VARIABLE STRUCTURE AND ADAPTIVE-CONTROL OF A SYNCHRONOUS GENERATOR

Damping of synchronous generator oscillations has been investigated by using three types of controllers, i.e., the PI (proportional-integral) controller, the model reference adaptive controller (MRAC) and the variable-structure model-following controller (VSMFC). It was found that the PI controller fails to accomodate itself to the situation where there is a significant change in generator loading conditions. The MRAC greatly improves the dynamic responses of the generator over a wide range of opearating conditions by minimizing the error in the responses obtained from the plant with a specified reference model. The damping of the generator is further improved by the VSMFC, which reduces the sensitivity of generator responses relative to plant parameter variations by providing sliding-mode operations.