基于可变频率变压器的变速变频近海风电系统控制研究

项目名称： 基于可变频率变压器的变速变频近海风电系统控制研究

项目编号： No.51307025

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 电工技术

项目作者： 陈思哲

作者单位： 广东工业大学

项目金额： 25万元

中文摘要： 课题提出基于可变频率变压器(VFT)的变速变频近海风电系统，在海上采用笼型风电机组以降低故障率，通过VFT控制风电机群变速发电以提高风能利用率。该系统可靠性高，可减少风电机组的海上维护和停机损失，提高近海风电场经济效益。课题将研究其控制方法：①针对系统复杂的机电耦合关系，采用多时间尺度方法建立机械、电气子系统模型，在此基础上研究有功、无功功率控制方法；②研究基于非线性内点法的变速风电机群最大功率控制方法，根据风速分布实时计算变频交流母线频率和全体风力机桨距角的全局最优解，通过VFT和变桨距机构的协调控制减少风速不均匀分布导致的风能损失；③研究风电系统的低电压穿越控制方法，在电压跌落期间，通过对变频交流母线频率和风力机桨距角的协调控制，将所有笼型风电机组的转差率、转速控制在允许范围，避免风力机转速和端电压失稳，通过变流器向电网输出无功功率。课题研究成果将为近海风电开发提供一种经济可靠的方案。

中文关键词： 风力发电；可变频率变压器；笼型异步发电机；最大风能控制；低电压穿越

英文摘要： A variable speed variable frequency offshore wind energy conversion system (WECS) based on variable frequency transformer (VFT) is proposed in this project. Wind turbines based on squirrel-cage induction generators are used on the sea to reduce failure rates. The variable speed generations of wind turbines are enabled by a VFT, and hence the wind energy efficiency can be increased. The high reliability of the WECS will reduce the offshore maintenances and downtime of wind turbines, which will improve the economic benefits of offshore wind farms. The control methods of the proposed WECS will be studied in this project. ① Considering the complex electromechanical coupling relationships in the proposed WECS, the multi-time-scale method is used to establish models of mechanical and electrical subsystems, based on which the active and reactive power control schemes will be studied. ② A maximum power control method for a cluster of variable speed wind turbines will be studied based on nonlinear interior point algorithm, in which the global optimal solutions about the frequency of variable frequency AC-bus and pitch angles of all wind turbines will be real-time calculated according to wind speed distributions. Hence, the wind energy losses due to uneven distribution of wind speeds can be reduced by the coordinating con

英文关键词： Wind power generation；Variable frequency transformer；Squirrel-cage induction generator；Maximum wind power control；Low voltage ride-through