Adaptive Observer of Resistance in Sensorless Estimation of Speed and Position in Brushless DC Electric Motor

Estimating the speed and position using measurable electrical parameters would allow establishment of sensorless control systems for brushless DC motors, without the need to use expensive sensors for the rotor position and speed. When the motor is running, it heats up and the stator resistance rises. This heat-dependent change needs to be reflected in the observer, as it would produce an error in rated speed and position. An adaptive algorithm can compensate for the change of resistance as a disturbing effect of the motor heating. The adaptive algorithm for estimating the resistance is synthesized using the function of Lyapunov. This article is useful for estimation of brushless electric motor speed and position with observer. It contains simulations with an adaptive observer of resistance for sensorless estimation of speed and position in brushless DC motor through measurement of voltage and current.