Analog computer simulation of an aircraft parallel A-C generating system

THE OBJECT of this paper is to present a formulation of the dynamics of complex aircraft electromechanical systems using analytical representations of components suitable for analog computation. The ability of the computer to predict system performance as well as to provide a means for system analysis and synthesis is demonstrated by correlating the results of equipment tests and computer simulation tests in the case of the parallel a-c electrical generating system used in the B-47 type of aircraft. This comparison is made to insure that all relevant information has been included in the simulation and that the simplifying assumptions adopted in the analysis are reasonably warranted. The approach used to set up the representations is detailed and generalized, with emphasis on the development of an organized procedure for studying complex aircraft electric systems rather than on providing the simplest system representation which may be valid for just one particular case. A system representation using a cascaded sequence of linear gains and time constants with associated feedbacks can give but a crude indication of actual system performance. Similarly, a representation of the dynamics of parallel alternators in terms of equivalent masses and springs, or one using the ordinary stability criteria developed for central station practice, is inadequate.