A Study on The Control Technique for Modular Three-Phase Uninterruptible Power Supply(UPS) With Boost Converter -Author Jin, Seongmin Dept. of Electrical Engineering Incheon National University-승압기능을 갖는 모듈형 3상 무정전 전원장치(UPS)의 제어기법에 관한 연구

A Study on The Control Technique for Modular
Three-Phase Uninterruptible Power Supply(UPS)
With Boost Converter

승압기능을 갖는 모듈형 3상 무정전
전원장치(UPS)의 제어기법에 관한 연구
Jin, Seongmin
Dept. of Electrical Engineering
Incheon National University

ABSTRACT
This study proposes a control algorithm design and implementation method for the control method of the modular three phase uninterruptible power supply (UPS) with boost function. With the development of the industrial age, there has been an increase in the load required to maintain the constant power source, which has increased the demand for the uninterruptible power supply. In addition, a parallel type uninterruptible power supply unit of a modular type is widely used to satisfy a load of a high capacity It is difficult to apply a desired output voltage to a load by using a 250V DC voltage as the input power source of a UPS used in a power plant system. Therefore, it is necessary to design a module suitable for UPS system for power plant. A UPS for applying 3-phase AC voltage to a load is generally composed of a 3-phase inverter and an output L-C filter.  In order to apply this to the power plant system, it is necessary to construct and control a power converter for a single module that boosts the input voltage by applying a boost converter to the input of the inverter to supply the constant voltage to the inverter. In addition, a parallel operation control technique is necessary to solve the problem of connecting such a single module in parallel. Therefore, in this study, the study on the configuration, design and parallel operation control technique for single module UPS for power plant was conducted. The proposed algorithm proved its superior performance and feasibility through simulation and experimental results
 Keywords: Uninterruptible power supply, single module power converter for plant, parallel operation control
LINK
https://www.mediafire.com/file/dk35mnbwdaus32x/A_Study_on_The_Control_Technique_for_Modular__three-phase_UPS.pdf/file

A Study on High Efficiency Technology for Charging of Electric Vehicle -Author Jin-Hak Kim Department of Electronic and Electrical Engineering Graduate School

A Study on High Efficiency Technology for Charging of Electric Vehicle 
Author:Jin-Hak Kim 
Department of Electronic and Electrical Engineering Graduate School Keimyung University (Supervised by Professor Jun-Ho Kim) 

ABSTRACT
 As environmental pollution intensifies, government regulations and eco-friendly policies are being strengthened to solve these problems. In the automobile market, research on electric vehicles, which are environmentally friendly automobiles, is becoming active. For the development of electric vehicles, it is essential to build charging infrastructure and develop charging technology for competitive prices. Therefore, in this paper, presents a technology for high efficiency of electric car rapid charger. The conventional rapid charger for electric vehicle, three 20kW AC-DC converters are arranged in parallel, and each 20kW module is composed of one PFC(Power Factor Corrector) and DC-DC converter. Since DC-DC converter directly charges the battery, the efficiency of the DC-DC converter greatly affects the overall fast charger efficiency. Therefore, it is very important to select a DC-DC converter topology suitable for high efficiency and to design an optimum for high-efficiency rapid charger development. The conventional DC-DC converter topologies for electric vehicle rapid chargers have used LLC resonant converters or phase-shift full-bridge converters. Both converters have a fatal disadvantage that can be difficult to achieve with high efficiency and miniaturization in battery charger applications. Therefore, in this paper, we propose a new LLC-Buck DC-DC converter for a rapid charger that can overcome the existing disadvantages. The proposed converter is designed as frequency fixed type at the resonance point by separating the insulation function and the charging function. The buck converter, which is a structure without circulating current, is connected in series. The proposed converter has the following advantages. 1. The switching frequency is fixed to the resonant frequency so that LLC resonant converter operates at the highest efficiency point. Then, ZVS and ZCS are achieved even if the load fluctuates, and the circulating current is minimized. 2. Based on the ZVS and ZCS achievement, a small scale transformer was designed to allow a high frequency operation to be achieved. 3. By using two transformers, it is possible to design more optimally in terms of size than one high-capacity transformer. 4. The series connection of the secondary rectifiers lowered the internal voltage of the secondary rectifiers, reducing costs and losses. These four advantages, it possible to charge the battery with high efficiency throughout the battery charge period, and the efficiency fluctuation is minimized. And high power density can be achieved. As a result of the fabrication and testing of the proposed converter, it was confirmed that the battery is always charged at a high efficiency of 97% in the entire load range. This is more than 1% higher efficiency than conventional frequency-variable converters. As a result of applying the proposed converter to the rapid charger, the high efficiency of 95.242% of the total efficiency was achieved through the high efficiency of the DC-DC converter. Also confirmed that it is competitive in terms of volume through comparison with other companies products. Therefore, the proposed LLC-Buck DC-DC converter is expected to be widely used in electric car chargers requiring high efficiency and small scale.
FULL TEXT LINK
https://www.mediafire.com/file/zlllfzxnxjwwddf/A_Study_on_High_Efficiency_Technology_for_Charging_of_Electric_Vehicle.pdf/file

A Study on Design of High Efficiency LEV Battery Charger for Low Voltage Battery Pack and Adaptive Charge Algorithm -Author Dongrak Kim Department of Electrical and Computer Engineering The Graduate School Sungkyunkwan University

A Study on Design of High Efficiency LEV Battery Charger for Low Voltage Battery Pack and Adaptive Charge Algorithm

Author: Dongrak Kim

 Department of Electrical and Computer Engineering The Graduate School Sungkyunkwan University

 Abstract
 In recent years, lithium-ion batteries have been widely used in automobiles, golf carts, electric bicycles, energy storage devices (ESS), etc., and are rapidly replacing lead-acid batteries. Lithium-ion batteries are attracting attention owing to their high input/output power, long cycle life, and high energy density compared with lead-acid batteries. Lithium-ion batteries used in electric car battery packs require high energy densities of over 200 Wh / kg, charging speeds of over 1C, and lifespans of more than 1000 cycles. To satisfy these conditions, the costs of battery material and manufacturing are increased. Attempts have been made to develop a battery pack using the 18650 type cylindrical lithium ion battery (LIB), which is cost competitive but lacks the above-mentioned input/output power and lifetime characteristics in the light electric vehicle (LEV) system market. Moreover, the charging time and lifetime characteristics of the 18650 battery type currently used are not sufficient to meet the LEV customers' demand of one-hour charge time and a lifetime of more than 1000 cycles. Therefore, this paper proposes a rapid charging solution for the 18650 type LIB pack used in an electric forklift. The proposed rapid charge solution offers three benefits: shortened charge time, extended battery cycle life and improved charging efficiency. To achieve these benefits, a new - ２ - DC / DC converter topology and fast charge algorithm have been proposed. First, a PWM DC / DC converter using primary resonance tank (PRT) was proposed to increase the efficiency of the rapid charger. The converter's structure is similar to that of the conventional resonant converter but uses PWM control to eliminate problems caused by frequency variations. The top switch can operate with zero voltage switching (ZVS) and other switching elements including the bottom switch and output rectifier can be operated with ZVS and zero current switching (ZCS) by using a proper design of the resonant tank. The converter uses the PRT to prevent soft switching operations from being disturbed by resonance. Several design procedures are proposed as the design of PWM PRT converters is related to various parameters such as the resonant tank, transformer turns ratio, magnetizing inductance, and duty ratio. Secondly, we analyzed the causes of various deteriorations caused by the charging of the lithium battery; this was required for the rapid charging algorithm development. Among these, the lithium plating conditions having the highest deterioration rate during fast charging were studied. The proposed rapid charge algorithm was developed using an electrochemical model, which predicts the maximum charge current limit according to the cell voltage, current, and temperature and a differential voltage analysis (DVA), which is a tool to detect battery characteristics. The proposed adaptive fast charge algorithm detects the battery degradation state through charging/discharging patterns, and is optimized and controlled in real time reflecting the characteristics of the battery module and pack degradation as the charging/discharging cycles increase. The proposed charger and the charging algorithm are verified with a 5 kWh class battery pack consisting of 18650 type cylindrical cells and the results are presented.
Index Terms—Pulse-Width Modulation, Zero Voltage Switching, Fast Charging, Adaptive Charging Algorithm, Differential Voltage Analysis
FULL TEXT LINK
https://www.mediafire.com/file/l6g7e1vbphz6jgk/A_Study_on_Design_of_High_Efficiency_LEV_Battery_Charger_for_Low_Voltage_Battery_Pack.pdf/file

NOBREAK DUPLA CONVERSÃO MONOFÁSICO ISOLADO EM ALTA FREQUÊNCIA COM TENSÃO DE ENTRADA BIVOLT E POTÊNCIA DE 1 kVA, BASEADO NO CONCEITO DE CIRCUITO MULTI-PORTAS-MÁRIO FRANCISCO APOLINÁRIO-Dissertação (mestrado) – Universidade Federal do Ceará, Centro de Tecnologia, Programa de Pós- Graduação em Engenharia Elétrica

NOBREAK DUPLA CONVERSÃO MONOFÁSICO ISOLADO EM ALTA FREQUÊNCIA
COM TENSÃO DE ENTRADA BIVOLT E POTÊNCIA DE 1 kVA, BASEADO NO
CONCEITO DE CIRCUITO MULTI-PORTAS

AUTOR:MÁRIO FRANCISCO APOLINÁRIO

Dissertação apresentada ao Programa de Pós- Graduação em Engenharia Elétrica da Universidade Federal do Ceará, como parte do requisito parcial para obtenção do título de Mestre em Engenharia Elétrica. Área de Concentração: Sistemas de Energia Elétrica. Linha de pesquisa: Eletrônica de Potência

RESUMO
 Este trabalho apresenta o projeto de um sistema ininterrupto de energia (nobreak) dupla conversão monofásico com tensão na entrada alternada bivolt, tensão na saída alternada de 110V, tensão no banco de baterias de 24V, e potência aparente na saída de 1kVA. A topologia do nobreak proposta está baseada no conceito de circuito multi-portas, a qual faz uso de um transformador isolador de alta frequência que permite a interconexão entre diferentes fontes de energia. O referido circuito multi-portas apresenta duas portas de entrada, e duas portas de saída dedicadas a alimentar o inversor de tensão em ponte-completa, e o carregador de baterias derivado da topologia Buck. A rede elétrica é conectada à porta de entrada através de um conversor ponte-completa, e o banco de baterias é conectado a outra porta de entrada através de um conversor Push-Pull alimentado em tensão. Algumas particularidades do sistema proposto são indicadas: dois estágios de conversão para cada modo de operação, e a forma de onda de tensão quadrada com três níveis na saída do inversor. Observa-se também a praticidade na forma como diferentes fontes de energia podem ser interligadas ao nobreak proposto, que até então é dificilmente visto em outros trabalhos. Um protótipo do nobreak proposto foi montado, sendo obtido uma eficiência superior a 80% em modo rede para 1kVA, e uma eficiência de 74% em modo bateria para 860VA. Sendo assim, o sistema ininterrupto proposto é considerado uma alternativa às aplicações com potência menor ou igual a 2kVA.

Palavras-Chave: Nobreak Dupla Conversão. Circuito Multi-Portas. Transformador Isolador de Alta Frequência.

LINK FONTE ORIGINAL:
http://www.repositorio.ufc.br/bitstream/riufc/23481/3/2017_dis_mfapolinário.pdf