Abstract: A motor control system 10 includes an engine cooling module 14 including a DC motor 12. The system includes a switch 18 constructed and arranged to be controlled by a pulse width modulated (PWM) signal 26. The switch 18 is operatively associated with the DC motor to control current to the DC motor and thus control the speed of the DC motor. A controller 20 is operatively associated with the switch. The controller is constructed and arranged to select periods, of a limited-pool of frequencies each being less than 500 Hz, from a pseudo-random sequence of periods and to send the selected periods to the switch, thereby controlling noise and vibration of the module.

Abstract: A motor speed control system 10 includes a permanent magnet direct current electric motor 12. A first switch 14 is operatively associated with the motor. A resistive element 16 is provided in series with the motor and the first switch. A second, pulse width modulated controlled, switch 18 is operatively associated with the motor. A controller 20 is operatively associated with the first and second switches for controlling the first and second switches independently and in combination to control current to the motor to operate the motor at various speeds.

Abstract: An electronically switched motor includes a stator-rotor assembly fitted with three-phase driving windings, a series of switches for powering the windings, and a control circuit suitable for regulating a speed of the motor as a function of a reference speed and a measured speed. The control circuit includes switch control elements to cause each switch to switch on and off in compliance with a repeated sequence selected to power the driving windings as a function of the reference speed and the measured speed. The sequence includes a succession of on/off pulses with a duty ratio. The control circuit is suitable for generating a first switch control mode for controlling the switches so that the switches are in an ON state or receive a succession of ON pulses over a first activation period and a second switch control mode for controlling the switches so that the switches are in an ON state or receive a succession of ON pulses over a second activation period larger than the first activation period.

Abstract: A motor speed control system 10 includes a permanent magnet direct current electric motor 12. A first switch 14 is operatively associated with the motor. A resistive element 16 is provided in series with the motor and the first switch. A second, pulse width modulated controlled, switch 18 is operatively associated with the motor. A controller 20 is operatively associated with the first and second switches for controlling the first and second switches independently and in combination to control current to the motor to operate the motor at various speeds.

Abstract: The invention relates to an electronically commutated motor (1) comprising P phases and N pairs of poles, in which a circular multipole encoder (12) is associated with the rotating ring (6a) of an anti-friction bearing (6), said encoder (12) comprising a main multipole track (12a) and a multipole commutation track (12b) comprising 2*P*N singularities (12b1-12b6) equidistributed angularly and a control device comprising a fixed sensor (15) capable of delivering square digital signals A, B in quadrature and a digital signal C in the form of 2*P*N pulses per revolution of the encoder (12), a circuit for commutating (20) the currents in the phase windings of the motor (1) and a control circuit (21) for the commutation circuit (20).

Abstract: A motor driving system is disclosed. The circuit includes a power converter for supplying a brushless motor having a permanent magnetic rotor with pulse-width modulation controlled driving power, a magnetic-pole position detector for detecting a magnetic-pole position of the motor rotor, a speed detector for detecting a rotational speed of the motor according to an output signal of the magnetic-pole position detector, a speed controller for outputting a deviation of an output signal of the rotational speed detector from a speed instruction, an instruction signal generating circuit for generating a plurality of instruction signals in response to an output signal of the speed controller, a circuit for generating modulated waves by selecting one of the plurality of instruction signals according to the magnetic-pole position of the motor, and a driving ct for controlling the power converter by means of pulse width modulation according to the modulated waves.

Abstract: A motor controller for a three-phase spindle motor used in the hard disc drive provides pulse width modulated (PWM) signals used to drive the motor. The PWM signals have duty cycles which are a function of rotational position of the motor, a magnitude control signal, a stored set of main waveform coefficients, a stored set of modifier coefficients, and a modifier signal. By varying the modifier signal, the duty cycle of the PWM signals can be varied to adjust the shape of the motor current waveform to match the torque profile of the motor.

Abstract: A motor drive apparatus that includes a digital controller for generating pulse width modulation (PWM) signals with predetermined duty factors, duty capacitors for converting the PWM signals into drive voltages applied to the motors; low pass filters for generating DC drive signals by removing AC components, and a PWM decoder for generating a voltage across the duty capacitors by charging the duty capacitors in one predetermined state (either high or low) of the PWM signals, and by discharging the duty capacitors in the other state of the PWM signals. Using the present invention, a motor can be driven with a digital controller not equipped with a D/A converter; and a drive voltage applied to the motor can be controlled by a gain of the amplifier and a power supply voltage.

Abstract: A foreign material interference detection apparatus for an opening/closing member that reduces the calculation load for foreign material interference determination processing. A rotating speed detection sensor detects the rotating speed of a motor and provides its detection signal SP to a computer. The computer obtains a load determination rotating cycle t1 from the detection signal SP. Based on the load determination rotating cycle t1, the computer determines foreign material interference when it determines that the rotating speed is fluctuating due to a load that is the same as that produced when a foreign material is interfering with the opening/closing member and when the determination is made consecutively a predetermined number of times.

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 pulse width modulation circuit (10) for a motor controller is operated by generating an offset voltage and adding the offset voltage to a carrier timing signal to form an offset carrier timing signal. The operation of each of the phases of the motor is controlled as a function of the offset carrier signal.

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: In a motor and a disk drive apparatus using the motor, a switching control part produces a PWM pulse signal in response to the comparison result between a current detected signal and a command signal. An activate control part determines the active periods of power transistors in response to the holding state of the state holding part, and performs high-frequency switching operation to turn ON/OFF the power transistors in response to the PWM pulse signal of the switching control part. Furthermore, a voltage detecting part stops the detection of terminal voltages for a predetermined time in response to the PWM operation by the switching control part. After the stop, the voltage detecting part resumes the detection of the terminal voltages. This prevents improper detection caused by PWM noise.

Abstract: There is provided a DC motor control system and method which is capable of carrying out an accurate rotation control of a DC motor even when the power supply voltage thereof is reduced. A detection signal indicative of a detected number of rotations of the DC motor is delivered. Stop control is carried out for stopping the DC motor by braking rotation of the DC motor when the number of rotations of the DC motor indicated by the detection signal has reached a predetermined number of rotations.

Abstract: The pulse duration of voltage pulses for the control of a motor winding through power transistors is effected by writing data from a microprocessor or CPU to a module having intermediate register into which that data is written, the module then reading the data and effecting the modulation in a pulse by pulse manner.

Abstract: A controller using rectified AC voltage to drive a DC motor. A first rectified produces a waveform that passes through zero voltage in synchronization with the A.C. supply voltage. The first rectified voltage is applied to the D.C. motor. A second rectified voltage produces a waveform that passes through zero voltage in synchronization with the A.C. supply voltage. A circuit generating a unipolar waveform output voltage drives a switch that turns on and off the connection of the first rectified voltage to the D.C. motor. The on time can vary from zero to one half of the period of the AC voltage for maximum speed. The switching is synchronized with the unipolar waveform. The time on is varied by varying the pulse width driving the switching device.

Abstract: A device for driving a multi-phase d.c. motor (8) includes a multi-phase inverter (11) for supplying drive signals to the windings (2, 4, 6) of the motor. The multi-phase inverter (11) supplies a first and a second drive signal at a time to at least one winding (2) of the motor. The first and the second drive signal flow in opposite directions in the at least one winding (2). The device further has pulse-width modulators means (40.1-40.6) for applying a first pulse-width modulation to the first drive signal and a second pulse-width modulation to the second drive signal. The pulse-width modulation means (40.1-40.6) are adapted to vary the pulse-width of the pulse-width modulation in order to accelerate, actively decelerate or maintain the speed of the motor 8 and to select a direction of rotation of the motor.

Abstract: A disc drive includes an apparatus for limiting coil energization current to a programmable value. A current sensor is operatively coupled to a coil and provides a signal which is indicative of current flow through the coil. A configurable voltage source is responsive to a control signal. A current inhibitor is operatively coupled to the output of the current sensor and the voltage source such that the current inhibitor selectively inhibits current flow through the coil based on results of a comparison between the current sensor signal and a voltage supplied by the configurable voltage source. A method of calibrating a current control threshold is also provided as well as a method of controlling the coil energization current.

Abstract: The control of the current in a PWM mode through independently controlled windings of a multi-phase motor driven in a "bipolar" mode is implemented by employing only two sense resistors and related control loops. This is so regardless of the actual number of windings of the motor.

Abstract: In a multiple print head printer in which print heads are removable and exchangeable, a method of controlling a printer carriage motor comprises the steps of receiving a print job, the print job comprising print commands and print data, determining a type of print mode to print the print data based on the received print commands, detecting a number of print heads installed in the multiple print head printer, selecting a motor control function for controlling operational speed and direction of the printer carriage motor based on the determined type of print mode and the detected number of print heads.

Abstract: A motor controller controls motor rotational speed by repeatedly executing a sequence of operations. Initially, a pulse is generated that causes a predetermined fixed current to be supplied to the motor winding for a predetermined driving interval. The winding current is forced to zero after the pulse has occurred. A settling interval is allowed to pass in which the back EMF across the motor winding stabilizes, and then the winding back EMF is compared to a velocity command voltage representing the desired rotational speed of the motor. If at the end of the settling interval the back EMF is less than the velocity command voltage, indicating that the motor speed is less than the desired speed, then a new control cycle is begun, starting with the assertion of the current-driving pulse.

Abstract: A disc drive includes an apparatus for limiting coil energization current to a programmable value. A current sensor is operatively coupled to a coil and provides a signal which is indicative of current flow through the coil. A configurable voltage source is responsive to a control signal. A current inhibitor is operatively coupled to the output of the current sensor and the voltage source such that the current inhibitor selectively inhibits current flow through the coil based on results of a comparison between the current sensor signal and a voltage supplied by the configurable voltage source. A method of calibrating a current control threshold is also provided as well as a method of controlling the coil energization current.

Abstract: The motor control system is operable with multi-phase bipolar parallel winding brushless DC motor. The motor control system includes multi-phase bipolar H-bridge circuits which change current flow direction as the output signal from motor encoder changes. The motor control system is responsive to the speed control circuit to control speed and to the fault detection circuit to give maximum safety and control. The motor control system provides controlled phase signal to individually enable each phase of the stator windings to selectively control the speed of the motor. The motor control system also has a conventional pulse width modulation driver for providing power to the motor. The motor control system of the present invention utilizes both modes to fully utilize the motor's capabilities and at the same time saves power and reduces loading in each of the H-bridges driving stator windings.

Abstract: A distributed power supply for a motor controller including electronic control circuits for controlling IGBT power transistor stages. The power supplies for the power transistors and gate drivers therefor are isolated from the power supplies for the electronic control circuits. Each of the gate drivers for the IGBT power transistor is supplied through a separate floating supply. Power supplies for the digital components and the analog components have separate ground return paths and are tied together at the supplies.

Abstract: A controller controls the running speed of a variable speed motor of the type which runs at a speed related to the duty cycle of a pulse width modulated drive voltage applied to it and to the load being applied. The controller includes a setting switch for setting the motor running speed and a device for measuring the load being applied to the motor. Also included is a data storage for storing data representing a plurality of different pulse width modulation duty cycles for driving the motor at various desired motor running speeds and with various loads being applied to the motor. A processor is operatively connected to the setting switch, the load measuring device and the data storage for generating signals representing a particular duty cycle corresponding to a desired running speed setting and applied load to result in the desired motor speed. The processor generates these signals at a predetermined time interval to reach and maintain the desired motor speed.

Abstract: The invention relates to a method for driving an electric motor (1) which is employed, in particular, in manually guided electric tools, such as drilling machines, screwing machines or the like. Variable pulses of an electric voltage are applied to the electric motor (1) in such a way that the rotor of the electric motor (1) moves at a rotational speed which can be set. In order that the rotor of the electric motor (1) moves intermittently or abruptly, at least parts of at least individual pulses are blanked by superposition of a pulse interval having a zero voltage. A circuit arrangement for a method of this type has control electronics (5) and an electronic power switch (4), such as a triac, a transistor, an IGBT or the like, which is switched by the control electronics (5) in such a way that the variable pulses can be applied to the electric motor (1) via the electronic power switch (4).

Abstract: Masking of switching noise is implemented in the driving system of an "H" bridge stage by exploiting the periodic signal generated by a PWM control circuit (normally present in the control system for controlling the "H" bridge in an open-loop mode) for masking the decay time of the disturbances caused by the switching from off-to-on of a first pair of switches of the bridge that drive a current in a certain direction through the load. This is implemented by keeping high for a preset period of time the periodic signal generated by the PWM circuit and varying the duty-cycle of the signal for regulating the mask time in function of the load characteristics.

Abstract: Current control apparatus of DC motor includes current amplifying means for detecting the current amount at the rear end of the motor and amplifying the current value; on-off control means for comparing the input current with the current supplied from the current amplifying means and outputting an on-off control signal according to the current amount; and microcomputer for controlling the duty value of the pulse wave of a predetermined frequency occurring in accordance with the on-off control signal from the on-off control means and controlling the on-off time of the chopper transistor.

Abstract: A system for reducing Radio Frequency Interference (RFI) produced by motors which are powered by Pulse Width Modulation (PWM). It is believed that the PWM induces radiation at the PWM frequency and harmonics. The invention shields power cables which carry the PWM pulsed current, and provides capacitive shunting of one of the cables to ground.

Abstract: Switching and propagation delays in generating a PWM control signal by a circuit that generally includes an error amplifier, a sawtooth oscillator and a comparator for comparing the error signal with the sawtooth signal, is compensated by generating a second sawtooth signal synchronous with the master sawtooth signal but having a reduced discharge time and by applying the second synchronous sawtooth signal to the respective input of the PWM comparator.

Abstract: A brushless DC motor is controlled by determining a speed of the motor and a line voltage supplying drivers of the motor. Based upon these determined values and predetermined motor performance data, a maximum PWM on-time is determined for drive signals supplied to windings of the motor. This maximum PWM on-time thereby limits motor torque output to a predetermined maximum. Stopping the motor is performed in sequential phases including a loaded generator phase, an active braking phase and a holding phase. During holding, the amount of energy supplied to the motor is reduced to the point just before slippage such that holding energy is minimized. Upon power failure, the motor is driven toward a spring return home position overcoming static friction that may prevent the spring return mechanism from functioning properly. These techniques are applied to a motor in an actuator.

Abstract: A memory device, e.g. a capacitor, is provided for a collectorless DC motor. This component is charged whenever a particular rotor position is reached. In so doing, a voltage value or quantity on this memory device is changed. This quantity is compared to another quantity, which is dependent on a desired parameter, e.g. ambient temperature or gas or dust concentration. A reference signal is produced when a particular reference criterion is satisfied. The difference between the beginning of this reference signal and a second predetermined rotor position, which follows the initial predetermined rotor position with respect to time, is measured, and on the basis of this measurement, the current flow of the collectorless DC motor is influenced or regulated. In particular, the current can be toggled on and off as the rotor passes certain predetermined positions.

Abstract: A system for reducing Radio Frequency Interference (RFI) produced by motors which are powered by Pulse Width Modulation (PWM). It is believed that the PWM induces radiation at the PWM frequency and harmonics. The invention shields power cables which carry the PWM pulsed current, and provides capacitive shunting of one of the cables to ground.

Abstract: An electric motor has first and second power feed terminals. A power feed line connects a dc power supply and the electric motor. A switching element provided in the power feed line includes a MOS-FET having a gate subjected to a pulse width modulation signal with a controllable duty cycle. The switching element changes between its on state and its off state in response to the pulse width modulation signal. The first power feed terminal of the electric motor is connected to the switching element. A flywheel diode connected in parallel with the electric motor operates to absorb a voltage which appears across the electric motor and returning a current when the switching element changes to its off state. A capacitor connected between the gate of the switching element and the second power feed terminal of the electric motor operates to suppress radio-frequency noise occurring upon every change of the switching element between its on state and its off state.

Abstract: The present invention utilizes batteries in series addition and through controlled switching maintains current and voltage more constant as the batteries power a consuming device. The invention is described in its application to an electric motor powered wheeled vehicle and includes sensing means at the vehicles accelerator pedal and computer control to automatically control the power from a battery storage system to the electric motor efficiently and extend longevity of a battery powered vehicle.

Abstract: A method for reducing the amount of power dissipated in the internal resistance of a battery supplying current to a load through a circuit that switches the battery on and off at a known switching rate and duty ratio to result in ON periods during which the battery is coupled to the load and OFF periods during which the battery is not coupled to the load, includes the step of providing a bank of capacitors connected across the battery. The bank of capacitors has at least one capacitor, a combined equivalent series resistance less than the internal resistance of the battery, and a combined capacitance such that the product of the combined capacitance expressed in microfarads and the switching rate expressed in Hertz is at least 4.times.10.sup.6. The method proceeds by storing energy from the battery in the bank of capacitors during the OFF periods for contribution to the load during the ON periods.

Abstract: A motor drive control device which drives a motor in accordance with a pulse width modulated input signal, a first binary signal indicating a rotation direction for driving the motor and a second binary signal indicating whether drive of the motor is ON or OFF. The motor drive control device includes a logic circuit receiving the pulse width modulated input signal, the first binary signal and the second binary signal and, in response, producing a first pulse width modulated output signal and a second pulse width modulated output signal which together indicate a rotation direction and rotation speed for driving the motor.

Abstract: A method for reducing power supply current surges and power supply voltage noise in an electric motor control system. The method limits the rate of change of power to the motor. The rate of change of power is limited by microprocessor firmware. Use of firmware reduces the size and weight requirements of motor control hardware and power supply filtering hardware.

Abstract: A loading and unloading device for loading and unloading a head slider has an actuator driver circuit 11 for driving an actuator 3 with pulses. A counterelectromotive force generated by a voice coil of the actuator is detected when the pulses are off, and fed back to the actuator driver circuit 11 to enable the actuator driver circuit 11 to control the position and speed of the actuator. The speed at which the head slider is loaded and unloaded can thus be controlled into a desired value to minimize the danger of collision between a head and a disk.

Abstract: A control circuit adapted to control a motor includes a first circuit part for generating an excitation current to be supplied to the motor and having a predetermined period that is dependent on a predetermined rotation period of the motor, and a second circuit part for superimposing on the excitation current pulses having a period that is small compared to the predetermined period of the excitation current.

Abstract: A motor controller operable at a PWM (pulse width modulated) repetition rate above 6,000 Hz. A special saturable transformer with an interwinding capacitance of less than 5 picofarads is used to isolate the electronic control circuits from the power stage. PWM pulses are supplied to the saturable transformer such that the leading and trailing edges of the pulses pass through to a Schmitt trigger circuit which reconstructs the original pulse.

Abstract: A motor assembly includes a brushless dc motor and a driving unit. The driving unit includes three first power transistors, each being activable to connect a respective one of three windings of a coil unit of the dc motor and a power supplying circuit. A comparing unit compares a reference voltage signal equal to a desired motor speed from a speed setting unit with an analog voltage signal corresponding to the rotating speed of the rotor from a frequency-to-voltage converter and generates an analog error voltage signal. Each of three second power transistor corresponds to one of the first power transistors and is activable to connect the power supplying circuit and a respective one of the windings of the coil unit.

Abstract: A PLL system has a phase comparator for converting the phase difference between a reference clock signal and a feedback clock signal corresponding to a PWM signal Into a binary value, a frequency comparator for converting the frequency difference between the reference and feedback clock signals into a binary value, an automatic gain controller for adjusting the loop gain of the PLL system to a given value whenever the output of the frequency comparator reaches a change point, and a PWM signal generator for generating the PWM signal according to the outputs of the phase comparator, frequency comparator, and automatic gain controller. These components of the PLL system process digital signals, to simplify the structure of the PLL system, expand the range of loop gains to be set, and speedily synchronize the feedback clock signal with the reference clock signal.

Abstract: A general purpose or universal motor control is constructed as integrated circuit using a plurality of state machines and memories. The specific characteristics of a motor are programmed into a programmable "features" memory. A lookup table contains parameters for operating the motor that are accessed as a function of the features. The features memory and the lookup table may be programmed and tested through a communications state machine. External and internal pulse width modulation is provided along with dynamic braking as options that are utilized by the state machines depending upon the features. A multiplexer acts a switch between the state machines, the memories and the motor drive.

Abstract: A multiple output stepped compound voltage supply includes a field intensity control which enables a DC motor control circuit to provide continuous linear or pulse modulation control among the stepped voltages in relation to the voltage output.

Abstract: The present invention features a system for optimizing control of separately excited shunt-wound dc motors, where optimization is achieved through microprocessor-based independent PWM control of a chopper (armature) and an H-bridge (field). Connected to the armature is an armature voltage amplifier for varying the applied armature voltage. A field voltage amplifier is also provided for determining the direction of motor rotation and varying the voltage applied to the field winding. A first sensor is connected to the driven wheel(s) of the vehicle in order to determine the wheel rotational speed. A second sensor is connected to the armature circuit in order to determine the armature current. A third sensor is connected to the field circuit in order to determine the field current. A decoupling controller uses the wheel speed and armature current information, and adjusts the armature voltage and the field voltage.

Abstract: A device for PWM control of the printer carriage motor (1) which has a circuit (65) for generating a first PWM pulses of 100% duty ratio, a circuit for computing second PWM pulses (31, 37, 39, 15, 17, 53, 57, 59) according to the PI control method based on the difference between the motor current speed and the predetermined standard speed, and a circuit (121) for holding the optimum integrated value for controlling the motor current speed agree with the standard speed. Until the motor current speed reaches a predetermined transfer speed slightly lower than the standard speed, the carriage motor is accelerated with the maximum acceleration according to the first PWM pulses, when the transfer speed is reached, the optimum integrated value is set as the initial integrated value of the PI control, and thereafter the speed control is carried out according to the PI control method.

Abstract: The invention is a chopper control for electric cars. In the control device, the currents of the armatures A1 and A2 of electric car driving shunt motors connected to a power source L are controlled by first chopper devices CH1 and CH2, the currents, in the forward direction, the field coils SF1 and SF2 of the shunt motors are controlled by a second chopper device FCH1, and the currents, in the reverse direction, of the field coils are controlled by a third chopper coil FCH2.

Abstract: A switching circuit for varying rotational speed of a motor includes a power supply line for connecting the motor to a power source so as to supply driving power to the motor. A parallel connecting circuit of an on-off switch and a short circuiting switch is provided in the power supply line, in such a manner that the driving power is continuously supplied to the motor when the short circuiting switch is on, while in the case that the short circuiting switch is off, the driving power is supplied to the motor during on of the on-off switch but is not supplied during off of the on-off switch. A control member is provided for operation by an operator for varying rotational speed of the motor. The control member is operative for turning on the short circuiting switch at the maximum amount of its operation.

Abstract: A PWM circuit for generating a PWM wave which is pulse-width modulated in response to binary information and is used for a signal such as a motor driving signal in an R-DAT (rotary head type digital audio tape recorder) comprises a circuit for dividing binary information such as a motor speed error signal provided for generating a PWM wave into plural bit groups and generates PWM waves corresponding to numerical values of these plural bit groups, and a circuit for weighting the generated PWM waves in an analog manner at a ratio corresponding to orders of the respective bit groups and adding the weighted PWM waves. Since binary information is divided into plural bit groups, the bit number of each bit group is small so that the period of PWM wave can be shortened without reducing the quantization bit number of the binary information or shortening reference clock period whereby accuracy of an error signal can be improved when the invention is applied to, e.g., a motor drive device.