hassan moghbelli - Assistant Professor, Arak University of Technology
shahab sabzi - MS Student, Arak University of Technology

Power Converters are essential parts of power circuits; therefore a lot of attention must be paid to design a controller for these devices. In this paper, a DC-DC bidirectional buck-boost converter controller is designed using switching function extraction method based on lyapunov stability function. Using lyapunov stability function makes sure that proposed system remains globally and uniformly stable in all operational conditions. Switching function extraction also, is an appropriate method in controlling switching devices, in which duty cycles of switches are calculated mathematically and applied to the system that leads to achievements of control's purposes. Bidirectional buck-boost converter in this paper is analyzed based on large signal averaged modeling that is another innovation of the paper. DC-DC converter is used to charge an ultracapacitor using a capacitor and vice versa. Since bidirectional converter has two operational modes, an energy management system is applied to the system to change to modes at required times. In the end, results of simulation confirm the proposed method.

DC-DC converter, Buck-Boost, Lyapunov Stability Function, Switching Function, Ultracapacitor