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5871 results about "DC motor" patented technology

A DC motor is any of a class of rotary electrical machines that converts direct current electrical energy into mechanical energy. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current flow in part of the motor.

Method and apparatus for controlling brushless DC motors in implantable medical devices

Methods and apparatus for controlling a polyphase motor in implantable medical device applications are provided. In one embodiment, the polyphase motor is a brushless DC motor. The back emf of a selected phase of the motor is sampled while a drive voltage of the selected phase is substantially zero. Various embodiments utilize sinusoidal or trapezoidal drive voltages. The sampled back emf provides an error signal indicative of the positional error of the rotor. In one embodiment, the sampled back emf is normalized with respect to a commanded angular velocity of the rotor to provide an error signal proportional only to the positional error of the motor rotor. The error signal is provided as feedback to control a frequency of the drive voltage. A speed control generates a speed control signal corresponding to a difference between a commanded angular velocity and an angular velocity inferred from the frequency of the drive voltage. The speed control signal is provided as feedback to control an amplitude of the drive voltage. In one embodiment, an apparatus includes a brushless DC motor and a commutation control. The commutation control provides a commutation control signal for a selected phase of the motor in accordance with a sampled back electromotive force (emf) of that phase. The back emf of the phase is sampled only while the corresponding drive voltage for the selected phase is substantially zero, wherein a frequency of a drive voltage of the motor is varied in accordance with the commutation control signal.
Owner:HEARTWARE INC

Integrated magnetic bearing

The present invention provides a rotational magnetic gimbal with an integral magnetic bearing. Brushless DC motor technology provides electromagnetic suspension, using a single electromagnetic actuator to perform both the radial bearing and rotary torque (motoring) functions. An integrated motor and magnetic bearing consistent with the invention comprises a rotor comprising a plurality of permanent magnets and a stator comprising a plurality of independently controlled coil segments magnetically coupled to the permanent magnets. Embodiments may further comprise first and second radial position sensors, the first radial position sensor disposed in or adjacent to a clearance gap between the rotor and the stator for sensing the position of the rotor with respect to the stator along a first axis, and a second radial position sensor disposed in or adjacent to the clearance gap between the rotor and the stator for sensing the position of the rotor with respect to the stator along a second axis. In method form, a method for providing integral electromagnetic motor and bearing functions comprises sensing a first radial position of a rotor, the rotor comprising a plurality of permanent magnets, with respect to a stator along a first axis, the stator comprising a plurality of independently controlled coil segments magnetically coupled to the permanent magnets; and sensing a second radial position of the rotor with respect to the stator along a second axis; and delivering current to at least one coil segment, the amount of current based on at least one sensed position.
Owner:AIREX CORP

Gear pump for micro-miniature turbojet engine

The invention discloses a gear pump used for a microminiature turbo-jet engine, comprising a direct current motor, a pump body, an upper pump cover, a lower pump cover, a shell, a pair of driving and driven gears which are meshed and a driving shaft and a driven shaft. The driving gear is arranged on the driving shaft; the driven gear is arranged on the driven shaft and is aligned and meshed withthe driving gear; the lower pump cover is fixed on the direct current motor, the upper pump cover is connected to the lower pump cover and the plane of the pump body is pressed tightly and sealed so as to lead the structure to be simple; the shell is sleeved at the outside of the lower pump cover; the driving gear and the driving shaft adopt a method of combining clearance fit and a transmission pin to eliminate the installation error of an output shaft of the direct current motor; and an antifriction material is embedded at the positions on the lower pump cover and the upper pump cover corresponding to the driving gear and the driven gear so as to increase the reliability and durability of the gear pump. Most parts of the gear pump adopt aluminium alloy so as to reduce the weight furthest. The gear pump can control the rotating speed of the direct current motor by pulse-width modulation of a single-chip microcontroller and control the flow rate of the gear pump precisely.
Owner:北京领动国创科技有限公司

Position sensor-free double closed-loop speed regulation control method for brushless DC motor

InactiveCN103248294AAccurate control of different speedsSolve the problems of large volume and low speed accuracyTorque ripple controlSingle motor speed/torque controlClosed loopEngineering
A position sensor-free double closed-loop speed regulation control method for a brushless DC motor comprises the following steps: (1) initializing functional modules and peripherals; (2) opening AD (Analog-Digital) interruption and protection interruption; (3) detecting the start key of the motor, judging whether to start the motor, if yes, executing the next step, and if not, continuing to execute the step; (4) starting voltage detection, judging whether the voltage of a main circuit is larger than starting voltage, if yes, executing the next step, and if not, returning to the step (3); (5) entering a motor starting subprogram and beginning operating the motor; (6) entering a double closed-loop speed regulation subprogram, and regulating the rotational speed and the current of the motor according to voltage value; and (7) detecting a motor brake key, judging whether to press the key, if yes, entering a motor brake subprogram, and if not, returning to the step (3). The method provided by the invention overcomes the defects of larger size, low rotational speed accuracy and the like of the conventional motor controller, can accurately control different rotational speeds of the motor, and can simultaneously realize counter electromotive force zero-cross comparison position sensor-free reversing and Hall position signal reversing.
Owner:TIANJIN UNIV
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