Three-Level Flying-Capacitor-Based 100 W USB-C PD GaN Charger in Aircraft Applications

This paper provides the operation principle and evaluation of a three-level flying-capacitor-based 100 W USB-C Power Delivery (PD) GaN charger in aircraft applications. A proportional resonant compensation combined with input voltage feedforward is analyzed to accommodate the high line frequency of the aircraft. A two-step soft startup process is proposed to avoid possible overvoltage of the switching devices. Thanks to the application of the 200 V GaN device by the three-level topology and continuous-conduction-mode (CCM) operation, the peak efficiency of PFC stage is 98.5%. The total harmonic distortion (THD) and EMI performance are evaluated with the experiment.