Microsemi Soc Corporation

Ashwin Murali

Prakash Reddy

Battu Prakash Reddy

Pinninti Arjun

A method for controlling the drive current in a stepper motor includes measuring stepper motor current, computing a load angle of the stepper motor, calculating a torque ratio of the stepper motor, generating a reference current as a function of the torque ratio and a maximum current setting for the stepper motor, and setting the drive current of the stepper motor as a function of the reference current.

Apparatus and method for sensorless detection of load torque of a stepper motor and for optimizing drive current for efficient operation

A method for detecting failure of speed measurement of a multi-phase AC motor includes (1) sensing current drawn by the motor, (2) sensing voltage magnitude supplied to the motor, (3) measuring motor speed, (4) calculating motor speed, (5) determining whether the difference between the measured motor speed and the calculated motor speed is greater than a predetermined threshold, if the difference between the measured motor speed and the calculated motor speed is not greater than a predetermined threshold, repeating (1) through (5), if the difference between the measured motor speed and the calculated motor speed is greater than a predetermined threshold, indicating a fault, if a fault is indicated, performing a predetermined number of restart attempts, if the motor is successfully restarted, repeating (1) through (5), if the motor is not successfully restarted, indicating a restart failure.

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Hyderabad Telangana, India

Ashwin Murali