Two layer winding arrangement for an ironless, high speed axial-flux PM-machine

Ironless axial-flux machines present an attractive machine design avoiding core losses. The design challenge with these machines is to find a suitable winding arrangement that does not generate additional losses in return. This paper presents a new two layer winding arrangement for ironless winding carriers that doubles the effective number of slots. Shifting the winding layers by half a slot pitch reduces the harmonic content of the magnetomotive force. In combination with a stacked winding carrier, the slots close, improving mechanical safety and thermal conduction capabilities. This paper discusses the calculation model for this winding arrangement as well as pros and cons of the design.