Operation Analysis of Bipolar Low-Voltage DC distribution system based on Distributed Generation

Hardware   configuration .Dual Buck voltage Balancer

Operation Analysis of Bipolar Low-Voltage DC distribution system based on Distributed Generation Han, Tae Hee
Department of Electrical Engineering Graduate School, Myongji University
 Supervised by Prof. Byung Moon Han
The DC distribution has higher efficiency than the AC distribution because it easily controls the power flow in the distributed generators, DC load, and battery storage using single power conversion. However, the DC distribution is not easy to block the fault current and it does not have specific standards compared with the AC distribution, which should be prepared through a lot of technical efforts. The DC distribution is divided into unipolar type and bipolar type. The unipolar type has a positive terminal and a negative terminal, while the bipolar type has a positive terminal, a negative terminal, and the ground terminal. Although the structure of unipolar type is simple, the reliability against fault is rather low. On the other hand, the bipolar type has higher transmission capacity and lower rated voltage of the converter, which secures the cost effectiveness. Also it is possible to form a neutral point with advantages of high reliability and stability. In this thesis, many problems that can occur from the operation of bipolar DC distribution in connection with the AC/DC interconnection operation were analyzed. The energy management method for the AC/DC power trade and the operational principle of distributed generator and energy storage were analyzed. In order to analyze the operation and performance of unipolar distribution system, a 3kW-class hardware simulator was built, which is composed of the grid-tied three-level inverter, battery storage, super capacitors, and the voltage balancer. Also the various analysis results through experiments with hardware simulator were described by a variety tests of produces hardware are described.
THESIS LINK
http://www.mediafire.com/view/iyq0ziqvjxq269y/Operation_Analysis_of_Bipolar_Low-Voltage_DC_distribution_system_based_on_Distributed_Generation-2014.pdf

Analysis of PWM Inverter Characteristics for High-Speed Train Drive System

Analysis of PWM Inverter Characteristics for High-Speed Train Drive System
AUTHOR SOON HWAN KWON
MAJOR IN ELECTRICAL ENERGY AND NEW TECHNOLOGY ENG.
DEPT. OF ELECTRONICS AND ELECTRIC ENG.
THE GRADUATE SCHOOL CHUNG-ANG UNIVERSITY

( Abstract )
Interior permanent magnet synchronous motor is in the limelight as traction motor because it has advantages of miniaturization, reducing weight, and saving on maintenance costs. Because high-speed trains are large capacity loads, it is necessary to establish the design and development of inverter topology for driving IPMSM. NPC 3-level inverter has a high voltage rating and low harmonic, and can implement large capacity power conversion system. Also, it is easy to miniaturize and reduce weight because it does not need additional capacitors in comparison with other multilevel inverter topology. In this study, speed control of the IPMSM drives for the next generation domestic high-speed train system using 2-level inverter and NPC 3-level inverter is presented. Simulators of the system are implemented and simulations are performed. Finally, the designed systems are verified by comparison between simulations and experiments.
LINK THESIS
https://www.mediafire.com/?mopph11g5iju1bj

A PWM control strategy for low-speed operation of three-level NPC inverter Department of Electrical and Computer Engineering Graduate School, Pusan National University

 

A PWM control strategy for low-speed operation of three-level NPC inverter based on bootstrap gate drive circuit
Jun-Hyung Jung
Department of Electrical and Computer Engineering Graduate School, Pusan National University Abstract
This paper proposes the pulse with modulation (PWM) control strategy for low- speed operation in the three-level neutral-point-clamped (NPC)inverters based onthe bootstrap gate drive circuit
FULL THESIS
https://www.mediafire.com/?4qfn7i7ell3f8uf

Back-to-Back NPC Switching Technique to Reduce Power Loss of Back-to-Back NPC System for Offshore Wind Farm 2013

Switching Technique to Reduce Power Loss of Back-to-Back NPC System for Off shore Wind Farm HongSeok-Jin
Mechatronics Engineering Cooperation Course Sungkyunkwan University
ABSTRACT
 In this paper,3-LevelNPC is applied as Back-to-Back foroffshore wind farm topology using PMSG.In caseofapplying 3-LevelNPC,each switch can withstand higher voltage than existing 2-Levelinverter,but overallloss of power converters is dramatically increased because amount of switching elemenT is increased.Thus,new switching method issuggested for 3-LevelNPC VSC If suggested method is applied,loss in NPC is minimized.
FULL THESIS
https://www.mediafire.com/?9fyma5k7jvdg4gl

ZVT Resonant Boost Converter with New Auxiliary Circuit Kim Mo Se Dept. of Mechatronics Engineering Sungkyunkwan University 2013

ABSTRACT
Switch mode power supplies have become smaller and lighter due to higher switching frequency. However, higher switching frequency causes lots of periodic losses at switch turn-ON and turn-OFF,resulting in increasing losses of the whole system.Therefore,many converters have been presented that use resonance circuit to reduces witching losses. In this paper,A new zero voltage transition resonant boost converter is proposed.The conventional boost converter generates switching losses at turn ON and OFF,and this causesa reduction in the whole system’sefficiency.The proposed ZVT resonant boost converter utilizes a  method using an auxiliary circuit with a resonant inductor,capacitor and two auxiliary switch. Therefore the proposed zero voltage transition n resonant boost converter reduces switching losses more than the conventional hard switching converter. Also,the experimentis conducted with the 4[kW],30[kHz]converter which steps up the voltage from 200[V]to 400[V].It is confirmed that the result of the experimentand that of the simulation are same,and the validity of the converter is verified.
FULL THESIS
https://www.mediafire.com/?m14iamz6pzj6kj7