CIECA: Application to Current Programmed Switching Dc-Dc Converters

Sundstrand Advanced Technology Corporation The current injection equivalent circuit approach (CIECA) to modeling switching converter power stages is extended to model the current programmed converter power stages operating in fixed frequency, continuous inductor conduction mode. To demonstrate the method, modeling is carried out for the buck, boost, and buckboost converters to obtain small-signal linear equivalent circuit models which represent both input and output properties. The results of these analyses are presented in the form of linear equivalent circuit models as well as transfer functions. Though current programmed converters exhibit single-pole response, the addition of artificial ramp changes converters to exhibit well damped two-pole response. This has been investigated for the first time using CIECA. The results of these analyses are presented in the form of linear equivalent circuit models as well as transfer functions.     

Enhanced Power Generation by Optical Solar Reflectors on Geostationary Spinners

A novel arrangement is proposed to enhance the power generating capabilities of a spin stabilized geostationary satellite (spinner). The unilluminated solar array area of the usual spinner (as sunlight falls on only one side) is illuminated by employing despun optical solar reflectors. The different mechanisms required for implementation of this arrangement are already space proven. The detailed study of this arrangement made by the authors reveals that the practical realization of this concept will enhance the power generating capability of the spinner and simultaneously reduce the weight (per unit power) and cost (per unit power) in such spinners.     

TOPEX/Poseidon: Electrical power system-lessons learned

The main objective of the TOPEX/Poseidon Spacecraft is to monitor the world's oceans for scientific study of weather and climate prediction, coastal storm warning and maritime safety. The operational conditions of this satellite imposed challenging requirements for the on-board Electrical Power System (EPS), Going through various phases of its development and on-orbit performance verifications, there were certain events and/or circumstances we would have liked to avoid. Some circumstances were avoided with preventative measures, other potentially detrimental events were not. Thus, a number of valuable lessons were learned which are presented in this paper     

Resonant power supplies: their history and status

The various types of converter are described, and the history of resonant power supplies is briefly sketched. The differences between pulse-width-modulated (PWM) switch mode power supplies and resonant power supplies are discussed. Single-switch, multiple-switch, and series and parallel resonant converters are examined. The control of resonant converters is addressed. Hardware is briefly considered     

The onset of converging and diverging shock waves in non-equilibrium gas flows

In this work, the effects of thermodynamical influences and that of wave front curvature on the propagation of finite amplitude waves of arbitrary shape and their consequent formation into shock waves are examined.