This paper performs a modeling of an isolated full bridge boost converter that suits the system level studies of power electronic -based systems. For system level studies, in which large signal models must be developed, linearized average value models are invalid. Large signal analysis can be carried out by nonlinear State Space models. In this paper generalized state space averaging method is adopted to include ripple modeling for higher accuracy. The obtained model is compared to a number of other averaging methods and also verified by the detailed switching model. Nonlinear control is carried out by feedback linearization approach. Large signal stability and zero steady state error of the closed loop system are validated by simulation results of the detailed and generalized state space models.