Robust Control of PMSG-based Wind Turbine under Grid Fault Conditions

This paper presents modeling of a direct-driven permanent magnet synchronous generator – based wind turbine and proposes a new controller for Back-To-Back (BTB) converters to enhance Low Voltage Ride Through (LVRT). The LVRT is implemented without any additional devices during grid fault conditions. In this structure, the Proportional-Integral (PI) controllers of Machine Side Converter (MSC) and Grid Side Converter (GSC) are replaced by Sliding Mode (SM) controllers. The MSC controls dc-link voltage and the GSC controls Maximum Power Point Tracking (MPPT) by regulating turbine-generator speed. This control strategy implements different grid code requirements such as Danish grid code. The proposed SM controller in comparison with the PI controller can eliminate dc-link voltage oscillations and reduce the converter voltage and current stresses. Simulation results verify the robustness and effectiveness of the proposed strategy. Hence, by using SM controller, there is no need for additional equipments to enhance LVRT in PMSG-based wind turbines and cost and complexity are significantly reduced.