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電壓形 PWM Inverter에 依한 誘導電動機의 精密 速度制御
金玟會,鄭瓊採,金東熙,李達海,黃敦夏 嶺南大學校 工業技術硏究所 1992 연구보고 Vol.20 No.1
For precision control of Induction Motor with Voltage Source PWM Inverter, the current component should be converted into the voltage one. We are in difficulties for precision control with simple current feedback control because of the oscillation in system and torque ripple on high speed rotation and transient switching resulted from the disturbance which is generated by the mutual interference between d-axis and q-axis during conversion. This paper propose linearized Decoupling Control Theory in Field-Oriented Control and presents controllable system with Microcomputer software in the whole control system. In addition, by experiment it is proved that the system is controlled well in both steady and transient states. The proposed system is expected to be applied in industrial AC Servo System.
고속전철 추진 시스템의 미끄럼 방지 제어기법에 관한 연구
황돈하,김동희,노채균,심광열,조규판,정원영 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2
Induction motor drive with PWM inverter control has been developed for Korean High Speed Railways. To improve traction performance, the anti-slip control(ASC) to recover adhesion must be considered. This paper describes a novel hybrid anti-slip control method for the induction motor drive. By introducing the vector control for drive system, quick response of the motor torque can be achieved when wheels are going to slip. A hybrid control scheme by mixing two conventional control methods (slip velocity feedback control and slip detection pattern control) for wheel slip and re-adhesion is proposed. This control method is simulated by motor drive, train load, and friction-creep models. The train running simulation results based on induction motor vector control with PWM inverter show that good re-adhesion characteristics are obtained.
황돈하,김동희,이광식,정원영,김영훈,오승훈 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2
Inverters with high speed switching and advanced PWM techniques are widely used for variable speed applications. But some adverse effects on the stator winding insulation are reported due to excessive voltage stress, which results in the premature insulation breakdown. This is aggravated by the high switching speed of modem switching devices such as IGBT (Insulated Gate Bi-polar Transistor) with which the rate of rise in voltage (dv/dt) increases considerably. In this paper, the test results for evaluation on the stator winding insulation of 310V induction motors are presented. Also, the insulation characteristics are presented in order to analyze the insulation strength under high voltage due to high switching speed of IGBT PWM inverter. 26 induction motors of 6 types with different wires and insulation techniques are built and thoroughly tested. The maximum partial discharge (PD) magnitude (Qm) and the discharge inception voltage (DIV) are obtained by PD test. Under AC current test, the rate of change in AC current (ΔI) and the change in dissipation factor (Δtanδ) are measured. From the above test data, the effects due to different wires and insulation techniques on the insulation characteristics of low-voltage induction motors are compared and analyzed. The insulation technique to enhance the insulation strength is suggested from the test results.
급속응고된 Fe-6.5wt% Si 강판의 미세조직과 자기적 특성에 미치는 열처리의 영향
황돈하,이갑호,이태행,구자명 ( D . H . Hwang,K . H . Lee,T . H . Lee,J . M . Koo ) 한국열처리공학회 1995 熱處理工學會誌 Vol.8 No.2
The alloying of 6.5wt% Silicon in iron decreases the magnetization and the anisotropy and minimizes the iron loss noticeably. But it is very difficult to make thin sheets because of its poor ductility which is due to an ordering reaction (body centered cubic to CsCl type crystal structure). However the ordering reaction can be suppressed by rapid solidification method. The cooling rate of rapidly solidified Fe-6.5wt% Si alloy is about 10³K/s and rapidly solidified structure are fine structure, cellular structure, dendrite and equiaxed grain from surface. The precipitates of DO₃Phase emerges on B₂matrix and the coercive force was 0.51 Oe (50cycle, 15KGauss) in Fe-6.5wt% Si alloy which was processed by heat treatment of 1150℃ for 1hr in high vacuum.
인버터 구동 유도전동기 고정자 권선의 함침기법에 따른 절연성능 평가
황돈하,강동식,김용주,이인우,구자윤,김동희,이광식 대한전기학회 2006 전기학회논문지C Vol.55 No.7(C)
- The low-voltage induction motors have been widely driven by IGBT PWM inverters, ever since it was used to apply variable speed drives. Recently, the insulation failures of the stator windings become critical problems due to the high ratio of dv/dt in IGBT PWM inverters. In this paper, the detailed insulation tests on the IGBT PWM inverter fed induction motor are carried out. Five different types of insulation techniques are used to 25 induction motors. The change of the insulation characteristics such as partial discharge, AC current, capacitance, and dissipation factor are compared, respectively. In addition, insulation breakdown tests using the high voltage pulse are performed, and corresponding breakdown voltages are analyzed.
Support Vector Machine Based Bearing Fault Diagnosis for Induction Motors Using Vibration Signals
황돈하,윤영우,선종오,최경호,이종호,김용화 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4
In this paper, we propose a new method for detecting bearing faults using vibration signals. The proposed method is based on support vector machines (SVMs), which treat the harmonics of fault-related frequencies from vibration signals as fault indices. Using SVMs, the cross-validations are used for a training process, and a two-stage classification process is used for detecting bearing faults and their status. The proposed approach is applied to outer-race bearing fault detection in threephase squirrel-cage induction motors. The experimental results show that the proposed method can effectively identify the bearing faults and their status, hence improving the accuracy of fault diagnosis.
고분해능 전자현미경에 의한 Al-Li-Cu-Mg-Ag-Zr합금의 석출거동에 관한 연구
황돈하 충남대학교 대학원 1994 論文集 Vol.14 No.-
The precipitation behavior in A12.28wt%Li1.11wt%Cu0.57wt%Mg0.18wt%Zr(8090)and AI1.3wt%Li5.4wt%Cu0.4wt%Mg0.4wt%Ag0.17wt%Zr(welda lite 049) alloys have been studied by using a high resolution electron microscope. Weldalite 049 alloy has a higher micro vichers hardness values than that of 8080 alloy. In the alloys quenched from 530℃, the LI_2-type microdomains and regions having lattice modulation parallel to {100} planes are abserved in an atomic resolution image and G.P zone is observed in Weldalite 049 alloy. In the δ'/θ' complex precipitates, interface boundary on both faces of θ' plate is atomically flat and coherent with surrounding δ' phase and an antiphase relation is formed between the δ' phases on both faces of θ' plate. Nucleation sites of S'phase are observed at not only δ' /matrix interface and subgrain boundary, but Cu and Mg clusters.