Novel flywheel energy storage system

This paper investigates the performance of a novel powertrain architecture that utilises a magnetic continuously variable transmission (mCVT) as a power-splitting device for a flywheel energy storage system (FESS). In this configuration, the primary power exchange with the grid occurs through a grid-connected wound-field synchronous machine (WFSM), thereby contributing to the grid's physical rotational inertia. Conventional flywheels typically offer only virtual inertia, exchanging power with the grid through power-electronic converters. To manage FESS responses to grid-frequency variations, an mCVT torque control strategy is proposed. A detailed electromechanical model of the proposed FESS is developed, and simulation studies are undertaken to highlight its performance. Hardware-in-the-loop validation using a real-time target machine and a grid-connected WFSM confirms the fidelity of the proposed model and control framework, with close agreement observed between predicted and measured power dynamics.