Integrated electronics SCLAR array control unit

This paper describes the implementation and initial test results for a unique digital-analog solar array control concept wherein portions of the circuitry are electrically and physically integrated with the solar array subsystem. The concept has been developed to capitalize on the high efficiency and reliability advantages of the shunt regulator while minimizing the attendant thermal dissipation of excess array power. Thermal dissipation is minimized by digitally switching out those portions of the array which are not required by the load. The specific design described is for a nominal 2 kW unit which illustrates the control approach for a broad power range extending from 0.5 kW to greater than 20 kW. Radiation hardening was initial design goal and has been included since the beginning of the conceptual design phase. Computer circuit analysis and radiation simulation testing have been employed extensively to predict and verify unit performance in the total environment. Areas where this factor had a major influence on circuit design or component selection are discussed as well as the special circuits which have been included for protection against the radiation excited array.