Asymmetrical Fault Current Calculation Method and Coupling Effect Analysis in N-Paralleled Droop-Controlled Inverters

摘要

This paper investigates the current coupling characteristics of N-paralleled grid-connected inverters, which affects the design and operation of inverter, and makes fault current more complex and difficult to analyze. In this paper, by establishing the fault models of paralleled droop-controlled inverter, an asymmetrical fault current calculation method for N-paralleled droop-controlled inverter is proposed. On this basis, influence of main factors, including controller parameters, reference power and inverter line impedance, on fault current coupling degree are analyzed quantitively. Simulation results and calculation results verify the practical of the proposed calculation method and the correctness of theoretical analysis of coupling effect.