• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.4
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• pp.351-358
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• 2003

This paper describes distribution characteristics of switching surge voltage in stator windings of induction motor driven by IGBT PWM inverter. To analyze the voltage distribution between the turns and coils of stator winding, equivalent circuit model of induction motor including cable was proposed and high frequency parameter is computed by using finite-element method (FEM). From the electro-magnetic transient program (EMTP) simulation of the whole system for induction motor, feeder cable, and PWM inverter, the variable effect on rising time of the inverter, cable length, and switching frequency on the voltage distribution is also presented. In order to experiment, an induction motor, 380[V], 50[HP], with taps from one phase are built to consider the voltage distribution so that these results can be helpful when filter was designed to remove high dv/dt.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.324-327
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• 1996

This paper presents the adoption of PWM converter to enhance input power factor in inverter arc welder. By using PWM converter in inverter arc welder, the disadvantages of bridge diode converter such as low input power factor is improved, new NCT(Noise Cut Transformer) is designed to reduce noise which has harmful effect in switching component, half bridge PWM inverter is adopted to reduce cost in inverter arc welder.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.625-629
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• 2004

This paper presents a systematical approach to study carrier based PWM techniques (CPWM) in diode-clamped and cascade multilevel inverters by using a proposed named multi-modulating pattern method. This method is based on the vector correlation between CPWM and the space vector PWM (SVPWM) and applicable to both multilevel inverter topologies. A CPWM technique can be described in a general mathematical equation, and obtain the same outputs similarly as of the corresponding SVPWM. Control of the fundamental voltage, vector redundancies and phase redundancies in multilevel inverter can be formulated separately in the CPWM equation. The deduced CPWM can obtain the full vector redundancy control, and fully utilize phase redundancy in a cascade inverter In this continued part, it will be deduced correlation between CPWM equations in multi-carrier system and single carrier system, present the mathematical model of voltage source inverter related to the common mode voltage and propose a general algorithm for multi-modulating modulator. The obtained theory will be demonstrated by simulation results.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.181-183
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• 2004

Conventional VVVF control voltage-fed inverter of blower induction motor has advantage that very speedy response characteristics for air-harmonic. But there have bad power factor on input orient have its large volume and high error ratio over 80%. And there are very expensive by reason of using the capacitor input rectifier. In this paper, It could make the smoothing capacitor-less inverter for air-blower motor by using the instantaneous compensation PWM controller. This inverter system has small volume and value compare with the conventional VVVF control inverter for blower induction motor for air-harmonic equipment.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.275-278
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• 2003

Conventional vector control inverter is usually used for blower of air-accord equipment. In this paper, it is proposed that inverter is controlled by instantaneous following PWM controller. This controller compensate and follow for output voltage of inverter within one switching cycle as an error that compared output voltage of rectifier included much ripples with reference voltage of sine wave. It has not speedy response like vector controller, but the circuit is very simple as using analog integer. And it has advantages that develop input power factor, built small-capacity and low-cost because huge capacitor of voltage type inverter removed.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.3
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• pp.366-371
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• 2012

In this paper, we propose an electric circuit using one common-arm of H-Bridge inverters to reduce the number of switching components in the multi-level inverter combined with H-Bridge inverters and transformers. And furthermore, we suggested a new multi-level PWM inverter using PWM level to reduce THD (Total Harmonic Distortion). We use a phase-shift switching method that has the same rate of usage at each transformer. Also, we test the proposed prototype 9-level inverter to clarify the proposed electric circuit and reasonableness of the control signal for the proposed multi-level PWM inverter.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1477-1479
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• 2005

In this paper, we proposed the electric circuit using one common arm of H-Bridge inverters to reduce the number of switching component in multi-level inverter combined with H-Bridge Inverters and Transformers. and furthermore we suggested the new multi-level PWM inverter using PWM level to reduce THD(Total Harmonic Distortion) and we used the switching method that can be same rate of usage at each transformer. Also, we tested the proposed prototype 15-level inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed multi-level PWM inverter.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.325-329
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• 2000

An effective Carrier-Based PWM scheme that enables the instantaneous quality of each branch point voltage of a diode clamped 4-level inverter to be reduced at a low modulation index is described. This scheme presents a computed zero sequence voltage of PWM by the feedback of both DC-link voltages and load currents. The proposed PWM scheme enables to increase the controllable region of DC-link voltage and makes it possible to operate with small DC-link capacitors. The validity of the proposed PWM scheme is verified by simulation results.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.292-294
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• 2006

This paper presents a study on the use of improved space-vector modulation of VSI employing only four switches, four body diodes. Different switching sequence strategy for vector control for inverter fault mode are described. The influence of different switching patterns at same modulation index and improved PWM method is proposed. The proposed PWM is compared with conventional PWM. Simulation and experimental results are presented.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.43-54
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• 2017

This paper analyzes the performance of two three-leg inverters and a five-leg inverter and proposes the optimal operation conditions in applying the five-leg inverter for the train propulsion system. The five-leg inverter offers a saving of two switches compared with the standard two three-leg inverters and it is possible to control two three-phase motors independently by using a control board. All of these features lead to a potential reduction in capital cost and miniaturization of system. In this paper, first, the analysis of the existing motor control method and PWM method for two-traction motor drive of urban railway is implemented. Next, the operation principle and performance of five-leg inverter is introduced. Through the analysis, when it applies the same motor control method and the same PWM method for three-leg inverter and five-leg inverter, the characteristic of motor's speed and torque is compared.