Wide-Input Series Half-Bridge LLC Resonant Converter and Its Control Strategy

• • The series half-bridge LLC converter clamps switch voltage stress to Vin/2, enabling 100-400 V input operation with 600 W full-load output; this directly reduces semiconductor voltage ratings and conduction losses in photovoltaic and EV charging front-ends where input varies by 4:1. • • Frequency doubling in low-gain mode halves the switch operating frequency while maintaining identical resonant network input voltage vAB frequency, keeping the resonant tank frequency range narrow across the entire input span; this simplifies magnetic design and reduces core losses compared to conventional wide-range PFM. • • The PSM-PWM-PFM hybrid control achieves stable mode transitions between HG and LG modes at the threshold Vin,th, preventing output voltage overshoot or oscillation during input voltage transients; this is critical for grid-tied renewable systems where source voltage fluctuates rapidly. • • The PSM-PWM hybrid voltage-balancing control corrects input capacitor voltage imbalance without additional hardware, maintaining voltage sharing across C1 and C2 under asymmetric load or component tolerance; this ensures reliable switch voltage clamping and extends capacitor lifetime in field deployments.