Active and reactive power control schemes for distributed generation systems under voltage dips

During voltage dips continuous power delivery from distributed generation systems to the grid is desirable for the purpose of grid support. In order to facilitate the control of distributed generation systems adapted to the expected change of grid requirements, generalized power control schemes based on symmetric-sequence components are proposed in this paper for inverter-based distributed generation, aiming at manipulating the delivered instantaneous power under voltage dips. It is shown that active power and reactive power can be independently controlled with two individually adaptable parameters. By changing these parameters, the relative amplitudes of oscillating power can be smoothly regulated, as well as the peak values of three-phase grid currents. As a result, the power control of grid-side inverters becomes quite flexible. Furthermore, two strategies for simultaneous active and reactive power control are proposed that preserves adaptive controllability. Finally, the proposed schemes are verified experimentally.