3966results about "Field or armature current control" patented technology

A powered surgical tool with a housing that contains a power generating unit such as a motor. A control module is disposed in a shell that is mounted in the housing. The control module contains a control circuit for regulating the actuation of the power generating unit. The power generating unit emits a signal representative of the operating state of the unit that is transmitted through the structural material forming the shell. Also internal to the control module shell is a sensor that monitors the signal emitted by the power generating unit. This signal output by the sensor is applied to the control circuit. The control circuit, based on the sensor signal regulates actuation of the power generating unit. Wherein the power generating unit is a motor, the signal emitted is the magnetic field that varies with rotor position. The sensor monitors the strength of this field.

In a method for operating a power tool with an energy accumulator, in particular a rechargeable energy accumulator, which supplies power to an electric drive motor, a clock frequency is generated by an electronic unit, with which a gate of a MOSFET—which supplies operating voltage to the drive motor—is switched on with each cycle, and a switching-off of the MOSFET is carried out within one cycle using different signals, as a function of operating parameters.

A motor control device selectively turns on or off a drive transistor in-accordance with a PWM control signal Sp, such that a drive current Im supplied to a motor is adjusted. The device also samples and holds a motor current Sm for obtaining a motor current value Ih. With reference to the motor current value Ih, the device protects the motor from an overcurrent. Sampling and holding of the motor current Sm is performed for a sampling and holding time Ts. The sampling and holding time Ts corresponds to a time period between a first point in time when the level of the PWM control signal Sp is switched for turning off the drive transistor and a second point in time that precedes the first point in time by a predetermined period. As a result, the motor current value Ih is detected with high accuracy.

The present invention relates to a method for control of a direct current motor in one or several fan units, each comprising a fan, which method comprises: generation of a control signal from a first control unit which is external in relation to the said fan unit; transmission of the said control signal to the said fan unit; reception of the transmitted control signal in the said fan unit; interpretation of the said control signal in a second control unit which is arranged in association with the said fan unit; and generation, in the said second control unit, of a supply signal for the said direct current motor, on the basis of the control signal generated by the first control unit and received in the fan unit and on the basis of a supply voltage. According to the invention, the method comprises transmission of the control signal together with the supply voltage over a shared communication link, with the control signal being superposed on the supply voltage. The invention also relates to an arrangement for such control. By means of the invention, improved control is obtained of a motor that can be utilized in a ventilated seat in a vehicle.

A method of controlling a motorized window treatment provides for continued operation of the motorized window treatment during an overload or low-line condition. The motorized window treatment is driven by an electronic drive unit having a motor, a motor drive circuit, and a controller. The controller controls the motor drive circuit to drive the motor with a pulse-width modulated signal generated from a bus voltage. The controller is operable to monitor the magnitude of the bus voltage. If the bus voltage drops below a first voltage threshold, the controller stops the motor or reduces the duty cycle of the pulse-width modulated signal to allow the bus voltage to increase to an acceptable magnitude. When the bus voltage rises above a second voltage threshold, the controller begins driving the motor normally once again. During an overload or low-line condition, the controller is prevented from resetting, while driving the motor with minimal interruption to the movement of the motorized window treatment.

A method for controlling an electric motor. A desired speed is identified for the electric motor during operation of the electric motor. A voltage is identified to cause the electric motor to turn at the desired speed. The voltage is applied to the electric motor and actively controlled during operation of the electric motor.

A soft start circuit generates a soft start voltage which changes over time when light emission of an EEFL is started. A pulse modulator receives a feedback voltage that corresponds to the output voltage of an inverter and the soft start voltage, and adjusts the duty ratio of a pulse signal PWM such that these two voltages match one another using a feedback operation. A striking control circuit monitors an error signal which is asserted when an abnormal state occurs. In a case in which the error signal has been asserted at a detection timing after the soft start voltage has reached a target voltage, the striking control circuit resets and restarts the soft start circuit. A driver controls the switching of the voltage at the primary coil of a transformer according to the pulse signal received from the pulse modulator.

An end effector includes first and second jaw members moveable relative to one another. Each of the first and second jaw members including a tissue contacting surface opposing the tissue contacting surface of the other jaw member. The end effector includes a detection assembly that is disposed within the first or second jaw member that is configured to detect an attribute of tissue between the first and second jaw members. The detection assembly may include a light source configured to emit light towards tissue between the first and second jaw members or may include an ultrasound transducer configured to emit ultrasound energy towards tissue between the first and second jaw members.

A surgical stapler includes a handle assembly, an end effector, a firing rod disposed in mechanical cooperation with the end effector, a drive motor coupled to the firing rod, a sensor, and a controller. The end effector includes a first and second jaw member moveable relative to one another. The first jaw member includes a surgical fastener and the second jaw member includes an anvil. The drive motor is configured to advance the firing rod to cause the first and second jaw members to clamp tissue and to eject a surgical fastener. The surgical stapler includes a sensor that is configured measure a clamping force exerted on tissue by the first and second jaw members. The controller control a speed of the drive motor based on the measured clamping force.

An end effector includes first and second jaw members moveable relative to one another. Each of the first and second jaw members including a tissue contacting surface opposing the tissue contacting surface of the other jaw member. The end effector includes a detection assembly that is disposed within the first or second jaw member that is configured to detect an attribute of tissue between the first and second jaw members. The detection assembly may include a light source configured to emit light towards tissue between the first and second jaw members or may include an ultrasound transducer configured to emit ultrasound energy towards tissue between the first and second jaw members.

A control circuit for a DC motor, has: a first and second input ports for connection to a DC source; a H-bridge driving circuit, having first and second switches connected in series between the input ports, and third and fourth switches connected in series between the input ports, a first output port between the first and second switches and a second output port between the third and fourth switches, and a shunt circuit and / or a blocking circuit. The motor is connected between the first and second output ports. The shunt circuit is connected between the first second output ports and has a resistance that will decrease in response to BEMF generated by the motor. The blocking circuit is connected in series with the motor between the output ports and has a resistance that increases in response to BEMF generated by the motor.

A cordless power tool may include tool identification circuitry to provide a tool identification signal to a battery pack. The tool identification signal may be representative of data particular to the cordless power tool. A method may include coupling a battery pack to a cordless power tool, and providing a tool identification signal to the battery pack from the cordless power tool once the battery pack is coupled to the cordless power tool, the tool identification signal representative of data particular to the cordless power tool.

An arrangement is disclosed for controlling fan motors in fan-powered terminal units which permit the air flow of the terminal units to be factory preset and reset using a voltmeter. The fan motor is responsive to the pulse width of pulses of a pulse width modulated signal to provide an air flow which is proportional to the pulse width. By adjusting the pulse width, the air flow may be set as desired. A pulse width modulated signal having pulses with a set amplitude and frequency is generated. The dc voltage of the pulse width modulated signal is measured using a voltmeter. As the pulses have a set amplitude and frequency, the pulse width of the pulses may be adjusted by controlling the dc voltage of the pulse width modulated signal. The fan motor is programmed to deliver the set air flow over a range of static pressures.

A change-over device of pull cord control and wireless remote control for a DC brushless-motor ceiling fan is to have a driver installed in a ceiling fan basic body, and the driver has a detecting unit for detecting whether or not a connector positioned in a hanging bell is connected with a wireless control switch unit so as to control the blades of the DC brushless-motor ceiling fan to rotate by pull cord control or by wireless remote control. Further, the connector is installed inside the hanging bell; therefore, when the DC brushless-motor ceiling fan is to be additionally provided with a wireless control switch unit, it is convenient and safe in installation.

A driving apparatus for a DC brushless motor of a ceiling fan is provided. By setting at least one coder and one sensor outside the DC brushless motor, the driving apparatus can sense the position of magnetic poles of the motor for driving the motor. Meanwhile, a controller set with the motor stores the rotation speed of the motor before being turned off by detecting the turn-off time of a turn-on / off signal.

A display apparatus may include touch detection circuitry including a light sensing circuit and a physical parameter sensing circuit (e.g., a pressure sensing circuit). The display apparatus may further include processing circuitry implementing a power-saving mode and a normal mode, and configured to generate touch information. An display driver may include a photo sensing circuit and a pressure sensing circuit. An embodiment of the display driver may include: an amplifying unit amplifying a photo sensing signal and a pressure sensing signal; a parallel-to-serial converting unit converting the amplified photo sensing signal and the amplified pressure sensing signal into serial sensing signals; and an analog-to-digital converter converting the serial sensing signals into digital sensing signals, wherein the amplifying unit, the parallel-to-serial converting unit, and the analog-to-digital converter operate in one of a normal mode and a power saving mode according to the pressure sensing signal.