Quasi Proportional Resonant Controller Based MMC Grid Side Harmonic Suppression Research

High-voltage direct current transmission based on modular multi-level converter (MMC-HVDC) has developed rapidly in recent years due to its advantages such as high efficiency, small size, no commutation failure, and the ability to supply power to passive AC systems. It has become a hot spot in the field of high-voltage direct current transmission. Many highvoltage direct current transmission projects based on modular multi-level converter have been successively built and put into operation all over the world. However, there are also some problems to be solved in MMC-HVDC project. For example, the high harmonic content at the network side of the converter leads to the serious voltage distortion at the common connection point (PCC), which leads to the maloperation of the protection of modular multi-level converter (MMC). The problem of harmonic pollution at the network side of the modular multi-level converter has affected the safe and stable operation of the MMCHVDC project. However, there is less analysis on this problem in the existing literature, so it is very necessary to further study this problem. Aiming at the problem of harmonic suppression on the network side of modular multi-level converter, a harmonic suppression strategy based on quasi proportional resonance controller (QPR) is proposed in this paper. The principle of this strategy is simple and easy to implement. The proposed harmonic suppression strategy has a certain reference value for solving the related problems in the actual MMC-HVDC project. The harmonic suppression strategy is simulated in PSCAD, and the simulation results show that the proposed harmonic suppression strategy has good harmonic suppression effect.