【作者】 李杰；

【导师】 陈国呈；

【作者基本信息】 上海大学 ， 电力电子与电力传动， 2009， 博士

【摘要】 随着全球能源危机与环保问题的日益突出,以风能、太阳能等可再生能源为代表的新能源开发利用越来越受到人们的重视。由于全球风能资源丰富加上风力发电成本较低,因此风力发电已成为二十一世纪最具大规模开发利用的新能源之一。与传统风力发电系统相比,直驱式风力发电系统由于采用了多极低速永磁同步发电机从而取消了增速齿轮箱,降低了维护费用,提高了可靠性,而且利用变速恒频发电方式能大大提高风能利用率,所以更加适合于目前对风力发电系统高效率、大容量、高可靠性的要求。因此,直驱式风力发电系统正逐渐得到人们的青睐,各国学者争相研究。本文对几种直驱式风力发电系统变流器的拓扑及其控制策略进行了深入研究,建立起一套仿真与实验平台,进行了相应的仿真和实验验证。文章首先对国内外风力发电系统及变速恒频风力发电技术的研究现状和发展趋势做了全面综述。分析了风力机的基本特性和最大风能捕获的基本思路,提出了在实验室条件下利用变频器驱动的异步机来定性模拟风力机的方法,为相关实验研究提供了基础。对直驱式风力发电系统所用的全功率网侧三相PWM逆变器的控制策略进行了深入细致研究,阐述了幅相控制的基本原理,并针对逆变器启动时刻并网冲击电流大和动态响应较慢的不足,提出了开启电压预测控制和电流前馈控制两种方法,实验证明提出的方法能有效抑制并网瞬间的电流冲击,实现柔性并网。详细地阐述了一种固定开关频率的直接电流控制策略,推导了网侧电压型PWM变换器在同步旋转坐标系下的数学模型,对SAPWM调制波做了傅立叶分析,在此基础上提出了一种零轴谐波注入法以提高直流母线电压利用率,进行了仿真和实验验证。阐述了基于虚拟电网磁链的网侧PWM变换器无电压传感器控制策略,提出了一种虚拟电网磁链观测稳态误差补偿方法。根据机侧整流装置的不同,分别对发电机输出接无源整流装置和接有源整流装置两类拓扑结构进行研究,对于前者,首先分析了其工作特性,然后分别研究了基于boost升压电路和基于Z源逆变器的直驱式风力发电系统拓扑及其控制方法、最大功率点跟踪策略等,并给出了仿真和实验结果。对于后者,在详细分析了永磁同步机数学模型的基础上设计了转子磁链定向矢量控制系统和使发电机效率尽量优化的最大功率点跟踪策略,并进行了仿真和实验。最后,针对发电机采用无源整流结构时由于整流桥特性及交流电抗引起的发电机电流谐波大、功率因数低、效率低等缺点,研究了一种基于磁能恢复开关的发电机交流电抗补偿方法,仿真结果证明该补偿方法效果良好。更多还原

【Abstract】 With the increasingly serious global energy crisis and environmental pollution, the development and utilization of renewable energy sources such as wind energy and solar energy are attracting more and more attention. For the relatively lower cost and abundant global resources, wind power generation has become one of the most promising renewable energy that could be applied on a large scale. A low speed multi-polar Permanent Magnet Synchronous Generator (PMSG) is utilized in the Direct-Drive (DD) Wind Power Generation System (WPGS) to eliminate the up-speed gearbox that is always included in traditional WPGS. The DD-WPGS has advantages such as low maintenance costs, high reliability. Furthermore, it can greatly improve the wind power capturing capability when it works in Variable Speed Constant Frequency (VSCF) mode. The PMSG-WPGS meets the requirements such as high efficiency, large capacity, high reliability and it is becoming a research hotspot in many countries. In this dissertation, couple of topology and their control strategy of the converter for DD-WPGS are comprehensively investigated. A simulation and experimental platform is built up and a lot of simulation and experimental results are obtained based on it.At the beginning of this dissertation, the domestic and overseas research status of WPGS structure and VSCF technology are summarized compendiously. Then the performance characteristic of wind turbines (WT) and the operation principle of optimum utilization of wind energy are addressed, and a method of using Asynchronous motor to qualitatively simulate WT is presented, which establishes foundation for relevant experimental study. This dissertation carries on the deep study on the control strategies of the grid-side three-phase PWM inverter. The vector regulating principle of the phase and amplitude control for three-phase grid-connected inverters is represented. To solve the problem of heavy impact current and slow dynamic response, the start voltage prediction control and the current feed-forward control are proposed, which improve the dynamic performance of the system in the phase and amplitude control. The experimentation carried out on a three-phase grid-connected inverter proved the validity of proposed methods. A direct current control strategy with fixed switching frequency is studied. The mathematic model of three-phase grid-connected inverter in synchronous rotating coordinate system is built. Based on Fourier analysis of Saddle Pulse Width Modulation (SAPWM) wave, a 0-axis harmonic injection method is presented for enhancing DC link voltage utilities. The simulation and experiment has been presented to verify the proposed theories. A virtual-flux-based sesorless control strategy of three-phase PWM converter is studied, and a teady-state error compensation method for virtual flux observer is proposed. Then, the dissertation does research on two kinds of the WPGS topology. One is the topology including PMSG linked the passive rectifier, and the other is topology including PMSG linked the active rectifier. For the former, the performance characteristic of the passive rectifier is analyzed at first. Then the system structure, control method and the MPPT strategy are researched for the topology respectively based on boost converter and Z-source inverter. Simulation and experimental results is provided. For the latter, by analyzing the mathematic model of PMSG, a rotor flux oriented vector control strategy and a MPPT strategy based on optimizing the efficiency of PMSG is designed. The simulation and experimental results prove the validity and feasibility of the presented control method. At last, to solve the problems of high harmonic and low power factor for the PMSG in the first kind of topology, a method of compensating PMSG’s reactance voltage based on a novel circuit called Magnetic Energy Recovery Switch (MERS) is researched, and the simulation results prove that it has good compensation effect.更多还原