AbstractNowadays PID regulator, power system stabilizer (PSS) and nonlinear control were widely used in multi-machine power system excitation control. This paper will use the nonlinear robust control theory to design the excitation controller, in order to realize the decentralized robust control and improve stability of the system. Simulation results show that the nonlinear robust excitation controller is very effective for the improvement of system stability and disturbance attenuation compared with the PSS and the traditional PID controller.