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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 19, Issue 6 - Dec 2014
Volume 19, Issue 5 - Oct 2014
Volume 19, Issue 4 - Aug 2014
Volume 19, Issue 3 - Jun 2014
Volume 19, Issue 2 - Apr 2014
Volume 19, Issue 1 - Feb 2014
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Reliability Improvement of H-Bridge Multi-level Inverter for Medium-Voltage & High-Power Induction Motor Drives
Park, Young-Min ; Lee, Kwang-Hwan ; Lee, Se-Hyun ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 99~105
DOI : 10.6113/TKPE.2014.19.2.99
This paper proposes the reliability improvement of H-Bridge Multi-level (HBM) inverter. This reliability can be implemented through modularization of power circuit, distribution of controller, duplication of controller and communication, and continuous operation method in case of power cell failure for driving medium-voltage & high-power induction motor. It is shown that the modularization and expansion characteristics of the HBM inverter are improved since the individual inverter modules operate more independently when using the proposed concept. Also the fault tolerance is increased by using power cell bypass. The proposed design and control methods are described in detail and the validity of the proposed system is verified experimentally in various industrial fields.
Design and Test of ESS DC-DC Converter using Zinc-Bromine Redox Flow Battery for Stand-alone Microgrid
Choe, Jung-Muk ; Ra, Sun-Gil ; Han, Dong-Hwa ; Lee, Yong-Jin ; Choe, Gyu-Ha ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 106~115
DOI : 10.6113/TKPE.2014.19.2.106
This paper proposes ESS DC-DC Converter using Redox Flow Battery (RFB) for stand-alone microgrid. Price, safety, expandability and dynamics are crucial in ESS. Reports show that Zinc-bromine (ZnBr) RFB is the best choice in ESS. Simple electrical ZnBr RFB model is obtained from charging test. DC-DC converter Inductor current-DClink Voltage model is proposed for the DC microgrid. For the controller design in z-domain, the K-factor method is by considering nature of the digital controller. The control performance has been verified with simulation and hardware experiments. Lastly 10kW DC microgrid using RFB test result is shown.
A New High Efficiency Interleaved Buck Converter with Soft-switching Scheme
Kim, Nak-Yoon ; Choi, Hyun-Chil ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 116~123
DOI : 10.6113/TKPE.2014.19.2.116
In this paper, a soft-switching scheme for the PWM interleaved buck converter(IBC) is newly proposed to obtain the advantages of both the conventional PWM interleaved buck and resonant converters such as ease of control, reduced switching losses and stresses, and low EMI. To obtain the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional interleaved buck converter and used to achieve soft-switching for both the main switches and the output diodes while not incurring any additional losses due to the auxiliary circuit itself. In this paper, the basic operations are discussed and design guidelines are presented. And through the experimental results, the usefulness of the proposed converter is verified.
Implementation of Non-time-varying Duty Ratio Transfer Function for Improvement of Control Characteristics Bi-directional Charger
Hwang, Jung-Goo ; Kim, Sun-Pil ; Han, Sang-Taek ; Kim, Ki-Seon ; Choo, Young-Bae ; Park, Sung-Jun ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 124~132
DOI : 10.6113/TKPE.2014.19.2.124
In this paper, we implement a non-time-varying transfer function of the duty ratio to improve the control characteristics in a control system that Input voltage and the output voltage is varied, DC / DC converters for bi-directional charging. When control is performed with using controller gain of conventional design, characteristics of the control is varied to fluctuations of the input voltage. The proposed method is the equivalently removing method for duty ratio in entire control block, by voltage controller gain is changed for inverse of the duty ratio. The proposed non-time-varying duty ratio transfer function is applied to DC / DC converter for bi-directional charging. In this paper, feasibility and superiority is verified through PSIM simulations and experiments.
The Analog-circuited Low-loss Bypass Current Sensing Method for Average Current Mode Control
Kim, Seok-Hee ; Choi, Byung-Min ; Park, Joung-Hu ; Jeon, Hee-Jong ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 133~138
DOI : 10.6113/TKPE.2014.19.2.133
This paper proposes a low power-loss averaging current mode control using a resistor and bypass switch. Generally, current sensing method using a resistor has a disadvantage of power loss which degrades the efficiency of the entire systems. On the other hand, proposed measurement technique operating with bypass-switch connected in parallel with sensing resistor can reduce power loss significantly the current sensor. An analog-circuited bypass driver is implemented and used along with an average-circuit mode controller. The bypass switch bypasses the sensing current with a small amount of power loss. In this paper, a 50[W] prototype average current mode boost converter has been implemented for the experimental verification.
Novel Estimation Technique for the State-of-Charge of the Lead-Acid Battery by using EKF Considering Diffusion and Hysteresis Phenomenon
Duong, Van-Huan ; Tran, Ngoc-Tham ; Park, Yong-Jin ; Choi, Woojin ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 139~148
DOI : 10.6113/TKPE.2014.19.2.139
State-of-charge (SOC) is one of the significant indicators to estimate the driving range of the electric vehicle and to control the alternator of the conventional engine vehicles as well. Therefore its precise estimation is crucial not only for utilizing the energy effectively but also preventing critical situations happening to the power train and lengthening the lifetime of the battery. However, lead-acid battery is time-variant, highly nonlinear, and the hysteresis phenomenon causes large errors in estimation SOC of the battery especially under the frequent discharge/charge. This paper proposes a novel estimation technique for the SOC of the Lead-Acid battery by using a well-known Extended Kalman Filter (EKF) and an electrical equivalent circuit model of the Lead-Acid battery considering diffusion and hysteresis characteristics. The diffusion is considered by the reconstruction of the open circuit voltage decay depending on the rest time and the hysteresis effect is modeled by calculating the normalized integration of the charge throughput during the partial cycle. The validity of the proposed algorithm is verified through the experiments.
Power Control of Three Phase PWM Converter for Small-scale Wind Power using Flux Weakening Control in Over Wind Speed Region
Ku, Hyun-Keun ; Kim, Jae-Heung ; Lee, Hyung-Uk ; Kim, Jang-Mok ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 149~156
DOI : 10.6113/TKPE.2014.19.2.149
This paper proposes the battery charging algorithm for small-scale wind power generator using three phase PWM converter. it is impossible to control output power of the converter in over wind speed region since back EMF of PMSG is higer than battery voltage. Therefore, battery charging algorithm is proposed to expand battery charging over wind speed region. The suggested method is using the q-axis current for battery charging in the rated wind speed region. In the over wind speed region after it lower back EMF of PMSG using d-axis current it can control output power of the converter. The validity of the proposed algorithm are verified by experiments.
Low-Cost High-Efficiency Two-Stage Cascaded Converter of Step-Down Buck and Tapped-Inductor Boost for Photovoltaic Micro-Inverters
Jang, Jong-Ho ; Shin, Jong-Hyun ; Park, Joung-Hu ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 157~163
DOI : 10.6113/TKPE.2014.19.2.157
This paper proposes a two-stage step-down buck and a tapped-inductor boost cascaded converter for high efficiency photovoltaic micro-inverter applications. The proposed inverter is a new structure to inject a rectified sinusoidal current into a low-frequency switching inverter for single-phase grid with unity power factor. To build a rectified-waveform of the output current. the converter employs both of a high efficiency step-up and a step-down converter in cascade. In step-down mode, tapped inductor(TI) boost converter stops and the buck converter operates alone. In boost mode, the TI converter operates with the halt of buck operation. The converter provides a rectified current to low frequency inverter, then the inverter converts the current into a unity power-factor sinusoidal waveform. By applying a TI, the converter can decrease the turn-on ratios of the main switch in TI boost converter even with an extreme step-up operation. The performance validation of the proposed design is confirmed by an experimental results of a 120W hardware prototype.
Analysis of Leakage Inductance for Toroidal Type Flyback Transformer
Park, Chang-Soo ; Kang, Byeong-Geuk ; Shin, Kyoung-Gu ; Chung, Se-Kyo ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 164~172
DOI : 10.6113/TKPE.2014.19.2.164
This paper presents an analysis of a leakage inductance for a toroidal type flyback transformer. The equation to calculate the leakage inductance is derived using the MMF diagram of the transformer. The analysis for the different types of the cores and winding structures is also provided using the FEM simulation. The winding structures minimizing the leakage inductance are finally discussed from the simulation and experimental results.
Comparative Analysis of Power Losses for Three-Level T-Type and NPC PWM Inverters
Alemi, Payam ; Lee, Dong-Choon ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 173~183
DOI : 10.6113/TKPE.2014.19.2.173
In this paper, an analysis of power losses for the three-level T-type and neutral-point clamped (NPC) PWM inverters is presented, in which the conduction and switching losses of semiconductor devices of the inverters are taken into account. In the inverter operation, the conduction loss depends on the modulation index (MI) and power factor (PF), whereas the switching loss depends on the switching frequency. Power losses for the T-type and NPC inverters are analyzed and calculated at the different operating points of MI, PF and the switching frequency, in which the four different models of semiconductor devices are adopted. In the case of lower MI, the NPC-type is more efficient than the T-type, and vice versa. The validity of the power loss analysis has been verified by the simulation results.
Development of the Zero-Phase-Error Speed Controller for High Performance PMSM Drives
Kim, Joohn-Sheok ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 184~193
DOI : 10.6113/TKPE.2014.19.2.184
This paper presents a high performance ZPE(zero-phase-error) speed controller for PMSM(permanent magnet synchronous motor) drives. A comparison study between conventional general purpose speed controller in modern industry fields such as PI, IP and 2-degree of freedom controller presented also. The proposed ZPE speed controller is found suitable for vector controlled PMSM drives in giving the high level of performance while maintaining the excellent response at the time of speed command changing. In MATLAB-based comparative simulation and experiment results with commercial drive system, the proposed method shows a superior control performance compared with the conventional speed controller widely-used.
A Seamless Transfer Method of Bidirectional DC-DC Converter for ESS in DC Micro-grids
Kwon, Min-Ho ; Park, Jung-Sung ; Choi, Se-Wan ;
The Transactions of the Korean Institute of Power Electronics, volume 19, issue 2, 2014, Pages 194~200
DOI : 10.6113/TKPE.2014.19.2.194
In DC micro-grid system energy storage systems (ESS) are responsible for storing energy and balancing power. Also, control target of the bidirectional DC-DC converter(BDC) for ESS should be changed depending on the operating mode. During the grid connected mode, the BDC controls the battery current or voltage. When a grid fault occurs, the BDC should change the control target to regulate the DC-bus. The BDC with conventional control method may experience large transient state during the mode change. This paper proposes a control method of BDC for ESS. The proposed control method is able to provide autonomous and seamless mode transfer by a variable current limiter. To validate the proposed concept, simulation results using PSIM and experimental results from a 2kW prototype are provided.