梯形脉宽调制型逆变器的单片机控制

本文提出了用梯形脉宽调制（ＴＰＷＭ）降低逆变器谐波的一种新方法。在逆变器中，较正弦脉宽调制（ＳＰＷＭ）方法它体现优越的谐波控制性能。对梯形调制信号的三相ＰＷＭ逆变器输出波形从理论和实验两个方面作了研究。     

变频调速电压同步SVPWM波生成方法仿真分析

分析了可用于大功率牵引传动领域的空间电压矢量同步脉宽调制的实现原理,给出了牵引逆变器输出电压波形满足同步、三相对称、半波对称的条件.同时得到了在开环变频调速过程中,采用同步SVPWM控制时,逆变器输出电压电流仿真波形,并对其进行了谐波特性分析.仿真结果证明了采用同步空间矢量脉冲宽度调制的一系列优点.     

一种消除窄脉冲的三电平粒子群优化PWM方法

以应用于大功率电力机车的三电平逆变器为特定的研究对象,对优化脉宽调制(PWM)技术的求解与应用进行了分析和研究。针对优化PWM的脉冲序列在调制度较大时可能出现窄脉冲的问题,此处提出了一种简单且有效的窄脉冲消除方法。建立了三电平牵引逆变器优化PWM方法的数学模型,在应用粒子群优化(PSO)算法求解模型时,施加了窄脉冲消除算法以消除窄脉冲。通过仿真和半实物实验验证了所提出窄脉冲消除方法的有效性及PSO-PWM的谐波优化作用。     

优化开关模式单相SVPWM与载波PWM统一性研究

针对单相脉宽调制(PWM)逆变器,在分析单相电压空间矢量脉宽调制(SVPWM)基本原理的基础上,给出了一种优化开关模式单相SVPWM的DSP实现方法。该模式有效避免了PWM周期间和逆变电压扇区间的电压矢量突变问题,降低了逆变开关损耗,且逆变输出波形谐波含量低。通过分析推导优化开关模式单相SVPWM的载波调制形式及其零序信号形式,论证了优化开关模式单相SVPWM与载波PWM的统一,实验结果验证了分析的正确性。     

基于SHEPWM的级联五电平高频逆变器

高频逆变输出如超声换能器等应用场合,由于输出频率高,采用传统的正弦脉宽调制(SPWM)方式对开关频率的要求极高,单纯通过提高开关频率难以满足输出谐波要求.多电平技术可在低开关频率下获得更好的输出波形,在此将特定谐波消除脉宽调制(SHEPWM)技术应用到级联型高频逆变器的控制中.针对两路级联(五电平)电压型逆变器,提出一种计算相对简单的特定谐波消除模型,称为镜像剩余谐波消除模型.该模型分别对两路级联逆变器单元的输出谐波进行建模,利用第2路逆变器中的谐波作为第1路逆变器谐波的镜像谐波,实现谐波消除.通过仿真和实验验证了该模型的谐波消除效果.结果表明所提模型能够较好地实现特定谐波的消除,相比直接法多电平SHEPWM谐波消除方法具有建模简单、计算方便的优点.     

基于随机脉宽调制技术简化中频电源输出滤波器

在分析逆变器控制模型的基础上,将单极倍频和随机脉宽调制技术用于逆变器波形调制,有效提高逆变器等效开关频率,并明显降低开关频率处的离散谐波幅值.分析了随机信号对开关函数功率谱密度特性的影响,据此提出随机脉宽调制技术的实用化设计方法.改进后逆变器输出滤波器的截止频率可以取较高值,保证足够的控制系统带宽,有效提高逆变器输出电...     

一种PWM结合移相控制的低开关频率逆变器

阶梯波合成逆变器具有开关频率低和输出电压波形质量好等优点,但输出电压调节困难,限制了其应用场合,且由于其移相变压器设计和加工复杂性,通道数一般在4以下,这使得输出电压波形质量难以进一步提高。提出一种脉宽调制(pulse width modulation,PWM)和移相控制相结合的低开关频率逆变器,采用多组结构相同的阶梯波合成逆变器,错相叠加每组逆变器PWM波形,使输出电压谐波达到接近无谐波程度。实验表明,所提出的逆变器具有良好的输出特性和调节性能,在大功率变流场合具有很好的应用价值。     

谐波电流最小同步优化脉宽调制策略研究EI北大核心CSCD

在许多大功率交流传动领域,由于开关损耗较大,功率半导体器件的开关频率不能过高,通常在1 kH z以下,逆变器工作在较低的载频比下,因此对逆变器相电流谐波抑制就变得十分紧迫。为达到相电流谐波最优化的目的,需要依靠一定的数学约束条件对调制波形进行精确控制,因此可编程优化调制策略得到广泛应用。其中将谐波电流最小作为约束条件的优化脉宽调制(pulse width modulation,PWM)是一种非常具有吸引力的解决方案。该文以谐波抑制能力较弱的两电平三相三桥臂电压型逆变器为研究对象,给出使得输出电流谐波最小的优化脉宽调制较为精确的约束条件,并且完成全调制范围、多种波形发生条件下的优化函数多解的比较,并最终给出最优的优化开关角组合。比较该调制技术与其他传统的脉宽调制技术在谐波抑制能力方面的性能,并经过仿真与实验进行验证。     

轨道交通牵引逆变器调制策略性能比较

在大功率电力机车以及高速动车组牵引传动系统中，由于受到散热条件等因素的限制，牵引逆变器的最高开关频率通常受到严格限制，导致逆变器输出电压含有大量谐波，进而影响系统效率，并恶化系统控制性能。基于对大功率牵引传动系统脉宽调制策略现状的分析，梳理并分析当前针对低开关频率下不同脉宽调制策略的评价指标。对当前牵引传动系统中应用较多的主流调制策略从加权总谐波畸变，定子谐波磁链，电机转矩脉动等不同角度进行详细的分析对比。分析结果可以为实际牵引传动系统多模式调制策略的优化设计提供参考依据。     

具有低开关频率特性的指定谐波抑制预测控制方法研究

为了避免器输出波形中低次谐波对孤岛型微电网的电压质量产生严重影响,需尽可能减少其谐波失真含量。同时,为提高逆变效率,还需降低开关损耗,令逆变器保持在低开关频率的工况下。模型预测控制相较于脉宽调制策略的灵活性更高,动态性能更好,常与其他优化算法结合,以获得所需控制效果。因此,该文提出一种具有低开关频率特性的预测控制指定谐波抑制开关策略,采用该策略可以减少输出电压信号低次谐波含量,有效抑制谐波畸变,同时可以有效降低系统的开关频率。针对未来时刻电压状态谐波提取相互独立的特点,将并行计算方法的思想引入预测控制中,提高系统的在线实时性。在两电平逆变器实验平台上进行测试,验证了该方法的正确性以及控制策略的有效性。相比指定谐波消除脉宽调制策略,所提方法能在线实时生成稳定的逆变器开关序列,证明了该控制策略不仅能在低开关频率工况下有效抑制低次谐波,而且具有良好的动态性能。     

基于分子动理论算法的三电平逆变器谐波优化

在许多大功率交流传动场合下,开关损耗大。为了降低开关损耗,提高逆变器效率,开关频率一般限制在1 kHz以下,导致牵引逆变器中含有大量的谐波。以应用于大功率电力机车的三电平逆变器为特定的研究对象,建立了三电平逆变器最小相电流总谐波畸变率谐波优化模型。采用分子动理论优化算法求解模型时施加了消除窄脉冲算法,完成全调制范围、多种脉波条件下优化函数的求解。与传统SPWM和SHEPWM比较,MMTPWM具有良好的谐波优化效果。最后,通过仿真实验和硬件实验结果验证了理论分析的正确性。     

基于电流谐波优化的混合脉宽调制策略

受轨道车辆牵引功率大、开关频率低的限制,牵引传动系统多采用低频区异步调制,基频以上单脉冲调制的脉宽调制方式,且在中频过渡区通常需采用优化同步调制以达到改善变流器输出特性的目的。电流谐波最小脉宽调制技术(CHMPWM)是优化同步调制的一种,它以电机电流谐波整体最优为目标进行调制,有助于高性能电流闭环控制的实现,近年来受到广泛关注。对基于电流谐波优化的混合脉宽调制策略展开研究,首先分析CHMPWM的开关角求解方法及不同开关角分布方式对其性能的影响,并从电流谐波、转矩脉动等方面与特定谐波消除脉宽调制技术(SHEPWM)进行对比;然后完成基于现场可编程门阵列(FPGA)构架的混合脉宽调制技术,并实现不同调制模式间的平滑过渡。最后对所提方法进行仿真和实验验证。     

Optimal pulse patterns of a nine-phase voltage source PWM inverter for use with a triple three-phase wound ac motor

The authors have already described the nine-phase inverter driving system providing both the triple three-phase voltage source inverter with 180-deg conducting period and the ac motor windings with triple three-phase construction. The nine-pulse inverter driving system used three small-capacity three-phase coupling reactors having special windings for current balance and reduction of higher harmonics. In addition, for voltage control, current balance, and waveform improvement, optimal PWM pulse patterns were applied to the six-phase inverter driving system using a three-phase coupling reactor to provide double three-phase construction. In the system based on the mode in the title, the PWM control was applied to the nine-phase inverter driving system described in the foregoing. The coupling reactors in the system balance the fundamental currents of three sets of three-phase inverters and also absorb higher harmonic voltages other than 18p±1 (p = 1, 2, …) orders. The optimal pulse patterns found by the approach to make the performance index minimum using the Lagrange multiplier method can be applied to the PWM to reduce the higher harmonic currents greater than those calculated by the modulation method comparing the sinusoidal signal wave with triangular carrier signal. This system can have a larger capacity than the six-phase PWM inverter driving system in which coupling reactors absorb higher harmonic voltages other than the 12p±1 orders and also improve output current waveforms. In addition, the system includes the capacity of coupling reactors slightly larger than the six-phase PWM inverter driving system but enables operation with smaller torque ripples and electromagnetic noises in low- to high-frequency ranges.     

Harmonic analysis of the output voltage of a third‐harmonic‐injected inverter for LSM drives

The superconducting magnetic leviation railway system (MAGLEV) under development in Japan uses pulse‐width‐modulation (PWM) inverter for driving a linear synchronous motor (LSM). The inverter output voltage contains nonnegligible harmonics which cause harmonic resonances in the LSM system, and therefore harmonics of the output voltage have been analyzed in order to control such harmonic resonances. This paper applies a third‐harmonic injection method to the inverter for the purpose of enhancing the output voltage without changing the circuit configuration. It performs harmonic analysis of the output voltage of the inverter based on the third‐harmonic injection. Validity of the harmonic analysis is verified by computer simulation. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 71–78, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ).     

多单元串联多电平逆变电源的控制方法研究

分析了多单元串联大功率逆变电源的控制原理；提出了单个功率单元的二重化控制技术与水平移相式PWM技术相结合的控制方法，从而大大降低了开关损耗，改善了输出波形，减小了输出电压的谐波畸变率；同时，对所研究的控制方法进行了仿真，并通过硬件实验进一步验证了控制原理及仿真结果的正确性。     

Analysis of PWM GTO Current Source Inverter-Fed Induction Motor Drive System

A GTO current source inverter which consists of six main GTO's, two auxiliary GTO's, and three capacitors is presented. This inverter can supply both the sinusoidal voltage and current to the motor by pulsewidth modulation (PWM) techniques. The normal PWM pattern produced by two control signals with the carrier and the modulating waves and the optimal PWM pattern determined by the harmonic analysis are described. The experimental waveforms for 2.2-kW induction motor drives are given and the circuit operation of this inverter in the PWM technique is clearly shown. In addition, the steady-state characteristics of this inverter-induction motor drive system are analyzed by the state-variable methods, and a close agreement between the analyzed and the experimental waveforms is obtained. It is shown that the harmonic components are eliminated or reduced by using the optimal PWM pattern, and the new inverter with sinusoidal current and voltage is very excellent for ac motor drive.     

一种新型电压型逆变器拓扑结构及其PWM控制方法

多电平逆变器具有功率容量大、输出谐波小、传输损耗低等优点而得到越来越广泛的应用.其主要缺点是电路结构复杂、需要大量的功率元件、控制方法复杂.在传统H桥级联型逆变器基础上,提出了一种新型逆变器拓扑结构.通过采用辅助双向开关,在提高输出电压电平数的同时大量减少功率开关元件的数量,简化了电路结构.并根据新型逆变器拓扑结构的特点,提出了一种阶梯波PWM控制方法,采用特定谐波消除法(SHE-PWM)对逆变器输出电压的低次谐波进行抑制,同时进行了仿真.最后建立一套九电平电压型逆变器试验系统,对拓扑结构和PWM控制方法进行了验证.     

Basic Study on Loss Factor Evaluation of Concentrated Winding Permanent Magnet Synchronous Motor

This paper describes the influence of pulse width modulation (PWM) inverter harmonic loss on concentrated winding interior permanent magnet synchronous motor characteristics by using finite element method (FEM) analysis and several measurements. In the measurements, the PWM inverter harmonic loss was evaluated by using a PWM inverter and a sinusoidal power supply. By using the FEM analysis, it was confirmed that the PWM inverter harmonic mainly caused an increase of eddy current losses in the magnetic steel sheet and the permanent magnet. The results indicate that higher inductance of the motor is effective in reducing the harmful effects of PWM inverter harmonics.     

一种带储能的级联光伏逆变器的协同调制方法

提出一种带有储能的混合级联光伏逆变器结构,并针对该逆变器的结构和工作原理,提出基于特定谐波消去(SHE)与载波移相(PS-PWM)调制的协同调制方法。该逆变器将1个储能单元与数个光伏单元混合级联,储能单元使用SHE消除其输出电压中的部分低次谐波,光伏单元采用PS-PWM技术补偿储能单元输出中未被消除的低次谐波,从而进一步降低总的输出电压中谐波含量。仿真结果表明,对于储能单元与光伏单元的输出电压幅值和相位不同的情况,相比于采用单一的PS-PWM调制,采用协同调制方法的输出电压中低次谐波含量与总谐波失真(THD)均较低。     

DIGITAL SIGNAL PROCESSOR BASED VOLTAGE FED INSULATED GATE BIPOLAR TRANSISTOR INVERTER DESIGN

ABSTRACT

A Digital Signal Processor (DSP) based voltage-fed Insulated Gate Bipolar Transistor (IGBT) inverter that drives a three-phase induction motor is presented. The selected DSP, a TMS320C14 chip by Texas Instruments, controls the PWM operation of the inverter. A host IBM PC is connected to the DSP through an RS-232 serial interface for data communications to and from the DSP. IGBTs are used in the inverter because of their characteristically low conduction losses, small switching delays and simplified gate drive circuit. A harmonic elimination scheme is adopted as the PWM strategy to eliminate four low-order harmonics in the inverter output.

The inverter performance is tested using a 1 HP, three-phase induction motor. The output waveforms are recorded and the harmonic spectra are developed using a FLUKE 41 power harmonics analyzer and the results show decidedly suppressed low-order harmonics. The design also highlights the simplicity and cost effectiveness of the DSP based modulator and IGBT based inverter design.