直驱风力发电机运行控制及低电压穿越技术研究

发布时间：2018-02-09 18:52

本文关键词： 永磁直驱风力发电最大风能追踪解耦控制低电压穿越变流器　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着能源危机的日益加剧,风电作为绿色电力能源,是解决能源问题的关键所在。永磁直驱风力发电机因其运行效率高、低电压穿越能力强而备受关注,得到了越来越广泛的应用。本文以永磁直驱风力发电机为研究对象,深入研究了稳态时永磁直驱风力发电机机侧变流器和网侧变流器的控制策略,并对故障情况下变流器的低电压穿越进行了分析,主要工作内容有： (1)对永磁直驱风力发电系统中的基本组成元件建立了详细的数学模型,并提出了主电路中元件参数的选择方法。根据对数学模型分析,在PSCAD/EMTDC软件环境下,建立了各个元件仿真模型。 (2)设计了机侧变流器的基于转子位置角定向的控制策略,控制策略实现了永磁直驱发电机的转矩电流与励磁电流解耦,并且能够实现最大风能追踪功能。在PSCAD软件中建立了适合更大规模仿真需求的机侧控制简化模型,验证了控-制策略的正确性及有效性,同时也大大提高了仿真运行速度,为机群建模仿真提供了条件。 (3)根据网侧变流器的数学模型,设计了网侧变流器的控制策略。控制目标是完成有功、无功的解耦控制及稳定直流电压。在PSCAD软件中,建立了1.5MW永磁直驱风力发电系统的仿真模型,并对阶跃风速下的风电机组运行进行了仿真。仿真结果显示,永磁直驱风力发电系统能够实现最大风能追踪,直流母线电压稳定,网侧电流谐波小,网侧运行在单位功率因数下。验证了机侧和网侧变流器控制策略的有效性。可供工程应用参考。 (4)对电网对称故障和不对称故障时的直驱风电机组低电压穿越技术进行了研究。对于电网发生对称性故障时,提出了发电机的低电压穿越控制策略。采用限制电机发出功率的控制算法,实现低电压穿越功能。该方法相对于现在应用较多的crowbar投切及直流卸荷电路的低电压穿越方法,不需要对电机主电路进行改造,减少了保护电路部分维护工作量。对于电网发生不对称故障的情况,提出了基于双dq坐标系下的不对称控制策略,实现抑制有功功率震荡、稳定直流电压的功能。对以上两种控制策略,在PSCAD中进行了仿真验证,仿真结果证明了控制策略的有效性。具有工程应用的参考价值。
[Abstract]:As the energy crisis intensifies day by day, wind power, as a green power energy, is the key to solve the energy problem. Permanent magnet direct drive wind turbine has attracted much attention because of its high operating efficiency and strong ability of low voltage traversing. This paper takes permanent magnet direct drive wind turbine as the research object, and deeply studies the control strategy of generator side converter and grid side converter of permanent magnet direct drive wind generator under steady state. At the same time, the low voltage traversing of the converter under the condition of fault is analyzed. The main work contents are as follows:. 1) A detailed mathematical model of the basic components in a permanent magnet direct drive wind power generation system is established, and a method for selecting the component parameters in the main circuit is proposed. According to the analysis of the mathematical model, under the environment of PSCAD/EMTDC software, The simulation models of each component are established. The control strategy based on rotor position angle orientation is designed, and the torque current and excitation current of permanent magnet direct drive generator are decoupled by the control strategy. And it can realize the function of maximum wind energy tracing. The simplified model of computer side control is established in PSCAD software, which verifies the correctness and effectiveness of the control and control strategy, and at the same time greatly improves the running speed of the simulation. It provides conditions for cluster modeling and simulation. 3) according to the mathematical model of the grid-side converter, the control strategy of the grid-side converter is designed. The control goal is to complete the decoupling control of active and reactive power and to stabilize the DC voltage. The simulation model of 1.5MW permanent magnet direct drive wind power generation system is established, and the operation of wind turbine under step wind speed is simulated. The simulation results show that the permanent magnet direct drive wind power generation system can achieve maximum wind energy tracing, and the DC bus voltage is stable. The current harmonics on the grid side are small and the network side operates under the unit power factor. The validity of the control strategy of the converter on the machine side and the network side is verified. It can be used as a reference for engineering application. In this paper, the low-voltage traversing technology of direct-drive wind turbine with symmetric fault and asymmetric fault is studied. The low voltage traversing control strategy of generator is proposed. The low voltage traversing function is realized by using the control algorithm which limits the output power of the generator. This method is compared with the low voltage traversing method which is widely used in crowbar switching and DC unloading circuits. There is no need to reform the main circuit of the motor, and the maintenance workload of the protection circuit is reduced. For the case of the asymmetric fault in the power network, an asymmetric control strategy based on the double dq coordinate system is proposed to suppress the active power oscillation. The function of stabilizing DC voltage. The simulation results of the above two control strategies in PSCAD show the effectiveness of the control strategy and have reference value in engineering application.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM315

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