A new flat winding construction for direct liquid cooled axial flux machine with segmented stators

Abstract

This paper proposes a new flat winding construction for use in a direct liquid cooled segmented stator. Following a demonstration of how the conductivity across the windings limits further increasing in current density, the paper proposes a new construction using flat windings to replace traditional concentrated windings. The paper addresses some of the more practical challenges with the manufacturing of this type of windings. A thermal model is developed and used to demonstrate that the new flat windings construction offers a reduction in maximum winding temperature by approximately 97°C, for a typical operating point of 300 Nm and 1500 rpm of the YASA machine. The lower operating temperature offers an improvement in the lifetime of the machine. Alternatively, for the same maximum temperature, the flat windings construction offers a 35% increase in current density.