Methods and apparatus for motor startup with sinusoidal phase current
AssigneeAllegro MicroSystems, LLC
InventorsYisong Lu, Lyndon Ambruson
Life of this patent
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Abstract
Methods and apparatus for controlling a three-phase motor and providing sinusoidal phase currents during startup. In embodiments, differential outputs from a magnetic field sensing element are used to generate a polarity signal used to provide a motor direction drive signal. An amplitude signal derived from the magnetic field sensing element and a measured motor current are used to generate a current amplitude signal. A PWM module generates signals for driving the motor with sinusoidal phase currents from the current amplitude signal and the motor direction drive signal.
Claims32
A method for three-phase motor startup, comprising:
- receiving differential outputs from a magnetic field sensing element;
- generating a polarity signal from the differential outputs;
- receiving the differential outputs and generating an amplitude signal;
- generating a motor direction drive signal from the polarity signal;
- and
- generating sinusoidal motor drive signals during the motor startup from a measured motor current signal and the amplitude signal, wherein the motor drive signals drive the motor in a direction corresponding to the motor direction drive signal.
A motor controller system comprising:
- a control module configured to receive polarity information generated from differential outputs that are output by a magnetic field sensing element positioned in relation to phases of a three-phase motor and amplitude information generated from the differential outputs that are output by the magnetic field sensing element, the control module configured to generate a motor driving direction signal corresponding to the received polarity information and to generate an amplitude control signal from the amplitude information and a measured motor current information;
- and
- a pulse width modulation (PWM) module configured to receive the amplitude control signal and the motor driving direction signal and generate control signals for switching elements driving the motor that provide sinusoidal phase currents to the motor during startup, wherein the motor drive signals drive the motor in a direction corresponding to the motor direction drive signal.
A motor controller system comprising:
- a control means for receiving polarity information generated from differential outputs that are output by a magnetic field sensing element positioned in relation to phases of a three-phase motor and amplitude information generated from the differential outputs that are output by the magnetic field sensing element, and to generate a motor driving direction signal corresponding to the received polarity information and to generate an amplitude control signal from the amplitude information and the motor current information;
- and
- a pulse width modulation (PWM) means for receiving the amplitude control signal and the motor driving direction signal and generate control signals for switching elements driving the motor that provide sinusoidal phase currents to the motor during startup, wherein the motor drive signals drive the motor in a direction corresponding to the motor direction drive signal.
Dependencies are inferred from the claim text.