Efficiency-optimized Modulation Scheme of Active Soft-switching Cell for 1-ph/3-ph Universal Voltage Input PFC for On-Board Charger Applications

A detailed analysis and experimental evaluation of an optimized modulation scheme of a simple continuous-conduction-mode (CCM), pulse-width-modulated (PWM), boost-type active soft-switching cell suitable for 1-ph/3-ph universal voltage input on-board charging (OBC) applications is introduced. The soft-switching cell features zero-voltage switching (ZVS) of all switches and reduced reverse-recovery loss at any operating point as well as simple control. The cell achieves high efficiency for converting low line voltage to the high dc link voltage required for the OBC DC-DC converter. The concept was experimentally evaluated on a single-phase 3.4 kW prototype designed to operate at 220 V RMS line input and deliver 650 V output. The proposed modulation scheme reduces magnetic and conduction losses resulting in an increase of the power conversion efficiency by 0.250/0. The prototype achieves 98.0% efficiency at full load and 100 kHz switching frequency. The soft-switching PFC rectifier concept naturally morphs between an interleaved totem-pole converter for 1-ph ac line voltage and a 3-ph converter for 3-ph ac line voltage.