Hardware-in-the-Loop Methods for Stability Analysis of Multiple Parallel Inverters in Three-Phase AC Systems

Modern electric distribution systems typically contain several feedback-controlled parallel inverters that together form a complex power system. Consequently, number of issues related to stability arise due interactions among multiple inverter subsystems. Recent studies have presented methods where the and other dynamic characteristics paralleled system can be effectively analyzed using impedance measurements. This article presents implementation techniques for comprehensive online analysis grid-connected hardware-in-the-loop measurements based on an OPAL-RT real-time simulator. The is simultaneous current control loop gains grid impedance, aggregated terminal admittance inverters. includes measurement inverters’ output gains, global minor gain, impedance. make it possible rapidly evaluate both local levels in real time, thereby providing means monitoring or adaptive such systems. Experimental are shown from high-power energy recently developed at DNV GL, Arnhem, Netherlands.