LLC Resonant Converter using Pre-Charged Capacitor for High Input Voltage – High PAPR Envelope Tracking

摘要

This paper presents a single stage LLC resonant converter including a pre-charged capacitor (LLC-PC) for high input voltage, high peak-to-average power ratio (PAPR) envelope tracking (ET) application. It can achieve high efficiency and fast response speed simultaneously. Compared with conventional buck converter for ET, this converter adopts isolated LLC resonant topology to enable the use of high input DC voltage. While the main converter itself can regulate the output voltage to track average state voltage envelope, the pre-charged capacitor is used to respond to high dv/dt and peak state voltage envelope. GS66516B, 650 V Gallium Nitride enhancement mode high electron mobility transistors (GaN E-HEMT) are used as switching devices to decrease switching loss. A 400 V to 24 V (average)/48V (peak) 1 kW 500 kHz LLC-PC converter is designed and simulated using PSIM. Finally, preliminary experimental results from a scaled down laboratory prototype are presented for proof of concept.