Modeling and design of an LLC resonant converter for a wide voltage conversion ratio applications

LLC Resonant converters provide soft-switching capabilities enabling high switching frequencies and high efficiency. A low-quality factor design operating below resonant frequency is preferred for wide voltage-gain applications to reduce the required range of operating frequencies. Phase-shift modulation can be used in conjunction with frequency modulation to further narrow the operating frequency range. A first harmonic analysis-based approach has high inaccuracies in estimating capacitor voltage, inductor current, and voltage gain, which are critical parameters to design the converter and estimate the losses when phase-shift modulation is employed. This thesis presents a state-plane-based modeling framework to accurately analyze the converter when both frequency and phase-shift modulation are used. The proposed model is then used to highlight the power density versus efficiency trade-off obtained by utilizing phase shift as an additional control variable for an electric vehicle battery charging application. The accuracy of the model is verified by experiments on a 10kW SiC-based prototype. Two converters are designed using the trade-off curve, one employing only frequency modulation and the other using both frequency and phase-shift modulation. These two converters achieve the same efficiency over the constant current battery charging mode but, the addition of phase-shift modulation reduces the transformer’s size by 22% and its weight by 28%.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Maheshwari, Anuj

Contributors dc:contributor

• Banerjee, Arijit

• Llc Resonant Converter
• Wide-output Range
• Efficiency
• Power Density
• State-plane Analysis

Statement dc:rights

• Copyright 2022 Anuj Maheshwari

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/117842

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F117842