Next , the pwm - fcl ' s merit of producing low harmonics and fast response owing to pwm is demonstrated in theory and simulation . and a simulation and academic analysis proved the fact that pwm - fcl could restrain the spread of the harmonic within the distribution network 接着，分析了pwm技术控制下的fcl在运行过程中所具有的产生谐波分量小、响应速度快的特点，指出了它能抑制配电网中谐波分量的传播。
A data collection and control : high speed direct sampling and effective value calculation of ac voltages and currents , calculation of active power reactive power power factor , collection and transmission of states , select - check - execute of control output 交流电压电流信号的高速实时采样和有效值计算有功无功功率因数计算各交流量的2 15次谐波分量及谐波总量计算遥信量的采集及上送遥控返校及执行。
Two generating methods of compensation current are also proposed for the purpose of eliminating detuning or limiting harmonic voltage contents , in which the compensation current is the weighted superposition of filter harmonic currents or voltages and the regulating factor 针对消除失谐或限制谐波电压含量的不同控制目标，提出了谐波磁通补偿电流的两种生成方法，补偿电流分别是滤波器电流或母线电压中各次谐波分量与调节系数的加权合成。
The conventional switching power supply usually use a diode rectifier followed by a bulk capacitor to convert ac voltage to dc voltage , resulting in the pulsating waveform of the input ac line current , low power factor ( generally 0 . 65 ) and high harmonic line current 传统的开关电源设备通常采用二极管桥来进行整流和一个较大的电解电容来进行滤波以实现输入电压的交直流转换，导致输入电流为一个很窄的脉冲波并含有较多的谐波分量，功率因数变低(通常只有0 . 65 ) 。
Based on the adaptive interference canceling theory and the concept of space vector , an adaptive fundamental positive / negative sequence component and harmonic component detecting method is developed . due to the close loop structure , this method has quite good robustness , and can meet the requirement of the asymmetrical control of hvdc - vsc well 运用自适应干扰对消原理和空间矢量的概念，提出了一种基波正序分量、基波负序分量及谐波分量的自适应检测方法，并进行了详细的理论分析，为研究hvdc - vsc的不对称运行控制奠定了基础。
The thesis uses sql server 6 . 0 database , standard sql access interface , and oriented - object program language vc + + to implement our electric network dispatching message management system . the system can operate like this : automaticly check if having data files come ; discriminate file type ; automaticly read data into database ; rapidly give out the precise analysis results , including waveform display , fault component calculating ; select fault phase ; distinguish fault type ; precisely fault allocate ; run all kinds of database administration , like antomatic add - on , automatic deletion , amendment , inquiry by different conditions ; print all kinds of outcome and keep them into database ; share data resource by web technique ; deal with complex faults . the whole system i finished will be powerful technic support for dispatching operation 本文采用标准的sqlserver6 . 0数据库，标准sql访问接口和面向对象编程工具vc + +进行编程,实现了集数据库、分析计算、图形化界面、网络通讯于一体的电网故障录波信息管理及故障诊断系统，该系统能够在每次故障后自动查询有无数据文件的到来;能够对传送到调度端的数据文件分析其类型;能够按comtrade格式自动地将大量数据信息完整地填入数据库中;能够进行故障选相,故障类型判别和故障精确定位;能够快速地对故障做出精确的分析,计算各次谐波分量,有无功和视在功率,功角,序分量等;能够对数据库进行各项管理,如浏览,自动添加和删除,修改和按各种不同条件进行查询;能够将计算结果,各种表格图形打印出来和保存进数据库中;能够将计算分析结果通过web技术为其他部门提供共享数据资源
This paper focuses on the control strategies to improve the performance of the three - phase ac - dc pwm voltage - source - converters ( vsr ) under unbalanced power supply . the problems such as negative sequences current , voltage and current harmonics and un - constant ( un - smooth ) power flow from ac to dc side are discussed in this paper . the analytical solutions for negative sequence current and harmonic current elimination are obtained by fully feed - forward of negative sequence voltage and producing a non - harmonic current command of the inner - loop 电网不平衡时，基于电网平衡为约束条件设计的三相vsr将出现不正常运行状态，比如三相vsr交流电流中出现负序分量，使交流电流严重不对称；直流电压和交流电流中出现非特征谐波分量，使直流电压和交流电流波形发生严重畸变；三相vsr从电网吸收不平衡的瞬时功率等一系列问题。
It mainly includes following aspects : in this paper , firstly implication of wavelet analysis in signal harmonic component extraction is presented in detail , and on this foundation signal given frequency band component extraction method is proposed . then we investigate frequency aliasing phenomenon , reason why frequency aliasing phenomenon is easy happened when wavelet is implied in field of motor fault diagnosis , and frequency bands where frequency aliasing phenomenon is easer happened , and put forward approved morlet wavelet analysis method which can effectively alleviates frequency aliasing phenomenon . third we set up vibration signal detected system , design experiments to obtain three groups of fault signals : eccentricity fault , mixed fault of eccentricity plus mild rub , mixed fault of eccentricity plus moderate rub , and process these data using analysis method proposed in this paper 首先对论文的选题以及相关背景进行了探讨,并对相关的小波基础理论进行了阐述,主要针对感应电动机的偏心故障和偏心+碰摩复合故障形式及相关的应用算法进行了详细探讨,主要工作内容包括下面几个方面:在论文中,首先对小波分析在信号的谐波分量提取中的应用进行了研究,在此基础上,提出了信号的特定频带成分的提取方法;研究了小波分析的频域混叠现象,探讨了小波分析应用于电机故障诊断领域时易发生频域混叠现象的原因,以及混叠现象较易发生的频带,提出了可以有效减轻频域混叠现象的改进的morlet小波分析方法;搭建了振动信号检测系统,设计实验采集得到三组故障数据:偏心故障,偏心+轻微碰摩复合故障,偏心+中度碰摩复合故障,并对这些数据应用本文提出的分析方法进行信号处理,提取出的特征参数可有效区分这两种故障形式;研究了基于matlab和labview的混合编程方法,完成了电机故障检测系统的软件开发。
This method can inspect the harmonic component and reactive power immediately . based on this prototype , matlab , which is a simulated tool for power system , is used to prove it . experimental results are presented to conform the effectiveness of the apr 本设计用先进的仿真软件工具matlab中的电力系统仿真工具箱对基于这种方法的有源滤波器进行仿真，仿真结果表明基于瞬时无功功率理论设计的有源滤波器装置能够有效检测出谐波分量，并可以抑制谐波分量和进行无功补偿。
Abstract : it provides a kind of new nonlinear integrator and its mathematical model . its frequency responses is disscussed by the harmonics linearization method . its phase lag is found to be only 27 . 6 , all high order harmonics are very small , and it is very resistant to disturbances . by using it , an two - objective optimum control system is designed . it has very good control performances and will have good prospects in application 文摘:提出一种新型的非线性积分器，给出它的数学模型，并用谐波线性化原理讨论它的频率特性，其幅频特性起积分作用，而相位滞后仅27 . 6 ，高次谐波分量小，抗干扰能力强.应用这种积分器设计了一个双目标优化的二次优化系统.仿真结果表明，系统的控制性能好，具有广泛的应用前景
