Research On Complex Vector Control Strategy Of Direct-Drive Wind Turbine Converter

Vigorous development of renewable energy is an important measure to achieve the goal of "double carbon",wind energy as a renewable energy,because of the abundant reserves,clean and environmentally friendly,easy to develop and other advantages have become the main force of China’s energy transformation.At present,China’s offshore wind power is in a period of vigorous development,offshore wind power mostly uses direct-drive wind turbines,as the power conversion system converter is the key to achieve motor control and energy conversion.However,in the synchronous rotating coordinate system,there are cross-coupling components in the current loop of the converter,and feedforward compensation is usually used to decouple the coupling components,but feedforward compensation decoupling relies on precise system parameters,and when the environmental changes lead to system parameter uptake,incomplete decoupling occurs,which leads to system degradation.To this end,this paper focuses on the decoupling control of direct-drive wind turbine converters,and the main contents are as follows.Firstly,the mathematical model of wind turbine is established,based on which,the complex vector model of direct-drive wind turbine converter is established based on the AC motor complex vector theory.Secondly,the influence of the cross-coupling component of d-q axis on the dynamic performance of the current loop when the converter is not decoupled in the synchronous rotating coordinate system is studied,and the decoupling performance of the traditional feedforward decoupling control strategy is analyzed.The theoretical analysis of the decoupling ability and parameter robustness of the two control strategies is carried out,and the theoretical analysis is verified by simulation.Finally,the complex vector decoupling control strategy is applied to the current loop control system design of the direct-drive wind turbine converter,and the d-axis current complex vector control strategy of the machine side converter and the grid side converter grid voltage directional complex vector control strategy are designed.