【導(dǎo)讀】比高等突出優(yōu)點而得到廣泛應(yīng)用。本文介紹的GTRSPWM變頻調(diào)速系統(tǒng)是以。變器，使之輸出三相SPWM的波形，實現(xiàn)異步電機變頻調(diào)速。隨著變頻調(diào)速異步電動機在國內(nèi)外市場上日益擴大應(yīng)用。電動機系列、牽引變頻調(diào)速電動機系列等。從目前情況看，這些系列電動機能基。本滿足國內(nèi)市場的需求。為了適應(yīng)不同用途、不同工作條件和使用環(huán)境、不同工況等各種。要求，專用系列和改型系列變頻調(diào)速電動機產(chǎn)品不論現(xiàn)在和將來，都在迅速發(fā)展。作用下過早失效，從而引起絕緣擊穿故障。稱PWM技術(shù)）也日趨成熟。PMW交流變頻調(diào)速以其高效率、高功率因數(shù)、輸。將單片機應(yīng)用于交流變頻調(diào)速系統(tǒng)，可有效地避免傳統(tǒng)調(diào)速方案中的一些。使電動機輸出轉(zhuǎn)矩存在脈動分量，影響其穩(wěn)態(tài)工作性能。PWM脈寬調(diào)制是利用相當(dāng)于基波分量的信號波（調(diào)制波）對三角。載波進行調(diào)制，以達到調(diào)節(jié)輸出脈沖寬度的目的。PWM控制技術(shù)有許多種，并且還在不斷發(fā)展中。本課題設(shè)計主要介紹正弦波SPWM的變頻調(diào)。序列的周期以達到變壓和變頻的目的。

　　

【正文】 一天的樣子；或許是追溯過去，對自己那些近乎 偏執(zhí)的怪異信念的醒悟，這些天以來，思緒一直很凌亂，在腦海中不斷糾纏?？傆X得自己自己似乎應(yīng)該去做點什么，或者寫點什么。二十年的人生軌跡深深淺淺，突然就感覺到有些事情，非做不可了。 The end of our life, and can meet many things really do? 而窮盡我們的一生，又能遇到多少事情是真正地非做不可？ During my childhood, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional。 Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isn39。t really grow up, it seems is not so important。 Then in high school, think don39。t want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already can39。t remember his appearance. 童年時，覺得壓歲錢和新衣服是過年必備，但是隨著年齡的推進，會越來越發(fā)現(xiàn)，那些東西根本就可有可無；初中時，以為要有一場暗戀才意味著真正的成長，但三年過去后，自己心平氣和的 寫同學(xué)錄的時候，突然就發(fā)現(xiàn)是不是真正的成長了，好像并沒有那么重要了；然后到了高中，覺得非要吐露出自己的心聲才能為高中生涯里的懵懂情愫劃上一個句點，但畢業(yè)晚會的時候最終還是被梗塞在了咽喉，后來再次站在他曾經(jīng)揮汗如雨的球場，看著他投過籃球的球框時，突然間發(fā)現(xiàn)自己已經(jīng)想不起他的容顏。 Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time. 原來，這個世界上，對某個事件能產(chǎn)生化學(xué)反應(yīng)的，除了非做不可的堅決，還有，時間。 A person39。s time, your ideas are always special to clear. Want, want, line is clear, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection, or is a selfrighteous spiritual. 一個人的時候，自己的想法總是特別地清晰。想要的，不想 要的，界限明確，好像沒有什么可以撼動自己。也曾經(jīng)好像已經(jīng)下定了決心去做某件事，但更多的時候是最后又打起了退堂鼓。嫌惡過自己的怯懦，最終卻發(fā)現(xiàn)有很多 緣分 ，有很多錯過，好像冥冥之中真的已經(jīng)注定。那些曾經(jīng)所謂的非做不可，只是青蔥年華里自己給自己注射的一支強心劑，或者說，是自以為是的精神寄托罷了。 At the moment, the sky is dark, the air is fresh factor after just rained. Suddenly thought of blue plaid shirt。 Those were broken into various shapes of stationery。 From the corner at the beginning of deep friendship。 Have declared the end of the encounter that haven39。t start planning... Those years, those days of do, finally, like youth, will end in our life. 基于單片機控制的交流變頻調(diào)速系統(tǒng) 26 此刻，天空是陰暗的，空氣里有著剛下過雨之后的清新因子。突然想到那件藍格子襯衫；那些被折成各種各樣形狀的信紙；那段從街角深巷伊始的友誼；還有那場還沒有開始就宣告了終結(jié)的邂逅計劃 …… 那些年那些天的非做不可，終于和青春一樣，都將在我們的人生中謝幕。 Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our daytoday weather lives. It will climb higher than the tip of Mount Everest ( miles/ kilometers), drifting even higher than the cruising altitude of mercial airliners ( miles/ kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence. The supersonic descent could happen as early as Sunda. The weatheThe balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform. Below, the Earth bees the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, he39。ll be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jump When he jumps, he is expected to reach the speed of sound 690 mph (1,110 kph) in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him pletely. If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it39。s not needed. Instead, he plans to deploy 基于單片機控制的交流變頻調(diào)速系統(tǒng) 27 his 270squarefoot (25squaremeter) main chute at an altitude of around 5,000 feet (1,524 meters). In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds. Even if everything goes as planned, it won39。t. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters). cause there