Proportional-integral System Patents (Class 388/906)
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Patent number: 11681273Abstract: A method for event processing includes accepting for processing, as accepted events and according to a target rate limit, at least a subset of received events; associating respective ingested timestamps with the accepted events; associating respective processing completion timestamps with processed events of the accepted events; determining an average measured lag time using at least a subset of the respective processing completion timestamps and corresponding respective ingested timestamps; obtaining a throttled rate limit using a proportional-integral-derivative (PID) controller; and accepting subsequent events according to the throttled rate limit. The PID controller can be configured to use, as an input, an error value that is a difference between a target lag time and the average measured lag time. An integral part of the PID controller can be set to zero responsive to an accumulated average lag time being less than the target lag time.Type: GrantFiled: July 30, 2021Date of Patent: June 20, 2023Assignee: PagerDuty, Inc.Inventor: Taavi Andrew Burns
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Patent number: 11406949Abstract: An apparatus for agitation of fluids is described that comprises an agitation chamber, an impeller configured to have a motor, a shaft, and blades, and a plurality of baffles. Further, the plurality of baffles have a predetermined shape and configuration. Further, the plurality of baffles are placed on a side wall of the agitation chamber.Type: GrantFiled: December 15, 2018Date of Patent: August 9, 2022Inventor: Nakul Nakul
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Patent number: 8541972Abstract: Disclosed is a method for suppressing a speed ripple occurring during an operation of an AC motor by using a torque compensator based on an activation function. The method includes the steps of calculating a speed error ?err based on a reference speed ?ref and an actual speed ?act; calculating a controller output Trm by using the speed error ?err as an input of a PI control and an operation of a compensated torque Tcom; and determining a torque variation based on the controller output Trm and a reference torque Tref and operating the torque variation in relation to an anti-windup gain Ka to use torque variation as an input of an integral (I) control. The method suppresses the speed ripple by compensating for the torque ripple through a controller which calculates the compensated torque by taking the signs of the speed error and the differential speed error into consideration.Type: GrantFiled: December 8, 2011Date of Patent: September 24, 2013Assignee: Kyungsung University Industry Cooperation FoundationInventors: Dong Hee Lee, Jin Woo Ahn
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Patent number: 8018183Abstract: A speed controller used in a control loop of a motor includes a comparator, a processing device, and an arithmetic logical unit (ALU). The comparator compares a received instruction speed or a received measured speed of the motor with a predetermined speed value, outputs a first signal to the processing device when the received speed is greater than the predetermined speed value, or outputs a second signal to the processing device when the received speed is equal to or less than the predetermined speed value. The processing device receives a speed difference between the instruction speed and the measured speed. The processing device outputs a first proportional value when the first signal is received, or outputs a second proportional value when the second signal is received. The ALU outputs an instruction current to the control loop by calculating the proportional value according to a predetermined calculation rule.Type: GrantFiled: April 9, 2009Date of Patent: September 13, 2011Assignee: Foxnum Technology Co., Ltd.Inventors: Shih-Chang Chen, Shen-An Chen, Rong-Cong Hung, You-Ren Lin, Rong-Hwang Horng, Yaw-Shen Lai
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Patent number: 7812557Abstract: A motor controller includes an output voltage modulator that outputs sinusoidally-modulated voltage for driving a motor; a modulation factor specifier allowing specification of a modulation factor greater than 1.0 for the output voltage; a current detector that detects current flowing in the motor; and a field-oriented controller that divides the current detected by the current detector into a d-axis current component and a q-axis current component and that conforms each of the components to a command current produced based on a command rotational speed; a rotational position estimator that estimates motor rotational speed and rotor rotational position for use by the field-oriented controller; wherein the position estimator includes a filter that smoothes a d-axis induced voltage obtained during the estimation, and the motor rotational speed and the rotor rotational position are estimated based on the d-axis induced voltage smoothed by the filter.Type: GrantFiled: March 24, 2008Date of Patent: October 12, 2010Assignee: Kabushiki Kaisha ToshibaInventor: Sari Maekawa
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Patent number: 7446498Abstract: A method and apparatus perform control. A control method according to one embodiment accesses a Hall effect signal; obtains an error signal relating to a system parameter using the Hall effect signal and a reference signal for the system parameter; obtains a calculated signal for the system parameter using the error signal; and utilizes the calculated signal as a new reference signal for the system parameter, for a next iteration of the obtaining steps.Type: GrantFiled: September 22, 2006Date of Patent: November 4, 2008Assignee: Honeywell International Inc.Inventors: Louis Cheng, Ming Ma
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Patent number: 7433762Abstract: Methods for controlling at least two actuators are provided. An internal control system sends an input received from the main control system to a first actuator and diverts a portion of the input to a second actuator when an input constraint of the first actuator is reached. The actuators may be throttle valves for heating a hydraulic line. The internal control system includes a cutoff rerouter for implementing the sending and the diverting of the input and an adaptive cutoff controller, e.g., an integral controller, for determining the input constraint of the first actuator.Type: GrantFiled: February 8, 2005Date of Patent: October 7, 2008Assignee: Halliburton Energy Services, Inc.Inventor: Jason D. Dykstra
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Patent number: 7414379Abstract: A servo control system having a proportional (P) or a proportional plus integral (PI) position controller, which output signal represents an input speed reference signal for a speed close loop system with a speed controller detecting a speed deviation, derived from a speed feedback loop, which output signal represents an input current reference signal for a current close loop system with a current controller detecting a current deviation, derived from a current feedback loop, which controls an amount of the current flowing through a motor.Type: GrantFiled: October 12, 2006Date of Patent: August 19, 2008Assignee: Cambridge Technology, Inc.Inventor: Vladimir I. Oks
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Patent number: 7392113Abstract: Methods, control systems, and information handling systems for controlling at least two actuators are provided. An internal control system sends an input received from the main control system to a first actuator and diverts a portion of the input to a second actuator when an input constraint of the first actuator is reached. The actuators may be throttle valves for heating a hydraulic line. The internal control system includes a cutoff rerouter for implementing the sending and the diverting of the input and an adaptive cutoff controller, e.g., an integral controller, for determining the input constraint of the first actuator. The information handling systems include a determination logic for determining if an input received from the main control system is greater than an input constraint of the first actuator and a diverting logic for diverting a portion of the input to a second actuator when the input is greater.Type: GrantFiled: February 8, 2005Date of Patent: June 24, 2008Assignee: Halliburton Energy Services, Inc.Inventor: Jason D. Dykstra
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Patent number: 7321216Abstract: This invention provides a motor control apparatus and vehicle steering apparatus capable of determining whether the motor control CPU is normal or abnormal with an inexpensive structure.Type: GrantFiled: November 17, 2004Date of Patent: January 22, 2008Assignee: JTEKT CorporationInventor: Hiroshi Suzuki
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Patent number: 7298105Abstract: Motor drives, motor speed controllers, motor speed estimation systems, and methods are presented for controlling motor speed and for estimating motor speed, in which a speed estimate controller provides a rotor speed estimate based on a first error term from a torque-based MRAS component for a first range of motor speeds and based on a second error term from a rotor flux-based MRAS component for a second range of speeds.Type: GrantFiled: December 21, 2006Date of Patent: November 20, 2007Assignee: Rockwell Automation Technologies, Inc.Inventors: Haihui Lu, Wei Qian
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Patent number: 7193387Abstract: Motor drives, motor speed controllers, motor speed estimation systems, and methods are presented for controlling motor startup speed and for estimating motor speed during startup, in which a speed estimate controller provides a rotor speed estimate based on a first error term from a torque-based MRAS component for a first range of motor speeds and based on a second error term from a rotor flux-based MRAS component for a second range of speeds.Type: GrantFiled: March 14, 2006Date of Patent: March 20, 2007Assignee: Rockwell Automation Technologies, Inc.Inventors: Haihui Lu, Wei Qian
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Patent number: 6646397Abstract: An integrated control and diagnostics system for a controlled system (e.g., a motor) includes a diagnostics module and a controller coupled to the motor. To optimize operation, the diagnostics information signal is used to modify the control provided by the controller as required. Moreover, the output of the control module is coupled to the diagnostics module so that the health assessment made by the diagnostics module can be based at least in part on the output of the controller. The invention uses a model-based diagnostics approach that allows integration of control algorithms with diagnostics algorithms to intelligently trade off optimizing performance to avert or accommodate failures, and to meet performance requirements in a wide range of applications.Type: GrantFiled: July 23, 2001Date of Patent: November 11, 2003Assignee: Rockwell Automation Technologies, Inc.Inventor: Frederick M. Discenzo
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Patent number: 6445879Abstract: A method for braking a washing machine in accordance with the present invention comprising the steps of: setting up an initial data of a duty ratio corresponding to a detected speed and a rotating position; discharging a voltage of the capacitor filter during a duty-on cycle according to the duty ratio set up in the preceding step; and charging a voltage to the capacitor filter during duty-off cycle when the duty-on cycle of the preceding step is finished. As described above, the dynamic braking resistor is not used in the method for braking the washing machine according to the present invention so that the size and the production cost are reduced.Type: GrantFiled: July 10, 2000Date of Patent: September 3, 2002Assignee: LG Electronics Inc.Inventors: Sang Chul Youn, Joo Hwan Lee, Chul Woong Lee, In Hwan Ra, Beom Seok Ko
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Patent number: 6441579Abstract: An available input of to a motor controller is used to measure the motor power supply voltage. Typically, a scaled down version of the voltage is sensed. The microprocessor is used to calculate the motor control current, in that case, is then calculated from the scaled down version. A scale factor that depends upon the sensitivity of the motor current to the motor supply voltage is calculated by the microprocessor. Driving parameters in the controller are then adjusted to account for the scale factor. In a preferred embodiment, the driving parameters are PWM parameters, and the microprocessor multiplies the measured power supply voltage to obtain a scale factor that can then be multiplied by the nominal PWM values to obtain the new PWM values.Type: GrantFiled: January 26, 2001Date of Patent: August 27, 2002Assignee: Hewlett-Packard CompanyInventors: Curt Van Lydegraf, Steve Gothard, Steve Kranz, Gary T. Brown
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Patent number: 6366048Abstract: A method and an apparatus for regulating the phase current in the windings of a reluctance machine. Regulation is carried out using a digital regulator, which operates using a PI characteristic and presets pulse-width-modulated pulses for a DC chopper controller. Set values, which are a function of the phase voltage, are superimposed on the regulator manipulated variable by means of a pilot control.Type: GrantFiled: December 22, 2000Date of Patent: April 2, 2002Assignee: DaimlerChrysler AGInventor: Andreas Greif
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Patent number: 6359416Abstract: A method and apparatus for controlling a synchronous frame current regulator wherein the apparatus includes a current predictor and a current predictor adjuster, the current predictor predicting the current provided to a plant from both a forcing function and an actual current value and the adjuster adjusting the current prediction based on a difference between the current prediction and the actual current sampled thereby driving the actual current so as to conform with a commanded current value.Type: GrantFiled: September 29, 2000Date of Patent: March 19, 2002Assignee: Rockwell Automation Technologies, Inc.Inventors: Aakash Vishalraj K. Rao, Russel J Kerkman, David W. Schlegel
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Patent number: 6326758Abstract: An integrated control and diagnostics system for a controlled system (e.g., a motor) includes a diagnostics module and a controller coupled to the motor. To optimize operation, the diagnostics information signal is used to modify the control provided by the controller as required. Moreover, the output of the control module is coupled to the diagnostics module so that the health assessment made by the diagnostics module can be based at least in part on the output of the controller. The invention uses a model-based diagnostics approach that allows integration of control algorithms with diagnostics algorithms to intelligently trade off optimizing performance to avert or accommodate failures, and to meet performance requirements in a wide range of applications.Type: GrantFiled: December 15, 1999Date of Patent: December 4, 2001Assignee: Reliance Electric Technologies, LLCInventor: Frederick M. Discenzo
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Patent number: 6252369Abstract: A motor speed controller with high speed response characteristics.Type: GrantFiled: April 24, 2000Date of Patent: June 26, 2001Assignee: Kabushiki Kaisha Yaskawa DenkiInventors: Yasuhiko Kaku, Takashi Kitazawa, Tadashi Okubo
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Patent number: 6046560Abstract: A motor controller controls the operation of an electric motor (28). The motor controller includes sensors (30, 97, 102) for sensing at least one dynamic operating characteristic of the motor and for providing a signal indicative of the at least one sensed dynamic motor operating characteristic. A variable gain regulator (190) receives a current command request signal having a value and provides a motor current control signal having a value functionally related to the value of the received current command request signal and a gain control value. A gain scheduler (196) is operatively coupled to the variable gain regulator (190) and to the sensor (30, 97, 102) for providing the gain control value to the variable gain regulator (196) in response to the sensed at least one dynamic motor operating characteristic to thereby control the amount of gain of the variable gain regulator (190).Type: GrantFiled: March 20, 1998Date of Patent: April 4, 2000Assignee: TRW Inc.Inventors: Engelbert Lu, Kevin M. McLaughlin
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Patent number: 5998957Abstract: The invention provides a controller for specifying a drive voltage for synchronous motors relative to a desired speed profile. The controller senses motor current and optionally senses motor rotational position. A motor torque reference is first determined to balance (a) an estimated motor load torque, (b) the reference speed profile, and (c) a filtered incremental friction. A reference torque is then determined for the operating speed, and a reference current is determined to produce the reference torque. A primary voltage module then determines a primary voltage as a function of the calculated motor torque and the reference motor current to create a reference current at the operating speed. An incremental voltage module determines an incremental voltage based on an incremental resistance and an incremental back EMF of the motor. The primary and incremental voltages are then summed specify the applied voltage to drive the motor to the reference speed profile.Type: GrantFiled: April 28, 1998Date of Patent: December 7, 1999Assignee: SatCon Technology CorporationInventors: Gilead Tadmor, Aleksandar M. Stankovic
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Patent number: 5838132Abstract: A device for outputting a suitable rotation torque relative to a load torque or actual torque exerted on a stepper-motor when the stepper-motor is used as a drive of an image processing device. The output torque of the stepper-motor depends on a supply current to the stepper-motor. CPU determines a suitable supply current using a table in ROM so that the stepper-motor is able to rotate at an optimum rotation torque. To this end, CPU sends a particular signal to the motor driver so that an appropriate supply current is supplied to the excitation phases A/B of the stepper-motor. The CPU determines the load torque based on an integrated current fed to the stepper-motor during a particular period. The CPU calculates difference between the load torque and rotation torque and determines the signal to be applied to the motor driver based on the torque difference.Type: GrantFiled: October 20, 1997Date of Patent: November 17, 1998Assignee: Murata Kikai Kabushiki KaishaInventor: Makoto Tanaka
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Patent number: 5737483Abstract: A motor speed control apparatus is provided in which the controllable frequency band of the control system can be sufficiently enhanced with a comparatively simple structure even if the frequency generator equipped into the motor is low in output frequency and the rotational accuracy can be highly improved even if the disturbance of high frequency components of load torque is applied to the motor. The frequency band of the control system can be improved by using the estimated speed signal as the speed feedback signal. A motor speed control apparatus superior in disturbance control characteristic can be realized through the feed forward compensation of an estimated load torque.Type: GrantFiled: October 25, 1995Date of Patent: April 7, 1998Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toshio Inaji, Eiji Ueda, Keisuke Matsuo
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Patent number: 5682459Abstract: A speed control for controlling the speed of a DC motor provides improved speed regulation during transient loading conditions. The control includes a regulating circuit having an output for controlling the armature voltage to the motor, An input speed reference signal corresponding to the desired speed is provided to the regulating circuit. A feedback signal proportional to armature voltage is also provided to the regulating circuit to establish an error signal for operating the control to regulate the voltage to the motor and therefore the motor speed, An IR compensating circuit provides increased motor voltage when the load increases. The voltage drop due to the armature circuit inductance is measured directly and also utilized to alter the output of the regulator to compensate for the inductive voltage drop occurring under transient loading conditions in a manner tending to establish the speed at the desired speed corresponding to the speed reference signal, during such conditions.Type: GrantFiled: July 27, 1995Date of Patent: October 28, 1997Inventor: Alan W. Wilkerson
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Patent number: 5625264Abstract: A system for controlling a brushless DC motor which can minimize a torque ripple of a motor, thus reducing minute vibrations of the motor and loading devices and increasing efficiency. The system includes a current command generator for producing a current command signal by multiplying a wave form of the current command signal in correspondence to position information by the desired size of the current command signal; a current controller for controlling actual current in the motor to follow the current command signal produced from the current command generator, in response to a feedback error control signal having proportion, integral, and differential elements, and producing a signal for turning ON/OFF following the current command; and an inverter circuit for controlling switching elements to be turned ON/OFF by the signal produced from the current controller, and the desired amount of current to be applied to three-phase coils by a power supply unit.Type: GrantFiled: January 24, 1995Date of Patent: April 29, 1997Assignee: Samsung Aerospace Industries, Ltd.Inventor: Sung-jung Yoon
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Patent number: 5577153Abstract: A control circuit for a series type dc motor. The control circuit uses a switching cell to control motor speed. The switching cell and motor receive power from a filtered dc supply. A tachometer generator produces a voltage proportional to motor speed. The speed voltage is compared to a speed reference signal voltage and the difference is proportionally integrated to develop a speed error signal voltage. The speed reference signal voltage is developed at a summing node where a current generated by the control's microcontroller is summed with a current proportional to the input ripple voltage of the control's dc supply. The microcontroller also receives a voltage proportional to the control's dc input as a reference. The speed error signal voltage is compared with the output voltage of a current sensor that is in series with the motor feeder arrangement and the comparator's output is used to reset a bistable flip flop.Type: GrantFiled: January 24, 1995Date of Patent: November 19, 1996Assignee: Whirlpool Europe B.V.Inventor: Cesare A. Bocchiola
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Patent number: 5563980Abstract: Provided is a brushless DC motor speed controller in which the speed feedback signal needed for speed control is obtained from the commutation signals generated by the magnetic-pole sensor in the brushless DC motor. The-brushless DC motor speed controller includes an edge detector, which generates a pulse each time a rising or falling edge is detected in the signal from the magnetic-pole sensor of the brushless DC motor. A frequency multiplier is used to multiply the frequency of the pulse train from said edge detector. A frequency-to-voltage converter is used to convert the output pulse train from said frequency multiplier into a positive analog voltage, with the level of the positive analog voltage being in proportion to the speed of the brushless DC motor. A motor rotating direction detecting circuit receives the output signal from said magnetic-pole sensor and thereby detects in which direction the brushless DC motor currently rotates.Type: GrantFiled: December 14, 1994Date of Patent: October 8, 1996Assignee: Industrial Technology Research InstituteInventors: Tshaw-Chuang Chen, Hong-Shi Chang, Huan-Jen Yang
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Patent number: 5533166Abstract: A method for calculating a speed estimated value in a speed control system, comprises the steps of: (a) storing the number of speed detection pulses obtained at each interval of a speed control process and time that the speed detection pulse was obtained; (b) calculating a detection speed from the number of latest speed detection pulses and its detection time, and the number of the previously stored speed detection pulses and its detection time; (c) executing an averaging process of motor model output corresponding to time that the detection speed was obtained; (d) obtaining a difference between an output obtained at said step (c) and the detection speed; (e) executing a calculation of a load torque estimation by multiplying the difference of the step (d) by an observer gain; (f) executing an estimation of a motor speed for next processing from the difference of the step (d) and a difference between the detection speed and the motor model output; (g) calculating an output of a speed amplifier by constitutingType: GrantFiled: March 2, 1995Date of Patent: July 2, 1996Assignee: Kabushiki Kaisha MeidenshaInventors: Yasuhiro Yoshida, Yasuhiro Yamamoto
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Patent number: 5481641Abstract: A control apparatus for controlling a motor includes: a command unit for generating a command signal including a running command signal and a stopping command signal; a rotation sensor for generating an AC signal having a period corresponding to a rotational speed of the motor; a speed detector for detecting a rotational speed of the motor from the AC signal generated by the rotation sensor; a compensator for generating a control signal for controlling the motor, and a driver for driving the motor in response to the control signal generated by the compensator.Type: GrantFiled: July 7, 1993Date of Patent: January 2, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Akihiko Nakamura, Yoshio Sakakibara, Makoto Gotou, Kazuhiko Kobayashi
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Patent number: 5384526Abstract: A control system having proportional and integral functions for controlling the rotational speed of a motor. The system includes a self-limiting integrator for avoiding or limiting integral wrapup, a problem commonly associated with integral control. The self-limiting integrator includes an integrator, limit comparator, OR gate, delay circuit, and sign reversal circuitry. The integrator reverses direction of integration when an error limit is realized. The error limit, a preestablished and adjustable value, can be used to determine the rise and settle time of the speed of the motor independently of the gain.Type: GrantFiled: July 13, 1993Date of Patent: January 24, 1995Assignee: WangDAT, Inc.Inventor: George J. Bennett
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Patent number: 5375186Abstract: An apparatus for stabilizing the speed of a motor has a phase comparator that identifies a phase difference between a reference signal and a speed signal. The apparatus acquires the speed of the motor and generates an output signal proportional to the identified phase difference. A controller receives the output signal. A control circuit for the motor is connected to the controller. The phase comparator comprises a sample-and-hold element, a sampling pulse shaper that is connected thereto and is input with the speed signal, a pulse shaper input with the reference signal, and a signal generator connected to the output of the pulse shaper and to the input of the sample-and-hold element.Type: GrantFiled: June 24, 1993Date of Patent: December 20, 1994Assignee: Linotype-Hell AGInventor: Gerd Schuettpelz
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Patent number: 5325460Abstract: A system and method for controlling the speed of a motor operating in an extremely low speed range and having a rotary pulse encoder which outputs a pulse whenever a rotation axle of the motor has rotated through a predetermined angle. The extremely low speed range is defined such that its pulse interval of the output pulses is longer than a speed control period of the system are disclosed, load torque estimated value observer is provided. The least order disturbance observer includes a first calculating block which calculates an estimated value of the motor speed n.sub.M ' (j) of a motor model on the basis of a torque command and a load torque estimated value: a second calculating block which calculates an average value of the motor speed at each pulse interval n.sub.M ' (j).Type: GrantFiled: May 20, 1992Date of Patent: June 28, 1994Assignee: Kabushiki Kaisha MeidenshaInventors: Tetsuo Yamada, Tatsuoki Matsumoto, Masayuki Mori
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Patent number: 5278486Abstract: The present invention relates to an induction motor, and a method of adjusting slip angular velocity of an induction motor, based on the voltage, current and velocity of the induction motor and compensating the slip angular velocity using vector control of the induction motor by way of a current controllable inverter.Type: GrantFiled: August 14, 1992Date of Patent: January 11, 1994Assignee: Samsung Electronics Co., Ltd.Inventor: Dong-Il Kim
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Patent number: 5278485Abstract: A control circuit for an induction motor calculates the d-axis current and q-axis current of a rotor in the motor and estimates the variation of the flux and resistance of the rotor on the basis of the d-q axis currents. As a result, a three-phase current for compensating for the resistance of the rotor varied due to the temperature and environment is suitably controlled to obtain high-performance of the motor.Type: GrantFiled: September 11, 1992Date of Patent: January 11, 1994Assignee: Samsung Electronics Co., Ltd.Inventor: Dong-Il Kim
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Patent number: 5167002Abstract: An apparatus and method for reducing synchronous speed variations in an electric motor having a rotating shaft, comprises a speed transducer for generating a continuous analog speed signal corresponding to the speed of the motor shaft including its synchronous and asynchronous speed variations. A trigger signal is generated each time the shaft rotates through a reference position and is used in conjunction with the speed signal in a fast Fourier transform analyzer to resolve the analog signal into a synchronous time averaged signal which varies with the synchronous speed variations but which eliminates the asynchronous speed variations. An arbitrary function generator is connected to the analyzer for generating an antiwave pattern having a frequency phase and amplitude relative to the waveform from the analyzer. The function generator is connected to a motor controller and superimposes the antiwave pattern onto a control signal internal to the controller which is thereafter applied to the motor.Type: GrantFiled: August 14, 1991Date of Patent: November 24, 1992Inventor: Robert M. Fridhandler
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Patent number: 5023924Abstract: In order to provide a speed control apparatus for a movable equipment having small torque ripples and speed variation, the present invention has a speed control means which comprises a driver for providing a current or a voltage having a magnitude corresponding to the instructed speed, a speed detection circuit for detecting a speed on the basis of a signal from the speed detector and a microcomputer for driving the driver by comparing the speed instruction signal with a speed signal obtained from the speed detection circuit. The microcomputer includes a harmonic wave component detecting means for detecting a harmonic wave component contained in a speed variation mode which is obtained from the speed detection circuit and has a function of making the gain of a speed control system variable by the harmonic wave component detected by the harmonic wave component detecting means.Type: GrantFiled: February 2, 1990Date of Patent: June 11, 1991Assignee: Hitachi, Ltd.Inventors: Fumio Tajima, Hiroshi Katayama, Kunio Miyashita, Shigeki Morinaga, Seiichi Narushima
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Patent number: 4831317Abstract: In a method of controlling a servomotor, a high output can be fetched from the servomotor by a motor-current control unit of a simple construction, while protecting switching elements of the control unit against excess current. The deviation between a command current (Ir) for of a plurality of winding portions constituting an armature winding of each phase and a current (Ia, Ib) flowing through each winding portion is integrated by an integrating element (9, 9'). The current (Ia, Ib) is amplified by means of a proportional element (10, 10'), and the individual currents (Ia, Ib) are controlled for substantially independent and equal values by means of one PWM control section (3) operating in response to a control signal which is obtained by adding outputs from both the elements (9.about.10').Type: GrantFiled: October 5, 1987Date of Patent: May 16, 1989Assignee: Fanuc LtdInventors: Keiji Sakamoto, Toshio Kobayashi
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Patent number: RE33500Abstract: A digital proportional-integral controller for controlling the speed of a d.c. electric motor in a copying machine and synchronizing it with the speed of another motor in the copying machine. The proportional stage and the integral stage of the controller are each formed by an up/down counter which counts up or down depending upon the pulses of the actual speed signal and the reference signal. Logic circuits are provided for processing the speed signal pulses and the reference signal pulses before they are fed to the up/down counters. The controller also has an interface for a two-wire bus system over which data and commands for adjusting and varying the control parameters can be input.Type: GrantFiled: July 1, 1988Date of Patent: December 18, 1990Assignee: Oce-Nederland B.V.Inventor: Wilhelmus T. L. Bisseling