串联有源电力滤波器的参数选择及仿真

针对典型的三相整流电路对电网产生的影响,介绍了串联有源电力滤波器电路参数设置,探讨了易于数字化的SVP-WM跟踪算法,应用于串联有源电力滤波器内层跟踪控制中的补偿效果。并用比较的方法,重点对串联有源电力滤波器电路进行了计算机仿真分析。     

基于MATLAB的有源电力滤波器控制设计研究

应用MATLAB7.0中的SIMULINK仿真软件对有源电力滤波器系统进行数学建模,通过分析、比较有三相负载电流的输出波形,可检测到其线路中电流的畸变率从原来的28.87％下降至7.83％,证明本次所设计的有源电力滤波器系统能够抑制电网的谐波,说明了有源电力滤波器的谐波抑制和无功补偿的设计可以达到较好的效果,此设计具有一定的实际意义与工程实现价值.     

有源电力滤波器控制策略的研究

伴随着电工电子技术的不断进步,非线性元件在电网架构中得到日益广泛的采纳,从而导致一系列的电网运行难题,其中最为常见的就是电力系统谐波.目前抑制或消除电网谐波的一种有效途径是采用有源电力滤波器,它能动态地抑制谐波,并进行无功补偿.因此,研究有源电力滤波器的控制策略具有重要意义.本文在有源电力滤波器基本原理、基本结构以及有源电力滤波器的分类的基础上,着重介绍研究了三角载波线性控制方法和滞环比较控制方法.利用MATLAB软件中的SIMULNK平台对有源电力滤波器进行了仿真.     

在工程应用中ip-iq谐波检测算法改进与仿真研究

谐波检测是有源电力滤波器非常关键的一环,只有准确地检测到谐波才能进行合理补偿。为了克服有源电力滤波器中ip-iq算法补偿效果在电网波动和负载变化时出现下降的不足,提出了一种改进的ip-iq谐波及无功电流检测方法,在寻找某一小频率范围内的最优滤波器的基础上,根据电网和负载变化以及模糊隶属函数进行实时投切。该算法提高了补偿后的稳态响应。改进后的算法在工程应用中具有很强的帮助作用。通过simulink仿真证明方法的有效性。     

APF PCS有源电力滤波器在补偿与抑制谐波中的应用

APF PCS有源电力滤波器是一种新型的电力电子装置,可对电力系统中的谐波进行补偿．在有源电力滤波器的基本结构、工作原理、APF PCS有源电力滤波器典型应用．及对APF PCS有源电力滤波器补偿与抑制谐波特性分析的基础上,得出了APFPCS有源电力滤波器补偿与抑制谐波较好的效果．     

融合卡尔曼谐波补偿的有源电力滤波器

针对基于有源电力滤波器(APF)在电网中检测谐波时常规的谐波电流检测方法速度慢、精度不高,提出了一种融合卡尔曼型Ip-Iq法检测谐波,在一定程度上减小了检测误差。采用卡尔曼滤波器代替低通滤波器完成滤波,采用融合卡尔曼型Ip-Iq法作为谐波检测的方法 ,并建立了有源电力滤波器的仿真模型,分析电流的波形和谐波畸变率值,验证了所述理论和控制策略的正确性和可行性,仿真结果表明融合卡尔曼型Ip-Iq法能够对谐波进行有效补偿。     

浅谈有源和无源产品在无功补偿与谐波治理中的应用

本文分析了无功补偿和谐波治理的必要性,对各种滤波补偿方案进行比较,分析得知采用将有源电力滤波器和晶闸管投切滤波器联动方式,将谐波抑制和无功功率补偿融为一体,对电网谐波污染和无功损耗均有很好的抑制和补偿作用,为改善电能质量提出了新的解决方案。     

新型并联混合型有源电力滤波器的研究

谐波是电网中的元件产生的附加波形,谐波的损耗能直接反映电网的质量,谐波的危害会影响到电网及设备的安全,介绍一种新型谐波抑制措施,通过分析并联混合型有源电力滤波器的工作原理和结构,推导出了电气原理模型及等值电路;通过仿真参数的设计,绘制出谐波抑制前后的波形,得出新型并联混合型有源电力滤波器能较好地抑制谐波分量,这对提升整个电网的安全和质量具有重要的现实意义。     

浅谈有源和无源产品在无功补偿与谐波治理中的应用简

本文分析了无功补偿和谐波治理的必要性,对各种滤波补偿方案进行比较,分析得知采用将有源电力滤波器和晶闸管投切滤波器联动方式,将谐波抑制和无功功率补偿融为一体,对电网谐波污染和无功损耗均有很好的抑制和补偿作用,为改善电能质量提出了新的解决方案。     

并联混合有源电力滤波器仿真研究

典型的并联混合型电力有源滤波器,是将LC无源滤波器与有源电力滤波器串联再与电网并联的结构。谐波和无功功率主要由LC滤波器补偿,而有源滤波器的作用是改善LC滤波器的滤波特性,克服LC滤波器易受电网阻抗的影响、易与电网阻抗发生谐振等缺点。有源滤波器不承受交流电源的基波电压,因此装置容量小。本文针对典型的并联混合型有源电力滤波器,采用理论推导与计算机仿真相结合的方法对其系统的拓扑结构与工作原理、控制系统和滤波特性等多方面进行了分析研究。并利用Mannitoba HVDC研究中心的软件PSCAD/EMTDC进行了仿真验证。     

Decomposing apparent power and losses in distribution systems with nonlinear loads

The definition of reactive power for non-sinusoidal conditions is a controversial issue. The mathematical treatment of nonlinear loads in power systems is also unsettled. This paper starts with the decomposing of apparent power in,the cases of linear and nonlinear loads. When harmonics are present, apparent power is composed of active power, reactive power, and disturbed reactive power. Linear element can be defined as the element without disturbed reactive power. This definition is based on a practical engineering concept which can separate the contribution from the apparent power into utility-duty part and custom-duty part. The field investigation of home-used facilities was conducted. Also the data acquisition in the 0.4 kV distribution systems was completed. Moreover, the loss increase due to the nonlinear loads was estimated. Nonlinear loads can be a dominant effect with respect to reactive power and power factor. Field data from a number of nonlinear load types indicate that the disturbed reactive power can cause significant losses in utility supply systems.     

电能补偿与控制动态模拟实验系统开发构建

构建了市电、混合能源供电的单母分段三级动态模拟实验系统,实现了负载形式的典型、多样化,兼顾了实验和科研的需要.通过灵活的调整配电系统结构和参数,模拟了不同地区环境下电能质量指标的变化情况,并且为电能质量治理提供了实物的模拟手段,给出了治理前后效果原因分析.     

三相四线制系统中谐波电流实时检测的研究

随着社会的发展,非线性负载尤其是电力电子装置使用的日益增多,使谐波电流和无功电流大量注入电网,本文基于瞬时无功功率理论,提出了零线电流分离法来实现三相四线制系统中谐波电流实时检测,理论分析和仿真结果表明了方法的正确性。     

基于功效系数法的电力电子实验室设备量化管理

针对电力电子实验室设备管理中鲜有对设备进行全面介绍和对其使用情况进行量化建模分析的现状,提出并实践了一种电力电子实验室设备的量化管理方法。根据电力电子实验的需求对电力电子实验室常用设备的种类和特点依次进行介绍,然后通过分析电力电子实验设备功能不同,需要有针对性的购置、管理的特点,剖析了目前电力电子实验室设备管理存在责任意识淡薄、设备使用不当和盲目购置设备的主要问题,进而从评估电力电子实验室设备供需平衡的角度,提出了一种基于功效系数法的量化管理法。实践证明,该方法能客观地评估实验设备的供需匹配关系,避免设备的盲目购置,有力提高科研资金的使用效益,为电力电子实验室设备的购置和科研经费的使用提供了针对性的建议。     

The Decentralisation Debate: Thinking about Power

Comparing the dynamics of centralisation/decentralisation in Belgium and South Africa has the advantage of revealing discrepancies between the public or official rationale for the (re)distribution of power and the probable or eventual effect of this (re)distribution on educational processes and learning outcomes. It can be seen that local empowerment which has been sometimes credited to decentralisation has tended to be rather spurious, for decentralisation instead appears actually to reinforce existing inequities. Using Foucault’s notion of power as complexly relational by nature, the present study explores some of the assumptions underpinning the dynamics of centralisation/decentralisation and the way they are conceived in certain discursive practices. It does so by looking not only at the juridical and administrative distribution of power between the centre and the periphery in education systems, but also at matters of force and governmentality.     

The Decentralisation Debate: Thinking about Power

Comparing the dynamics of centralisation/decentralisation in Belgium and South Africa has the advantage of revealing discrepancies between the public or official rationale for the (re)distribution of power and the probable or eventual effect of this (re)distribution on educational processes and learning outcomes. It can be seen that local empowerment which has been sometimes credited to decentralisation has tended to be rather spurious, for decentralisation instead appears actually to reinforce existing inequities. Using Foucault’s notion of power as complexly relational by nature, the present study explores some of the assumptions underpinning the dynamics of centralisation/decentralisation and the way they are conceived in certain discursive practices. It does so by looking not only at the juridical and administrative distribution of power between the centre and the periphery in education systems, but also at matters of force and governmentality.     

WAMS-based monitoring and control of Hopf bifurcations in multi-machine power systems

A method is proposed to monitor and control Hopf bifurcations in multi-machine power systems using the information from wide area measurement systems （WAMSs）. The power method （PM） is adopted to compute the pair of conjugate eigenvalues with the algebraically largest real part and the corresponding eigenvectors of the Jacobian matrix of a power system. The distance between the current equilibrium point and the Hopf bifurcation set can be monitored dynamically by computing the pair of conjugate eigenvalues. When the current equilibrium point is close to the Hopf bifurcation set, the approximate normal vector to the Hopf bifurcation set is computed and used as a direction to regulate control parameters to avoid a Hopf bifurcation in the power system described by differential algebraic equations （DAEs）. The validity of the proposed method is demonstrated by regulating the reactive power loads in a 14-bus power system.     

基于双变流器的电力电子课程创新实验平台设计

针对高校实验室电源或线路容量较小的工况,构建了基于双变流器的电力电子课程创新实验平台,介绍了平台的主电路结构和主要环节的设计原理,并对平台的整流、逆变、能量回馈、无功生成及补偿等多项实验教学功能进行了实验验证。结果表明,该实验平台不仅克服了电源或线路容量有限的缺点,而且丰富了电力电子课程探究性实验的教学内容,可显著提升电力电子课程的实验教学质量。     

关于CCS在DSP平台上的应用和研究

结合电力电子和DSP的发展情况,简述CCS在电力电子以及DSP平台上的发展概括和应用研究,并结合自己的看法进行简单的评述。     

Development of cooperative system bridges

Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.