Study of Sensing-Free PMSM Control System Based on Improved Sliding Mode Observer
Traditional sliding mode observers have significant estimation errors in speed and angle. These errors mainly come from high-frequency chattering caused by the sign function,inverter harmonics,impre-cise phase compensation of low-pass filters,and the interference of noise on arctangent operation. Regarding these error sources,by studying and improving the switching function,sliding mode observer structure,fil-ter,angle and speed estimation,errors can be reduced. A new type of sine piecewise composite function in-stead of the traditional sign function is adopted in this improved sliding mode observer to reduce the chatte-ring;High-order sliding mode and complex coefficient filters are used to filter out higher-order harmonics and to further suppress chattering;Normalized phase-locked loop is used to extract rotor position and speed information to improve the observation accuracy of angle and speed. Experiments show that this improved sliding mode observer can reduce speed error with 50％ and angle error with 66％.
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维普
