Motori ad eccitazione ibrida: analisi, progettazione e controllo

This dissertation includes many research activities in the field of analysis, design and control of Electrically Excited Synchronous Motors (EESM) and Hybrid Excited Permanent Magnet Motors (HEPM) drives. EESM and HEPM motors are promising machine configurations for variable speed applications thanks to their high torque and power density, high capabilities in a wide speed range and low amount of permanent magnets. Different architectures of these motors are analysed and different tests under various operating conditions are carried out and described in the thesis. Structural and thermal limits are also taken into account. In Part I, some basic background theory of electrical machines is reported, focusing on EESM and HEPM motors. Their general architectures is examined, including series and parallel configurations. The performance under no-load and load conditions are analyzed and different comparative studies between PMs motors, EESM and HEPM motors with the same size are presented. Finally, structural and thermal issues affecting rotor winding machines are discussed. Part II moves the focus on theoretical and effective design. Analytical techniques are used to calculate the machine parameters, for given requirements of maximum torque at low speed and flux weakening operating speed range. EESM and HEPM motors are detailed designed and optimised to achieve the required performance. This part concludes in illustrating the procedure to select an optimum motor geometry, followed by the prototype construction and the description of a series of experimental tests. Finally, Part III examines the electrical control strategies employed for HEPM motors, covering control techniques such as maximum torque per Amps control, sensorless control and flux weakening operation control. It also considers an extension of implicit Model Predictive Control to include voltage and current constraints. This dissertation reports analytical, finite element and experimental validation, providing valuable insights into the design and control of EESM and HEPM motors, highlighting their advantages and disadvantages.