基于正负序分离的锁相环

为克服传统软件锁相环(SPLL)在三相不平衡电压条件下,由于负序分量作用导致输出误差角包含的谐波信号,文章提出了对三相电压进行正序负序分离,采用闭环反馈方法,用解耦的方式除去负序分量对输出相位的干扰。通过MATLAB仿真建立锁相环模型,对提出的控制方法在三相不平衡条件下进行了验证,结果表明,该SPLL系统的动态性能、稳态性能比较好。     

三相三线制有源电力滤波器谐波检测方法

针对三相三线制有源电力滤波器(Active Power Filter,APF)中的谐波检测,研究了基于瞬时无功理论的谐波电流快速检测算法,结合谐波检测过程中出现的频率混叠现象而搭建的二阶巴特沃斯低通滤波器,共同实现了有源电力滤波器高精度的谐波检测功能.实验结果验证了方法的正确性和可靠性,对于提高APF的补偿性能有很大的帮助.     

基于瞬时无功功率理论和模糊PID控制的三相不平衡补偿算法

为满足三相不平衡飞机电网的无功功率实时补偿要求,设计了一种新型的静止无功补偿器(SVC)控制系统。该系统采用瞬时无功功率理论来精确检测基波正序和负序电压、电流,并推导出补偿导纳的表达式;SVC的整体控制采用了开环和闭环控制相结合的控制算法,并在闭环控制算法中,提出了自适应非线性模糊控制器在无功补偿控制系统中的应用方案。该方案结合了模糊控制和PID控制2种方法的优点,根据系统状况改变PID控制器的参数,以达到更好的动态控制效果。仿真研究结果表明,该新型SVC控制系统对于提高功率因数和补偿三相不平衡,具有响应快、精度高的控制效果。     

基于改进型p-q算法的10KV电能质量控制装置

针对目前的一些算法在10KV电能质量控制系统中存在的一些缺陷,本文提出了一种新型的改进型P—q算法。它能实时滤除出不对称三相电路电流中的基波电流含量,对基波电流进行坐标变换后就可以快速得到有源滤波器所需补偿的谐波和无功电流量。该算法可以直接用于三相三线或三相四线系统的综合补偿。理论的推导和仿真结果证明了所提方法的正确性。     

电网谐波条件下光伏空调系统控制策略研究

电网电压中通常含有一定分量的谐波,会导致网侧电流出现谐波分量而发生畸变,网侧电压谐波分量和电流的正序分量相互作用还将使网侧变换器输出的有功功率、无功功率产生6倍频波动。为提高光伏空调系统中网侧变换器的运行性能,在电网电压畸变条件下建立网侧变换器正负序分量数学模型,利用以5次和7次谐波电流分量为零的控制方法,实现维持直流母线电压恒定、消除网侧变换器5次和7次谐波电流的控制目标。并基于光伏空调系统仿真平台进行验证,结果及分析表明此控制策略能够有效改善光伏空调系统的网侧电流谐波及系统控制性能。     

三相电能表逆相序检测报警电路

本文提出了一种新型三相电能表逆相序检测报警电路,简单介绍了其工作原理及组成结构,并辅以矢量图着重从理论上对该电路加以证明,当电能表相序接错时报警,以便及时更正接线错误,保证电能表的正确计量.该报警电路结构简单,所用元器件少：由电容、电阻、发光二极管组成,已被试用于某厂三相电度表中,运行结果表明该电路简洁易行,可靠性高,具有较高的实用价值,可广泛应用于逆相序检测系统中.     

三相桥式整流电路谐波电流检测分析与仿真

本文针对电网中最典型的谐波源——三相桥式整流电路,研究基于瞬时无功功率理论的谐波电流检测方法。利用Matlab/Simulink仿真软件,搭建谐波电流检测的仿真模型,进行仿真分析。通过观察得到的仿真波形,验证＂ip-iq＂法在谐波电流检测中的实际效果,从而为治理电网谐波,进行无功补偿,提供简便的分析手段。     

大电机谐波及无功电流检测方法的研究

通过对谐波和无功电流的检测方法种类的比较,提出一种将自适应噪声对消技术用于电机谐波和无功电流检测的新方法.利用神经网络的自学习、自适应能力,解决了检测电路的实时性、精度和误差等问题.     

三相电量在线测试仪的研制

本文介绍的基于双微机控制的三相电量综合在线测试仪能够在不切断被测电路的条件下,综合测量电网的电压、电流、三相功率、电能以及各电量的1～19次谐波分量。     

基于MCU和FPGA双处理器的超音频感应加热电源设计

本文提出一种采用DSP英飞凌XC2267与ALTERA公司的EP2C5T144C8N为双控制核心,主开关器件为IGBT的超音频感应加热电源的设计方案。DSP(xc2267)作为主控芯片进行增量式PI算法,实现了电压电流双闭环控制。提出基于FPGA的相序自适应的三相可控硅整流控制方法;设计一种扫频启动电路,实现由他激到自激启动,实现了高功率和低功率之间的转换。逆变系统采用改进的PWM频率相位锁相和移向调功的复合控制来提高控制精度和效率。最后,通过实验台架对电路进行实验,给出实验结果,验证了整个系统的可行性和有效性。     

Intelligent controlled shunt active power filter for voltage and current harmonic compensation in microgrid system

An integrated microgrid with a novel shunt active power filter (APF) using Elman neural network (ENN) is proposed in this study. The microgrid consists of a storage system, a photovoltaic (PV) system, the shunt APF, a linear load, and a nonlinear load. Moreover, the master/slave control algorithm is adopted in the microgrid. The storage system, which is considered as the master unit, is adopted to control the active and reactive power outputs (P/Q control) in grid-connected mode and the voltage and frequency of the microgrid (V/f control) in islanded mode. Furthermore, the PV system is considered as the slave unit to implement P/Q control in both grid-connected and islanded modes. In addition, the proposed shunt APF possesses dual functions of voltage and current harmonic compensation for microgrid under voltage harmonic propagation and nonlinear load to reduce the voltage and current total harmonic distortions (THD) effectively. Additionally, an ENN controller is adopted in the proposed shunt APF to improve the transient and steady-state responses of DC-link voltage during the switching between the grid-connected mode and islanded mode. Finally, some simulation results are provided to verify the feasibility and the effectiveness of the integrated microgrid with the intelligent controlled shunt APF.     

并网变流器三相谐波检测方法的研究

针对在电力系统中广泛应用的各种变频器、变流器、开关电源和电抗器会使电网中的谐波含量增加带来的诸多影响,该文介绍了并网发电系统中变流器谐波检测的重要性,分析了不同的三相谐波检测技术,并通过谐波检测技术提取并网变流器中电压/电压谐波,从跟踪和提取时变谐波上比较了三相谐波检测技术。     

Instantaneous Sequence-Component Resolution of 3-Phase Variables and Its Application to Dynamic Voltage Restoration

A technique for decomposing instantaneous three-phase voltages and currents into sequence components has been described. The technique is based on a recursive weighted least squares procedure. The main advantage of the proposed technique is the use of the same covariance and gain matrices for resolving any number of three-phase variables into their respective sequence components. The proposed technique also estimates the dc offset in the sensed variable, and these are eliminated during the processing. Finally, the proposed technique has been implemented in a digital signal processor (DSP) and has been applied to the open-loop control of a laboratory-scale dynamic voltage restorer.      

谐波及无功分量实时检测的一种小波方法

从小波函数的带通性质出发,利用小波变换在不同尺度下对非正弦电流信号进行检测,由此得出了它的基波和谐波分量及其有效值. 通过重构基波分量与电源电压之间的相位差,求得了信号中的基波无功电流分量. 为说明所提出检测方法的有效性,进行了相应的仿真研究,并讨论了影响检测精度的因素.     

Current decomposition in asymmetrical, unbalanced three-phasesystems under nonsinusoidal conditions

The most attractive theories found in the literature for the representation of the electrical systems under nonsinusoidal conditions can be divided to a great extent into those operating in the time domain and those operating in the frequency domain. When three-phase systems are concerned, the time-domain approach is mainly due to Akagi and Nabae under the name of “instantaneous power theory” or “p-q theory” and is based on the Park transformation. The frequency-domain approach is mainly due to Czarnecki. At a first reading, these two theories seem to be quite different. This paper shows how the application of some interesting properties of the Park transformation leads to a unified approach to the harmonic and sequence components and hence allows derivation of the frequency-domain current decomposition proposed by Czarnecki in a more straightforward way. Moreover, an extension of this decomposition to the case of asymmetrical supply voltages is considered     

Dynamic voltage restorer based on a four-leg voltage source converter

Analysis and control of a dynamic voltage restorer are described. The voltage restorer is based on a four-leg voltage source converter. The three-phase input variables are resolved into the positive, negative and zero-sequence components using a weighted, recursive, least-squares estimator. Identical controllers have been used for each sequence component. A laboratory model of the restorer has been constructed and its performance has been tested by simulation and experiments.     

谐波噪声下的试验模态分析

试验模态分析中通常使用平均方法处理由实验环境引起的随机噪声。当测试环境中含有周期噪声时,很难通过平均方法去除,在频响函数中会产生虚假共振峰,影响结构参数识别精度。该文提出了基于增强概率统计的谐波响应检测方法,将物理坐标下的响应信号变换到模态坐标中,并根据谐波信号的统计特性检测出谐波成分。提出了一种基于谐波分解与重构的谐波去除方法,用于消除谐波成分对结构参数识别的影响。通过平面刚架的仿真算例和GARTEUR飞机模型实测算例阐明了提出方法的实现过程,验证了其可靠性。