【正文】 西安理工大學(xué)本科生畢業(yè)設(shè)計(jì)（論文 ） 第 23 頁 第 4 章 總結(jié) 這 次畢業(yè)設(shè)計(jì)我做的大功率脈沖變換器的高頻化研究。最后還學(xué)習(xí)到了關(guān)于 FPGA 的許多知識(shí)，最主要的是對(duì) FPGA的研究以及對(duì)于如何產(chǎn)生高精度的 PWM波，本文利用了一種數(shù)字“抖動(dòng)”的方法，其原理是基于輸出電壓平均值的原理，還有根據(jù)其實(shí)現(xiàn)框圖來完成相應(yīng)的編程并 且在 QuarterII 軟件內(nèi)實(shí)現(xiàn)仿真，通過這個(gè)過程也讓自己明白了以前做的設(shè)計(jì)過于理想化，在設(shè)計(jì)過程中對(duì)現(xiàn)狀和現(xiàn)實(shí)的根據(jù)太少，比如我所配置的 PWM波的頻率只有 500010000之間進(jìn)行波動(dòng)，而現(xiàn)實(shí)生活中很多都是有著幾萬甚至十幾萬的頻率要進(jìn)行研究。同時(shí)在這次畢業(yè)設(shè)計(jì)中遇到了很多的麻煩，最難的莫過于 FPGA的編程過程了，大量的新語言都需要自己去慢慢學(xué)習(xí)，最終在還是一點(diǎn)一點(diǎn)的攻克了下來。比如缺乏綜合應(yīng)用專業(yè)知識(shí)的能力，對(duì)材料的不了解，對(duì)具體設(shè)計(jì)涉及到的規(guī)范要求的不熟悉等等，需要在做的過程中需要去不斷的翻閱相關(guān)的資料和書籍，這降低了自己的速度和設(shè)計(jì)的進(jìn)程，但這個(gè)過程對(duì)我來說是對(duì)自己知識(shí)的不足處的一個(gè)很好的補(bǔ)充和對(duì)已學(xué)過知識(shí)的一個(gè)鞏固。通過這樣的一個(gè)自己從開始到結(jié)束全程自己參與的設(shè)計(jì)來說對(duì)知識(shí)的了解和掌握是純理論的學(xué)習(xí)遠(yuǎn)遠(yuǎn)達(dá)不到的效果。 田 晨：大功率脈沖變換器高頻化技術(shù)研究 第 24 頁 第 5 章 致謝 歷時(shí)將近兩個(gè)月的時(shí)間終于將這篇論文寫完，在論文的寫作過程中我遇到了無數(shù)的困難和障礙，都在同學(xué)和老師的幫助下度過了。陳桂濤老師 嚴(yán)謹(jǐn)?shù)闹螌W(xué)態(tài)度、淵博的學(xué)術(shù)知識(shí)、誨人不倦的敬業(yè)精神以及 寬容的待人風(fēng)范使我獲益頗多， 老師平時(shí)加強(qiáng)畢業(yè)設(shè)計(jì)的輔導(dǎo)，我們還可隨時(shí)找老師進(jìn)行答疑，老師為方便我們聯(lián)系，把電話號(hào)碼和 Email地址留給了我們，如果有什么事就可以及時(shí)得到解決，這樣問題不致堆積、也不會(huì)因此拖了進(jìn)度。非常感謝陳老師的支持。 最后 ，感謝這篇論文所涉及到的各位學(xué)者教授，本論文引用了數(shù)位學(xué)者的研究文 獻(xiàn)， 如果沒有各位學(xué)者的研究成果的幫助和啟發(fā)，我將很難完成本篇論文的寫作。 ll wait in the line for one hour to get a ticket, and another two hours at the site, to only see a tiny bit of the place due to the crowds. Last year, 428 million tourists traveled in China over the weeklong holiday in October. Traveling during this period is a matter that needs thorough preparation. If you are short on time to plan the uping Golden Week it may not be a bad idea to avoid some of the most crowded places for now. There is always a place so fascinating that everyone yearns for. Arxan is a place like this. The beauty of Arxan is everlasting regardless of the changing of four seasons. Bestowed by nature, its spectacular seasonal landscape and mountains are just beyond word. Arxan is a crucial destination for the remended travelling route, China Inner Mongolia Arxan — Hailar — Manzhouli. It is also the joint of the four prairies across the SinoMongolian border, where people gravitate towards the exotic atmosphere mixed with Chinese, Russian, and Mongolia elements. As a historic site for the Yitian Battle, Arxan still embodies the spirit of Genghis Khan. Walking into Arxan, you will be amazed by a kaleidoscope of geous colors all the year round the Spring azaleas blooming red in the snow, the Summer sea wavering blue in the breeze, the Autumn leaves painted in yellow covering volcanic traces, and the Winter woods shining white on the vast alpine snowscape. Hinggan League Arxan city is situated in the far eastern area of Inner Mongolia Autonomous Region. Its full name Haren Arxan means hot holy water in the Mongolian language. Arxan is a tourism city in the northern frontier with a blend of large forest, grand prairies, vast snowfield, heaven lake cluster, thermium, as well as volcanic cluster. It is a rare and unique ecotourism base filled with healthy sunshine, clean air and unspoiled green. Nestled close to the country39。s time for the wild fruits to ripe. The picturesque Arxan in Autumn is indeed a fairyland only exists in a dream that satisfies all your fantasies. If it rains heavily on Saturday night, some elderly Chinese will say it is because Zhinu, or the Weaving Maid, is crying on the day she met her husband Niulang, or the Cowherd, on the Milky Way. Most Chinese remember being told this romantic tragedy when they were children on Qixi, or the Seventh Night Festival, which falls on the seventh day of the seventh lunar month, which is usually in early August. This year it falls on Saturday, August 2. Folklore Story As the story goes, once there was a cowherd, Niulang, who lived with his elder brother 西安理工大學(xué)本科生畢業(yè)設(shè)計(jì)（論文 ） 第 27 頁 and sisterinlaw. But she disliked and abused him, and the boy was forced to leave home with only an old cow for pany. The cow, however, was a former god who had violated imperial rules and was sent to earth in bovine form. One day the cow led Niulang to a lake where fairies took a bath on earth. Among them was Zhinu, the most beautiful fairy and a skilled seamstress. The two fell in love at first sight and were soon married. They had a son and daughter and their happy life was held up as an example for hundreds of years in China. Yet in the eyes of the Jade Emperor, the Supreme Deity in Taoism, marriage between a mortal and fairy was strictly forbidden. He ordered the heaven troop to catch Zhinu back. Niulang grew desperate when he discovered Zhinu had been taken back to heaven. Driven by Niulang39。 Festival. In this day, girls will throw a sewing needle into a bowl full of water on the night of Qixi as a test of embroidery skills. If the needle floats on top of the water instead of sinking, it proves the girl is a skilled embroiders. Single women also pray for finding a good husband in the future. And the newly married women pray to bee pregnant quickly. Tradition transformed The love story of Niulang and Zhinu, and the Qixi Festival have been handed down for generations. Yet these ancient traditions and customs are slowly dying out. Many modern Chinese, particularly youngsters, seem to know more about St Valentine39。s Day. More and more young Chinese people begin to celebrate this day in a very similar way as that in western countries. Fewer people than ever will gaze at the heavens on Saturday to pick out the two stars shining bright on either side of the Milky Way, that is, if people even know on which day Qixi falls. There are ready reminders dotted about, in the form of big ads saying Sales on Chinese Valenti