Determination of 25 EDS in Frog and Fish Tissue by GC-MS (SIM)

Ueon-SangShin,Ho-SangShin 대한화학회 2003 Bulletin of the Korean Chemical Society Vol.24 No.4

Model-Predictive Direct Power Control With Vector Preselection Technique for Highly Efficient Active Rectifiers

Sangshin Kwak,Jun-Cheol Park IEEE 2015 IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS - Vol.11 No.1

<P>This paper proposes a novel method to reduce switching losses on the basis of a model-predictive direct power control (MPDPC) method for ac-dc active rectifiers. The main idea is to preselect voltage vectors to decrease switching losses at the next sampling period, and then select one optimum voltage vector among only the preselected voltage vectors to perform direct power control (DPC). The proposed vector preselection scheme enables a predefined cost function to consider only four vectors to control the real and the reactive power at every sampling period. The proposed MPDPC method using only the four preselected vectors stops switching operation of one leg exposed to the largest input current at every sampling period. On the basis of the preselected vectors at each sampling period, the proposed method can effectively reduce the switching losses, as well as accurately perform power control of the active rectifier.</P>

Phase-Redundant-Based Reliable Direct AC/AC Converter Drive for Series Hybrid Off-Highway Heavy Electric Vehicles

Sangshin Kwak,Taehyung Kim,Gwangmin Park IEEE 2010 IEEE Transactions on Vehicular Technology VT Vol.59 No.6

<P>Hybrid electric vehicle (HEV) technology has numerous advantages over conventional vehicles, from standpoints of fuel economy, energy independence, and environmental concerns. Effective solutions for HEVs have been expanding their applications over highway vehicles, such as sedans and sport utility vehicles, into a variety of traditional vehicles. HEV systems applied to off-highway heavy-duty vehicles, which are operated by an engine, a generator, and traction motors, are investigated in this paper. This paper explores the use of a direct ac/ac converter for off-highway heavy-duty HEVs, which can directly drive traction motors from the generator with no intermediate dc conversion. In addition, a phase-redundant matrix converter structure with a backup leg and a control scheme is proposed to guarantee reliable and safe vehicle operations by providing continuous disturbance-free operations against converter faults. Fault-diagnosis techniques using line-to-line and phase voltages are presented not only to detect system malfunctions but to locate a failed switching device among 18 switching components as well. Appropriate reconfiguration structure and control actions with accurate knowledge about fault occurrence can avoid propagation of fault, which may lead to a catastrophic system failure.</P>

Predictive Current Control Methods With Reduced Current Errors and Ripples for Single-Phase Voltage Source Inverters

Sangshin Kwak,Soo-Eon Kim,Jun-Cheol Park IEEE 2015 IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS - Vol.11 No.5

<P>This paper proposes two model predictive current control (MPCC) methods utilizing two output voltages with variable application durations in one sampling period to control the output currents of single-phase voltage source inverters (VSIs). In the proposed methods, the application durations of the two voltages, as well as the selection of two output voltages used in the future sampling period, are determined by an optimization process to minimize current error inside the future sampling period and to eliminate current error at the end of the future sampling instant. By utilizing the two voltages with variable durations, the two proposed MPCC methods can reduce steady-state current errors and decrease output current ripples without increasing the sampling frequency in comparison with the conventional MPCC method, despite only three distinctive output voltages being allowed in the single-phase VSI. The two proposed methods along with the conventional MPCC method are compared in terms of current errors and total harmonic distortion. The effectiveness of the two proposed methods for the single-phase VSIs is verified with both simulation and experimental results.</P>

Predictive-Control-Based Direct Power Control With an Adaptive Parameter Identification Technique for Improved AFE Performance

Sangshin Kwak,Un-Chul Moon,Jun-Cheol Park Institute of Electrical and Electronics Engineers 2014 IEEE transactions on power electronics Vol. No.

<P>This paper proposes predictive-control-based direct power control (DPC) with an adaptive online parameter identification technique for ac-dc active front ends (AFEs) to overcome model mismatch and parameter uncertainty. Based on least-squares estimation, the input inductance and input resistance of the AFE are calculated every sampling period using sampled input currents and input voltages. Because the online-tuned input inductance and resistance are updated for the controller, the proposed predictive-control-based DPC with the adaptive parameter identification technique can mitigate performance degradation resulting from the model uncertainty of the model predictive controller without any additional sensors. Therefore, the AFE generates sinusoidal input currents with a unity power factor despite parameter uncertainty.</P>

Switching Strategy Based on Model Predictive Control of VSI to Obtain High Efficiency and Balanced Loss Distribution

Sangshin Kwak,Jun-Cheol Park IEEE 2014 IEEE transactions on power electronics Vol.29 No.9

<P>This paper proposes the switching strategy based on finite control set model predictive control (FCS-MPC) method, to reduce switching losses and obtain balanced loss distribution of the voltage-source inverters (VSIs). Unlike the conventional FCS-MPC method with no explicit information of the reference voltage, the developed voltage-based FCS-MPC scheme produces the future reference voltage vector with the Lyapunov function every sampling period. With information of both the future reference voltage and the future load current vectors, the proposed switching strategy instantaneously determines one optimum clamped phase among the three legs in the VSI every sampling period. By optimally determining the clamping phase and its duration on the basis of every sampling period, the proposed switching strategy can successfully reduce the VSI switching losses. In addition, the proposed switching method can yield a balanced loss distribution among the switches in the VSI, contrary to the conventional FCS-MPC. The balanced loss generation as well as the switching loss reduction by the proposed method, which is optimal at the sampling period scale, is directly incorporated with the platform of the FCS-MPC algorithm, since the FCS-MPC operates on the basis of the sampling period. Thus, the proposed switching operation based on the voltage-based FCS-MPC algorithm enables the future VSI output currents to track the future reference current vector, as well as results in the reduced switching losses and the balanced loss performance.</P>

Predictive Control Method With Future Zero-Sequence Voltage to Reduce Switching Losses in Three-Phase Voltage Source Inverters

Sangshin Kwak,Jun-Cheol Park IEEE 2015 IEEE transactions on power electronics Vol.30 No.3

<P>This paper proposes a predictive control method with zero-sequence voltage injection to efficiently reduce the switching losses of three-phase voltage source inverters (VSIs). In the proposed predictive control method, three-phase future voltage references modified by a zero-sequence voltage injection are generated to clamp one of the three legs with the largest load current. Furthermore, the future zero-sequence voltage, which is produced online with the future voltage and current references in every sampling period, optimally adjusts the clamping duration on each leg, depending on the load angle. In addition, the proposed method selects the zero vector on the basis of the polarity of the future zero-sequence voltage to reduce the switching losses. Using a predefined cost function, the proposed predictive control scheme chooses one optimal voltage state closest to the future voltage references modified by the zero-sequence voltage injection. Therefore, the proposed predictive control method can perform load current control and minimize the switching losses of the VSI under any load condition regardless of the load angle.</P>

Deep Learning-Based Multi-Hop Data Transmission Schemes

Sangshin Park,Hoon Lee 한국통신학회 2022 한국통신학회 학술대회논문집 Vol.2022 No.6

Model Predictive Control Methods to Reduce Common-Mode Voltage for Three-Phase Voltage Source Inverters

Sangshin Kwak,Sung-ki Mun IEEE 2015 IEEE transactions on power electronics Vol.30 No.9

<P>In this paper, we propose model predictive control methods to reduce the common-mode voltage of three-phase voltage source inverters (VSIs). In the reduced common-mode voltage-model predictive control (RCMV-MPC) methods proposed in this paper, only nonzero voltage vectors are utilized to reduce the common-mode voltage as well as to control the load currents. In addition, two nonzero voltage vectors are selected from the cost function at every sampling period, instead of using only one optimal vector during one sampling period. The two selected nonzero vectors are distributed in one sampling period in such a way as to minimize the error between the measured load current and the reference. Without utilizing the zero vectors, the common-mode voltage controlled by the proposed RCMV-MPC algorithms can be restricted within ±Vdc/6. Furthermore, application of the two nonzero vectors with optimal time sharing between them can yield satisfactory load current ripple performance without using the zero vectors. Thus, the proposed RCMV-MPC methods can reduce the common-mode voltage as well as control the load currents with fast transient response and satisfactory load current ripple performance compared with the conventional model predictive control method. Simulation and experimental results are included to verify the effectiveness of the proposed RCMV-MPC methods.</P>

음성 인식 기반의 방송미디어 디바이스 제어 및 편집 시스템 구현

오상신(Sangshin Oh),정수환(Soo-Whan Chung),강홍구(Hong-Goo Kang) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.11