ACCURATE ROTOR POSITION SENSOR, METHOD USING MAGNET RING ANDLINEAR OUTPUT HALL EFFECT SENSORS

An inexpensive and accurate device for sensing rotor position and detecting rotational speed over a broad range of speeds in an electric motor includes a sense ring magnet (200) and two analog Hall effect sensors (108, 109, 722). The sense ring (200) is magnetized in an alternating north-south fashi...

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Bibliographic Details
Main Author LUTZ, JON F
Format Patent
LanguageEnglish
French
Published 27.01.2000
Edition6
Subjects
ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS
MEASURING
MEASURING ANGLES
MEASURING AREAS
MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS
MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE
MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
PHYSICS
TARIFF METERING APPARATUS
TESTING
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Summary:An inexpensive and accurate device for sensing rotor position and detecting rotational speed over a broad range of speeds in an electric motor includes a sense ring magnet (200) and two analog Hall effect sensors (108, 109, 722). The sense ring (200) is magnetized in an alternating north-south fashion wit h a number of poles that correspond to a number of motor field poles. The Hall effect sensors (722) are placed so that they measure magnetic flux tangentia l to the sense ring. The Hall effect sensors (722) are preferably located at a distance from the sense ring where the Hall effect sensor output waveforms a re substantially triangular, with a highly linear portion centered at zero flux between the minimum and maximum waveform peaks. The linear portions of the waveforms are decoded using an A/D converter and control software to provide an accurate measure of the rotor (724) position.
Bibliography:Application Number: CA19992337920