双三相永磁同步电机全调制比范围空间矢量脉宽调制

针对六相电压源逆变器供电的相移30°双三相电机,为提高母线电压利用率,并减小系统损耗和转矩脉动,提出一种新型的全调制比范围空间矢量脉宽调制(SVPWM)策略。该策略根据基波调制系数,将调制区域分为线性调制区和过调制区,在线性调制区将正弦调制区和非正弦调制区的调制算法统一为基于中间矢量算法,该算法计算简单且大幅度的减少在非正弦调制区所注入的6k±1(k=1,3,5,…)次谐波。在过调制区将三相过调制算法推广到六相系统并进行改进,过调制Ⅰ区通过算法改进使参考电压矢量幅值与调制系数成线性关系便于算法的实现;过调制Ⅱ区通过对相位进行修正,减小了相电压的畸变。仿真分析和实验结果验证了算法的有效性和可行性。     

五相电压源逆变器的空间矢量脉宽调制方法研究

为提高五相电压源逆变器(voltage source inverter,VSI)的直流母线电压利用率,减少输出相电压中所含的谐波分量,提出一种改进的基于最近四矢量的五相VSI空间矢量脉宽调制算法。根据调制系数的不同,将整个调制范围分为正弦调制区和非正弦调制区。在正弦调制区,通过合理分配空间矢量的作用时间,使得输出相电压为标准正弦波形,不含有任何谐波成分;在非正弦调制区,通过对谐波子空间内的电压矢量进行优化控制,在进一步提高直流母线电压利用率的同时,保证输出相电压中所含谐波分量更少,使逆变器工作在最优状态。仿真和实验结果验证了所提算法的正确性和可行性。     

基于矢量分解和叠加原理的双三相感应电机在全调制比范围内的PWM策略

对于六桥臂电压源型逆变器供电的双定子绕组异步感应电机,为提高逆变器直流母线电压利用率,并抑制电流谐波,提出一种新的脉宽调制(pulse width modulation,PWM)算法。该方法利用空间矢量分解的原理,在低次谐波被消除的基波空间计算参考电压矢量,并在过调制区通过叠加原理选择合适的开关状态矢量重构参考电压矢量,从而实现从线性调制到方波控制的平滑过渡。详细介绍该调制算法的基本原理,并进行实验。研究结果表明,该算法下的输出基波电压幅值与调制比呈线性关系,且定子绕组电流谐波含量也得到了明显抑制。     

五相电压源逆变器最近四矢量最小谐波电压调制方法

为了优化五相电压源逆变器(voltage source inverter,VSI)空间矢量调制的输出电压,降低输出电压的谐波分量,减少在五相电机所产生的谐波电流,降低电机运行噪声,提出一种谐波电压最小的最近四矢量五相空间矢量调制算法。通过引入合成基本矢量的方法,在三次谐波子平面对谐波电压进行数学分析,得到了最小谐波电压的调制算法。在最近四矢量的正弦调制区,选取合适的合成基本矢量,可使相电压谐波成分抑制为零;在非正弦过调制区,通过谐波最优解来求出空间矢量所在扇区的两合成基本矢量的大小,实现最小谐波的空间调制算法。通过仿真和实验,同两矢量和改进四矢量调制算法进行比较,仿真和实验结果验证了所提出方法的正确性和可行性。     

一种SVPWM过调制算法及其在两电平逆变器中的应用

过调制能够有效地提高逆变器的输出基波电压,传统的空间矢量PWM过调制算法需要经过复杂的实时计算或查表,不易于实现。针对此问题,研究一种过调制算法,不需要经过复杂的运算和查表,易于实现,能够使逆变器从线性调制区平滑地过渡到六阶梯波工作区,并且输出电压谐波含量低。在两电平逆变器矢量控制系统上对过调制算法进行了实验。理论分析和实验结果表明该算法具有输出电压谐波含量低和实现简便的优点,适合应用于矢量控制系统中。     

五相逆变器非正弦双随机空间矢量脉宽调制策略

为改善五相逆变器非正弦供电的高频性能,提出一种五相空间矢量脉宽调制(SVPWM)方法,即基于随机开关延时-随机零矢量分配的非正弦双随机SVPWM算法。该调制方法根据最近四矢量SVPWM算法,在基波子空间和3次谐波子空间分别合成参考电压矢量,确定占空比和开关动作,并保持采样频率不变,将与采样时刻对应的开关动作在一定范围内随机延时,同时将插入的零矢量作用时间进行随机分配,从而实现开关频率和对称脉冲位置的双随机。仿真和实验结果表明,该调制方法实现了在不影响基波和3次谐波输出的前提下对高次谐波幅值的削弱,达到了谐波分散的目的。     

五相电压源逆变器SVPWM优化算法

为使五相电压源逆变器同时获得最大电压利用率及最小输出电压谐波,在分析两种SVPWM算法调制机理的基础上,设计了一种改进的相邻最近四矢量SVPWM算法。该算法在调制比为0~1.051 4范围内,通过消除谐波空间合成矢量,使得输出电压谐波为零;在调制比为1.051 4~1.23 1范围内,通过优化重新分配电压矢量作用时间来合成参考电压矢量,保证了谐波空间的合成矢量最小,使逆变器工作在最优状态。构建了五相电压源逆变器仿真模型以及FPGA实验平台,仿真和实验结果表明:在整个线性调制范围内,优化算法能够使五相电压源逆变器的输出电压谐波最小。     

开关损耗及共模电压双重优化的三电平PWM算法

针对多电平逆变电路中现有波形调制算法使逆变器产生较高开关损耗和共模电压的问题,通过分析三电平逆变器参考相电压零序分量注入条件,建立相电压调制函数模型,确定降低开关次数与抑制共模电压双重优化目标,分析目标函数中调制度和基波相位角之间的数学关系,提出了一种新型的三电平逆变电路相电压调制波波形变换算法。该算法根据不同的调制度,通过注入适当的零序分量实现调制波波形变换,使开关器件在单个周期内减少1/3开关次数且共模电压幅值最小。仿真和实验结果显示了该算法的可行性和有效性。     

三相逆变器的最小共模电压PWM控制

提出了一种新的三相逆变器抑制共模干扰最优PWM控制策略。该控制方法在常规空间矢量控制策略的基础上,采用构造零矢量的方法来减小逆变器输出的共模电压幅值,并通过免疫算法来计算最优的作用时间,使得三相逆变器输出波形THD最小。本文介绍了算法各个操作步骤和零矢量构造方法的具体实施过程,搭建了基于DSP控制器的动态实验平台进行小容量模拟实验,实验和仿真结果表明该算法所产生的最优PWM控制序列与常规空间矢量控制策略相比不仅能有效地抑制逆变器输出的共模电压幅值,还能明显减小逆变器输出波形的总谐波畸变率。     

注入3次谐波的SPWM调制算法的实现与验证

针对三相逆变器尤其是VSI型逆变器,传统方法采用通过三角载波对正弦参考电压信号进行调制的SPWM控制方法,其基波电压的幅值能够占直流电压约86.6%,该直流电压利用率较低,未能充分利用直流电压。为解决这一问题,对三相电压源型逆变器的相电压通过注入3次谐波的方法,该方法能够提高直流电压利用率。与此同时,由于三相逆变器的对称性,三相平衡,因而3次谐波并不会影响输出电流的谐波特性。最后借助Matlab/Simulink仿真软件对该调制方法的正确和可行性进行仿真和验证。     

Sinusoidal Pulse-width Modulated Three-phase Multi-level Inverter Topology

Abstract—This article presents a sinusoidal pulse-width modulated three-phase multi-level inverter topology. In this configuration, the basic two-level, three-phase inverter is modified to synthesize higher voltage levels by the insertion of two auxiliary switches per phase leg. The multi-level inverter configuration generates output voltage levels similar to the corresponding well-known conventional diode-clamped flying capacitors and cascaded H-bridge inverters but with fewer power circuit components and more simplicity. For output voltage and frequency variations demanded by such applications as variable-speed drives, active power filters, photovoltaic power conversions, etc., the sinusoidal pulse-width modulation technique is employed in the generation of the gating signals for the proposed three-phase multi-level inverter. A balanced three-phase R-L load is applied at the inverter output terminals, and the inverter performance is compared with that of other sinusoidal pulse-width modulated conventional multi-level inverter configurations. The validity of the proposed multi-level inverter topology and the modulation scheme are verified through simulations and experiments.     

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.     

A highly efficient single‐phase sine‐wave inverter with single‐switch high‐frequency modulation

This paper presents a highly efficient single‐phase sine‐wave inverter with single‐switch high‐frequency modulation. In this topology, a control circuit is connected at the lower arm of a full‐bridge inverter to control the output voltage across the full‐bridge inverter. The switch at the lower arm of the full‐bridge inverter controls the output voltage of the full‐bridge inverter by increasing or reducing the voltage level at the lower arm of the inverter. This switch of lower arm is controlled by a high‐frequency sinusoidal pulse width modulation (SPWM) switching signal, while the power switches of the full‐bridge inverter operate with a square‐wave switching signal at the line frequency to unfold DC–AC inversion, thus producing a sinusoidal voltage at the load. Both computer simulation and experiment are carried out to verify the performance of the proposed topology. Experimental results from a 1000‐W laboratory prototype are presented to testify and validate the analysis, design, and performance of the proposed topology. The results show that the proposed topology has nearly sinusoidal output voltage and current waveforms with a total harmonics distortion of less than 5%. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

45°坐标系下级联逆变器简化空间矢量调制及性能优化研究

研究了H桥级联型逆变器在45°坐标系下简化空间矢量调制,其扇区定位与矢量作用时间计算非常简单,并且易于向每相任意个数H桥级联型逆变器扩展。重点研究了45°坐标系中,通过对简化空间矢量调制方法的改进来实现逆变器输出性能的优化。调制方法的改进具体如下:①为了减少逆变器功率器件的开关损耗,研究了开关频率优化算法,在满足逆变器同样输出要求的同时可以有效减少开关次数;②为了减少逆变器产生的共模电压,研究了抑制零序电压输出的调制算法,其可以有效减少逆变器输出电压中的共模电压,使共模电压在极小的电压范围内波动。最后,仿真与实验结果验证了本文所提方法的正确性。     

Waveform compensation of PWM inverter with cyclic fluctuating loads

A repetitive voltage compensation technique that generates a high-quality sinusoidal output voltage from a single-phase pulse width modulation (PWM) inverter used for uninterruptible power supplies is described. A repetitive control technique eliminates the steady-state error in the distorted output voltage caused by cyclic loads. The proposed PWM inverter system uses microprocessor-based closed-loop digital feedback with a sinusoidal reference. The PWM pattern is determined at every sampling instant by the proposed algorithm, implemented by a microprocessor using a set of detected output voltages and the reference signals through one cycle. The system has low distortion and very fast response for AC phase-controlled loads     

基于脉冲阻塞原理的六相连续型交-交变频电源

为充分体现交-交变频电源的优势,在传统的交-交变频技术和脉冲阻塞原理的基础上,论文提出了一种基于脉冲阻塞原理的六相连续型交-交变频电源。该变频电源采用全控型功率器件具有控制灵活、功率器件较少和成本较低等优点。通过脉冲阻塞和变脉宽斩波控制策略的理论分析,推导出了输出电压频率和幅值的相关表达式,实现了输出电压的变频调幅。最后,设计了以dSPACE为控制核心的六相连续型交-交变频电源的半实物仿真平台,分别在两种频率下完成相关实验。实验结果和理论分析一致,验证了基于脉冲阻塞原理的六相连续型交交变频电源的正确性及可行性。     

二极管箝位型多电平逆变器全范围电容电压平衡的PWM调制方法

电容电压偏移是二极管箝位型多电平逆变器的主要缺点。空间矢量调制和正弦载波调制方法,在调制度较高且功率因数较低时,电容电压出现低频波动。该文首先建立含电容电压的二极管箝位型三电平逆变器的脉冲宽度调制(pulse-width modulation,PWM)模型,提出一种新的调制方法,只需满足三相电流之和为零,该方法在任意调制度和功率因数下都能确保电容电位的平衡。并对算法累积误差进行修正。实验结果表明,这种方法较以前的解决方案能更好地平衡电容电压。最后将算法拓展到二极管箝位型任意电平数逆变器的调制中。     

三相电压型逆变器的空间矢量脉宽调制技术

针对传统正弦脉宽调制(SPWM)技术的不足,介绍了空间矢量脉宽调制(SVPWM)技术在三相电压型逆变器中的应用。建立了三相PWM逆变器的数学模型,对SVPWM技术的基本原理进行了分析,在两相静止坐标系下对具体的控制算法进行了推导。在Matlab/Simulink环境下,建立了SVPWM驱动的三相电压型逆变器模型。利用Simulink动态仿真工具实现对SVPWM控制算法的仿真。仿真结果表明,设计方法可行,仿真模型正确。     

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。     

Experimental investigation of input–output characteristics of a travelling-wave ultrasonic motor

Speed, position and load characteristics of the ultrasonic motor is considerably influenced from the input characteristics such as driving frequency, magnitude and phase difference of phase voltages. Input and output characteristics of a traveling-wave ultrasonic motor have been investigated from the experimental point of view in the present study. For this aim, a half-bridge serial-resonance inverter based drive system has been designed and then implemented. The inverter is featured with pulse width modulation and pulse frequency modulation techniques. The frequency, amplitude and phase angle of two-phase sinusoidal output of the driver has been designed to be changed for the control purpose. Then the measuring circuits and tools have been set up to obtain required measurements. Input characteristics such as duty ratio of control signal-dc reference voltage, dc reference voltage-driving frequency and output characteristics such as driving frequency-rotor speed, driving frequency-feedback voltage, phase voltage-rotor speed are obtained from the experiments. Also load characteristics are studied with experiments. Afterwards these characteristics are discussed in details. This study gives a systematical experimental approach in order to demonstrate operating and control principles and characteristics of the travelling-wave ultrasonic motor.