Synchronous Machine Emulation of VSC for Interconnection of Renewable Energy Sources through HVDC Transmission

摘要

This paper develops a control strategy for a VSC– HVDC transmission system by referring to the synchronverter concept. In the proposed method, the sending-end rectifier controls emulate a SM, whereas the receiving end inverter emulates a SG to transmit power from one grid to another. The two converters connected by a DC line provide a Synchronverter HVDC (SHVDC) link. A windfarm with a type 4 permanent magnet SG is integrated into the HVDC link through a rectifier. Depending on the wind speed, the proposed control strategy automatically shares and manages the wind generator power on the DC side by using a BESS connected to the HVDC link to stabilize the power fluctuations generated by the intermittency of the wind farm. The performance of the synchronverter-based HVDC transmission was verified by using a MATLAB Simulink model. The controller effectively controls the power flow from one grid to another and that the effect of wind fluctuation on the grid can be mitigated with the BESS at the DC link. Therefore, by properly controlling the SHVDC, BESS, and RES connected to the HVDC system, the power from remote RES can be connected to a weak AC grid in a stable manner.