• KIEE International Transactions on Power Engineering
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• 제5A권1호
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• pp.22-30
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• 2005

The PWM inverter drive may cause an over voltage at the motor terminal, which imposes severe electric stresses on the inter-turn insulation of motor windings. Unlike low-voltage induction motors, high-voltage induction motors have a stator type of form-wound coil for insulation and are insulated to the slot and the coil. So, this paper presents a PWM 3-level inverter, H-Bridge cascaded 7-level inverter and High-voltage induction motor model. It then analyzes the voltage that generates at the input terminal of the high-voltage induction motor fed by each inverter. Also, in order to examine a factor that influences the switching surge voltage, this paper proposes the system equivalent model and performs the case studies using EMTP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1131-1132
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• 2011

For the purpose to flow control of pump in booster pump station, nonlinear-load inverter equipment is being introduced. While inverter equipment has the advantage of power-ratio savings and volume control, due to the vibration of pump and motor, secondary breakdown may occur Purpose in this paper is reliable facility operation by providing optimal operationg standards through vibration analysis of apply to drive pump with inverter in long-term in booster pump station.

• 전기학회논문지
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• 제56권4호
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• pp.683-692
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• 2007

An inverter driven induction motor has more superior dynamic characteristic than sine wave driven induction motor. But it has a problem with shaft voltage and bearing current in drive-motor system. This paper presents the analysis of bearing current in inverter-fed induction motor. The proposed method is based on using numerical method (FEM) to derive parasitic parameters in motor. Using the electric field analysis with FEM, the stored energy in dielectric materials of the motor can be calculated and the parasitic capacitances are obtained. Then we compared the proposed method with a conventional method in variable frequency and load conditions. From the comparision of simulation and experiment result, we confirmed that the proposed method is valid.

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.80-84
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• 2006

The sustained oscillation of rotor speed is often experienced in PWM inverter induction motor (IM) drive systems. In this paper the oscillation is investigated from the point of view of Hopf bifurcation theory. The sufficient and necessary conditions for existence of limit cycle are introduced to determine the bifurcation set in the stator voltage versus stator frequency plane. According to the conditions it is clarified that the bifurcation set inherently exists in the instable operation of IM. Moreover, it is numerically shown that the V/f curve can be adjusted to stabilize the sustained oscillation of rotor speed.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.48-58
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• 2011

In this paper, an attempt has been made to design the current and speed proportional and integral (PI) regulators of self-commutating current source inverter-fed induction motor drive having capacitors at the machine end and to investigate the transient performance of the same for step changes in reference speed. The mathematical model of the complete drive system is developed in closed loop, and the characteristic equations of the systems are derived using perturbation about steady-state operating point in order to develop the characteristic equations. The D-partition technique is used for finding the stable region in the parametric plane. Frequency scanning technique is used to confirm the stability region. Final selection of the regulator parameters is done by comparing the transient response of the current and speed loops for step variations in reference. The performance of the drive is observed analytically through MATLAB simulation.

• Journal of Power Electronics
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• 제9권5호
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• pp.679-690
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• 2009

The paper presents a new photovoltaic inverter for stand-alone induction motor application. The proposed system is composed of two stages. First stage is for the photovoltaic dc power feeding and second stage is dedicated to the motor-inverter subsystem and control technique. A direct torque control (DTC) with a novel switching strategy for motor torque ripple minimization is introduced. The novel DTC strategy is based on selecting a suitable voltage vector group for motor torque ripple minimization. A three-level voltage source inverter (VSI) is used instead of a two level inverter because the first has more available vectors and lower ripples in the output current and flux than the second, thus it has lower torque ripples. The photovoltaic array and battery bank are sized and the configuration is indicated based on sun-hour methodology. Simulation results show a comparison between three systems; two level VSI with conventional DTC strategy, three level VSI with conventional DTC, and the proposed system that has a novel DTC switching strategy applied to three level VSI. The results show that the proposed system has lower ripples in the current, flux and torque of the motor.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1337-1344
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• 2013

This paper presents a simplified modulation strategy for the three-leg VSI fed two-winding induction motor. The strategy provides independent unbalanced voltage control for the main and auxiliary windings. This make the motor can be reversed rotation through the range of motor speed operation without limitation of voltage boost of the auxiliary winding. To study the advantages of the proposed drive, the experimental results such as voltage stresses, hysteresis band of the currents in locus, and also acoustic noise levels of the three-leg VSI are compared with those of the conventional two-leg topology. The results obviously show that the proposed technique achieves superior performance compared with the traditional scheme in case of dramatic increase of DC bus utilization, effective reduction of harmonic voltages content, and also significant enhancement of motor efficiency.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.458-465
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• 1998

This paper presents an inverter-driven induction motor used as the traction motor for a high speed drive system that is required safety, reliability and performance and so on, In the respect of traction motor design, it is mainly showed the weight reduction inclination and characteristic investigation due to V/f driving pattern variation of inverter. Particularly, the reduction of V/f ratio pattern effects on the weight of traction motor and badly on the increase of phase current of traction motor in starting point. This method of weight reduction design have to be reached the decision with not only motor but also the consideration of inverter system because of the heat capacity, weight and material cost of inverter according to the increase of current.

• Journal of Power Electronics
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• 제6권4호
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• pp.279-289
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• 2006

This paper presents a neural network based adaptive dead-time compensation strategy for an inverter fed permanent magnet synchronous motor drive. The neural network is used for identifying the dead-time compensation time (DTCT) that includes an equivalent dead-time, turn-on/off time and on-state voltage components of the voltage source inverter. In order to train the neural network, desired DTCTs for eight operating points are prepared as training data. The trained neural network can identify a desired DTCT for any operating point because it has the capability of the interpolation. The accuracy of the identified DTCT is experimentally confirmed by comparing the calculated active power with a measured one.

• 전력전자학회논문지
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• 제4권6호
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• pp.579-588
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• 1999

이 논문은 PWM 인버터-유도전동기 구동 시스템에서 발생되는 전도노이즈를 예측하기 위한 기법을 제시하였다. 전도노이즈 예측을 위한 시뮬레이션 모델을 얻기위하여 기생성분을 갖는 인버터에 대한 고주파수 모델과 고정자권선의 복수코일모델을 설계하였다. 마지막으로 결과는 시뮬레이션과 실험으로 확인되었다.