• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.13-14
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• 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.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.177-178
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• 2012

In spite of its compactness and lightness, conventioan boost converter is not preferred for the charge applications. In this paper, a non-isolated boost converter topology for the Li-Ion battery suitable for fuel cell powered laptop computer is proposed and analyzed. The proposed converter has an additional inductor at the output to reduce the output ripple current and voltage. This feature makes it suitable for the charger application by eliminating the disadvantages of the conventional non-isolated boost converter mentioned above.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.443-447
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• 2013

This paper deals with LLC resonant converter of on-board charger for electric vehicle charging. Generally, the on-board charger must have a very widely charging voltage, higher efficiency, higher power factor, lower volume and lower weight. For reducing the switching losses, voltage and current stress of the device, the on-board charger is apply the half-bridge LLC resonant converter topology. To have a wide voltage range, it is design the hardware parameters and determine the switching frequency range of the LLC resonant converter. The experimental results show a wide charge voltage.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.5
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• pp.369-375
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• 2010

This paper presents a design and implementation of 3.3 kW on-board battery charger for electric vehicles or plug-in hybrid electric vehicles. Considering characteristics of the electric vehicles, a series-loaded resonant dc-dc converter and frequency control scheme are adopted to improve efficiency and reliability, and to reduce volume and cost. The developed on-board battery charger is designed and implemented by using high frequency of 80-130 kHz and zero voltage switching method. The experimental result indicates 92.5% of the maximum efficiency, 5.84 liters in volume, and 5.8kg in weight through optimal hardware design.

• Journal of IKEEE
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• v.19 no.2
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• pp.201-209
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• 2015

This paper describes a battery charger using photovoltaic energy harvesting with MPPT control. The proposed circuit harvests maximum power from a PV(photovoltaic) cell by employing MPPT(Maximum Power Point Tracking) control and charges an external battery with the harvested energy. The charging state of the battery is controlled according to the signals from a battery management circuit. The MPPT control is implemented using linear relationship between the open-circuit voltage of a PV cell and its MPP voltage such that a pilot PV cell can track the MPP of a main PV cell in real time. The proposed circuit is designed in a $0.35{\mu}m$ CMOS process technology and its functionality has been verified through extensive simulations. The maximum efficiency of the designed entire system is 86.2% and the chip area including pads is $1.35mm{\times}1.2mm$.

• Journal of Power Electronics
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• v.17 no.1
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• pp.31-40
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• 2017

A novel voltage-fed single-stage power factor correction (PFC) full-bridge converter based on asymmetric phase-shifted control for battery chargers is proposed in this paper. The attractive feature of the proposed converter is that it can operate in a wide output voltage range without an output low-frequency ripple, which is indispensable in battery charger applications. Meanwhile, the converter can maintain a high power factor and a controllable dc bus voltage over a wide output voltage range. In this paper, the realization of PFC and the operation principle of asymmetric phase-shifted control are given. A small-signal analysis of the proposed single-stage power factor correction (PFC) full-bridge converter is performed. Experimental results obtained from a 1kW experimental prototype are given to validate the feasibility of the proposed converter. The PF is higher than 0.97 over the entire output voltage range with the proposed control strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1523-1528
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• 2011

This paper proposes buck-type charging method using motor inductance, 3-phase inverter and bi-directional converter without an additional charger in plug-in hybrid electric vehicles. The proposed system has advantages over the conventional system such as high charging efficiency, high power factor, and low total harmonic distortion. The validity of each methods are verified by theoretical analysis and simulation.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.141-142
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• 2011

The increase in oil prices and the rising environmental concerns are boost the electric vehicle supply. Vehicle manufactures understand this trend quite well and plan to increase the production of electric vehicle(EV) such as Nissan LEAF and GM VOLT etc.. The growth of intermittent renewable energy sources such as solar and wind power requires utilities to find additional grid coupled energy storage and regulation capacity. EVs have a battery pack and a charger. The charger can be able to deliver power back to the grid from the vehicle's battery as well as charge the battery. The concept of deploying EVs to stabilize the electric power grid is generally referred to as Vehicle-to-Grid(V2G). We present the grid service using V2G.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.93-100
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• 2013

Generally, the conventional battery charging system using an analog method has the large, heavy hardware and low efficiency. Also, it has the disadvantage that it is necessary to replace the control circuit on the basis of the characteristic curve of the specific battery cell. The proposed programmable digital LLC resonant charging system use high efficiency control system(CC-CV), and has characteristic a small hardware and advantage that a digital programming of the voltage, current, and battery capacity characteristics can be flexible. The system proposed the use of Half-bridge LLC resonant converter is possible to improve efficiency and reduce switching losses by using ZVS topology. Further, a constant voltage - constant current(CC-CV) control algorithm apply to the charger which using a buck converter. The performance of the proposed system is demonstrated through experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.305-311
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• 2017

In this paper, the LLC resonant converter battery charger, using adaptive turn ratio scheme, is proposed to achieve high efficiency and wide range output voltage. The LLC converter high frequency transformer has an adaptively changed turn ratio by the auxiliary control circuitry. As a result, the optimal converter design with a large magnetizing inductance is easily achieved to minimize the conduction and the turn-off losses while providing widely regulated voltage gain capability to properly charge the Li-ion battery. The proposed converter operational principle and the optimal design considerations are illustrated in detail. Finally, several simulation results verify the proposed LLC resonant converter's effectiveness.