Resonant LLC converter based e-bike charger

Abstract

This thesis presents the development of a high-efficiency electric bicycle (e-bike) charger based on a two-stage power conversion architecture. The proposed charger integrates a Boost Power Factor Correction (PFC) converter with an LLC resonant DC-DC converter to address the challenges of power quality, efficiency, and compactness in modern electric mobility solutions. With the growing adoption of e-bikes as a sustainable mode of transportation, the need for chargers that comply with international harmonic and power factor standards has become increasingly important. The front-end PFC stage is designed to shape the input current waveform, reduce harmonic distortion, and enhance compatibility with grid infrastructure. Both continuous and critical conduction modes are explored to optimize performance under different load conditions. The second stage employs an LLC resonant converter, selected for its ability to achieve soft switching, notably Zero Voltage Switching (ZVS), thereby reducing switching losses and electromagnetic interference (EMI). A frequency modulation-based control strategy is adopted for regulating output voltage across a wide load range while maintaining efficient operation.