In this doctoral thesis synthesis of nonlinear IDA power system stabilizer is made. IDA stabilizer also includes functionality of automatic voltage regulator. The basis for nonlinear IDA power system stabilizer constructing is salient pole synchronous generator nonlinear model of third order, synthesis of which is analyzed in detail. For IDA stabilizer synthesis it is convenient to represent synchronous generator mathematical model as PCH system. Apart from known procedure of IDA regulator synthesis that gives power system stabilizer algorithm, generator voltage feedback is also implemented and functionality of automatic voltage regulator is achieved. After IDA stabilizer synthesis, asymptotical stability of system which consists of salient pole synchronous generator connected to electrical power system is proven. Simulations of system with implemented IDA power system stabilizer are made in Matlab software. In simulations salient pole synchronous generator seventh order model is used for IDA stabilizer testing. Simulation model gives possibility of testing generator voltage reference value change, generator mechanical power change and occurrence of short circuit on generator bus voltage. Simulation results prove that generator voltage reference value tracking is successfully realized. Control algorithm robustness is proven by regulation quality testing in case of large disturbance, such as short circuit on generator bus and generator operating point change. Regulation quality comparison for IDA stabilizer and classical linear regulators show that linear regulators have better regulation quality in case of small disturbances. In case of large disturbances IDA stabilizer gives better regulation quality comparing to classical linear regulators. Stability of system with implemented IDA stabilizer in generator capacitive operating mode is also proven.