【作者】 荆龙；

【导师】 王毅； 汪至中；

【作者基本信息】 北京交通大学 ， 电力系统及其自动化， 2008， 博士

【摘要】 鼠笼式异步电机风力发电系统包括恒速运行的失速型风力发电系统以及由鼠笼异步电机和背靠背的四象限变流器组成的变速恒频风力发电系统,他们的共同点是都存在齿轮箱-传动轴这一脆弱环节,在频繁的转矩冲击和大幅度波动下容易损坏。论文中系统地研究了以鼠笼式异步电机作为发电机的一类风力发电系统中,传动链的受冲击情况以及以减少转矩冲击、提高风能利用率为目的的控制方式优化研究。论文中首先结合与金风科技合作开展的750kW失速型风力发电机组受冲击情况测量及控制参数优化的工作,对750kW失速型风力发电机组传动系统建立了精确的柔性数学模型,在此模型的基础上,对机组并网,停机过程进行了仿真。结合风场实验数据,分析了机组并网时产生电冲击、机械冲击的原因和解决方案;提出了基于转速梯度法和分段控制的并网控制策略。对停机时的冲击以及转矩震荡进行了分析,对停机过程进行优化。经过控制优化,大大改善了s48/750kW机组的运行可靠性。针对由鼠笼异步电机组成的变速恒频风力发电系统,建立了变速变距风力发电机组吸收风功率的模型。对并网和停机时的传动链受力情况进行了分析;对运行过程的转速控制方式和转矩控制方式下的工作情况和转矩冲击进行了详细研究,指出各自特点及适用范围。讨论了在转速控制方式下,减小由风速突变而引起的转矩冲击的方法。为转速控制方式提出了基于专家系统的改进型MPPT控制算法,讨论了该方法的实现,以及该方法在力矩控制方式中的应用。针对基于专家系统的MPPT设计了一种基于混合灵敏度函数的转速调节器,验证了该调节器的性能以及能够减少干扰带来的转矩波动。给出了改进型MPPT控制方法的仿真验证结果,表明该方法具有很好的快速性,稳定性和更高的风能利用率。建立了电网侧逆变器的状态空间模型,在该模型的基础上讨论了开关频率固定的电流跟踪控制方法,并利用级数的方法证明了该方案的稳定性。并使用自寻优的方法确定了控制环节的参数,使系统具备了更好的动态响应。根据风力发电系统的特点,讨论了基于转子磁场间接定向电流型矢量控制系统。分析了这种方法应用在风力发电中所涉及到的各个环节。论文分析了电流跟踪控制方法在感应电机控制中的应用,并且将FIR数字滤波器应用在其中,使用FIR数字滤波器,使得电流跟踪控制方法得以实现,并且提高了系统的稳定性和抗干扰性。构建了室内模拟风力发电的实验系统,简洁而有效。针对论文提出的方法进行了实验,给出了实验结果。更多还原

【Abstract】 The dissertation focuses on the torque analysis on transmission system and control optimization to reduce torque shock,and improve the utilization of the wind power,when apply the squirrel cage asynchronous motor(SCAM) in wind power generation system.The SCAM wind power generation system conclude two kinds of scheme:stall regulated wind power system which run at fixed speed,and variable speed constant frequency wind power system(VSCF),which combined with SCIM and back to back 4 quadrant converter.The two kinds of system both include the gear box and transmission shafts,which is a weak point,and easy to be damaged.Combine with the work of the optimization control of the 750kW wind turbine, the flexible shaft model of the 750kW stall regulated wind power system is set up. Using this model,procedure of cut-in and cut-off are simulated.With the experimental data in wind farm,the causes of the electrical and mechanical shock while cut-in are analyzed.Also the solutions to reduce the shock are given out.Speed gradient and sectional control methods are put forward to optimize the cut-in procedure.Torque oscillation while cut-off is analyzed,and procedure of cut-off is optimized to reduce the oscillation.Through these measures,the operation reliability of s48/750kW wind turbine is improved greatly.The wind power absorption model of VSCF system is built up.Procedure of cut-in and cut-off for VSCF system and torque on transmission system are simulated. The speed control mode and torque control mode are given out in operation procedure. The two modes are compared in detail.The method to reduce the torque shock while change of the wind speed is researched.Maximum power point tracking(MPPT) Control algorithm based on expert system is proposed for speed control mode.Swiftness,stability,and efficiency of this method are tested by simulation and experiment.Using mixed sensitivity function,a speed regulator is designed for the MPPT block.Torque shock brought by speed measure error and MPPT disturbers brought by speed fluctuate are reduced greatly.The space model of 4-quadrant converter(4QC) is used to analyze the current PWM method of supply side converter.The stability of this method is proved.Using self-optimized method,the control parameters are determined. An indirect vector-control system of SCIG is presented in this dissertation according to feature of wind power system.Current PWM control method is applied in the control of the machine.The FIR is used in the system to obtain the reliability and stability.An experiment system was built up in the lab,which can simulate the wind power generation conveniently.The experiment result and simulation result are give out.更多还原