Direct power control for Universal Power Flow Controller series converter

To maximize the power flow in a transmission grid while maintaining stability, unnatural power flows can be enforced by a Unified Power Flow Controller. Theoretically the control of active and reactive power flow can be without overshoot or cross coupling. Direct power control, based on instantaneous power theory, can apply the full potential of the power converter and achieve better results. Simulation is performed on a full 3 phase model with non-ideal transformers, series multilevel converter and load. Experiments on a 3 phase scaled model with multilevel converter are performed. Simulation results are confirmed by experimental results and demonstrate minimum control delay, no overshoot and no cross coupling. Direct power control is a valuable control technique for a UPFC, and the presented controller can be applied to voltage source converters. In this paper, the Direct Power Control is demonstrated in detail for a 3 level Neutral Point clamped inverter.