变速恒频双馈风力发电系统励磁控制研究

【作者】 黄正；

【导师】 年晓红；

【作者基本信息】 中南大学 ， 控制科学与工程， 2010， 硕士

【摘要】 能源、环境是当今人类生存和发展所要解决的紧迫问题,风能作为一种清洁的可再生能源,已经受到世界各国的高度重视。而随着风力发电机组容量的不断增大,提高运行效率、最大程度利用风能已经成为风力发电技术的研究热点。面对更多采用双馈型异步发电机(DFIG)的风力发电系统,对其控制策略的研究以及如何进一步提高系统稳定性和动态运行能力具有重要的意义。矢量控制以其优良的动静态性能、高品质的精度控制、成熟的工业应用成为电机控制领域的主流技术。但是它的缺点是需要进行反复的坐标变换,控制系统复杂。直接功率控制(DPC)策略是在直接转矩控制(DTC)基础上发展而来的,具有结构简单,动态响应快速,参数的鲁棒性能好等特点。但是传统的DPC策略具有开关频率不能恒定,输出电流谐波大,启动时直流电压、有功无功功率波动大,控制精度不高等缺点。针对直接功率控制的特点,提出了两种改进的控制策略：基于模糊PI控制的直接功率控制策略和基于空间矢量调制(SVM)的直接功率控制策略。针对传统PI控制器的弱点,提出的一种模糊PI控制器,并成功应用于直接功率控制策略的直流环节中。仿真结果表明该策略有效地减小了传统DPC策略启动过程中直流电压、有功和无功功率的波动。基于SVM的直接功率控制策略是在传统DPC策略中引入了SVM,同时针对直接功率控制输出电流谐波大、无功功率出现小范围的失控的缺点,提出了一种构造电压空间矢量的新方法。仿真结果表明了该策略能够使开关频率恒定,同时有效减小了无功功率失控的区域,减小了输出电流谐波。更多还原

【Abstract】 Energy and environment are the urgent problems that human beings exist and development nowadays.Wind power has attacted more and more highly attention as one kind of clean regenerative energy sources. With the wind generator capacity increasing, How to improve th operation efficiency and maximum use the wind power has become a hotspot. More and more doubly-fed induction generator (DFIG) of wind power system has been used, the research on its control strategy and how to further improve the system stability and dynamic operation ability has a vital significance.Consider of the excellent static and dynamic performance, high-quality precision of control, matrue for industrial areas. But it has some weakness like that it must need repeated coordinate transformation and the control system has complicated structure.Direct Powe Control (DPC) strategy is based on in direct torque control (DTC), It’s characteristic is that the simple structure, fast dynamic response and robust performance of the parameters is good. But it’s has some obvious weakness in traditional DPC strategy,such as the switch frequency not constant, output current has a little harmonics, the fluctuation of direct voltage and active power and reactive power when the system strats., control accuracy is not high.The paper puts forward two improved strategies aimed at the characteristics of the DPC strategy:DPC strategy based on fuzzy PI controller and DPC strategy based on Space Vector Modulation (SVM). A fuzzy PI controller is proposed and successfully applied in DPC strategy which is the core content of the DPC strategy based on fuzzy PI controller. Simulation results show that the strategy could effectively reduce the fluctuation of the direct volage,active power and reactive power when the system strats. DPC strategy based on SVM introduced SVM in traditional DPC strategy and proposed a new construction method of voltage space vector which aimed at the DPC strategy weakness that output current has a little harmonics, reactive power out of control in small areas. Simulation results show that the strategy could make the switching frequency constant, effectively reduce the area of reactive power out of control and reduce the output current harmonics.更多还原