Adaptive decoupled power control method for inverter connected DG

Abstract

The integration of renewable energy technology is making the power distribution system more flexible, but also introducing challenges for traditional technology. With the nature of intermittent and less inertial, renewable energy-based generations need effective control methods to cooperate with other devices, such as storage, loads and the utility grid. The widely used power frequency (P-f) droop control is based on the precondition of inductive line impedance, but the low-voltage system is mainly resistive, and also the different load character needs to be considered. This study presents an adaptive droop control method based on online evaluation of power decouple matrix for inverter connected distributed generations in distribution system. Traditional decoupled power control is simply based on line impedance parameter, but the load characteristics also cause the power coupling, and alter the equivalent system impedance characteristic. In this study, the decoupled matrix is evaluated by the ratio of the variations of active power and reactive power under a small perturbation on the voltage magnitude. As analysed, the proposed decoupled control method can take the effects both the transmission line and the load characteristics into account, and it will be more practical, and flexible in various network and load conditions. The performance has been validated by simulation and experimental results. © The Institution of Engineering and Technology 2014.