MMC-HVDC Resonance Suppression Strategy based on Co-Optimization of Voltage Feedforward and Current Inner Loop

Aiming at the high-frequency resonance problem of High Voltage Direct Current Transmission based on modular multilevel converter(MMC-HVDC), this paper proposes a strategy based on voltage feedforward and current inner loop co-optimization. Firstly, the harmonic linearization method is used to build the sequential impedance model of the flexible DC converter, and the stability of the system is analyzed using the negative resistance effect. Then, different filtering links are strung into the voltage feedforward link and current inner loop of the flexible DC converter control circuit, which are used to improve the negative damping degree of the MMC converter. The optimal parameters for each filtering link are selected using the black-winged kite optimization algorithm(BKA) to maximize the positive damping band of the system. Finally, the simulation verification on PSCAD / EMTDC shows that the method can suppress the oscillation accident of the MMC-HVDC.