This award will support cooperative research in electrical engineering between Dr. Alan Wallace, Oregon State University, and Professor Stephen Williamson, Cambridge University, England. The objective of the proposed project is to investigate advanced modelling techniques for brushless doubly-fed electrical machines (BDFM's), a new development in adjustable-speed drive and variable-speed generation systems. At Oregon State University, two proof-of-concept machines have already been built and linear mathematical models have been developed, which give performance predictions which correlate with test results at specific conditions. However, the BDFM is intended for operation over a wide range of speed, frequency, and magnetic loading. Under such conditions, saturation and hysteresis in magnetic materials, and skin-effects in large sectional conductors make linear models inadequate for design purposes. The most advanced techniques to handle nonlinear analysis and design of conventional-cage rotors have been developed by Professor Williamson of Cambridge University. These techniques, which periodically utilize finite element analyses of internal machine fields to determine revised values of linear model parameters, appear to offer the best chance of modification to cover the unique BDFM rotor configurations. The US principal investigator proposes to adapt the Cambridge techniques for inclusion in Oregon State University's models of BDFM in order to develop detailed design for specific applications currently being selected at OSU. The results of this research will make an important contribution to the potential commercial viability of BDFM's.
