Sub-Modules Connected Modular Bidirectional Dual Active Bridge DC/DC Converter for Multi-Terminal VSC-HVDC Networks

This paper presents a sub-module connected single phase modular connected bidirectional dual active bridge (DAB) converter as an alternative to standard single module converters for multiterminal high voltage direct current (HVDC) systems. The modular DAB converter aims to meet the high voltage and current requirements of HVDC networks while ensuring stable operation under mismatches and faults. The sub-modules are controlled by a triple phase shift based neural network power sharing controller that has embedded fault detection and management capabilities. Using Matlab/Simulink, detailed partial and full power flow analysis are performed to demonstrate the stable operation of the DAB modules in both power flow directions when parametric mismatches are present. Additionally, the fault protection, detection, and reconfiguration capabilities of the modular converter are analyzed for DC faults. The converter topology is shown to satisfy the requirements for stable operation without negatively impacting the efficiency of the HVDC grid.