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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.
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.
MARS를 이용한 속도검출기가 없는 유도전동기의 벡터제어에 관한 연구
임태윤,황돈하,김동희,김민회 영남대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.28 No.1
This paper describes a speed sensorless algorithm for vector control system with compensated rotor time constant variation of induction motor using a model reference adaptive system (MRAS). The proposed system is composed of two MRAS, one is a rotor speed estimation identification by a back-EMF observer, another is a rotor time constant identification by magnetizing current observer. As a result, robust field oriented control system of induction machine against paremeter variation can be realized. The suggested control strategy and estimation method have been validated by simulation study. In the simulation using Matlab/Simulink, the proposed speed sensorless vector control system operated very well in spite of variable rotor time constant and load fluctuation.
김동희,정경채,김민희,황돈하,이달해 嶺南大學校 工業技術硏究所 1994 工業技術硏究所論文集 Vol.22 No.1
Recently, the vector controlled induction motors are widely used in the industrial AC servo system requiring high accuracy and fast response. However, in the conventional vector control, by using of speed sensors for speed information of the motor, the system design has been restricted. This paper proposes te vector control system based on speed estimation controls motor speed by estimating angular speed of secondary flux linkages from voltage equations of induction motor without speed and voltage sensor. To stabilize the control system for estimation, the ??-axis flux keeps to zero by the compensation control method with state feedback. In addition, the whole control system is designed to be controlled by software in microcomputer. Computer simulations domonstrates that the control characteristics of the proposed vector control system based on speed estimation are satisfactory in both dynamic performance and accuracy.
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.
Robust Diagnosis Algorithm for Identifying Broken Rotor Bar Faults in Induction Motors
Don-Ha Hwang,Young-Woo Youn,Jong-Ho Sun,Yong-Hwa Kim 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.1
This paper proposes a new diagnosis algorithm to detect broken rotor bars (BRBs) faults in induction motors. The proposed algorithm is composed of a frequency signal dimension order (FSDO) estimator and a fault decision module. The FSDO estimator finds a number of fault-related frequencies in the stator current signature. In the fault decision module, the fault diagnostic index from the FSDO estimator is used depending on the load conditions of the induction motors. Experimental results obtained in a 75 kW three-phase squirrel-cage induction motor show that the proposed diagnosis algorithm is capable of detecting BRB faults with an accuracy that is superior to a zoom multiple signal classification (ZMUSIC) and a zoom estimation of signal parameters via rotational invariance techniques (ZESPRIT).
Robust Diagnosis Algorithm for Identifying Broken Rotor Bar Faults in Induction Motors
Hwang, Don-Ha,Youn, Young-Woo,Sun, Jong-Ho,Kim, Yong-Hwa The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.1
This paper proposes a new diagnosis algorithm to detect broken rotor bars (BRBs) faults in induction motors. The proposed algorithm is composed of a frequency signal dimension order (FSDO) estimator and a fault decision module. The FSDO estimator finds a number of fault-related frequencies in the stator current signature. In the fault decision module, the fault diagnostic index from the FSDO estimator is used depending on the load conditions of the induction motors. Experimental results obtained in a 75 kW three-phase squirrel-cage induction motor show that the proposed diagnosis algorithm is capable of detecting BRB faults with an accuracy that is superior to a zoom multiple signal classification (ZMUSIC) and a zoom estimation of signal parameters via rotational invariance techniques (ZESPRIT).
Support Vector Machine Based Bearing Fault Diagnosis for Induction Motors Using Vibration Signals
Don-Ha Hwang,Young-Woo Youn,Jong-Ho Sun,Kyeong-Ho Choi,Jong-Ho Lee,Yong-Hwa Kim 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.