A Novel Current Limitation Technique Exploiting the Maximum Capability of Power Electronic Inverter and Bearingless Machine

This article presents a current limitation technique for a multiphase bearingless machine featuring a combined winding system. This winding structure allows the machine to produce both suspension force and motoring torque. The main challenges with the combined winding configuration consist of decoupling the suspension force and torque generation and designing a proper current limitation algorithm. The former topic has been already tackled and presented in previous publications, while the latter will be addressed in this article. In particular, the proposed suspension force control technique will allow to prioritize either suspension force or torque generation. In this article, the priority is given to the rotor levitation, hence the suspension force rather than the torque is essential. Finally, simulation results and experiment validation on a 1.5kW/3000 r/min prototype machine are provided.