The sliding-mode observer for PMSM field-oriented sensorless control with adaptive filter and PLL

Abstract

More recently, permanent magnet synchronous motors (PMSM) have been widely applied to power source for different applications, such as high precision tracking systems, standalone electric and unmanned aerial vehicles, industrial robotics, marine propulsions, etc., due to their advantages to conventional competitors for example induction motor with squirrel-cage rotor. In order to reduce the cost of AC drive, the removal of the mechanical sensors is required. Hence, the sensorless motor control is more preferable and is based on electrical measurements, namely, three-phase currents and voltages. The paper is devoted to sensorless field-oriented control design procedure for a non-salient PMSM. The proposed control strategy is employed on full order sliding-mode observer which provides the output insensitivity to parameter changes and disturbances. In order to reduce th e high-frequency chattering and enhance the rotor position estimation quality and accuracy, the band-pass filter with tracking of the central frequency to the speed reference is applied. To obtain actual information about the unmeasurable rotor position and speed, the phase-locked loop with cascade connection of adaptive proportional-integral controller is employed. A simulation of the dynamic starting mode of a PMSM under zero initial conditions has been performed by MATLAB/Simulink environment. As can be concluded from the simulation results, proposed sensorless field-oriented control strategy provides quick response as well as low rotor position estimation error both transient and steady-state behavior. The research significance of proposed PMSM sensorless field-oriented control strategy is to provide the wide range of motor speed operation, strong robustness of estimated rotor position to parameter perturbations as well as quality suppression of high frequency chattering effect owing to the switching attribute and the internal control discontinuity of sliding mode, whereby the practical application of a sensorless variable-frequency synchronous electric drive is expanding.

Keywords

• permanent magnet synchronous motor
• sensorless field-oriented control
• observer of back electromotive force
• sliding mode
• adaptive band-pass filter