Size and Weight Reduction of an In-Wheel Axial-Gap Motor Using Ferrite Permanent Magnets for Electric Commuter Cars

Abstract

In-wheel type permanent-magnet synchronous motors for electric commuter cars are required to be compact and light to use limited wheel space effectively and reduce unspringing weight. Therefore, our previous papers presented a low-cost in-wheel axial-gap motor that uses ferrite permanent magnets. This motor adopted an open slot structure to reduce production costs. However, to achieve further size and weight reduction, we examine here in detail the adoption of a semiclosed slot structure instead of an open slot structure. Experimental results show that the semiclosed slot structure is effective in realizing size and weight reduction.