双馈风力发电机的故障穿越技术与仿真研究

发布时间：2018-04-20 12:03

本文选题：双馈感应式风力发电机 + 低电压穿越　；参考：《中北大学》2014年硕士论文

【摘要】：随着风电装机容量的不断增加，，风电系统与电网之间的相互影响也越来越大，其中风电系统的故障穿越能力成为影响电网安全和稳定运行的重要因素之一。本文以目前广泛应用的双馈风力发电机作为研究对象，重点研究了双馈风电系统在电网故障下的穿越运行，包括低电压穿越（LVRT）和高电压穿越（HVRT）。主要从改进控制策略和增加硬件保护电路两个方面进行了研究，其中低电压穿越包括对称故障下的穿越和不对称故障下的穿越。针对双馈感应发电机（DFIG）的低电压穿越，在数学建模和故障暂态分析的基础上设计了对称故障下的定、转子变换器协同控制方法；设计了不对称故障下DFIG网侧变换器PD电流调节器控制策略和转子变换器的PI-R电流调节器控制策略；设计了一种可统一应用于对称故障和不对称故障的双馈电机稳态矢量控制暂态直接转矩控制的控制方法。对常规的硬件保护Crowbar电路和Chopper电路，研究了其对于低电压穿越的保护效果。针对双馈电机高电压穿越，阐述了电压升高的原因并对电压骤升下的DFIG进行了暂态分析；列举了应对高电压穿越的改造思路，包括改进控制策略，增加硬件保护Crowbar电路，增加风电场无功补偿装置和超级电容的应用；设计了DFIG高电压穿越时网侧变换器的控制思路和转子侧变换器的控制思路；设计了无功补偿装置（STATCOM）的控制方法。实际生产中若针对高、低电压故障分别设计控制方法，则其控制的实用性会较差，对此本文得出结论应该在低电压穿越的同时考虑高电压穿越，由一套控制方法应对不同故障情况。电网故障程度较轻时控制策略改进穿越而故障程度较深时则投入硬件保护电路实现穿越。为了验证所设计的穿越方法和控制策略，在Matlab/Simulink上建立了一个1.5MW的双馈感应风机模型，对其在低电压故障和高电压故障的情况进行仿真。结果表明本文所设计的不同控制策略的正确性。
[Abstract]:With the increasing of wind power installed capacity, the interaction between wind power system and power grid is becoming more and more serious. Among them, the fault passing ability of wind power system becomes one of the important factors that affect the safe and stable operation of power grid. In this paper, the widely used doubly-fed wind turbine is taken as the research object, and the crossing operation of doubly-fed wind power system under the fault of power network is studied, including low voltage traversing LVRTT (low voltage traversing) and high voltage traversing HVRTT (HVRTT). In this paper, the improvement of control strategy and the increase of hardware protection circuit are studied. The low voltage traversing includes symmetric fault traversing and asymmetric fault traversing. Aiming at the low voltage traversing of DFIGs, based on mathematical modeling and fault transient analysis, a cooperative control method for stator and rotor converters with symmetric faults is designed. PD current regulator control strategy of DFIG grid-side converter and PI-R current regulator control strategy of rotor converter under asymmetric fault are designed. A control method for transient direct torque control (DTC) of doubly-fed machine based on steady-state vector control is designed, which can be applied to symmetric and asymmetric faults. The protection effect of conventional hardware protection Crowbar circuit and Chopper circuit for low voltage traversing is studied. In view of high voltage traversing of doubly-fed machine, the reason of voltage rise is expounded and transient analysis of DFIG under voltage sudden rise is carried out, and the retrofit ideas to deal with high voltage traversing are listed, including improving control strategy, adding hardware to protect Crowbar circuit. The application of reactive power compensator and super capacitor in wind farm is increased. The control thought of DFIG high voltage traversing grid-side converter and rotor side converter are designed. The control method of reactive power compensation device is designed. In actual production, if the control methods are designed separately for high and low voltage faults, the practicability of the control will be poor. In this paper, it is concluded that the high voltage traversing should be considered at the same time as low voltage traversing. A set of control methods is used to deal with different fault situations. The control strategy is improved when the fault degree is low and the crossing is realized by hardware protection circuit when the fault degree is deep. In order to verify the designed traversing method and control strategy, a double-fed induction fan model of 1.5MW is established on Matlab/Simulink, and the simulation is carried out in the case of low voltage fault and high voltage fault. The results show that the different control strategies designed in this paper are correct.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM315

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