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PWM and PFM Hybrid Control Method for LLC Resonant Converters in High Switching Frequency Operation.

Authors :
Park, Hwa-Pyeong
Jung, Jee-Hoon
Source :
IEEE Transactions on Industrial Electronics. Jan2017, Vol. 64 Issue 1, p253-263. 11p.
Publication Year :
2017

Abstract

High switching frequency is an effective method to improve power density for LLC resonant converters. However, conventional digital controllers, such as general-purpose digital signal processors and microprocessors, have limited frequency resolution, which induces high primary- and secondary-side current variation and leads to poor output voltage regulation. In this paper, a hybrid control method combining pulse frequency modulation (PFM) and pulse width modulation is proposed to overcome the limited frequency resolution issue. The proposed hybrid control method focuses on steady-state operation, and its operating principles are introduced and analyzed. In addition, the proper magnetizing inductance and dead time duration are derived to ensure that the power <sc>mosfet</sc>s achieve zero voltage switching with the proposed control method. The improved voltage regulation performance is compared with the conventional PFM control and verified through simulation and experimental results using a 240 W prototype converter operating at a switching frequency of 1 MHz. [ABSTRACT FROM PUBLISHER]

Details

Language :
English
ISSN :
02780046
Volume :
64
Issue :
1
Database :
Academic Search Index
Journal :
IEEE Transactions on Industrial Electronics
Publication Type :
Academic Journal
Accession number :
120167618
Full Text :
https://doi.org/10.1109/TIE.2016.2599138