【作者】 房善新；

【导师】 郝晓弘；

【作者基本信息】 兰州理工大学 ， 电力系统及其自动化， 2010， 硕士

【摘要】 随着科技的进步和自动化程度的提高,对电能质量敏感的用电设备越来越多,因而电力用户对供电质量提出了更高的要求。而动态电压恢复器(DVR)可以有效的解决电网中的电压跌落、暂升、短时谐波等暂态电压质量问题。因此,对其研究具有极大的理论和现实意义。本文在分析DVR工作原理和主电路结构的基础上,根据低压配电网的特点,确定了基于相电压补偿的DVR主电路结构,同时还研究了几种常用的电压补偿策略。由于电压跌落的检测环节对DVR的补偿性能具有很大的影响,文中详细分析了基于dq变换的三相和单相电压检测方法,针对检测中所用的低通滤波器存在响应时间和检测精度之间的矛盾问题,提出了一种新型的滤波器,它由一个高截止频率的低通滤波器和一个带阻滤波器串联组成,理论分析和仿真验证表明其具有更好的响应速度和检测精度,能够满足DVR电压检测的需要。针对传统的DVR前馈控制方法存在稳态误差、对电网中的扰动不敏感、负载适应性差等缺点,提出了一种无模型自适应控制的方法,仅通过负载电压和系统输入电压的数据来确定控制器的参数,无需建立系统的数学模型,只通过一个在线调整的参数,来达到抑制系统干扰,稳定负载电压的目的。仿真结果表明这种控制方法比前馈控制方法具有更高的稳定裕度,具有很好的抗干扰能力和负载适应性,而且其响应时间也比较迅速,能够应用于DVR的控制系统。更多还原

【Abstract】 As the advances of technology and increased of automation. The electrical equipment which is sensitive to power quality are more and more. Therefore the power users put forward higher requirements to the quality of power supply. Dynamic Voltage Restorer (DVR) can effectively solve the problems of transient voltage quality such as voltage sag, swell, short time harmonic in power system. Therefore, the study of DVR have Great theoretical and practical significance.Based on the analysis of the main circuit and principle of DVR, and according to the characteristic of low-voltage network, this paper confirms the main circuit of DVR which is voltage compensation based on phase. At the same time also studied the voltage compensation strategy for several common of DVR.Because of the detect section of voltage sag have a great impact for the compensation of DVR. This paper detailed analysis the three phase and single phase Voltage detection methods based on dq alternate method. A new filter, use a high cut off frequency low pass filter in series with a band stop filter make up, is proposed to resolve the contradictory problem of response time and detection accuracy in traditional low pass filter in detect. the theoretical analysis and simulation verification show that it have better response speed and detection accuracy,it can meet the needs of DVR voltage detection.A new control method, a model-free adaptive control,is proposed to resolve the steady-state error, insensitivity to the disturbance of power system, adaptive load is bad which is existed in feedforward control method of traditional, it only use the the data of load voltage and input voltage to determine the controller parameters, no need to establish the mathematical model of the system, Only by adjusting the parameters of a line, to achieve interference suppression system, the purpose of load voltage stability.simulation results show that this method than the feedforward control method has a higher stability margin, has good anti-interference ability and load adaptability, and its response time is relatively fast, can be used in DVR control system.更多还原