Size and weight reduction of an in-wheel axial-gap motor using ferrite permanent magnets for electric city commuters

In-wheel type permanent magnet synchronous motors (PMSMs) for electric city commuters are required to be compact and light in weight in order to utilize limited wheel space effectively and reduce unspringing weight. Therefore our previous papers presented a low cost in-wheel axial gap motor using ferrite permanent magnets. This motor adopted open slot structure to reduce production cost. However, owing to achieving further size and weight reduction, we newly examine to adopt semi-closed slot structure instead of open slot structure. This paper introduces its examination results in detail. Moreover, experimental results show that the semi-closed slot structure is effective in realizing size and weight reduction.