Research on the internal modal decouping control of VSC-MTDC

As a new type of HVDC technology based on voltage source converter, VSC-MTDC has many technical advantages and broad application prospects. The paper describes a mathematical model of VSC-HVDC system in dq synchronous rotating coordinate system, but the currents of active and reactive are coupling. Here, the use of internal control principle to achieve a decoupling of the current inner loop, independence control of active and reactive power, the inner current loop controller is designed and the basis of the controller parameter setting indicators is given. Moreover, the proposed strategy was simulated by MATLAB. The results show that the method can achieve decoupling control of active and reactive power and have good dynamic quality and robustness, which verify the correctness and validity of the control strategy in a three-terminal VSC-HVDC.