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이진국,이동희,안진우 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-
This paper presents a development of Switched Reluctance Motor (SRM) drive system for a hoist application. In the hoist system, smoothing start-up and braking are very important for a protection of goods. In order to improved a start-up and a stop performance of hoist system, the smoothing operation sequence of SRM using direct instantaneous torque control is proposed. The proposed Direct Instantaneous Torque Control (DITC) the instantaneous torque of SRM according to the switching sequence and hysteric band. In order to compare the reference and actual torque of SRM, pre-measured flux and torque look-up table are regulate used. The proposed SRM Drive system is verified by the simulation result.
이동희,이진국,안진우 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-
This paper proposes high speed SRM drive system for blower with a novel 4-level inverter and precise excitation position generator. In order to get a fast build-up and a demagnetization of excitation current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build- up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulations and experimental results.
Bending Fatigue Life Evaluation of Cu-Mg Alloy Contact Wire
Guo Zhen,석창성,김용석,Li Haochuang,구재민,이기원,권삼영 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.7
Contact wire is one of the most important components used to supply electricity to railway vehicles which equipped with apantograph. When the speed of electric vehicle is not as high as now, the failure of contact wire caused by friction and wear behaviorsof carbon strip/contact wire were considered more important. But the fatigue fracture become more and more important for the failureof contact wires on account of several fatigue fractures happened while the speed of electric vehicle increase continuously. A bendingfatigue tester simulating the working conditions of contact wires developed by Kang and etc has been used to evaluate the fatiguecharacteristic of pure copper and Cu-Sn alloy contact wires. In this study, this bending fatigue tester also is used to evaluate thefatigue characteristics of Cu-Mg alloy contact wire which developed for 400km/h high speed rail in Korea. Test result is alsocompared with the result of Kang's research on pure copper contact wire. Finally, in order to evaluate the fatigue life of contact wiresfor any mean stress, the relationships between plastic strain and fatigue life were abstained for two kinds of contact wires combinedthe FE analysis.
Partial Pole Assignment via Constant Gain Feedback in Two Classes of Frequency-domain Models
Guo-Sheng Wang,Guo-Zhen Yang,Guang-Ren Duan 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.2
The design problem of partial pole assignment (PPA) in two classes of frequency-domain MIMO models by constant gain feedback is investigated in this paper. Its aim is to design a constant gain feedback which changes only a subset of the open-loop eigenvalues, while the rest of them are kept unchanged in the closed-loop system. A near general parametric expression for the feedback gain matrix in term of a set of design parameter vectors and the set of the closed-loop poles, and a simple parametric approach for solving the proposed problem are presented. The set of poles do not need to be previously prescribed, and can be set undetermined and treated together with the set of parametric vectors as degrees of design freedom provided by the approach. An illustrative example shows that the proposed parametric method is simple and effective.
Zhen-Guo Lee,Seok-Kwon Jeong 전력전자학회 2005 JOURNAL OF POWER ELECTRONICS Vol.5 No.4
In this paper, a new speed sensorless induction motor scheme which can estimate rotor speed and rotor resistance simultaneously is presented. The rotor flux with a low frequency sinusoidal waveform is used to conduct on-line simultaneous estimation of the rotor speed and rotor resistance. Hence the proposed sensorless control method is robust to rotor resistance variations. Also, the control scheme has no current minor loop to determine voltage references. It contributes to good control performance at low speeds. Some simulation results supported by experiments are given to show the effectiveness of this method.
Fatigue Life Estimation of Cold Drawn Contact Wire
Guo, Zhen,Kim, Yong-Seok,Hong, Suk-Woo,Li, Hao-Chuang,Koo, Jae-Mean,Seok, Chang-Sung,Lee, Ki-Won,Kwon, Sam-Young Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.11
To evaluate the bending fatigue characteristics of contact wire, a stroke-based bending fatigue tester on contact wire has been developed by Kang et al. But this tester is too cumbersome and complicated. This paper is investigated with a new fatigue life estimation method based on Juvinall's method for estimation of S-N curve, which is widely used in steel structure, in order to estimate the bending S-N curve of cold drawn contact wire. First, the ultimate tensile strength and the axial tension fatigue test was performed with standard specimens, and the bending fatigue life for the cold drawn contact wire structure was predicted by using an improved S-N curve prediction method. Finally, the tested bending fatigue life of the structure was compared with the fatigue life estimated by the new method. As the result, the predicted bending S-N curve of the contact wire agreed fairly well with the experimental bending fatigue lives using the S-N curve and ultimate tensile strength of cold drawn material.
Experimental Study of Steel Plate Composite Shear Wall Units under Cyclic Load
Zhen Guo,Yingshu Yuan 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.3
A novel type of steel plate composite shear wall that was assembled by using a steel plate and precast cement-based concrete plate is presented in this paper. The steel plate shear wall, which differs from normal steel plate shear walls, was trilaterally constrained with an elastic restraint side. The precast concrete slab was designed to prevent steel plate buckling. Six steel plate shear wall specimens were tested by using a hydraulic servo actuator. The failure mode, shear resistance, lateral stiffness, and buckling mode were investigated through an experimental study. The results indicate that the width-thickness ratio of the steel plate affected the shear-carrying capacity and failure mode. A low width-thickness ratio of steel plate required adequate bonding to prevent boundary failure. The precast concrete slabs enhanced the lateral stiffness and improved the buckling strength or shear resistance of the steel plate. The material workable capability of steel plate was fully developed with a composite buckling-restraint by using the composite shear wall; similarly, the earthquake-resistant behavior of the structural system would likewise be enhanced further.
Guo Zhen,Tong Di,Zhao Yan-cheng,Chen Shuang,Nai Ji-qiu,Ye Ming-hao 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
Asynchronous motor is widely used in various industrial fields. When asynchronous motor works in case close to the rated load, it will run at maximum efficiency. However, most of the load is 50–100% of rated load and it will lead to the serious waste of energy. This paper proposes an efficiency optimization control strategy based on the grey wolf optimization algorithm to improve the operating efficiency of asynchronous motors at light loads. The motor loss model considering the change of iron loss is established and it makes the asynchronous motor model more accurate. The grey wolf optimization algorithm is used to find the optimized flux value. When the asynchronous motor operates at the optimal flux, the loss power of the motor is decreased and the operation efficiency improves effectively. The proposed method reduces the flux search time and improves the stability of the system. The simulation model is established and the simulation results are provided to verify the feasibility of the proposed control strategy achieving the global efficiency optimum of asynchronous motor.