Study on Stability of Hand-in-hand Structure of Multi-terminal DC Hydrogen Production System

Abstract

Multi-terminal DC (MTDC) hydrogen production systems are becoming one of the important forms of power distribution systems with the increasing growth of distributed renewable energy sources (such as PV and wind turbines), energy storage devices, and DC loads. To explore the key factors in stability analysis, the circuit diagram of MTDC hydrogen production system in hand-in-hand structure composed of voltage source converters (VSCs), DC lines, renewable energy and DC hydrogen production load was established in this paper. The overall state space model of the system was put forward, taking the master-slave converter control strategy into consideration. Then, the small-signal stability analysis of the MTDC hydrogen production system was carried out by comparing and analyzing the moving trajectories of the dominant eigenvalues in different system parameters. The key factor affecting the stability of the system such as DC capacitance of the converter and the electrolyzer power in the DC bus are determined. On this basis, a simulation model of the low-voltage MTDC hydrogen production system was built based on MATLAB/Simulink to verify the correctness of the theoretical analysis.