Modeling and Analysis of HVDC Converter by Three-Phase Dynamic Phasor

A three-phase dynamic phasor (TPDP) model of high-voltage direct current (HVDC) systems, especially the converter, is proposed. The proposed model can rapidly solve the dynamic characteristics of the converter for symmetrical and asymmetrical operating conditions: 1) the symmetrical faults occur at the ac side or the dc side and 2) the asymmetrical faults occur at the ac side of the converter. Switch functions are used to indicate the commutation process of the converter. By using the sequence component method, it is observed that the vd should contain the 0th and 2nd components and i_a,i_b,i_c should contain the 1st and 3rd components. The TPDP model of the HVDC converter is proposed based on these observations. The interface and the details to establish the proposed model are presented and a method to represent the commutation failure in the TPDP model is also proposed. Simulation results show that the proposed model is effective and acceptable.