Operating region in active-front-end voltage/current source rectifiers

Commercial active-front-rectifiers based upon three-phase voltage source topologies are capable of both supplying or absorbing reactive power from the electrical distribution system while serving as high DC power supplies. This is an important feature in industrial facilities where high power factor operation is of concern. This paper shows that the available range of reactive power in such topologies depends upon the actual active power being supplied by the topology to the load. Moreover, both the voltage and current source based topologies have limited and variable maximum reactive power compensation capabilities. In fact, both topologies are capable of providing maximum reactive power compensation when supplying 0.707 pu active power when operating passive loads in the rectifier mode. Extended analysis shows that during regeneration both topologies are also capable of supplying or absorbing limited amounts of reactive power from the electrical distribution system. Simulated and experimental results confirm the theoretical considerations.