Adaptive sensorless position estimation of a field-weakened permanent magnet machine over an extended temperature range

A sensorless position estimation scheme based on a modified model reference adaptive structure, and designed specifically for a permanent magnet machine deployed on-board an aircraft and subject to extreme temperatures, is developed and verified experimentally. The technique, based on two flux models, is robust to temperature variation and operates in both the constant torque and the constant power regions. A simulation model is developed to include the effect of temperature on stator resistance and the back-emf constant. Experimental results confirm the accuracy of the model over the temperature range −40°C to 100°C. Estimated position is accurate to within 2°mech enabling the machine to operate with less than a 1% reduction in rated torque.