No abstract

An algebraic transformation to the commonly used diode equation of a solar cell produces an equation ideally suited for use in modeling power systems incorporating photovoltaic solar arrays. The transformed equation predicts cell current as a function of voltage to high precision (1 part in 10') within three iterations for all practical conditions. The transformed model requires four parameters derived from data that are easily obtained from commercial cells under illuminated conditions: short circuit current, open circuit voltage, and the current and voltage at the maximum power point. Determining the parameters of the cell model requires an implicit procedure, which for the transformed model converges for the entire range of possible values. The significant advance in convergence speed and reliability enables the model to support real-time simulations with hardware-inthe-loop and software-in-the-loop as well as faster-thanreal-time simulations. Applications of this model to realtime simulation of the International Space Station for training the astronauts and flight controllers are included.