脉宽调节 pwm spwm 英文翻译(1-3)
SPWM
正弦脉冲宽度调制逆变器
1，定义：控制开关管的通断顺序和时间分配规律，在逆变器输出端获得幅值相等，宽度按正弦规律变化的脉冲序列。
2，PWM的全称是Pulse Width Modulation（脉冲宽度调制），它是通过改变输出方波的占空比来改变等效的输出电压。
3，SPWM，就是在PWM的基础上改变了调制脉冲方式，脉冲宽度时间占空比按正弦规律排列，这样输出波形经过适当的滤波可以做到正弦波输出。
它广泛的用于直流-交流(DC-AC)逆变器等，比如高级一些的UPS就是一个例子。
三相SPWM是使用SPWM模拟市电的三相输出，在变频器领域被广泛的采用。
4，。
一分钟搞明白PWM、SPWM、SVPWM
一分钟搞明白PWM、SPWM、SVPWM1、什么是PWM？PWM是Pulse Width Modulation缩写，中文是脉冲宽度调制。
它是按一定规律改变脉冲序列的脉冲宽度，以调节输出量和波形的一种调制方式。
2、什么是SPWM？SPWM英文是Sinusoidal Pulse Width Modulation ,中文是正弦波脉宽调制，也即Sinusoidal PWM，可以理解为是在PWM的基础上用正弦波来调制合成的具有正弦波规律变化的方波。
3、什么是SVPWM？SVPWM是空间矢量脉宽调制，英文是Space Vector Pulse Width Modulation)。
它与SPWM的原理和来源有很大不同，但是却殊途同归。
可以这样理解，SVPWM是在SPWM的基础上增加三次谐波，或者说，SVPWM却可以看成由载波与有一定三次谐波含量（三次谐波在对称三相系统中抵消）的正弦基波调制而成，以提高电压利用率（SPWM直流电压利用率仅为86.6%）。
4、SVPWM特点是什么？1.在每个小区间虽有多次开关切换，但每次开关切换只涉及一个器件，所以开关损耗小。
2.利用电压空间矢量直接生成三相PWM波，计算简单。
3.逆变器输出线电压基波最大值为直流侧电压，比一般的SPWM逆变器输出电压高15% 5、三种调制方式如何选择？简单来说，三种方式都可以使用。
一般来说，直接用PWM的场合较少，都是非常简单的应用情况下才会使用，因为控制简单，资源占用少。
而用SPWM足够满足大多数场合要求。
非要区分，那就是低频用SPWM多，高频用SVPWM的多，这里说的一般在30HZ以下用SPWM ， 30HZ以上用SVPWM 。
对输出电压有较高要求的用SVPWM。
在实际工程应用中，可能会有几种方式同时使用。
本文只是入门级的介绍，让大家快速地建议一个感性的认识，更复杂部分，在后续文章中列出。
PWM、SPWM、SVPWM三种调制方式的相同点与不同点，你GET了吗?。
pw脉宽调制
任务名称：PW脉宽调制一、引言PW脉宽调制（Pulse Width Modulation，简称PWM）是一种常用的数字控制技术，广泛应用于电子设备、电机驱动、通信系统等领域。
本文将全面探讨PW脉宽调制的原理、应用以及优缺点，帮助读者深入理解该技术。
二、PWM原理2.1 基本概念PW脉宽调制是通过调整信号的脉冲宽度来改变电压或功率等物理量的控制技术。
它采用数字信号来驱动模拟信号，通过周期性的脉冲信号，控制目标物理量的平均值。
2.2 PWM信号生成1.基于定时器的PWM生成: 定时器可以定期产生脉冲信号，PWM信号的占空比通过调整定时器的计数器值来实现。
–步骤1: 初始化定时器的计数器和预设值。
–步骤2: 开始计数，并与预设值进行比较。
–步骤3: 当计数器值小于预设值时，输出高电平；当计数器值大于预设值时，输出低电平。
–步骤4: 重复步骤2和步骤3，实现周期性的PWM信号输出。
2.基于比较器的PWM生成: 通过比较器将模拟信号与参考电压进行比较，产生PWM信号。
–步骤1: 将模拟信号与参考电压输入到比较器。
–步骤2: 比较器将模拟信号与参考电压进行比较，并输出PWM信号。
三、PWM的应用3.1 电子设备1.直流电源: PWM可以用于直流电源的电压调节，控制输出电压的稳定性和效率。
2.LED灯光控制: 通过PWM调节LED的亮度，实现灯光的亮度调节和颜色混合。
3.伺服电机控制: PWM信号可以用于控制电机的转速和运动方向。
3.2 电机驱动1.直流电机控制: PWM可以用于直流电机的速度调节和逆变器的控制。
2.步进电机控制: 通过PWM信号控制步进电机的步进角度，实现精确的位置控制。
3.3 通信系统1.无线通信: PWM技术可以用于无线通信系统的调制与解调，提高通信信号的质量。
2.数字音频: PWM可以用于数字音频信号的解码和重构，实现高保真音频输出。
四、PWM技术的优缺点4.1 优点1.高效能: PWM技术通过调整信号的占空比，减少了能量的损耗，提高了系统的能效。
正弦波脉宽调制SPWM
三相桥式PWM逆变器的双极性SPWM波形
上图为三相PWM波形，其中 urU 、urV 、urW为U，V，W三相的正弦调制波， uc为双极性三角载波； uUN’ 、uVN’ 、uWN’ 为U，V，W三相输出与电源
中性点N’之间的相电压矩形波形；
uUV为输出线电压矩形波形，其脉冲幅值为+Ud和
根据载波和信号波是否同步及载波比的 变化情况，PWM调制方式分为异步调制和 同步调制。
（1）异步调制 异步调制——载波信号和调制信号不 同步的调制方式。
通常保持 fc 固定不变，当 fr 变化时，载 波比 N 是变化的；
在信号波的半周期内，PWM波的脉冲个 数不固定，相位也不固定，正负半周期 的脉冲不对称，半周期内前后1/4周期的 脉冲也不对称；
为使一相的PWM波正负半周镜对称，N 应取奇数；
不易滤除；
fr 很低时，f使开关器件难以承
受。
•同步调制三 相PWM波形
u
u rU
uc
u rV
u rW
O
t
u UN'
Ud 2 Ud 2
0
t
u VN' 0 u WN' t
0
t
（3）分段同步调制
1 M sin r tD 2 /2 Tc / 2
因此可得
Tc (1 M sin r t D ) 2
三角波一周期内，脉冲两边间隙宽度
Tc 1 ' Tc (1 M sin r tD ) 2 4
根据上述采样原理和计算公式，可以用 计算机实时控制产生SPWM波形，具体实 现方法有：
VT V 1 1
电力拖动自动控制系统（名词解释）
电力拖动自动控制系统（名词解释）一、名词解释：1.G-M系统（旋转变流机组）：由交流电动机拖动直流发电机G实现变流，由G给需要调速的直流电动机M供电，调节G的励磁If即改变其输出电压U，从而调节电动机的转速n，这样的调速系统简称G-M系统，国际上统称Ward-Leonard系统。
2.V-M 系统（晶闸管-电动机调速系统）：通过调解器触发装置GT的控制电压Uc来移动触发脉冲的相位，即可改变平均整流电压Ud，从而实现评平滑调速，这样的系统叫V-M系统。
3. （SPWM）：按照波形面积相等的原则，每一个矩形波的面积与相应位置的正弦波面积相等，因而这个序列的矩形波雨期望波的争先等效，这种调制方法称作正弦波脉宽调制（SPWM）。
4.（旋转编码器的测速方法）M法测速——在一定时间Tc内测取旋转编码器输出的脉冲个数M1,用以计算这段时间内的平均转速，称作M法测速。
T法测速——在编码器两个相邻输出脉冲间隔时间内，，用一个计数器对已知频率为f0的高频时钟脉冲进行计数，并由此来计算转速，称作T法测速。
M/T法测速——既检测Tc时间内旋转编码器输出的脉冲个数M1，又检测用一时间间隔的高频时钟脉冲个数M2，用来计算转速，称作M/T法测速。
5.无刷电动机：磁极仍为永磁材料，但输出方波电流，气隙磁场呈梯形波分布，这样就更接近于直流电动机，但没有电刷，故称无刷电动机（梯形波永磁同步电动机）。
6.DTC（直接转矩控制系统）：它是利用转矩反馈直接控制电机的电磁转矩，是既矢量控制系统之后发展起来的另一种高动态性能的交流电动机变压变频调速系统。
7.恒Eg/f1=C控制：对于三相异步电动机，要保持气隙磁通不变，当频率从额定值向下调节时，必须同时降低气隙磁通在在定子每相中感应电动势的有效值Eg，使Eg/f1=恒定值，像这样的控制方法叫恒Eg/f1=C控制。
（譬如，对于异步电动机，如果在电压-频率协调控制中，恰当地提高电压Us的数值，使它在克服钉子阻抗压降以后，能维持Eg/f1为恒值，这种控制方法叫Eg/f1=C控制。
pwm的工作原理
pwm的工作原理PWM的全称是Pulse Width Modulation，中文意思是脉宽调制。
它是一种通过改变脉冲信号的宽度来传输信息的调制方式。
在现代电子技术中，PWM被广泛应用于电力电子、通信、自动控制等领域。
本文将介绍PWM的工作原理及其在实际应用中的特点和优势。
PWM的工作原理。
PWM的工作原理可以简单描述为通过改变脉冲信号的占空比来控制电路的输出。
在一个完整的PWM周期内，包括一个固定频率的周期性脉冲信号和一个可变的占空比。
占空比是指脉冲信号中高电平时间占整个周期的比例，通常用百分比表示。
在PWM信号中，当占空比为50%时，表示高电平和低电平的时间相等，这时电路的输出为中间值。
当占空比小于50%时，高电平时间减少，电路的输出信号会相应减小；反之，当占空比大于50%时，高电平时间增加，电路的输出信号会相应增大。
通过调整占空比，可以实现对电路输出的精确控制。
PWM的实现方式。
PWM信号的生成可以通过硬件电路或者软件算法来实现。
在硬件电路中，常用的方法是利用定时器来生成固定频率的脉冲信号，然后通过比较器来调整占空比。
而在软件算法中，可以通过程序控制IO口的高低电平来实现PWM信号的输出。
在实际应用中，PWM信号通常用来控制电机的转速、调节LED 的亮度、调节电源的输出等。
例如，通过改变电机驱动器输入的PWM信号占空比，可以实现电机的精确转速调节；通过改变LED驱动电路输入的PWM信号占空比，可以实现LED灯的亮度调节。
PWM的特点和优势。
与传统的模拟调制方式相比，PWM具有以下几点特点和优势：1. 精确控制，通过改变占空比，可以实现对电路输出信号的精确控制，具有较高的分辨率和稳定性。
2. 能效高，PWM信号的平均功率较高，能够提高电路的能效，减小能量损耗。
3. 抗干扰能力强，PWM信号的数字特性使其具有较强的抗干扰能力，能够适应复杂的工作环境。
4. 适应性强，PWM信号可以适用于不同类型的电路和设备，具有较强的通用性和灵活性。
pwm波形
③不用载波，输出电压波形中不含特定频率的谐波分量；
④与计算法和调制法相比，相同开关频率时输出电流中高次谐波含量较多；
⑤采用闭环控制.
特点
若令频率不变，直接改变脉冲的宽度，亦即控制开关元件的导通时间；比如现在是高电平导通，那么方波的A越大，B越小，导通时间就长；否则就越短。
方波的占空比被调制用来对一个具体模拟信号的电平进行编码。
PWM信号仍然是数字的，
因为在给定的任何时刻，满幅值的直流供电要么完全有（ON），要么完全无（OFF）。
电压或电流源是以一种通（ON）或断（OFF）的重复脉冲序列被加到模拟负载上去的。
通的时候即是直流供电被加到负载上的时候，断的时候即是供电被断开的时候。
应用举例
电流跟踪型PWM变流电路就是对变流电路采用电流跟踪控制。
也就是，不用信号波对载波进行调制，而是把希望输出的电流作为指令信号，把实际电流作为反馈信号，
通过二者的瞬时值比较来决定逆变电路各功率器件的通断，使实际的输出跟踪电流的变化。
采用滞环比较方式的电流跟踪型变流器的特点：
①硬件电路简单；
只要带宽足够，任何模拟值都可以使用PWM进行编码。
PWM波形
PWM控制技术就是对半导体开关器件的导通和关断进行控制，
使输出端得到一系列幅值相等而宽度不相等的脉冲，用这些脉冲来代替正弦波或其他所需要的波形。
按一定的规则对各脉冲的宽度进行调制，既可改变逆变电路输出电压的大小，也可改变输出频率。
PWM波形 锁定
PWM就是脉冲宽度调制，也就是占空比可变的脉冲波形.
中文名 脉冲宽度调制波形 外文名 PWM wave
基于单片机的直流电机PWM调速控制的英文翻译
三相PWM升降压整流器的功率再生性能Jun Kikuchi , Student Member, IEEE, and Thomas A. Lipo, Fellow, IEEEPaper IPCSD 02–038, presented at the 2001 Industry Applications Society Annual Meeting, Chicago, IL, September 30–October 5, and approved for pub-lication in the IEEE T RANSACTIONS ON INDUSTRY APPLICATIONS by the Indus-trial Power Converter Committee of the IEEE Industry Applications Society.Manuscript submitted for review October 15, 2001 and released for publication June 11, 2002.The authors are with the Department of Electrical and Computer Engi-neering, University of Wisconsin,Madison,WI53706-1691USA(e-mail:****************.edu;**************.edu). Publisher Item Identifier 10.1109/TIA.2002.802910.摘要：抽象概念---三相PWM升降压整流器的功率再生性能已被调查。
这个转换器在考虑下有以下功能：(1)、两个电压的升压和降压；（2）、双向动力处理；（3）、大多数单位功率因素由正弦交流电流操作；预期的优点有：（1）、低电压的应用程序的适应性，例如：直接改造来代替二极管或可控硅整流器；（2）、开关损耗降低逆变器负荷；（3）、低次谐波控制逆变器负载输出电压；（4）、落料时间效应缓解在逆变器中的负载；（5）、一个中等水平的电压凹陷或膨胀补偿；在这篇论文中，首先是一个循序渐进的功率级推导过程的描述，其次是，把Cuk-Cuk 的实现作为一个例子，它的工作原理和调制方案可被描述，同时还描述了一个稳态和动态模型控制器设计，电路仿真和典型结果给出了硬件实验。
LED照知识：PWM调光（英文说明）
LED照知识：PWM调光（英⽂说明）A matter of light：PWM dimmingWhether you drive LEDs with a buck, boost, buck-boost or linear regulator, the common thread is drive circuitry to control the light output. A few applications are as simple as ON and OFF, but the greater number of applications call for dimming the output between zero and 100 percent, often with fine resolution. The designer has two main choices: adjust the LED current linearly (analog dimming), or use switching circuitry that works at a frequency high enough for the eye to average the light output (digital dimming). Using pulse-width modulation (PWM) to set the period and duty cycle (Fig. 1) is perhaps the easiest way to accomplish digital dimming, and a buck regulator topology will often provide the best performance.THE RECOMMENDED PWM DIMMERwith waveforms.PWM dimming preferred Analog dimming is often simpler to implement. We vary the output of the LED driver in proportion to a control voltage. Analog dimming introduces no new frequencies as potential sources of EMC/EMI. However, PWM dimming is used in most designs, owing to a fundamental property of LEDs: the character of the light emitted shifts in proportion to the average drive current. For monochromatic LEDs, the dominant wavELength changes. For white LEDs, the correlated color temperature (CCT) changes. It's difficult for the human eye to detect a change of a few nanometers in a red, green, or blue LED, especially when the light intensity is also changing.A change in color temperature of white light, however, is easily detected. Most white LEDs consist of a die that emits photons in the blue spectrum, which strike a phosphor coating that in turn emits photons over a broad range of visible light. At low currents the phosphor dominates and the light tends to be more yellow. At high currents the blue emission of the LED dominates, giving the light a blue cast, leading to a higher CCT. In applications with more than one white LED, a difference in CCT between two adjacent LEDs can be both obvious and unpleasant. That concept extends to light sources that blend light from multiple monochromatic LEDs. When we have more than one light source, any difference between them jars the senses.LED manufacturers specify a certain drive current in the electrical characteristics tables of their products, and they guarantee the dominant wavelength or CCT only at those specified currents. Dimming with PWM ensures that the LEDs emit the color that the lighting designer needs, regardless of the intensity. Such precise control is particularly important in RGB applications where we blend light of different colors to produce white.From the driver IC perspective, analog dimming presents a serious challenge to the output current accuracy. Almost every LED driver uses a resistor of some type inseries with the output to sense current. The current-sense voltage, VSNS, is selected as a compromise to maintain low power dissipation while keeping a high signal-to-noise ratio (SNR). Tolerances, offsets, and delays in the driver introduce an error that remains relatively fixed. To reduce output current in a closed-loop system, VSNS, must be reduced. That in turn reduces the output current accuracy and ultimately the output current cannot be specified, controlled, or guaranteed. In general, dimming with PWM allows more accurate, linear control over the light output down to much lower levels than analog dimming.DRIVE CHIP GENERAL DESCRIPTIONThe PT4115 is a continuous conduction mode inductive step-down converter, designed for driving single or multiple series connected LED efficiently from a voltage source higher than the total LED chain voltage. The device operates from an input supply between 8V and 30V and provides an externally adjustable output current of up to 1.2A. Depending upon the supply voltage and external components, thePT4115can provide more than 30 watts of output power. The PT4115 includes the power switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current, and a dedicated DIM input accepts either a DC voltage or a wide range of pulsed dimming. Applying a voltage of 0.3V or lower to the DIM pin turns the output off and switches the device into a low current standby state. The PT4115 is available in SOT89-5 and ESOP8 packages.FEATURESSimple low parts countWide input voltage range: 8V to 30VUp to 1.2A output currentSingle pin on/off and brightness control using DC voltage or PWMUp to 1MHz switching frequencyTypical 5% output current accuracyInherent open-circuit LED protectionHigh efficiency (up to 97%)High-Side Current SenseHysteretic Control: No CompensatioAdjustable Constant LED CurrentESOP8 package for large output power application APPLICATIONSLow voltage halogen replacement LEDs Automotive lightingLow voltage industrial lightingLED back-up lightingIlluminated signsSELV lightingLCD TV backlightingOPERATION DESCRIPTIONThe device, in conjunction with the coil (L1) and current sense resistor (RS), forms a self oscillatingcontinuous-mode buck converter. When input voltage VIN is first applied, the initial current in L1 and RS is zero and there is no output from the current sense circuit. Under this condition, the output of CS comparator is high. This turns on an internal switch and switches the SW pin low, causing current to flow from VIN to ground, via RS, L1 and the LED(s). The current rises at a rate determined by VIN and L1 to produce a voltage ramp (VCSN) across RS. When (VIN-VCSN) > 115mV, the output of CS comparator switches low and the switch turns off. The current flowing on the RS decreases at another rate. When (VIN-VCSN) < 85mV, the switch turns on again and the mean current on the LED is determined byThe high-side current-sensing scheme and on-board current-setting circuitry minimize the number of external components while delivering LED current with ±5% accuracy, using a 1% sense resistor. The PT4115 allow dimming with a PWM signal at the DIM input. A logic level below 0.3V at DIM forces PT4115 to turn off the LED and the logic level at DIM must be at least 2.5V to turn on the full LED current. The frequency of PWM dimming ranges from 100Hz to more than 20 kHz. The DIM pin can be driven by an external DC voltage (VDIM) to adjust the output current to a value below the nominal average value defined by RS. The DC voltage is valid from 0.5V to 2.5V. When the dc voltage is higher than 2.5V, the output current keeps constant. The LED current also can be adjusted by a resistorconnected to the DIM pin. An internal pull-up resistor (typical 200KΩ) is connected to a 5V internal regulator. The voltage of DIM pin is divided by the internal and external resistor. The DIM pin is pulled up to the internal regulator (5V) by a 200KΩresistor. It can be floated at normal working. When a voltage applied to DIM falls below the threshold (0.3V nom.), the output switch is turned off. The internal regulator and voltage reference remain powered during shutdown to provide the reference for the shutdown circuit. Quiescent supply current during shutdown is nominally 95uA and switch leakage is below 5uA. Additionally, to ensure the reliability, the PT4115 is built with a thermal shutdown (TSD) protection and a thermal pad. The TSD protests the IC from over temperature (160℃). Also the thermal pad enhances power dissipation. As a result, the PT4115 can handle a large amount of current safely.。
脉冲宽度调制(PWM)和正弦波脉宽调制(SPWM)变频技术简介
变频技术之PWM调制技术与SPWM调制技术详解变频技术通过改变电力信号的频率来调节电动机、压缩机和其他电气设备的运行速度。
在实际应用中，变频器是变频技术的核心装置，而脉冲宽度调制（PWM）技术和正弦波脉宽调制（SPWM）技术是实现变频器控制的重要手段。
什么是PWM调制技术PWM调制技术通过控制脉冲信号的宽度，实现对输出电压的调节。
在变频技术中，PWM被广泛应用于变频器中，以控制电动机的速度和转矩输出。
通过改变脉冲信号的占空比（脉冲宽度与周期之比），可以实现对电动机的精确控制。
当需要增大输出电压时，增加脉冲信号的宽度；当需要减小输出电压时，减小脉冲信号的宽度。
这种方式使得电动机可以在不同负载条件下保持稳定的转速和扭矩输出。
同时，PWM调制技术还具有响应快、控制精度高、效率高等优点，被广泛应用于各种电力控制系统中。
PWM调制波形如图1所示：图1PWM调制波形PWM技术具有以下优点：高效性：由于PWM技术可以通过调整脉冲宽度来控制电机的输出电压和频率，因此可以实现电机在不同负载条件下的高效运行。
通过减小电机额定电压，PWM技术可以降低电机的功耗，提高整体效率。
精确控制：PWM技术具有响应速度快、控制精度高的特点。
通过微调脉冲宽度和周期，可以实现对电机转速和扭矩的精确调节，满足不同应用的需求。
减少机械冲击：PWM技术可以实现电机的软启动和软停止，减少了机械系统的冲击和磨损，延长了设备的使用寿命。
尽管PWM技术具有许多优点，但也存在一些局限性：谐波问题：PWM技术在产生脉冲信号时会引入谐波成分，可能对电力网络和其他设备造成干扰。
为了减少谐波，需要采取滤波和抑制措施，增加了系统的复杂性和成本。
开关损耗：PWM技术使用高频开关装置，开关的频繁操作会产生开关损耗。
这些损耗会转化为热能，需要适当的散热系统来冷却电路。
EMI干扰：由于高频开关操作，PWM技术可能会产生电磁干扰（EMI），对周围的电子设备和无线通信系统造成干扰。
PWM（脉冲宽度调制PulseWidthModulation）原理
PWM（脉冲宽度调制PulseWidthModulation）原理1、 PWM原理2、调制器设计思想3、具体实现设计⼀、 PWM（脉冲宽度调制Pulse Width Modulation）原理：脉冲宽度调制波通常由⼀列占空⽐不同的矩形脉冲构成，其占空⽐与信号的瞬时采样值成⽐例。
图1所⽰为脉冲宽度调制系统的原理框图和波形图。
该系统有⼀个⽐较器和⼀个周期为Ts的锯齿波发⽣器组成。
语⾳信号如果⼤于锯齿波信号，⽐较器输出正常数A，否则输出0。
因此，从图1中可以看出，⽐较器输出⼀列下降沿调制的脉冲宽度调制波。
通过图1b的分析可以看出，⽣成的矩形脉冲的宽度取决于脉冲下降沿时刻t k时的语⾳信号幅度值。
因⽽，采样值之间的时间间隔是⾮均匀的。
在系统的输⼊端插⼊⼀个采样保持电路可以得到均匀的采样信号，但是对于实际中tk-kTs<（1）其中，x{t}是离散化的语⾳信号；Ts是采样周期；是未调制宽度；m是调制指数。
然⽽，如果对矩形脉冲作如下近似：脉冲幅度为A，中⼼在t = k Ts处，在相邻脉冲间变化缓慢，则脉冲宽度调制波x p(t)可以表⽰为：（2）其中，。
⽆需作频谱分析，由式（2）可以看出脉冲宽度信号由语⾳信号x(t)加上⼀个直流成分以及相位调制波构成。
当时，相位调制部分引起的信号交迭可以忽略，因此，脉冲宽度调制波可以直接通过低通滤波器进⾏解调。
⼆、数字脉冲宽度调制器的实现：实现数字脉冲宽度调制器的基本思想参看图2。
图中，在时钟脉冲的作⽤下，循环计数器的5位输出逐次增⼤。
5位数字调制信号⽤⼀个寄存器来控制，不断于循环计数器的输出进⾏⽐较，当调制信号⼤于循环计数器的输出时，⽐较器输出⾼电平，否则输出低电平。
循环计数器循环⼀个周期后，向寄存器发出⼀个使能信号EN，寄存器送⼊下⼀组数据。
在每⼀个计数器计数周期，由于输⼊的调制信号的⼤⼩不同，⽐较器输出端输出的⾼电平个数不⼀样，因⽽产⽣出占空⽐不同的脉冲宽度调制波。
单极性spwm与双极性spwm区别
PWM 即Pulse Width Modulation翻译成中文就是脉宽调制，就是不同占空比的矩形波。
单极性PWM：电压全部是正的。
控制信号最初都是这个，下面两个都是从这个转换过去的。
双极性PWM：电压有正有负。
SPWM 即Sinusoidal PWM：就是不同占空比的’正弦波‘。
这个在私服电机驱动方面很常用。
pwn应该是PWM，即脉冲宽度调制，就是用三角波信号与正弦波信号相比较，以决定逆变器开关器件的导通或关断。
如果三角波信号在正弦波信号的半个周期都是正值，另外半个周期都是负值，则称为单极性调制；否则，称为双极性调制。
要注意三角波信号的频率必须是正弦波信号频率的整数倍。
一、指代不同1、单极性PWM调制：单极性PWM就是PWM波形在半个周期中只在单极性范围内变化。
2、双极性PWM调制：双极性PWM就是PWM波形在半个周期中有正、有负。
二、原理不同1、单极性PWM调制：由同极性的三角波载波信号ut。
与调制信号ur，产生单极性的PWM脉冲；然后将单极性的PWM脉冲信号的倒相信号UI相乘，从而得到正负半波对称的PWM脉冲信号Ud。
2、双极性PWM调制：采用的是正负交变的双极性三角载波ut与调制波ur，可通过ut与ur，的比较直接得到双极性的PWM脉冲，而不需要倒相电路。
三、特点不同1、单极性PWM调制：启动快，能加速，刹车，能耗制动，能量反馈，调速性能不如双极模式好，但是相差不多，电机特性也比较好。
如果接成H 桥模式，也能实现反转。
在负载超速时也能提供反向力矩。
2、双极性PWM调制：能正反转运行，启动快，调速精度高，动态性能好，调速静差小，调速范围大，能加速，减速，刹车，倒转，能在负载超过设定速度时，提供反向力矩,能克服电机轴承的静态摩擦力，产生非常低的转速。
spwm
1.4 梯形波与三角波比较法[2]
前面所介绍的各种方法主要是以输出波形尽量接近正弦波为目的,从而忽视了直流电压的利用率,如SPWM法,其直流电压利用率仅为86.6%.因此,为了提高直流电压利用率,提出了一种新的方法--梯形波与三角波比较法.该方法是采用梯形波作为调制信号,三角波为载波,且使两波幅值相等,以两波的交点时刻控制开关器件的通断实现PWM控制.
1.3.1 等面积法
该方案实际上就是SPWM法原理的直接阐释,用同样数量的等幅而不等宽的矩形脉冲序列代替正弦波,然后计算各脉冲的宽度和间隔,并把这些数据存于微机中,通过查表的方式生成PWM信号控制开关器件的通断,以达到预期的目的.由于此方法是以SPWM控制的基本原理为出发点,可以准确地计算出各开关器件的通断时刻,其所得的的波形很接近正弦波,但其存在计算繁琐,数据占用内存大,不能实时控制的缺点.
1.3.2 硬件调制法
硬件调制法是为解决等面积法计算繁琐的缺点而提出的,其原理就是把所希望的波形作为调制信号,把接受调制的信号作为载波,通过对载波的调制得到所期望的PWM波形.通常采用等腰三角波作为载波,当调制信号波为正弦波时,所得到的就是SPWM波形.其实现方法简单,可以用模拟电路构成三角波载波和正弦调制波发生电路,用比较器来确定它们的交点,在交点时刻对开关器件的通断进行控制,就可以生成SPWM波.但是,这种模拟电路结构复杂,难以实现精确的控制.
1.3.3 软件生成法
由于微机技术的发展使得用软件生成SPWM波形变得比较容易,因此,软件生成法也就应运而生.软件生成法其实就是用软件来实现调制的方法,其有两种基本算法,即自然采样法和规则采样法波为调制波,等腰三角波为载波进行比较,在两个波形的自然交点时刻控制开关器件的通断,这就是自然采样法.其优点是所得SPWM波形最接近正弦波,但由于三角波与正弦波交点有任意性,脉冲中心在一个周期内不等距,从而脉宽表达式是一个超越方程,计算繁琐,难以实时控制.
正弦脉宽调制(中英文)
Sinusoidal Pulse Width Modulation(SPWM)正弦脉宽调制(SPWM)The switches in the voltage source inverter(See Fig.1)can be turned on and off as required.In the simplest approach,the top switch is turned on If turned on and off only once in each cycle,a square wave waveform results.However,if turned on several times in a cycle an improved harmonic profile may be achieved.Fig 1:Simple Voltage SourcedIn the most straightforward implementation,generation of the desired output voltage is achieved by comparing the desired reference waveform(modulating signal)with a high-frequency triangular…carrier‟wave as depicted schematically in Fig.2.Depending on whether the signal voltage islarger or smaller than the carrier waveform,either the positive or negative dc bus voltage is applied at the output.Note that over the period of one triangle wave,the average voltage appliedto the load is proportional to the amplitude of the signal(assumed constant)during this period.The resulting chopped square waveform contains a replica of the desired waveform in its low frequency components,with the higher frequency components being at frequencies of a close to thecarrier frequency.Notice that the root mean square value of the ac voltage waveform is still equalto the dc bus voltage,and hence the total harmonic distortion is not affected by the PWM process.The harmonic components are merely shifted into the higher frequency range and are automatically filtered due to inductances in the ac system.When the modulating signal is a sinusoid of amplitude Am,and the amplitude of the triangularcarrier is Ac,the ratio m=Am/Ac is known as the modulation index.Note that controlling themodulation index therefor controls the amplitude of the applied output voltage.With a sufficientlyhigh carrier frequency(see Fig.3 drawn for fc/fm=21 and t=L/R=T/3;T=period of fundamental),the high frequency components do not propagate significantly in the ac network(or load)due the presence of the inductive elements.However,a higher carrier frequency does result in alarger number of switchings per cycle and hence in an increased power loss.Typically switchingfrequencies in the 2-15 kHz range are considered adequate for power systems applications.Alsoin three-phase systems it is advisable touse s so that all three waveforms aresymmetric.Fig 2:Principal of Pulse Width ModulationFig.3:SPWM with fc/fm=48,L/R=T/3Note that the process works well form ≤1.For m >1,there are periods of the triangle wave in which there is no intersection of the carrier and the signal as in Fig.4.However,a certain amountof this“overmodulation”is often allowed in the interest of obtaining a larger ac voltage magnitude even though the spectral content of the voltage is rendered somewhat poorer.Note that with an odd ratio for fc/fm,the waveform is anti-symmetric over a 360 degree cycle. With an even number,there are harmonics of even order,but in particular also a small dc component.Hence an even number is not recommended for single phase inverters,particularly for smalratios of fc/fm.SPWM Spectra:Although the SPWM waveform has harmonics of several orders in the phase voltage waveform, the dominant ones other than the fundamental are of order n and n±2 where n=fc/fm.This is evident for the spectrum for n=15 and m=0.8 shown in Fig.5.Note that if the other two phases are identically generated but 120o apart in phase,the line-line voltage will not have any triplenharmonics.Hence it is advisable to choose,as then the dominant harmonic will be eliminated.It is evident from Fig 5b,that the dominant 15th harmonic in Fig.5a is effectively eliminated in the line voltage.Choosing a multiple of 3 is also convenient as then the same triangular waveform can be used as the carrier in all three phases,leading to some simplification inhardware.It is readily seen that as the where E is the dc bus voltage,that the rms valueof the output voltage signal is unaffected by the PWM process.This is strictly true for the phase voltage as triplen harmonic orders are cancelled in the line voltage.However,the problematic harmonics are shifted to higher orders,thereby making filtering much easier.Often,the filtering is carried out via the natural high-impedance characteristic of the load.Fig.5:SPWM Harmonic Spectra:n=15,m=0.Selective Harmonic Elimination(also called Optimal PWM)Notice that in the SPWM strategy developed above,a large number of switchingsare required, with the consequent associated switching losses.With the method of Selective Harmonic Elimination,only selected harmonics are eliminated with the smallest number of switchings.This methodhowever can be difficult to implement on-line due to computation and memory requirements.For a two level PWM waveform with odd and halfwave symmetries and n chops per quarter cycle as shown in Fig 4,the peak magnitude of the harmonic components including the fundamental, are given byEqn.1:Here is the magnitude of the harmonic and is the primary switching angle.Even harmonics do not show up because of the half-wave symmetry.The n chops in the waveform afford n degrees of freedom.Several control options are thus possible.For example n selected harmonics can be eliminated.Another option which is used here is toeliminate n-1 selected harmonics and use the remaining degree of freedom to control the fundamental frequency ac voltage.To find theα‟s required to achieve this objective,it is sufficient toset the corresponding h‟s in the above equations to the desired values(0 for the n-1 harmonics tobe eliminated and the desired per-unit ac magnitude for the fundamental)and solve for theα‟s.Fig 4:A two-level PWM waveform with odd and halfwavesymmEquation 1 can be readily proved by finding the fourier coefficients of the waveform showninFig.4.In general,for a periodic waveform with period,the Fourier Cosine and Sine Coefficients are given by:Because of the half-cycle symmetry of the waveform of Fig.4,only odd order harmonics exist. Also,it is easy to see that the Fourier Cosine coefficients disappear with the choice of coordinate axes used.Utilizing the quarter cycle symmetry,the Fourier Sine coefficients become:Substituting the two-valued PWM waveform for,one obtains(see Fig.4):The following example illustrates the use of three chops per quarter cycle which allow for three degrees of freedom.We may use these to eliminate two harmonics and control the magnitude of the fundamental to any desired value:Example:Selective Harmonic Elimination is applied with a view to controlling the fundamental component of voltage to 50V(rms)and eliminating the 3rd and 5th harmonics.The source voltage is 100 V. Calculate the required chopping angles.As three objectives are to be achieved,we need 3 chops.The fundamental,3rd and 5th harmonic magnitudes are given by:We require:正弦脉宽调制电压源逆变器的开关（见图1）可以按要求打开和关闭。
脉宽调制器与通用定时器中英文对照外文翻译文献
中英文资料外文翻译文献(文档含英文原文和中文翻译)ARM Cortex-M3脉宽调制器(PWM)与通用定时器1.PWM脉宽调制（PWM）是一项功能强大的技术，它是一种对模拟信号电平进行数字化编码的方法。
在脉宽调制中使用高分辨率计数器来产生方波，并且可以通过调整方波的占空比来对模拟信号电平进行编码。
PWM通常使用在开关电源（switching power）和电机控制中。
StellarisPWM模块由3个PWM发生器模块1个控制模块组成。
每个PWM 发生器模块包含1个定时器（16位递减或先递增后递减计数器），2个PWM比较器，PWM信号发生器，死区发生器和中断/ADC-触发选择器。
而控制模块决定了PWM 信号的极性，以及将哪个信号传递到管脚。
每个PWM发生器模块产生两个PWM信号，这两个PWM信号可以是独立的信号（基于同一定时器因而频率相同的独立信号除外），也可以是一对插入了死区延迟的互补（complementary）信号。
这些PWM发生模块的输出信号在传递到器件管脚之前由输出控制模块管理。
StellarisPWM模块具有极大的灵活性。
它可以产生简单的PWM信号，如简易充电泵需要的信号；也可以产生带死区延迟的成对PWM信号，如供半-H桥（half-H bridge）驱动电路使用的信号。
3个发生器模块也可产生3相反相器桥所需的完整6通道门控。
PWM定时器每个PWM发生器的定时器都有两种工作模式：递减计数模式或先递增后递减计数模式。
在递减计数模式中，定时器从装载值开始计数，计数到零时又返回到装载值并继续递减计数。
在先递增后递减计数模式中，定时器从0开始往上计数，一直计数到装载值，然后从装载值递减到零，接着再递增到装载值，依此类推。
通常，递减计数模式是用来产生左对齐或右对齐的PWM信号，而先递增后递减计数模式是用来产生中心对齐的PWM信号。
PWM定时器输出3个信号，这些信号在生成PWM信号的过程中使用：方向信号（在递减计数模式中，该信号始终为低电平，在先递增后递减计数模式中，则是在低高电平之间切换）；当计数器计数值为0时，一个宽度等于时钟周期的高电平脉冲；当计数器计数值等于装载值时，一个宽度等于时钟周期的高电平脉冲。
这个PWM和SPWM到是什么鬼？两者的差异又是什么呢？
这个PWM和SPWM到是什么鬼？两者的差异又是
什么呢？
很多在购买MP3芯片的时候，都很容易看到xx芯片非PWM输出或许SPWM输出，那幺这个PWM和SPWM到是什幺鬼？两者的差异又是什幺呢？
PWM
PWM即脉冲宽度调制，是英文“Pulse Width ModulaTIon”的缩写，简称脉宽调制，是运用微处理器的数字输出来对模仿电路进行操控的一种十分有用的技能，广泛运用在从丈量、通讯到功率操控与改换的许多范畴中。
原理：随着电子技能的开展，呈现了多种PWM技能，其中包含：相电压操控PWM、脉宽PWM法、随机PWM、SPWM法、线电压操控PWM等，而在镍氢电池智能充电器中选用的脉宽PWM法，它是把每一脉冲宽度均相等的脉冲列作为PWM波形，经过改动脉冲列的周期能够调频，改动脉冲的宽度或占空比能够调压，选用恰当操控办法即可使电压与频率和谐改动。
能够经过调整PWM的周期、PWM的占空比而到达操控充电电流的意图。
长处PWM的一个长处是从处理器到被控体系信号都是数字办法的，无需进行数模变换。
让信号坚持为数字办法可将噪声影响降到最小。
噪声只要在强到足。
脉冲宽度调制(PWM)大学毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：脉冲宽度调制（PWM）文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14外文原文Pulse-width modulationPulse-width modulation (PWM)is a modulation technique that conforms the width of the pulse, formally the pulse duration, based on modulator signal information. Although this modulation technique can be used to encode information for transmission, its main use is to allow the control of the power supplied to electrical devices, especially to inertial loads such as motors. In addition, PWM is one of the two principal algorithms used in photovoltaic solar battery chargers,[1]The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast pace. The longer the switch is on compared to the off periods, the higher the power supplied to the load is.The PWM switching frequency has to be much faster than what would affect the load, which is to say the device that uses the power. Typically switchings have to be done several times a minute in an electric stove, 120 Hz in a lamp dimmer, from few kilohertz (kHz) to tens of kHz for a motor drive and well into the tens or hundreds of kHz in audio amplifiers and computer power supplies.The term duty cycle describes the proportion of 'on' time to the regular interval or 'period' of time; a low duty cycle corresponds to low power, because the power is off for most of the time. Duty cycle is expressed in percent, 100% being fully on.The main advantage of PWM is that power loss in the switching devices is very low. When a switch is off there is practically no current, and when it is on, there is almost no voltage drop across the switch. Power loss, being the product of voltage and current, is thus in both cases close to zero. PWM also works well with digital controls, which, because of their on/off nature, can easily set the needed duty cycle.PWM has also been used in certain communication systems where its duty cycle has been used to convey information over a communications channel.HistoryIn the past, when only partial power was needed (such as for a sewing machine motor), a rheostat (located in the sewing machine's foot pedal) connected in series with the motor adjusted the amount of current flowing through the motor, but also wasted power as heat in the resistor element. It was an inefficient scheme, but tolerable because the total power was low. This was one of several methods of controlling power. There were others—some still in use—such as variable autotransformers, including thetrademarked 'Autrastat' for theatrical lighting; and the Variac, for general AC power adjustment. These were quite efficient, but also relatively costly.For about a century, some variable-speed electric motors have had decent efficiency, but they were somewhat more complex than constant-speed motors, and sometimes required bulky external electrical apparatus, such as a bank of variable power resistors or rotating converter such as Ward Leonard drive.However, in addition to motor drives for fans, pumps and robotic servos, there was a great need for compact and low cost means for applying adjustable power for many devices, such as electric stoves and lamp dimmers.One early application of PWM was in the Sinclair X10, a 10 W audio amplifier available in kit form in the 1960s. At around the same time PWM started to be used in AC motor control.Fig. 1: a pulse wave, showing the definitions of , and D.Pulse-width modulation uses a rectangular pulse wave whose pulse width is modulated resulting in thevariation of the average value of the waveform. If we consider a pulse waveform , with period ,low value , a high value and a duty cycle D (see figure 1), the average value of thewaveform is given by:As is a pulse wave, its value is for and for. The above expression then becomes:This latter expression can be fairly simplified in many cases where as. From this, it is obvious that the average value of the signal () is directly dependent on the duty cycle DFig. 2: A simple method to generate the PWM pulse train corresponding to a given signal is the intersective PWM: the signal (here the red sinewave) is compared with a sawtooth waveform (blue). When the latter is less than the former, the PWM signal (magenta) is in high state (1). Otherwise it is in the low state (0).The simplest way to generate a PWM signal is the intersective method, which requires only a sawtooth or atriangle waveform (easily generated using a simple oscillator) and a comparator. When the value of the reference signal (the red sine wave in figure 2) is more than the modulation waveform (blue), the PWM signal (magenta) is in the high state, otherwise it is in the low state.Time proportioningMany digital circuits can generate PWM signals (e.g., many microcontrollers have PWM outputs). They normally use a counter that increments periodically (it is connected directly or indirectly to the clock of the circuit) and is reset at the end of every period of the PWM. When the counter value is more than the reference value, the PWM output changes state from high to low (or low to high).[3]This technique is referred to as time proportioning, particularly as time-proportioning control[4]– which proportion of a fixed cycle time is spent in the high state.The incremented and periodically reset counter is the discrete version of the intersecting method's sawtooth. The analog comparator of the intersecting method becomes a simple integer comparison between the current counter value and the digital (possibly digitized) reference value. The duty cycle can only be varied in discrete steps, as a function of the counter resolution. However, a high-resolution counter can provide quite satisfactory performance.PWM sampling theoremThe process of PWM conversion is non-linear and it is generally supposed that low pass filter signal recovery is imperfect for PWM. The PWM sampling theorem[6] shows that PWM conversion can be perfect. The theorem states that "Any bandlimited baseband signal within ±0.637 can be represented by a pulsewidth modulation (PWM) waveform with unit amplitude. The number of pulses in the waveform is equal to the number of Nyquist samples and the peak constraint is independent of whether the waveform is two-level or three-level."Power deliveryPWM can be used to control the amount of power delivered to a load without incurring the losses thatwould result from linear power delivery by resistive means. Potential drawbacks to this technique are the pulsations defined by the duty cycle, switching frequency and properties of the load. With a sufficiently high switching frequency and, when necessary, using additional passive electronic filters, the pulse train can be smoothed and average analog waveform recovered.High frequency PWM power control systems are easily realisable with semiconductor switches. As explained above, almost no power is dissipated by the switch in either on or off state. However, during the transitions between on and off states, both voltage and current are nonzero and thus power is dissipated in the switches. By quickly changing the state between fully on and fully off (typically less than 100 nanoseconds), the power dissipation in the switches can be quite low compared to the power being delivered to the load.Modern semiconductor switches such as MOSFETs or Insulated-gate bipolar transistors (IGBTs) are well suited components for high efficiency controllers. Frequency converters used to control AC motors may have efficiencies exceeding 98%. Switching power supplies have lower efficiency due to low output voltage levels (often even less than 2 V for microprocessors are needed) but still more than 70–80% efficiency can be achieved.Variable-speed fan controllers for computers usually use PWM, as it is far more efficient when compared to a potentiometer or rheostat. (Neither of the latter is practical to operate electronically; they would require a small drive motor.)Light dimmers for home use employ a specific type of PWM control. Home-use light dimmers typically include electronic circuitry which suppresses current flow during defined portions of each cycle of the AC line voltage. Adjusting the brightness of light emitted by a light source is then merely a matter of setting at what voltage (or phase) in the AC halfcycle the dimmer begins to provide electrical current to the light source (e.g. by using an electronic switch such as a triac). In this case the PWM duty cycle is the ratio of the conduction time to the duration of the half AC cycle defined by the frequency of the AC line voltage (50 Hz or 60 Hz depending on the country).V oltage regulationMain article: Switched-mode power supplyPWM is also used in efficient voltage regulators. By switching voltage to the load with the appropriate duty cycle, the output will approximate a voltage at the desired level. The switching noise is usually filtered with an inductor and a capacitor.One method measures the output voltage. When it is lower than the desired voltage, it turns on the switch. When the output voltage is above the desired voltage, it turns off the switch.Audio effects and amplificationPWM is sometimes used in sound (music) synthesis, in particular subtractive synthesis, as it gives a sound effect similar to chorus or slightly detuned oscillators played together. (In fact, PWM is equivalent to the difference of two sawtooth waves with one of them inverted.[1]) The ratio between the high and low level is typically modulated with a low frequency oscillator. In addition, varying the duty cycle of a pulse waveform in a subtractive-synthesis instrument creates useful timbral variations. Some synthesizers have a duty-cycle trimmer for their square-wave outputs, and that trimmer can be set by ear; the 50% point (true square wave) was distinctive, because even-numbered harmonics essentially disappear at 50%. Pulse waves, usually 50%, 25%, and 12.5%, make up the soundtracks of classic video games.A new class of audio amplifiers based on the PWM principle is becoming popular. Called "Class-D amplifiers", they produce a PWM equivalent of the analog input signal which is fed to the loudspeaker via a suitable filter network to block the carrier and recover the original audio. These amplifiers arecharacterize d by very good efficiency figures (≥ 90%) and compact size/light weight for large power outputs. For a few decades, industrial and military PWM amplifiers have been in common use, often for drivingservo motors. Field-gradient coils in MRI machines are driven by relatively high-power PWM amplifiers.Historically, a crude form of PWM has been used to play back PCM digital sound on the PC speaker, which is driven by only two voltage levels, typically 0 V and 5 V. By carefully timing the duration of the pulses, and by relying on the speaker's physical filtering properties (limited frequency response, self-inductance, etc.) it was possible to obtain an approximate playback of mono PCM samples, although at a very low quality, and with greatly varying results between implementations.In more recent times, the Direct Stream Digital sound encoding method was introduced, which uses a generalized form of pulse-width modulation called pulse density modulation, at a high enough sampling rate (typically in the order of MHz) to cover the whole acoustic frequencies range with sufficient fidelity. This method is used in the SACD format, and reproduction of the encoded audio signal is essentially similar to the method used in class-D amplifiers.中文翻译一、脉冲宽度调制脉冲宽度调制（PWM），是一种在一定的脉冲持续时间内，基于调制信号来追踪所希望达到的脉冲宽度的调制方式。
十脉波宽度调变(PulseWidthModulation)
第十一章脈波寬度調變(Pulse WidthModulation)11-1、簡介脈波寬度調變（Pulse Width Modulation，(PWM)）基本的控制原理是根據輸入信號的大小，調整輸出脈波的寬度，而此脈波的頻率為固定。
如圖11-1(a)所示是一個正弦波的正半週波形，若取樣點如圖11-1(a) 所示，根據取樣值的大小，來決定脈波的寬度。
因此就可以得到如圖11-1(b)所示的脈衝列。
圖11-1：PWM基本控制原理PWM的輸出時序如圖11-2所示。
PWM輸出有兩個名詞需要注意到：Period和Duty Cycle。
當PWM輸出由此次變High到下一次變High的時間稱為Period；而PWM輸出保持在High(1)的時間除以Period，稱呼它為PWM的Duty Cycle。
圖11-2：PWM輸出時序圖11-2、 ET44M210的PWMET44M210微控制器提供兩組16位元解析度的PWM輸出。
PWM0是連接到PORT A 的Bit 7，PWM1是連接到PORT C的Bit 5。
因為ET44M210微控制器的PWM輸出是16位元的解析度，因此Duty Cycle是由2個暫存器所決定：Duty Cycle High Byte(DT0H；DT1H)和Duty Cycle Low Byte(DT0L；DT1L)。
DT0H：DT0L是針對PWM0所設定的暫存器；DT1H：DT1L是針對PWM1所設定的暫存器，統稱為DTX。
另外ET44M210也定義了一組16位元的Duty Cycle Latch暫存器，Duty Cycle Latch 暫存器是由2個暫存器所決定：Duty Cycle Latch High Byte(DL0H；DL1H)和Duty Cycle Latch Low Byte(DL0L；DL1L)。
DL0H：DL0L是針對PWM0所設定的暫存器；DL1H：DL1L 是針對PWM1所設定的暫存器，統稱為DLX。
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毕业设计外文资料翻译学院：专业：姓名：学号：外文出处： Home Power #75·February/March2000 (用外文写)24.437 Power Electronics附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文自制程序脉冲幅宽调节——应用于12-24伏G．弗勒斯特库克宽幅脉冲调节器(PWM)可以作为调光器使用，还可以作为直流电机调速器。
这里所描述的设备可以控制几安培的直流电流。
该电路系统可以用于调节12-24伏内的微小变化。
此设备已被用于控制汽车尾灯亮度，以及电脑电源控制的小型直流风扇的转速。
脉冲幅宽调节一个PWM电路的工作原理是形成一系列占空比率可控的直流脉冲方波。
在平均时间内可以有0-100%的不同变化。
这样，就能把量化的电力传送到负载。
PWM电路相比于电阻功率控制器上的的主要优点是效率更高。
在PWM的50%的水平时，将使用全部功率的50%，几乎将所有这些都转移到负载。
而在电阻功率控制器的50%水平时，将消耗约全部功率的71%；50%的功率转移到负载，另外21%的能量浪费到了加热电阻上。
根据负载电流，通常PWM电路浪费的功率远低于1%。
它需要在连续恒定功率下运行，所以更多被用于高功率负载的效率提高。
优势能源再生系统中的关键是提高负载效率。
一个脉宽调制器的另一个优点是，有充分的脉冲电源电压，并且产生一个更容易克服电机内阻的更大的扭矩。
而一个电阻功率控制器对电机速度的控制会使电压减弱，这将导致电机反应延迟。
最后，在PWM电路，常见的小电位器可用于控制各种负载，而大型和昂贵的高功率可变电阻器必须要用电阻控制器。
缺点脉宽调制电路的主要缺点是增加了复杂性，和可能产生射频干扰（RFI）。
射频干扰会更少通过附近的负载控制器而通过短路线，而且在某些情况下，会通过额外的电源滤波线路。
该电路会产生调幅无线干扰，这些干扰在横跨负载电容（C3）的旁路形成，远离最近的引脚。
无线干扰容易在更远的距离漏检，需要额外的滤波。
可在串联直流电源输入汽车收音机的线路电抗。
但不能超过额定电流。
原理PWM电路的运行需要一个稳定运行的振荡器。
U1a和U1d形成一个正方形/三角形约400hz频率的波形发生器。
U1c产生的6伏参考电压用来作为振荡器的虚地。
让振荡器虚地是必要的，而不能由一个单电源的+/- 电压上的电源供电。
U1b上使用的是一个有线比较电路，是电路产生脉冲宽度可变的一部分。
一个比较器电路中，运算放大器的输出是真还是假，取决于运算放大器正输入高于负输入（真），反之亦然（假）。
U1b上引脚6收到来自R6，VR1，R7的阶梯可变电压。
这是对比于U1d引脚14的三角波。
当波形高于引脚6的电压，U1产生高输出，反之当波形低于6脚电压，U1产生低输出。
通过改变引脚6的电压高低来移动三角波，产生一个可变的脉冲宽度。
电阻R6和R7用来进行VR1的终点控制。
这些值允许该控件有一个全开全关的满量程电位器设定。
这些零件的值可能是多种的，以改变电位器的行为。
Q1是电源开关。
它的开关控制，通过接收端的门电压和脉冲宽度调制开关通过源漏电流路径的负载电流控制。
当Q1导通，它为一个负载提供了接地通路。
当Q1关断，负载是不接地的。
应小心以保证负载的不接地端子不会发生短路。
负载在任何时候都应对应电源电压的正极。
直流风扇控制器LED1是可选的，并给出一个可变的亮度，来响应脉冲宽度。
电容C3使开关波形平滑，并消除一些射频干扰。
二极管D1是一个续流二极管，它扭转了自感应电动机的负载电压。
在24V的模式，PWM电路将稳压器U2的24V转换到12V进行供电。
Q1控制着24V负载的接地，它和12V负载一样。
接线说明，请参阅有关的12或24V电路的原理图。
Q1在1安培的电流水平，无需散热片。
不过，如果控制更大的电流，需要大型散热片。
Q1可以被替换为更高级的电流控制设备，比如IRFZ34N。
所有的电流处理装置，开关S1、保险丝F1、和之间的场效应管、电源线、负载，应该小于能处理的最大电流。
为了延长场效应管的寿命，电路电流最好低于额定电流。
安全范围是最大限度的百分之八十。
如电机感性负载巨大的峰值额定电流就超过了对场效应管的保障范围。
考虑到最大电流时，超过了安全限度，大功率电机控制器需要额外的钳位电路来降低高电压的尖峰。
一般的做法是用场效应管上的D-S端子的稳压二极管。
这类电路信息超出了该文本的范围，请参照场效应管的制造商（国际整流器公司，）的数据表。
PWM原理图结构该电路的原型是建立在这样一个普通集成电路原版上，并使原版上的孔部分卡住电线。
一个成品电路版，是用来安装变速直流风扇的。
风扇安装在脉宽调节电路顶部一个小金属盒子里。
我在Linux操作系统上使用免费的电路设计软件CAD，设计了一个简单的印刷电路板。
该电路板印有一个在Techniks打印的Press-n-Peel的蓝膜到PostScript的激光掩膜。
把胶片熨到一个单双面覆铜箔的原板上。
将该电路板用氯化铁溶液蚀刻，母板模式如右图所示。
这个是影印在Press-n-Peel上的一片蓝膜。
电路板和零件布局可以从下载。
将电路板连接到电源和负载的零件进行焊接。
这种技术在短时间内生产工作板不错，但不适合大量的电路板的生产。
可替换的是，可以使用”dead-bug”这种焊接方式。
命名为”dead-bug”是由于电路板的外观与芯片和在任意角度穿在一起的部分位置。
这涉及到一块空白铜箔板，用五分钟的环氧树脂粘合一个绕IC插座的电路板，然后焊接所有对卷线引脚。
接地线可直接焊到铜版上。
必须要与此电路校准。
PWM的组件位置该PWM元件位置图是侧面显示的，对面板的另一面放焊料。
该电路板用12V电压的电路板。
它可用24V的线路为正负12V稳压器，和移动的直流负载在正端接24V电源。
用于电路板连接器CN1（引脚1是一个正方形标记）：1 VR1低2 VR1高3 +12V电源线4 VR1融合中心5 正负载6 备用接地7 负负载8 12V接地电源使用该电路可用于直流灯的调光器，小型马达的控制器，小型加热器的控制器。
它还可以成为一个太阳能驱动的电动机车的速度控制器。
我还从尝试过较大的电动机电路。
在理论上，它可以应用在自行车电机驱动系统上。
如果你想在本实验中使用，一定要有一个方便的紧急电源短接在FET开关上。
请记住通过直流电动机的脉冲电流会比平均电机额定电流大许多倍。
如果不能处理其规定的脉冲电流，场效应管将被击毁。
场效应管可以并联接入，以增加可通过的电流。
线材为12或24V按电路图接，电源连接到输入端，并连接到输出负载电路。
可千万不要任意地输出，或连接到输出端，如是电机的情况下，任何东西都不行。
转动电位器旋钮，负载应该显示出速度变化。
参考资料作者：克弗雷斯特库克，WBORIO，2910卡内基博士，博尔德，CO80303·cook@/g fc/ • PC Board PostScript files:/gfc/elect/solarcirc/pwm1/index.html部分：Jameco, 1355 Shoreway Rd., Belmont, CA 94002800-831-4242 or 650-592-8097传真: 800-237-6948 or 650-592-2503info@ • Digi-Key, PO Box 677, Thief River Falls,MN 56701-0677 • 800-DIGIKEY or 218-681-6674Fax: 218-681-3380 • sales@PCB Software • ftp://ftp.uni-ulm.de/pub/pcb/mirrorTechniks, Inc., PO Box 463, Ringoes, NJ 08551908-788-8249 • Fax: 908-788-8837 • 24.437电力电子正弦脉宽调制电压源逆变器的开关（见图1）可以按要求打开和关闭。
用最简单的方法，顶部的开关打开，如果每个周期打开和关闭，方波的波形结果只有一次。
但是，如果改进谐波的数据则在一个周期内可以形成多次打开关闭。
图1：简单的电压源逆变器在最直接的实现方式，所期望的输出电压生成是通过比较预期的参考波形与高频率三角’载体’波（调制信号）所描述的图2.根据信号电压是否大于或小于载体波波形，无论是正还是负的直流母线电压施加在输出。
注意，在此期间一个三角波周期的平均电压加到负载型成正比（假定不变），信号的振幅。
注意,经过一段时期一个三角形波,平均电压的负荷是成正比的幅值的信号(假定常数)在这个时期。
由此产生的方波包含在它的低频率元件所需波形的复制，具有较高频率分量在一个载波频率接近的频率的福祉。
注意，均方根平方的交流电压波形值仍相等的直流母线电压，由于PWM使得总谐波不失真。
谐波成分只是转移到更高的频率范围，并且由于电感的交流系统自动地过滤。
当调制信号为正弦波的振幅Am，和三角载波的振幅Ac的比Am/Ac是已知的调制指数。
注意，控制调制指数为施加控制输出电压幅值。
具有足够高的载波频率（参见图3得出fc/fm=21 and t=L/R=T/3；T=基础时期），由于感性元件的存在高频成分明显不传播到交流网络（或负载）。
然而，由于较高的载波频率，开关较多从而在每个周期不增加功率损耗。
电力系统的应用通常在2-15kHz的开关频率范围被认为是足够的。
此外，在三相系统中，建议使用使所有三个波形对称。
图2：主要的脉宽调制图3：SPWM的fc/fm=48，L/R=T/3注意，这个过程很适合。
因为在图4中有三角波其中有没有交际的载体作为信号周期。
然而，这种“过调制”在一定量往往是允许获得更大的交流电压，使电压频谱呈现稍差。
注意，fc/fm使用一个额外的比率，波形是反周期超过360度的对称。
随着偶数阶谐波，特别小的直流元件。
因此一个单相逆变器的不推荐用偶数，特别是fc/fm额外比率。
SPWM的频谱：虽然SPWM波形已在几个数量相电压波形的谐波，比其他有根本优势，是因为当n=fc/fm，n和n正负2 。
这是经济脆弱性，在图5削弱了频谱对n=15和m=0.8 。
请注意，如果其他两个阶段产生的，但除了在相同阶段120o，先电压不会有任何。
因此它选择是明智的。
正如当时占主导地位的谐波将被淘汰。
它是由图5b自明的，占主导地位的第15谐波，图5a有效地消除了线路电压。
选择3的倍数也方便，则相同的特里安奇异波形可作为承运的所有三个阶段，可以使其在硬件上简化。
这是容易看到的，当E是输出电压信号的均方根，(pwm(θ))^2=E^2是直流母线电压。
这是严格的相电压谐波。
然而，问题谐波的转移较高，从而使过滤更加容易。
通常情况下，进行过滤通过自然高阻抗负载的特点。