Abstract – The paper talks the effects of synchronverter on a wind farm in a MMC-based HVDC system

Abstract – The paper talks the effects of synchronverter on a wind farm in a MMC-based HVDC system. A synchronverter is an inverter. The control of the wind farm connected to the power systems is done using synchronverter. It operates the same way as synchronous generators. The stability of an offshore wind power network connected through a high-voltage dc (HVDC) transmission line can be challenging since a strong ac collection (ACC) bus might not be available, when there is no rotating machine connected in that bus. Resonances or instability phenomena have been reported in between wind farms and MMC-HVDC systems. They are arguably originated due to interactions between the MMC and the wind power inverters. In addition, the synchronization unit (phase-locked loop, PLL) has shown to have a significant impact in achieving satisfactory performance. To tackle this problem, this paper has proposed a wind energy conversion system (WECS) controller for such an ACC bus based on the synchronverter concept. The dedicated synchronizing unit is been replaced by the self-synchronizing synchronverter. It synchronizes itself with the grid before and after the connection and adjust to the grid frequency. This considerably improves the performance, reduces the complexity, and computational burden of the controller.