基于三相二臂逆变器LC式混合型有源电力滤波器

为了治理非线性负载产生的谐波问题,研究了一种简化型LC式混合有源电力滤波器,由三相二臂三电平逆变器串联LC无源滤波器之后并网。构建了简化型LC式混合滤波器的电压电流双环的控制框图。直流侧电压采用均压控制,实现了直流侧电压的平稳和均衡,维持逆变器的稳定、可靠运行;针对电流内环,在分析混合型滤波器结构和数学模型的基础上,推导了逆变器的无差拍控制公式,实现了逆变器输出电流的闭环控制,提高了逆变器的动态补偿性能。最后,仿真和实验结果验证了所提出结构和控制方法的正确性。     

混合级联逆变器在STATCOM中的应用研究

随着多电平逆变器在电力系统无功功率补偿领域的广泛应用,为了对目前应用的静止同步补偿器(STATCOM)进行改进,提出了将2H桥与3H桥混合级联逆变器作为STATCOM的拓扑,运用EPWM进行调制的解决方案.该方案可以省去庞大笨重的变压器,减小功耗,降低榆出谐波含量.文章对基于混合级联逆变器的STATCOM的工作原理进行了分析,在完成理论研究的基础上,利用电力电子仿真软件Simplorer进行了仿真研究,仿真结果表明,混合级联STATCOM具有输出波形质量好,动态响应速度快的优点.     

基于自抗扰技术的并网逆变器电流控制

为解决三相并网逆变器电流控制中网压扰动、变量耦合和模型参数偏差等诸多问题,在控制器设计中引入自抗扰技术.利用扩张状态观测器(ESO)对未知扰动进行估计,可同时补偿这些因素的影响.在分析ESO的误差特性和系统传递函数的基础上,提出了带宽参数的设计准则.通过引入等效增益系数,对比分析了线性/非线性ESO的估计、控制效果.仿真结果表明,所设计的控制器对系统参数变化具有强鲁棒性.最后通过实验进一步证实了ESO对扰动的估计和补偿能力,并给出了电感参数未知时控制增益的整定方法.     

基于混合七电平电压型逆变器的新型6kV变频器

提出了一种基于混合七电平电压型逆变器的6kV变频器。混合七电平逆变器由1个采用10CT的三相中点箝位三电平逆变器和3个采用IGBT的H桥逆变器串联而成，可充分利用IGCT高压大容量及IGBT高速的特点。PWM控制采用基于参考电压分解的多电平直接PWM算法。数字化实现容易。采用了改进的死区效应补偿方法以获得理想的输出波形。研制了1台基于混合七电平逆变器的交流380V变频调速实验样机。实验结果为新型6kV变频器工业装置的研制打下了基础。     

一种新型的基于磁通补偿的并联混合型有源电力滤波器

提出一种基于磁通补偿原理和谐波电流分流技术的新型并联混合型有源电力滤波器,并推导了这一新理论.这种新型滤波器通过拓扑结构的改变,使电网中的谐波电流流入三绕组变压器的两个线圈,在变压器铁芯中产生的谐波磁通部分补偿,未完全补偿的部分由APF产生的谐波电流的磁通进行补偿,最终达到减小APF容量的目的.在此基础上,利用MATLAB对这种新型滤波器的稳态和暂态的特性进行了仿真研究,并与传统并联混合型电力滤波器APF容量的计算比较,证明了该原理的正确性.     

基于级联型逆变器的新型PWM技术研究

级联型H桥多电平逆变器的PWM调制技术一般采用载波移相SPWM技术和错时采样SVPWM.对这两种PWM调制技术进行分析,应用一种新型简化多电平PWM技术,即单元矢量延时叠加PWM(Overlap time staggered PWM,OTS-PWM)技术于级联型H桥多电平逆变器.通过对OTS-SPWM和OTS-SVPWM调制技术的的仿真研究,总结了相应的调制规则.最后通过对OTS-SVPWM技术进行实验研究,验证了方案的实用价值.     

一种基于开关函数的逆变器新型模型

提出了一种基于开关函数的逆变器新型模型 ,分析了其适用条件 ,并分别对该模型进行仿真和实验研究。研究结果表明该模型具有非常快的仿真速度和较高的精度     

Direct power control of a multilevel inverter based active power filter

A cascaded H-bridge multilevel inverter based active power filter with a novel direct power control is proposed in this paper. It can be directly connected to medium/high voltage power line without using the bulky transformer or passive filter. Due to the limited switching frequency (typically below 1 kHz) of high-power solid-state devices (GTO/IGCT), multiple synchronous/stationary reference frame current controllers are reviewed and derived. Based on this, a novel current controller is proposed for harmonic current elimination and system power factor compensation. Furthermore, a synchronous/stationary hybrid structure can be derived with fundamental de-coupling control. The instantaneous reactive power theory and synchronous reference frame based control are compared based on mathematical models. A direct power control concept is then derived and proposed. It is equivalent as the hybrid synchronous/stationary frame current controller, but has a simpler implementation. It has clear physical meaning and can be considered as a simplified version of the hybrid frame current controller. Simulations on a 4160 V/1.2 MVA system and experimental results on a 208 V/6 kVA laboratory prototype are presented to validate the proposed active power filter design.     

新型混合式有源电力滤波器的控制方法

由于电力系统中使用了越来越多的电子设备,改善功率因数和消除电网侧的谐波电流便成为很重要的问题,为此,介绍了一种混合式电力补偿器（HPC）的自抗扰（ADRC）控制方法,该方法可以有效地改善功率因数和消除谐波——将消除谐波问题转化成系统跟踪给定相位正弦信号问题,利用扩展状态观测器（ESO）估计干扰,并进行补偿,利用非线性状态误差反馈器（NLSEF）实现参考信号的跟踪。这种控制策略的一个显著特点是不需要精确地测量谐波。基于这种控制方法的混合式电力补偿器对于不同的典型负载、负荷侧电流大小和相位的变化都有很强的适应性。最后,通过对不同负载情况进行仿真,结果证明了这种控制方法的有效性。     

混合级联多电平逆变器的改进混合调制技术

针对于Ⅲ型混合级联型多电平逆变器调制中,逆变器输出的相电压及线电压包含低频次谐波,以及大调制度下出现的超调问题,提出了一种改进的混合调制策略。该策略通过调制波和一对三角载对高压单元进行调制,得到高压单元输出的PWM波,再利用调制波与高压单元输出的PWM波的差值作为低压单元的调制波对低压单元进行调制,得到低压单元输出的PWM波。仿真与实验结果表明该策略能够消除Ⅲ逆变器输出相电压及线电压中的5次和7次低频谐波和超调现象,逆变器输出的相电压和线电压的总谐波失真(total harmonic elimination,THD)分别为14.53%和12.47%,频谱含量主要分布在2mf两侧。     

混合级联型多电平逆变器的研究

提出了一种混合级联型多电平逆变器拓扑结构,给出了逆变器的控制方案。仿真结果表明,逆变器能够以较低的开关频率输出接近于正弦波的电压且只有很低的共模电压。     

一种新型移相级联式高压变频器

采用HV-IGBT元件、作桥级联式的电平逆变技术多重化输出和模块化设计的移相级联式高压变频器．具有结构简洁．安全可靠、无谐波污染等特点．详细介绍了其结构和特点。经试验和实际应用证明．这种高压变频器所用功率器件少．负荷均衡．输入输出线性度好．具有良好的控制特性。     

一种新型移相级联式高压变频器

介绍Diamond-HV移相级联式高压变频器的原理、结构、控制策略、技术性能及现场应用结果。这种高压变频器设计新颖、独特，功率器件少、结构简洁，可靠性高，负荷均衡、线性度好，具有良好的控制特性。移相变压器副边绕组少、制作简单。多电平逆变器能产生多阶梯、低失真电压波形，特别适合于大功率高电压场合。Diamond-HV系列高压变频器输入输出谐波含量低、du／dt小，可直接驱动普通异步电动机．     

基于单周控制的三相三线串联混合型有源电力滤波器

介绍了一种基于单周控制的三相三线串联混合型有源电力滤波器.该滤波器只需检测三相电网电流、负载电压和直流侧电容电压,不需要乘法器,省去了谐波和无功电流的计算.整个控制器只需几个带复位的积分器、比较器、触发器和一些线性元件组成,控制器结构简单.并且具有较强的鲁棒性和较高的可靠性.在建立数学模型的基础上采用Saber仿真软件进行了仿真研究.仿真结果表明基于单周控制的三相三线串联混合型有源电力滤波器能够对系统谐波、无功电流进行有效的补偿,并且具有响应速度快的特点.     

采用垂直多载波调制技术的并网逆变器

在电压源型PWM并网逆变器的设计时,通常用设置开关延时(死区)的方法来避免直流链的短路现象.这种方法将会降低并网逆变器的输出性能,即产生“死区效应”.为解决上述问题,提出一种基于垂直分层多载波的新型复合功能PWM调制策略.与传统的分别进行死区时间设置和基于电压伏秒平衡的死区补偿方法相比,垂直分层多载波PWM调制策略具有...     

A new medium-voltage PWM inverter topology for adjustable-speeddrives

In this paper, a new pulsewidth modulation (PWM) inverter topology suitable for medium-voltage (2300/4160 V) adjustable-speed drive systems is proposed. The modular inverter topology is derived by combining three standard three-phase inverter modules and a 0.33-pu output transformer. The output voltage is high-quality multistep PWM with low dv/dt. Further, the approach also guarantees balanced operation and 100% utilization of each three-phase inverter module over the entire speed range. These features enable the proposed topology to be suitable for powering constant-torque, as well as variable-torque type loads. Clean power utility interface of the proposed inverter system can be achieved via an 18-pulse input transformer. Analysis, simulation and experimental results are shown to validate the concepts     

基于TMS320F2812芯片的并联有源滤波器研究

有源电力滤波器(APF)是近年来提出的一种新型的谐波及无功动态补偿装置,与传统的无源LC滤波器相比较,具有响应速度快、补偿效果好和能够实现动态补偿的优点。数字信号处理器DSP芯片因为具有信号处理快速性特点,所以非常适合于有源滤波器的控制。经过综合归纳分析,对基于DSP处理器TMS320F2812的有源滤波器的硬件电路与软件流程做出了整体设计。     

CVCF inverter based on nonlinear control of instantaneous active and reactive power and its operation characteristics

This paper describes a direct‐power‐controlled CVCF inverter and presents its experimentally examined operation characteristics. The most important feature of this strategy is the direct selection of the switching states of the CVCF inverter to restrict errors between the feedback and command values of active and reactive power. In addition, this paper presents a theoretical analysis of the relationship between the instantaneous power and the switching state, which is essential for deriving a switching‐state table for the controller. The feasibility of the proposed method was verified through several computer simulations and experimental tests using a 2.0‐kVA prototype setup. The output voltages were confirmed to be stable sinusoidal waveforms with a total harmonic distortion of 1.13% under nonlinear load conditions. Excellent voltage balance was achieved by the proposed strategy even under unbalanced load conditions. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(3): 62–69, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21023     

A zero-current-switching based three-phase pulse width modulation inverter

With the remarkable progress of switching devices, the switching frequency of a voltage-source PWM inverter has become higher and higher. A high-frequency PWM inverter gives great benefits in the reduction of current ripples and acoustic noises. However, high-frequency hard switching causes the increase of switching losses and EMI to be solved. The authors propose a zero-current-switching based three-phase PWM inverter which has small resonant circuits on the ac side. The current flowing in a switching device is a sum of the resonant current and the load current. Since the switching device is turned on and off at zero current, the switching losses and electromagnetic noises are greatly reduced. This paper described the principle of the zero current switching operation, the design of the resonant circuits and the control scheme for the new soft switching inverter. Moreover, it shows interesting experimental results obtained by the zero-current-switching PWM inverter which drives an induction motor of 2.2 kW.