Autor: Cui, G. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Research on the influence of performance parameters on the super high speed permanent magnet synchronous generator external characteristic
Autorzy:: Qiu, H.
Tang, B.
Yang, C.
Cui, G.
Tematy:: external characteristic
influence degree
performance parameters
super high
speed permanent magnet generator; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/141228.pdf Link otwiera się w nowym oknie
Opis:: Super high speed permanent magnet generators (SHSPMG) usually operate at high frequency. The external characteristic of the SHSPMG under condition of high frequency operation is quite different from that of conventional generators. Therefore, it is necessary to study the external characteristic of the SHSPMG. Based on the finite element method, this paper studied the factors that affect the external characteristic of the SHSPMG. Combining the vector method and the finite element method, the external characteristic of the SHSPMG with the inductive load and the resistance load was studied. The variation law of the generator terminal voltage with the change of the load and current was obtained, and the key factors affecting the external characteristic of the SHSPMG were determined. The influences of the armature resistance, power factor, frequency and permanent magnet performance on the external characteristic of the SHSPMG were studied. The influence mechanism of different parameters on the generator external characteristic was revealed. The influence degree of each factor on the voltage regulation was determined. The conclusions can provide reference for the design and research of the SHSPMG.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: A Fast Classification Method of Faults in Power Electronic Circuits Based on Support Vector Machines
Autorzy:: Cui, J.
Shi, G.
Gong, C.
Tematy:: power electronics
fault diagnosis
wavelet transforms
support vector machines
directed acyclic graph
nearest neighbours; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/220922.pdf Link otwiera się w nowym oknie
Opis:: Fault detection and location are important and front-end tasks in assuring the reliability of power electronic circuits. In essence, both tasks can be considered as the classification problem. This paper presents a fast fault classification method for power electronic circuits by using the support vector machine (SVM) as a classifier and the wavelet transform as a feature extraction technique. Using one-against-rest SVM and one-against-one SVM are two general approaches to fault classification in power electronic circuits. However, these methods have a high computational complexity, therefore in this design we employ a directed acyclic graph (DAG) SVM to implement the fault classification. The DAG SVM is close to the one-against-one SVM regarding its classification performance, but it is much faster. Moreover, in the presented approach, the DAG SVM is improved by introducing the method of Knearest neighbours to reduce some computations, so that the classification time can be further reduced. A rectifier and an inverter are demonstrated to prove effectiveness of the presented design.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: Disparity servoing based fast autofocusing method for stereomicroscope
Autorzy:: Liu, Y.
Yu, M.
Cui, L.
Jiang, G.
Wang, G.
Fan, S.
Tematy:: autofocusing
stereomicroscope
stereomicroscopic images
disparity; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/174449.pdf Link otwiera się w nowym oknie
Opis:: A disparity servoing based fast autofocusing method is proposed for stereomicroscopes according to linear relationship between the disparity change in stereomicroscopic images and the move distance of a motorized translation stage. For a certain stereomicroscope, the calibration of a disparity range of clear images at each magnification is implemented offline. After that, the disparity of the stereomicroscopic image is used as an index to represent the sharpness of an arbitrary image. If the disparity does not satisfy the requirement, move steps and direction of a step motor are calculated by utilizing the linear relationship between the disparity change and the move distance of the stage. The iteration will be continued until the disparity of the captured stereomicroscopic image approximates to the clearest disparity. The experimental results show that the proposed method only requires a few iterations and less time to reach the focus position, and the disparity error is less than 0.5 pixel.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 4.

Tytuł:: A super depth of field height measurement based on local disparity
Autorzy:: Cui, L.
Liu, Y.
Yu, M.
Jiang, G.
Fan, S.
Wang, Y.
Tematy:: microscopes
binocular vision
local disparity map
depth of field (DOF)
height measurement; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/173522.pdf Link otwiera się w nowym oknie
Opis:: A super depth of field height measurement method is proposed to measure the object height with the optical stereoscopic microscope. The quasi-Euclidean epipolar rectification algorithm is utilized on the original stereoimage to obtain rectified stereoimages and calibrate two camera parameters. Then, feature points are obtained by the SURF (speed up robust feature) algorithm and their corresponding disparities are calculated. The disparity-depth of field curve is fitted by combining the step height values of a stepper motor. Moreover, through local disparity value got from feature points on the object, the relative shift height is calculated through regression analysis. Finally, according to binocular vision geometry, the thickness of the object can be calculated. Experimental results show that the measurement error in Z direction is from 1.51% to 7.71%, which indicates that the proposed method is able to measure the height of a microobject beyond depth of field within a tolerant error.
Dostawca treści:: Biblioteka Nauki