A PMSM speed sensorless control method based on improved sliding mode observer

Abstract

The present invention relates to a PMSM speed sensorless control method based on an improved sliding mode observer, comprising the following steps: Step 1: Establish a mathematical model of a three-phase permanent magnet synchronous motor, design a traditional sliding mode observer according to the mathematical model, and estimate the stator current and back electromotive force based on the traditional sliding mode observer; Step 2: Establish an improved sliding mode observer based on a saturation function, and improve the reaching law of the traditional sliding mode observer; Step 3: Use a low-pass filter and a Kalman filter to perform secondary filtering on the results observed by the improved sliding mode observer to obtain rotor angle information. The present invention solves the switching jitter problem of the traditional sliding mode observer through a smoothly switched saturation function; and solves the output noise problem of the traditional sliding mode observer through secondary filtering composed of a low-pass filter and a Kalman filter. The estimation accuracy obtained by the control method proposed by the present invention is higher and the robustness is better.