Abstract: A method of controlling a DC motor that includes the step of providing a pulse-width modulation (PWM) signal to the DC motor. The PWM signal provides a voltage to operate the DC motor. The method also includes the steps of measuring a voltage generated by the DC motor when the PWM signal is off. In more particular embodiments, the method includes measuring a current being supplied to the DC motor when the PWM signal is off. The method may further require determining a motor speed of the DC motor based on the measured voltage. The method further includes controlling the DC motor to maintain a relatively constant motor speed with varying loads on the DC motor.

Abstract: Devices, systems, and methods for varying rotational speeds is disclosed. A battery pack has a plurality of batteries and a switch. The battery pack has an overall voltage. The switch varies the overall voltage in discrete steps by combining the plurality of batteries in series, in parallel, or in a combination thereof. A motor drives a shaft at a rotational speed. The motor is powered by the battery pack. The rotational speed varies proportionally with the overall voltage.

Abstract: A method of controlling a DC motor that includes the step of providing a pulse-width modulation (PWM) signal to the DC motor. The PWM signal provides a voltage to operate the DC motor. The method also includes the steps of measuring a voltage generated by the DC motor when the PWM signal is off. In more particular embodiments, the method includes measuring a current being supplied to the DC motor when the PWM signal is off. The method may further require determining a motor speed of the DC motor based on the measured voltage. The method further includes controlling the DC motor to maintain a relatively constant motor speed with varying loads on the DC motor.

Abstract: A rotation speed control circuit is disclosed. The rotation speed control circuit includes a temperature-controlled voltage duty generator, a pulse-width signal duty generator, a multiplier and a rotation speed signal generator. The temperature-controlled voltage duty generator converts temperature-controlled voltage to digital temperature-controlled voltage and executes linear interpolation operation according to a first setting data so as to output temperature-controlled voltage duty signal. The pulse-width signal duty generator coverts pulse-width input signal to a digital pulse-width input signal and executes linear interpolation operation according to a second setting data so as to output a pulse-width duty signal. The temperature-controlled voltage duty signal and the pulse-width duty signal are executed for multiplication by the multiplier so as to output mixing-duty signal.

Abstract: A motor control apparatus that controls a DC motor includes a detection unit configured to detect angular speed of the DC motor, a driven member configured to be driven by the DC motor, and a control unit configured to increase, when starting to drive the DC motor, a control value for controlling driving of the DC motor from a first control value to a second control value at a predetermined increase rate, wherein the control unit detects a start-up characteristic of the DC motor based on a detection result of the detection unit, and corrects the first control value or the increase rate according to a result of comparing a detected start-up characteristic and a predetermined start-up characteristic such that the start-up characteristic of the DC motor becomes closer to the predetermined start-up characteristic.

Abstract: A method of controlling in-rush current to a DC motor is disclosed. The method may include operating the DC motor in a first mode including applying back-EMF across a relay coil to maintain the relay in an open configuration when the back-EMF is below a predetermined voltage. The method may also include operating the DC motor in a second mode including applying the back-EMF across the relay coil to maintain the relay in a closed configuration when the back-EMF is equal to or above the predetermined voltage.

Abstract: Information indicative of the placement of spindle motor components may be obtained and used to provide a correction to one or more BEMF-derived attributes used to control the spindle speed. In some implementations, first and second signals indicative of BEMF of different stator windings may be used to determine a speed-related characteristic. The speed related characteristic may be used to determine an error amount, which may be used to determine a correction factor to control the speed of the spindle motor.

Abstract: A drive control device is provided with a determining section and a voltage increasing section. The determining section determines if the actual acceleration is deficient in comparison with the acceleration requested by the driver or if the generator output is deficient in comparison with the acceleration requested by the driver. The voltage increasing section increases the voltage supplied to the electric generator from a vehicle mounted electric power source when the determining section determines that the actual acceleration or the generator output is deficient. As a result, the generator output deficiency is eliminated and the required motor torque is produced, thereby enabling the vehicle to start into motion appropriately in accordance with the acceleration requested by the driver.

Abstract: Information indicative of the placement of spindle motor components may be obtained and used to provide a correction to one or more BEMF-derived attributes used to control the spindle speed. In some implementations, first and second signals indicative of BEMF of different stator windings may be used to determine a speed-related characteristic. The speed related characteristic may be used to determine an error amount, which may be used to determine a correction factor to control the speed of the spindle motor.

Abstract: A control apparatus for an image forming apparatus to control a DC motor at low speed using a low resolution encoder and a method thereof. If the encoder does not generate any pulses during a controlling period, the control apparatus estimates the speed of the DC motor using a formula model related to a plant in which an output speed of the direct current motor is varied according to an input voltage and a ripple model to estimate the speed of the direct current motor due to a load ripple caused by a gear driven by the direct current motor. The control apparatus avoids additional costs associated with high resolution encoders and strongly resists variation of load and has an excellent control performance.

Abstract: A speed control apparatus includes a speed control part 12 for generating a source current command based on a difference between a speed command of a motor 4 and speed detection in which a speed of the motor 4 for driving a load 2 is detected, a notch filter 14 which can break a notch frequency resulting in a predetermined frequency selected among continuous frequency band widths and also generates a compensating current command in which the notch frequency is eliminated from the source current command signal, a notch filter adaptive part 16 for selecting the notch frequency so that the compensating current command in which a sustained vibration frequency component of the source current command is eliminated is generated from the notch filter 14, a subtracter 103 for generating an elimination portion current command resulting in a difference between the source current command and the compensating current command, and an adder 109 for adding the compensating current command and the elimination portion current

Abstract: A device for correcting a digital estimate of an electric signal is described. The device includes a comparator that generates a current proportional to the difference between an analog estimate signal, which derives from the digital estimate, and the electric signal. The device also includes a capacitor positioned to be charged by the current, a transistor that discharges the capacitor, and a comparator that compares the voltage at the terminal of the capacitor with a reference voltage. The device also includes a controller that drives the transistor in response to the output signal of the comparator and a logic device that generates a correction digital signal to be added to or subtracted from the digital estimate of the electric signal in correspondence of an ascending or descending waveform of the electric signal.

Abstract: A system and method for measuring fluid flow rate in a system where fluid is pumped, such as a gas monitoring instrument where gas is pumped from a space such as a room or enclosure through a conduit to a sensor. The flow of gas through a pump is determined by measuring motor back-e.m.f. which is proportional to motor speed. In a system where motor speed is regulated by pulse width modulation of the motor drive voltage, the back-e.m.f. is sampled during intervals between the drive pulses applied to the motor, and in a further aspect the sampling is done at selected, spaced-apart or infrequent intervals such as once for every ten or once for every hundred motor drive pulses. Advantageously, in an instrument that uses a microprocessor and analog-to-digital converter to measure gas-concentration, the same microprocessor and converter can provide the PWM control of the pump, in response to the back-e.m.f. generated by the pump motor between the drive pulses.

Abstract: Systems and methods are provided through which the current to a spindle motor of the recording medium of a mass storage device is modulated to avoid anomalies in the operation of mass storage device and reduce power consumption. In the example of a disc drive, the current is modulated to prevent expected or predicted disturbances in the air bearing between a read/write head and the recording medium, and to reduce the power consumption when no disturbances are predicted or expected.

Abstract: An apparatus (10) for controlling an electric motor (36) having a plurality of motor phases includes a motor controller (32) that controls energization of each phase of the plurality of motor phases. A compensation circuit (56, 84, 104) is associated with each phase of the plurality of motor phases. The compensation circuit (56, 84) of one phase of the plurality of motor phases adjusts a control parameter of another phase of the plurality of motor phases an amount functionally related to an electrical characteristic of the one phase in response to determining a diminished operating characteristic of the one phase.

Abstract: A vector control method is provided for controlling a rotor speed of an induction motor by an inverter which provides an AC current of varying frequency to the induction motor, and a vector controller which provides control voltage Vu, Vv, Vw, in response to an excitation current command i.sub.1d*. The excitation current command is indicative of an excitation current being fed to the induction motor, a desired rotation speed command .omega..sub.r*, and a primary frequency .omega., for controlling the inverter to vary the rotor speed. The method includes the steps of detecting a primary current being fed to the induction motor, analyzing the detected primary current to obtain an excitation current i.sub.1d and a detected torque current i.sub.1q, multiplying a torque value represented by the detected torque current i.sub.1q by a predetermined motor constant K.sub.m to obtain a slip frequency .omega..sub.s, and adding the obtained slip frequency .omega..sub.s to the rotation speed command .omega..sub.

Abstract: A motor control system for controlling operation of an electric motor associated with a motor-operated vent in a vehicle. The system monitors and stores data relating to the operating current and detects occurrences of abnormal loads applied to the vent by determining whether the monitored operating current exceeds one of several predetermined thresholds. The predetermined thresholds are dynamically modified in accordance with monitored condition variations of the operating current. The dynamically modified thresholds are initially based on either a value associated with the stall current of the vent motor or the start spike current of the vent motor. In addition, an embodiment is provided for monitoring and storing data relating to ripple current waves associated with the operating current, so that occurrences of abnormal loads may be detected by determining whether the frequency of the monitored ripple current waves is less than a predetermined value.

Abstract: A circuit for sensing the current delivered to a load, or multiple loads, such presented by a polyphase DC motor, without significantly dissipating the energy delivered to the load, has a predriver circuit and a power delivery circuit for each load. The predriver circuit is connected in a series path between a voltage source and a control element of the power delivery circuit, and the power delivery circuit is connected between a connection node and a respective one of the loads. A sensing element is connected in a series path between the source of voltage and the power delivery circuit connection node. In a preferred embodiment, the sensing element is a resistor, the predriver circuit is a PNP transistor, and the power delivery circuit is an NPN transistor. The PNP and NPN transistors are connected to form a pseudo-Darlington transistor pair, with the collectors of the NPN transistors interconnected to enable a single sense resistor to be used to sense the current in each of the loads.

Abstract: A motor control system for controlling operation of an electric motor associated with a motor-operated vent in a vehicle. The system monitors and stores data relating to the operating current and detects occurrences of abnormal loads applied to the vent by determining whether the monitored operating current exceeds one of several predetermined thresholds. The predetermined thresholds are dynamically modified in accordance with monitored condition variations of the operating current. The dynamically modified thresholds are initially based on either a value associated with the stall current of the vent motor or the start spike current of the vent motor. In addition, an embodiment is provided for monitoring and storing data relating to ripple current waves associated with the operating current, so that occurrences of abnormal loads may be detected by determining whether the frequency of the monitored ripple current waves is less than a predetermined value.

Abstract: A pulse width modulation control circuit includes a pulse width modulator which supplies a signal to a power switch tying together a DC signal generator and a motor and various sensing circuit including a control voltage disabler circuit. All of the sensing circuits are appropriately designed to ensure that the various components of the circuit are not damaged under abnormal conditions whether due to motor loads heavier than rated or undesired changes in AC current input or control voltages.

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.