Model Reference Adaptive System-Based Speed and Position Estimation for PMSM Drives

Accurate speed and rotor position estimation are crucial for high-performance sensorless control of Permanent Magnet Synchronous Motor (PMSM) drives. However, DC offsets in measured electrical signals can be caused by sensor inaccuracies, amplifier offsets, measurement errors, and external disturbances, which may introduce errors in the estimation quantities, leading to degraded control performance. This paper proposes an improved Model Reference Adaptive System (MRAS)-based DC offset elimination technique to enhance the accuracy of speed and rotor position estimation in PMSM drives. The proposed method employs a low-pass filtering strategy to extract DC offset components and an adaptive correction mechanism for real-time compensation. The proposed MRAS control strategy is validated through extensive simulations on a 1 kW PMSM drive system. Results show significant improvements in rotor speed and position estimation under low-speed (1000 rpm), high-speed (3000 rpm), and speed-transition conditions. The method effectively eliminates DC offset within 0.01s for position estimation and 0.06-0.8s for speed estimation for all speed conditions, ensuring smooth and accurate tracking. Furthermore, the MRAS approach mitigates transient errors during speed transitions, enhancing the robustness and stability of PMSM drives, making it a reliable solution for industrial applications.