Feedback Matrix Design of Adaptive Full-Order Observer for Stator Resistance Robustness Improvement in Speed Sensorless Induction Motor Drives

In the speed sensorless drive of induction motors, the adaptive full-order observer has been verified effective for its stability and accuracy. However, it is essentially a method based on the motor model, meaning that the accuracy of motor parameters has a significant impact on the system performance. Especially in the low-speed region, since the voltage drop across the stator resistance directly impacts the observer input, it plays a decisive role compared with other resistance and inductance. Given that the stator resistance is highly susceptible to variations in temperature, it limits the practical applicability of observer. To address the problem, a meticulous design of observer feedback matrix is presented for stator resistance robustness improvement. The studied method adopts an intuitive graphical analysis for the adaptive full-order observer, avoiding complex formula derivation. The universal issue for different induction motors is considered by designing the parameters of the feedback matrix meticulously. The experimental results on a 2.2 kW induction motor platform validate the effectiveness of the studied method.