Thyristor controlled rectifier inverting at unity power factor

Conventionally, variable voltage dc power is converted to three phase 60 Hertz with three phase controlled rectifier operating in the inverting region and the input power factor varies with the magnitude of the dc voltage. This paper describes a modified controlled rectifier system which maintains the line power factor to almost unity independent of the magnitude of the dc voltage. Both conventional and modified schemes are analyzed and the expressions for power factor are derived. Also the above circuits are compared for slip energy recovery in one and two quadrant wound rotor slip energy recovery systems.