Sensorless control of PM synchronous motors with a robust nonlinear observer

This paper is devoted to extensions and experimental investigations of a recently proposed robust, nonlinear and globally convergent position observer for surface-mounted or non-salient permanent magnet synchronous motors (SPMSMs). A key feature of the robust observer is that estimation of the rotor position θ requires only the knowledge of stator resistance R and inductance L. In this study, the performance of SPMSM sensorless (self-sensing) control is verified for the case when the estimated position signal is used to control the motor and with DC link voltage measurement only. The closed-loop control system combined with the nonlinear observer is also compared with the state-of-the-art industrial controller. It is demonstrated that the nonlinear observer achieves a significant improvement of the closed-loop performance in both low- and high-speed operation. At the same time, the availability of a complete theoretical analysis allows for portability of results to other platforms and drives. Proposed approach can be useful in fault detection and self-diagnosis of the cyber-physical systems with embedded PMSM.