Abstract—Two port network based modeling approach is used to obtain the analytical expressions for dc-dc buck converter. The analytical expressions obtained include the effect of parasitic elements. The parasitic resistance associated with the filter capacitor and inductor has a significant influence on the converter’s frequency responses, so a very simple and systematic procedure has been introduced for the computation of series resistance associated with capacitor and inductor from measured frequency responses. Further, the obtained small signal model is validated through experiment. Once the analytical expressions are available, a prototype of the converter is implemented and frequency responses are measured for various parameters know as g-parameters both in open as well as closed loop mode. The experimental results are compared with those obtained using modeling and it is found that the measurement results match the analytical results. The frequency response measurement based validation of small signal model, presented for dc-dc buck converter, can be used for any type of dc-dc converter working in an open or closed loop configuration.

Index Terms—DC-DC converter, frequency response, g-parameters, parasitic elements, transfer function.

Husan Ali, Xiancheng Zheng, Shahbaz Khan, and Haider Zaman are with Department of Electrical Engineering, School of Automation, Northwestern Polytechnical University, Xi’an, 710072, China.
Muhammad Saad is with Department of Electronics and Control Engineering, Chang’an University, Xi’an, 710064, China.

Cite:Husan Ali, Xiancheng Zheng, Shahbaz Khan, Haider Zaman, Muhammad Saad, "Frequency Response Measurements Based Analysis of Small Signal Model of DC-DC Converter," International Journal of Computer and Electrical Engineering vol. 10, no. 2, pp. 72-84, 2018.