ANALYSIS OF VOLTAGE MODEL-BASED ROTOR FLUX ESTIMATION FOR CLOSED-LOOP CONTROL METHODS WITHOUT SPEED ENCODER

Tóm tắt

Induction motors (IMs) are key components in numerous industrial drive systems due to their simple structure, low cost, and high reliability. However, achieving accurate and robust speed control under varying load conditions remains a significant challenge, particularly for sensorless drive systems. This paper investigates the effectiveness of the Model Reference Adaptive System (MRAS). The speed estimation technique is applied to two commonly used IM control strategies: scalar control using the voltage model (SC-VM) and field-oriented control using the voltage model (FOC-VM). In both approaches, the rotor speed and flux angle are directly estimated from measured stator voltage and current signals, thereby eliminating the need for mechanical speed sensors. Simulation results obtained under various operating conditions demonstrate that the MRAS-based sensorless control strategy provides high estimation accuracy, good dynamic response, and stable system performance, while reducing system cost and simplifying the drive structure. A comparative analysis further indicates that scalar control is well-suited for applications with low cost and simple structural requirements, whereas field-oriented control better meets demands for high dynamic performance and high control accuracy. These findings offer valuable insights for selecting appropriate control strategies in practical induction motor drive applications.