Development of a bi-directional DC/DC converter for inverter/charger applications with consideration paid to large signal operation and quasi-linear digital control

In this paper, a low-power bidirectional DC/DC converter for inverter battery charger applications is considered. Initially, a galvanically isolated and synchronously rectified DC/DC converter topology is prototyped and its stationary performance evaluated. Next, a nonlinear dynamic model of the converter is derived using a state space averaging method. The dynamic model is nonlinear in the sense that it is a function of both converter duty cycle and load. The nonlinear model is then digitized and a proposed simulation algorithm derived and successfully validated against empirical data from the prototype converter. Finally, the large signal circuit dynamics are analyzed and an adaptive, fully digital pole placement controller is examined in adaptive and nonadaptive modes of operation.