In this work, the real-time mathematical models of electromechanical power systems with semiconductor converters based on the author’s method of the average voltages in the integration step are described. As well as the theoretical basics of the method, the algebraization algorithm of differential equations on a time quantum is described. This time quantum in the hybrid model is synchronized with the time quanta of signal samples of the physical part of the model. In the hybrid model, only algebraic equations of electromechanical power systems are present. Software and technical applications of the hybrid models of energy-generating blocks for selected thermal and nuclear power plants are described. In the process curve courses obtained and projected in this paper, the author’s hybrid models are illustrated. In the existing models, the nonlinearity of the electric machines and the semiconductor converters are taken into account. The numerical stability of the method of average voltages in integration step—in the sense of the resistance to computer calculation disturbances—is proven.