A Comparative Analysis of Rolling-Rotor Electrical Machines of Different Winding Designs

Low-speed electrical machines with high specific torque are in demand in many areas of technology where weight and size parameters are important. Traditionally, permanent-magnet machines are used in them, which, however, are characterized by high cost and a small range of speed control. In this regard, research to increase the specific torque of electrical machines with the reactive nature of the electromagnetic torque is urgent. One way to achieve high specific characteristics of such machines is to use a special topology of the magnetic system closely integrated with mechanical-transmission rolling-rotor electrical machines. To operate effectively, such machines must develop a large radial force of attraction, which is why they use special types of windings. There are several known versions of winding designs, but there are no data comparing them with each other. For purposes of a correct comparison, the article performs multidimensional parametric optimization of four variants of magnetic systems with different winding designs according to the torque maximization criterion. As a result, the specific moment is calculated for each magnetic-system version. The obtained results make it possible to draw conclusions about the effectiveness of each winding circuit. These results can be used in the design of rolling-rotor electrical machines.