LLC converter

An LLC converter is a resonant DC-DC converter known for its high efficiency, soft switching (zero-voltage switching, ZVS)

What is an LLC Converter?

LLC stands for:

• L – Resonant inductor
• L – Transformer leakage inductance
• C – Resonant capacitor

Together, they form a series or series-parallel resonant tank, which shapes the switching behavior.🔁 Basic Operating Principle

• Converts DC input to high-frequency AC using a full-bridge or half-bridge inverter
• Resonant tank (LLC) filters and transfers energy efficiently at resonance
• Output is rectified and filtered back to DC

Frequency Control (Typical Method)

• Regulate output by changing switching frequency (not duty cycle)
• At resonance: high efficiency
• Below resonance: capacitive region (ZVS)
• Above resonance: inductive region (ZCS)

🧰 Simulink Implementation of LLC Converter

Key blocks in Simscape (Electrical):

• Controlled Voltage Source / PWM Generator
• MOSFET or Ideal Switch
• Resonant tank components (L and C)
• Transformer with leakage inductance
• Full-wave or synchronous rectifier
• Output capacitor and load
• Voltage feedback and controller (PI for frequency modulation)

📈 What to Monitor in Simulation

• Output voltage regulation vs. input variation
• Switching waveforms (voltage and current across MOSFETs)
• ZVS operation (voltage drops to 0 before switching)
• Efficiency and thermal performance (if modeled)