Systems and Methods for a Resolver and Motor Control with Enhanced Speed and Direction Monitoring

An electric motor comprising:

• a resolver comprising:
• (i) a resolver stator having a primary coil, a sine coil, and a cosine coil, and (ii) a resolver rotor mounted to, and configured to rotate with, an output shaft of the electric motor, wherein the resolver rotor comprises a secondary coil;
• a resolver-to-digital converter configured to (i) provide an excitation signal to the primary coil of the resolver stator, wherein the excitation signal excites the secondary coil of the resolver rotor, thereby generating a sine feedback signal in the sine coil and a cosine feedback signal in the cosine coil, (ii) receive the sine feedback signal and the cosine feedback signal, and (iii) determine a direction and a speed of rotation of the output shaft using the sine feedback signal and the cosine feedback signal;
• and
• a motor controller comprising one or more processors, and a non-transitory computer-readable medium storing thereon instructions that, when executed by the one or more processors, cause the motor controller to perform operations comprising:
• receiving the sine feedback signal and the cosine feedback signal,
• generating a rectified sine signal and a rectified cosine signal by way of sampling the sine feedback signal and the cosine feedback signal at a frequency less than a respective frequency of the excitation signal,
• determining a respective direction of rotation of the output shaft using the sine feedback signal, the cosine feedback signal, the rectified sine signal, and the rectified cosine signal,
• converting the rectified sine signal and the rectified cosine signal into a signed sine signal and a signed cosine signal, respectively, using information associated with determining the respective direction of rotation,
• determining a respective speed of rotation of the output shaft using the signed sine signal and the signed cosine signal,
• comparing the respective direction and the respective speed determined by the motor controller to the direction and the speed of rotation determined by the resolver-to-digital converter, and
• operating the electric motor based on the comparing.