dc shift 中文意思是什麼
dc shift
解釋
直流漂移-
A novel high - power pollution - free smps is presented in this paper, which accomplishes simultaneously the goal of soft - switching pwm, the input / output isolation, the output voltage regulation and three - phase pfc with a single - stage power processor and simple pseudo - phase - shift control circuit. therefore, compared with the normal two - stage system, the single - stage power supply has simpler structure, lower cost, higher efficiency and easier to control. the proposed smps can be used in the three - phase power system, and can output high power over kw - order and input / output ( i / o ) isolation dc power supply
本文提出的新型無污染大功率開關電源正是採用三相三線制輸入電源，利用單級偽相移零電壓零電流開關脈寬調制（ pps - zvzcs - pwm ）全橋變換器完，成功率因數校正（ pfc ）和輸出電壓快速調節、隔離的雙重功能，並且該變換器開關管在零電壓或零電流下通斷，顯著的減小了emi 。 -
In this thesis, the tradition phase - shift full - bridge zvs dc / dc converter are analyzed, and then a new dc / dc full - bridge converter employing switches clamping in secondary side of transformer is proposed, and the converter employing saturable inductor clamping are studied, and zvs ( zero - voltage - switching ) can be easily achieve by experiment validate
本文分析了一些傳統的移相全橋軟開關變換器，提出了開關管箝位dc dc全橋變換器拓撲方案，並對飽和電感器箝位dc dc全橋變換器進行了研究，並進行實驗驗證，從而解決了開關管的零電壓開關問題。 -
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。 -
In the end we have made a 50v / 10a full - bridge pwm dc / dc converters based on an improved circuit topology of full bridge phase shift zvs pwm converter. it can achieve zvs from no load to full load in virtue of an assistant commutation inductor
最後，構造了一個改進的全橋移相zvsdc dc變換器拓撲，在此基礎上研製了50v 10a通訊用全橋移相開關電源，該電源藉助于輔助換流電感，在空載到額定負載范圍內均可實現zvs 。 -
The sem and the pl observation showed that the surface of porous silicon prepared by pulsed etching was more uniform and the si particles were smaller. the intensity of pl formed by pulsed etching method was enhanced and the peak had blue shift comparing that formed by dc electrochemical etching method. at the same time, it was observed that the smaller the dimension of the porous silicon, the broader energy gap of the porous silicon
採用脈沖和直流電化學腐蝕兩種方法制備多孔硅，對這兩種方法制備的多孔硅樣品進行掃描電鏡和熒光光譜的測量，發現脈沖腐蝕制備的多孔硅樣品比直流腐蝕制備的多孔硅樣品表面均勻、顆粒尺寸小、發光強度大，而且發光峰位有明顯的藍移現象。 -
However these converters become more complicate. phase - shift zvs technique has been used in bidirectional dc / dc converters since it can realize zvs for all switches without auxiliary switches. however when the amplitude of input voltage is not matched with that of output voltage, the current stresses and rms currents of the converters become higher, in addition the converters can not achieve zvs under light - load condition
諧振、準諧振或多諧振技術方案，變換器的電壓電流應力較高，變頻控制增加了濾波器設計的難度；能量緩沖吸收電路或有源鉗位電路方案，由於需要增加多個額外輔助元件，增加了變換器的復雜性；全橋相移技術方案，由於主電路無需增加額外元件，只需利用相移控制，即可實現軟開關，因此引起關注。 -
The main works are organized as follows : based on the switching function method and time domain simulations, the small disturbance transfer a characteristic through the converter is analyzed. because of the modulation effect of the converter, the small disturbance in the shaft of turbine generator will induce ac voltage component with the same frequency as the disturbance on the dc side. and the resulted ac current on the dc side will have the similar frequency shift when transfers to the stator of the generator
主要內容包括： （ 1 ）基於開關函數法和模擬分析，研究了機組轉子上次同步頻率的小擾動，在hvdc交直流兩側響應的頻率特性- - - -轉子上的小擾動經直流換流器調制后，將會在系統直流側感應出與擾動同頻率的電壓分量；直流側電流擾動反映到交流定子側，也將發生頻率偏移。 -
However, these converters become more complicate. phase - shift bi - directional dc - dc converter is attractive since it operates with fixed frequency, has small voltage and current stress and can realize zvs without auxiliary switches
相移控制雙向dc - dc功率變換器因具有功率器件電壓，電流應力小，定頻工作和無須增加輔助器件即可實現功率器件的零電壓開關條件等優點而受到關注。
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