Conceptualization of a DC-LVRT for PEM Electrolyzers: Experimental Validation of a Noninverting Buck–Boost Converter With Feedforward Mode-Transition Compensator

Abstract

This article introduces and validates the concept of DC low-voltage ride-through (DC-LVRT) for critical DC loads through the utilization of a noninverting buck–boost converter (NIBBC), acting as a front-end converter in the DC power chain for powering polymer electrolyte membrane hydrogen electrolyzers. The objective of the control strategy for the NIBBC is to maintain a stable DC bus output even during severe input voltage disturbances, preventing protective shutdowns. The control scheme employs dual voltage-loop and single current-loop PI controllers, and a new feedforward mode-transition compensator designed to inject precise and fast duty support during sudden input voltage drops. A system-oriented model of the front-end and downstream conversion stages is developed as an equivalent load impedance for the controller design. An extensive stability and robustness analysis of the proposed strategy is presented and experimentally validated on a silicon-carbide-based prototype. The system was subjected to three disturbance profiles, operating the NIBBC in buck, buck–boost, and buck–boost marginal modes. Experimental results demonstrate that the control system maintains the output voltage within 20% of its 100-V reference, with recovery within 40 ms for all cases. The feedforward controller reduces voltage dips by up to 18%. A detailed hardware versus simulation analysis quantifies the impact of real-world imperfections on control performance, underscoring the importance of such considerations for reliable DC-LVRT implementation.