A pulse width modulated AC link unified power flow controller

This paper proposes a new FACTS device: the Γ-controller. Based on the vector switching converters, the Γ-controller offers functional capabilities similar to the unified power flow controller, in the sense that it can independently control the active and reactive power flow through a transmission line. The control function, however, is realized by direct AC/AC conversion without frequency change, adopting the strategy of pulse width modulation. Operating principles, equivalent circuits, and design considerations are discussed. A detailed computer simulation is used to validate the approach.