US Patent 11637482 Magnetic sensor system for motor control

The present disclosure provides a magnetic sensor system for monitoring the position of the rotor relative to the stator for use in electronic motor commutation. The system uses two magnetic sensors with a back bias magnet, the magnetic sensors being configured to detect changes in the magnetic field direction caused by the magnetic field interacting with two moveable targets that are being rotated by the motor shaft. The unique phase shift between the signals measured at each sensor can thus be used to determine the relative position between the stator and the rotor. In this respect, the system makes use of the Nonius or Vernier principle to measure rotational displacement, however, the scale of the encoder is defined by the number of motor pole pairs.