A flexible control strategy for integration of DG sources into the power grid

This paper deals with a multi-objective control strategy for integration of distributed generation (DG) sources to the power grid. The proposed control technique can provide simultaneous compensation for active and reactive power, and harmonic current components of loads through integration of DG sources to the grid, which is the main contribution of this work over the other proposed methods. A dynamic model of the proposed DG model is first formulated in the stationary reference frame and then transformed into the synchronous orthogonal reference frame. The transformed variables are used in control of voltage source converter (VSC) as the heart of an interfacing system between DG sources and utility grid. By setting appropriate reference currents in the control loop of DG, the maximum available power of DG source will be injected to the grid with fast dynamic response, thereby achieving sinusoidal grid currents in phase with load voltages, while the required power of the load is more than the maximum injected power of DG to the grid. The effectiveness of the proposed control strategy is validated with injection of maximum available power from the DG source to the grid, increased power factor of the utility grid and reduced total harmonic distortion (THD) of grid current through simulation results under dynamic and steady-state operating conditions.