Evaluation of Electrical Alternatives for Variable-Speed Gensets

Several benefits result from variable-speed capability in mobile engine generators with high frequency alternators ("HFAs") and power frequency converters ("PFCs"). The two primary benefits are increased power through higher engine speeds and increased efficiency through use of the optimal speed in tracking loads. The variable-speed units now available indicate that substantial improvements are possible, but they also raise questions about which HFA and PFC alternatives are the best. EPC will identify all practical alternatives and characterize them in a two-dimensional evaluation matrix that lists important characteristics versus alternative. The matrix will be prepared for power ranges of 5 to 30 kw, 30 to 100 kw and 100 to 1000 kw. In filling out the matrices, EPC will draw on its extensive experience with advanced power converters, variable-generation systems and its relationships with other companies with pertinent expertise. The matrices will lead to favored HFA and PFC alternatives. Although the result cannot be predicted now, a likely outcome is a HFA in the form of a permanent magnet generator and a PFC in the form of a resonant converter using MCTs. In an optional portion of the project, EPC will develop a workplan for Phase II in which prototypes will be assembled and tested.