Optimized Finite Element Mapping of Multiphase Bearingless Motors

The current state of the art suggests the adoption of three-phase electrical drives in most industrial and automotive applications. However, studies report that by introducing even more motor phases, it is possible to obtain higher efficiency, increased power density, and enhanced controllability. In this context, multiphase bearingless electric machines represent an innovative solution in the field of electric drives, combining torque production and active control of radial forces for rotor magnetic suspension. These features allow multiphase electric drives to be employed in several industrial applications requiring precise control, high efficiency, and reliability. Consequently, an accurate design validation process is essential to ensure consistent and satisfactory performance. Before prototyping, this validation typically relies on electromagnetic simulations performed with finite-element software, often involving thousands of computationally intensive runs. This work aims at increasing the efficiency of the design stage by reducing the computational effort required for the full finite-element simulation of a bearingless permanent magnet machine, thereby enabling the generation of look-up tables for control simulations with minimal resource usage. After an introductory overview of multiphase and bearingless machines, a detailed analysis of the electromagnetic mapping of multi-sector surface-mounted permanent magnet motors is developed, considering also the effects of eccentricity on the machine under analysis. Strategies for the reduction of computational load are then proposed and evaluated, achieving a significant reduction in terms of simulation time and number. However, further studies and experimental validation remain necessary to fully assess the accuracy and reliability of the proposed approach in real-world applications.