Co-ordinated Approach of Hybrid Adaptive Control on Wind Energy Integrated VSC-Multiterminal HVDC Grids

Despite of the distinctive feature of Multi-terminal HVDC (MTDC) network, a co-ordination between voltage source converters (VSCs) is essential on a wind farm (WF) integrated MTDC network. In this paper a hybrid adaptive control strategy is proposed on WF-VSC of the MTDC system considering wind farm as the weaker grid compared to AC grids. Firstly, a hybrid control is achieved by facilitating decoupled PQ control, dc link control and frequency regulation on WF side VSC, which operate in parallel. Then, the adaptive features are integrated on dc link and frequency regulation by an index matrix and ratio-based solution through adaptive droop. Furthermore, a co-ordination strategy is implemented between the adaptive controllers to redirect the power flow through AC and DC grids for improved power sharing. The effectiveness of the proposed control is tested on a four-terminal wind farm integrated MTDC network and modified IEEE-39 Bus system on PSCAD. The improvement is highlighted by comparing the proposed method with traditional decoupled-PQ control-fixed droop method under various scenarios.