基于间接功率控制的无刷双馈风力发电机组多类型故障的无Crowbar低电压穿越方法

With the increasing failure rate of doubly-fed machine in megawatt of variable speed constant frequency wind power generation system, the brushless doubly-fed machine is highly anticipated. The brushless doubly-fed machine operates without brush and slip ring, it has simple structure and high reliability, the capacity of corresponding converter is small, which especially suitable for using as wind power generator. In recent years, the problem of efficiency of brushless doubly-fed machine which plagues the domestic and foreign scholars for a long time has made a significant breakthrough, and gradually shows broad application prospects in variable speed constant frequency wind power generation system. Focusing on the behavior characteristic of brushless doubly-fed wind power generator when grid symmetrical and asymmetrical voltage drop and the low voltage ride through control strategy, the concrete content of this project includes: 1. The brushless doubly-fed wind power generator fault transient characteristics analysis when grid symmetrical and asymmetrical voltage drop. 2. A flux tracking method of low voltage ride through of brushless doubly-fed wind power generator based on indirect power control strategy under the symmetry and asymmetry fault of the grid is proposed, which can control the flux of control winding tracking power winding flux during the fault to protect wind generating set. The advantage of this method is (1) The torque is low during low voltage ride through so as to reduce the impact the torsion shear of wind generating set; (2) It suitable for symmetric and asymmetric low voltage faults; (3) Without increasing the hardware. 3. The idle load grid-connection strategy of brushless doubly-fed wind power generator which based on indirect power control strategy is proposed to achieve the flexible grid-connection; the theoretical foundation is provided for practical engineering application of brushless doubly-fed wind power generator by this research.

随着兆瓦级变速恒频风力发电系统中有刷双馈发电机故障率的日益增多，人们对双馈电机的无刷化充满期待。无刷双馈电机无需电刷和滑环，结构简单，可靠性高，所需变频器容量小，特别适合作为风力发电机使用。近年来，长期困扰国内外学者的无刷双馈电机的效率问题取得重大突破，在变速恒频风力发电领域逐渐显现出广阔的应用前景。本项目围绕无刷双馈风力发电机电网电压跌落故障下的行为特性及低电压穿越控制方法展开研究，具体内容包括：1、电网对称及不对称电压跌落情况下无刷双馈风力发电机故障暂态特性分析。2、提出一种基于间接功率控制策略的磁链跟踪的低电压故障穿越方法。该方法在故障期间控制控制绕组的磁链跟踪功率绕组磁链，实现对机组的保护。优点是①低电压穿越期间电磁转矩小，减小风电机组机械系统的扭切应力冲击；②适用于对称及不对称各种低电压故障；③无需增加硬件。3、提出基于间接功率控制策略的无刷双馈风力发电机空载并网策略。

和目前在风电领域得到广泛应用的双馈电机相比，无刷双馈电机没有电刷和滑环，减小了维护成本，更能满足风电系统的需求。过去十年间对于无刷双馈电机及其控制策略的研究取得了快速发展，使其日渐接近工程应用..提出了一种无crowbar的基于磁链跟踪控制的无刷双馈风力发电机的低电压穿越控制方法。提出了功率绕组幅值和相位分别跟踪的方法，构建了控制系统的结构框图。解析分析了满足磁链跟踪条件下功率绕组有功和无功功率以及电磁转矩的暂态过程。研究结果表明该方法即适用于电网电压对称跌落也适用于不对称电压跌落。最严峻故障情况（电网电压100%对称跌落，故障前电机运行在最高转速）下的实验结果表明，在无需附加任何硬件的情况下，无刷双馈电机成功穿越故障，性能满足最严峻的风电场接入电力系统技术规定。和现有文献相比，所提控制策略具有更好的抑制浪涌电流的能力，且故障穿越期间转矩脉动小，因而大大减小了系统传动链的压力。.提出了一种笼型转子无刷双馈发电机的间接功率控制方法，该控制方法的优点在于：在双静止坐标系实现有功和无功的控制，无需旋转坐标变换，简化了系统结构；对电机参数的鲁棒性较强。样机的实验结果表明，系统具有较好的静态和动态性能。.提出了一种笼型转子无刷双馈电机在任意一个定子绕组静止坐标系观测另外一个定子绕组磁链的方法，该方法简单且不需要坐标变换，因此易于在实际系统中实现。仿真和实验结果表明，该方法观测结果比较准确，可以满足实际系统对于动态性能的需求。.提出一种基于控制绕组磁链控制的无刷双馈感应发电机的空载并网方法。实验结果表明，该方法实现了功率绕组电压幅值和频率的自动调调节，实现了柔性空载并网。该方法具有调节过程稳定，所需时间短的优点。.到目前为止，无刷双馈电机的设计方法尚不成熟，课题组正在开发笼型无刷双馈电机基于路算的设计方法。