A Low Voltage Ride-through Theoretical Study Of Direct-drive Wind Turbine Based On TSMC

In the wind turbine system, the manner of direct drive permanent magnet synchronous generator without gear-box can effectively improve its efficiency and reliability, and the operation and maintenance costs decreases, Direct-drive system have a rapid expansion in the wind power market.Usually the Direct-drive permanent-magnet wind turbine system use a conventional back-to-back converter as it connects the generator to the external network. In this converter, the back-to-back converter's dual bridges have their own control independently by a large DC-bus capacitor, also the converter size and consume increased. At the same time, the sudden change of DC-link voltage will greatly reduce the lifetime of capacitor in case of grid failure especially in grid voltage dips or recovery process. Two-Stage Matrix Converter is a new kind of Matrix Converter in recent years, the topology has similitude with traditional AC-DC-AC converter, but it has no energy storage element in the DC link. They have a good input and output performance and the output power factor can be controlled, while avoided the conventional matrix converter complicated four-step commutation and simplified the modulation strategy. So it is suitable for direct-drive wind power system as the full power converter.The wind farms voltage drop is caused by a grid failure or disturbance, the wind turbine and network operation without interruption when voltage drop in a certain range, this process known as the wind turbine through the time of low voltage. In this paper, the technology of low voltage ride through by Direct-drive wind power system based on TSMC has researched. First analyzes working principle of Two-Stage Matrix Converter and established the mathematical model of grid-connected inverter of TSMC in different coordinate systems, proposed the grid-connected inverter of Two-Stage Matrix Converter as the system closed-loop control objects, proposed the integrated control strategy which is the best suited for low voltage ride through, at the same time provided reactive power to the grid by German E. ON company power grid reference standards and State Grid Corporation of wind power standards. The simulation analysis shows that, the Direct-drive wind power system based on TSMC has a better dynamic steady state performance, system can safely run in the voltage drop and the reactive power support to the grid. TSMC and the Direct-drive permanent magnet synchronous generator combination of the system have strongly advantages for development.