The problem of the output voltage stabilization of buck converter is considered in the paper. It is assumed, that the stabilizer serves as power supply for inductive and resistive load, which can be described by differential equation with time-varying coefficients. The value of the equivalent inductance and resistance are unknown, but they belong to the class of bounded functions with several bounded derivatives with known bounds. According to this bounds, the influence of the external load is described as additive disturbance, which excites the right hand side of the differential equation of the control plant. By using the, so-called, “vortex” algorithm, the control input synthesis is developed in the paper, which theoretically provides asymptotical stabilization of the output voltage error to zero. The formal conditions for the parameters of the converter and the electrical load are derived. The theoretical results may be used for designing of the buck converters with the desired output characteristics. The proposed control scheme is developed for control of the input voltage of the electric drives. The simulation results show the efficiency of the basic control law.