Recent Advances on Wound Field Flux Switching Machines: A Review

Switched flux machines (SFM) provide a robust rotor structure and effective thermal management because their excitation windings are entirely located on the stator. These machines are capable of producing high torque density. Permanent magnet (PM) designs offer high electromagnetic performance. However, the increasing cost of rare earth magnets, their temperature sensitivity, and the risk of irreversible demagnetization constitute significant limitations. For this reason, wound field switched flux machines (WFFSM) have emerged as an alternative solution. These structures do not contain permanent magnets, and the field current is controllable, enabling flexible operation over a wide speed range. In this review study, wound field switched flux machines are examined systematically. Applications in renewable energy systems, electric and hybrid vehicle drives, as well as industrial and marine systems are evaluated. In addition, performance enhancement methods, efficiency improvement approaches, cost oriented design strategies, modeling techniques, and control methods are analyzed. The study synthesizes the existing literature comprehensively and provides a guiding framework for future research. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.