Abstract: A method for controlling a system for a motor vehicle is disclosed. The system includes an actuator, a volatile memory (RAM) in which an item of position information of the actuator (IPRAM) is stored, and a long-term memory (EPROM). The following are stored in the long-term memory (EPROM): at least one item of position information (IPROM) of the actuator and an item of information relating to the powering down of the actuator (IHT), which assumes a first value (v1) when the system has been powered down in a controlled manner and assuming assumes a second value (v2) when the system has suffered a fault causing the current value of the position of the actuator stored in the volatile memory (RAM) to be deleted.

Abstract: To achieve peak acoustic and power performance, the coil or applied current should be in phase or substantially aligned with the back electromotive force (back-EMF) voltage. However, there are generally phase differences between the applied current and back-EMF voltage that are induced by the impedance of the brushless DC motor (which can vary based on conditions, such as temperature and motor speed). Traditionally, compensation for these phase differences was provided manually and on an as-needed basis. Here, however, a system and method are provided that automatically perform a commutation advance by incrementally adjusting a drive signal over successive commutation cycles when the applied current and back-EMF voltage are misaligned.

Abstract: A method and apparatus are disclosed for determining a negative pressure generated by a suction pump of a topical negative pressure (TNP) system. The method includes the steps of disconnecting a drive voltage from a pump of the TNP system, determining an EMF generated by a free-wheeling element of the pump, selecting a new drive voltage for the pump and reconnecting the new drive voltage to the pump.

Abstract: A technology for correctly detecting a rotating position of a rotator at the time of rotation start. A rotation control apparatus controls rotation of a motor, which includes a stator provided with a plurality of coils and a rotor having magnetism. At the time of detecting a position of the motor when the motor is stopped, a control part supplies a current to a plurality of different paths including the coils, a stopped position detecting part measures the current flowing in each of the plurality of paths, judges the order of the measured current values, and a rotating position of the motor is detected based on the order. Based on a combination of a path showing the highest current value and a path showing the second highest current value, the stopped time position detecting part judges a position of the motor.

Abstract: A position determination circuit uses the commutation sensor of a brushless DC motor to determine the position of an actuator and/or actuated component 125. The commutation sensor supplies a rotational position signal representative of the rotational position of the motor to a pulse generator. The pulse generator generates a pulse each time the rotational position signal represents a complete revolution of the brushless DC motor. The generated pulses are supplied to an integrator circuit, which selectively supplies a position signal having a voltage magnitude representative of the position of the actuator and/or component.

Abstract: Apparatus for reconstructing the phase currents of a multiphase load driven by a multiphase inverter fed by a DC link and controlled by a PWM controller, the apparatus including a sensor in the DC link, first and second sampling arrangements for sampling the current in the DC link by obtaining an output from said sensor, the first sampling arrangement obtaining a first sample of the current in the DC link during a first time period corresponding to a first switching pattern of said multiphase inverter and storing said first sample; the second sampling arrangement obtaining a second sample of the current in the DC link during a second time period after said first time period and corresponding to a second switching pattern of said multiphase inverter and storing said second sample; an A/D converter for converting said first sample to a digital signal during a time period after said first time period and for converting said second sample to a digital signal during a following third time period.

Abstract: A laser level with a sensorless DC motor controller having a feedback sampling circuit connected in parallel with the coil to sense back EMF. An integrator provides a feedback signal from the sensed back EMF, which the amplified difference from a reference level is used as a pulse width control signal. A pulse width modulation generator uses the control signal to generate variable “on” time pulse widths for each motor drive pulse such that high resolution is provided to the DC motor, permitting accurate rotor position at low rotational speeds. It is emphasized that this abstract is provided to comply with the rules requiring an abstract to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims.

Abstract: An electronic circuit and software control methodology tracks motor position in a motor drive system. High power consumption position transducers, such as inductive sensors or optical encoders, can be controlled in a variable active duty cycle mode to reduce power and yet maintain motor position information while the main power is off. A lower power battery backup circuit is implemented as a secondary power source, and is automatically brought in operation when the main power supply is disabled. A dedicated control circuit operates during AC power outages, and the circuit average power can be controlled to a minimal rate, based on the rate of change of motor position. The motor can be externally driven, up to a defined limit speed, without losing its actual position information.

Abstract: A system and method is disclosed for feedback velocity control of a D.C. motor. The system includes a motor (30) which is represented by its circuit equivalent--a series combination of an inductance (32), a resistor (34) and a back EMF source (36). The drive to the motor (30), supplied by a controller, is periodically inhibited by timing logic (22) and AND gate (20). Once the inductive transient decays via clamping diode (38) such that the motor current is zero, switch (40) is closed and the internally generated motor voltage is sampled by a capacitor (42). A/D converter (44) transforms the sampled value to a digital value and sends it to the controller. The controller compares it to a predetermined desired value then makes the necessary adjustments to the drive signal.

Abstract: Methods and apparatuses are provided to identify and extract a torque ripple signal found in the back-emf signal from an electric motor. The torque ripple signal is used in a feedback control loop to reduce the amount and effects of torque ripple in the motor and the motor system. A motor controller is provided to reduce torque ripple in an electric motor. The motor controller is suitable for controlling the speed or torque or other related parameters associated with the electric motor. A disc drive apparatus for use in information storage and retrieval systems is provided. The disc drive apparatus includes an electric motor, an information storage disc, and a motor controller. A method is provided for reducing the effects of torque ripple in an electric motor by sampling the back-emf signal generated by the electric motor, extracting the torque ripple signal from the back-emf signal, and generating an AC component signal proportional to the torque ripple signal.

Abstract: A device for the optimizing of the speed control of an electric subfractional horsepower motor for dental instruments is provided wherein it is possible to operate the motor in any desired speed range. The device contains a first module for regulating the speed by voltage measurement, a second module for regulating the speed by current-load compensation, and means for deciding which of the two modules and in what proportion they assume speed regulation of the motor.

Abstract: A digital process generates a pulse-width modulated (PWM) signal for providing current to a load. In one embodiment, an input signal is repeatedly sampled at times corresponding to edges of a reference square wave. The sampled values are used to produce a PWM signal, each pulse of the PWM signal having a width corresponding to one of the sampled values. In another embodiment, the sampled values are used to produce a series of intermediate pulses, the intermediate pulses being used to construct an output PWM signal. The pulses of the output PWM signal generally have leading and trailing edges which do not coincide with the times at which sampling occurs. Therefore, in the second embodiment, sampling does not occur when the PWM signal is opening or closing a switch, and the sampling tends to occur near the average value of the input signal.

Abstract: 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.

Abstract: An electric shaver comprises: a current detecting circuit which detects load current of a motor; a microcomputer which samples the values detected by the current detecting circuit periodically to judge the size thereof, and the positive or negative results of the difference with the values sampled at last, to output a predetermined signal respectively responsive to the results; and a control circuit which controls the rotational speed of the motor according to the output signal from the microcomputer, whereby in the case where load current of the motor detected by the current detecting circuit is large, the microcomputer reckons that beards are thick, conversely, in the case where the load current is small, the microcomputer reckons that the beards are thin, thereby driving the motor at an optimum speed respectively.

Abstract: An error signal detection circuit in a servo control device comprises a reference signal generation circuit for selectively generating reference signals of different periods, each having a slope which changes from a reference value at a substantially constant gradient, an error detection timing generation circuit for generating timing of detection of an error signal of an object of control, an error signal detection circuit for generating an error signal by detecting the value of a reference signal generated by the reference signal generation circuit at a timing provided by the error detection timing generation circuit, and a slope varying circuit for varying the slope of the reference signal in accordance with the period of the reference signal.

Abstract: The motor speed control circuit senses average back EMF as a measure of motor speed. The back EMF charges a capacitor circuit which accumulates charge and develops a voltage indicative of the motor speed. A sample and hold circuit may be used to sample the back EMF when the motor is switched off during each cycle. This voltage is compared with a reference voltage indicative of the desired motor speed. An error signal is generated by comparing the desired speed with the actual speed and this error signal is used to generate a variable duty cycle pulse train which gates the power controlling transistor on and off to control motor speed. A logic gated or SCR gated voltage boosting circuit operates in synchronism with the gating pulse train to drive the power transistor hard into saturation. This lowers the resistance of the power transistor, causing less energy dissipation as waste heat.

Abstract: A circuit for controlling the speed of a subfractional horsepower DC motor has a driver stage with a switch that interrupts the motor current in repeated succession so that a pulse-like current is provided, and the motor EMF is sampled synchronously with the motor current interruption, with the sampled value being supplied to a comparator wherein it is compared to a rated value. The output of the comparator is used to control the driver stage which includes the switch. Two pulse duration modulators are provided which respectively independently control the motor current and voltage. The pulse duration modulator which controls the current generates pulse pauses which are always sufficiently long to permit the EMF measurement to be completed. The pulse duration modulator operates at a frequency above the audible frequency range so that its pulse pauses are short enough to prevent the motor current from noticeably failing or being completely interrupted.

Abstract: A circuit for controlling the speed of a DC motor provides delay and sampling means in the feedback loop to delay the triggering of the SCRs driving the DC motor and measured the motor armature voltage during the period of the delay, thereby eliminating errors in the armature motor voltage caused by the SCR motor excitation.Alternatively, the current to the motor is measured to generate a pulse output for initiating an interval during which the measured armature voltage is sampled and transmitted to a summator for generating an error signal controlling application of power to the DC motor whereupon the aforesaid interval is terminated upon receiving a pulse indicative of power application to the DC motor.

Abstract: A motor control system and related method are provided for phase and frequency locked operation of multiple spindle motors in a computer disk drive environment or the like, for coupling two or more disk drive units together to provide expanded data storage capability. The control system comprises a hybrid digital and analog network for producing a pulse width modulated control signal to control a disk drive spindle motor in a manner achieving frequency and phase locked relation with a reference signal. Multiple spindle motors are similarly driven in relation with the same reference signal, whereby the spindle motors are frequency and phase locked with respect to each other to permit, for example, parallel data transfer among the multiple disk drive units.