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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of the Korean Institute of Power Electronics
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Journal DOI :
The Korean Institute of Power Electronics
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Volume & Issues
Volume 20, Issue 6 - Dec 2015
Volume 20, Issue 5 - Oct 2015
Volume 20, Issue 4 - Aug 2015
Volume 20, Issue 3 - Jun 2015
Volume 20, Issue 2 - Apr 2015
Volume 20, Issue 1 - Feb 2015
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Power Line Communication-based Heated Glass Temperature Control System
Lee, Su-Hyeong ; Kim, In-Dong ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 105~114
DOI : 10.6113/TKPE.2015.20.2.105
Heated glasses are widely used to prevent surface condensation and freezing in ship and building windows. This study proposes a heated glass temperature control system composed of power and control circuits to control the temperature of heated glasses. The proposed temperature control system adopts a digital controller instead of a conventional analog controller. Thus, the proposed system has better characteristics, such as precise setup and control of glass temperature, setup and control of output power, and control mode change between ON/OFF and phase controls. The system can also implement multi-functional control algorithms. The control characteristics are not dependent upon external disturbances, such as ambient temperature and electrical noises. Furthermore, the proposed temperature control system utilizes the power line communication (PLC) method to control the number of heated glasses without any extra communication lines. The system proposes a new communication protocol with strong immunity to electrical switching noises. A new sensorless algorithm is used to detect the temperature of the heated glass. This study presents the design guidelines in detail and its effectiveness are confirmed by implementing a 4-kw prototype temperature control system.
Dead Time Compensation of Stand-alone Inverter Under Unbalanced Load
Jeong, Jinyong ; Jo, Jongmin ; Lee, Junwon ; Chae, Woo-Kyu ; Cha, Hanju ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 115~121
DOI : 10.6113/TKPE.2015.20.2.115
Stand-alone inverter supplies constant voltage to loads. However, when a three-phase stand-alone inverter supplies unbalanced load, the generated output voltages also become unbalanced. The nonlinear characteristics of inverter dead time cause a more serious distortion in the output voltage. With unbalanced load, voltage distortion caused by dead time differs from voltage distortion under balanced load. Phase voltages in the stationary reference frame include unbalanced odd harmonics and then, d-q axis voltages in the synchronous reference frame have even harmonics with different magnitude, which are mitigated by the proposed multiple resonant controller. This study analyzes the voltage distortion caused by unbalanced load and dead time, and proposes a novel dead time compensation method. The proposed control method is tested on a 10-kW stand-alone inverter system, and shows that total harmonic distortion (THD) is reduced to 1.5% from 4.3%.
Floating Voltage Stacked LED Driver for Low Voltage Stress and Multi-channel Current Balancing
Hwang, Won-Sun ; Hwang, Sang-Soo ; Kang, Jeong-Il ; Han, Sang-Kyoo ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 122~129
DOI : 10.6113/TKPE.2015.20.2.122
In this study, we propose a low voltage stress and cost-effective light emitting diode (LED) driver capable of multi-channel current balancing. Conventional LED drivers require as many boost converters as the number of LED channels, whereas the proposed LED driver requires only one buck converter and several balancing capacitors instead of several expensive boost converters. Additionally, while the components of the boost converter have high voltage stress and depend on the LED driving voltage, components of the proposed driver have about one-half of the voltage stress across all components. The proposed driver exhibits high reliability and cost effectiveness because it only uses few DC blocking capacitors with no additional active devices to balance the current of multi-channel LEDs. The proposed driver exhibits high reliability and cost effectiveness. The validity of the proposed driver is confirmed through a theoretical analysis. An explanation of the design considerations and experimental results were obtained using a prototype applicable to a 46" LED-TV.
Operation modes and Protection of VS(Vertical Stabilization) Converter for International Thermonuclear Experimental Reactor
Jo, Hyunsik ; Jo, Jongmin ; Oh, Jong-Seok ; Suh, Jae-Hak ; Cha, Hanju ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 130~136
DOI : 10.6113/TKPE.2015.20.2.130
This study describes the structure and operation modes of vertical stabilization (VS) converter for international thermonuclear experimental reactor (ITER) and proposes a protection method. ITER VS converter supplies voltage (
) to superconducting magnets for plasma current vertical stabilization. A four-quadrant operation must be achieved without zero-current discontinuous section. The operation mode of the VS converter is separated in 12-pulse mode, 6-pulse mode and circulation current mode according to the magnitude of the load current. Protection measures, such as bypass and discharge, are proposed for abnormal conditions, such as over current, over voltage, short circuit, and voltage sag. VS converter output voltage is controlled to satisfy voltage response time within 20 msec. Bypass operation is completed within 60 msec and discharge operation is performed successfully. The feasibility of the proposed control algorithm and protection measure is verified by assembling a real controller and implementing a power system including the VS converter in RTDS for a hardware-in-loop (HIL) facility.
A Study on Characteristics Analysis of Common-Mode Choke with Reduced Parasitic Capacitance
Won, Jae-Sun ; Kim, Hee-Seung ; Kim, Jong-Hae ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 137~143
DOI : 10.6113/TKPE.2015.20.2.137
This paper presents the intra capacitance modeling based on the winding method and section bobbin for CM choke capable of EMI attenuation of broad bands from lower to higher frequency bands and high frequency type common-mode choke capable of EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. The case of high frequency type CM choke can be explained by the parasitic capacitance of three types of CM choke. The winding method of section bobbin type is smaller than the others. The first resonant frequency of the proposed CM choke tends to increase as the parasitic capacitance becomes small and its impedance characteristics improved performance as the first resonant frequency increases. The CM chokes of the proposed section bobbin type shows that in the future, the method may have practical use in LED/LCD-TV SMPS and in several applications, such as LED lighting, adapters, and so on.
Analysis of the Effects According to Changes in Impedance and Electrical Equivalent Circuit Modeling of a SONAR Transducer Considering Dual Resonance
Mok, Hyung-Soo ; Choi, Jae-Hyuk ; Han, Soo-Hee ; Park, Sang-Zoon ; Kim, Sung-Joo ; Heo, Jun-Ki ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 144~151
DOI : 10.6113/TKPE.2015.20.2.144
The present study proposes a method for modeling a SONAR transducer with dual resonance. The Butterworth van-Dyke (BVD) model, a conventional SONAR transducer modeling method, can model only one resonance point. Hence, to address its disadvantage and to model the dual resonance, a dual resonance BVD model consisting of two serial BVD models is proposed. The two BVD models are connected in a series, and each simulate resonance at low frequency and high frequency, which allows the modeling of two resonance points. Eight elements compose the equivalent circuit by connecting the BVD models in a series, which is twice as great as that of the existing BVD model. The element value of the dual resonance BVD model is extracted by using the particle swarm optimization method. Analysis was also performed to identify the effects of changes in the value of elements that compose the equivalent circuit on the impedance characteristics of the equivalent circuit through simulation in which element values varied.
An Improved Grid Impedance Estimation using PQ Variations
Cho, Je-Hee ; Kim, Yong-Wook ; Kim, Rae-Young ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 152~159
DOI : 10.6113/TKPE.2015.20.2.152
In a weak grid condition, the precise grid impedance estimation is essential to guaranteeing the high performance current control and power transfer for a grid-connected inverter. This study proposes a precise estimation method for grid impedance by PQ variations by employing the variation method of reference currents. The operation principle of grid impedance estimation is fully presented, and the negative impact of the phase locked loop is analyzed. Estimation error by a synchronization angle in the park's transformation using the phase locked loop is derived. As a result, the variation method of reference currents for accurate estimation is introduced. The validation of the proposed method is verified through several simulation results and experiments based on a 2-kW voltage source inverter prototype.
A Novel Cell Balancing Circuit for Fast Charge Equalization
Park, Dong-Jin ; Choi, See-Young ; Kim, Yong-Wook ; Kim, Rae-Young ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 160~166
DOI : 10.6113/TKPE.2015.20.2.160
This study proposes an improved cell balancing circuit for fast equalization among lithium-ion (Li-ion) batteries. A simple voltage sensorless charge balancing circuit has been proposed in the past. This cell balancing circuit automatically transfers energy from high-to low-voltage battery cells. However, the circuit requires a switch with low on-resistance because the balancing speed is limited by the on-resistance of the switch. Balancing speed decreases as the voltage difference among the battery cells decrease. In this study, the balancing speed of the cell balancing circuit is enhanced by using the auxiliary circuit, which boosts the balancing current. The charging current is determined by the nominal battery cell voltage and thus, the balancing speed is almost constant despite the very small voltage differences among the batteries. Simulation results are provided to verify the validity of the proposed cell balancing circuit.
An Analysis of ZVS Phase-Shift Full-Bridge Converter's Small Signal Model according to Digital Sampling Method
Kim, Jeong-Woo ; Cho, Younghoon ; Choe, Gyu-Ha ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 167~174
DOI : 10.6113/TKPE.2015.20.2.167
This study describes how digital time delay deteriorates control performance in zero voltage switching (ZVS) phase-shifted full bridge (PSFB) converter. The small-signal model of the ZVS PSFB converter is derived from the buck-converter small-signal model. Digital time delay effects have been considered according to the digital sampling methods. The analysis verifies that digital time delays reduce the stability margin of the converter, and the double sampling technique exhibits better performance than the single sampling technique. Both simulation and experimental results based on 250 W ZVS PSFB confirm the validity of the analyses performed in the study.
The State of Charge Estimation for Lithium-Polymer Battery using a PI Observer
Lee, Junwon ; Jo, Jongmin ; Kim, Sungsoo ; Cha, Hanju ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 175~181
DOI : 10.6113/TKPE.2015.20.2.175
In this study, a lithium polymer battery (LiPB) is simply expressed by a primary RC equivalent model. The PI state observer is designed in Matlab/Simulink. The non-linear relationship with the OCV-SOC is represented to be linearized with 0.1 pu intervals by using battery parameters obtained by constant-current pulse discharge. A state equation is configured based on battery parameters. The state equation, which applied Peukert's law, can estimate SOC more accurately. SOC estimation capability was analyzed by utilizing reduced Federal Test Procedure (FTP-72) current profile and using a bi-directional DC-DC converter at temperature (
). The PI state observer, which is designed in this study, indicated a SOC estimation error rate of
in any of the initial SOC states. The PI state observer confirms a strong SOC estimation performance despite disturbances, such as modeling errors and noise.
Robust and Unity Input Power Factor Control Scheme for Electric Vehicle Battery Charger
Nguyen, Cong-Long ; Lee, Hong-Hee ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 182~192
DOI : 10.6113/TKPE.2015.20.2.182
This study develops a digital control scheme with power factor correction for a front-end converter in an electric vehicle battery charger. The front-end converter acts as the boost-type switching-mode rectifier. The converter assumes the two roles of the battery charger, which include power factor control and robust charging performance. The proposed control scheme consists of a charging control algorithm and a grid current control algorithm. The scheme aims to obtain unity input power factor and robust performance. Based on the linear average model of the converter, a constant-current constant-voltage charging control algorithm that passes through only one proportional-integral controller and a current feed-forward path is proposed. In the current control algorithm, we utilized a second band pass filter, a single-phase phase-locked loop technique, and a duty-ratio feed-forward term to control the grid current to be in phase with the grid voltage and achieve pure sinusoidal waveform. Simulations and experiments were conducted to verify the effectiveness of the proposed control scheme, both simulations and experiments.
Research of PWM Modulation for Regeneration Braking of BLDC Motor
Kim, Yong-Hyu ; Park, Sung-Jun ; Jung, Jun-Hyung ; Kim, Dong-Youn ; Kim, Jang-Mok ;
The Transactions of the Korean Institute of Power Electronics, volume 20, issue 2, 2015, Pages 193~199
DOI : 10.6113/TKPE.2015.20.2.193
This paper proposes a regeneration braking algorithm for Brushless DC (BLDC) motor system. The unipolar switching method has a limitation about the regeneration braking when the BLDC motor is operated in the low speed region. The proposed algorithm alternatively utilizes the unipolar and bipolar switching method to implement the regeneration braking for overall speed range. The bipolar switching method is used when the BLDC motor is operated in the low speed region. The switching transition point is determined by analyzing the unipolar and bipolar switching during the regeneration braking. The effectiveness of proposed algorithm is verified by using the experimental results.