Closed-form design optimization for LLC converters with wide output voltage range based on FHA.

Area of Science:

• Electrical Engineering
• Power Electronics
• Converter Design

Background:

• Wide input/output voltage ranges in LLC resonant converters present significant design challenges.
• Traditional numerical optimization methods for converter design are computationally intensive.
• Achieving regulation over wide output voltages requires higher inductance ratios and broader switching frequencies.

Purpose of the Study:

• To develop a novel, computationally efficient design optimization strategy for LLC resonant converters.
• To establish closed-form analytical equations for systematic and non-iterative optimal design.
• To provide a framework for analyzing design trade-offs in wide-range converters.

Main Methods:

• Derivation of closed-form analytical equations for LLC resonant converter design.
• Development of a step-by-step procedure for optimal parameter determination.
• Validation through simulation of a 495 W LLC converter with wide input (320-370 V) and output (35-165 V) ranges.

Main Results:

• The proposed analytical method enables optimal LLC converter design without numerical solvers.
• The methodology is computationally efficient and systematic.
• Simulated 495 W converter achieved full output voltage range and peak efficiency near full load.
• Soft switching was maintained across the entire operating range.

Conclusions:

• The novel analytical approach offers an efficient and systematic method for designing LLC resonant converters for wide voltage applications.
• This strategy enhances full-load efficiency and maintains soft switching.
• The derived equations facilitate design trade-off analysis, simplifying the optimization process.