A dither-free bias voltage and driver signal amplitude control technique for optical 8PSK generator

2014 ◽  
Vol 12 (s1) ◽  
pp. S10606-310609
Author(s):  
Yupeng Zhu Yupeng Zhu ◽  
Yanfu Yang Yanfu Yang ◽  
Bingyang Yan Bingyang Yan ◽  
Jiechang Zhong Jiechang Zhong ◽  
Yong Yao Yong Yao
Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2512
Author(s):  
Pierpaolo Dini ◽  
Sergio Saponara

This work presents an innovative control architecture, which takes its ideas from the theory of adaptive control techniques and the theory of statistical learning at the same time. Taking inspiration from the architecture of a classical neural network with several hidden levels, the principle is to divide the architecture of the adaptive controller into three different levels. Each level implements an algorithm based on learning from data and therefore we can talk about learning concepts. Each level has a different task: the first to learn the required reference to the control loop; the second to learn the coefficients of the state representation of a model of the system to be controlled; and finally, the third to learn the coefficients of the state representation of the actual controller. The design of the control system is reported from both a rigorous and an operational point of view. As an application example, the proposed control technique is applied on a second-order non-linear system. We consider a servo-drive based on a brushless DC (BLDC) motor, whose dynamic model considers all the non-linear effects related to the electromechanical nature of the electric machine itself, and also an accurate model of the switching power converter. The reported example shows the capability of the control algorithm to ensure trajectory tracking while allowing for disturbance rejection with different disturbance signal amplitude. The implementation complexity analysis of the new controller is also proposed, showing its low overhead vs. basic control solutions.


1970 ◽  
Vol 109 (3) ◽  
pp. 89-92 ◽  
Author(s):  
V. Bleizgys ◽  
A. Baskys ◽  
T. Lipinskis

The technique of voltage amplitude control of AC induction motor supplied by the frequency converter has been proposed. It is based on the observation of motor phase current amplitude value. The amplitude of motor supply voltage is controlled in real time in such a way that for given instant motor load and speed the phase current amplitude would be minimal, i.e. the efficiency of the motor would be maximal. The realization of this method of voltage amplitude control is less complicated as compared to vector control. It is enough to provide the continuous measurement of motor phase current amplitude and to find in the real time the amplitude of voltage, at which phase current amplitude is minimal. The proposed technique can be applied in the situations when the fast response of the motor supply voltage amplitude is not needed. The developed technique has been investigated experimentally using special test bench. Ill. 6, bibl. 11 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.109.3.178


2017 ◽  
Vol 31 (5) ◽  
pp. 514-521
Author(s):  
Qian Zhou ◽  
Yan Han ◽  
Shifeng Zhang ◽  
Xiaoxia Han ◽  
Ray C. C. Cheung ◽  
...  

Author(s):  
T. Ichinokawa ◽  
H. Maeda

I. IntroductionThermionic electron gun with the Wehnelt grid is popularly used in the electron microscopy and electron beam micro-fabrication. It is well known that this gun could get the ideal brightness caluculated from the Lengumier and Richardson equations under the optimum condition. However, the design and ajustment to the optimum condition is not so easy. The gun has following properties with respect to the Wehnelt bias; (1) The maximum brightness is got only in the optimum bias. (2) In the larger bias than the optimum, the brightness decreases with increasing the bias voltage on account of the space charge effect. (3) In the smaller bias than the optimum, the brightness decreases with bias voltage on account of spreading of the cross over spot due to the aberrations of the electrostatic immersion lens.In the present experiment, a new type electron gun with the electrostatic and electromagnetic lens is designed, and its properties are examined experimentally.


Author(s):  
T. Sato ◽  
S. Kitamura ◽  
T. Sueyoshl ◽  
M. Iwatukl ◽  
C. Nielsen

Recently, the growth process and relaxation process of crystalline structures were studied by observing a SI nano-pyramid which was built on a Si surface with a UHV-STM. A UHV-STM (JEOL JSTM-4000×V) was used for studying a heated specimen, and the specimen was kept at high temperature during observation. In this study, the nano-fabrication technique utilizing the electromigration effect between the STM tip and the specimen was applied. We observed Si atoms migrated towords the tip on a high temperature Si surface.Clean surfaces of Si(lll)7×7 and Si(001)2×l were prepared In the UHV-STM at a temperature of approximately 600 °C. A Si nano-pyramid was built on the Si surface at a tunneling current of l0nA and a specimen bias voltage of approximately 0V in both polarities. During the formation of the pyramid, Images could not be observed because the tip was stopped on the sample. After the formation was completed, the pyramid Image was observed with the same tip. After Imaging was started again, the relaxation process of the pyramid started due to thermal effect.


1969 ◽  
Vol 12 (1) ◽  
pp. 199-209 ◽  
Author(s):  
David A. Nelson ◽  
Frank M. Lassman ◽  
Richard L. Hoel

Averaged auditory evoked responses to 1000-Hz 20-msec tone bursts were obtained from normal-hearing adults under two different intersignal interval schedules: (1) a fixed-interval schedule with 2-sec intersignal intervals, and (2) a variable-interval schedule of intersignal intervals ranging randomly from 1.0 sec to 4.5 sec with a mean of 2 sec. Peak-to-peak amplitudes (N 1 — P 2 ) as well as latencies of components P 1 , N 1 , P 2 , and N 2 were compared under the two different conditions of intersignal interval. No consistent or significant differences between variable- and fixed-interval schedules were found in the averaged responses to signals of either 20 dB SL or 50 dB SL. Neither were there significant schedule differences when 35 or 70 epochs were averaged per response. There were, however, significant effects due to signal amplitude and to the number of epochs averaged per response. Response amplitude increased and response latency decreased with sensation level of the tone burst.


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