• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.433-437
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• 1998

Equalize SOC of the cell which effect on the charge.discharge ability and the efficiency of the battery, through the charge.discharge characteristic test of the battery source, and develope the high efficiency charge.discharge system in the series HEV have a constant engine-generator output. For this, in this paper, establish the electrical model and the condition of high efficiency charge.discharge, and proposed the improvement method of charge.discharge characteristic in the battery source that consist of twenty Ni-MH cells connected serial/parallel

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.144-148
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• 2023

Aircraft battery is the core equipment of an aircraft that supplies engine starting power and emergency power, and it must be charged to ensure sufficient capacity at all times and maintain high reliability to ensure stable power supply. The battery of the T-50 series aircraft is designed to enable the engine to start up to two times in temperatures as low as -18℃ and above. However, intermittent failures in engine starting have been observed during winter. In this paper, we analyze the failure phenomena occurring during low-temperature charging of the battery and improve the charging algorithm based on the analysis and test. Additionally, the results of start simulation tests show that the battery charging defects at low temperatures are resolved, and an improvement in the charging performance is confirmed; thus, validating the effectiveness of the new algorithm.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.309-317
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• 2005

It is expected that fully-implantable middle-ear hearing devices (FIMEHDs) will soon be available with the advantages of complete concealment, easy surgical implantation, and low power operation to resolve the problems of semi-implantable middle-ear hearing devices (SIMEHDs) such as discomfort of wearing an external device and replacement of battery. Over the last 3 years, a Korean research team at Kyungpook National University has developed an FIMEHD called ACRHS-1 based on a differential floating mass transducer (DFMT). The main research focus was functional improvement, the establishment of easy surgical procedures for implantation, miniaturization, and a low-power operation. Accordingly, this paper reviews the overall system architecture, functions, and experimental results for ACRHS-1 and its related accessories, including a wireless battery charger and remote controller.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.860-868
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• 2016

A bidirectional DC-DC converter (BDC) is an indispensable electrical unit for the electric vehicles (EVs). High efficiency, high power density, isolation, light weight and reliability are all essential requirements for BDC. In this paper, a 3 kW BDC for the battery charger of EVs is proposed. The proposed converter consists of a half-bridge structure on the primary side and an isolation transformer and a synchronous rectifier structure on the secondary side. With this topology, minimum number of switching devices are required for bidirectional power flow between the two dc buses of EVs. The easy implementation of the synchronous rectification gives advantages in terms of efficiency, cost and flexibility. The proposed BDC achieves high efficiency when operating in both modes (step-up and step-down). A 3 kW prototype is implemented to verify theoretical analysis and the performance of the proposed converter.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.13-14
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• 2016

This paper has introduces a novel Integrated On-board Charger (IOBC) to reduce the size, weight and cost of power conversion stages in Electric Vehicles (EVs). The IOBC is composed of an OBC and a low voltage dc-dc converter (LDC). The IOBC includes a bidirectional ac-dc converter and a bidirectional full-bridge converter with an active clamp circuit. The LDC converter is a hybrid topology combining an active clamped full-bridge converter and a forward converter derived from the Weinburg converter topology. Unlike conventional OBC, the proposed IOBC is compact and the LDC converter of it can achieve a higher efficiency. In addition, the LDC converter of the proposed IOBC can achieve high step-down voltage conversion ratio, no circulating current, no reverse recovery current of the rectifier diodes and small ripple current of output inductor on the auxiliary battery. A 1kW hardware of the LDC converter is implemented to verify the performances of the proposed IOBC.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.250-251
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• 2012

This paper proposes a new secondary battery charger/discharger available for zero voltage discharge which is used for test equipments and formation. The proposed system is able to discharge the battery to zero voltage which does not matter to voltage drop of circuit. The validity of proposed system is verified by experiment.

• Journal of Power Electronics
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• v.12 no.3
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• pp.487-494
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• 2012

A new low cost high power density photovoltaic power conditioning system (PV PCS) with an energy storage system is proposed in this paper. Its high power density and cost effectiveness can be achieved through the unification of the maximum power point tracker and the battery charger/discharger. Despite the reduced power stage, the proposed system can achieve the same performance in terms of maximum power point tracking and battery charging/discharging as the conventional system. When a utility power failure happens, the proposed system cannot perform maximum power point tracking at the UPS mode. However, the predetermined battery voltage near the maximum power point of the PV array can effectively generate a reasonable PV power even at the UPS mode. Therefore, it features a simpler structure, less mass, lower cost, and fewer devices. Finally, to confirm the operation, validity, and features of the proposed system, a theoretical analysis and experimental results from a single phase AC 220Vrms/1.5kW prototype are presented.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.191-192
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• 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.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.491-499
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• 2021

Batteries are widely used for energy storage, such as ESS(Energy Storage System), electric vehicles, electric aircraft, and electric powered ships. Among them, a submarine uses a high power battery for an energy storage. When the battery of a submarine is discharged, a diesel generator generates AC power, and then AC/DC power converter change AC power to DC power for charging the battery. Therefore, in order to lower the current capacity of the diesel generator, it is necessary to use an AC/DC converter with a high input power factor. And, a power converter with a large power capacity must have high stability because it can lead to a major accident when a failure occurs. However, the control algorithm using the traditional PI controller is difficult to satisfy stability and dynamic characteristics. In this paper, we design the high power AC/DC converter with high input power factor for battery charging systems. And, we propose a stable control algorithm. The validity of the proposed method is verified through simulation and experiments.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.53-56
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• 2008

In this paper, we propose the battery charging device for electric bicycle using photovoltaic power. DC voltage from the solar cells is low, it needs to be step-up by the power conversion device. The power conversion device applied to this paper is phase-shift full-bridge converter. This converter steps-up from 12${\sim}$22[Vdc] to 36[Vdc] for charging the battery of electric bicycle. Phase-shift full-bridge converter(PSFB) can obtain twice as much DC voltage compared with half-bridge converter, thus it has lower current stress less than half-bridge converter. It is simulated and tested the battery charging device using photovoltaic power.