磁化逆轉 的英文怎麼說
中文拼音 [cíhuànìzhuǎn]
磁化逆轉
英文
reversal of magnetization-
The stability of electric power system has been being focused for a long time toprevent a power system from losing synchronism after sudden fault ， researchers have done much work and got many accomplishments this paper applied the direct feedback linearization ( dfl ) technique on the power system ， a strong nonlinear system simulation results by matlab proved this method efficiency main works and results are as follows ： this paper compared some existing methods in excitation control ， fast valve control and coordinated control respectively, analyzed the developments and actuality of nonlinear control research in brief, illustrated why ransient stability could be greatly improved by using the fast valve control in chapter 3 ， indicated the importance of coordinated control farther this paper introduced the inverse system theory, based on which ， discussed the dfl theory, pointed out which had consistency with the inverse theory, expanded the dfl theory combined the idiographic model equations ， made which adapt to the model of a single machine - infinite bus power system this paper referenced abundance articles and educed a set of equations ， which could describe the dynamical process of excitation and fast valve control for synchronous generators in the equations ， there were several very important parameters of power system - - rotor angle ( ) ， rotor speed ( ) ， generator q axis voltage ( eq ) ， transient voltage ( e ' q ) ， active power ( pe ) ， mechanical input power ( pm ) ， valve opening ( ) ， generator terminal voltage ( vt ) ， based on the model ， nonlinear coordinated controller and terminal voltage optimal controller have been designed by using the expanded dfl theory and lq optimal control theory the simulation results showed that the controller could keep power system transiently stable under the effects of a symmetrical 3 - phase short circuit fault ， which achieved better postfault regulation compared with another two routine methods ， one is the proportion excitation controller and proportion fast valve controller, the other is the proportion excitation controller and the optimal fast valve controller, which could exert good performance when met 1ittle disturbance either
在介紹逆系統理論的基礎上，詳細介紹了dfl理論，通過比較闡明了dfl理論其本質是逆系統方法的一類，並結合具體課題推導出的模型方程將dfl理論進行了擴展，使之適應于電力系統這個強非線性對象。通過參考大量的書籍文獻推導出一套實用的可將大型汽輪發電機勵磁與汽門綜合起來進行控制的模型方程，此模型方程涵蓋了電力系統中特別引人注目的幾個量- -轉子角、轉子轉速、發電機q軸電勢eq 、暫態電勢e ' q 、有功功率pe 、機械功率pm 、汽門開度、機端電壓vt ，在此基礎上建立了實用的電力系統簡化的數學模型，並將擴展的dfl理論應用於此模型系統，結合線性二次型最優控制理論設計出大型汽輪發電機的非線性綜合控制器及機端電壓最優控制器，通過模擬實驗與採用常規的按電壓偏差進行調節的比例式勵磁控制器+汽門比例控制及採用常規的按電壓偏差進行調節的比例式勵磁調節器和基於二次型性能指標設計的最優快控汽門（考慮發電機的飽和因素）進行了對比，證實了採用此種控制器可以有效地提高電力系統的暫態穩定性，並且在電力系統遭受小干擾時同樣具有良好的調節性能。Specific issues examined are : compensation for the variation of the stator resistance, the offset error of the dc bus voltage, the voltage error generated by the forward voltage drop the dead time of the switches, improvement of the steady state performance, and the speed sensorless control for the pmsm dtc drive system are of major concern in this thesis
定子電阻變化，直流母線電壓漂移，開關器件反向相電壓降、逆變器死區時間引起的電壓誤差的補償，提高系統穩態運行性能以及永磁同步電機直接轉矩控制的無速度傳感器運行方案等問題都是本文研究的重點。轉矩的快速響應是直接轉矩控制演算法的一個卓越的性能。The geologic record also shows that the strength of the magnetic field varies widely in time, and fluctuates wildly during field reversals, sometimes dropping to zero gauss strength ; ie : the field vanishes, disappears
地質記錄也表明磁場強度在時間上普遍變化，在磁場逆轉期間廣泛波動，有時降到零高斯強度；也就是：磁場消失不見了！The mathematical model of working process is built, and the theoretical analysis is accomplished, too. from the viewpoint of energy building and transform, another new method, named as additional resonant starting way, is presented. the principle of working and the structure of the circuit are described in detail
通過分析負載變化對串並聯逆變器啟動的影響，在預充初始能量研究的基礎上，從能量補償和能量轉換的觀點，提出了兩種新的啟動方法：負載充磁啟動方法和附加振蕩啟動方法。In dtc system, the concept of space vector is introduced to analyze and control the ac motor, the electromagnetic torque and flux are caculated and controlled in the stator reference frame, and the optimal pwm gating signas are generated to control the inverter according to the output of the bang - bang regulator. in this paper, the dtc system is designed based on dsp. a speed estimation method is derived detailedly and the sensorless speed close - loop control is conducted. in this system, there are some problems, such as flux drift and torque ripple. to resolve these problem, a modified flux caculation method and some measures such as speed lpf, torque slide filtering are adopted. the system performance is enhanced by these mersures
直接轉矩控制採用空間矢量的概念來分析異步電機的數學模型和控制其各物理量，直接在定子坐標系中計算和控制轉矩和磁通，藉助于離散的兩點式調節（ bang - bang控制）產生pwm信號，直接對逆變器的開關狀態進行優化控制，以獲得轉矩的高動態性能。本文採用dsp設計了直接轉矩控制系統，詳細推導了速度估計方法，進行了無速度傳感器的速度閉環控制。分享友人