5208results about "Synchronous motors starters" patented technology

Brushed DC electric motors have a rotor with commutator portions moving into and out of contact with brushes. As each of these contacts end, a back EMF force is induced into a main current supply signal. The number of these periodic forces can be counted and utilized to identify the position of the component being rotated by the DC electric motor. This method is relatively insensitive to environmental changes, and thus more accurate than the existing art.

A permanent magnet DC brushless motor control assembly permits a user to select the permanent magnet DC brushless motor operating characteristics by selecting appropriate control circuits to interface with the motor. The assembly includes a permanent magnet DC brushless motor, a commutator electrically coupled to the motor, and at least one control module electrically coupled to the commutator, to control operating characteristics of the permanent magnet DC brushless motor.

A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference Δθ between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position. A high-efficiency motor drive unit with improved maintainability of rotary sensor and improved accuracy of sensing the magnet pole position of a permanent magnet synchronous motor that accelerates and decelerates very quickly in a wide range of speed is realized.

In a motor, a stationary member is provided with a number M (M is a positive integer) of first poles within 360 electrical degrees at spaces therebetween. A plurality of windings are at least partly wound in the spaces, respectively. A movable member is movably arranged relative to the stationary member and provided with a number K (K is a positive integer) of second poles. The number K of second poles is different from the number M of first poles. A unidirectional current supply unit supplies a unidirectional current to at least one of the windings so as to create an attractive force between at least one of the first poles and a corresponding at least one of the second poles to thereby move the movable member relative to the stationary member.

A motor control system for a brushless and sensorless DC motor for driving a compressor, pump or other application, includes a protection and fault detection circuit for detecting a locked rotor and a rotor which has stopped because of lost rotor phase lock. The motor control system also includes an off-the-shelf motor control integrated circuit having an input for disabling power outputs to the motor phase coils. The protection and fault detection circuit uses a back EMF sampling circuit coupled to the motor phase coils and momentarily disables power to the motor phase coils, via the motor control integrated circuit input, to determine if the motor rotor is rotating. The system also monitors supply voltage, supply current, temperature, and motor speed limits to detect faults and protect system components.

A permanent magnetically excited electrical rotary drive for a blood pump is proposed, comprising a permanent magnetic rotor and a stator, said stator comprising a drive winding having at least two loops for the production of a magnetic drive field which produces a torque on the rotor, with each loop belonging to a different electrical phase, furthermore comprising a setting device which supplies each loop in each case with a phase current or in each case with a phase voltage as a setting parameter, with the setting device comprising a separate power amplifier for each loop so that the setting parameter for each loop can be regulated independently of the setting parameter for the other loops.

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.

A disk drive is disclosed comprising a spindle motor for rotating a disk, wherein the current applied to the spindle motor is controlled by adjusting a duty cycle of a pulse width modulated (PWM) signal. A current sensor generates a current sense signal representing a current flowing from a supply voltage. The current sense signal is integrated to generate an integration signal. The integration signal is compared to a threshold, and the result of the comparison is used to adjust the duty cycle of the PWM signal. In this manner the disk drive draws essentially constant average input current from the supply voltage which decreases the spin up time of the disk.

A disk drive is disclosed comprising a disk, a head actuated over the disk, and a spindle motor for rotating the disk, the spindle motor comprising a plurality of windings. Disk control circuitry executes a spin-down operation of the spindle motor by estimating an angular position of the spindle motor by applying a voltage to at least one of the windings and evaluating a rise time of current flowing through the winding. The windings are commutated in response to the estimated angular position, and a driving current is applied to the windings to brake the spindle motor.

A power electronics device for controlling an electric machine including a power section arranged within a housing which can be closed via a cover element. The power section has a plurality of capacitors and a plurality of power semiconductors which are connected to a power bus bar. In addition, a control device is provided for controlling the power electronics device. The capacitors, power semiconductors, and control device are cooled via a cooling device which is formed as a profile having an essentially U-shaped cross section. The cooling device has two lateral limbs and a base region through which cooling ducts are arranged. A suitable cooling medium flows through the cooling ducts and the ends of the cooling ducts opposite the housing cover are closed by a covering element. The capacitors, the power semiconductors and the control device are connected to the cooling device such that thermal exchange occurs between these components and the cooling device.

Power conversion apparatus and methods are presented for providing electrical power to a grid or other load in which a synchronous machine is driven by a wind turbine or other prime mover to provide generator power to a switching type current source converter (CSC), with a current source rectifier (CSR) of the CSC being switched to provide d-axis control of the synchronous machine current based on grid power factor feedback, and with a current source inverter (CSI) of the CSC being switched to provide leading firing angle control and selective employment of dumping resists to dissipate excess generator energy in a fault mode when a grid voltage drops below a predetermined level.

The speed of a fan motor is controlled by varying a DC voltage to the fan motor. A series pass transistor is used to vary the DC voltage to the fan motor. A power management controller sets the fan motor speed by outputting pulses to a pulse-to-DC voltage converter that changes the pulses to a proportional DC control voltage for controlling the series pass transistor. A tachometer output amplifier circuit is used to remove DC components and amplify to useful logic levels a low level tachometer output signal from the fan motor. The amplified tachometer signal is used by the power management controller in controlling the rotational speed of the fan motor.

A power tool that includes a brushless DC motor, one or more motor sensors, and a controller, such as, for example, an electronic speed control (ESC) circuit. The controller is adapted to provide instructions to control the operation of one or more parameters of the brushless DC motor. The controller is also adapted to receive feedback from one or more motor sensors that reflect whether the motor is attaining the one or more parameters. The controller may also be adapted to have a learning mode, in which feedback provided during use of the power tool is stored by the controller as a program so that the same operating parameters may be subsequently replicated by using the program to operate the tool. The controller may also use the feedback to adjust the operation of the motor so that the motor maintains one or more selected or programed operating parameters.