Voltage and frequency control of inverters connected in parallel forming a micro-grid

The “communication mechanism” to realize the power share of grid-forming inverters is analyzed and a droop control method through active and reactive current is proposed in this paper. The control strategies of inverters connected in parallel forming a micro-grid are described in detail. The droop controller is divided into three units that are current (power) decoupling, the first-order inertia and droop control. From the point of synchronous generator, the design principles of first-order inertia constant and the droop coefficients are analyzed. Finally, simulation models are established in Simulink/Matlab and two prototypes with the capacity of 10kVA are established in laboratory. The simulation and experiment results verify the feasibility of the proposed method.

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