Permanent magnet motor with sinusoidal back-EMF waveform and related motor controller for position sensorless drives

A system comprising:

• an inverter configured to generate a current;
• a permanent magnet motor coupled with the inverter, the permanent magnet motor configured to generate a back-electromagnetic force (EMF) waveform that is substantially sinusoidal in response to receiving the current from the inverter;
• and
• a motor controller including:
• a sliding-mode observer circuitry having:
• a combiner coupled with the permanent magnet motor, and configured to determine a current error based on an estimated current and the current received by the permanent magnet motor;
• and
• a sliding-mode controller coupled with the combiner, and configured to estimate the back-EMF waveform based on the current error;
• and
• a position observer circuitry configured to estimate a characteristic of the permanent magnet motor using the estimated back-EMF waveform, and the position observer circuitry including:
• a first integrator coupled with the sliding-mode observer, and configured to generate an integral output based on an integral controller gain and a continuous EMF vector;
• and
• a second integrator coupled with the first integrator, and configured to generate an estimated position by integrating the integral output.