zero frequency current 中文意思是什麼
zero frequency current
解釋
零頻電流-
A novel phase - shifted zero - voltage and zero - current switching pwm dc / dc full - bridge converter is presented in this thesis, which is based on the groundwork of summarization of the development of power electronics in recent years and lucubration in theoretical basis of modern high frequency soft switching power convert technique and analysis of operation principle, characteristic of the circuit and inherent drawbacks of the traditional phase - shifted zero - voltage switching pwm dc / dc full - bridge converter
本文在對近年來電力電子學科的發展高度綜述和對現代高頻軟開關功率變換技術理論基礎深入研究的基礎上，對傳統的移相控制zvspwmdc dc全橋變換器的工作原理、電路特性、存在的缺點進行了分析，在此基礎上提出了一種改進型的移相控制zvzcspwmdc dc全橋變換器。 -
Conventional hard switching technology has several flaws below : on and off loss, inductive off, capacitive on and diode recover problems. comparing with it, the loss of on and off decreases markedly, as the switches are on and off in zero voltage or zero current cases. and also the size of converter becomes smaller because of the higher of switching frequency
傳統硬開關技術由於存在開通關斷損耗大、感性關斷、容性開通、二極體反向恢復等問題，與之相比，軟開關技術在零電壓或零電流條件下導通，開關損耗明顯降低，加上開關頻率的提高使得變換器的體積得以減小，這也是軟開關技術受到青睞的原因。 -
The system is based on chopper constant current drive technique, according to the top level design idea, adopting advanced specical subdivision control integrate circuit and powerful function 80c196kc to organize the system frame, desiging the minimum system of single - chip microcomputer, multifunction i / o interface circuit, relay switch circuit, keyboard and display circuit, multifunction digital setting interface circuit and so on, utilizing the hso and hsi interface circuit which are owned by this single - chip microcomputer exclusively and its powerful command system to realize dual - degree switch control, automation orientation, automatically searching zero position, locking machine when stopping, frequency to set digitally, automatically adjusting speed through changing frequency, swithing subdivision or squarewave control, on the basis of above, the system also have the function of running according to the setting steps and the frequency, voltage and current to display through the led, etc
系統基於斬波恆流驅動技術，按照頂層設計思想，採用先進的專用細分控制電路和功能強大的80c196kc單片機來組建系統構架，設計了單片機最小系統、多功能i o介面電路、繼電器切換電路、鍵盤顯示電路和多功能數字設定介面電路等，利用該單片機獨有的hso和hsi介面及其強大的指令系統，實現了雙余度混合式步進電動機的余度切換控制、自動定位、零位自動搜索、停機鎖定、數字化頻率設定、自動調頻變速控制、細分方波切換控制，在此基礎上，該系統還設有按預置步運行、 led頻率電壓相電流顯示等功能。 -
Firstly, we analyze the transient and steady character of single phase high - impedance grounding fault. secondly, based on wavelet analysis on checking mutational signal and direction high frequency protection theory, utilizing zero sequence current and module current, this paper provides a new scheme including fault starting element, fault phase selection element, directional element and main criterion. this scheme can bear high impedance and is immune to system surge and frequency warp, which gets over the shortcoming of the lack of sensitivity
由於現有的保護方案無法快速有效地切除此類故障，本文在詳細分析了單相高阻接地故障的穩態和暫態特性的基礎上，從小波分析原理出發，利用小波變換檢測突變信號的原理，以零序電流、模電流等為研究對象，結合方向高頻保護的原理，設計了一套包含啟動元件、選相元件、方向元件、主保護的保護新方案。 -
The microprocessor is used to realize digital control as flip plus of the scr. the ic chip sa866ae of mitel company is utilized as the low frequency signal generator of the system. furthermore in the zero - current detection circuit, use the photocoupler gaalas ired and photo ic to detect zero - current, furthest shorten the commutating " died region ", prevent the current from distorting
設計中採用單片機控制可控硅的觸發脈沖，實現數字化控制，並利用mitel公司的三相pwm交流電機脈寬調制晶元sa866ae ，成功研製了交-交頻器中的低頻信號發生器裝置，效果良好；此外利用用光電檢測元件進行系統零電流的檢測，盡可能地縮短換相死區，防止電流發生畸變，成功地解決了原有低頻電源系統中存在的兩大難題。 -
One is to use fourier transformation to convert the source signal from time domain to frequency domain and to discard high frequency harmonious components upwards of 19 ( gb / t14953 - 93 d5. 3 demanding ), then to have static huffman coding to the quantized char array which is composed of reserved direct current component and basic wave and each high frequency " s amplitudes and angles. the other is to use discrete wavelet transformation to convert the source signal from time domain to frequency domain and to set the high frequency coefficients that its absolute value is smaller than the given threshold to zero, then to have dynamic huffman coding to the quantized char array which is composed of multiple, wavelet ' s level, datum length, low frequency coefficients and reserved high frequency coefficients. mass simulinks and analyses under the two circumstances have done to show that data compression ratio is small and the relative error is also small and within the permission of engineering and the compression problem can be solved in theory of measured datum of power system
第一種情況的壓縮方法為：採用傳統的傅立葉變換把原始信號從時間域變換到頻率域，舍棄20次及其以上的高次諧波成分（保證了gb / t14953 ? 93d5 . 3要求） ，然後對保留的直流分量、基波和各次諧波的幅值和相角數據量化后和量化時分別乘以的倍數系數構成一個數組，以字元形式保存，採用靜態huffman編碼對變換數據進行壓縮；採用離散小波變換把原始信號從時間域變換到頻率域，然後對分解得到的高頻系數進行閾值量化處理，對乘以的倍數系數、小波變換的階數、小波變換后的低頻、各級高頻以及原始數據長度、量化后的低頻系數以及保留的高頻系數大小、位置構成一個數組，以字元形式保存，採用動態huffman編碼對這個文件進行壓縮。 -
People can easily design the hysteresis current control hardware circuit, but the switching frequency is variable which makes us difficult the design the output filter, moreover the output waveform is not good. the space vector modulation techniques, by selecting the zero vector properly, it can reduce the harmonic content of the output voltage, so it has become a popular control method
滯環電流控制的硬體電路設計簡單，但存在開關頻率不固定，輸出濾波器設計困難，輸出波形質量差，空間矢量控制（ svm ）技術具有較高的電壓利用率，且通過對零矢量的合理控制可以降低諧波含量或降低開關損耗，因此是一種較好的控制方法。 -
By using phase shifting control between right bridge leg and left bridge leg, the output cy cloconverter commutating while the bi - polarity three - state high frequency ac volage from the input cycloconveter is zero, . and commutation overlap of the output cycloconverter and polarity selection of the input voltage, the leakage inductance energy and the output filtering inductance current are naturally commutated, and zvs switching of the output cycloconverter are realized, the surge voltage and surge current of the output cycloconverters are overcome
通過輸入周波變換器右橋臂相對左橋臂的移相，讓輸出周波變換器功率開關在輸入周波變換器輸出的高頻交流電壓為零期間進行換流，並藉助輸出周波變換器換流重疊和輸入電壓極性選擇，從而實現了變壓器漏感能量和輸出濾波電感電流的自然換流、輸出周波變換器的zvs開關，解決了輸出周波變換器固有的電壓過沖和環流問題。 -
" soft switching " is zero voltage switching or zero current switching, which the voltage ( or current ) of the switch varies by law of sine or quasi sine, the switch is on when its voltage reaches zero ( or switch is off when its current reaches zero ) by resonance. it makes switch loss is zero, so it can increase the operating frequency and raise power density, minimize the size of transformer and inductor
「軟開關」是指零電壓開關或零電流開關，它是利用諧振原理，使開關變換器的開關管電壓（或電流）按正弦（或準正弦）規律變化，當電壓過零時，使器件開通（或電流自然過零時，使器件關斷） ，實現開關損耗為零，從而提高開關頻率，減小變壓器、電感的體積。 -
The problem is much more critical when the inverter frequency is high. in a welding machine, the main circuit with the technology of the soft - switching is much idealer than the hard - switching. firstly of all, by the theory of the soft - switching, this paper relatively analysis the advantages of the soft - switching and, with the help of the simulation software pspice, analyzes the main circuit of the full bridge shift - phased zero voltage zero current ( zvzcs ) soft - switching
結合軟開關實現原理，本文首先對比分析了軟開關在提高效率、降低emi干擾等方面的技術優勢，通過pspice軟體模擬，分析研究了全橋移相零電壓零電流（ zerovoltagezerocurrent - - - - zvzcs ）軟開關電路，詳細介紹了該電路的軟開關實現過程，並給出了電路模型和關鍵元件的設計參數。 -
However input current distortion at the zero - crossing of the input voltage is a common problem in active pfc converters, and it becomes more serious as the line frequency is increased. the purpose of this thesis is to reduce the zero - crossing distortion of input current at high input frequency application
但有源pfc變換器存在輸入電流過零畸變的缺陷，並且隨著輸入頻率的升高而越來越嚴重，本文的工作就是針對解決高輸入頻率下嚴重的輸入電流過零畸變而展開的。
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