Transverse Flux Machine—A Review

For applications with high torque demand, gearboxes are commonly used to convert torque and speed in order to receive higher specific values for torque and power. This causes additional losses, cost, inaccuracies, effort, and noise. Eliminating the need of a mechanical gear and the associated disadvantages, Transverse Flux Machines with their high torque density are a very promising alternative. Despite a high torque density and a high efficiency, these types of machines are not commonly used. Due to the complex structure, challenges with mechanical design, and modeling of the machine behavior arise. Additionally, there are high requirements for the inverter due to the low power factor. This paper provides an overview of the state of the art including the potentials and advantages but also the problems and hindrances of these types of machines. Relating to linear and rotary machines from research and industry, the machine is introduced with its history, application and classification. Further, the general technical aspects, the influence of materials for flux guidance, the methods of modeling, methods for a minimization of torque ripples, as well as methods for power factor improvement are presented.