Abstract: The invention relates to a sensorless commutation of a direct-current motor. To allow an exact, easy to design, flexible, and highly integratable circuit arrangement for commuting motor devices, analogue phase detectors are replaced by digital devices, in particular Sigma-Delta-modulators, which oversample the induced voltages of coils of said motor.

Abstract: A method for determining the position of an element driven by the drive shaft of a commutated direct current (DC) motor includes counting current ripples detected in an armature current signal as the motor rotatably drives the shaft. A frequency spectral analysis of the armature current signal is performed to determine frequency components of the armature current signal. The frequency components are analyzed to determine which of the frequency components is indicative of the current ripple frequency. The current ripple frequency is monitored for changes over time while the motor drives the shaft. The number of counted ripples is modified upon a change in the current ripple frequency in a time interval if the current ripple frequency change deviates from the current ripple frequency more than a threshold deviation for the time interval. The rotational position of the shaft is determined based on the modified number of counted ripples.

Abstract: An apparatus for controlling a rotational speed of a motor, coupled to a sensing unit capable of outputting a sensing signal. The apparatus includes a controlling unit, coupled to the sensing unit, for outputting a controlling signal according to the sensing signal and independently of the rotational speed of the motor. The controlling signal is a square wave and has a duty ratio that is determined by the sensing signal. The apparatus also includes a driving unit, coupled to the controlling unit, for outputting a driving signal to a motor rotor according to the duty ratio of the controlling signal. The driving signal also is a square wave. The rotational speed of the motor rotor is determined by the duty ratio of the driving signal.

Abstract: A motor speed resolution enhancement method and system. A display system controller (202) measures the frame rate of an incoming signal to determine the desired color wheel speed. A digital speed control word (212) representing the desired color wheel speed is written to the motor control circuit (204). The motor control circuit uses the digital speed control word (212) to generate analog control voltages (214) that drive the motor (206). The motor controller (204) also detects the position of the motor and generates a series of commutation interrupts (216). The display system controller 202 accurately measures the input signal's frame rate to determine the proper rate at which to spin the color wheel. The resulting desired speed word has a higher resolution than the motor control circuit (204) is able to receive. The disclosed invention provides a method of increasing the resolution of the digital speed control word (212) without upgrading the resolution of the motor control circuit (204).

Abstract: Disclosed are circuits and circuit architectures for partitioning between a hard disk drive assembly mixed signal spindle motor driver and additional associated digital circuitry.

Abstract: A motor controller system (15a) for dc power source motors (10) which includes a sensor device (16) that operates to measure and generate a voltage signal from the motor current and the rate of change of said current, and a programmable input/output processor (12) which receives voltage signals as input from the motor current, dc power source (11) and/or motor (10) and compares on or more of these voltage signals to one or more control parameters. Based upon these comparisons, the processor (12) generates a pulse width modulation control signal, which triggers a switching mechanism (14) and related interrupt service routing to make adjustments to the operational parameters of the motor by periodic interruption of the motor current.

Abstract: The invention concerns a method for digital control of a universal motor, in particular for electrical household appliance, comprising steps which consist on: measuring said engine (21) rotation speed; determining the difference between the measured speed and a set speed; and controlling the motor on the basis of said difference. Said method further comprises a step (24, 25) which consists in estimating at least one of the values of the resisting torque (C) and the current (i) in the motor windings. The invention is useful for controlling washing machines.

Abstract: A motor control circuit for use in a motor circuit includes a varying duty cycle pulse width modulation circuit and a switch. The varying duty cycle pulse width modulation circuit is operable to generate a PWM signal having a varying duty cycle, wherein an average of said varying duty cycle corresponds to a desired motor speed. The switch has a control input operably coupled to the pulse width modulation circuit to receive the PWM signal therefrom. The switch further includes first and second terminals, the first terminal adapted to be coupled to a coil of the motor circuit, the switch operable to selectively electrically connect and disconnect the first and second terminals based in part on the PWM signal received by the control input.

Abstract: A speed control device particularly adapted for use with electrical motor-driven hand tools has digital operator input controls. A semiconductor switching device controls a percentage of ON time for the electric motor in the hand tool. Discrete and repeatable settings are selectable to a user through digital input switches.

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

Abstract: A fan motor whose speed is controlled by an operating period of pulse waves includes first and second rectifying circuits, a voltage comparison circuit, and a differential amplifier. A pulse wave is inputted into the first rectifying circuit, an actual speed signal detected from the fan is inputted into the second rectifying circuit, and the pulse wave and the speed signal are compared in the voltage comparison circuit. After comparison, a comparison voltage is outputted to a negative terminal of the differential amplifier. A partial voltage from a source voltage is connected to a positive terminal of the differential amplifier. The differential amplifier outputs a drive voltage after calculating a voltage difference between the comparison voltage and the partial voltage. Speed of the fan is changed in response to a change in the value of the drive voltage.

Abstract: A fan speed control system for controlling the operation and speed of a fan is described. The fan speed control system includes a power control block for supplying an output voltage to the fan. An integrated circuit fan controller causes a resistor divider circuit to operably divide a selected portion of the output voltage. The integrated circuit fan controller comprises a data register which receives values indicative of control or speed operands from a host. A logic state machine translates these values into appropriate logic signals and provides the signals to the resistor divider circuit. A timing reference or an oscillator controls the proper sequencing and timing relationship of the logic state machine. To turn the fan on, the following sequence of steps occurs. The power control block is turned off causing the output voltage not to be supplied to the fan. The logic state machine controls the resistor divider circuit to divide the output voltage to be supplied to the fan.

Abstract: A three-phase motor having three Hall-effect devices for production of as many rotor position signals for use in excitation control of its windings, the signals being indicative of the angular position of the motor rotor with respect to the stator and having phase differences of 120 degrees. A motor speed control system is disclosed which utilizes the rotor position signals for detection of the actual running speed of the motor. Included are differentiating circuits connected one to each Hall-effect device for producing outputs in prescribed phase relationship with the rotor position signals. Connected to the differentiating circuits, switching transistors are controlled by binary switch control signals derived from the rotor position signals, passing the positive half-waves, or approximately positive half-waves, of the differentiating circuit outputs. The thus-obtained half-waves are then added together into a motor speed signal representative of the actual running speed of the motor.

Abstract: A two-terminal motor can be connected to a two-line voltage supply network utilizing a controller in which a control element is in series with the current-measuring component and both are connected to a microcontroller.

Abstract: A BEMF detector and method detect the BEMF of a three-phase motor using a fully differential detection system. The motor has a first coil coupled between a first coil tap and a center tap, a second coil coupled between a second coil tap and the center tap, and a third coil coupled between a third coil tap and the center tap. The BEMF detector includes a differential amplifier having first and second inputs and first and second outputs, with the first input being coupled to one of the coil taps and the second input being coupled to the center tap. The BEMF detector also includes a comparator having first and second inputs coupled respectively to the first and second outputs of the differential amplifier and an output at which a BEMF signal is produced that is related to the BEMF of the motor. The differential amplifier may be part of an anti-alias filter structured to fix to a known stable value a common mode at the outputs of the differential amplifier.

Abstract: A process and a system for controlling an electrohydraulic pressure supply for an auxiliary power device of an automotive vehicle in which a hydraulic pump system is operated by means of an electric motor the speed of rotation of which is controlled by operating parameters. In order to operate the auxiliary power system with the least possible energy, the changes in speed of rotation which differ from a predetermined desired speed of rotation of the electric motor are recognized and levelled out. In order to operate the power-assisted system with the least possible energy, the switching of the electric motor (2) from stand-by operation to full-load operation, or vice versa, takes place as a function of the speed of rotation (n) of the electric motor (2).

Abstract: A motor control circuit for a power tool includes a function switch which has a first battery contact, a speed control contact, a bypass contact and, a second battery contact connected in that order in a line. The function switch also has a movable contact which sequentially connects the first battery contact to the bypass contact, the speed control contact to the second battery contact, and the bypass contact to the second battery contact. A solid state switch has conduction path connecting the speed control contact to the second motor terminal wherein the conduction path is controlled in response to an oscillator signal.

Abstract: A motor control circuit, including a filter amplifier which includes a clamping circuit to limit the maximum voltage of the filter amplifier. The filter amplifier is clamped to essentially the same level as the following error amplifier, which drives the power transistor which drives the motor. Thus, the requisite control voltage is normally present anyway (since this voltage is used to limit the amount of maximum current in the motor). Since the corresponding level of current is selected to ensure adequate current during start up, this signal is therefore appropriate to limit the output voltage of the filter amplifier. This improvement adds very little circuit complexity, and reduces the settling time of the motor controller at startup.

Abstract: In a feedback control system with multivariable inputs and outputs, a network of plant actuators, each controlled by self-adaptive feedback control loops with pole-tracking zeroes, is provided as a plant or output load for a network of generally-conventional controllers. Each of the controllers sees a constant load, so the controller network can be viewed as having a constant gain-bandwidth characteristic transmission. The network of plant actuators cancels the effects the load inertias and its variations.

Abstract: A commutation control circuit provides a substantially periodic series of commutation signals to a conventional motor sequencer. The control circuit includes a frequency-to-current converter that receives the series of commutation signals and outputs a current that has a magnitude proportional to the average period of the series of commutation signals. The proportional current is then used to charge and/or discharge a known capacitance after a back-EMF sensor determines the appropriate starting time of a delay period. The capacitance and the proportional current are selected such that the proportional current charges the capacitance to a selected voltage level to trigger a commutation signal after the appropriate delay period.

Abstract: A cartridge of a single reel is inserted and information is recorded and reproduced by a helical scan type using a rotary head. A control pulse is reproduced from a recording signal of a control track of a magnetic tape by a fixed head. A repositioning operation and a high speed search are controlled on the basis of the control pulse. A torque ripple of a capstan motor is previously measured. When the tape runs, a motor drive current is corrected so as to reduce a torque change of one rotation on the basis of the measurement result, thereby improving a wow and flutter. A switching timing of motor coils by Hall sensors is set to an early timing, thereby suppressing a torque fluctuation. A regenerative braking circuit is formed by an OFF timing of a PWM control and a tape back tension is formed by a decrease in torque by the regenerative braking circuit. A tape thread and a tape wrap at the time of the insertion of the cartridge are simultaneously executed.

Abstract: A quiet motor speed controller is disclosed which varies an amplitude of an AC voltage signal provided from an AC source to drive an AC motor. The controller includes a first impedance in series connection between the source and the motor. A second impedance is electrically connectable with the first impedance in accordance with settings of a switch such that the total impedance interposed between the source and the load is varied by switching. The first and second impedances are substantially defined by first and second capacitive values, preferably including resistive elements to limit current flow at charging and discharging.

Abstract: A method of obtaining a very robust adaptive PI control method irrespective of fluctuation of parameters of a control object, wherein (speed command r-actual speed y) is used as a state variable Suf. Estimated values J*, A*, Gr*, and C* of inertia, coefficient of dynamic friction, gravitational disturbance depending on a robot angle, and Coulomb's friction, respectively, are obtained and a torque command .tau. is obtained in accordance with the following equation so as to cancel an error between each of the estimated values and its actual value to zero..tau.=K2.multidot.Suf+(K1/s).multidot.Suf+J*.multidot.r'+A*.multidot.y+Gr*. multidot.sin .theta.+Cf*+.tau.1.The first and second terms of the right side of the above equation are identical with a torque command obtained by the PI control. Furthermore, r' represents an acceleration of command; .theta. represents a rotational angle of a robot arm; and .tau.1 represents a switching input corresponding to miscellaneous disturbance.

Abstract: A method and apparatus for tuning an external velocity loop servo drive of the type including a controller, a command device, an external velocity servo amplifier, an actuator and a position feedback device. The tuning technique include the use of three unidirectional motion events of descending duration. In the first motion event the controller applies a control signal of known amplitude to the actuator and monitors the actuator velocity based upon the position feedback signals. The controller determines the actuator steady state velocity during the motion event and uses this value to determine a scaling factor for the servo amplifier. In a second motion event, the controller drives the actuator in acceleration and deceleration in response to a control signal of known amplitude. Based upon the times at which the actuator reaches certain anticipated velocities, the controller determines system dynamic characteristics.

Abstract: A method of measuring a linear velocity of a rotating disk on a disk drive system wherein a rotation of a spindle motor is controlled in accordance with a predetermined linear velocity which is generated based on a signal reproduced from the disk to control the initial rotation of the spindle motor. The linear velocity of the disk is determined by measuring one revolution of the disk and from the radius of the disk. The disk drive system includes a servo control system to measure the one revolution of the disk and to generate a servo control signal at a time corresponding to a predetermined number of output pulses from the spindle motor measured during the one revolution time of the disk. The servo control signal is supplied to the spindle motor to control its initial rotation.

Abstract: A motor control arrangement including a control circuit for controlling the speed of an electric motor (EM), which control circuit comprises a measurement resistor (MR) and a switching transistor (ST) having a control electrode and a main current path coupled in series with the electric motor (EM) and the measurement resistor (MR), a pulse width control stage (PW) coupled to the control electrode of the switching transistor (ST), a motor current measurement stage (MI) for controlling the pulse width control stage (PW) in response to a motor current of the electric motor (EM), and a motor voltage measurement stage (MV) for controlling the pulse width control stage (PW) in response to a motor voltage (EM) of the electric motor (EM).

Abstract: Apparatus and method for controlling an air distribution system of the type which includes a motor drivingly associated with a blower and a duct system, and further including a target air flow rate signal which represents a target air flow for the air distribution system. The apparatus and method provide control of the motor speed to maintain a rate of air flow in the system at substantially the target air flow rate regardless of the status pressure therein. The apparatus provides a speed signal representative of the speed of the motor, and a control signal in response to the target air flow rate signal and the speed signal, and controls the motor speed in response to the control signal. The central signal is provided independent of the duct system. Motor speed is controlled by applying a voltage to the motor which varies in accordance with the control signal for maintaining the rate of air flow in the system at substantially the target air flow rate regardless of the static pressure therein.

Abstract: A motor speed control device, preferably for use in a camera, controls a motor to rotate at a constant speed in accordance with a pulsed signal output from a motor speed detector, such as a photointerrupter. To overcome the control problems that occur when the motor abnormally stops rotating, preventing generation of pulsed, the motor speed control device includes a timer that measures elapsed time from a most recent pulse. When the elapsed time exceeds a predetermined value, the motor speed control device accelerates the motor so that control of the motor at a constant speed can continue.

Abstract: A vehicle power controller for a vehicle including a motor that drives the vehicle, a plurality of sensors and a motor controller, wherein the plurality of sensors includes an accelerator sensor for sensing a position of an accelerator pedal and a brake sensor for sensing a position of a brake pedal, and wherein the motor controller controls torque output of the motor. The vehicle power controller includes three components. The first receives signals from the accelerator sensor and the brake sensor. The second converts the signals for the accelerator sensor and the brake sensor into a torque value, and the third outputs the torque value to the motor controller for controlling the torque output of the motor.

Abstract: An electric shaver is provided with a motor to drive a cutter, a motor current sensing circuit, and a computation circuit which processes an output from the current sensing circuit. The computation circuit computes beard thickness, and a set range of motor rotational speed regulation according to beard thickness to lower rotational speeds for thin beards and to higher rotational speeds for thick beards, and thereby rotates the motor at optimum speeds according to beard thickness.

Abstract: The interface circuit has a single input terminal for receiving an analog or digital control signal indicative of the required speed of rotation of the motor. The type of input signal is recognised by means of comparator circuits. The input signal is processed differently according to its nature in order, in any case, to output an analog signal acceptable by the regulation and control circuit which pilots the motor.

Abstract: A method for measuring the rotary speed of a direct-current motor having a rotor and at least a shunt-wound field winding, wherein the field current includes an ac-component caused by mass-inhomogeneities in the rotor, including the steps of: frequency analyzing with a frequency analyzer the ac-component to form a frequency spectrum; selecting with a computing device a part of the frequency spectrum related only to the rotary speed; and determining from the selected part of the frequency spectrum the rotary speed of the motor.

Abstract: An x-ray tube (10) of a CT scanner has a rotating anode and rotor combination which is propelled by AC currents applied to run and phase windings (42, 46) by a starter (22). A monitor (24) includes Hall effect current detectors (40, 44) which detect the actual current flowing through the run and phase windings. The detected analog current values, voltage values, and the like are multiplexed (132) and digitized in a preselected order by an analog to digital converter (60) and stored in that order in a FIFO memory (62). A microprocessor (64) performs a Fourier transform (94, 96) to convert the digital run and phase signals into frequency spectra. The run and phase frequency spectra are compared (100, 102, 104, 106) with frequency spectra indicative of rotor speed, bearing wear, anode vibration, failure of the anode to rotate, and other conditions, analyzed for symmetry or other characteristics, or the like (FIG. 5 ) to generate digital run and phase reference signals.

Abstract: A multi-function hand-held power tool includes an electric motor for driving a tool holder and control means for energizing the motor in accordance with a selected combination of operating conditions under which the tool is to be used. Located on the housing of the tool is a keyboard for inputting to the control means information to define the selected combinations of conditions. The keyboard has a first single key for selecting a tool function, for example drilling, from a defined range of tool functions, a second single key from selecting a required workpiece material for example wood, from a defined range of workpiece materials, and two further keys for selecting, from a defined range, another parameter, for example drill size, appropriate to the selected tool function. A visual display also located on the tool housing is energizable to show symbols indicative of the selected combination of operating conditions.

Abstract: Disclosed are a traverse apparatus and an image recording apparatus including a rotary member for traversing a material to be traversed, a storage unit for prestoring rotation control data based on diameter data corresponding to a rotation angle of the rotary member from a reference position in its circumferential direction, a detection unit for detecting the rotation angle of the rotary member, and a control unit for controlling an angular velocity of the rotary member on the basis of an output from the detection unit and a content of the storage unit so as to make a traverse velocity of the material to be traversed constant.

Abstract: It is foreseen to measure the rotational speed (V) of a motor (4) by measuring the electromotive force (e.m.f.) This e.m.f. is calculated as the difference between the terminal voltage (Va) and the voltage drop at a reference resistor (S), through which the armature current flows, then this value is used as a velocity feedback signal for motor regulation. Particularly, the terminal voltage (Va) is cyclically measured at two successive close instants (t1, t2), during which the armature resistance (Ri) and the motor e.m.f. can be considered constant; these terminal voltage values (V.sub.at1, V.sub.at2) are stored, then elaborated to perform the actual armature resistance (Ri) during that interval (t1-t2), then this value is multiplied for the instant current (I). The result is then substracted from the terminal voltage (Va) and only at that time the resulting e.m.f. is used as a velocity feedback signal for the velocity feedback circuit. The apparatus for carrying out this process is also disclosed.

Abstract: Method of measuring the rotary speed of an electromagnetically actuated rotating device having at least one winding carrying a current, which comprises analyzing the frequency of a voltage corresponding to an alternating component of the current, and a device for performing the method.

Abstract: A generalized method of synthesizing control systems of instanteous response and zero error in both transient and steady state with respect to input commands and of infinite disturbance rejection ratio with respect to external distrubances, carried out in the state-space vector-matrix form for generality obviousness and applicability, comprising terms in a form of local positive feedback state variable differentiators for cancelling the derivative terms in each of the n first order differential equations describing an n-th order system in the state-space representation and thus yielding a zero-order system with the instantaneous response to the input command column vector, and further comprising terms in form of local controller positive feedback control loops for cancellation of a system matrix and thus providing a load/disturbance-invariant system with associated infinite disturbance rejection ratio. All local positive feedback loops are closed within a negative feedback control loops to ensure stability.

Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising a positive current feedback of a prescribed functionalism and a negative voltage feedback to ensure stability of the system. The prescribed functionalism of the current loop uses arithmetic elements as well as voltage and current measurements to provide for a parameter-free synthesis of the converter whereby the converter operates in the measurement-based mode, the measured variables being the voltage and the current associated with the impedance of interest, without a need to supply values of both resistive and reactive components of the impedance of interest. The converter is used in synthesizing electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero-order dynamics and without specifying the resistive and the inductive values of the motor impedance.

Abstract: 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.

Abstract: A disc record/reproduce apparatus with a brushless dc motor having no separate dedicated position sensor, controls rotation of the dc synchronous motor by back-electromotive force signals developed in windings of the brushless dc motor using a/d converter included in one-chip microprocessor in the first mode, and controls by position and index signals recorded on the disc in the second mode. During start-up, a start-up oscillator is used. The control with a back-electromotive force signal is provided to enable the microprocessor to write a position signal on a disc and provided for inspecting the brushless dc motor independently. In the second mode, functions for executing the back-electromotive force control in the microprocessor is disabled during recording and reproducing of data to prevent overload on the microprocessor which is busy because of communication with an external computer and control of head position.