Fault ride-through capabilities are essential for grid-forming (GFM) inverters, particularly for providing ancillary services such as fault reactive current injection and phase jump active power delivery. Conventional GFM controllers, often based on cascaded voltage-current control structures, involve complex designs, require meticulous parameter tuning, and complicate analysis. To address these issues, we previously introduced a hybrid strategy that switches between GFM and current controllers. However, while this approach effectively limits current magnitude during grid disturbances, it fails to preserve the crucial voltage angle-forming characteristic adequately. This paper extends this hybrid strategy with a controller designed to maintain the voltage angle-forming characteristic while concurrently limiting the current magnitude. This integrated approach facilitates the independent design of the GFM and current controllers and ensures the delivery of ancillary services mandated by grid codes. Numerical simulations of a single-phase synchronous inverter during grid disturbances verify the effectiveness of the proposed controller.
Sekizaki et al. (Wed,) studied this question.