Source Impact of a DC/AC Converter on Impedance-based Stability Analysis for Power Hardware-in-the-Loop Setups

Power Hardware-in-the-Loop (P-HIL) provides a controlled environment in a lab to test hardware under realistic operating conditions. Interfaces are implemented to connect the Hardware-of-Interest (HoI) and the digital real-time simulator (DRTS). Delays and noise are introduced through the DRTS and interfaces, which can cause inaccuracy and instability. Before conducting experiments, the stability of P-HIL with a chosen Hardware of Interest must be analyzed to prevent damage to the setup. This paper assesses the stability of a P-HIL setup using an impedance-based modeling approach when the HoI is a grid-following converter. It focuses on the DC port’s impact on the stability analysis, whereby the DC port is considered dynamic. To apply the impedance-based stability analysis, the grid and inverter impedances of this setup are modeled and calculated. Through frequency response, the calculated impedances are verified in simulations. The stability criteria for the P-HIL setup are verified by comparing the Nyquist criterion with the time domain response in Simulink/MATLAB.