Stability Analysis of Power Hardware-in-the-Loop Architecture With Solar Inverter

Power hardware-in-the-loop (PHIL) simulations have been rapidly growing in recent times due to the flexibility it offers in conducting various system-level studies as well as individual device evaluation. Evaluating a power converter has been one of the major applications of PHIL at recent times in the industry. Following this trend, this article proposes a way to evaluate a photovoltaic (PV) microinverter in PHIL arrangement. The mathematical background to quantify the stability criteria for a PHIL network is presented along with theoretical and experimental verifications. The methodology in this article is based on the model of interface devices and accurate delay model to analyze the stability of a PHIL system employing Routh-Hurwitz's formulation. An extensive analysis on stability along with the compensator design to enhance the stability limit of a PHIL system is presented. The workflow developed is applied to evaluate a 250-W PV microinverter, which showed a stable performance with more than 97% efficiency during steady state and transients.