A Finite-time Distributed Cooperative Control Approach for Microgrids

Reactive power sharing cannot be achieved using many existing microgrid (MG) control methods, but the convergence speed of these methods is slow. To solve these problems, a finite-time distributed control approach is proposed in this paper, which is based on the hierarchical control structure. The hierarchical control structure consists of a dual loop control, a droop control used as a primary control and a secondary control. First, the secondary controller is modeled, and the MG system composed of distributed generators (DGs) is considered as a multi-agent system. The secondary controller consists of a frequency regulator, voltage regulator and power regulator. Secondly, the adaptive virtual impedance module is established, using the output of the reactive power regulator as its input. Thirdly, a dual loop controller is combined with a primary controller and secondary controller to generate a pulse width modulation (PWM) signal to control the power and voltage of the MG. In order to reduce the fluctuation of the MG, a damping module is introduced when the structure of the system changes. Finally, the stability of the proposed control strategy is proved by the related theorems. A simulation system is established in the Matlab environment, and the simulation results show that the proposed method is effective.