扇狀脈的 的英文怎麼說
中文拼音 [shānzhuàngmàide]
扇狀脈的
英文
fan nerved-
Its prominent cultural characteristics and historic values specifically manifests in the following aspects : the ancient city ' s water course which experiences long history, the natural fan - shape space pattern, the block landscape which contains commercial culture, the live edition of " the picture of shanghe in qingming ", the buildings of ming and qing dynasty which contains commercial culture, the commercial anecdote fables with legend characteristics
其鮮明的文化特色和歷史價值體現在：歷盡滄桑的古城水脈，自然的扇狀空間結構，蘊含商道文化的街區景觀， 《清明上河圖》的活版本，頗具商道文化色彩的明清建築，極具傳奇色彩的商道軼事傳說。Firstly, this paper introduces the asynchronous motor model, and compares it with the dc motor ’ s. then the paper studies the principle of vector control, and proposes an improved current model of rotor flux observer. this paper also studies the three - level inverter ’ s topology, working principle, the neutral - potential unbalance mechanism and its controlling strategy. the paper especially studies the svpwm in details. the interface between the vector control and the three - level inverter is studied in details, including the generation of reference voltage vector, its judging of the sector and triangular regions, and the working mechanism after it sent into three - level inverter. when synthesizing the reference voltage vector, select the vector which only includes p and o states as the starting vector, thus eliminate the vector shift problem when sector changes. this paper fully takes advantages of the powerful functions of matlab / simulink to set up the simulation model. this construction is very explicit. the simulation results verify the inverter voltage output is correct, the rotor flux is steady, the asynchronous motor ’ s dynamic and steady state performances and speed modulation are excellent
本文首先介紹了異步電機的數學模型，在此基礎上將異步電機的數學模型與直流電機的數學模型進行了比較;然後介紹了矢量控制的基本原理，採用了一種改進的轉子磁鏈電流型觀測模型;對三電平逆變器的電路拓撲、工作原理、中點電位不平衡的機理及控制方法進行了介紹，詳細分析了空間矢量脈寬調制策略。本文對異步電機的矢量控制與三電平逆變器之間的介面進行了詳細的研究，包括:參考電壓矢量的形成、所落扇區與具體小三角形區域的判斷、送入逆變器之後的工作機理。在參考電壓矢量的合成時，選擇只包含p 、 o狀態的空間電壓矢量作為起始矢量，解決了扇區切換時的矢量突變問題。Behind the advancing edge, the network is composed of bigger, well - defined vein with open spaces between them
質團扇形結構的後方呈網路狀，網路由一些粗大、明顯的菌脈組成。
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