A High Order Nonlinear Adaptive Observer for PMSM Speed-Flux Transformation Model: A PMSM Sensorless Control Scheme

This article presents a novel speed-flux transformation model, derived from the traditional active flux model of permanent magnet synchronous motor, which features a known regression term of speed. This advancement achieves nonlinear parameterization of motor speed, enabling the construction of a speed adaptive observer. Then, a high order nonlinear adaptive (HONA) observer is developed by adopting the proposed model, which employs a nonlinear parameter updating law and high order sliding mode correction terms for error estimators, thereby enhancing the system's dynamic response. Due to the known regression term nature of the proposed model, the adaptive observer ensures stability at near-zero speeds, leading to superior performance in low-speed and reversal scenarios. After rigorously proving the observer's stability, a detailed tuning guide for parameters is provided. The effectiveness of the HONA observer is validated through both numerical and experimental works.