Design and Evaluation of a PLL-Based Position Controller for Sensorless Vector Control of Permanent-Magnet Synchronous Machines

This paper presents a rotor position controller for sensorless vector control of permanent magnet synchronous machines (PMSM) based on a synchronous d-q frame phase-locked loop (PLL). Extending the capabilities of PLL´s for grid-connected converters¿using feedback linearization to ensure a constant dynamic response regardless of the operating region and rotor speed, the proposed controller takes advantage of the sinusoidal and balanced PMSM back-EMF voltages synchronizing the estimated and actual d-q frames. The resultant controller structure is readily linearized providing an accurate design tool based on frequency response specifications. A complete design procedure is provided, together with simulation and experimental results with a 3.5 kW PMSM drive, all of which verify the excellent results attained by the proposed PLL-based position controller.