Interconnection between different DC technologies at multi-terminal HVDC network

Abstract

The interconnection between line commutated converter (LCC) and voltage source converter (VSC) at multiterminal HVDC network introduces a challenge especially during power reversal operation. LCC changes the direction of voltage and keeps the current at the same direction, however VSC changes the direction of current and keeps the voltage at the same polarity. In this paper, a control system for LCC and VSC integration is presented. Bidirectional DC/DC converter is proposed to connect LCC and VSC HVDC systems in normal and power reversal conditions. DC/DC Converter structure and controls are presented including the converter connection. MATLAB/SIMULINK simulations are carried out to verify proposed system performance converter operation in different conditions.