Sensorless adaptive field oriented control of brushless motor

"Field Oriented Control" (FOC) is the the most efficient way to control a bruchless motor. This control generates constantly a magnetic field perpendicular to the rotor, which maximises its efficiency. However, to do so, it requires knowledge of the rotor position in real time. The latter can be measured using additional sensors which can be problematic for many reasons. Alternatively, the so-called "sensorless" control consists in the analysis of the electric motor response but needs to know certain characteristics of the engine, compromising compatibility. In this paper, we propose an adaptive control based on the hypothetical rotor position method, which overcomes these problems. This control has also the advantage of remaining optimal although the motor parameters vary over time due to external conditions (e.g. temperature) or aging. The results obtained are very promising and seem to prove its suitability for implementation in real applications.