Dottorato in INGEGNERIA ELETTRICA, DEI MATERIALI E DELLE
NANOTECNOLOGIE

Titolo della tesi: Control Strategies for Handling Nonlinearities in High-Performance Synchronous Machine Drives

In the field of electric drives, many solutions have been proposed for the control algorithm according to the power electronic devices and machine types in order to make the most of the available hardware. However, not all control structures are able to ensure high system performance, and there is not a unique type of controller that works perfectly for all existing setups and applications. This thesis aims to deepen the study of the control algorithms for permanent magnet synchronous electrical machines, focusing on the system's nonlinearities. In the beginning, the design and implementation of the current regulator are treated. Subsequently, the analysis and compensation for the nonlinearities introduced by the inverter are performed. These are general aspects that are valid for all systems, independently of the machine type and the applications. Afterwards, two case studies are analyzed: in the first case, a permanent magnet synchronous reluctance machine is controlled in deep magnetic saturation; in the second case, a split rotor permanent magnet synchronous machine is controlled to achieve high speed in flux weakening operation. For both these cases, the mathematical model of the machine under analysis is derived, and a controller able to manage the machines' nonlinearity is proposed. Simulations and experiments are carried out to validate the theoretical analysis.