New Single-Switch Three-Phase High-Power-Factor Rectifiers Using Multiresonant Zero-Current Switching

A new family of single-switch three-phase highpower-factor rectifiers, which have continuous input and output currents, is introduced. By using a multiresonant scheme, the transistor operates with zero-current switching (ZCS), and the diodes operate with zero-voltage switching (ZVS). These multiresonant rectifiers with a single transistor are capable of drawing a higher quality input-current waveform at nearly unity power factor and lower stresses than quasi-resonant rectifiers. Buck-type converters are used for the power stage, and, hence, the output voltage is lower than the input voltage. Moreover, these rectifiers have a wide load range and low stresses on semiconductor devices. From the analysis, normalized characteristics of the rectifier are derived. The design and breadboard implementation of the rectifier delivering 147 Vdc at 6 kW from a 3 240-Vrms(LL) input is described. The total harmonic distortion (THD) of the line current is less than 5%, and the system efficiency is about 94% at the full load.