Magnetically coupled electrical machines for renewable energy applications

Mechanical coupling between the drive and the driven systems in electrical machines poses design challenges. Rigid and flexible couplings have a trade-off between the rotational speed and vibrations, which are associated with misalignment. This paper discusses a procedure for obtaining the dimensions of a pre-designed rigid (flange-type) mechanical coupling system using the finite element-based electromagnetic full-wave simulator element software (FE, ANSYS) for a benchmark torque and proposes a process that replaces a mechanical coupling system by a magnetic coupling system. This paper also elaborates on the comparative performance analysis between magnetic coupling and mechanical coupling. The simulation results of this analysis affirm that adjusting the flange diameter and thickness tune the magnetic coupling system performance similar to that of the mechanical coupling with an added advantage of auto-decoupling when exposed to higher loads. The auto-decoupling property protects the mechanical and electrical system from damage. This research considers the use of COMSOL Multiphysics software for determining the optimum number of magnets to couple the flanges for specified torque and speed, the distance between the flanges, and limits of angular and parallel misalignments. JMAG software is used for the analysis of the dynamic behaviour of the magnetic coupling system and the holding torque characteristics. This manuscript shows that the magnetic coupling technique has promising results in the renewable energy industry, such as wind energy, wave energy and electric vehicles.