Magnet coil power supply by a self-excited induction generator with a flywheel for a small tokamak, PHiX

•Non-superconducting tokamaks require energy storage system when the power grids are not robust.•Focused on flywheel energy storage employing an induction motor using self-excitation phenomena.•It has advantages that robustness, simpleness and no need to use large inverters for motor control.•Achieved 117 kW of peak power and 0.25 s of flattop period using a 55-kW induction motor.