Lu Jiang

Sensorless Control of PMSMs with a Passivity Based Observer Subject: Dissertation Proposal Presentation and Comprehensive Examination

Date: Thu, 25 Apr 2002

Abstract: Permanent Magnet Synchronous Motors (PMSMs) have wide applications in industry, especially in servo drives such as machine tools and industrial robots. Control of PMSMs without shaft sensors is desired from cost and reliability considerations. Based on the passivity dissipation theory, a full state observer was developed in this proposal. With this observer, the rotor position and speed were estimated from the reference stator voltages and the stator currents feedback. Including both electrical variables (currents) and the mechanical variables (rotor position, speed and torque) in the observer removed the steady state assumption and guaranteed the stability. Design parameters allow adjustments in error convergence rates. The observer was designed from the motor equations on the estimated rotor frame. With a base change, the differential equations of the estimation errors were converted into a form where the stability is more obvious and the error convergence can be adjusted with selection of observer parameters. The proposed observer was implemented on a surface mounted magnet PMSM together with a passivity based controller. The experiment results proved the validity and accuracy of the observer design. For its application on interior magnet PMSMs and in the higher motor speed condition, some modifications were made both on the observer design and on the experiment setup implementation. Experiment results demonstrated the validity of both the principle analysis and the practical improvements.

Advisors: Professor Aleksandar Stankovic Professor Gilead Tadmor

Committee Members: Professor Aleksandar Stankovic Professor Gilead Tadmor Professor Bahram Shafai