Black-Start Power Capacity Sizing and Control Strategy for an Islanded DFIG Wind-to-Hydrogen System

TL;DR

This paper presents a novel black-start method for an off-grid wind-to-hydrogen system using DFIG wind turbines and PEMFCs, with a focus on capacity sizing and coordinated control to ensure stable startup and operation.

Contribution

It introduces a new capacity sizing approach for PEMFCs and a comprehensive control strategy for stable black-start and operation of wind-to-hydrogen systems.

Findings

PEMFC capacity supports reliable black-start

Control strategy ensures smooth self-startup

System maintains stable voltage and frequency

Abstract

This paper proposes a black-start method for an off-grid wind-to-hydrogen (W2H) system comprising a wind farm based on Doubly-Fed Induction Generators (DFIGs), proton exchange membrane fuel cells (PEMFCs) serving as the black-start power source, and a hydrogen production industry. The PEMFC is installed within the hydrogen industry to facilitate direct access to hydrogen fuel. Based on the microgrid topology and black-start scheme, this study innovatively sizes the rated capacity of the PEMFC through power flow analysis. The capacity must be sufficient to charge passive components such as transmission lines and transformers, provide rotor excitation, and supply wind turbine (WT) and electrolyzer (ELZ) auxiliaries during startup. The proposed system integrates wind-hydrogen coordinated control (WHCC) and hydrogen-storage coordinated control (HSCC). Under maximum power point tracking (MPPT) of the WTs, the ELZ follows power fluctuations to absorb wind output, ensuring stable voltage and frequency. Fixed-frequency control applied to either the DFIG or PEMFC converters enables DFIGs to retain conventional grid-following (GFL) operation, reducing converter development costs. For both control modes, this paper establishes the black-start sequence and formulates a comprehensive coordinated control strategy for the entire system. The entire control system is validated through simulations in MATLAB/Simulink. Results confirm that the calculated PEMFC capacity supports reliable black-start, while the black-start control strategy ensures smooth system self-startup. Furthermore, the coordinated control strategy maintains stable frequency and voltage under fluctuating wind power, demonstrating the practicality and robustness of the proposed approach.