Subdomain Analysis and Finite Element Design of No-load Magnetic Flux Density and Back-EMF in Radial Flux Air-cored Permanent Magnet Electrical Machine with Meddle Stator

In this Article, no-load magnetic flux density and Back-EMF of the redial flux Air-Cored permanent magnet electrical machine (RFAMP) is provided with meddle stator using the subdomain analysis. First, Analytical relationships of no-load magnetic flux density and Back-EMF of this machine are presented with maxwell equations and, then, these relationships are validated by finite element numerical results in Maxwell 16.02 software. This comparison shows that the difference between analytical relations and finite element results is 3% about. In this article, to calculate the Back-EMF resulting from the permanent magnet, all the components of winding conductor density distribution are used. It should be noted that in the investigations relating to this case, only the first radial component of the magnetic flux density is used. It is also shown that magnet width coefficient plays an essential role in the non- sinusoidal of the no-load magnetic flux density in the stator nominal radius and reduction of the number of pairs of poles in the magnetic saturation of yokes and induced voltage reduction. It is also shown that increasing the length of the air gap can have the greatest role in zero harmonic distortion of Back-EMF.