An adaptive power compensation strategy for the voltage stabilization of LCL-VSC based microgrids

In this paper, an adaptive power compensation strategy for the voltage stabilization of LCL-VSC based microgrids is proposed. In this novel method, the load reactive power fluctuation and the reactive power consumption of the microsource output impedances are compensated in real time to adjust the reactive power reference in the droop parameters. First, the voltage and current double closed-loop control system on synchronous rotating frame of the LCL-based microsource inverter is decoupling designed and analyzed systematically. On this basis, the effects of two different feedback voltages on the inverter are studied for the purpose of optimizing the system static and dynamic features of the microsource. Next, via the mathematically modeling of the virtual impedance based droop controller adopted in the microsource, the basic principle of this proposed voltage stabilization method is analyzed in detail. Finally, a simulation experiment is implemented to validate the effectiveness of this new voltage stabilization strategy. The simulation results show that, the two-stage voltage fluctuations caused by the load and the output impedance can be suppressed effectively, and moreover, the smooth transition of the voltage magnitude can be achieved when the microgrids is incorporated into the power networks.