Annual Report Annual Report - Power Electronics Lab -

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3 Annual Report 2018 Annual Report - Power Electronics Lab -

4 Contents 1. Lab Introduction Professor Introduction Laboratory Information Laboratory Location Research Area Research Equipment Holdings Contents 2. Project Contents Development of Single-Phase Charging Control Logic for On-board Charger Using Motor & Inverter Study on the SST Core Technology for the LVDC Distribution (Development of Bi-Directional MVAC-MVDC Circuit) Development of Sub-Module Test Equipment and High-Voltage Insulated Power Supply for MMC VSC HVDC Development of dual low voltage DC(DLDC) System for Electric Bus Development of Power Generation and Its Control System by Replacing Hydraulic Differential Pressure Valve Development of High Performance Control and Improved Reliability in Matrix Converter System Study of Significance Device Model and Reliability Evaluation for MVDC Distribution System Survey of Motor-Inverter Control Algorithm Development of 3-Level Power Conversion System Control Algorithm for Energy Storage System Study of Environment Composition for Propulsion Power Converter Controller S/W Platform Investigation of 3-Level Hybrid ANPC Inverter Based on SiC MOSFET and Si IGBT 3. Research Results

5 Lab Introduction Professor Introduction Prof. Kyo-Beum Lee Tel : Woncheon hall Rm 303 kyl@ajou.ac.kr Education ( ) B.S in Electrical and Electronic Engineering, Ajou University, Suwon, KOREA ( ) M.S in Control and Instrumentation Engineering, Ajou University, Suwon, KOREA ( ) Ph.D in Electrical Engineering, Korea University, Seoul, KOREA 1.Editors Associate Editor, IEEE Transactions on Power Electronics (2006- ) Associate Editor, Journal of Power Electronics (2009- ) Associate Editor, IEEE Transactions on Industrial Electronics ( , 2018-) Associate Editor, Journal of Electrical Engineering & Technology (2015- ) Associate Editor, International Journal of Power Electronics (2016~) Editor-in-Chief, Power Electronics Section, Electronics (2018-) 2. Reviewers IEEE Transactions on Industry Applications, Industrial Power Converter Committee IEEE Transactions on Industry Applications, Industrial Drive Committee IEEE Transactions on Power Electronics IEEE Transactions on Industrial Electronics IEEE Transactions on Energy Conversion IEEE Transactions on Aerospace and Electronics Systems IEE Electronics Letters IEE Proceedings-Electric Power Applications Journal of Electrical Engineering Journal of Science and Engineering Iranian Journal of Electrical and Computer Engineering International Journal of Control, Automation, and Systems Journal of Electrical Engineering & Technology Journal of Power Electronics, etc. 3. Activities Senior Member of IEEE (Power Electronics, Industrial Electronics, Industry Applications, and Power & Energy - Society) Member of KIPE (Korean Institute of Power Electronics) and KIEE (Korean Institute of Electrical Engineers) Industrial Electronics Society Technical Committee on Renewable Energy Systems IEEE ISIE2010 (International Symposium on Industrial Electronics) track on Power Electronics - Track Chair IEEE CASE2010 (Conference on Automation Science and Engineering) track on Automation in Green Technology - Track Organizer ICPE2011 (International Conference on Power Electronics)-ECCE Asia topic on Power Quality and Energy Saving Technology - Topic Chair IEEE ISIE2013 (International Symposium on Industrial Electronics) track on Power Electronics - Track Chair ICEMS2013 (International Conference on Electrical Machines and Systems), Technical Program Committee Co-Chairman IEEE CENCON2014 (Conference on Energy Conversion), International Advisory Committee Member ICPE2015 (International Conference on Power Electronics)-ECCE Asia, Technical Program Committee Vice Chair IEEE CENCON2015 (Conference on Energy Conversion), International Advisory Committee Member CPE-POWERENG2016 (Joint Conference - 6th International Conference on Power Engineering, Energy and Electrical Drives, and 10th International Conference on Compatibility and Power Electronics), Technical Program Chair (Electro-Mechanical energy Conversion) IEEE IECON2016 (Annual Conference of IEEE Industrial Electronics Society) track on Grid Connected Converters - Track Chair IEEE PECON2016 (International Conference on Power and Energy), International Advisory Committee Member IEEE CENCON2017 (Conference on Energy Conversion), International Advisory Committee Member ICEE2018 (24th International Conference on Electrical Engineering), Local Organizing Committee Member

6 Lab Introduction About the laboratory Laboratory Information The Power Electronics Laboratory (PEL) is located in the Woncheon-hall 435 at Ajou University. The primary objective of the PEL is to develop new technologies in the area of power electronics. We are conducting research on E.V., motor drives, and grid & renewable energy systems. We are also concerned with developing control algorithms and system topologies as well as applying them into the industrial fields. In addition, a significant fraction of our research is devoted to development of advanced motor and system control algorithms, efficiency increment methods and micro/smart grid technologies. Some of the current areas of interest include : Advanced inverter and converter technologies for the Electric Vehicle system Sensorless vector control, advanced DTC, and torque predictive control for machine driving Fault diagnosis and tolerant control Grid control for renewable energy systems Detailed descriptions of our work are available in the publications posted on our web site: pel.ajou.ac.kr For further information, please contact our lab advisor: Prof. Kyo-Beum Lee < 2018 Members of Power Electronics Laboratory >

7 Lab Introduction Professor Kyo-Beum Lee Assistant Professor Ibrahim Mohd Alsofyani Laboratory Information Research Professors Sungjoon Cho, Sze Sing Lee Research Associate Anto Joseph Researchers Yeongsu Bak, Seok-Min Kim, Kyu-Chul Bae, Laith M. Halabi, Jae-Jin Lee, Joon-Young Park, Hak-Seung Ro, Won-Seok Jung, Duk-Ho Lee, Bong-Hyun Kwon, Ho-Hyun Kang, Dongho Choi, Keon Young Kim, Yoon Jang, Dong Woo Seo, Seung-Rae Jo, Ho-Sung Kang, Leticia A. Adase, Samer S. E. Hakami, Young-Jae Lee, Ki-Seok Sung, Sung-Won Kim, Ki-Hoon Kwon, Heung-Seok Park, Jeong-Min Kim, Ki-Deuk Lee, Sea-Won Kim, Geum-Bok Mun, Sang-Sin Han, Young-Deuk Kim, Ye-ji Kim, Sang-Hun Kim, Sang-Won An, Chan Hwangbo, Eui-jae Lee, Byeol Han, Seong-Su Cheon, Min-Geun Song Administrative Staff Seong-Sook Hong

8 Lab Introduction Alumni Laboratory Information Name Company Name Company Ph.D Yee Kyu Kang LIG Nex1 Co.,Ltd. Hae-Gwang Jeong LG Electronics Dong Keun Yoon LG Innotek Co.,Ltd. Dae-Keun Choi Hyundai Transys Sang Hyouk Lee LG Innotek Co.,Ltd. Kiwoo Park LSIS Co., Ltd. Dae Il Son LG Electronics Young Jong Ko Kiel University (Germany) Sun Min Kim Hitachi-LG Data Storage Korea, lnc. June-Seok Lee KRRI (Korea Railroad Research Institute) Dae-Min Jang SamsungElectro-Mechanics Eunsil Lee - Se-Ho Lee Samsung Electro-Mechanics Ui Min Choi Professor in Seoul National University of Science and Technology Jong-Kyu Kim LIG Nex1 Co.,Ltd. Seok-Kyoon Kim Professor in Hanbat University Hyun Hee Lee LG Electronics Byoung-Seoup Lee Iosystem Gwang Seob Kim Hyundai Motor Company Yongsoo Cho LG Electronics Jong Hyun Lee Hyundai Electric Seung Koo Baek KRRI (Korea Railroad Research Institute) YongMo Jin KEPCO Plant Service & Engineering Hye-Ung Shin Ssangyong Motor Company YoungJun Kim Jae Seung Yoon Yejun Patent & Trademark Law Firm/ Patent Attorney Institute Jae Hwang Kwak Suwon Information Science Highschool Computer Electronic Department Teacher Secu-line Co. Jin-Hyuk Park KRRI (Korea Railroad Research Institute) Dong-Hee Kim Hyundai Elevator Co. June-Hee Lee KRRI (Korea Railroad Research Institute) Hak-Seung Ro Hyundai Elevator Co. Master Jung-Hyun Kim ADT Co. WonSang Kim Samsung Heavy Industries Yesl Shin LG Electronics Gyunghun Sim Mando Jae Jin Lee Sung Chang Telecom Co.,Ltd Seo Hyung Kim Mando Seong-Soo Park LG Innotek Co.,Ltd. Kil Hun Kim LIG Nex1 Co.,Ltd. Ji A Yang Korea Water Resource Corporations Dong Sun Park LIG Nex1 Co.,Ltd. KwangHun Chang Hankuk Engineering Consultants Sol bin Lee LG Electronics Jae-Ho Park Korea Testing Certification Duk Hong Kang Seoul Metro YoungBeom Lee Korea Testing Certification

9 Lab Introduction Alumni Laboratory Information Name Company Name Company Dae Hwan Kim Ds-electron Co.,Ltd Seok-Min Kim Ph.D Student in Ajou University SiYoung Lee Korea Testing Certification Rae-Ho Kwak Hyundai Autron KangMin Han KEPCO Plant Service & Engineering Co.,Ltd Seung-Gyu Seo LG Electronics Won Seok Cho Korea Testing Certification Seong-Yun Kang Dawonsys (Military Service) Ju-Hye Kim Poongsan R&D Institute Min-Ho Ahn Hyundai Autron Man-Woo Jang Korea Testing Certification In-Jung Won Hyundai Autron Bong Kyun Shin Korea Testing & Research Institute Ji-Ook Sin LS Mecapion Sang-Ho Moon Hyundai Mobis Song-Hee Yang LG Electronics Tae-Min Yoon LG Electronics Jae-Won Lee Ssangyong Motor Company Hyun-Woo Sim Hyundai Mobis Jae-Yoon Cho Vector Korea IT, Inc. Yong-Gyu Song Hansol Technics Co.,Ltd Hyun-Cheol Moon Hanwha Systems Hyung Kim Samsung Electronics Han-Rim Lee LS Mecapion Sung-Tak Jou OKY Min-Gyo Jeong New Power Plasma (Military Service) Kyoung-Gu Lee Dawonsys Hyo-Chul In EGtronics (Military Service) Kyun-Seon Ji Ph.D Student in Nagoya Institute of Technology (Japan) Tcai Anatolii Ph.D Student in Kiel University (Germany) Jun-Sung Kim Korea Testing Certification Hyeong-Seok Han KATECH Dae-Joong Kim LG Electronics Byung-Yong Jeon Korea Testing Certification Yeong-Su Bak Ph.D Student in Ajou University Seong-Soo Park LG Innotek Co. Seung-Joo Lee LG Electronics Yong-Dae Kwon Ph.D Student in Kiel University (Germany) Seung-Jong Yoo LG Electronics Young-Seol Lim Hyundai Motor Company Won-Seok Jung Korea Southern Power Co.,Ltd Ho-Pyo Sohn CORE Co. Ltd (Military Service) Dong-Yeob Han Microchip Technology Byeong-Gyu Kang LSIS Co. Ltd

10 Lab Introduction Laboratory Location Laboratory Location Power Electronics Lab : Woncheon hall Rm 435 < Woncheon hall Rm 435 > Power Conversion R&D Center : Namgyeong building 2F < Namgyeong building 2F >

11 Lab Introduction Research Area Research Area The PEL (Power Electronics Laboratory) carries out research mainly in four areas; closely related to the use of power electronics, which include: 1. Electric vehicle Power electronics systems play an essential role in electric vehicles. The power electronic systems is employed in battery charging, battery management, and propulsion. The power electronic systems are utilized mainly to efficiently charge the DC power source i.e., battery systems, and to effectively convert this energy into motor drives. 2. Motor drives In many industry applications, motors are used for factory automation. Our research is seeking solutions to effective control of motors such as AC, DC, SRM, etc. Some of the methods used for driving motors are flux weakening control, position/speed sensorless control, direct torque control, etc. 3. Reliability Increasing efforts have been put into making power electronic systems better in terms of reliability to achieve high power source availability and also reduce the cost of maintenance. Fault diagnosis and tolerant control techniques are studied for IGBT, current sensor, voltage sensor and DC-link capacitor for the converter. 4. Renewable energy system In renewable energy system, the power electronics are used for controlling the renewable source and interfacing with the load which can be either grid-connected or stand-alone mode. The renewable energy can be wind energy, solar energy and fuel cell, etc. < Research area > < Renewable energy system > < Electric vehicle >

12 Lab Introduction Research Equipment Holdings Research Equipment Holdings 1. Oscilloscope Lecroy, Wave Runner 104MXi, 1GHz, 10GS/s Lecroy, Wave Runner 64MXi, 600MHz, 10GS/s Yokogawa, DLM MHz, 2.5GS/s Tektornics, DPO3014, 200MHz Tektornics, DPO2014, 200MHz Lecroy, HDO8108, 1GHz, 2.5GS/s Lecroy, HDO6104, 1GHz, 2.5GS/s 2. Amplifier Tektronix, TCPA 300, DC 30A, 100MHz 3. Current probe Power Supply Yokogawa, < Yokogawa, WT3000, Power Analyzer > 4. Digital Multimeter Kyoritsu, KEW 1061 Fluke, 116 TRUE RMS MULTIMETER 5. Electric Power Analyzer N4L, Precision Power Analyzer PPA5530 Yokogawa, Power Analyzer WT RLC Meter Philips, PM6304 Keysight Technologies, Impedance Analyzer E4991B < Keysight Technologies, E4991B, Impedance Analyzer > 7. Load Daunanotek. CO. LTD, RLC 3P LOAD Daekyeong. CO. LTD, 6kW/13kW resistance load Daekyeong. CO. LTD, 10kW braking load Daekyeong. CO. LTD, DBRL-STF 5kW 40ohm Daekyeong. CO. LTD, 8kW/24kW resistance load KIKUSUI, 12kW DC Electronic Load PLZ12005WH 8. Digital Indicator Senstech. CO. LTD, DI-10W 9. Dynamic Braking Unit Daekyeong. CO. LTD, DBUH037-2L 10. Inverter Yaskawa, CIMR-G7A4P5, Varispeed G7(400V-5.5kW) RS Automation, CSD5 Single Axis Servo driver 1kW Yaskawa, CIMR-ACA45P5, Varispeed AC(400V-5.5kW) < KIKUSUI, PLZ12005WH, 12kW DC Electronic Load >

13 Lab Introduction Research Equipment Holdings Research Equipment Holdings 11. DC Power Supply Chroma, DC Power Supply 62959H-600 SM Techno, AC220V, 3A, 60Hz Hanil Electric, HPS-303D, AC220V, 3A, 60Hz HC2330A, AC220V, 220V, 3A, 60Hz GW Instek, GPS-3303 Regatron TopCon TC.GSS Programmable Grid-tie Source Sink Bidirectional High Power DC 600VDC, 40A 12. Slidac Daelimec, VARIAC, 220V, 12A, 3kAV Myungseong Electric, 40kVA Slidac TJ Tek Slidacs, 220/300V, 60Hz, 4kW Daelimec, Slidacs, 380V, 21A, 15kVA, 60Hz, More than 95% efficiency 13. Electric Transformer Hanil Trans, 460/575Vrms Electric Transformer 14. Simulator Green Power Tech. CO. LTD, PV Simulation Ajou Control Application Lab, Wind Power California Instrument, Grid Simulator, 380V, 30KVA, MX 30-3Pi-380-SNK 15. Motor Hyosung, High efficiency 3-phase induction motor Hyundai Heavy Industries, HL165SR202ERDS, 15kW, 4P, 220/380V, efficiency 89% Hyundai Heavy Industries, Induction Motor 3.7kW, voltage: 220/380V, current: 13.8A Hyundai Heavy Industries, Induction Motor 5.5kW, voltage: 220/380V, current: 21/12A Yaskawa, SSR1-4011AFN, 373V, 19.9A, 87.5Hz, 11kW, PF=94 Yaskawa, SSRI-2011BFN, PF=0.95, 191V, 72.5Hz, 38A, 11kW Lery Somer, 3-phase Asynchronous motor Lery Somer, 142EZD300CACAA, BLAC Servo motor Yaskawa, SGMGH-1AACA61, BLAC Servo motor Komotek, KBNZ-10BE1NE 16. Torque Transducer Senstech. CO. LTD, SBM-10K, BLAC Servo motor 17. Controller Myungseong Electric, MS180P3(Speed Control) Control Techniques, SP2203 UNIDRIVE 18 EMI Analyzer EMCIS, EA-300, 9kHz~300MHz < Grid Simulator > < DC Power Supply >

14 1. Development of Single-Phase Charging Control Logic for On-board Charger Using Motor & Inverter Project leader Seok-Min Kim ( 김석민 ) B.S in Department of Electronic Engineering, Sejong University, Seoul, KOREA M.S in Department of Space Survey Information Technology, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Dongho Choi ( 최동호 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ho-Sung Kang ( 강호성 ) B.S in Department of Electrical Engineering, Sangmyung University, Seoul, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of an integrated charging system for the hybrid electric vehicle using electric motor and its inverter - Design of a single-phase on-board charger (OBC) using hybrid starter generator system of the hybrid electric vehicle - Development of a relay control system for switching between charging mode and driving mode - Validation of the operation of a conventional hybrid starter generator, motor driving and regenerative braking Control method of AC-DC converter for single-phase OBC (H-bridges) - Development of the control algorithms with H-bridges (Phase locked loop, voltage controller and current controller) - Compensation of low order harmonics (Non-ideal PR controller, PI controller) Control method for battery charging using DC-DC Buck converter 2. Analysis of power density enhancement using the proposed charging system Power converter circuit of the conventional hybrid electric vehicle and electric vehicle - Separate system configuration of the hybrid starter generator system and battery charging system The proposed single-phase OBC using motor with its inverter - Higher power density is achieved < Block-diagram for operation of proposed charging system >

15 1. Development of Single-Phase Charging Control Logic for On-board Charger Using Motor & Inverter Project Contents 3. Simulation results < Simulation waveform (DC-link voltage control)> < Simulation waveform (Battery voltage control)> 4. Experimental Setup Grid system simulator (Supplying a 220 V rms /60 Hz grid voltage to load) Lithium ion battery module (360 V battery pack) Motor and Generator coupled set (8.8 kw IPMSM (Target) and 15 kw Induction machine (Load)) 5. Experimental results < Experimental setup > Battery Pack M-G set < Experimental waveform (G2V mode)> < Experimental waveform (V2G mode)>

16 2. Study on the SST Core Technology for the LVDC Distribution (Development of Bi-Directional MVAC-MVDC Circuit) Project leader Seok-Min Kim ( 김석민 ) B.S in Department of Electronic Engineering, Sejong University, Seoul, KOREA M.S in Department of Space Survey Information Technology, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Min Gyo Jeong ( 정민교 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Hyo Chul In ( 인효철 ) B.S in Department of Electrical Engineering, Doowon Technical University, Anseong, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Project Aim - Establishment of MVAC-MVDC and HVDC converter technologies applicable to DC power distribution system Project objective for 1 st year: Development of MVAC-MVDC converter circuit - Topology survey for the MVAC-MVDC converter - Development of simulation model for Modular Multilevel Converter (MMC) - Development of control algorithms for MMC system Project objective for 2 nd year: Development of bidirectional isolated DC-DC converter circuit - Development of simulation model for bidirectional high-voltage DC-DC converter circuit - Implementation of bidirectional high-voltage DC-DC converter circuit - Development of control algorithms for bidirectional high-voltage DC-DC converter circuit 2. MMC (Modular Multilevel Converter) The MMC is suitable for power conversion of high- or medium-voltage application due to its modularity (easy construction, assembling and flexibility in converter design). Multilevel waveform is expandable to any number of voltage levels to reduce total harmonic distortion Development of simulation model - The algorithm for sub-module capacitor voltage balancing control is essential to improve the performance of MMC system. < Schematic diagram for the project goal > < 3-phase MMC topology >

17 2. Study on the SST Core Technology for the LVDC Distribution (Development of Bi-Directional MVAC-MVDC Circuit) Project Contents 3. Development of control algorithm for the MMC Development of control algorithm for the grid-connected system - Current controller design - Design of DC-link voltage controller for the DC-AC power conversion - The optimal sequence for the MMC with grid-connected system is required to achieve the stable initial control operation with balanced capacitor voltages among the modules. Development of switching method to enhance power conversion efficiency - Insertion of additional clamping intervals for each sub-module in MMC without changing the reference for each arm. - Establishment of novel discontinuous modulation method that maintained output quality with switching losses reduction. < AC-DC control sequence and results> < Simulation results for high efficiency modulation > 4. Multilevel DC Transformer (MDCT) Multilevel high-frequency-link DC transformer by using MMC - Composed of MVDC link, multilevel high-frequency link, and LVDC link - MVDC link consists of single phase MMC with n SMs per arm and high frequency arm inductor - LVDC link is composed of m full-bridges and high frequency isolated transformers. Development of simulation model for the MDCT Development of alternate modulation balance algorithm (AMBA) - Rotate the switching patterns among the SMs and full-bridges for every switching time - Realize the algorithm by rotating the triangular carrier signals which take charge of each SM and full-bridge MVDC Link VMV n Modules/Arm n Modules/Arm Multilevel high-frequencylink ibcm ibc2 ibc1 Hm H2 H1 m Full-Bridges VLV LVDC Link < MDCT topology > < Simulation results for MDCT with AMBA >

18 3. Development of Sub-Module Test Equipment and High-Voltage Insulated Power Supply for MMC VSC HVDC Project leader Sungjoon Cho ( 조성준 ) Ph.D Candidate in Department of Electrical Engineering, Korea University, Seoul, KOREA He worked in Hyundai Heavy Industries co. ltd in power conversion department as a head researcher. Seok-Min Kim ( 김석민 ) B.S in Department of Electronic Engineering, Sejong University, Seoul, KOREA M.S in Department of Space Survey Information Technology, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ho-Sung Kang ( 강호성 ) B.S in Department of Electrical Engineering, Sangmyung University, Seoul, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of thermal model of IGBT modules in modular multilevel converters (MMCs) - Analysis of instantaneous power losses of IGBTs depending on the arm current - Development of thermal estimation method at fundamental frequency of arm current Development of power cycling test equipment - Design of small-scaled power cycling test equipment - Development of control algorithms for the power cycling test set-up - Verification of the control method through the experiment 2. Research necessity The reliability of the power conversion system is one of the most important issues for the system efficiency. The potential of the semiconductor failure is especially increased because of the large number of devices in MMC. It is important to estimating the thermal stresses in IGBT which is dependent on instantaneous power losses. The investigation of thermal stress distribution is essential for cooling systems design and estimating life-time of devices < Percentage of the most fragile components > < Equivalent loss curves for devices in an SM >

19 3. Development of Sub-Module Test Equipment and High-Voltage Insulated Power Supply for MMC VSC HVDC Project Contents 3. Power cycling test equipment topology for MMC sub-module Composed of two half-bridge converters with load inductor and cooling system - Two half-bridge converters are divided to test converter and load converter - AC and DC components in the output current of test converter are controlled independently Hardware setup for the power cycling test - Verify the power cycling test topology and its control algorithms through the hardware experiments - DC-link voltage: 300 V (max. 800 V) - Rated Current: 30 A rms (0.1 ~ 120 Hz) - Control: TMS320F28335 (TI co.) < Expected structure of power cycling equipment > < Prototype of IGBT mount board > 4. Control algorithms for the power cycling test equipment Control the equipment to design the similar experimental circumstance with real condition of MMC system - Test converter and load converter are independently controlled. Test converter - Sub-module current control (magnitude and frequency of current and power factor control) Load converter - Sub-module voltage control (magnitude and frequency of voltage) - Realize the algorithm by rotating the triangular carrier signals which take charge of each SM and full-bridge The arm current in the sub-module is generated by using the PI and PR controller < Structure of IGBT module > < Control block diagram for the test equipment > < Load current control simulation results >

20 4. Development of dual low voltage DC(DLDC) System for Electric Bus Project leader Yeongsu Bak ( 박영수 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Dong Woo Seo ( 서동우 ) B.S in Department of Electronics and Radio Engineering, Kyung Hee University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Sang-Won An ( 안상원 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of dual low voltage DC to DC(DLDC) converter system for electric bus - Development of DC to DC converter using 5.8kW isolated full bridge converter and 12kW non-isolated buck converter - Design of center-tap transformer and L-filter to increase efficiency and reduce current harmonics 2. Research necessity A DLDC system is developed for electric bus application. The DLDC system is combined two Low voltage DC-DC converter system. The DC voltages of 360 V with power rating of 12 kw and 28 V with power rating of 5.8 kw are generated from a high-power battery pack (538 V~828 V). As electric bus is powered by high-power battery pack, the DLDC can be used to support electrification within the bus. The 12 kw LDC system is used for air conditioning compressors in cooling system. The 5.8 kw LDC system is used for air conditioning system, lighting devices, multimedia devices and vehicle control devices. The DLDC system achieved high power conversion efficiency. 3. System specification and configuration Item DLDC System parameter 360 V LDC 28 V LDC function Input voltage DC 538 / 706 / 828 V DC DC 538 / 706 / 828 V DC UVP Output Voltage DC 360 V DC DC 28 V DC OVP Rated output 12 kw 5.8 kw OCP Efficiency 90 % 90 % SCP Power density Size 0.45 kw/l 565 X 479 X 146 (mm) < System parameters > < System configurations >

21 4. Development of dual low voltage DC(DLDC) System for Electric Bus 3. Development of dual low voltage DC to DC (DLDC) converter system for electric bus Development of a modulation technique for full-bridge converter and buck converter Development of a control algorithm : current control and voltage control Design and development of a center-tap transformer and L-filter Verification of experimental set 4. Hardware configuration and experimental results < experimental control board > < designed transformer and L-filter> Input voltage : 828 V Output voltage : 360 V Output current : 33.3 A Input current : 14.5 A < 28V LDC simulation circuit > Inductor current ripple : 4.41 A Average inductor current : 33.3 A V A 0.6m A V W kwh < 28V LDC simulation result > V_in V 706 A A 3000u W/kWh V V_out Input voltage : 828 V Output voltage : 360 V < 360V LDC simulation circuit > Output current : 33.3 A Input current : 14.5 A Inductor current ripple : 4.41 A Average inductor current : 33.3 A PWM A [High side] PWM B [High side] PWM A [Low side] PWM A [Low side] < 360V LDC simulation result > < 28V LDC PWM result >

22 5. Development of Power Generation and Its Control System by Replacing Hydraulic Differential Pressure Valve Project leader Yeongsu Bak ( 박영수 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Keon Young Kim ( 김건영 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Young-Jae Lee ( 이영재 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of power conversion system for generating electrical energy from unused fluid energy using hydraulic turbine in the differential pressure valve when the fluid (raw water or thermal energy) is supplied by the pipe (or heat transfer pipe) Development of product that can reduce the purchase cost and maintenance cost of foreign valve by extending the replacement cycle through replacement of existing pressure regulating valve system with a hydraulic turbine generator Development of products capable of saving energy and generating profit through development of power conversion system utilizing differential pressure energy Development of high-temperature 5kW capacity volumetric hydraulic generator combined with differential pressure control and flow measurement - Numerical optimization design to improve the performance such as high efficiency and pressure pulsation reduction of volumetric hydraulic generator - Design to improve the accuracy of flow control and measurement of volumetric hydraulic generation - Development of a business model based on performance test evaluation and demonstration test of volumetric hydraulic generation Development of power conversion system using hydraulic power generation - 5kW power generation system, 5kW grid-connected system, and 5kW power supply system 2. Research necessity The hydraulic lift generated by the supplying the fluid (raw water or thermal energy) in the pipe (or heat transfer pipe) is a technology that recovers energy by utilizing the pressure difference (differential pressure energy) controlled by the pressure control valve installed in the district heating heat transfer pipe network The heat transfer network in district heating uses a system that protects user equipment from high pressure fluid and regulates or reduces pressure through the valve for remote supply of fluid The pressure control valve causes cavitation due to the use of high-pressure fluid. It causes many problems such as malfunctions, causing energy loss and complaints Therefore, hydraulic power generation system, which is a developed product, produces electricity by recovering and utilizing the unused differential pressure energy through the replacement of the pressure control valve and it secures the economical efficiency

23 5. Development of Power Generation and Its Control System by Replacing Hydraulic Differential Pressure Valve 3. Total system < Total system diagram > < IPMSG and hydraulic turbine experimental set > 4. Hardware configuration 5kW DC/AC inverter of generation system with LCD panel, 5kW bidirectional AC/DC converter of grid-connected system, 5kW DC/AC inverter of power supply system, and electromechanical system such as interior permanent magnet synchronous generator (IPMSG) and hydraulic turbine < Generation system > < Grid-connected system > < Power supply system > 5. Experiment results < Sensorless vector control for generation & power supply system > < Restart control for generation system >

24 6. Development of High Performance Control and Improved Reliability in Matrix Converter System Project leader Yeongsu Bak ( 박영수 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Dongho Choi ( 최동호 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ye-Ji Kim ( 김예지 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of boost-type matrix converter and reliability improvement algorithm - Design of 3-phase matrix converter systems - Boost operation of matrix converter and control algorithm - Fault detection and tolerance operation in matrix converter systems - Design of multi output matrix converter systems 2. Research and development contents Design of 3-phase matrix converter systems - Literature on existing technologies related to matrix converter design and development of DSP control board - Development of optimal filter, protection circuit, and design technique - Validation of basic operation and rate test of matrix converter system Boost operation of matrix converter and control algorithm - Development of matrix converter simulation and technique for voltage-boosting - Development of voltage-boosting algorithm and control technique of overmodulation - Validation of voltage-boosting function, high performance and efficiency control Fault detection and tolerance operation in matrix converter systems - Development of the existing methods and fault detection techniques related to the causes and effects of power device failure - Model development of imitating failure for a switch and gate driver - Demonstration of the imitating failure for switch and gate driver Design of multi output matrix converter systems - Literature on existing technologies of multi output system for matrix converter - Design of multi output system and development of independent control for each load - Validation and improvement control techniques of multi output system 3. Development results Securing Intellectual Property right through patents and publications of matrix converter system Training expert of matrix converter system for cutting-edge research Applications for patents regarding the performance optimization of matrix converter

25 6. Development of High Performance Control and Improved Reliability in Matrix Converter System 4. Validation of basic operation and rate test of matrix converter system Experimental setup is composed of a control board, power conversion prototype, and sensors - Control board is located at the top of the setup, which is composed of a digital signal processor (DSP) using the TMS320C28346 and a field programmable gate array - Power conversion prototype is located in the middle of the setup, which is composed of the rectifier stage and the inverter stage using the insulated gate bipolar transistors (IGBTs) and gate drivers - Voltage and current sensors are located in the bottom of the setup < Experimental setup > < Basic operation of matrix converter system > 5. Development of voltage-boosting algorithm Output line-to-line voltage of the matrix converter is larger than input line-to-line voltage achieved by voltageboosting algorithm. PMSM of output stage is controlled with a constant speed at 4-N m load torque using the matrix converter < Input-output voltages and DC-link voltage > < PMSM is controlled to a constant speed > 6. Validation and improvement control techniques of multi output system < Dual output drive system > < Three-phase and single-phase output currents >

26 7. Study of Significance Device Model and Reliability Evaluation for MVDC Distribution System Project leader Seok-Min Kim ( 김석민 ) B.S in Department of Electronic Engineering, Sejong University, Seoul, KOREA M.S in Department of Space Survey Information Technology, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Seung-Rae Jo ( 조승래 ) B.S in Department of Electrical and Computer Engineering, Mokpo National Maritime University, Mokpo, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Chan Hwangbo ( 황보찬 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of power converter for MVDC system - Design of simulation model and control algorithm for power converter - Development of a small-scaled power converter and selection of applied elements for actual verification Development of high reliability in power converter for MVDC system - Diagnose and tolerant techniques for IGBT failures of power converter 2. Research necessity Development of voltage source converter and control system for MVDC with economical competitiveness Optimal power converter design technology by trade-off analysis for selecting voltage-level Design of high reliable power converter by prediction of lifetime and failure management techniques < Concept of MVDC distribution > (a) 3-level NPC converter (b) Cascaded H-bridge converter < Trade-off analysis for optimal voltage level design > (c) Modular multi-level converter < Power converter topologies for MVDC system >

27 7. Study of Significance Device Model and Reliability Evaluation for MVDC Distribution System Project Contents 3. Research on high reliable power converter and efficient management techniques Low voltage ride through - Detection method of low voltage faults and grid angle - Independent control of active and reactive power under grid fault condition Submodule fault management - Detection of position and type of IGBT failure - Fault tolerant method considering capacitor voltage balancing of each submodule < Submodule failure in MMC > < Tolerant control for submodule fault in MMC > 4. Research on electrical isolation of MVDC converter valve Analysis of stray capacitance on converter valve - Between main components - Between wall and ceiling or floor Voltage balancing among converter valves - Modeling of equivalent circuit of converter valve - Development of voltage balancing technique among different converter valves considering stray capacitance ceiling wall floor d1, d2: Separation distance r1, r2: radius of corona shield s: distance between valve sections < Converter valve and stray capacitance > < Equivalent circuit of valves >

28 8. Survey of Motor-Inverter Control Algorithm Project leader Yeongsu Bak ( 박영수 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Young Seol Lim ( 임영설 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of propulsion system control algorithms based on a hydrogen fuel cell 2. Research and development contents Investigation and development of inverter and permanent magnet synchronous motor algorithms for propulsion system configuration - Investigation and analysis of permanent magnet synchronous motor control algorithms - Development of permanent magnet synchronous motor control algorithm for propulsion system depending on driving mode (acceleration - lane - deceleration) operation with simulation results Performance improvement of propulsion system based on energy management system of railway cars - Development of motor-inverter control algorithms for achieving high efficiency depending on driving mode - Comparison of performances (acceleration, torque characteristics, and efficiency) between existed and developed control algorithms by simulation results - Configuration of simulation model for energy management of railway cars when propulsion system is operated 3. Development results Permanent magnet synchronous motor drive control algorithms Simulation modeling implementation technology of propulsion control system depending on driving mode Comparison of propulsion system performances (output torque and efficiency) through simulation Construction of simulation model for energy management of railway cars 4. Research necessity Researches have been progressed to apply a propulsion system using a permanent magnet synchronous motor to railway cars, however, there are no domestic technologies for establishing and optimizing a stable control algorithms Application of permanent magnet synchronous motor for high-speed railway cars has been commercialized abroad and it is essential to develop and verify algorithms for optimum efficiency control and maximum torque control of permanent magnet synchronous motor taking advantages of high efficiency and output density In railway cars, it is necessary to develop an optimal inverter switching algorithm to prevent the effects of harmonics on the signal circuit generated by low switching frequency, harmonic resonance phenomena, and overcurrent to parallel capacitors Mechanical sensors such as encoders and resolvers, which are required to control permanent magnet synchronous motors, cause an increase in the price of the entire system and maintenance problems by environmental factors such as temperature, humidity, and vibration. Therefore, it is necessary to study the sensorless control algorithm

29 8. Survey of Motor-Inverter Control Algorithm 5. Coordinate system of IPMSM Three-phase coordinate system is represented by abc-axis and each axis has a phase difference of 120 degree Stationary reference frame is represented by α-β axis and synchronous reference frame is represented by d-q axis 6. Simulation circuit for IPMSM control of propulsion system depending on driving mode Power converter uses a 2-level inverter and it is composed of a DC voltage source, a DC capacitor, and six switching devices Load characteristics of railway car were simulated using a DLL block reflecting the mass and inertia of the railway car < Coordinate system of IPMSM > < Simulation circuit > 7. Simulation results of IPMSM control Before 1, IPMSM is operated by speed and current controller using proportional-integral controller If the IPMSM speed is faster than 1500 rpm as in 2, the IPMSM is controlled by the open-loop control method At 2, the PWM technique of the inverter is converted to synchronous PWM mode from asynchronous PWM mode If the voltage transfer ratio is higher than as in 3, the overmodulation is performed If the voltage transfer ratio is higher than as in 4, the 1-pulse control method is performed In the lane mode, operation of the inverter is stopped and the IPMSM maintains rotation state due to the inertia At 5, the inverter is operated and the driving mode is converted to deceleration mode from lane mode 8. Voltage limit ellipse and current limit circle using MATLAB simulation The current limit circle is expressed to a circle with maximum stator current as radius The voltage limit ellipse is expressed by using the parameters of the IPMSM and its size decreases with increasing speed of IPMSM < Simulation results of IPMSM control > < MATLAB simulation results >

30 9. Development of 3-Level Power Conversion System Control Algorithm for Energy Storage System Project leader Sungjoon Cho ( 조성준 ) Ph.D Candidate in Department of Electrical Engineering, Korea University, Seoul, KOREA He worked in Hyundai Heavy Industries co. ltd in power conversion department as a head researcher. Yoon Jang ( 장윤 ) B.S in Department of Electrical Engineering, Soonchunhyang University, Asan, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Sang-Hun Kim ( 김상훈 ) B.S in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Development of three-level power conversion system control algorithm for energy storage system - Design of controller interface specification (3-level PWM output) - Manufacture of prototype controller (3-level PWM output) - Development of 3-level PWM algorithm - Development of grid phase angle extraction algorithm - Development of bidirectional power control algorithm - Design of LC filter and element selection having a harmonic current reduction - Development of paralleled inverter operation 2. Research necessity The ESS (Energy Storage System) is a device that stores the generated electricity in a storage device such a battery, and then supplies power at a required time to achieve high power efficiency. It is possible to give the electric power supplier the function of improving electric quality such as load leveling, frequency regulator, buffering of renewable energy output. In addition, It can use basic charge and peak power reduction for electric power users, to use tariffs by time of day, and as an emergency power source. The PCS (Power Conversion System) for ESS is a core electronic component of the ESS that stores or supplies power to the load. It requires high efficiency and bidirectional power control. 3. System specification and configuration < Configuration of 3-level PCS for ESS > < Configuration of parallel 3-level PCS for ESS >

31 9. Development of 3-Level Power Conversion System Control Algorithm for Energy Storage System 4. Hardware configuration Control board and experiment set-up 15 kw small size PCS Master inverter Slave inverter Power stack < 3-level PCS control board > < 3-level PCS set-up > < Parallel inverter drive set-up > 5. Simulation results Simulation result of DSOGI-PLL method simulation Simulation result of parallel operation method of inverter < Simulation result of SRF-PLL > < Simulation result of DSOGI-PLL > < Operation of parallel inverter > 6. Experiment results Experiment result of current control for ESS battery discharging mode Experiment result of NPVB (Neutral Point Voltage Balancing) control for the unbalanced DC-link voltage < Simulation result of current control > < Simulation result of NPVB method >

32 10. Study of Environment Composition for Propulsion Power Converter Controller S/W Platform Project leader June-Hee Lee ( 이준희 ) B.S in Division of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Yoon Jang ( 장윤 ) B.S in Department of Electrical Engineering, Soonchunhyang University, Asan, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Sung-Soo Jeon ( 전상수 ) B.S in Division of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Project Contents 1. Research and development purpose Study of environment composition for propulsion power converter controller S/W platform - Development of S/W platform environment for high performance controller based on dual-core DSP (TMS320F28377) - The control cycle of the S/W platform is 300ms - All operations necessary for the propulsion system are performed within the control cycle - Check the basic operation and familiarize with each module in the controller based on the TMS320F S/W platform configuration through consultation with KRRI - Built in controller and S/W platform based on permanent magnet synchronous motor drive algorithm 2. Research necessity MCU (Micro Controller Units) have been around since the 1970s, and past MCUs have built-in memory, interrupt controllers, serial and parallel interfaces, counters, and timers, all of which have been limited capabilities. Recently, MCUs have been developed for convenient use in various control systems by incorporating high-performance I / O functions such as DMA controller, high-speed serial communication function, A / D converter, PWM output and PLL circuit. In recent years, the use of MCU has been increasing in the propulsion system of the transportation sector such as railroad, automobile, and ship. In the past, 16-bit single-core MCUs have been used, but recently, 32-bit multicore MCUs have been applied to various functions. Through the built of high-performance controller platform environment for propulsion system, overcome the complexity of circuit design, and advantageous in price competitiveness through single-core connection. 3. System specification and configuration < Comparison of C2000 series in TI > < Front and side view of propulsion converter controller >

33 10. Study of Environment Composition for Propulsion Power Converter Controller S/W Platform 4. Hardware configuration Circuit of MCU board and configuration of hardware < Circuit MCU board > < Configuration of hardware > 5. Experiment and test results Result of digital to analog conversion (DAC) and PWM signal test Result of eqep signal test Result of PWM output with duty ratio < Waveform of DAC test > < Waveform of PWM signal test > < Result of resolver circuit test > < Waveform of eqep signal test > < Waveform of PWM output (10%) test > < Waveform of PWM output (75%) test >

34 11. Investigation of 3-Level Hybrid ANPC Inverter Based on SiC MOSFET and Si IGBT Project leader Sungjoon Cho ( 조성준 ) Ph.D Candidate in Department of Electrical Engineering, Korea University, Seoul, KOREA He worked in Hyundai Heavy Industries co. ltd in power conversion department as a head researcher. Kyu-Chul Bae ( 배규철 ) B.S in Department of Cotrol Engineering, Kwangwoon University, Seoul, KOREA M.S in Department of Electricity and Electronic Engineering, Korea University, Seoul, KOREA Ph.D Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Dong Woo Seo ( 서동우 ) B.S in Department of Electronics and Radio Engineering, Kyung Hee University, Suwon, KOREA M.S Student in Department of Electrical and Computer Engineering, Ajou University, Suwon, KOREA Eui-Jae Lee ( 이의재 ) B.S Student in Department of Electrical Engineering, ChungBuk University, CheongJu, KOREA Project Contents 1. Research and development purpose Composition of Energy Storage System (ESS) - Development of ESS using 15kW three-level hybrid active neutral point clamped (ANPC) inverter - Loss analysis of hybrid ANPC inverter 2. Research necessity Existing ESS systems are composed of three-level NPC inverter as a power conversion system for supplying the power to energy storage device from the grid. The three-level NPC inverter has a temperature unbalance between the switches on each phase. Therefore, to overcome this drawback, the three-level active-npc (3L-ANPC) inverters are developed to improve the loss unbalance of NPC inverter. The 3L-ANPC is configured by adding a power switch instead of the clamping diode in NPC topology. These additional switches are used to select the current path of the neutral point and to distribute the losses evenly. < 3-level Hybrid ANPC topology >

35 11. Investigation of 3-Level Hybrid ANPC inverter based on SiC MOSFET and Si IGBT 3. Hardware configuration TMS320F28377 Test board < DSP control board PCB layout > < DSP control board configuration > 4. Control algorithms and switch loss analysis for Hybrid Active NPC Development of a switching modulation technique of three-level Hybrid ANPC inverter Development of a grid connecting algorithm Development of a DC link balancing algorithm Design of a LCL filter for grid connected inverter Development of a simulation for the actual capacity model DC-Link Switch AC Switch Neutral Point Switch < Hybrid ANPC switching patten > < Hybrid ANPC switch module > DC Link Voltage d q axis current Output current Switch loss[w] SiC + Si switch loss SW1 (Si) SW2 SW3 SW4 SW5 SW6 (SiC) (SiC) (Si) (Si) (Si) Conduction Loss Swithching Loss < DC link balancing control > < Hybrid ANPC switch loss >

36 Research Results International Journals 1. Yeongsu Bak, June-Seok Lee, and Kyo-Beum Lee, "Low-Voltage Ride-Though Control Strategy for a Grid- Connected Energy Storage System," Applied Science, vol. 8, no. 1, Jan SCI 2. Jin-Hyuk Park and Kyo-Beum Lee, "Performance Improvement for Reduction of Resonance in a Grid- Connected Inverter System Using an Improved DPWM Method," Energies, vol. 11, no. 1, Jan SCI 3. June-Seok Lee, Seung-Joo Lee, and Kyo-Beum Lee, "Novel Switching Method for Single-Phase NPC Three-Level Inverter with Neutral-Point Voltage Control," International Journal of Electronics, vol. 105, no. 2, pp , Feb SCI 4. Yongsoo Cho, Yeongsu Bak, and Kyo-Beum Lee, "Torque-Ripple Reduction and Fast Torque Response Strategy for Predictive Torque Control of Induction Motors," IEEE Transactions on Power Electronics, vol. 33, no. 3, pp , Mar SCI 5. Anatolii Tcai, Hye-Ung Shin, and Kyo-Beum Lee, "DC-Link Capacitor Current Ripple Reduction in DPWM based Back-to-Back Converters," IEEE Transactions on Industrial Electronics, vol. 65, no. 3, pp , Mar SCI 6. June-Hee Lee and Kyo-Beum Lee, "A Dead-Beat Control for Bridgeless Inverter Systems to Reduce the Distortion of Grid Current," IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 6, no. 1, pp , Mar SCIE 7. Yeongsu Bak and Kyo-Beum Lee, "Constant Speed Control of a Permanent Magnet Synchronous Motor Using a Reverse Matrix Converter under Variable Generator Input Conditions," IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 6, no. 1, pp , Mar SCIE 8. Jin-Hyuk Park, SongHee Yang, and Kyo-Beum Lee, "Synchronous Carrier-based Pulse Width Modulation Switching Method for a Vienna Rectifier," Journal of Power Electronics, vol. 18, no. 2, pp , Mar SCIE 9. Seok-Kyoon Kim and Kyo-Beum Lee, "Robust Offset-Free Speed Tracking Controller of Permanent Magnet Synchronous Generator for Wind Power Generation Applications," Electronics, Vol. 7, Iss. Apr SCIE 10. Yeongsu Bak and Kyo-Beum Lee, "Reverse Matrix Converter Control Method for PMSM Drives Using DPC," International Journal of Electronics, vol. 105, no. 5, pp , May SCI 11. Joon Young Park, Jiook Sin, Yeongsu Bak, Sung-Min Park, and Kyo-Beum Lee, "Common-mode Voltage Reduction for Inverters Connected in Parallel Using an MPC Method with Subdivided Voltage Vectors," Journal of Electrical Engineering and Technology, vol. 13, no. 3, pp , May SCIE 12. Han Rim Lee, Jin-Hyuk Park, and Kyo-Beum Lee, "Optimal Soft-Switching Scheme for a Bidirectional DC- DC Converters with Auxiliary Circuit," Journal of Power Electronics, vol. 18, no. 3, pp , May SCIE 13. Yong-Dae Kwon, Jin-Hyuk Park, and Kyo-Beum Lee, "Improving Line Current Distortion in Single-Phase Vienna Rectifiers Using Model-Based Predictive Control," Energies, vol. 11, no. 5, May SCIE 14. June-Seok Lee, Hyun-Woo Sim, Juyong Kim, and Kyo-Beum Lee, "Combination Analysis and Switching Method of a Cascaded H-Bridge Multilevel Inverter Based on Transformers with the Different Turns-Ratio for Increasing the Voltage Level," IEEE Transactions on Industrial Electronics, vol. 65, no. 6, pp , Jun SCI 15. Hyo-Chul In, Seok-Min Kim, and Kyo-Beum Lee, "Design and Control of Small DC-link Capacitor-Based Three-Level Inverter with Neutral-Point Voltage Balancing," Energies, vol. 11, no. 6, Jun SCIE 16. Seok-Kyoon Kim, June-Seok Lee, and Kyo-Beum Lee, "Robust Speed Control Algorithm with Disturbance Observer for Uncertain PMSM," International Journal of Electronics, vol. 105, no. 8, pp , Aug SCI 17. Ibrahim Alsofyani, Nik Rumzi Nik Idris, and Kyo-Beum Lee, "Dynamic Hysteresis Torque Band for Improving the Performance of Lookup-Table-Based DTC of Induction Machines," IEEE Transactions on Power Electronics, vol. 33, no. 9, pp , Sep SCI 18. Yeongsu Bak and Kyo-Beum Lee, "Reducing Switching Losses in Indirect Matrix Converter Drives : Discontinuous PWM Method," Journal of Power Electronics, vol. 18, no. 5, pp , Sep SCIE 19. Seok-Kyoon Kim, Jin-Hyuk Park, and Kyo-Beum Lee, "Robust optimal output voltage tracking algorithm for interleaved N-phase DC/DC boost converter with performance recovery property, International Journal of Electronics, vol. 105, no. 10, pp , Oct SCI 20. Anto Joseph, Thanga Raj Chelliah, Sze Sing Lee, and Kyo-Beum Lee, "Reliability of Variable Speed Pumped-Storage Plant, Electronics, vol. 7, no. 10, pp. 1-14, Oct SCIE

37 Research Results 21. June-Seok Lee, Raeho Kwak, and Kyo-Beum Lee, "Novel Discontinuous PWM Method for a Single-Phase Three-Level Neutral Point Clamped Inverter with Efficiency Improvement and Harmonic Reduction," IEEE Transactions on Power Electronics, vol. 33, no. 11, pp , Nov SCI 22. Seok-Min Kim, Ho-Sung Kang, and Kyo-Beum Lee, "Single-Phase Bidirectional On-Board Charger Using Starter Generator System in Hybrid Electric Vehicles," Electronics, vol. 7, no. 287, pp. 1-18, Nov SCIE 23. Anatolii Tcai, Ibrahim Mohd Alsofyani, In-Yong Seo, and Kyo-Beum Lee, "DC-link Ripple Reduction in a DPWM-Based Two-Level VSI," Energies, vol. 11, no. 11, pp. 1-15, Nov SCIE 24. Kiwoo Park and Kyo-Beum Lee, A Bidirectional Double Uneven Power Converter Based DC DC Converter for Solid-State Transformers, Electronics, vol. 7, no. 11, pp. 1-20, Nov SCIE 25. Seok-Kyoon Kim and Kyo-Beum Lee, "Robust DC-Link Voltage Tracking Controller with Variable Control Gain for Permanent Magnet Synchronous Generators," Electronics, vol. 7, no. 11, pp. 1-15, Nov SCIE 26. Seok-Min Kim, In Jung Won, Juyong Kim, and Kyo-Beum Lee, "DC-link Ripple Current Reduction Method for Three-level Inverters with Optimal Switching Pattern," IEEE Transactions on Industrial Electronics, vol. 65, no. 12, pp , Dec SCI 27. Jae-Goo Kim, Kyo-Beum Lee, and Jung-Wook Park, "Clamping-Angle Control PWM Method to Restore Linear Modulation Range of Voltage Source Inverter," IEEE Transactions on Power Electronics, vol. 33, no. 12, pp , Dec SCI 28. June-Hee Lee, June-Seok Lee, Hyun-Cheol Moon, and Kyo-Beum Lee, "An Improved Finite-Set Model Predictive Control Based on Discrete Space Vector Modulation for Grid-Connected Three-Level Voltage Source Inverter," IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 6, no. 4, pp , Dec SCIE 29. Hyun Cheol Moon, June-Seok Lee, and Kyo-Beum Lee, "A Robust Deadbeat Finite Set Model Predictive Current Control Based on Discrete Space Vector Modulation for Grid-Connected Voltage Source Inverter," IEEE Transactions on Energy Conversion, vol. 33, no. 4, pp , Dec SCI 30. Young-Seol Lim, June-Seok Lee, and Kyo-Beum Lee, "Advanced Speed Control for a Five-Leg Inverter Driving a Dual-Induction Motor System," IEEE Transactions on Industrial Electronics, vol. 66, no. 1, pp , Jan SCI 31. Seok-Min Kim, Min-Gyo Jeong, Juyong Kim, and Kyo-Beum Lee, "Hybrid Modulation Scheme for Switching Loss Reduction in a Modular Multilevel High-voltage Direct Current Converter," IEEE Transactions on Power Electronics, in press. SCI 32. Ibrahim Mohd Alsofyani, Nik Rumzi Nik Idris, and Kyo-Beum Lee, "Impact of Observability and Multi- Objective Optimization on the Performance of Extended Kalman Filter for DTC of AC Machines," Journal of Electrical Engineering & Technology, in press. SCIE 33. Hye-Ung Shin and Kyo-Beum Lee, "Fault Diagnosis Method for Switched Reluctance Machine Drive Systems using a Switching Signal," Journal of Electrical Engineering & Technology, in press. SCIE 34. Anto Joseph, Thanga Raj Chelliah, Raghu Selvaraj, and Kyo-Beum Lee, "Fault Diagnosis and Fault- Tolerant Control of Magawatt Power Electroni Converter-Fed Large Asynchronous Hydro-Generator," IEEE Journal of Emerging and Selected Topics in Power Electronics, in press. SCIE 35. Anto Joseph, Thanga Raj Chelliah, and Kyo-Beum Lee, "Multi-channel VSI fed large variable speed asynchronous hydro-condenser: fault analysis, fault diagnosis and fault tolerant control," IET Renewable Power Generation, in press. SCIE Domestic Journals 1. Keon Young Kim, Yeongsu Bak, and Kyo-Beum Lee " 극성판별이가능한최소제곱법기반의 IPMSM 회전자초기위치추정," 전력전자학회논문지, vol. 23, no. 1, pp , Feb Byeong-Gyu Kang, Shin-Myoung Jeong, Young-Seol Lim, June-Seok Lee, and Kyo-Beum Lee " 매입형영구자석동기전동기의넓은속도영역에서센서리스운전을위한전환알고리즘," 한국철도학회논문집, vol. 21, no. 5, pp , Jun Young Jae Lee, Yeongsu Bak, and Kyo-Beum Lee, EEMF 기반센서리스영구자석동기전동기구동시스템의구동재개방법, 전력전자학회논문지, 출판대기중.

38 Research Results International Conferences 1. Seok-Min Kim, June-Seok Lee, and Kyo-Beum Lee, "Fault-Tolerant Control Scheme for Modular Multilevel Converter based on Sorting Algorithm without Reserved Submodules," IEEE APEC Young-Seol Lim, June-Seok Lee, Joon Hyoung Ryu, and Kyo-Beum Lee, "Sensorless Control Using a Full- Order Observer Based on a Novel Flux Model of High Power Interior Permanent Magnet Synchronous Motor," IEEE APEC Dongho Choi, Yeongsu Bak, Jong-Pil Lee, Tae-Jin Kim, and Kyo-Beum Lee, "Control Strategy for Reduction of Current Distortion in Reverse Matrix Converter under Unbalanced Input Conditions," IEEE APEC Ibrahim Mohd Alsofyani, June-Hee Lee, Byung-Moon Han, and Kyo-Beum Lee, "Improved Performance of CFTC-based Direct Torque Control of Induction Machines by Increasing Torque Loop Bandwidth," IPEC Yun Jang, Yeongsu Bak, and Kyo-Beum Lee, "Indirect Matrix Converter for Permanent-Magnet- Synchronous-Motor Drives by Improved Torque Predictive Control," IPEC Keon Young Kim, Yeongsu Bak, Jin-Hyuk Park, and Kyo-Beum Lee, "Model Predictive Control Using Subdivided Voltage Vectors for Current Ripple Reduction in an Indirect Matrix Converter," IPEC Anatolii Tcai and Kyo-Beum Lee, "DC-link Ripple Current Reduction in Back-to-back converters with DPWM," IPEC Ibrahim Mohd Alsofyani,Byung-Moon Han, and Kyo-Beum Lee, Flux Regulation with Minimized Torque Ripple of DTC of Induction Machines at Low Speed by Controlling Single Hysteresis-Torque Band, ICEE Dongho Choi, Yeongsu Bak, and Kyo-Beum Lee, Short Fault Detection of Outer Switches in the Current Source Inverter for Reverse Matrix Converter, ICEE Seok-Min Kim and Kyo-Beum Lee, Control Method of Power Cycling Test Setup for Submodule Reliability Investigation of Modular Multilevel Converters, ICEE Dong-Woo Seo, June-Hee Lee, and Kyo-Beum Lee, Improved Model Predictive Control for Active NPC Grid-Connected Inverter System, ICEE Ho-Pyo Sohn, Seok-Min Kim, and Kyo-Beum Lee, Improving Input Current Quality and Dynamic Response for Diode Rectifier-Fed IPMSM Drive System using Small DC-link Capacitor, ICEE Young-Seol Lim, Kyo-Beum Lee, and June-Seok Lee, Wide-range Sensorless and MTPA Control Using a Full-order Flux Observer of High Power IPMSM for the Train Propulsion System, ICEE Yong-Dae Kwon, Jin-Hyuk Park, and Kyo-Beum Lee, Current Ripple Reduction Control for ZVS Operation of a Fuel-Cell System, IEEE ECCE Young-Seol Lim, June-Seok Lee, and Kyo-Beum Lee, Improved Model Predictive Control Method for Two Induction Motor Fed by Five-leg Inverter System, IEEE ECCE June-Seok Lee, and Kyo-Beum Lee, Open-Switch Fault Diagnosis and Tolerant Control Methods for a Vienna Rectifier using Bi-Directional Switches, IEEE ECCE Ibrahim Mohd Alsofyani, and Kyo-Beum Lee, Improved Overmodulation Strategy in DTC with Constant Frequency Torque Controller of PMSM for Quick Torque Control at Different Dynamic Conditions, IEEE ECCE Anatolii Tcai, Ibrahim Mohd Alsofyani, and Kyo-Beum Lee, DC-link Ripple Reduction in a DPWM-based Two Level VSC", IEEE ECCE Seok-Min Kim and Kyo-Beum Lee, Design and Control Method of a Solid-State Transformer for MVDC Applications, IEEE PEAC2018. Domestic Conferences 1. Young-Seol Lim, June-Seok Lee, and Kyo-Beum Lee, 5- 레그인버터를위한새로운모델예측제어기법, 2018 전력전자학회하계학술대회, Ho-Sung Kang, Seok-Min Kim, Donghwi Lim, Raeho Kwak, Kyo-Min Kim, and Kyo-Beum Lee, 시동발전기시스템을이용한탑재형충전기의설계및제어방법, 2018 전력전자학회하계학술대회, Sea-Won Kim, Dong-Woo Seo, and Kyo-Beum Lee, 표면부착형영구자석동기전동기의회전자자속관측기를이용한모델기반센서리스제어기법분석, 2018 대한전기학회전기기기및에너지변환시스템부문회추계학술대회논문집, pp , 2018.

39 Research Results 4. Young-Deak Kim, Dong-Woo Seo, and Kyo-Beum Lee, IPMSM 의추정된동기좌표계 d 축에고주파전압주입을이용한센서리스제어기법, 2018 대한전기학회전기기기및에너지변환시스템부문회추계학술대회논문집, pp , Sang-Sin Han, Dong-Woo Seo, and Kyo-Beum Lee, 고주파전압을인가한매입형영구자석동기전동기의초기고정자전류응답, 2018 대한전기학회전기기기및에너지변환시스템부문회추계학술대회논문집, pp , Geum-Bok Mun, Dong-Woo Seo, and Kyo-Beum Lee, 매입형영구자석동기전동기의단위전류당최대토크제어기법, 2018 대한전기학회전기기기및에너지변환시스템부문회추계학술대회논문집, pp , Seung-Rae Jo, Seok-Min Kim, and Kyo-Beum Lee, 특고압직류배전망을위한모듈형멀티레벨컨버터의계통사고 ride-through 기술, 2018 전력전자학회추계학술대회, Young Jae Lee, Dong-Woo Seo, Yeongsu Bak, and Kyo-Beum Lee, 영구자석동기전동기센서리스구동시스템의구동재개방법, 2018 전력전자학회추계학술대회, Ki-Hoon Kwon and Kyo-Beum Lee, 최소자승법을이용한영구자석동기전동기의파라미터추정, 2018 전력전자학회추계학술대회, Seong-Won Kim, Dong-Woo Seo, and Kyo-Beum Lee, Active NPC 인버터를적용한계통연계전력변환시스템의제어, 2018 전력전자학회추계학술대회, Heung-Seok Park and Kyo-Beum Lee, Active NPC 인버터의모델링및성능분석, 2018 전력전자학회추계학술대회, Award 1. Ajou Publication Award (Silver and Blonze, May. 2018) 2. So Choon Award, KIPE (Korea Institute of Power Electronics, Jul. 2018) 3. The best paper award, Ho-Sung Kang, Seok-Min Kim, Donghwi Lim, Raeho Kwak, Kyo-Min Kim, and Kyo- Beum Lee, Design and Control Method of an On-Board Charger using a Hybrid Starter Generator System in Hybrid Electric Vehicles, KIPE Annual Conference 2018 (Jul. 2018) 4. Best Reviewer Award, JEET (Journal of Electrical Engineering and Technology, Nov. 2018) 5. Best Associate Editor Award, JEET (Journal of Electrical Engineering and Technology, Nov. 2018) 6. Excel Award, JEET (Journal of Electrical Engineering and Technology, Nov. 2018) 7. The best presentation award, Seok-Min Kim and Kyo-Beum Lee, Design and Control Method of a Solid- State Transformer for MVDC Applications, IEEE PEAC (Nov. 2018) 8. The best paper award, Young Jae Lee, Dong-Woo Seo, Yeongsu Bak, and Kyo-Beum Lee, Restarting Method for PMSM Sensorless Drive Systems, KIPE General Meeting and Autumn Conference 2018 (Nov. 2018) Patent Registration 1. 이중병렬전동기의구동장치 (driving Device for Dual Parallel Motors), Korean Patent , Aug. 10, Patent Pending 1. 소용량인터리브드준공진플라이백컨버터, 이의밸리스위칭방법및이를포함하는태양광전력변환장치 (Small Power Interleaved Quasi-Resonant Flyback Converter, Valley Switching Method Mererof and Photovoltaic Power Conversion Apparatus Including the Same), Korean Patent , Sep. 19, 센서리스제어가적용된발전시스템의구동재개장치및방법 (Apparatus and Method for Drive Restarting of Power Generation System Applied Sensorless), Korean Patent , Dec. 04, 토크예측제어를통한 PMSM 구동제어장치및방법 (Apparatus and Method for PMSM Drive Control Using Torque Predictive Control), Korean Patent , Dec. 10, 모델예측제어를통한전력변환시스템의구동제어장치및방법 (Apparatus and Method for Driving Control of Power Conversion System Based on Model Predictive Control), Korean Patent , Dec. 24, 2018.

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