A hybrid electrical power system for aircraft application

The trend of commercial aircraft today is toward larger size and more electric service power. As the aircraft becomes larger and environmental conditions become more severe, stringent design requirements such as a high degree of reliability, minimum operating cost, and minimum weight are imposed on the aircraft electrical power system. In reviewing the electrical power systems installed in present day aircraft, it is found that despite many improvements, the basic approach of these systems is virtually the same as about 20 years ago. In the light of recent technological advances in various related fields and the change of aircraft electrical power system requirements, a reevaluation of the conventional approach is in order. In recognition of this, a study program was initiated in 1968 by NASA Electronics Research Center to investigate possible improvements to present aircraft electrical power systems for use in future advanced types of aircraft. Study results indicate that many avenues are available for improving the present system, such as variable-speed, constant-frequency generation, optimization of system voltage and frequency, solid-state power switching and control, automatic load management, signal multiplexing, failure prediction, detection, and compensation, to name a few. A detailed discussion of these improvements is beyond the scope of this presentation. This paper specifically presents a projected development trend and depicts an example of a hybrid electrical power system offering reduced weight and improved reliability and maintainability.