Solar probe plus (SPP) dynamic solar array simulator
|Keywords||Attitude control; Control theory; Digital signal processors; Electric power systems; Flight control systems; MATLAB; NASA; Orbits; Probes; signal processing; Simulators; Software testing; Solar cell arrays; Space flight; Spacecraft power supplies; Vibrations (mechanical); Wings; Parker Engineering|
|Abstract||The Solar Probe Plus (SPP) mission, under NASA’s Living With a Star program, will fly a spacecraft (S/C) through the sun’s outer corona with orbit perihelia that gradually approach as close as 9.86 solar radii from the center of the sun. The mission will gather data on the processes of coronal heating, solar wind acceleration, and production, evolution, and transport of solar energetic particles. The S/C is powered by two actively cooled photovoltaic solar array (S/A) wings. Because of the extreme environments near the sun, the S/C body is protected behind a solar shield, which the wings will utilize to provide shading in the penumbra behind the solar shield the wings will also tilt at a high angle of incidence to the sun. The S/A power and temperature are extremely sensitive to the wing angle, S/C pointing variations, mechanical vibrations, sun distance, and other environmental disturbances in these harsh conditions. A novel S/A control algorithm autonomously positions the wings to optimize the thermal load while maintaining adequate electrical power.|
A dynamic solar array simulator (DSAS) is required to adequately test and verify the S/C hardware and software controls. A fast serial link provides simulated data of the incident radiant flux on the S/A wings for any wing angle, S/C attitude, and shadow condition during any point in the mission. To emulate flight solar cells, the DSAS creates the entire nonlinear current-voltage (I-V) profile of each string under any illumination condition of the array using code generated from MATLAB/Simulink models. Multiple power supplies are dynamically controlled by using a digital signal processor to operate anywhere on the I-V profile. In addition, the I-V profiles are continuously updated in real time to account for illumination and temperature changes to the solar cells.
This DSAS provides the ability to test the control laws of the S/A wings in conjunction with the S/C attitude control system and flight hardware in flight-like conditions. The S/A simulator models, interfaces, control algorithm, limitations, and requirements are presented in detail. Closed-loop test results are provided to demonstrate hardware and software implementation of the DSAS.
© 2014 by the American Institute of Aeronautics and Astronautics, Inc.
|Year of Publication||2014|
|Journal||12th International Energy Conversion Engineering Conference, IECEC 2014|
|Number of Pages|