Power Flow Control of a Distributed Generation Unit in Micro-grid

Distributed generation units in micro-grid can be connected to utility grid as alternative energy sources besides providing power to their local loads. The distributed generation units are interfaced with utility grid using inverter. With inverter control, both active and reactive power pumped into the utility grid from the distributed generation units can be controlled. Reactive power flow control allows the distributed generation units to be used as static var compensation units besides energy sources. This paper has presented a power flow control approach for a DC unit in micro-grid. The proposed approach achieves decoupled P and Q control under grid-connected mode, an integral approach to conduct the power flow control has been developed to control P by adjusting the power angle and control Q by adjusting the filter capacitor voltage. This paper has described control system algorithm for the proposed power controller. Simulation and experiment results have demonstrated strong P and Q regulation capability, fast enough response, and purely sinusoidal line current.