Inner Intrinsically Safe Criterion and Design Considerations of Buck Converter Based on Equivalent Inductance

Abstract

To obtain the intrinsic safety criterion of the Inner-intrinsic-Safety-Buck-Converter (ISBC) based on equivalent-inductance to guide its optimal design, the Inductor Disconnected Discharge (IDD) behavior of ISBC is researched, and the Equivalent-Simple-Inductive-Circuit (ESIC) based on the equivalent inductance is defined. According to ESIC based on the equivalent-current and the energy equivalence, the expression of the equivalent inductance L_ei is derived. The effect of the inductance L, the capacitance C, the input voltage V_i and the load resistance R_L on L_ei is deeply studied, and it’s pointed out that L_ei increases with the increase of V_i, L, C, and R_L, respectively. According to the minimal ignition current curve of the Simple-Inductive-Circuit (SIC), the nonexplosive intrinsically safe criterion based on L_ei is proposed. Combining the proposed criterion, the output ripple voltage and the expression of L_ei, the design region of the capacitance and inductance of the Buck converter meeting the demands of both inner intrinsic safety and electric performance is obtained. The feasibility of the design method and the proposed criterion is proved by the simulation and experimental results.

Keywords:

• buck converter
• inner intrinsically safe criterion
• equivalent inductance
• design method

Acknowledgments

This work is supported by the National Natural Science Foundation of China (51777167, 51604217).

Additional information

Notes on contributors

Shulin Liu

Shulin Liu received the B.S. degree from Sichuan University, Chengdu, China, in 1985, M.S. degree from Xi’an microelectronics institute and Ph.D. degree in electrical engineering from Xi’an University of Science and Technology, Xi’an, China, in 1988 and 2007, respectively. He received the excellent doctoral dissertation in Shaanxi Province in 2009. He is currently a professor in Dept. of Electrical Engineering and also is a tutor of PhD students. He is the Chinese Society of special power supply IPCC Council members, China Ex Electrical Expert Committee, Shaanxi Province IC Industry Association. He has undertaken three National Natural Science Foundation projects of China, two Special projects of Ministry of Science and Technology, one Technology Research project of Shaanxi Province and two Innovation Fund projects of Xi’an City in China. He holds 30 Chinese patents. He has received Science and Technology Award for 11 times. He has published six books and over one hundred technical papers in journals and conferences. His research interests include switching converters, PFC circuits, modeling and control of converters, design of integrated circuits and intrinsically safe circuits.

Hao Wu

Hao Wu received the Bachelor’s degree in 2015 from the Xi’an Kedagaoxin University. He is currently working toward the Master’s degrees in the School of Electrical and Control Engineering, Xi’an University of Science and Technology. His main research interest is the intrinsically safe circuits.

Chaoying Wang

Chaoying Wang received the Bachelor’s degree in 2016 from the Anhui institute of Science and Technology. She is currently working toward the Master’s degrees in the School of Communication and Information Engineering, Xi’an University of Science and Technology. Her main research interest is the intrinsically safe circuits.

Shen Nie

Shen Nie received the Master’s degree in 2018 from the School of Electrical and Control Engineering, Xi’an University of Science and Technology. His main research interest is the intrinsically safe circuits.

Lili Qi

Lili Qi received the Master’s degree in 2016 from the School of Electrical and Control Engineering, Xi’an University of Science and Technology. Her main research interest is the intrinsically safe circuits.