• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.645-648
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• 1991

In conventional sinusoidal wave PWM control, torque oscillation is a problem on account of harmonic component. This paper deals with the choice of line-to-line voltage modulation method, which is effective in using DC(direct current) source voltage and in controlling harmonic oscillation, and the pattern to reduce swiching loss through 1/3 pause of switching interral. So, this paper deals with valid realization of harmonic component and high torque response on variable load by simulation and experiments to compensate occurring problems when line-to-line modulation are applied to PWM inverter.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.201-202
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• 2012

This paper presents design and implementation of the PCU(150 kVA 3-Phase PWM Inverter for Electric Vehicles). For Implementation of the PCU, it is consist with Case, Connectors, IGBT module for PWM switching, DC-capacitor for dc-source, resolver for sensing of speed & position, and PCB board for control & gate-driver. Also, for the purpose of stable operation of the PCU in vehicle with variable torque condition in motor, current control scheme based on torque-map are developed. According to real-car test mode, the prototype of proposed the PCU is verified with performance and stability. Thus, design and implement of the PCU are discussed, and experimental results are presented in this paper.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.52-54
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• 2002

A resonant type voltage source and power device and a control method using Pulse Density Modulation(PDM) power control and Pulse Width Modulation(PWM) voltage control for plasma sterilization are described, For the stability of discharge in the generating tube, it is desirable that the peak apply voltage is constant. The PDM power control is employed for sustaining the voltage constant at any generating tube input power. Moreover, to avoid the influence of input AC voltage fluctuation etc.. PWM voltage control with generating tube peak voltage feedback is used. Both functions were confirmed by the experiment with 6.5[kHz], 1.8[kW] inverter and generating tube. The effect of input synchronous PDM method for input current stabilizing is confirmed also.

• Journal of Power Electronics
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• v.5 no.3
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• pp.233-239
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• 2005

In this paper, a new conceptual circuit configuration of a 3-phase voltage source, soft switching AC-DC-AC converter using an IGBT module, which has one ARCPL circuit and one ARDCL circuit, is presented. In actuality, the ARCPL circuit is applied in the 3-phase voltage source rectifier side, and the ARDCL circuit is in the inverter side. And more, each power semiconductor device has a novel clamp snubber circuit, which can save the power semiconductor device from voltage and current across each power device. The proposed soft switching circuits have only two active power semiconductor devices. These ARCPL and ARDCL circuits consist of fewer parts than the conventional soft switching circuit. Furthermore, the proposed 3-phase voltage source soft switching AC-DC-AC power conversion system needs no additional sensor for complete soft switching as compared with the conventional 3-phase voltage source AC-DC-AC power conversion system. In addition to this, these soft switching circuits operate only once in one sampling term. Therefore, the power conversion efficiency of the proposed AC-DC-AC converter system will get higher than a conventional soft switching converter system because of the reduced ARCPL and ARDCL circuit losses. The operation timing and terms for ARDCL and ARCPL circuits are calculated and controlled by the smoothing DC capacitor voltage and the output AC current. Using this control, the loss of the soft switching circuits are reduced owing to reduced resonant inductor current in ARCPL and ARDCL circuits as compared with the conventional controlled soft switching power conversion system. The operating performances of proposed soft switching AC-DC-AC converter treated here are evaluated on the basis of experimental results in a 50kVA setup in this paper. As a result of experiment on the 50kVA system, it was confirmed that the proposed circuit could reduce conduction noise below 10 MHz and improve the conversion efficiency from 88. 5% to 90.5%, when compared with the hard switching circuit.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1020-1022
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• 2001

because the output of solar cell is direct, it is necessary to install D/A converter system for A.C load, and in case of driving utility line system, it is possible to drive system relation when the system supplies sinusodal current ant voltage having unit power factor. As the characteristics of the soar cell output the is influenced by dailysunight charge, for more electric power it is essential to control the direction toward the san so that the driving point of solar cell can always operate near maximum output point. PWM modulation device among electric power converters must have stable modulation at anytime when it includes noise-factors such as noise-wave and noises on electric voltage wave, a synchronous signal system. In dealing with synchronous signal for control and control signal by microprocessor, it is necessary to compensate it because there is time difference between sample paint and carrier wave. On this papers, single phase PWM current type invertor controled the solar cell having typical voltage dropping character has optimun short current in short, reduces D.C reactance, composes controller for modulation and keeps lower harmonic and high power factor keeping maximum output of solar cell according daily sunlight charge variation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.211-218
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• 2000

The performance and dynamic characteristics of three-phase active power filter with PCC voltage compensation is presented and analyzed in this paper. The characteristics of parallel active filter are discussed when they are applied to nonlinear loads with current source and voltage source type, the characteristics of voltage compensator and comparison of two functions are discussed. The proposed scheme in this paper employs a PWM voltage-source inverter and has two operation modes. First, it operates as a conventional active filter with reactive power compensation while PCC voltage is in a certain range. Second, is operates as a voltage compensator while PCC voltage is out of range. Finally, the validity of this scheme is investigated through analysis of simulation and experimental results for a prototype active power filter system rated at 10KVA.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.399-402
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• 2006

This paper presents a new circuit topology of dc bus line switch-assisted half-bridge soft switching PWM inverter type dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to dc bus line side power semiconductor switching devices fer PWM control scheme and capacitive lossless snubbers. All the active power switches in the half-bridge arm and dc bus lines can achieve ZCS turn-on and ZVS turn-off commutation operation and consequently the total turn-off switching losses can be significantly reduced. As a result, a high switching frequency of using IGBTs can be actually selected more than about 20 kHz. The effectiveness of this new converter topology is proved for low voltage and large current dc-dc power supplies such as arc welder from a practical point of view.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.1
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• pp.53-60
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• 2013

In this paper, a control algorithm for active power filter (APF), which compensates for the harmonics and power factor, boosting the DC-link voltage is proposed. The proposed scheme employs a pulse-width-modulation (PWM) voltage-source inverter. A simple algorithm to detect the load current harmonics is also proposed. The APF and charging circuit are implemented in one inverter system. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype APF system rated at 3kVA.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.417-424
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• 2007

This paper presents a solution that an analytical model for an induction motor and the formula of regenerative power and instantaneous torque are derived. based on the spiral vector. The torque is controlled linearly through variations of the slip angular velocity, based on the field acceleration method (FAM). And also PWM inverter fed induction motor drives is schemed to be easily a regenerative drive. The voltage source inverter fed induction motor drives that regenerative power occurs with back current type is presented, to easily controlled the feedback power and to proper the adaption of energy shaving drives. The experimental tests verify the performance of the FAM, proving that food behavior of the drive is achieved in the transient and steady state operating condition, and are discussed to save the power that regenerative power is measured at the operating acceleration or deceleration of servo system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.1
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• pp.23-33
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• 2002

A hysteresis control is widely used to control output current of inverter. A hysteresis bandwidth is affected by system parameters such as source voltage, device on/off time, load inductance and resistance. The frequency limiter is used to protect switching devices overload. In the conventional hysteresis controller, a lock-out circuit with D-latch and timer is used to device protection circuit. But switching delay time and harmonic components are appeared in output current. In this paper the performance of lock-out circuit is tested, and new circuit for switching device fault protection is proposed ad it's performance is simulated.