• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.4
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• pp.285-292
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• 2009

In this paper, when ac motors are driven by the diode rectifier/Z-source inverter system, the common-mode voltages of system are analyzed in details under both the shoot-through state and non-shoot-through state through equivalent circuits. Then a modified space vector modulation strategy is suggested for attenuating the negative common-mode voltage by eliminating the zero voltage vector, and also controlling the shoot-through time. Through the simulation studies with PSIM and experiments with 32-bit DSP, it is verified that the negative common-mode voltage can be reduced by more than 50%.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.852-857
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• 2007

For electric traction using a large power converter, harmonic problem in the p-ower quality and regenerating energy in side of efficiency are important. Recently, by advance in power electronics technology, some countries are considering regenerative inverter from the points of view. when the electric tractions are stopped or driven through the falling slope way, it is very useful to supply surplus energy to the power source by regenerating system in the efficient side of energy and it is very economical. these regenerating energy are supported electrical equipment through DC line. In this research, the purposes are suppressing extra DC-line voltage and saving energy generated while electric traction is been driving on the falling slope way or reducing speed for railway using a 1500V DC-voltage. Besides, the accompanied defects of current distortion, low power factor and the voltage unbalance will be solved by developing the algorism of inverter having ability to compensate current harmonic.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.449-451
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• 1999

When the traction motor for urban transit E.M.U is driven with VVVF controlled inverter, the insulation degradation factors on the 200 Class insulation system of VPI process are analyzed with considering dielectric, mechanical properties, thermal stability, chemical resistivity and compatibility. A new test method of complex accelerating degradation is proposed to evaluate the insulation reliability and the long-term life including harmonic loss and transient surge stress due to PWM inverter drive.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.427-433
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• 2002

An inverter-driven induction motor is usually adapted to the traction motor for a high speed drive system requiring safety, reliability, performance, compact size owing to the space and weight alloted for attaching to train, etc. and AC Traction motor for G7 train will be operated in the worst condition such as mechanical vibration, limited mounting space, severe thermal stress, inverter with non-sinusoidal voltage waveform, dust and so on. therefore, design procedure must be carefully carried out wi th considering the motor size, vibration and thermal expansion of rotor bars, insulation system, reliability of frame, as well as output characteristics. In this paper, we will inform the characteristics and design of the traction motor for G7 train and also analyze the test result of it.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.420-428
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• 2018

In this paper, represented uninterruptible power supply (UPS) equipment maintaining constant output voltage, the proposes a photovoltaic system constructed with a step up boosting chopper and single phase pulse width modulation (PWM) voltage source inverter. as power source disconnection, voltage variation and output current variation with load variation. This system is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to DC side with solar cell using a Photovoltaic that it was so called constant voltage charge. It can be results of saving electric power, and through a normal operation of energy storage system (ESS), the system operated the LED a calling on signal changes at the airport in an efficient manner. In addition, better output waveform was generated because of PWM method, and it was proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.369-371
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• 1999

A torque ripple minimization technique is proposed for high power induction motors driven by 3-level inverters with switching frequency of inverter switching elements limited around 500Hz level. It is noted that conventional DTC algorithms with torque ripple minimization scheme are devised for applications with relatively high switching frequency above 2-3kHz. A new DTC algorithm, especially for low switching frequency inverter system, illustrates relatively reduced torque ripple characteristics all over the operating speed region. Simulation results show effectiveness of the proposed control algorithm, and associated experimental works will be presented in the final paper.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.341-344
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• 1997

This paper presents a dynamics failure detection algorithm developed for the two-motor-driven electric vehicle system. The algorithm is based on the application of the fault detection filter. The fault detection includes the identification of sudden pressure drops of the two rear tires in driving axis and dynamics faults of the two inverter-motor-paired actuators An E.V. dynamics simulator is developed, which includes the modeling of the E.V. dynamics as well as the driving dynamics. The simulator, which allows the generation of various fault situations, is utilized in the verification of the developed fault detection algorithm. The results of the simulations are also presented.

• Journal of Power Electronics
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• v.12 no.3
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• pp.387-398
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• 2012

It is known that transformer based power supplies for ozone generators have low efficiency, high cost and exhibits a limited frequency range of operation. To overcome these disadvantages, this paper proposes a high frequency ozone generator with the absence of a transformer. The voltage step-up is achieved only by utilizing the resonant tank. This is made possible by a novel combination of ozone chamber materials that allow ozone to be generated at only 1.5 - 3.5 $kV_{p-p}$. The input to the resonant tank is driven by a PWM full bridge resonant inverter. Furthermore, zero-current zero-voltage switching (ZCZVS) operation is achieved by employing a duty factor of 25% between the switches of the full bridge. The advantages of the proposed system include high efficiency, low cost and the ability to control ozone production by varying the input voltage to the inverter. The prototype is verified by both simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1872-1882
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• 2017

Medium voltage drive systems driven by high-power multi-level inverters operating at low switching frequency can reduce the switching losses of the power device and increase the output power. Employing subsection synchronous current harmonic minimum pulse width modulation (CHMPWM) technique can maintain the total harmonic distortion of current at a very low level. It can also reduce the losses of the system, improve the system control performance and increase the efficiency of DC-link voltage accordingly. This paper proposes a subsection synchronous CHMPWM approach of active neutral point clamped five-level (ANPC-5L) inverter under low switching frequency operation. The subsection synchronous scheme is obtained by theoretical calculation based on the allowed maximum switching frequency. The genetic algorithm (GA) is adopted to get the high-precision initial values. So the expected switching angles can be achieved with the help of sequential quadratic programming (SQP) algorithm. The selection principle of multiple sets of the switching angles is also presented. Finally, the validity of the theoretical analysis and the superiority of the CHMPWM are verified through both the simulation results and experimental results.

• Proceedings of the KIEE Conference
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• summer
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• pp.1193-1195
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• 2004

Ozone gas is one of the strongest oxidizing and bleaching agents which leave no residues harmful to the global environment. In recent years, the ozone generator has been widely utilized, However, it has been known that a broader application of ozone is hindered primarily because of its low efficiency of generation. Thus, it is more indispensable to improve actual system efficiency of the silent discharge type ozonizer using high frequency inverter. This paper presents a multi level resonant ozone power regulation by association of high frequency transformers and full bridge invert. And proposed resonant inverter system can generate continuous output voltage. can control linearly quantity of ozone gas. This invert that add PWM forms within square forms of output voltage about one level range. The power regulation characteristics and operating performances of silent discharge (SD)type ozone generating tube load driven by this load proposed inverter using FET modules are illustrated from a practical point of view, which can operate under stable conditions of basic level and PWM hybrid control strategy implemented DSP(2406). The effectoveness of propsed invert type ozonizer is proved by experiment results.