Sensorless stall detection for motors
First Claim
1. A motor system comprising:
- a motor; and
a detector which monitors a motor command voltage spectrum for the presence of at least one stall indicating harmonic.
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Accused Products
Abstract
Motor stall can be detected without the use of additional sensors in a hybrid stepper motor through the detection of a harmonic component an associated motor spectrum. The associate motor spectrum can be a motor command voltage spectrum. For example, all of the harmonic components except for the second harmonic are eliminated from the voltage and the presence or lack thereof indicates whether or not the motor has stalled. The harmonic component can be isolated with the use of several cascaded filters. These filters can include notch filters and bandpass filters. Additionally, the circuit may be realized as either an analog, digital or hybrid circuit. The motor may be either hybrid stepper motor having 2, 3, or 5 phases, or a variable reluctance motor.
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Citations
20 Claims
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1. A motor system comprising:
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a motor; and
a detector which monitors a motor command voltage spectrum for the presence of at least one stall indicating harmonic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A stall detector for an open loop motor system, said stall detector comprising:
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a motor driver for supplying a command voltage signal to a motor; and
a stall detector monitor which monitors the command voltage signal and detects a stall condition as a function of the presence of at least one even harmonic component of the command voltage signal supplied to the motor. - View Dependent Claims (15)
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16. A method of stall detection in a motor comprising:
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monitoring at least one stall indicating harmonic associated with a motor command voltage spectrum; and
determining whether the motor has stalled as a function of the at least one stall indicating harmonic. - View Dependent Claims (17, 18, 19, 20)
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Specification