永磁直驱风电变流器电流控制系统的设计与优化研究

发布时间：2018-01-04 09:16

本文关键词：永磁直驱风电变流器电流控制系统的设计与优化研究　出处：《华中科技大学》2014年博士论文　论文类型：学位论文

【摘要】：随着传统化石能源的日益枯竭和全球生态环境的严重恶化,可再生能源的并网发电已成为当前清洁能源利用的研究热点。其中,风力发电得到了世界各国和地区的重视。永磁直驱式风力发电机组具有可靠性好、发电效率高、故障穿越能力强等技术优点,而电流控制则是决定上述机组运行性能的关键所在。为此,本文围绕永磁直驱式风力发电机组,针对其电流控制系统(包括滤波器、电流调节器和锁相环等因素在内)的设计和优化方法进行深入、细致的研究,并取得了以下研究成果： (1)针对T型LCL滤波结构,在满足并网要求的前提条件下,本文提出了一种尽量减少电感磁性元件的滤波器参数优化方法。首先,为避免滤波器谐波衰减特性的过设计(滤波电感设计冗余),本文精确分析了空间矢量调制策略下的谐波电压分布特性,并给出了一种谐波电压幅值的计算方法；在此基础上,定义了谐波畸变系数以衡量各次谐波电压对并网电流畸变的影响程度；随后,基于LCL滤波器的数学模型,建立了滤波器参数设计的约束条件,通过递推迭代的设计方式计算并网变换器的谐波最大工作点,并结合图示法优化设计滤波器的参数组合。基于该设计方法,能够准确设计滤波器的谐波衰减特性,有效地降低了滤波电感的设计冗余。 (2)为了改善并网电流控制的静态和暂态响应特性,针对高阶的LCL型并网变换器的电流控制系统,本文提出了一种考虑锁相环性能影响的电流环调节器参数设计和优化方法。首先,考虑数字控制延迟和电网线路阻抗的影响,在连续域内建立了并网电流控制系统的精确静态模型,由此得到准确反映系统响应特性的幅值裕度、相位裕度和静态误差目标函数；在此基础上,根据系统要求适应的电网环境和所需满足的量化性能指标,通过图示法直接得到同时满足各项性能要求的参数取值区域。随后,考虑锁相环动态过程的影响,建立了并网电流控制系统的暂态模型。将其暂态特征方程作为优化设计系统暂态响应特性的目标函数,并进一步通过根轨迹法对已有参数取值区间进行优化,得到性能更优的控制器参数组合。于此同时,本文还提出了一种基于滤波电容支路电压正序分量的前馈控制方法,有效提高了并网电流控制对电网电压扰动的抑制能力。本文以双同步PI电流控制器为设计对象,结合所提控制器参数设计方法和电压前馈控制方法,有效地改善了并网电流控制的动静态响应和并网变换器对电网环境的适应性。 (3)针对永磁同步发电机的矢量控制系统(包括同步定向和定子电流控制),本文提出了一种基于改进的复合预测无差拍控制算法结合同步锁相环的无传感器矢量控制方案。在该方案中,基于传统的无差拍控制算法结构,引入串联补偿的估算反电动势前馈,改善了系统的稳定性、提高了系统的扰动抑制能力；随后,基于Lunberger算法、引入预测权值对定子电流超前一拍预测,有效补偿了数字控制固有一拍滞后的延迟影响；而结合估算反电势的同步锁相环观测模型,则快速准确地实现了转子位置角和转速信息的观测,实现了无传感器的同步定向和速度反馈。在此基础上,考虑数字控制延迟、电机参数失配以及同步定向误差角的影响,建立了无传感器矢量控制系统的精确离散域模型,并基于闭环系统的特征方程,通过Jury稳定判据和闭环根轨迹,对预测无差拍控制器进行优化设计,有效地改善了永磁同步电机无传感器矢量控制的动静态响应和参数鲁棒性。 (4)最后,基于文中所述设计方法,搭建了一套10kW永磁直驱式风力发电系统的模拟实验平台,对永磁直驱式风力发电机组进行了相关的实验验证。实验结果和仿真分析基本一致,证明了本文中所述理论建模分析的正确性以及所提设计和优化方法的有效性。
[Abstract]:With the serious deterioration of the traditional fossil energy exhausting and global ecological environment, and power generation of renewable energy has become a hotspot of current research. The use of clean energy, wind power has been developed countries and regions of the world's attention. Direct drive permanent magnet wind generator group has good reliability, high power generation efficiency, fault crossing ability the advantages, while the current control is the key to decide the operation performance of the unit. Therefore, this paper focuses on the direct drive permanent magnet wind turbine control system, according to the current (including factors including filter, current regulator and phase-locked loop) design and optimization methods of in-depth, detailed research, and achieved the research results are as follows:
(1) for T type LCL filter structure, to meet the requirements of the grid under the premise, this paper proposes a filter parameter optimization method to reduce the inductance of the magnetic components. First, to avoid the design of filter harmonic attenuation (filter inductor design, this paper analyzed the redundancy) accurate harmonic voltage distribution characteristics of space vector modulation under the strategy, and gives the calculation method of harmonic voltage amplitude; on this basis, the definition of the harmonic distortion coefficient to measure the degree of influence of each harmonic voltage on grid current distortion; then, a mathematical model based on LCL filter, and set up the constraint conditions of the filter parameters design, the maximum working point calculation grid harmonic transform designed by way of recursive iteration, and combined with the parameters of filter design method. The optimization design method based on graphic design, can accurately filter the harmonic The wave attenuation characteristic reduces the design redundancy of the filter inductor effectively.
(2) in order to improve the grid current control of static and transient response characteristics, control system for current LCL type grid connected converter of high order, proposed a current regulator parameters considering the effect on the performance of PLL loop design and optimization method. Firstly, considering the influence of the digital control delay and power line impedance, in continuous domain precise static model of grid connected current control system is established, which accurately reflect the response characteristics of the system gain margin, phase margin and static error objective function; on this basis, according to the requirements of the power grid system to adapt to the environment and meet the needs of the quantitative performance index directly, can simultaneously meet the parameters of regional performance required by the law. Then, considering the influence of phase locked loop dynamic process, a transient model of current control system. The grid transient characteristic equation for The objective function characteristics of the transient response of the system design, and further through the root locus method of interval value of existing parameters are optimized to get better performance of controller parameters. At the same time, this paper also proposes a feedforward control method of filter capacitor voltage based on positive sequence component, effectively improve the grid current control inhibition the disturbance of the power grid voltage. Based on dual synchronous PI current controller as the design object, combined with the proposed controller parameter design method and voltage feedforward control method can effectively improve the dynamic response and adaptability of State Grid converter grid current control for grid environment.
(3) for the vector control system of permanent magnet synchronous generator (including directional synchronization and stator current control), this paper presents a composite prediction based on the improved deadbeat control algorithm combining phase locked loop sensorless vector control scheme. In this scheme, the deadbeat control algorithm based on the traditional structure. The introduction of series compensation estimated back electromotive force feedforward, improves system stability and disturbance rejection ability of the system has been improved; then, based on the Lunberger algorithm, is introduced to predict the weight of stator current advance a prediction, effectively compensate for the inherent delay of digital control delay and take effect; combined with the estimated back EMF synchronous ring observation model is fast and accurate observation of rotor position angle and speed, realize sensorless synchronous directional and speed feedback. On this basis, taking into account the number of words control delay, The influence of motor parameters and directional synchronization error angle, established the precise discrete domain model of sensorless vector control system, and based on the characteristic equation of the closed-loop system, through the Jury stability criterion and a closed track, deadbeat controller to optimize the design of prediction, and effectively improve the sensorless vector control of dynamic and static response and the robustness of the parameters of permanent magnet synchronous motor.
(4) finally, the design method based on a set of simulation platform of 10kW permanent magnet direct drive wind power system, the direct drive permanent magnet wind turbines were related experiments. The experimental results and analysis of simulation are basically the same, to prove the correctness of the theoretical modeling analysis in this paper, the effectiveness of the proposed design and optimization method.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM315

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