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In this paper, the reluctance torque is utilized for improving the starting and average torques of a conventional brushless wound field synchronous machine (BL-WFSM). The conventional BL-WFSMs have an inherent issue of zero-starting torque. The existing BL topologies use expensive rare-earth permanent magnets (RE-PMs) to improve the starting torque; however, the marker price of RE-PMs fluctuates. Therefore, this paper proposes the use of the reluctance torque for improving the starting and average torques of BL-WFSMs. The winding topology and machine layout are adopted, from recently published work. The suggested approach increases the reluctance effect in BL-WFSM by optimizing the rotor shape. The reluctance effect is optimized, to improve the starting and average torques. The Kriging method and a genetic algorithm are used for the rotor optimization. A two-dimensional finite element analysis confirms the improved starting and average torques based on the increase in the reluctance torque. [ABSTRACT FROM AUTHOR]

Different topologies for brushless wound rotor synchronous machines (BL-WRSMs) have been proposed recently. This paper proposes a new model for the existing sub-harmonically excited BL-WRSM to eliminate the unbalanced radial force presented in the initial model. The initial and proposed models are analyzed using a two-dimensional finite element method. Furthermore, a variable-speed analysis for the BL-WRSM is conducted by altering the stator input current. Finally, a prototype of the proposed model is built and tested at the rated speed, to compare its performance with that of the conventional WRSM. Simulation and experimental results validate the proposed BL-WRSM's operation. [ABSTRACT FROM AUTHOR]