An Appreciation of using Halbach Magnets Array in Axial Flux Permanent Magnet Machines

Abstract

Using Halbach magnets array in an axial flux machine offers many benefits, including the needlessness of back iron in the rotor, making it practically ironless. Being ironless, the electric machine becomes highly efficient since there are no core losses. Apart from that, the Halbach magnets array essentially reduces the machine’s axial length. Halbach magnets array uses a unity magnet width to pole pitch ratio $(\lambda p)$. In contrast, conventional magnets need an optimized fractional value of magnet width to pole pitch ratio to get higher magnetic flux density. In this study, the strength of the magnetic field density for the Halbach magnets array is examined and compared with that of the conventional magnets array. A fair comparison between the Halbach array and conventional array is only conceivable concerning their magnet volume for an optimized magnet width to pole pitch ratio. A lower machine thickness is always preferable for axial flux machines, where the Halbach array can meet this condition. All the experiments have been conducted in a simulation environment developed in ANSYS Maxwell software.