A fast adaptive sliding mode observer for permanent magnet synchronous motors based on new segmented reaching law

To improve the performance and anti-interference capability of permanent magnet synchronous motor (PMSM), a fast adaptive sliding mode observer (SMO) for PMSM based on a new segmented reaching law (NSRL) is proposed. First, a new type of segmented reaching law (NSRL) is constructed, which combines exponential functions and power functions, and defines the switching function based on tangent-saturation and hyperbolic tangent functions. Next, the chattering boundary width of the NSRL is analyzed. The analysis shows that the proposed NSRL effectively reduces chattering and accelerates the adaptive convergence speed through segmented combination and parameter adjustment. Furthermore, to enhance the observation accuracy of the rotor position, a new segmented sliding mode observer (NSSMO) based on a phase-locked loop (PLL) is introduced. Stability analysis and proof of this observer are conducted using Lyapunov theory. Simulations and experiments demonstrate that the NSSMO exhibits fast adaptive convergence, reduced chattering range, high overshoot constraint, excellent speed and position tracking accuracy, and strong anti-interference performance.