Abstract
This paper presents a DC-link voltage controller for fulfilling the post-fault active power recovery requirements imposed to inverter-based resources (IBRs) by modern grid codes such as IEEE 2800. The proposed controller is designed for gridfollowing IBRs and avoids windup during severe transients by applying a backtracking mechanism with two separate feedback loops to a regular Proportional-Integral (PI) DC-link voltage controller. One of the backtracking loops is operating on the current reference saturation, while the other operates on an adjustable power ramp-rate limiter placed at the output of the PI controller. This ensures robust and stable operation without controller windup during the low voltage ride-through (LVRT) process caused by short-circuit faults, and a controlled recovery after the fault. The tuning of the PI controller parameters and backtracking gains is evaluated under grid fault conditions by detailed simulations conducted in an electromagnetic transient (EMT) environment. Comparisons with conventional control methods validate the superior performance of the proposed DClink voltage controller design in response to LVRT sequences with controlled post-fault power ramping requirements.