Magnet shaping for minimal magnet volume in machines

Summary form only given. Electrical machines may use permanent magnets (PM) to create an excitation field and obtain a no-load voltage. It is common practice to use rectangular blocks of PM, and place them side-by-side with alternate polarities. It is unclear whether the use of rectangular blocks is the most cost-effective PM shape. Rare-earth PMs are expensive. The amount of PM material should be minimized whenever possible. This paper presents a method to derive PM shapes with a high amount of flux created in the stator winding per volume of PM material.