Position Sensor with optimized accuracy

Improving position signal accuracy

illustration: Position Sensor with optimized accuracy  

For applications requiring high accuracy in position signal like sinusoidal control of synchronous electric motors, MMT has improved its basic concept of through shaft rotary position sensor in order to achieve a better accuracy of the sensor output signal. This improved accuracy is achieved thanks to an improved magnetization process (possible use of multipolar sinusoidal magnetization) and the use of two sensitive ICs placed at 90 electric degrees, both of them measuring two components of the magnetic field (one normal and one tangential component for each IC). Thanks to an electronic processing of these four components of the magnetic field, we are able to cancel some parasitics harmonics and so to optimize the position measurement accuracy. With the same electronic processing, we are also able to partially filter the effect of a magnetic stray field.

MMT proposes to its customer high accuracy position sensors with the following features:

  •  Accuracy ≤ ±1 electrical degree on the automotive temperature range -40°C to 150°C (equivalent to +/- 0.3% of the stroke in case of an absolute 360° measurement)
  •  Possible use of multipolar sinusoidal magnetization of the ring magnet for improved sensor accuracy
  •  Reinforced robustness against magnetic stray field
  •  Scalable design with through shafts from 3mm to 150mm
  •  Use of existing Hall ICs and compatibility with other measurement principle like magneto-resistance (MR)
  •  Good robustness against geometrical and application tolerances (rotor axial shift, sensing ICs position, rotation speed, ...)
  •  Patents pending and Licenses available

For more information, you can contact us there or download our presentation at Sensor + Test Nuremberg in 2011.

 

MMT also provides rotary sensors,sensors combining two position signals, sensors for 2D measurement and sensors using a variable reluctance.

 

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