Approximation of a photovoltaic module model using fractional and integral polynomials

In this paper, a novel method is presented using fractional polynomials to approximate the performance for a PVM where the shape, boundary conditions and performance of the physical system are satisfied. The use of fractional polynomials will provide an analytical solution to determine the optimal voltage, Vop, optimal current, Iop, and maximum power, P_max for the PVM operation. Also, this paper proposes a second method to approximate a fractional polynomial by a sufficiently close integer polynomial. Several examples are shown and verified using the manufacturer data sheets of different PVM´s. Finally, the proposed methods are excellent to approximate the PVM´s I-V Curves and provide a different way to approximate analytically the PVM´s optimal voltage to produce the PVM´s maximum power that it is not possible to solve using differential calculus.