Parameters design and optimization for droop-controlled inverters considering impedance characteristics and power stability

Abstract

The droop-controlled inverters (DCIs), which can simulate synchronous generators’ frequency and voltage behavior and provide active and reactive power support for the utility grid, are universally regarded as grid-friendly interfaces. This paper aims to give a general parameter design outline for the DCIs to simplify the complicated parameter tuning task while assuring good performances. For this purpose, the DCIs’ equivalent output impendence and admittance models are first developed, based on which the effects of parameters on impedance characteristics and power stability are analyzed in detail. Afterward, the general parameter design outline with a comprehending parameter tuning scheme is proposed based on the impedance analysis results. In the end, a 15-kVA prototype is established and tested in the laboratory. The experimental results verified the effectiveness of the proposed parameter design and optimization method.

Keywords

• Droop-controlled inverter
• Parameter design
• Impedance characteristic
• Power stability