• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 전력전자학술대회 논문집
• /
• pp.399-400
• /
• 2012

The proposed battery charger presented in this paper is suitable for Lead-Acid Battery and the dc/dc buck converter topology is applied as a charger circuit. The technique adopted in this charger is constant current & constant voltage dual mode, which is decided by the value of voltage of proposed battery. Automatic mode change function is detected by the percentage value of level of battery charging. CC Mode (Constant Current Mode) is operated when charging level is below 80% of the total charging of Battery voltage and above 80% of battery voltage charging, CV Mode (Constant Voltage Mode) is automatically operated. As the charging level exceeds 120%, it automatically terminates charging. The feedback signal to the PWM generator for charging the battery is controlled by using the current and voltage measurement circuits simultaneously. This technique will degrade the damage of proposed type of battery and improve the power efficiency of charger. Finally, a prototype charger circuit designed for a 12-V 7-Ah lead acid battery is constructed and tested to confirm the theoretical predictions. Satisfactory performance is obtained from simulation and the experimental results.

• Journal of Power Electronics
• /
• 제15권4호
• /
• pp.1026-1034
• /
• 2015

In this paper, a unified control strategy using the current space vector modulation (CSVM) technique is proposed and applied to a bidirectional three-phase DC/AC converter. The operation of the converter changes with the direction of the power flow. In the charging mode, it works as a buck type rectifier; and during the discharging mode, it operates as a boost type inverter, which makes it suitable as an interface between high voltage AC grids and low voltage energy storage devices. This topology has the following advantages: high conversion efficiency, high power factor at the grid side, tight control of the charging current and fast transition between the charging and discharging modes. The operating principle of the mode analysis, the gate signal generation, the general control strategy and the transition from a constant current (CC) to a constant voltage (CV) in the charging mode are discussed. The proposed control strategy has been validated by simulations and experimental results obtained with a 1kW laboratory prototype using supercapacitors as an energy storage device.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2013년도 추계학술대회 논문집
• /
• pp.13-14
• /
• 2013

Multiple output converters (MOCs) are widely used for applications which require various kinds of the output voltages due to its advantages in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, a novel Time Division Multiple Control (TDMC) method to regulate all the outputs in high precision is proposed and applied to the double ended forward converter for the multiple battery charger. Additional benefit of the proposed topology is to require only one secondary winding in the transformer for all the outputs. The proposed converter can charge two different kinds of batteries or same kind of batteries in different state of charges (SOCs) by CC/CV mode independently with the even degree of tight regulation, thereby satisfying the ripple requirements for each battery.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
• /
• pp.82-86
• /
• 2004

In this paper, a cycler system for the Lithium-Polymer battery with the large capacity of 120Ah is presented. This system is constituted as the two units for the charging and discharging. The Lithium-Polymer battery should be charged in CC and CV mode, and it is required a very high precision control of the voltage and current for the charging unit. To decrease the switching noises and harmonics, parallel operation method is adopted and utilized in the power conversion module. The discharging unit has a link AC system function to return the discharging energy of battery to AC line and has comparatively less thermal loss. These units are designed to be controlled and monitored by personal computer. The total system for the battery charging and discharging is described and presented.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2016년도 전력전자학술대회 논문집
• /
• pp.323-324
• /
• 2016

In this paper a high efficiency bidirectional resonant converterfor Vehicle-to-Grid applications (V2G) is proposed.The proposed converter has adopted an LC auxiliary circuit in the third winding of the transformer. With the proposed method full softswitching can be ensured in all switches over a wide range of loadsand the secondary ringing can be removed with no additional snubber or clamp circuitry.In addition, since the proposed resonant converter is able to operate at an almost constant resonant frequencyregardless of the load, CC/CV charge of the battery can be simply implemented with high efficiency. A 3.3 kW bidirectional converter for On-Board Charger of Electric Vehicle is implemented to verify the validity of the proposed method. The experimental results show the high efficiency characteristics of the proposed converter over the wide range of load in both charge and discharge mode. The maximum efficiency of the proposed system was 98.13 % at 2.3 kW during the constant voltage mode charge operation.

• 전력전자학회논문지
• /
• 제22권2호
• /
• pp.126-133
• /
• 2017

The conventional battery charger requires two separate voltage and current compensators to achieve constant current and constant-current-charging profile. This compensator configuration leads to an inevitable transient response during the mode change between the constant current and the constant voltage operation. Futhermore, a tedious and complicated design process is required to consider a widely changing battery voltage and the nonlinear electrical properties of Li-ion battery. This study proposes a single integrated voltage-current compensator of the LLC resonant converter for Li-ion battery charger applications to overcome the aforementioned drawbacks. The proposed compensator is designed to provide a smooth and reliable performance during the entire charging process while providing the reduced design efforts and seamless mode transient response. Several experimental results based on a 300 W prototype converter and its theoretical analysis are provided to verify the effectiveness of the proposed compensator.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2014년도 전력전자학술대회 논문집
• /
• pp.191-192
• /
• 2014

Multiple output converters (MOCs) are widely used for applications which require various levels of the output voltages due to their benefits in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, a novel Time Division Multiple Control (TDMC) method to regulate all the outputs in high precision is proposed and applied for the multiple output battery charger based on the phase shift full bridge topology to charge a multiple number of batteries at one time. The proposed converter can charge three different kinds of batteries or same kind of batteries in different state of charges (SOCs) by using constant current/constant voltage (CC/CV) charge mode independently. At the same time it can provide an even degree of tight regulation for each output to satisfy the strict ripple requirement of the battery. The validity and feasibility of the proposed method are verified through the experiments.

• 한국위성정보통신학회논문지
• /
• 제11권3호
• /
• pp.24-27
• /
• 2016

본 연구에서는 연료전지 중 발전효율이 50% 이상으로 가장 높고 가정용(1~10kW급) 시스템으로 필요성이 높아지고 있는 고체산화물 연료전지(SOFC, Solid Oxide Fuel Cell)에 대한 평가시스템을 설계하여 최적의 평가성능을 구현코자 하였다. 최적의 연료전지 평가시스템을 구현하기 위하여 전처리 및 반응조건 제어를 위한 온도제어모듈, 반응물에 대한 유량제어모듈, 전자부하기 등을 구현하였다. 온도제어모듈은 K형 서머커플을 사용하여 운전온도인 $750^{\circ}C$에서 $1^{\circ}C$이내의 정밀도 구현이 가능토록 설계하였고, 가스의 양이 일정하게 유지하기 위한 가습기 구조를 설계하였으며, 송풍기 및 히터의 정밀제어가 가능하도록 위상제어보드를 설계하여 적용함으로서 목표성능을 구현하였으며, 전자부하기는 방전방식으로 정전압, 정전류, 정저항 모드와 아날로그 입력과 출력모듈에 별도의 DC-DC 컨버터를 사용하여 오류를 최소화하였다. 구현한 평가시스템의 성능을 측정한 결과 스택전압은 80V에서 0.15%, 스택전류는 100A에서 0.1%의 정밀제어가 가능함을 확인하였다.