THREE PHASE BOOST CONVERTER TO ACHIEVE UNITY POWER FACTOR AND LOW INPUT CURRENT HARMONICS FOR USE WITH AC TO DC RECTIFIERS

摘要

A voltage source inverter comprises a zigzag transformer providing a neutral point. A rectifier unit comprises three single phase boost converters each connected to one of the three phases of AC power and the neutral point and comprising a bridge rectifier converting single phase AC power to DC power and using a boost inductor with a boost switch and blocking diode to develop a DC output. An inverter receives DC power and converts DC power to AC power. A link circuit is connected between each boost converter DC output and the inverter circuit and comprises a DC bus having first and second rails to provide a relatively fixed DC voltage for the inverter and a DC bus capacitance across the first and second rails to smooth voltage ripple. A switch controller controls operation of the boost switches using average current control for each of the boost converters.