Stator Flux Observer for the Sensorless Speed Control of Synchronous Machines with Uncertain Torque Constant

In this paper, a recently designed adaptive stator flux observer (SFO), which provides estimates of rotor position and torque constant for surface mounted permanent magnet synchronous machines (PMSMs), is included in a speed sensorless control. Simulations and experimental results are carried out in order to evaluate the robustness of the whole control architecture with respect to uncertainties in the electrical parameters of the motor, as well as to the mismatch between the actual stator voltages imposed to the PMSM and the ones used for the observer, especially when low speeds are involved.

I. Introduction

Surface mounted permanent magnet (PM) synchronous machines (PMSMs) are widely used in different industrial applications due to their excellent serviceability and durability, high efficiency and power density, high torque to inertia ratio and absence of external rotor excitation and rotor windings ensuring better efficiency compared to induction motors [1].