A Novel Working Point Control Method with Solving the Nonlinear Control Problem of I-V Outer-loop for Space Solar Array Simulator

Abstract

Space Solar Array Simulator (SSAS) is widely used in non-terrestrial testing application where need the SSAS have high dynamic performance, high simulation accuracy, and high fill-factor I-V curve simulation capability. In general, the energy source of a satellite power system from the solar array panel with the material of the triple junction GaAs which output I-V power curve with high fill factor. However, the general commercial simulator products cannot simulate the I-V curve with high fill factor because the higher the fill factor of the I-V curve is, the more severe the nonlinear effect of the I-V outer-loop is. This paper proposes a novel I-V outer loop control method with working point control method that control the output current and output voltage simultaneously based on coordinated working of two power units, the current control unit (CCU) and voltage control unit (VCU), solving the nonlinear control problem of the I-V curve with high fill factor perfectly. The I-V outer loop includes two parts; the first part of the input is the SAS output voltage information, and output the expected operating current reference voltage information required by the CCU. And the second part of the input is the SAS output current information, the output is the desired control voltage reference information required by VCS. Through the coordination of the two parts of the I-V outer loop with CCU and VCU, the SAS can directly output the desired working points on the I-V curve whatever the nonlinear characteristics of the I-V curve is. Finally, under the simulation experiment of 60V open-circuit voltage and 2A short-circuit current, it is verified that the control method can simulate any nonlinear I-V curve, and it can also show good dynamic response performance under the 1-kHz load switching frequency.