逆變分量 的英文怎麼說
中文拼音 [nìbiànfēnliáng]
逆變分量
英文
contravariant component-
Firstly, chromatism analysis and wavelet transform are used for color image compression coding. in this method, one of the three color components of a color image ( for example the g component of a rgb color image ) is coded using wavelet transform, and the chromatism between g and other two color components rg = r - g, bg = b - g is coded respectively using chromatism analysis. during decoding, g ~ is first reconstructed using wavelet inverse transform and inverse quantisation, and rg, bg are reconstructed using chromatism analysis inverse transform ; then r, b are calculated by r = g + rg and b = g + bg respectively
其一是應用色差分析和小波變換對彩色圖象進行壓縮編碼,該方法是對彩色圖象的三個色彩分量之一,如rgb圖象的g進行小波變換編碼,而對g與另兩個色彩分量的差值(即rg = r - g和bg = b - g )進行色差分析編碼,解碼則是通過反量化和小波逆變換得到g ^ ,通過色差分析的逆變換得到兩個重構的色差rg ^和bg ^ ,再算出r ^ = g ^ + rg ^ 、 b ^ = g ^ + bg ^ ,最後由r ^ 、 g ^ 、 b ^重構圖象。Every vector can be resolved into covariant or into contravariant components.
每個矢量都可以分解成協變分量或逆變分量。The spectral analysis of non - orthogonal functions cannot be obtained by orthogonal integration method. only the spectral analysis of some particular non - orthogonal functions can be realized by integral transformation. thus, the concept of reflection matrix is proposed and the mirror symmetry of spectral analysis for non - orthogonal function is revealed. any element functions whose reflection matrix can be obtained possesses its inverse element function. the spectral vector corresponding to an element function possesses its inverse spectral vector corresponding to the inverse element function. by reflection matrix the mapping relation of element function pair and spectral vector pair can be established. spectral analysis of non - orthogonal functions can be obtained with this symmetry by using the integration method as in the case of orthogonal functions, instead of calculating the inverse matrix as usual. so a convenient and practical method for spectral analysis of non - orthogonal functions is offered
非正交函數不能利用正交積分來實現譜分解.僅有某些特殊的非正交函數可以通過積分變換實現譜分解.本文提出了反射陣的概念,揭示了非正交函數譜分析的鏡像對稱性.任何能夠建立起反射陣的元函數存在著它的逆元函數,並且任何基於該元函數的譜向量同時也存在著基於逆元函數的逆譜向量.元函數對與譜向量對通過反射陣建立映射關系.利用這種對稱性,非正交函數可以象正交函數一樣使用積分方法獲得譜分解結果,而不必使用求解逆陣的方法,從而為非正交函數的譜分解提供了便捷、實用的方法At the same time, the control circuit must realize power regulating of the rectifying circuit and the inverter circuit and keep some parameters impervious to the interferer. this paper has researched high frequency solid induction heating power supply
同時,控制電路必須對整流電路、逆變電路等系統主電路部分進行功率控制,使在各種擾動下維持系統各參量不偏離其設定值。The study has completed the design of two - phase inverter and made up of the two - phase inverter - motor system for experimental use it is a variable frequency adjustable speed system with a open - loop control of rotational speed, which consists of voltage - controlled oscillator circulating assign device inverter circuit and two - phase induction motor a accurate mathematical model is set based on the whole system, and simulator program of dynamic and steady condition is established, which is used to calculate the dynamic and steady performance by kron and symmetrical coordinate converter by simulator calculation and experimental research with specific parameter of the system, a comparison is made between predicted and experimental characteristics, experimental measurements are shown to compare closely with corresponding theoretical result it is compared with some variable frequency adjus table speed system comprising inverter and single - phase induction motor from the system efficiency torque pulsation and the effect of two - phase inverter capacitance based on the conclusion, harmonic cancellation pulse width modulation control of a two - phase inverter - fed induction - motor drive system is researched, which cancelled the low harmonic and improve the system performance
通過對電機的kron變換和對稱分量變換,建立了系統較精確的數學模型,編制了系統動態及穩態運行的模擬計算程序分別計算系統的動態和穩態性能。通過對系統的具體參數進行了模擬運算和實驗研究,實驗和模擬結果進行比較,說明實驗和理論較為一致,並從系統效率、轉矩脈動及兩相逆變器電容的影響等方面與各種逆變器和單相異步電動機組成的變頻調速系統加以比較。在此基礎上,對兩相逆變器供電-異步電動機系統使用諧波抑制pwm控制進行了研究,由於減少了低次諧波,改善了系統性能。After the analysis of the state of converter switches, the voltage space vector is received. on the basis of hexagon stator flux trace method of traditional direct torque control, by changing the regulation of stator flux, hexagon and approximate round trace of stator flux can be got when using different voltage space vector. the fast regulation is realized when three - value regulator is used to adjust torque
通過對逆變器開關狀態的分析進而得到電壓空間矢量,並且論述了電壓空間矢量與轉矩和磁鏈之間的關系,使用兩點式調節方法對定子磁鏈進行調節,實現六邊形磁鏈軌跡和圓形軌跡方案,對轉矩採用三值調節器進行調節,以實現轉矩的快速調節。The time - domain measure technique of vector network analyzers base on inverse chirp - z transform
逆變換矢量網路分析儀時域測量技術Secondly, it sets up vector control model in simulink. and it realizes the control by two different ways, hysteresis and spwm
其次,在simulink中建立矢量控制的模擬模型,分別採用滯環和spwm的方式產生pwm信號控制逆變器。We discussed the four - legged inverter with space vector modulation ( svm ) to aim at three - phase four - line output ; we introduced the principle of three dimensions svm, and attained the related control scheme. with the illustration of 15kva vscf power inverter, we tested and verified that the inverter system under 3d svm control can realize the three phase four line output and linear voltage regulating
針對三相四線輸出的電源系統,對採用空間矢量控制的四橋臂逆變器進行了深入研究,對三維空間矢量調制方案進行了分析求解、模擬,並給出了適用於15kva變速恆頻電源變換器的解決方案,實現了變換器的三相四線輸出以及線性調壓。In this part, the high - frequency series inverter with resonant pole capacitor is introduced mainly. the current - exchanging processes of the inverter in different working modes are analyzed, how to reduce the switching loss is discussed, and the calculating methods of snubber capacitor c, factor angle switching frequency and pulse width pw are given in optimum switching process. and results of simulation and experiment verify the validity of theoretic analysis
接著重點研究了含有諧振極無損緩沖電容的逆變器,對其換流過程中的不同工作狀態進行分析,討論了如何減小逆變器的開關損耗,給出了最佳工作狀態下緩沖電容c 、感性角、開關頻率、觸發脈沖的脈寬pw的詳細計算方法,並通過大量的模擬和實驗波形證明了理論分析的正確性。Abstract : a continuity wave model is put forward for the dispersion processof liquid - liquid two - phase system, by coupling mass and momentum conservation equations of two - fluid model. the conditions that result in a dispersion choke and the weak instability of a dispersion process are derived from the model. the phenomena of catastrophic inversion and transitional inversion are explained. the effect of drop size distribution on the maximum volume concentration of a emulsion is predicted using the model. according to the theory herein, emulsion inversion is the regime transition of liquid - liquid system due to the instablity of a dispersion process. the effect of drop size distribution on the maximum volume concentration of a liquid - liquid emulsion only occurs in a certain range of weber numbers
文摘:以雙流體模型為基礎,通過質量守恆方程和動量守恆方程的耦合,提出了液-液兩相系中彌散傳質的連續波模型.由該模型得到彌散傳質過程阻塞和彌散傳質過程弱不穩定性產生的條件,計算了液滴尺寸及其分佈對乳化液極大堆砌分數的影響,解釋了劇變型乳化逆變和漸變型乳化逆變現象.研究結果表明,乳化逆變是由於彌散傳質過程的不穩定性而引起的懸浮體型態的改變,隨液滴尺寸多分散性的增大,極大堆砌分數增大;隨液滴平均尺寸的增大,多分散性對極大堆砌分數的影響減弱;當韋伯數足夠大時,液滴尺寸及其分佈對乳化液極大堆砌分數無影響In the chapter one, the primary principle of invert technique and its types have been dealt with. it also previews the development on high power invert technique in the future, as the result pointing out that the trend of the coming invert technique are high frequency, high power and highly intelligence
本文在第一章論述了逆變的基本原理與分類,並對大功率逆變技術的未來發展作了展望,指出了高頻化、高容量化、與智能化是其今後的發展趨勢。Chapter 4 focuses on the theory of voltage space vector pulse width modulation ( svpwm ) and its control strategy. a fast space vector modulation algorithm for 3 - level 3 - phase converter is also described in this chapter
首先,分析介紹了空間矢量控制在三相三電平逆變器控制中的應用,採用了一種簡單的空間矢量演算法,簡化了實時計算。Some research about sensorless control of induction motors in recent years has been introduced in chapter one. in chapter two, a field - oriented control system with current regulator and voltage source inverter ( vsi ) is presented firstly, which is proved in theory that the voltage feed - forward decoupler can be omitted, the good decoupled control properties of flux current and torque current is also validated by experiments with speed - sensor based on f240dsp real system
論文第二章從異步電機的基本數學模型入手,介紹了一種基於轉子磁場定向的帶電流內環控制的電壓型逆變器輸出閉環矢量控制結構,在理論上證明了該模型可省略電壓前饋解耦環節,採用f240dsp晶元構建的帶速度傳感器實驗系統驗證了其定子電流勵磁分量和轉矩分量有良好的解耦控制特性。Unlike inverters for general purpose, auxiliary inverters of subway vehicle have the characters of high power, wide range of high dc input voltage, entirely sealed electronic units and natural cooling. single pulse width modulation ( pwm ) technology is found to be optimal by comparing several different high power inverter technologies and is utilized in the 2 - channel staircase inverter discussed in this thesis
針對地鐵車輛輔助逆變電源的大功率、直流側輸入電壓高且變化范圍寬、輸出電壓穩定且波形質量高,電子部件全密封且要求自然冷卻的特點,分析比較了幾種大功率逆變器技術方案,選擇單邊脈寬調制階梯波合成逆變器為研究對象。In dtc system, the concept of space vector is introduced to analyze and control the ac motor, the electromagnetic torque and flux are calculated and controlled in the stationary coordinate, and the optimal pwm gating signals are generated to control the inverter to acquire high dynamic torque according to the output of the bang - bang regulators
直接轉矩控制採用空間矢量的概念來分析三相異步交流電動機的數學模型和各物理量,直接在靜止坐標系下計算與控制交流電動機轉矩和磁鏈,藉助于離散的兩點式調節產生pwm信號,直接對逆變器的開關狀態進行最佳控制,以獲得轉矩的高動態性能。Recurring to resynchronization marker, data partitioning and rvlc, video files with errors are dealt with. the article codes and decodes video source files with errors, computing every algorithm ' s psnr, comparing video pictures " subjective and objective quality
運用重同步標志( resyncmarker ) 、數據分離( datapartitioning )和可逆變長編碼( rvlc )對含錯的視頻文件分別做錯誤處理。以mpeg - 4錯誤恢復方法對糟糕視頻源文件編碼、解碼,計算該演算法的psnr ,比較視頻幀的主客觀質量。The performance of the electric vehicle is improved greatly in which the harmonic wave of output voltage, power loss and torque pulsation of the system are decreased by controlling the switch angles
它運用規則采樣法產生正弦脈寬調制波,通過開關角的控制抑制逆變器輸出電壓中的諧波分量,降低了電動機的損耗和轉矩脈動,使電動車的運行性能得到了較大改善。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。Switching loss and efficiency of the proposed resonant pole zvt three - phase pwm inverter are analyzed and discussed. results of calculation and testing of the prototype together with a hard - switching inverter with the same specification show that an improvement of 2 % ~ 3 % is obtained. based on the analysis of drawbacks of existing svpwm technique in resonant pole zvt three - phase pwm inverters, several improved svpwm methods are presented
對提出的諧振極零電壓過渡三相pwm逆變器的開關損耗和工作效率,進行了深入的分析和討論,並針對原理樣機進行了理論計算和實際測量,並與相同規格的硬開關三相逆變器進行了對比研究,結果表明,採用提出的軟開關技術的原理樣機的效率可以提高2 % 3 。分享友人