A simple control method of open-circuit voltage for the FPGA-based solar array simulator

Solar panels are widely used not only in terrestrial applications, but also are the main source of energy for spacecraft. The space solar array simulator (SSAS) for space power systems testing is generally used the linear power topology to deal with the power, because of its fast dynamic performance and good simulation accuracy. However, current-output linear power stage is very difficult to control the open-circuit voltage accurately, this paper presents a novel and simple open-circuit voltage controlled method with adding a dummy load of fixed resistance value paralleling output terminal of the FPGA-based space solar array simulator, and the digital controller give linear current source current reference with adding corresponding offset current reference, so that the flow of current through the dummy branch is controlled. By controlling the current value of the dummy load branch, it is easy to achieve precise control of the open circuit voltage in open condition. A prototype is built achieving the precision open-circuit voltage output in the range of 15 V to 60 V, with a 8.5 A peak output current and a 510 W peak output power. The experimental results show that the proposed method can obtain a good accuracy without influencing the high dynamic response of switching between short-circuit and open-circuit at 10 kHz.