基于MATLAB的单相PWM逆变电路的仿真研究

逆变电路是PWM控制技术最为重要的应用场合。这里在研究单相桥式PWM逆变电路的理论基础上,采用Matlab的可视化仿真工具Simulink建立单相桥式单极性控制方式下PWM逆变电路的仿真模型,通过动态仿真,研究了调制深度、载波频率对输出电压、负载上电流的影响;并分析了输出电压、负载上电流的谐波特性。仿真结果表明建模的正确性,并证明了该模型具有快捷、灵活、方便、直观等一系列特点,从而为电力电子技术教学和研究中提供了一种较好的辅助工具。     

随机载波PWM控制对PMSM谐波抑制的研究

在三相逆变器驱动的永磁同步电机运行过程中,相电流谐波会使永磁同步电机的定子、转子的损耗增大.在严重的电流谐波的影响下,电动机振动和噪声增大,严重影响永磁同步电机的正常运行.针对上述影响,本文引入一种随机载波频率PWM技术,通过随机化载波频率,生成随机频率的PWM波,经逆变器后,对相电流进行适当滤波后控制永磁同步电机,来抑制在控制永磁同步电机运行过程中的相电流和转速谐波,提升永磁同步电机的控制性能.通过与传统的PWM控制方案对比,在仿真和实验结果中发现,随机载波PWM方案对相电流和电机转速的谐波抑制有良好的效果.     

二极管箝位型多电平逆变器载波PWM控制方法的研究

在分析二极管箝位型多电平逆变器不同的载波PWM控制方法的基础,提出了一种新型的载波PWM方法。为了验证所提出的PWM方法，对二极管箝位型五电平逆变器进行了仿真研究。仿真结果表明，该方法在低调制度下具有良好的谐波特性，同时可以提高调制度，增加直流电压利用率。     

光纤干涉传感器相位生成载波解调算法研究

为了解决传统的相位生成载波解调算法中由调制深度漂移引起的解调结果失真现象,采用微分交叉相除的信号解调方法进行了相关的理论分析及仿真验证,得到了一种不受调制深度限制的高性能相位生成载波解调方案.结果表明,在采用不同幅值和频率的待测信号进行仿真时,改进算法的解调性能始终十分优异;且当调制深度的值为典型值2.63rad和2....     

基于TMS320F2812的三电平逆变器载波调制方法研究

主要对二极管箝位型三电平逆变器的拓扑与控制进行了研究,并以此作为进一步研究的基础,对三电平NPC逆变器的载波同相层叠和反相层叠PWM控制方法进行了分析,同时对两种载波层叠方式下输出电压的谐波特性进行了比较,分析了其工作机理和调制算法,在此基础上对基于三角载波层叠式调制算法的实现进行了改进,然后利用Matlab/Simulink仿真软件实现了调制算法的仿真验证,给出了基于先进TMS320F2812DSP设计改进的三角载波层叠式调制方法的控制程序。结果表明,该调制算法非常适用于新型DSP数字化控制软件的实现,控制性能稳定,能获得带死区功能的控制脉冲。     

基于三次谐波注入的级联多电平逆变器

本文详细分析了调制波变换技术和三次谐波注入多电平逆变器的原理,以及三次谐波注入后逆变器的调制信与输入直流电压的关系。并且,分析了在级联多电平逆变器开环PWM控制下,一般SPWM与三次谐波注入的不同。提出三次谐波注入法能够在不影响负载电流电压的情况下实现载波调制的优化控制,提高电压利用率。在Matlab/Simulink环境下通过仿真,证实了理论的正确性。     

电路包络:一种微波电路稳态分析新方法

现代通信信号在射频载波上采用复杂的数字调制(如/4DQPSK,GMSK和QAM)以提高频谱效率。通用的两种仿真技术(时域积分法和谐波平衡法)不能对任意载波频率调制的通信系统进行有效的分析。介绍了可以填补这一空缺的仿真技术,并用该方法对二极管强非线性电路进行了分析。仿真结果表明这种仿真方法是有效的。     

载波相移技术在H桥级联多电平STATCOM中的应用

本文介绍了载波相移技术包括载波相移正弦脉宽调制（CPS-8PWM）和错时采样空间矢量调制（STS—SVM）的基本原理,提出了载波相移正弦脉宽调制和错时采样空间矢量调制在H桥级联多电平STATCOM中的实现方法,并进行了仿真验证。仿真结果表明,基于载波相移正弦脉宽调制和错时采样空间矢量调制的H桥级联多电平STATCOM能...     

并网有源电力滤波器对谐波抑制的分析

并网逆变器采用有源滤波器能对频率变化的谐波以及变化的无功功率进行补偿,考虑调节的方便与载波频率过低时由调制带来的谐波,研究采用异步调制能达到更好的滤波效果与较强的系统稳定性。     

一种室内可见光通信亮度控制方法

为了解决室内无线可见光通信中照明光源亮度不稳定的问题,提出了一种新型的以脉冲宽度调制（PWM）波形作为载波的编码调制方法,设计了基于该方法的发射器和接收器。PWM波形在逻辑1和逻辑0时的载波占空比相同,频率分别为38 kHz和7 kHz。发射端采用高亮度白光LED作为光源,接收端采用PIN光电二极管和低噪声放大器作为前...     

Optimal PWM design for high power three-level inverter throughcomparative studies

Comparative studies between harmonic elimination and optimal PWM strategies are given for high power three-level inverter feeding an induction motor. An effective PWM map construction method based on the valid region on the frequency modulation index plane is suggested. Thereby, an optimal map including asynchronous space vector PWM, harmonic elimination and optimal PWM method is generated covering all of the low, middle and high modulation index regions. The PWM map was designed for 1 MVA rated general purpose GTO inverter and implemented with a digital signal processor. Experimental results are presented for 10 kVA prototype     

基于DSP的单相SVPWM技术与零序信号分析

针对单相全桥PWM逆变器,在研究单相逆变电源电压矢量的基础上,首次将空间矢量脉宽调制(SVPWM)技术应用于单相PWM逆变电源,并给出了单相SVPWM算法的DSP实现方法.通过对单相逆变电压调制信号的频谱分析,给出了单相SVPWM算法的谐波倍频特性;通过对单相SVPWM零电压矢量的分析,提出了一种开关模式优化的单相SVPWM算法;通过对单相SVPWM零序信号的分析,论证了单相SVPWM与载波PWM的统一.实验结果验证了单相SVPWM算法的有效性.     

H桥级联多电平逆变器相移SVPWM技术的研究

载波相移SPWM调制法是级联型逆变器的主流控制方法,其等效载波频率高、谐波特性好、功率单元之间输出功率平衡。而空间矢量法谐波特性好、电压利用率高、控制方法简单便于数字实现。文中针对H桥级联型多电平逆变器的结构特点,综合采用载波移相SPWM法和空间矢量法,并用一种新的空间矢量算法取代传统的方法。该算法中无需三角函数和无理数计算,计算过程非常简单,节约了计算时间,结果更为准确。最后通过系统仿真验证该算法的正确性和有效性。     

Current-source converter on-line pattern generator switchingfrequency minimization

On-line pulsewidth modulation (PWM) pattern generators for current-source rectifiers and inverters offer a number of control advantages over off-line optimized patterns. However, when implemented using the principles which apply to voltage-source inverter PWM pattern generators, the switching frequency is equal to: (1) the carrier frequency in standard carrier-based implementations and (2) a function of the cycle frequency, sequence of space vectors, and selection of the zero space vector in space vector implementations. This paper shows that this frequency can be reduced to one-half of the respective frequencies. Two pattern generators are investigated: (1) an analog on-line carrier-based technique, namely, the modified dead-band technique and (2) a digital on-line space vector-based technique, where advantage is taken of the extra zero state available in current-source converters. It is shown that the switching frequency reduction is achieved with no penalty in the line current harmonic distortion. Moreover, a significant reduction of AC line current distortion is obtained with the modified dead-band technique for modulation indexes greater than 0.4. The principles of operation of the proposed schemes are explained, Experimental results on a 5 kVA current-source rectifier and a 5 kVA current-source inverter confirm the feasibility and features of the proposed pattern generators     

A robust hysteresis current-controlled PWM inverter for linear PMSMdriven magnetic suspended positioning system

Hysteresis current-controlled pulsewidth modulation (PWM) is very robust but it possesses nonconstant switching frequency, and it is difficult to use for high-performance position servo applications. This paper presents a robust hysteresis current-controlled PWM scheme for a magnetic suspended positioning system driven by an inverter-fed linear permanent-magnet synchronous motor having improved performance in these two areas. In the proposed control scheme, the conventional hysteresis PWM mechanism is augmented by a robust harmonic spectrum-shaping controller. The error signal, which represents the switching frequency deviated from the set one, is detected using a notching filter inverse model. Then, the current command is adjusted by a robust compensation signal. The hysteresis band can be equivalently varied to let the dominant harmonic frequency of inverter output be constant, wherein the frequency can easily be changed by tuning the center frequency of the notch filter. The gating signal of switches is not needed to be sensed for making the proposed control. The constant-frequency control performance yielded by the proposed controller is rather insensitive to the system disturbances and the neutral voltage variation due to isolated Y connection. Through applying the proposed PWM inverter, satisfactory position control requirements can be achieved by properly setting the dominant harmonic frequency according to the electromechanical model of the positioning system     

Adaptive frequency domain control of PWM switched power lineconditioner

An adaptive frequency domain control algorithm for a pulse width modulation (PWM) switched active power line conditioner (PLC) is discussed. An active power line conditioner that minimizes harmonic current in the AC line and improves power factor to unity is recommended. A six switch pulse width modulated current source inverter implements the active PLC. Simulation results of the PLC adaptive frequency domain control using the PWM switching algorithm are presented     

Four-wire dynamic voltage restorer based on a three-dimensional voltage space vector PWM algorithm

A modified voltage space vector pulse-width modulated (PWM) algorithm for a four-wire dynamic voltage restorer (DVR) is described. The switching strategy based on a three-dimensional (3-D) /spl alpha//spl beta/O voltage space is applicable to the control of three-phase four-wire inverter systems such as the split-capacitor PWM inverter and the four-leg PWM inverter. In contrast to the conventional voltage space vector PWM method, it controls positive, negative and zero sequence components of the terminal voltages instantaneously. Three 3-D modulation schemes are analyzed with respect to total harmonic distortion (THD), weighted total harmonic distortion (WTHD), neutral line ripple and switching loss over the whole range of the modulation index when the DVR experiences both balanced and unbalanced sags with phase angle jumps. Experimental results from a 9 kW DVR system using a split-capacitor PWM inverter are presented to validate the simulation results.     

交流电动机传动用电压源逆变器损耗的分析

整流器与逆变器是工业变频器中重要的两种变换器,其功率损耗的大小决定于变换器的调制算法、传动系统的负载特性与运行方式等因素,而变换器的功率器件功耗大小又决定了整个变频器的效率、散热处理、安全运行等方面。本文理论推导了普通SPWM、谐波注入PWM、损耗最小PWM、常规SVPWM、以及共模电压抑制时电压源逆变器中功率器件功耗的计算公式,所得结果均得到了仿真分析验证。以22kW工业变频器100A IGBT和SPWM算法为例,进行了初步模拟计算。所推导的功耗计算公式对实际逆变器散热设计具有一定的参考价值。     

Analysis of the synchronized delta modulated PWM inverter: Mathematical model†

In this paper, the performance of a synchronized delta modulated PWM inverter is studied analytically. This modulation strategy allows one to obtain an output waveform continuously variable from a nearly sinusoidal to a square wave without an increase in circuit complexity. The analytical solution allows learning about the harmonic spectra and the amplitude of the first harmonic of the inverter output wave, when the reference frequency varies over a wide range. These results can be profitably used in the inverter design, in order to obtain a proper control circuit according to the power stage requirements.