SOLAR POWER GENERATION SYSTEM

PROBLEM TO BE SOLVED: To obtain a solar power generation system in which the mounting method of a plurality of auxiliary solar cells is optimized and in which the influence of the shadow of the sun due to a partial cloud, the shade of a of a tree or the like is reduced as far as possible, by a method wherein the plurality of auxiliary solar cells are installed additionally and the in solution condition of a main solar cell is grasped precisely. SOLUTION: A solar cell array 1 is composed of a main solar cell 11 in which modules are arranged and of a first auxiliary solar cell 12 and a second auxiliary solar cell 13 which are installed for control use. Since the first auxiliary solar cell 12 and the second auxiliary solar cell 13 are arranged symmetrically with respect to the central axis of the solar cell array 1, the output voltage of the first auxiliary solar cell 12 and that of the second auxiliary solar cell 13 generate a large difference according to intensity of insolution. The output values are inputted to a voltage instruction device 2, and the two values are compared by the voltage instruction device 2 so as to read an absolute value. In the case of this condition, the output voltage may be judged according to a larger output voltage. When a solar power generation system is controlled by using the mean value of the two output values, its accuracy becomes better than in the case in which one out of the two output values is used.