Described herein is a system for generating electric power, comprising: an electric-power source (1) having a preferential point of operation; a double-stage inverter (3A, 3B), which transfers the energy from said source to an external a.c.-voltage electrical network (9); a block (5) for identification of the preferential point of operation, which supplies a reference signal according to the conditions of operation of the electric-power source and to the preferential point of operation of said source; a corrector block (10), provided for setting the parameter for control of the boost converter (3A) of the double-stage inverter (3A, 3B) as a function of the reference signal and of a signal of actual operation of said electric-power source, and for maintaining the source in the proximity of the preferential point of operation.