Comparison of low-cost wound-field switched-flux machines

This paper proposes a three phase wound-field switched-flux (WFSF) machine. It is found that under the constraint of same copper loss, this machine has much higher average torque compared with the conventional 12-slot/8-pole machine with segmented rotor and 12-slot/5-pole WFSF machine. All of those machines have been optimized to achieve the maximum torque for comparison. The performance, including back-EMF, cogging torque, and static torque, of four machines are analysed and compared by two-dimensional (2-D) finite element analysis (FEA) and validated by experiments on the prototype machines.