Small-Signal Modeling of Grid-Forming Power Converter

Grid-forming converters have been proved to be important assets in modern power systems where the net inertia is decreasing significantly due to the replacement of conventional synchronous generators. Yet, models of grid-forming converters are still at best scarce. This paper presents a modelling approach to derive a small-signal representation of a synchronous power converter-based grid-forming power converter. The small-signal models take into account control dynamics of all the control layers such as the current controller and power controller. From the derived model, eigenvalue analyses are carried out to propose reduced models with different levels of computation complexity to meet the requirement of the applications. The proposed approach is validated through simulations under various conditions.