Three-Level TAIPEI Rectifier-Analysis of Operation, Design Considerations, and Performance Evaluation

A new low-cost three-phase four-switch three-level zero-voltage-switching (ZVS) discontinuous-current-mode power-factor-correction boost rectifier, for short named the three-level TAIPEI rectifier, that achieves a low input-current total harmonic distortion (THD) and features ZVS of all the switches is introduced. Since in the proposed rectifier the voltage stress of the four switches is equal to one-half of the output voltage, the rectifier can utilize switches with a lower voltage rating that, generally, have lower conduction losses. To reduce the switching-frequency range and maximize the light-load efficiency, the control is implemented by a combination of variable-switching frequency and phase-shift pulse-width modulation control. Detailed design guidelines for and performance evaluation of a three-phase 6-kW prototype designed for the line-to-line voltage range from 340 VRMS to 520 VRMS are presented. The prototype rectifier exhibits efficiency in the 96%-98% range and achieves less than 5% input-current THD over the entire nominal input-voltage range (380-480 VL-L, RMS) and above 50% of full load.