An asymmetrical six phase induction machine for flywheel energy storage drive systems

Energy storage systems have become an essential part of power utilities due to their capability of providing high level of power quality and stability. Flywheel energy storage systems (FESSs) are now employed with numerous grid and renewable energy applications due to their operational merits. Some of these applications are related to fault ride-through and critical load support. Therefore, the reliability of the FESS should be ensured. The main concern of the FESS drive system reliability is the applied machine type and the required power converter. In this paper, an asymmetrical six phase machine is proposed to drive a low-speed FESS in order to enhance the overall reliability and improve system fault tolerance capability. Different simulation case studies during healthy and faulty conditions are presented using MATLAB/Simulink. The proposed FESS is built experimentally to investigate system performance during both cases.