PV system modeling and a global-planning design for its controller parameters

The conventional mathematic model of PV (Photovoltaic) cells contains logarithmic terms, which is not conducive to derivation calculation in small-signal modeling. The parameters of PV system are coupling due to its double-loop control method, and it´s hard to precisely choose controller parameters. To solve these two problems above, this paper is based on PV system connected to an infinite power grid, uses the linear-fitting model of PV cells which is conducive to derivation instead of the original engineering one in small-signal modeling, and analyses the small-signal stability of the entire system. Meanwhile, a global-planning design for controller parameters is proposed to globally provide the optimal controller parameters. Simulation results show that the linear-fitting model of PV cells is very similar to the original engineering one, and the proposed design for controller parameters can provide a solution to calculate the global optimization.