Abstract: The DS1875 features a pulse-Width modulation (PWM) controller that can be used to control aDC-DC converter. The DC-DC converter can then be used to generate the high bias voltages necessaryfor avalanche photodiodes (APDs). This application note describes the operation of a boost converterthat uses the DS1875. Discussion covers the selection of the inductor and switching frequency, and theselection of components that improve the efficiency of the converter. Test data are presented.
標(biāo)簽： DC-DC 如何設(shè)計(jì) 高效率 轉(zhuǎn)換器
上傳時(shí)間： 2013-10-26
上傳用戶：lyson
數(shù)字控制的交流調(diào)速系統(tǒng)所選用的微處理器、功率器件及產(chǎn)生PWM波的方法是影響交流調(diào)速系統(tǒng)性能好壞的直接因素。在介紹了正弦脈寬調(diào)制(SPWM)技術(shù)的基礎(chǔ)上，設(shè)計(jì)了一種以8098單片機(jī)作為控制器，以智能功率模塊IPM為開(kāi)關(guān)器件的變頻調(diào)速系統(tǒng)。通過(guò)軟件編程，產(chǎn)生正弦脈沖寬度調(diào)制波形來(lái)控制絕緣柵雙極晶體管的導(dǎo)通和關(guān)斷，從而達(dá)到控制異步電動(dòng)機(jī)轉(zhuǎn)速的目的。實(shí)驗(yàn)結(jié)果表明，該系統(tǒng)可調(diào)頻率調(diào)電壓，穩(wěn)定度高，調(diào)速范圍寬，具有較強(qiáng)的實(shí)用價(jià)值 Abstract: AC variable speed with digital control systems used microprocessors， power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage， high stability， wide speed range， has a strong practical value.
標(biāo)簽： 8098 SPWM 單片機(jī) 變頻調(diào)速系統(tǒng)
上傳時(shí)間： 2013-11-14
上傳用戶：ynwbosss
A digital fi‘equeney meter designed with FPGA development software Q-~us 11 is introduced．The 1 Hz—l MHz input measured pulse signals of the digital ii‘equency meter can be used for measuring frequency，period，pulse width and duty ratio，etc．The test results stably display O71 3 seven—segment numeric tubes，and the measuring ranges may be switched over automatically．The measuring error is equal to or less than 0．1％．
標(biāo)簽： development introduced designed software
上傳時(shí)間： 2016-04-09
上傳用戶：stewart·
The PWM_1 project is a simple program for the STM32F103RBT6 using Keil MCBSTM32 Evaluation Board and demonstrating the use of PWM (Pulse Width Modulation) with Timer TIM4.
標(biāo)簽： Evaluation project program MCBSTM
上傳時(shí)間： 2013-12-25
上傳用戶：familiarsmile
s3c2410提供了5個(gè)16位的Timer（Timer0~Timer4），其中Timer0~Timer3支持Pulse Width Modulation—— PWM（脈寬調(diào)制 ）。Timer4是一個(gè)內(nèi)部定時(shí)器（internal timer），
上傳時(shí)間： 2013-12-16
上傳用戶：569342831
空間矢量脈寬調(diào)制(Space Vector Pulse Width Modulation) SVPWM的主要思想是:以三相對(duì)稱正弦波電壓供電時(shí)三相對(duì)稱電動(dòng)機(jī)定子理想磁鏈圓為參考標(biāo)準(zhǔn)，以三相逆變器不同開(kāi)關(guān)模式作適當(dāng)?shù)那袚Q，從而形成PWM波，以所形成的實(shí)際磁鏈?zhǔn)噶縼?lái)追蹤其準(zhǔn)確磁鏈圓。傳統(tǒng)的SPWM方法從電源的角度出發(fā)，以生成一個(gè)可調(diào)頻調(diào)壓的正弦波電源，而SVPWM方法將逆變系統(tǒng)和異步電機(jī)看作一個(gè)整體來(lái)考慮，模型比較簡(jiǎn)單，也便于微處理器的實(shí)時(shí)控制。 普通的三相全橋是由六個(gè)開(kāi)關(guān)器件構(gòu)成的三個(gè)半橋。這六個(gè)開(kāi)關(guān)器件組合起來(lái)（同一個(gè)橋臂的上下半橋的信號(hào)相反）共有8種安全的開(kāi)關(guān)狀態(tài). 其中000、111（這里是表示三個(gè)上橋臂的開(kāi)關(guān)狀態(tài)）這兩種開(kāi)關(guān)狀態(tài)在電機(jī)驅(qū)動(dòng)中都不會(huì)產(chǎn)生有效的電流。因此稱其為零矢量。另外6種開(kāi)關(guān)狀態(tài)分別是六個(gè)有效矢量。它們將360度的電壓空間分為60度一個(gè)扇區(qū)，共六個(gè)扇區(qū)，利用這六個(gè)基本有效矢量和兩個(gè)零量，可以合成360度內(nèi)的任何矢量。 當(dāng)要合成某一矢量時(shí)先將這一矢量分解到離它最近的兩個(gè)基本矢量，而后用這兩個(gè)基本矢量矢量去表示，而每個(gè)基本矢量的作用大小就利用作用時(shí)間長(zhǎng)短去代表。 在變頻電機(jī)驅(qū)動(dòng)時(shí)，矢量方向是連續(xù)變化的，因此我們需要不斷的計(jì)算矢量作用時(shí)間。為了計(jì)算機(jī)處理的方便，在合成時(shí)一般是定時(shí)去計(jì)算（如每0.1ms計(jì)算一次）。這樣我們只要算出在0.1ms內(nèi)兩個(gè)基本矢量作用的時(shí)間就可以了。由于計(jì)算出的兩個(gè)時(shí)間的總合可能并不是0.1ms(比這小)，而那剩下的時(shí)間就按情況插入合適零矢量。 由于在這樣的處量時(shí)，合成的驅(qū)動(dòng)波形和PWM很類似。因此我們還叫它PWM，又因這種PWM是基于電壓空間矢量去合成的，所以就叫它SVPWM了。
上傳時(shí)間： 2016-04-25
上傳用戶：bijiaohao22
基于TMS320F28035芯片為控制核心的空間矢量異步電機(jī)變頻器 我們?cè)O(shè)計(jì)的異步電機(jī)變頻調(diào)速器以TMS320F28035芯片為控制核心，通過(guò)輸出三相PWM波控制智能功率模塊IPM驅(qū)動(dòng)三相異步電機(jī)。我們使用空間矢量SVPWM算法，并對(duì)其進(jìn)行了優(yōu)化。采用檢測(cè)反電勢(shì)的方法省去了昂貴的光電編碼器，大大節(jié)省了成本。同時(shí)開(kāi)創(chuàng)性的研發(fā)了自動(dòng)根據(jù)運(yùn)行環(huán)境調(diào)節(jié)的自適應(yīng)變頻算法，使我們的變頻調(diào)速器可以在電網(wǎng)條件惡劣的鄉(xiāng)村山區(qū)工作，由此該變頻器已被一家民用水泵生產(chǎn)企業(yè)預(yù)訂。關(guān)鍵字 變頻器 TMS320f28035 IPM SVPWM In our design, the asynchronous machine inverter based on the chip of TMS320F28035 drives the three-Phase asynchronous machine by sending three-phase PWM waves to the IPM, which is short for the Intelligent-Power-Module. The SVPWM (space vector pulse width modulation) strategy is applied to our control algorithm and we optimize it mainly in two aspects. Firstly the inverter detects the speed by measuring the Back EMF instead of installing an expensive photoelectric encoder for costs reduction.
標(biāo)簽： tms320f28035 芯片
上傳時(shí)間： 2022-05-08
上傳用戶：zhanglei193
This demo shows the use of the PWM block in generating the pulse waveform whose duty cycle is changing regularly. The PWM waveform period is variable, while the width of the pulse remains constant.
標(biāo)簽： the generating waveform changi
上傳時(shí)間： 2014-01-15
上傳用戶：kr770906
This simple simulation of a pulse traveling down a parallel-plate guide makes a handy test code for initial experiments with boundary conditions. ToyFDTD3 adds some simple features to ToyFDTD1: A PMC boundary condition, a sinusoidal pulse source, and output tracking a single point in the mesh. Released 15 June 1999.
標(biāo)簽： parallel-plate simulation traveling simple
上傳時(shí)間： 2015-04-06
上傳用戶：stella2015
Setting and Changing Column Widths By default, all columns in a table start out with equal width, and the columns automatically fill the entire width of the table. When the table becomes wider or narrower (which might happen when the user resizes the window containing the table), all the column widths change appropriately.
標(biāo)簽： Changing Setting default columns
上傳時(shí)間： 2015-05-04
上傳用戶：璇珠官人
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