Research on Sensorless Synchronous Reluctance Motor Control Based on SMO

Due to the sign function of the traditional sliding mode observer producing jumps at the zero crossing point, high-frequency oscillations occur, making it unable to converge smoothly. Meanwhile, the approach velocity of the adopted isokinetic approach law is a constant and cannot be adjusted dynamically. Therefore, this paper designs a new exponential function and exponential approaching law for improvement. By building simulation models of the traditional sliding mode observer and the improved sliding mode observer for verification, simulation comparisons show that oscillations are significantly reduced and tend to be smooth, with faster response during speed mutations.