• Journal of IKEEE
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• v.15 no.4
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• pp.324-329
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• 2011

In recent years, the performance and functions of portable devices has increased. so it requires more power efficiency and energy density while using the battery for a long time. therefore Battery pack which are made up from several battery cells in series in order to achieve higher operating voltage is being used. when using a Li-ion battery, we need a protection circuit to protect from overcharge, over discharge, high temperature and over current. Also, when using battery pack, we need to Cell voltage balancing circuit that each cell in tune with the balancing. In this paper, the proposed IC is applicable by mobile devices as well as E-bike, hybrid vehicles, electric vehicles, and is expected to contribute to the development of domestic PMIC.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.347-349
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• 2007

Charge equalization scheme for HEV lithium-ion battery system is proposed in this paper, where all the primary windings with in parallel bi-directional switches are coupled in series to provide the equalizing energy from the whole battery string to the specific under charged cells. Moreover, to realize minimized size of equalization circuit employing the proposed cell balancing scheme, the optimal power rating design rule according to equalization time and SOC distribution of imbalance is proposed. A prototype of HEV lithium-ion battery system of four cells shows the outstanding charge equalization performance while maintaining greatly reduced size of cell balancing circuit.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.193-199
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• 2014

The series connected battery cells are mainly used in high voltage battery pack application. However parameter inequality of each battery cell makes battery voltage imbalance problem. In this paper, a new balancing circuit utilizing converter scheme for the series connected battery cells is proposed. Proposed circuit offers easy control and fast equalization time. Moreover the circuit can be used in a practical application because it has high modularity and can operate during the charging/discharging cycle. To show its superiorness and effectiveness, the principle of proposed circuit is explained with computer simulation and experiment is carried out using lithium-ion battery.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.367-376
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• 2016

This paper presents a cell balancing method for a single switch flyback converter with a multi-winding transformer. The conventional method using a flyback converter with a multi-winding transformer is simple and easy to control, but the voltage of each secondary winding coil might be non-uniform because of the unequal effective turn-ratio. In particular, it is difficult to control the non-uniform effect using turn-ratios because secondary coil has a limited number of turns. The non-uniform secondary voltages disturb the cell balancing procedure and induce an unbalance in cell voltages. Individual cell control by adding a switch for each cell can reduce the undesirable effect. However, the circuit becomes bulky, resulting in additional loss. The proposed method here uses the conventional flyback converter with an adjustment made to the output filters of the cells, instead of the additional switch. The magnitude of voltage applied to a particular cell can be reduced or increased according to the adjusted filter and the selected switching frequency. An analysis of the conventional converter configuration and the filter design method reveals the possibility of adequate cell balancing control without any additional switch on the secondary side.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.5
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• pp.73-80
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• 2013

Recently, Li-ion battery is regarded as a potential energy storage device in the lime light and it can supply power to the satellite very effectively during eclipse. Because it has better features as high voltage range, large capacity and small volume than any other battery. Generally, multi cells are connected in series to use Li-ion batteries in satellite application. Since the internal resistance of cells is different each other, voltage in some cells can be overcharged or undercharged, so capacity of the cell is reduced and the life of whole battery pack is decreased. Therefore, a voltage balancing circuit with Fly-back converter is proposed and the voltage equalization of each cell is verified the prototype in this paper.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.451-459
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• 2022

Recently, in accordance with the demand for a large capacity of a secondary battery according to an increase in the demand for energy storage devices, a modular series battery configuration is essential. Accordingly, various cell balancing techniques have been proposed to prevent high efficiency and performance degradation of the battery. In this paper, propose a battery voltage balancing topology consisting of a flyback DC/DC converter type of a SIMO (Single-Input-Multiple Output) two-switch configuration for a series battery configuration. The proposed topology shows a structure in which a DC/DC converter connected to each module and a battery cell share one transformer. The topology cell balancing operation is a principle in which the voltage balancing converter of the battery converges to the same value through a transformer that shares a magnetic flux with the cells constituting the module through a single high-frequency transformer. In this paper, the dynamic characteristics analysis of the proposed circuit using PSIM was based and it was verified through experiments on one module.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.240-249
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• 2018

Individual DC voltage balance problem is an inherent issue for cascaded H-bridge (CHB) based converter. When the CHB-based static synchronous compensator (STATCOM) is operating at zero current mode, the software-based individual DC voltage balancing control techniques may not work because of the infinitesimal output current. However, the different power losses of each cell would lead to the individual DC voltages unbalance. The uneven power losses on the local supplied cell-controllers (including the control circuit and drive circuit) would especially cause the divergence of individual DC voltages, due to their characteristic as constant power loads. To solve this problem, this paper proposes an adaptive voltage balancing module which is designed in the cell-controller board with small size and low cost circuits. It is controlled to make the power loss of the cell a constant resistance load, thus the DC voltages are balanced in zero current mode. Field test in a 10kV STATCOM confirms the performance of the proposed method.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.228-229
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• 2010

This paper presents an active voltage balancing approach using a forward fly-back power converter. In the proposed balancing scheme, cell with the higher voltage is selected to extract the extra energy and then a proportion of this extracted energy is distributed to other supercapacitors via the proposed circuit. A system structure consisting of five supercapacitors is built up to verify operation of the proposed scheme.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.26-27
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• 2011

This paper focuses on the zero-voltage/zero current transition voltage equalization circuit for the series connected battery cell. By adding auxiliary resonant cells at the main switching devices such as MOSFET or IGBT, zero current switching is achieved and turned off loss of switching elements is eliminated and by the voltage/second balancing of the inductor, zero voltage switching can be applied to switching element. Transformer coupling between battery cells and ZVZCT (Zero Voltage Zero Current Transition) switching method allow the fast balancing speed and high frequency operation, which reduces the size and weight of the circuit. The validity of the battery equalization is further verified using simulation involving four lithium-ion battery cell models.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.187-193
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• 2004

For a power source of usual electronic devices such as PDA, smart phone, UPS and electric vehicle, the battery made of serially connected multiple cells is generally used. In this case, if there are some unbalanced among cell voltages, the total lifetime and the total capacity of the battery are limited to a lower value. To maintain a balanced condition in cells, an effective method of regulating the cell voltage in indispensable. In this paper, we propose the design of a balancing circuit for electronic appliances. The balancing system was controlled by a micro-controller which enables to implement the balancing action during charging period. Proposed method has been verified by the experiment using the charger and recorder. The experimental results show that the individual battery equalization can improve battery capacity and battery lifetime and performance through an extended operational time.