Harmonic Domain Modelling of Space Vector Based STATCOM

This paper presents frequency domain method for harmonic analysis of space vector based STATCOM. Space Vector Pulse Width Modulation (SVPWM) method is an advanced PWM method. It is a best method among all the PWM techniques. It provides a freedom in a switching cycle for placement space vector. In this paper, the SVPWM is used for switching of STATCOM. The harmonic (or frequency) domain is a steady-state form of harmonic analysis method, which represents converters to their harmonic spectra. This paper presents harmonic analysis by means of harmonic domain for space vector based Static shunt converter (STATCOM). Performance of the STATCOM is evaluated in harmonic domain simulation studies in MATLAB environment.

Dynamic Harmonic Domain Modelling of Space Vector Based SSSC

This paper presents analytical frequency domain method for harmonic modeling and evaluation of Space Vector Pulse Width Modulation (SVPWM) based static synchronous series converter (SSSC). SVPWM is the best among all the PWM techniques. It gives a degree of freedom of space vector placement in a switching cycle. Dynamic modeling technique is used for space vector modulation (SVM) based voltage source converter that is adapted as a static synchronous series converter (SSSC) for harmonic analysis using dynamic harmonic domain. Performance of the SSSC is evaluated in dynamic harmonic domain simulation studies in MATLAB environment. The switching function spectra are necessary for harmonic transfer matrix which is calculated using Fourier series. This paper presents the analysis of harmonics for space vector based SSSC during steady state and dynamic condition.

An Improved Hybrid Space Vector PWM Technique for IM Drives

In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) cuddled SVPWM is amalgamating the pre-calculated switching timings for various sections of hexagonal space vector boundary and the random selection of carrier between two triangular signals, in order to disband acoustic switching noise spectrum with improved fundamental component. The arbitrary selection between triangular carriers, which is decided by digital signal states (Low or High) of the linear feedback shift register (LFSR) based pseudo random binary sequence (PRBS) generator. The SVPWM offers a control degree of freedom in terms of positioning of vectors inside every sampling interval and hence it has six possible variants of the voltage vectors arrangements in each sector. The developed HSVPWM is thoroughly analyzed in using the MATLAB? based simulation for all SVPWM variants. From the simulation and experimental results viz. harmonic spectrum, harmonic spread factor (HSF), total harmonic distortion (THD) etc., and the superiority of the proposed scheme such as better utilization of DC bus and the randomization of the harmonic power are evidenced. For the practical implementation, Xilinx XC3S500E FPGA device has been used.

Groove modeling and digital simulation for intersecting structures of circular tubes based on coplanarity of vectors

In order to establish the groove model for intersecting structures of circular tubes,mathematical model of the intersecting line is established by the method of analytic geometry,and parametric equations are thus determined.The dihedral angle,groove angle and actual cutting angle for any position of the intersecting line are derived as well.In order to identify groove vectors for two pipes,a new analytical method,i.e.coplanarity of vectors,is further proposed to complete the groove model.The established model is virtually verified by programming and simulation calculation in the MATLAB environment.The results show that groove vectors of intersecting structures simulated by MATLAB are consistent with the theoretical groove model,indicating that the theoretical groove model established in this paper is accurate,and further proves that the proposed coplanarity of vectors for solving groove vectors is correct and feasible.Finally,a graphical user interface(GUI)is developed by MATLAB software to independently realize functions such as model drawing,variable calculation and data output.The research outcome provides a theoretical foundation for the actual welding of circular intersecting structures,and lays an essential basis for weld bead layout and path planning.

基于dSPACE的新型双滑模PMSM控制方法

设计一种基于滑模理论的永磁同步电机控制系统,利用滑模控制器代替传统的PID控制器,用滑模观测器代替传统的位置传感器。滑模控制器中针对传统滑模控制的抖振问题,引入准滑模和趋近律的概念,设计一种新的滑模控制器。滑模观测器使用连续饱和函数代替传统的开关函数,有效地减少高频噪声信号,经李亚普诺夫稳定方程证明系统的稳定性。本设计方法充分发挥滑模控制的优势。通过d SPACE实验平台的验证和Control Desk环境的实时观测,证明所设计的新的滑模控制器在消除抖振和抗干扰方面明显优于传统的滑模控制器和PID控制器,滑模观测器能准确地观测位置信号,而且针对具有噪声干扰的场合,加入卡尔曼滤波器,有效地减少了干扰信号。

dSPACE电机控制平台设计与SVPWM矢量控制实现

以d SPACE半实物实时仿真系统为基础,利用d SPACE与MATLAB/Simulink可以实现无缝链接的优势,将离线仿真模型通过试验进行快速验证,提高电机控制系统开发效率,缩短项目开发周期。介绍了d SPACE标准组件系统的软硬件环境,完成基于d SPACE电机控制试验平台的设计。最后在此平台上实现永磁同步电机SVPWM矢量控制,验证了d SPACE电机控制试验平台进行控制算法开发的高效性。

基于DSP与基于dSPACE生成SVPWM波的比较研究

通过比较基于DSP与基于dSPACE生成SVPWM波为例,介绍了基于dSPACE的半实物仿真技术。实验证明dSPACE实时仿真平台具有良好的控制效果,从而显示了dSPACE实时仿真平台与传统开发工具相比有其自身的特点和优势,可成为开发系统或是控制器的又一选择。

基于谐波状态空间模型的MMC解析仿真方法

随着输送电压等级的提升和模块化多电平换流器(modular multilevel converter,MMC)子模块数量的增加,基于详细模型的MMC的仿真方法已难以应对子模块数量增长带来的计算效率上挑战。对此,文中提出一种基于谐波状态空间法的MMC解析建模仿真方法,在能够独立地提供各阶次谐波的暂态波形的同时,实现了大步长仿真。首先,建立考虑交直流侧耦合的MMC在时域下的状态方程,之后通过谐波状态空间法将其转换至谐波域,并推导出其开环控制下的阶跃响应解析式;然后,基于该解析式提出仿真全过程的迭代公式及其数值算法;最后,通过仿真算例验证所提方法的有效性。

基于复矢量及HSS的MMC交直流侧阻抗建模

模块化多电平换流器(modular multilevel converter,MMC)具有运行稳定、控制多样化等优点,对其精确建模成为当前研究热点。提出了一种基于复矢量的MMC交直流侧阻抗建模方法。该方法根据复矢量建模的基本原理分析了换流器的正负序转换关系,并在考虑三相耦合的前提下,从差共模角度简述了三相MMC的建模要点,建立了三相系统的完整时域模型。引入谐波状态空间理论(harmonic state space,HSS)对所建模型进行处理来提高建模精度,并利用接口矩阵及阻抗求解的基本原理建立了MMC的交直流侧阻抗模型。最后在仿真平台进行了对比实验,证实了建模方法的可行性。

六相全桥逆变器驱动PMSM的简化模型预测电流控制

全桥逆变器电机驱动或称开绕组结构虽然兼具相间电气隔离、容错性能好及器件开关频率低等优点,但存在逆变器输出电压矢量多、冗余严重且控制约束等问题。文中以共直流母线供电的六相全桥逆变器驱动六相永磁同步电机为研究对象,提出了一种基于二级矢量优化的简化模型预测电流控制算法,在实现电机定子基波电流有效跟踪控制的同时有效抑制了定子电流的谐波及零序分量。文中基于矢量空间解耦理论对六相全桥逆变器的输出电压矢量进行了分层分析,以定子基波电流控制、谐波及零序电流抑制为准则对逆变器输出的729个电压矢量进行二级优化,得到候选的12个电压矢量,以此为基础设计了模型预测电流控制算法。实验结果表明,该简化模型预测电流控制方法具有良好的动静态性能,能在基波电流控制的同时有效抑制谐波及零序电流分量,可为多相电机驱动系统研究提供一定的理论支撑。

应用两种旋转矢量法研究平面简谐波

如何正确应用振动旋转矢量和空间(波动)旋转矢量研究平面简谐波的问题,是大学物理教学中的一个重点问题.在系统对比分析两种旋转矢量的基础上,从波函数和波形图两方面比较分析了两种旋转矢量在描述平面简谐波上的异同,归纳了应用两种旋转矢量解决平面简谐波问题时应注意的问题.结果表明,应用两种旋转矢量都能较大程度地降低分析解决平面简谐波问题的难度.在应用时,应说明旋转矢量的类型和注意其特征,避免混淆出错.

A New Control Approach of a Three-Phase Inverter Two Levels

In this paper, we present the study, modelling and simulation of the duty cycle modulation (DCM) based on SVPWM control technique using Matlab/Simulink software. It is one of the most advanced control techniques of space vector modulation (SVM), which can be used for controlling static converters or for controlling electrical machines to achieve better dynamic performance. DCSVM is a control technique that generates control signals for the two-level voltage converter as well as for the intermediate times. The main advantage of this control technique is the reduction of the number of calculations, especially for the trigonometric functions and the generation of the reference voltage. In order to reduce the computational effort, we have designed a DCSVM controller that is able to faithfully reproduce the same vectors and output quantities as a classical SVM. In order to test the functionality and validity of the DCSVM control, we have developed different simulations that result in a total harmonic distortion (THD) of the voltage and current of 41.19% and 15.19% respectively with fundamental values of 61.51 V for the voltage and 2.80 A for the current;in contrast to the SVM which gives 47.27 V for the voltage and 2.01 A for the current with THDs of 77.16% for the voltage and 16.00% for the current. This results in an improvement in the distortion rate of around 25.5%. The results obtained are very satisfactory. The DCSVM is a real competitor to the SVM and its various variants.

基于空间矢量的基波正序、负序分量及谐波分量的实时检测方法

提出了一种新的实时检测基波正序分量、基波负序分量和谐波分量的方法 ,该方法首先将三相瞬时值合成一个空间矢量 ,然后对所得矢量的实部和虚部分别进行滤波以滤去谐波分量。如果忽略滤波后残余的谐波分量 ,则滤波后的矢量可认为是由对应正序分量的逆时针方向旋转的矢量和对应负序分量的顺时针方向旋转的矢量合成。实时分解这两个矢量的方法为 :将分解后的两个矢量根据所用滤波器的特性旋转一个适当的角度 ,可以完全补偿滤波所引起的相移 ,从而可以实时准确地分解出基波正序分量和基波负序分量 ,进而分解出谐波分量。仿真结果证明了所提方法的正确性和有效性。

基于MATLAB的矩阵变换器空间相量调制研究

矩阵式变换器是一种具有优良输入输出特性的新型交- 交直接电源变换器。对矩阵变换器进行了建模和运行分析 ,推导出矩阵式变换器和等效交 - 直- 交结构的开关函数关系 ,从而由等效交- 直 - 交结构的双空间矢量控制规律得到交- 交直接变换的空间相量控制策略。并进行了 MATLAB仿真 ,仿真结果证明矩阵变换器空间相量调制策略的正确性、优越性。

空间矢量调制的矩阵式变换器仿真模型研究

该文用Matlab Simulink 建立了空间矢量调制的矩阵变换器的2个仿真模型,1个简化模型,1个复杂模型。简化模型中,开关矩阵由9个理想开关组成, 不考虑任何换流引起的短路问题。在用于验证控制策略改进方法,试验外围电路参数及模型中模块的正确性时,简化模型可代替复杂模型。复杂模型主要用于模拟实际系统,用于检验在简化模型下已验证的策略或参数在实际条件下的工作情况。2个仿真模型的结果证明:矩阵式变换器的简化模型在验证功能上和实际模型能达到同样的效果,并能大大提高工作效率。2个仿真模型为矩阵变换器软、硬件的研究和调试带来极大方便。

空间矢量调制的矩阵式变换器的仿真模型

详细介绍了用MATLABSIMULINK软件包建立的空间矢量调制的三相交 -交矩阵式变换器的仿真模型 ,给出了主要仿真波形 .仿真结果证明了控制策略的正确性 .

空间矢量PWM波形的谐波仿真研究

本文基于空间矢量调制的工作机理，研究了４种逼近方式并得到４种空间矢量ＰＷＭ（ＳＶＰＷＭ）波形。通过分析、仿真，研究了它们的谐波成分和开关频率，得出不同逼近方式的优缺点。

高压直流输电电压源换流器的等效模型及混合仿真技术

文章提出了混合仿真的概念和实现以及高压直流输电电压源换流站(Voltage source converter based HVDC,HVDC-VSC)的等效仿真模型,该模型忽略了VSC的开关纹波。采用混合仿真技术和等效仿真模型既能提高仿真速度又能很好地反映HVDC-VSC的动态特性。文章提供的仿真结果证明了HVDC-VSC的等效仿真模型和混合仿真技术的有效性。

矩阵式电力变换器的控制策略综述

对矩阵式电力变换器的几种控制策略进行了比较,分析了直接变换法、间接变换法和滞环电流踉踪法的基本原理和电压传输比。把矩阵变换器等效成一个虚拟的整流器和一个虚拟的逆变器,以虚拟逆变器为例,介绍了电压空间矢量脉宽调制(VSVPWM)技术的控制策略,并进一步探讨了实现这些控制策略的安全换流问题、开关损耗问题和谐波抑制问题。

基于瞬时电压矢量定向的有源电力滤波器补偿电流检测

结合电力系统无功补偿与谐波治理的基本原则,对基于瞬时无功功率理论的传统谐波电流检测方法在有源电力滤波器中的应用进行了简要分析,进而提出了以电网电压为参考基准,以实现各种非线性负载及阻感、阻容性负载向纯电阻性负载转换为目的的负载电流波形和相位治理原则,并详细阐述了基于瞬时电压矢量定向的补偿电流检测方法。该方法克服了传统方法在电网电压畸变时补偿后电流不能跟随电网电压波形的不足,避免了有源电力滤波器补偿电流过大及畸变无功功率倒送电网现象的出现,同时该方法具有频率自动跟踪、相序自适应等特点。最后,通过仿真和样机试验验证了该补偿电流检测方法的优越性。