例句與造句

1. 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(jī)的數(shù)學(xué)模型,在此基礎(chǔ)上將異步電機(jī)的數(shù)學(xué)模型與直流電機(jī)的數(shù)學(xué)模型進(jìn)行了比較;然后介紹了矢量控制的基本原理,采用了一種改進(jìn)的轉(zhuǎn)子磁鏈電流型觀測模型;對三電平逆變器的電路拓?fù)?、工作原理、中點電位不平衡的機(jī)理及控制方法進(jìn)行了介紹,詳細(xì)分析了空間矢量脈寬調(diào)制策略。本文對異步電機(jī)的矢量控制與三電平逆變器之間的接口進(jìn)行了詳細(xì)的研究,包括:參考電壓矢量的形成、所落扇區(qū)與具體小三角形區(qū)域的判斷、送入逆變器之后的工作機(jī)理。在參考電壓矢量的合成時,選擇只包含p 、 o狀態(tài)的空間電壓矢量作為起始矢量,解決了扇區(qū)切換時的矢量突變問題。
2. It's difficult to find vector shift in a sentence. 用vector shift造句挺難的