An adaptive switched capacitor strategy for efficiency optimization in LLC converters.

Area of Science:

• Electrical Engineering
• Power Electronics

Background:

• LLC resonant converters exhibit peak efficiency within narrow operating conditions.
• High voltage conversion ratios lead to increased switching frequency and reduced efficiency.

Purpose of the Study:

• To propose a novel adaptive switched capacitor control strategy for LLC resonant converters.
• To improve power conversion efficiency across a wide range of load conditions.

Main Methods:

• Developed a mathematical model linking power loss to resonant capacitance and load current.
• Implemented on-the-fly calculation of optimal resonant capacitance.
• Dynamically adjusted resonant capacitance using a switched capacitor bank.

Main Results:

• Mitigated switching frequency broadening.
• Achieved significant improvements in power conversion efficiency.
• Demonstrated efficiency increases of 3.6% (light load) and 3.9% (heavy load) in a 450 W converter.

Conclusions:

• The adaptive switched capacitor control strategy effectively enhances LLC resonant converter efficiency.
• Dynamic resonant capacitance optimization is key to improving performance under varying loads.