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An electrical system composed of an integral main engine electrical starter/generator and a power management and distribution system for a high performance more electric airplane is presented. The paper emphasizes the fault tolerance and high reliability requirements and discusses the necessary architecture to satisfy them. A number of critical technical issues associated with the more electric airplane, such as severe EMI environment, regenerative power, and system integration and stability are discussed.

Most electronic systems, including electric motor drives and electric power conditioners, require the use of electromagnetic devices, such as inductors and transformers as circuit components to carry out any of the following functions: a) Suppressing or isolating specific harmonic components in voltages and currents. b) Providing electrical isolation from one circuit to another. c) Limiting the currents under fault conditions. d) Increasing or decreasing the voltage or current levels. e) Integrating voltages, currents, or power. f) Providing neutral line, phase shift. The performance of the electronic systems is dependent upon the design of the electromagnetic components that are used. For the aerospace quality hardware, the weight, size, cost, reliability, and efficiency of the electronic systems are substantially dependent upon the design of electromagnetic components.

This paper summarizes progress for the “Integrated Power Unit - Advanced Development” program under contract with the U.S. Air Force at the Air Force Research Laboratory in Dayton, Ohio. This is a 58 month program beginning in February 1996, and ending in December 2000. Figure 1 is a program schedule that identifies major tasks and timing of the phases. The scope of this effort is to design, build, and ground test a highly integrated, air-breathing, electrical power unit which demonstrates the critical design and integration features required for a simple, durable, and reliable Integrated Power Unit (IPU). The IPU must be electrically linked for self starting, main engine electrical starting and as a major source of redundant electric power for the aircraft's main electric power system. Figure 2 shows a mockup of a prototypic IPU design.

Several concurrent trends are forcing a reevaluation of the electrical power quality which is most practically and suitably delivered to aircraft electrical utilization equipment. Military applications have focused on 270 Vdc and the system integration issues of more-electric aircraft. Most civil applications are yet to become very much “more-electric”, though their increasing capacity and electronic load content has invalidated many of the assumptions upon which traditional power quality documents were based. This paper discusses the development of new guidelines for a variety of interface parameters essential to safe, effective application of both constant and variable frequency ac electric power.