| Abstract |
Any electric motor has intrinsic feed-backs, depending on the movement or on the load. These behaviors can be systematically used in order to create indirect sensors or observers, using PC-board or integrated electronics. The main possibilities are : dynamic position and speed sensors using a direct or indirect measurement of the back-EMF, the third harmonic of thf) back EMF or the current analysis; static position sensors using the PM saturation effect or the variable reluctance; torque sensors using the current and voltage measurements in order to determine the load behaviour. These techniques can be mainly applied to EC motors as the brushless DC motor or the switched reluctance motor. A comparative analysis of the main solutions is presented and summarized in a table, proposing the best choices according to specific applications. |
