control of door movement is effected with reference to parameters specific to an installation location including an angular sweep of the door between open and closed positions and with reference to an available bus voltage for supplying power to the motor.

A current detection circuit (18) detects that a drive current of the stator coil (2d) is exceeding a threshold value Ir. A rotation number detection circuit (17) detects that the number of rotations of a rotor (2a) is lower than a threshold value Nr. A computing part (20) outputs a PWM signal which switches a semiconductor switching element (3a) of the inverter circuit part (3). The computing part (20) changes the threshold values Ir and Nr in accordance with the PWM duty of the PWM signal determined in accordance with a pressed distance of a switch trigger (7) and detects a locked state of the motor (2) on the conditions that the motor current I is exceeding the set threshold value Ir and that the number of rotations N thereof is lower than the threshold value Nr.

A system for operating a barrier system such as a garage door, gate or fence. A DC motor is connected to and operates a barrier drive. A power amplifier is configured to receive power signals from a power supply and to output modulated DC signals to the DC motor. A controller implements an intelligent closed-loop motion control algorithm to control the power amplifier according to a non-linear motion profile. A feedback sensor provides status signals to the controller to determine position or speed of the barrier.

A current controller for an electric machine that includes an input, an output, a threshold generator and a comparator. The threshold generator stores a scaling factor and includes a PWM module that operates on a reference voltage to generate a threshold voltage. The duty cycle of the PWM module is then defined by the scaling factor. The comparator compares a voltage at the input against the threshold voltage and causes an overcurrent signal to be generated at the output when the voltage at the input exceeds the threshold voltage.

A technique for configuring programmable, networked electrical components of a system includes downloading data into each component from a configurator, based upon a database for the system. The components include memory objects which are designed to store data descriptive of the system, the component, the component location in the system, and the component configuration. The configurator may load the information prior to, during or following assembly of the components in the system. The configurator may also modify system and component configurations following installation of the system by modifying the data downloaded into the individual components.

The invention concerns a system for active reduction of rotational nonuniformities of a shaft, especially the drive shaft (10) of an internal combustion engine or a shaft that is coupled or can be coupled to it, with at least one electric machine (4), which is coupled or can be coupled to the shaft, wherein the electric machine (4) is controlled such that it generates a rapidly varying torque, to reduce the rotational nonuniformities, and it superimposes on this torque a positive or negative torque in order to further achieve a driving action or braking or generator type action. The invention is also oriented to a corresponding method for active reduction of rotational nonuniformities.

A system and method for detecting failure of a cooling system in an alternating current machine, such as a motor and/or a generator. For example, in one embodiment energy wasting is initiated and a failure is indicated if a temperature rises by more than a selected amount over a selected time period.

There is provided an actuator control device for force-controlling a joint driving actuator according to a commanded joint force command value τ_a. The actuator control device includes a joint value detecting means for detecting a joint value q at an output stage of the actuator, an action force detecting means for detecting an action force τ_e in a joint driving direction at the output stage of the actuator, and a driving force determining means for determining an instructed driving force τ to the actuator, on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the joint force command value τ_a, the action force τ_e, and a joint value velocity obtained by time-differentiating the joint value q are given.

In a charge/discharge mode, an inverter performs power conversion between a power storage device and a commercial power supply electrically connected to a neutral point through a power line. In the charge/discharge mode, ECU sets a carrier frequency of the inverter to a frequency higher than in a running mode. Further, in the charge/discharge mode, a drive circuit drives the inverter using a gate resistance higher than in the running mode.

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.

The present invention provides a slip rate estimating device measuring a slip ratio without the need for a body speed and a slip ratio control device using the slip ratio estimating device. A motor torque measured by a torque measuring instrument is input to each of a vehicle model (601) and an SRE (602) that performs calculations including time differentiation of the slip ratio. The vehicle model (601) derives a wheel rotation speed, a wheel rotation acceleration, and a body speed. The vehicle model (601) outputs the wheel rotation speed and the wheel rotation acceleration to the SRE (602). The SRE (602) outputs the slip ratio based on the motor torque, the wheel rotation speed, and the wheel rotation acceleration.

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.

To provide a wind turbine generator, a wind turbine generator system, and a power-generation control method of a wind turbine generator that are capable of improving the power-generation capability and reducing the fatigue load on the windmill. A data accumulation unit 25 sequentially accumulates data sets of a generated output power P during operation of the wind turbine generator, an incoming wind speed Ws estimated on the basis of a wind speed measured at the anemometer, and a wind direction deviation, which is the difference between a wind direction θw measured at the anemoscope and the orientation of the nacelle; statistical analysis of the data accumulated is carried out by an analyzing unit 26; a distribution curve corresponding to the wind direction deviation of the generated output power at each incoming wind speed is determined; the wind direction deviation corresponding to the peak of the distribution curve is set as a correction value θd of the anemoscope; the correction value of the anemoscope for each incoming wind speed is stored in the wind-direction correction table 27; the wind direction Vw measured at the anemoscope is corrected with the correction value θd of the anemoscope for each incoming wind speed Ws; and power-generation control is carried out using the corrected wind direction as a control parameter.

Specific anomalies and details of failures as well as measures thereagainst are described that might possibly occur in electric power converters that drive and control permanent-magnet synchronous motors. An electric power converter capable of stable operation has a protective function of taking proper measures against such failures that might possibly occur.