Open AccessOpen‐loop transfer functions of buck–boost converter by circuit‐averaging technique
Author(s) -
Saini Dalvir Kaur,
Kazimierczuk Marian Kazimierz
Publication year - 2019
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2018.5514
Subject(s) - buck converter , duty cycle , transfer function , control theory (sociology) , pulse width modulation , buck–boost converter , small signal model , boost converter , voltage , power (physics) , signal (programming language) , transient (computer programming) , output impedance , electrical impedance , computer science , physics , engineering , electrical engineering , control (management) , quantum mechanics , artificial intelligence , programming language , operating system
This study shows the derivation of the power‐stage transfer functions and input and output impedances of a buck–boost pulse width‐modulated (PWM) dc–dc converter operating in continuous‐conduction mode. The expressions are derived using the small‐signal model obtained by the circuit‐averaging technique. Using the small‐signal dynamic model, both transient and frequency domain characteristics are determined. An example buck–boost converter with the following specifications was considered: supply voltage 12 V, output voltage 5 V, switching frequency 200 kHz, and output power 10 W. The modification of the power‐stage transfer function to include the time delay between the MOSFET gate drive and the duty cycle is considered and is modelled by the first‐order Padè approximation. The theoretical predictions were verified by experiments and excellent agreement between the results was observed.