Fault Ride-through Capability Of The Induction Generator Wind Turbines With Full Rated Converter

In recent years, with the continuous development in power electronicstechnology and the continuous reduction in converter cost, the market share of thewind turbine with full rated converter continues to rising. Considering the rare earthprice and the unit bulk may restrict the Permanent Magnet Synchronous Generatorcapacity to further expand, this paper research on the Fully Rated ConverterInduction Generator (FRC-IG), especially on the fault ride through of the windturbine, main work done and results achieved shown as follows:(1) The dynamic model of the FRC-IG wind turbine is established firstly, inorder to analyze the wind turbine working principle and operational characteristics.Then, based on the full rated converter traditional control strategy, a new controlstrategy, which applies machine side converter to stabilize DC voltage, grid sideconverter to conduct maximum power tracking, is proposed.(2) The principles of the DC voltage fluctuations of the FRC-IG wind powersystem with the traditional control strategy are investigated. Then, several lowvoltage ride-through control strategies, which are applicable to the full ratedconverter wind turbine, are comparative analyzed from the perspective of powerbalance. In conclusion, the low voltage ride through control strategy based onenergy storage is superior to others in energy use and costs.(3) Several low voltage ride-through control methods of the FRC-IG windturbine based on electromechanical energy storage are proposed. Those methodscan regulate the output power of the wind turbine and eliminate the powerimbalance on both sides of the converter to stabilize the DC voltage throughadjusting the electromagnetic torques or switching the maximum power trackingcurve. Furthermore, a comprehensive control strategy, which adjusts the operative modes of the energy storage device and grid side converter, is also investigated.With the proposed control strategy, the wind power system can achieve smoothpower output and get strong low voltage ride through capability. The controlstrategy based on electromechanical energy storage is the best fault ride throughscheme because of requiring no additional hardware costs.(4) Based on the analysis of the grid side converter response during the gridvoltage surge, the high voltage ride-through operational characteristic of theFRC-IG wind turbine is discussed. Then, a high voltage ride-through controlstrategy, which combines crowbar circuit and the grid side converter reactiveoperation mode, is proposed.