Modeling, design and control of DC-DC buck converter

With the developments in renewable energy sources and battery technology, the use of dc current-based energy systems in industry and consumer electronics is increasing day by day. Especially in low power systems such as consumer electronics, it is very important to efficiently convert the ac current taken from the grid to dc current. In such systems, the ac voltages are rectified with the help of a simple rectifier and converted to the dc voltage and the dc voltages obtained are converted to a different dc voltage level with the help of dc-dc converters depending on the usage area of the consumer and the industry. Buck converters, one of these conversion circuits, are used in many areas such as motor driver applications, led lamp drivers, electric vehicle charging stations. In this study, a digital PI controlled buck converter of approximately 10W with 48Vdc input voltage and 12Vdc output voltage that can be fed from a low-power, high-efficiency simple dc source are analyzed and its design are experimentally carried out. While analyzing the converter, important design parameters such as output voltage ripple and inductance current ripple are taken into consideration. The values of the power stage elements are calculated according to the determined design parameters. At the same time, the MATLAB @ Simulink simulation are performed under different loads and the output parameters of the circuit are observed. Circuit element selection criteria are mentioned and circuit elements are selected according to calculated values. A printed circuit board (PCB) are designed using the Altium Designer program. Using TMS320F28379D DSP, the voltage mode control of the circuit are carried out under different loads. The efficiency of the circuit are observed for different input voltage and output load values by establishing an experimental circuit setup.