Laboratory implementation of sensorless vector control of PMSM motor, using sliding mode observer and phase-locked loop

In this paper, a rotor position estimation algorithm based on sliding mode observer (SMO) and phase-locked loop (PLL) for permanent magnet synchronous motor (PMSM) control in STM32L431RCT6 microcontroller is presented. The proposed SMO and PLL-based observer has two advantages compared to the conventional SMO observer: reducing the undesirable phenomenon of chattering and improving the accuracy of rotor position estimation. In this research, a hybrid sensorless control system for PMSM drive has been designed, using the I-f startup method and a smooth transition to sensorless closed-loop vector control with SMO and PLL. C programming language is used to implement field vector control, phase-locked loop, sliding mode observer, proportional-integral controllers, space vector pulse width modulation, and coordinate transformations. The proposed method is implemented using STM32 family 32-bit microcontrollers. In the following, the presented laboratory results show the desirable performance of the proposed observer.