Ricerc@Sapienza

The paper deals with a sliding mode based sensorless control for permanent magnet synchronous motors (PMSMs), where an observer using only electrical signals, guarantees the robust asymptotical speed tracking without measuring rotor velocity and position. To compute online the motor parameters and the initial rotor angular position, a set of polynomial equations has been derived from the electrical subsystem. Performances are validated by realistic simulation results.

Extended Electro Motive Force observers exhibit good performances at medium and high speeds. However, voltage and current errors, together with parameter uncertainties, lead to inaccurate rotor position estimation. Thus, this paper proposes a novel analytical approach to identify estimated position errors of Extended Electro Motive Force Observers in both the stationary and the estimated synchronous reference frames. A unified analytical framework is presented, that allows to derive a closed-form expression for these errors in both frames.

Extended Electro Motive Force Observers in the estimated synchronous reference frame allow to estimate rotor position at medium and high speeds for Interior Permanent Magnet Synchronous Machines. This paper focuses on the analysis of the dynamic performances of these observers. Use of complex vector modeling allows to demonstrate that these performances are speed dependent. In order to overcome this problem, a Complex Vector Observer is proposed. It is proven that this structure achieves good robustness against load torque and speed variations over different operating conditions.