The purpose of this paper is to present an improved model based controller for a power turbine generators (PTG) on shipboard grid system that is employed by an identification method on the basis of an overall system model. The proposed controller is evaluated by comparing it with the conventional controller. Furthermore, the proposed controller is evaluated in a prototype. In the simulation result using the proposed controller, a limit speed overshooting as a transient response is improved by more than 25% In the prototype test, a limit frequency overshooting is 0.60% and a settling time is 3.8s. Hence, the proposed controller is confirmed to have excellent property.