High-Efficiency Discontinuous Current-Mode Power Factor Correction-Based Plug-In Battery Charger for Local e-Transportation

This article presents a high-efficiency dual sensor-based two-stage battery charger for low-voltage battery packs. The charger utilizes a discontinuous current-mode (DCM)-based front-end ac-dc interleaved buck-boost converter for active power factor correction (PFC) and an unregulated LLC converter with synchronous rectification (SR) for achieving high efficiency. Only two sensors are utilized for implementing converter charge control, thus increasing converter reliability and robustness. A detailed loss analysis is done in order to estimate an optimal dc-link voltage for high performance along with small-signal modeling for closed-loop control. Experimental results from a proof-of-concept 1.0-kW hardware prototype are demonstrated in order to verify the converter feasibility. An input power factor of 0.99, an input current total harmonic distortion of 3.85%, and a high efficiency of 96.06% are achieved from the prototype.