High Density, High Efficiency Electrical Power Generation

State-of-the-art electrical starter/generator (ES/G) systems have become increasingly complex in design and integration due to significant power-demand increase in more electric aircraft initiatives such as the Joint Strike Fighter (JSF). They must provide high performance and high efficiency with limited active cooling availability. In order to satisfy the power demands and harsher environments anticipated in military and civilian aircraft platforms, new technologies must be investigated that allow significant platform-level performance improvements, including increased power density, increased efficiency, and utilization of cooling media with higher inlet temperatures. To address these challenges, PC Krause and Associates (PCKA) is developing a new generator technology that reduces temperature limitations associated with traditional synchronous generator designs. This new technology, called the ac-field electrical synchronous generator (ACESG), can operate at significantly elevated temperatures without sacrificing output power capability. Such a high operating temperature has several advantages: 1) temperature capabilities of cooling media, such as fuel and oil, can be better utilized, 2) heat can be radiated and convected into the environment, and 3) direct integration of the ACESG at the turbine engine becomes possible. All these advantages will result in significant reduction of active cooling, thus reducing size and increasing power density of the overall ES/G system. In the Phase I effort, PCKA has demonstrated the feasibility of the ACESG's electromagnetic and thermal concepts with modeling and simulation. It was shown that the elevated cooling media temperatures could yield a significant size and performance reduction in cooling loop components such as pumps and heat exchangers while improving overall aircraft performance. In the Phase II effort, PCKA will demonstrate the ACESG technology in a hardware prototype (TRL 4) and evaluate the technology impact on the JSF aircraft in a comprehensive cost / benefit study. If successful, PCKA will transition the ACESG technology to DoD programs under Phase III contracts and/or commercial applications.