Current Injected Equivalent Circuit Approach to Modeling Switching DC-DC Converters

A new current injected equivalent circuit approach (CIECA) to modeling switching dc-dc converter power stages is developed, which starts with the current injected approach and results in either a set of equations which completely describe input and out-put properties or an equivalent linear circuit model valid at small signal, low frequency levels. This approach to modeling switching dc-dc converter power stages has the merits but not the demerits of both the electronic equivalent circuit state space average approach and the current injected control type approach, namely, 1) the modeling is very clear and is simple whether the converter operates in continuous or discontinuous inductor conduction modes, 2) the modeling results in an equivalent circuit which is very close to the actual converter, and 3) the equivalent circuit can be used directly in the computer for theoretical predictions like SPICE, etc.     

Microprocessor-Controlled Digital Shunt Regulator

A new approach to the design of power systems is presented in which a microprocessor is used as a controller for a digital shunt regulator (DSR). This approach meets the demands of future space and ground missions, i. e., high efficiency, high reliability, low weight, low volume, increased flexibility, and less development time. This approach responds to future demands by permitting realtime modification of system parameters for system optimization. This feature is especially important in the event of an anomaly. As the microprocessor need not be dedicated to the DSR, it can simultaneously be used for battery management and for charge regulator/discharge regulator control. This approach also reduces the component count, simplifies assembly and testing of the unit, results in significant time saving, and increases the reliability.     

Enhanced Power Generation of GSS4PS by Optical Solar Reflectors

A novel arrangement is proposed to enhance the power generation capabilities of a gravitationally stabilized solid-state-satellite solar-power station (GSS4PS) spherical solar collector. The unilluminated portion of a GSS4PS is illuminated by employing 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 practical realization of this concept will enhance the power generation capability of the GSS4PS and simultaneously reduce the weight per unit power and cost per unit power in GSS4PS spherical solar collectors.     

Modeling and Design of Switching Regulators

Various building blocks of a switching regulator are described in detail and mathematical models are developed for all building blocks in terms of transfer functions, which enable one to design a switching regulator for stability, desirable bandwidth, line rejection, and transient response. A step-by-step procedure to design compensation is illustrated using two examples. Various networks for compensation and their transfer functions are presented which the author hopes will be very handy to use and will become the reference source.     

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.     

A New Resonant Mode Amplifier Produces Clean AC Power

A new resonant mode power amplifier design is described which has a number of advantages over the power amplifiers available today. In particular, it has low or no EMI because of the nature of its operation. The new amplifier design is based upon a resonant mode dc-dc converter used in a push-pull configuration. All the advantages of the resonant mode power converters, such as high efficiency, small size and weight, excellent dynamic performance, low or no EMI (compared to PWM switch mode power converter), etc., are present in this new design.     

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