Modeling and control strategy for cascade bi-directional DC/DC converter in Microgrid

In the energy storage system in Microgrid, the voltage of super capacitor drops quickly when the super capacitor is delivering power. In condition that the voltage of DC bus constant, we need to enhance the conversion ratio of DC/DC converter. To avoid the switching devices operating at extremely high or low duty ratios and satisfy the practical requirements of Microgrid, a bi-directional topology is adopted and a cascade connection is proposed. In this paper, modeling and control strategy for n-stage converter are given. Simulation results are presented to verify the control method.