Stable Equilibrium Rotor Positions for a Three-Phase Switched Reluctance Machine


Georg Tobias Götz, Philipp Tillmann, Anne Von Hoegen, Rik W. De Doncker, 2022 International Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia), 15-19 May 2022.



In mobile applications, weight and installation space are the major limiting factors that affect the system efficiency and consequently the cruising range. Reusing the machine windings of an electric machine as inductors e.g. in dc-dc converters of onboard chargers allows saving weight and space. However, currents in the machine windings due to the operation as a dc-dc converter can result in undesired torque produced by the machine. Therefore, stable rotor positions have to be found to prevent the machine from rotating in dc-dc operation. Rotor positions that are stable for a wide range of current distributions are determined, allowing flexibility in the choice of currents. In this paper, a method to analyze stable equilibrium positions for switched reluctance motors is presented. This method is used to determine the stable positions that allow flexible current distribution between phases. Additionally, locus curves, which are calculated, simulated and measured, illustrate and help to eval-uate the stable positions for these various current distributions.