Excitation Control of Synchronous Machine Using Dynamic Inversion Control

Excitation control of synchronous machine is done in order to keep the terminal voltage constant. This paper describes the advantage of using a nonlinear technique called Dynamic Inversion (DI) in order maintain the voltage at the terminals constant. An excitation model which includes the excitation system stabilizer (ESS) and the transient gain reduction (TGR) blocks is considered. The reference voltage initially is varied which is done in order to bring the terminal voltage to a specified value. Then, an undesirable change in the reference voltage is assumed. The variation in the terminal voltage is observed. It has been found that the nonlinear technique used here is quite robust. In Dynamic Inversion (DI) technique, zero error dynamics is enforced and the actual output, which is the terminal voltage of the machine, is forced to follow the desired output. The main objective is to maintain the terminal voltage constant, irrespective of any undesirable variations in the reference voltage. The robustness of the controller is also checked by introducing the perturbations twice in the simulation study. The results are found to be satisfactory.