Wideband identification of impedance to improve accuracy and stability of power-hardware-in-the-loop simulations

Abstract

The Power Hardware in the Loop (PHiL) technique, critical for power systems where testing grid connected power converters may be difficult, allows connecting a real Device Under Test (DUT) with the real-time simulated Rest Of System (ROS) at power level. An Algorithm Interface (IA) and a power amplifier connect ROS and DUT. This paper presents the application of the Wideband System Identification (WSI) technique, an online method to measure impedance over a wide frequency range, combined with the Damping Impedance Method (DIM) IA, to improve both accuracy and stability of a PHiL test bench. First, the impedance of the DUT is identified via the WSI. Then, the DIM IA is updated with the measured wide frequency range impedance of the DUT. The application of the method is illustrated for the scenario of a PHiL test of a DC microgrid with a passive load.