Torque and torque components in high-speed permanent-magnet synchronous machines with a shielding cylinder

A demand for more efficient electrical machines with a high power density is driving the interest for high-speed permanent-magnet synchronous machines (PMSMs). However, the design of such machines is a challenging task. One of the problems is that the effect of the shielding cylinder, a conductive sleeve around the magnets, on the machine's performance has not been studied extensively. To cope with that problem the authors of this work introduce an analytical method to study the torque in high-speed PMSMs. The presented method implies dividing the torque into two components, depending on how they are produced. The method is successfully validated and an illustration of its advantages is provided.