SVPWM的算法及仿真研究

在分析空间矢量脉宽调制（SVPWM）技术原理的基础上,详细推导了SVPWM算法,并对传统算法进行了过调制处理,使算法得以完善。在MATLAB／SimuIink环境下建立了SVPWM控制的三相电压型逆变器仿真模型。仿真结果表明该算法的正确性和可行性。     

三相电压源整流器最小开关损耗调制算法的研究(上)

三相全桥PWM电压源整流器(VSR)是一种优质的升压型四象限AC·DC变换器,能够输出稳定的直流电压和获得可调的输入电流位移因数。在许多应用领域中.对三相电压源整流器的整体效率要求日益提高。考虑到三相电压源整流器的开关损耗与调制算法密切相关.为此需要改进已有的调制算法.本文在理论上推导了电压源整流器多解性原理基础上.分析了传统SPWM和SVPWM算法的本质联系.提出了一种在三相电压源整流器目标函数中注入零序分量的最小开关损耗SPWM和SVPWM调制算法.并推导了功率器件的功耗计算公式。在利用MATLAB/SIMULINK对采用最小开关损耗SPWM和SVPWM调制算法的整流器进行仿真分析之后,采用DSP F28335实现了最小开关损耗PWM调制算法的电压源整流器实验平台.验证了有关结论。相比传统的SPWM和SVPWM调制算法.最小开关损耗PWM算法能够将整流电路提升效率2~3%     

基波电压线性输出的两相SVPWM算法

本文提出了一种基于基波电压幅值线性输出控制的两相SVPWM过调制算法,该算法不需要存储数据.能够使逆变器平滑的从线性调制工作状态过渡到方波工作状态,非常适合数字化应用。文中分析了应用该算法以后,逆变器输出相电压的谐波畸变（THD）情况,以及主要谐波成分百分含量的变化情况,并和传统两相SVPWM控制算法进行了技术指标对比。分析及仿真证明,该算法具有输出基波电压增益线形和实现简单的优点,非常适合电机实际应用。     

三相电压源整流器最小开关损耗调制算法的研究(下)

三相全桥PWM电压源整流器(VSR)是一种优质的升压型四象限AC-DC变换器,能够输出稳定的直流电压,获得可调的输入电流位移因数。在许多应用领域中,对三相电压源整流器的整体效率要求日益提高。考虑到三相电压源整流器的开关损耗与调制算法密切相关,为此需要改进已有的调制算法。本文在理论上推导了电压源整流器多解性原理基础上,分析了传统SPWM和SVPWM算法的本质联系,提出了一种在三相电压源整流器目标函数中注入零序分量的最小开关损耗SPWM和SVPWM调制算法,并推导了功率器件的功耗计算公式。在利用MATLAB/SIMULINK对采用最小开关损耗SPWM和SVPWM调制算法的整流器进行仿真分析之后,采用DSP TMS320F28335实现了最小开关损耗PWM调制算法的电压源整流器实验平台,验证了有关结论、相比传统的SPWM和SVPWM调制算法,最小开关损耗PWM算法能够将整流电路提升效率2~3%。     

基于DSP的SVPWM与载波PWM的统一性研究

 针对脉宽调制(PWM)逆变器,在研究逆变电源电压矢量的基础上,将空间矢量脉宽调制(SVPWM)技术应用于三相和单相PWM逆变电源,分别给出了三相和单相SVPWM的数字信号处理(DSP)算法,给出了一种开关模式优化的单相SVPWM算法,导出了三相和单相SVPWM基于载波调制的调制波形式以及零序信号形式,指出载波零序信号在本质上对应着逆变器零电压矢量作用时间分配与分布,论证了SVPWM与载波PWM的统一,实验结果验证了SVPWM算法的有效性.     

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.     

三电平变换器SVPWM算法综述

本文介绍了三电平空间矢量脉宽调制（SVPWM）的基本原理,根据空间矢量调制的规律,重点介绍了五种三电平SVPWM算法,并对它们各自的特点进行了分析,包括古典算法;参考电压分解SVPWM算法;基于线电压坐标系的SVPWM算法;基于60°坐标系的SVPWM算法：基于120°坐标系的SVPWM算法。最后针对上述五种算法,对三电平变换器中点电压的平衡控制进行了研究。     

基于SVPWM的三电平NPC-STATCOM功率控制策略及其仿真

基于瞬时功率理论,提出了采用功率和电路参数估算功率补偿装置端口电压的方法,采用60°坐标系下的三电平SVPWM调制算法,避免了传统三电平SVPWM算法复杂的三角函数运算,同时相比传统直接功率控制实现开关器件定频工作,相比于电压电流双环控制省去了锁相环节。最后利用Simulink搭建了NPC-STATCOM的仿真模型,仿真结果表明所提控制方法能够在保持装置直流侧中点电位平衡的基础上迅速对系统进行无功补偿。     

基于TMS320LF2407的空间电压矢量PWM的研究

电压空间矢量脉宽调制是一种先进的调制方法。在分析空间矢量调制(SVPWM)基本原理和输出电压特性的基础上,详细介绍了TMS320LF2407芯片产生SVPWM的硬件结构。结合电机控制专用高速数字信号处理器TMS320LF2407运算速度快、精度高、可以实时完成SVPWM控制算法的特点。给出了一种基于DSP的数字化三相感应电动机控制的软件实现方法,这种方法在三相电压源逆变器中能产生更少的谐波并减少了损耗。     

最小共模电压SVPWM调制算法电压源整流器的研究(上)

本文在基于三相VSR一般数学模型的基础上推导了直流侧共模电压的表达式,分析了理想情况下无死区时和实际情况下有死区时传统SVPWM算法的零矢量和非零矢量对共模电压幅值和谐波分布的影响,并在此基础上提出了一种采用非零矢量等效合成零矢量作用的最小共模电压SVPWM调制算法和共模电压不受死区影响的死区时间设置方法。以上分析得到了MATLAB/SIMULINK仿真分析和变频空调样机的定性验证。结果表明:相比传统采用零矢量的SVPWM算法,最小共模电压SVPWM算法使共模电压的幅值和变化率降低66%,减轻了共模电压干扰。     

Five-stepped PWM inverter used in photovoltaic systems

A PWM (pulse-width-modulated) inverter that has five-stepped output-voltage levels is introduced. In this inverter, the waveform of the output voltage has a smaller harmonic content than that of a conventional PWM inverter. A novel PWM technique is analyzed. The PWM pulses included in the waveform of the output voltage are formed using a criterion based on the calculation that each area of voltage pulses is equal to the integrated value of each time shared area of a reference sinusoidal waveform. This PWM technique for the five-stepped PWM inverter is superior to the conventional PWM technique, and the experimental results coincided with the calculation obtained using the fast Fourier transform. In addition, the relations between the number of PWM pulses and the harmonic contents of the output voltage are described     

Improvement of output voltage control performance for low-speed operation of matrix converter

The matrix converter (MxC) is an ac-to-ac conversion device that can generate variable frequency and variable voltage output. The nine bidirectional switches of an MxC allow pulse-width modulation (PWM) control of input currents and output voltages. PWM switches need "switch commutations" from one switch to another. During these switch commutations, however, unwanted voltage error occurs like a dead time effect in a voltage source inverter (VSI). When PWM pulse-widths are narrower than the time for completing a commutation sequence, voltage error rapidly increases. In the low-speed range, PWM pulses become narrower and voltage distortions become larger due to incomplete commutations. Moreover, these errors are critical in the low-speed operation because the system is sensitive to the smallest voltage error. In this paper, a new PWM strategy is proposed for improving voltage control performance in the low-speed range. Based on the input and output voltage information, PWM pulse-widths are controlled to avoid incomplete commutation. The feasibility of the proposed method is proved through simulation and experimental results.     

High efficiency, unity power factor VVVF drive system of aninduction motor

A high-efficiency, unity-power-factor VVVF (variable voltage, variable frequency) drive scheme for an induction motor is presented. A unity-power-factor PWM (pulsewidth modulated) converter regulates DC voltage. An inverter circuit with the magnetic flux control PWM method generates VVVF PWM waveforms. The modulation factor of the inverter PWM control with controllable DC link DC voltage is studied. As a result, the distortion factor and the switching frequency are reduced by over-modulation with low DC link voltage. A high-efficiency and unity-power-factor VVVF induction motor drive has been achieved using the control strategy     

新型高性能开关电源电压型PWM比较器

设计并实现了一种高性能的电压型PWM比较器,电路采用PMOS差分对管做为输入,多路电流镜提供精密负载电流,具有输入失调电压低、工作频率高、转换速率快和功耗低等优点.该电路可以替代普通电压型PWM比较器,直接运用在开关电源电压型PWM控制芯片中,并且能模块化设计,提高了PWM控制芯片的系统集成.     

Parallel resonant DC link circuit-a novel zero switching losstopology with minimum voltage stresses

A parallel resonant DC link (PRDCL) circuit topology is proposed as an approach to realizing zero switching loss DC-AC high switching frequency power conversion. The proposed circuit is used as an interface between the DC voltage supply and a voltage source pulse width modulated (PWM) inverter to provide a short zero voltage period in the DC link of the inverter to allow zero voltage switchings to take place in the PWM inverter. The peak voltage stress on the PWM inverter switches is limited to the DC supply voltage. Another significant advantage of the circuit is that the inverter can be controlled by the conventional PWM strategy. The proposed circuit is systematically analyzed and its operation principle is explained. Design considerations and design formulas are presented. A complete zero voltage switching DC-AC system consisting of the proposed circuit and a PWM inverter was simulated on a computer     

电流型PWM控制器UC3844及其在微机电源中的应用

针对电压型脉宽调制器(PWM)控制器只有电压控制环、电流变化滞后电压变化、系统响应速度慢、稳定性差等固有缺点,介绍了既有电压控制环、又有电流控制环的新型电流型PWM控制器.分析了电流型PWM控制器与电压型PWM控制器的控制原理,比较了二者之间的优缺点;介绍了电流型PWM控制器UC3844的工作原理,并应用电流型PWM控制器UC3844设计了微机电源,指出了设计中应该注意的问题.结果表明,由电流型PWM控制器构成的微机电源具有良好的电压调整率、负载调整率和系统稳定性等优点.     

直流电机PWM调速系统中控制电压非线性研究

研究了直流电机PWM调速系统中控制电压的非线性,以实现精确的控制。通过实验和理论分析研究了空载情况下电机端电压平均值与电机转速、PWM波占空比与电机端电压平均值之间的非线性关系。实验表明,在不带电机情况下,PWM波占空比与控制输出端电压平均值之间呈线性关系;加入电机后,由于PWM在低电平期间电压的底端值不为0,所以占空比与电机端电压平均值之间呈抛物线关系。     

Single-Phase Multilevel PWM Inverter Topologies Using Coupled Inductors

The number of voltage levels available in pulsewidth modulation (PWM) voltage source inverters can be increased by using a split-wound coupled inductor within each inverter leg and interleaved PWM switching of the upper and lower switches. The magnetizing inductance of the symmetrical split-wound inductor filters the high-frequency PWM voltage differences between the upper and lower switches. The same inductor presents a three-level PWM voltage at the inverter output terminals, with the winding leakage inductance being located in series with the low-frequency output current. Deadtime PWM signal delays can be reduced as dc-rail short circuits are not possible: as a result, the quality and voltage range of the PWM output is improved. Since the inductor windings are technically exposed to high-frequency PWM ac voltages with no dc components, device voltage drops help to reduce the buildup of winding dc currents. Theoretical analysis and a sample design case are presented to illustrate how to design suitable inductors for the various topologies. Simulation and experimental results are used to illustrate the operation of the proposed inverter structures.      

基于空间矢量调制三相电压型PWM整流系统的仿真

正弦脉冲宽度调制(SPWM)技术应用于传统的电压型PWM整流中,SPWM的控制波形可由相间解耦得到。然而,这个过程复杂且直流电压利用率很低。本文提出了一种在同步参考坐标下的三相电压模型的控制策略,空间矢量脉冲宽度调制(SVPWM)。整流器具有高质量的直流侧电压和功率因数。文章提供了MATLAB/SIMULINK的仿真模型。结果证实了模型的正确性及其控制方法。仿真结果表明,与传统的SPWM方法相比,这种方法能明显提高系统的动态性能。     

高频软开关PWM功率变换技术的发展与现状

本文介绍了三类零电压软件开关ＰＷＭ变换器和两类零电流软件开关ＰＷＭ变换器的特点和工作原理。