Frequency-Adaptive Flux Observer for Harmonic Suppression in Sensorless Control of PMSM

Due to nonideal factors such as initial integrator conditions, parameter mismatches, converter non-linearities, and measurement errors, rotor flux estimation using conventional rotor flux observer is prone to DC offsets and harmonic distortion. This paper proposes a frequency-adaptive observer based on active rotor flux observer. Experimental results demonstrate that the method significantly reduces harmonics and speed ripple, achieving superior control accuracy compared to existing methods.