Abstract—The problem of controlling a steam generator is considered, taking into account restrictions on the phase variables and control under the effect of external uncontrolled disturbances. To synthesize the control law, a block approach is used with the formation of linear local relationships with saturation, which makes it possible to take into account restrictions on phase variables and control when choosing feedback parameters. Under conditions of incomplete information about the state vector and under the effect of external disturbances, an observer of states and disturbances is synthesized, which makes it possible to obtain estimates of unknown signals with the given accuracy. The efficiency of the proposed algorithms is confirmed by the results of numerical simulation.