Optimization of synchronous buck-boost DC-DC switching converter

This paper presents a high-efficiency non-isolated synchronous buck-boost DC-DC switching converter. The circuit is made to operate in Discontinuous Conduction Mode (DCM)of operation for minimum inductor value, to reduce size and cost of the converter. A snubber capacitor is used across the switch to minimize turn-off loss. The power dissipation through snubber capacitor and inductor is minimized by proper selection of its value, hence improves the efficiency of the converter. Complementary gate signals are used to control the ON and OFF of main and auxiliary switch. By use of DCM of operation, complementary gate signals control scheme and snubber capacitor, turn-on loss is minimized. State space averaging method is used to obtain control-to-current transfer function. Using the transfer function module, Proportional Integral Derivative (PID) controller is tuned using PID tuner available in simulink control design block to regulate load voltage and load current for change in inductor reference current(I*), change in load and change in input voltage. The modules are verified using MATLAB simulink simulator.