双馈风电机组减载能力分析及一次调频协调控制研究

发布时间：2019-04-23 22:50

【摘要】：随着风电大规模的并网,电网频率稳定问题日益严峻。对于目前广泛采用的双馈异步风力发电机组,利用转子侧变流装置实现变速恒频,从而当系统频率发生变化时,其转子转速无法响应电网频率的变化,而且机组通常运行于最大功率跟踪模式下,使其无法提供额外的有功功率参与频率调节。目前,对风电机组一次调频的研究主要集中在功能实现方面,本文主要针对双馈风电机组一次调频能力方面展开研究。首先,分析了双馈风电机组的工作原理并建立其数学模型,包括风速模型、风力机模型、轴系系统模型、发电机模型及控制系统模型。在此基础上,研究了转子侧换流器定子磁链矢定量定向控制策略、网侧换流器电压矢量定向控制策略和桨距角控制策略。其次,介绍了电力系统频率调节的基本原理和一次调频的基本要求,给出了双馈风电机组参与系统一次调频的原理方案,并对转子动能控制和功率备用控制两种频率控制方法进行了分析和比较。然后,根据不同风速条件,制定了超速控制和桨距角控制结合的减载控制策略。低风速时,采用超速控制进行减载;中风速时,采用超速控制和桨距角控制结合的减载控制策略;高风速时,采用浆距角控进行减载。并建立双馈风电机组一次调频控制系统仿真模型,进行仿真分析。得出了减载控制可以在不同控制模式下都能为系统调频提供足够的备用容量。最后,在三种减载控制策略的基础上,结合发电机转子动能控制,实现双馈风电机组次调频协调控制策略,并与传统的组合控制策略进行了仿真对比。仿真结果表明,协调控制策略不仅使风电机够的备用容量,而且具有良好的频率响应特性。
[Abstract]:With the large-scale wind power grid-connected, the problem of power grid frequency stability is becoming more and more serious. For the widely used doubly-fed asynchronous wind turbine, variable speed constant frequency (VSCF) is realized by rotor side converter, so that the rotor speed can not respond to the change of power network frequency when the system frequency changes. Moreover, the unit usually operates in the maximum power tracking mode, which makes it impossible to provide additional active power to participate in frequency regulation. At present, the primary frequency modulation of wind turbine is mainly focused on the realization of function. This paper mainly focuses on the primary frequency modulation capability of doubly-fed wind turbine. Firstly, the working principle of doubly-fed wind turbine is analyzed and its mathematical model is established, including wind speed model, wind turbine model, shaft system model, generator model and control system model. On this basis, the stator flux vector oriented control strategy, voltage vector oriented control strategy and pitch angle control strategy of rotor side converter are studied. Secondly, the basic principle of frequency regulation of power system and the basic requirements of primary frequency modulation are introduced, and the principle scheme of doubly-fed wind turbine participating in primary frequency modulation of the system is given. Two frequency control methods, rotor dynamic energy control and power standby control, are analyzed and compared. Then, according to different wind speed conditions, a load-reducing control strategy combining overspeed control and pitch angle control is proposed. At low wind speed, overspeed control is used to reduce load; medium wind speed is controlled by combination of overspeed control and pitch angle control; at high wind speed, slurry distance angle control is used to reduce load. The simulation model of primary frequency modulation control system of doubly-fed wind turbine is set up, and the simulation analysis is carried out. It is concluded that the load shedding control can provide sufficient reserve capacity for FM system in different control modes. Finally, on the basis of three kinds of load-reducing control strategies, combined with generator rotor dynamic energy control, the sub-FM coordinated control strategy of doubly-fed wind turbine is realized, and the simulation results are compared with the traditional combined control strategy. The simulation results show that the coordinated control strategy not only makes enough backup capacity of wind turbine, but also has good frequency response characteristics.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM315

【参考文献】