The More-Electric Aircraft Integrated Power Unit (MEA-IPU) represents a major dual-use product break-through, with numerous applications in both commercial and military marketplaces. The MEA-IPU eliminates all gearing and the entire oil lubrication system from today's power units, thereby doubling the reliability, cutting maintenance in half, and greatly reducing the support and logistic costs.
Integration of the electrical starting/generating components into the single-shaft IPU presented a significant challenge, adding many new interrelationships to the already complex tradeoffs involved, compared with the design of today's power units. In addition to iterations between efficient aerodynamic and robust mechanical designs, to achieve optimum IPU performance, the design engineers had to consider electromagnetic designs of the advanced Switched Reluctance Machine (SRM), Power and Control Electronics (P/CE), and Magnetic Bearings (MB) and controls as critical elements of the system design. This paper presents the technical tradeoffs and interrelationships observed in the process used for the MEA-IPU preliminary design, and the quantum Reliability/Maintainability/Supportability (R/M/S) improvements achieved. In addition, this paper will show why the optimum location for the high-speed, high-temperature SRM is internal to the gas turbine between the compressor and turbine.