The principal objective of this dissertation is the development of 450W solar array regulator for low earth orbit satellites. For the development, the analysis, design, and test about three items are performed.
The first is the analysis and design of a solar array which is only power source for spacecrafts. The solar array harvests electrical power to operate satellites. The power conversion of the solar array is carried out by control of the operation point using the solar array regulator when the solar array faces the sunlight. Thus, the design of the solar array should comply with not only the power requirement of satellite system but also the input voltage requirement of the solar array regulator. The design requirements of the solar array for low earth orbit satellites are defined, and the means of satisfying these requirements are described. Also, the electrical characteristics are analyzed, which is used for evaluating the performance of the solar array regulator.
The second is the analysis, design, and test of the operation modes of a solar array regulator. The solar array regulator supplies the electric power to the battery and the other units of a satellite by controlling the operating point of a solar array. The solar array regulator performs the maximum power point tracking, power limitation, and constant voltage control. The new maximum power point tracking method that is only composed with analog circuits is proposed and verified to use for spacecrafts. Also, the power limitation method and constant voltage control method using the analog maximum power point tracker is designed and verified to optimize the volume and weight of the solar array regulator by preventing the excessive power conversion and battery over-charge.
The third is the analysis and measurement of the stability of a solar array regulator. The solar array regulator has a reversed input and output variables in comparison with conventional converter. Thus, the new approach for large and small signal analysis is needed despite using buck-converter for a power stage. The steady state analysis of solar array regulator is performed in continuous conduction mode and discontinuous conduction mode. Also, the small signal model of a solar array regulator is established for analysis the stability in continuous and discontinuous conduction mode. The results of the simulation and experiment measurement show the solar array regulator is in stable at continuous and discontinuous conduction modes.
Finally, in this dissertation, the design and analysis for developing 450W solar array regulator is carried out and it is verified by the simulation and experiments.