Constant-frequency capacitor current hysteresis control of buck converter using reconstructed ideal-capacitor voltage

Weiguo Lu, Shaoling Li, Yidi Yang, Zhaoyang Zhao, Herbert Ho Ching Iu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

For the case with electrolytic capacitors as the output capacitor, the traditional capacitor current hysteresis (CCH) controlled buck converter is always in over-damping state due to the ESR, and has a poor dynamic performance. Moreover, there is a problem of variable switching frequency operation in the CCH controlled buck converter. To solve these problems, an improved constant-frequency CCH (CF-CCH) control scheme using the reconstructed ideal-capacitor voltage is proposed in this paper. The ideal-capacitor voltage is reconstructed through a low-pass filter and an integrator, and introduced into the control loop to replace the actual output voltage. In the proposed CF-CCH control scheme, the damping ratio is designed as the optimum value 0.707, which is in under-damping state. Furthermore, the switching frequency is kept constant by disturbing the hysteresis bands with a pair of periodic ramp signals. In addition, the circuit design of the proposed CF-CCH control scheme is presented. Finally, the validity and superiority of the proposed CF-CCH control scheme are verified by simulation and experiments.

Original languageEnglish
Article number8536906
Pages (from-to)7916-7926
Number of pages11
JournalIEEE Transactions on Industrial Electronics
Volume66
Issue number10
DOIs
Publication statusPublished - 1 Oct 2019

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