LLC Resonant Converter Based Single-stage Inverter with Multi-resonant Branches

This paper presents a single-stage inverter with variable frequency modulation (VFM) based on LLC resonant converter. And LLC converter is a common topology of dc/dc conversion. LLC resonant converter can achieve high efficiency and soft-switching performance. Since the dc gain curve of the single-resonant LLC converter is flat when the switching frequency is larger than the resonant frequency, namely fs>fr, an additional L-C series resonant branch is paralleled to the original resonant tank to introduce higher-order-harmonic resonant current and a zero-gain point to the gain curve. Higher-order-harmonics help to deliver power and the zero-gain point enlarges the gain range which improves output THD and reduces the switching frequency range. A 1.2 kW prototype is built to demonstrate the performance of the proposed inverter. Zero-voltage-switching (ZVS) and zero-current-switching (ZCS) are achieved on the primary side and secondary side, respectively. And 97.3% efficiency and 2.17% voltage THD are achieved at full load condition, while 97.2% efficiency and 3.2% voltage THD are achieved at half load condition.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

power electronics

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2022

Author dc:creator

• Jiao, Dong

Chair dc:contributor.committeechair

• Lai, Jih-Sheng

Committee members dc:contributor.committeemember

• Jia, Xiaoting
• Dong, Dong

• single-stage inverter
• multi-resonance
• LLC resonant converter

Statement dc:rights

• Creative Commons Attribution 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by/4.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/109563

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/109563