TY - JOUR
T1 - Reconsideration of loop gain and its measurement in DC-DC converters
AU - Ruan, Xinbo
AU - Xiong, Chun
AU - Li, Xin
AU - Xiong, Xiaoling
AU - Jin, Qian
AU - Sha, Mengke
AU - Tse, Chi K.
N1 - Funding Information:
Manuscript received May 27, 2018; revised August 8, 2018 and September 18, 2018; accepted September 20, 2018. Date of publication September 30, 2018; date of current version May 2, 2019. This work was supported by the National Natural Science Foundation for Distinguished Young Scholars under Award 51525701. Recommended for publication by Associate Editor T. Suntio. (Corresponding author: Xin Li.) X. Ruan, X. Li, Q. Jin, and M. Sha are with the Center for More-Electric-Aircraft Power System, College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China (e-mail:, ruanxb@ nuaa.edu.cn; [email protected]; [email protected]; shamengke@ nuaa.edu.cn).
Publisher Copyright:
© 1986-2012 IEEE.
PY - 2019/7
Y1 - 2019/7
N2 - Two measurement schemes, namely, the modulation signal perturbation scheme and the pulse perturbation scheme, have been used for evaluating the loop gain of dc-dc converters. However, the two measured loop gains do not give consistent results due to the use of different forms of the injected small perturbation signal, and the difference in the two schemes cannot be distinguished by the usual averaged model. In this paper, the two loop gain measurement schemes are analyzed based on an extended-frequency-range small-signal model. Expressions of the loop gain are derived and their use in stability assessment and derivation of closed loop transfer functions is demonstrated. A sample-and-hold scheme is proposed as a simple alternative implementation of the pulse perturbation scheme. Finally, experimental prototypes of buck, boost, and buck-boost converters are tested for verification of the analytical results and the effectiveness of the sample-and-hold scheme.
AB - Two measurement schemes, namely, the modulation signal perturbation scheme and the pulse perturbation scheme, have been used for evaluating the loop gain of dc-dc converters. However, the two measured loop gains do not give consistent results due to the use of different forms of the injected small perturbation signal, and the difference in the two schemes cannot be distinguished by the usual averaged model. In this paper, the two loop gain measurement schemes are analyzed based on an extended-frequency-range small-signal model. Expressions of the loop gain are derived and their use in stability assessment and derivation of closed loop transfer functions is demonstrated. A sample-and-hold scheme is proposed as a simple alternative implementation of the pulse perturbation scheme. Finally, experimental prototypes of buck, boost, and buck-boost converters are tested for verification of the analytical results and the effectiveness of the sample-and-hold scheme.
KW - Extended-frequency-range small-signal model
KW - loop gain
KW - modulation signal perturbation scheme
KW - pulse perturbation scheme
KW - sample-and-hold
UR - http://www.scopus.com/inward/record.url?scp=85054385069&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2018.2873074
DO - 10.1109/TPEL.2018.2873074
M3 - Journal article
AN - SCOPUS:85054385069
SN - 0885-8993
VL - 34
SP - 6906
EP - 6921
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
IS - 7
M1 - 8477169
ER -