Performance prediction and analysis of disk-type eddy-current drivers

For the disk-type eddy-current drivers, an accurate and simple performance prediction method is developed. The static field produced by the permanent magnets and induction field by eddy currents are calculated using magnetic equivalent circuit method, and Faraday's and Ampere's law, respectively. In this model, many factors, such as the saturation effect of ferromagnetic materials, working temperature and the electromagnetic effects of back iron are taken into consideration. Compared with other methods, the model has a good agreement with three-dimensional finite-element method, and the average error is 4.9%. Finally, a prototype and corresponding test platform are made. Test results show that the proposed method is effective, and the maximum error is less than 8%. Besides, it is confirmed that eddy-current drivers can tolerate shaft misalignment and be used as speeders.