Isolated AC-DC Converter Research Articles

High Efficiency Isolated AC-DC Converter with Gradationally Controlled Voltage Inverter for On-Board Charger

We have developed a new isolated AC/DC converter for electric vehicle on-board chargers. It consists of an AC/DC converter with Gradationally Controlled Voltage Inverter (GCVI AC/DC converter) and an isolated Zero-Voltage-Switching (ZVS) DC/DC converter, each of which is optimally controlled to convert in a highly efficient means. As a result, the new on-board charger has achieved a power conversion efficiency of over 94%.

A high-power-factor, three-phase isolated AC-DC converter using high-frequency current injection

A single-stage, three-phase AC-to-DC converter topology is proposed for high-frequency power supply applications. The principal features of the circuit include continuous current operation of the three AC input inductors, inherent shaping of the input currents, resulting in high power factor, a transformer isolated output, and only two active devices are required, both soft-switched. Resonant conversion techniques are used, and a high power factor is achieved by injecting high-frequency currents into the three-phase rectifier, producing a high frequency modulation of the rectifier input voltages. The current injection principle is explained and the system operation is confirmed by a combination of simulation and experimental results.