Principles and Characteristics of an Ultralightweight Electromagnetic Resonance Coupling Machine With a Cage Rotor

To produce an ultralightweight machine for electric aircrafts, we propose a machine in which electrical energy is converted between the stator and the rotor via magnetic resonance coupling (MRC). This action causes electromagnetic resonance between the multiphase windings of the stator and the cage bars of the rotor. Electromagnetic resonance coupling technology allows electrical machines to convert energy without a magnetic core, thereby allowing the production of ultralightweight machines. In this study, we propose a machine with a cage rotor based on MRC, and we describe its operating principles and characteristics induced by MRC. A model of the proposed cage-type MRC motor is subjected to magnetic analysis to assess its rotational energy conversion in a rotating machine and to understand its essential characteristics. Our results confirm that the proposed cage-type MRC motor without a magnetic core can convert electromagnetic energy between the stator and the rotor and produce sufficient operating torque. This motor operates with a slip torque curve similar to that of an induction motor, and its torque increases with resonant frequency.