A new battery equalizer based on buck-boost topology

Park, Sang‐Hyun; Kim, Taesung; Park, Jin-Sik; Moon, Gun-Woo; Yoon, Myung-Joong

doi:10.1109/icpe.2007.4692526

Cited by 42 publications

(28 citation statements)

References 3 publications

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“…Table 3 shows the comparison of the proposed topology and existing topologies in terms of a number of required components within the case of n cells connected in series. A buck-boost converter-based balancing topology [12,14,[36][37][38] or switched capacitor converter-based balancing topology [11,15,22,26,27,30] can be constructed with a reasonable number of components. However, the energy transfer of these topologies is limited between two adjacent cells (i.e., cell to cell balancing) when a large number of cells in SCBS increases (i.e., approximately 80 or more cells) resulting in relatively slow balancing speed and low balancing efficiency.…”

Section: Resultsmentioning

confidence: 99%

A Modular Cell Balancer Based on Multi-Winding Transformer and Switched-Capacitor Circuits for a Series-Connected Battery String in Electric Vehicles

Bui

Kim

et al. 2018

Applied Sciences

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Abstract:In this paper, a cell balancing topology for a series-connected Lithium-Ion battery string (SCBS) in electric vehicles is proposed and experimentally verified. In particular, this balancing topology based on the modular balancer consists of an intra-module balancer based on a multi-winding transformer circuit and an outer-module balancer based on a switched capacitor converter, both offering the potential advantages and over conventional balancing methods, including short equalization time, simple control scheme, elimination of voltage sensors. In addition, a number of cells in the SCBS can be easily extended in this circuit. Furthermore, a system structure and an operating principle of the proposed topology are analyzed and experimentally verified for three different cases. The voltages of all cells in the SCBS reached the balanced state regardless of the various arrangement of the initial voltage, where the energy efficiency of the circuit reached 83.31%. Our experimental realization of the proposed balancing topology shows that such a technique could be employed in electric vehicles.

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Section: Resultsmentioning

confidence: 99%

A Modular Cell Balancer Based on Multi-Winding Transformer and Switched-Capacitor Circuits for a Series-Connected Battery String in Electric Vehicles

Bui

Kim

et al. 2018

Applied Sciences

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“…They do not cause electrical energy wastage, although the structure of the balancing circuit and control strategies are complex, especially for a large electrical storage system with many series-connected cells. There are several different circuit topologies and control methods, such as capacitor-based [12][13][14], inductor-based [15,16], and converter-based methods [17][18][19][20]. The circuit components and main characteristics of various active balancing methods are summarized in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Optimal SoC Balancing Control for Lithium-Ion Battery Cells Connected in Series

et al. 2021

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The optimal state of charge (SoC) balancing control for series-connected lithium-ion battery cells is presented in this paper. A modified SoC balancing circuit for two adjacent cells, based on the principle of a bidirectional Cuk converter, is proposed. The optimal SoC balancing problem is established to minimize the SoC differences of cells and the energy loss subject to constraints of the normal SoC operating range, the balancing current, and current of cells. This optimization problem is solved using the sequential quadratic programming algorithm to determine the optimal duties of PWM signals applied to the SoC balancing circuits. An algorithm for the selection of the initial points for the optimal problem-solving process is proposed. It is applied in cases where the cost function has no decreasing part. Experimental tests are conducted for seven series-connected Samsung cells. The optimal SoC balancing control and SoC estimation algorithms are coded in MATLAB and embedded in LabVIEW to control the SoC balancing in real time. The test results show that the differences between the SoCs of cells converges to the desired range using the proposed optimal SoC balancing control strategy.

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“…However, when the unbalanced cells are far away from each other, the equalization transfer path is long, the equalization speed is slow and the energy loss is high. Direct cell-to-cell [28][29][30] , which is usually realized by a common energy storage element, such as capacitor, inductor and transformer. It can realize the direct balancing between the highest energy cell and the lowest energy cell, and obtain higher equalization efficiency.…”

Section: Introductionmentioning

confidence: 99%

Balancing Method Based on Flyback Converter for Series-Connected Cells

Cao

Lü

2021

IEEE Access

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For the various imbalances of series-connected cells, the existing balancing methods has the disadvantages of limited energy flow direction and unnecessary charge transfer. Based on flyback converter, this paper proposes a multi-winding input and multi-winding output bi-directional equalization topology. It can realize any cell (s) to any cell (s) balancing, which has the advantage of flexible balancing energy flow path. This paper adopts the control strategy of time-sharing participation in equalization according to the order of the initial state of charge (SOC) of cells, it can solve the problem of unnecessary energy transfer and simplify the control logic. In addition, it gets rid of the influence of energy loss of the circuit components on the setting of the fixed equalization end judgment value, whether equalization ends or not depends on the difference between the discharge cells and the charge cells in this paper, which has the advantage of random adaptive adjustment. In this paper, the operational principle of the proposed circuit are analyzed and the equalization strategy is described in detail. A comparison in balancing performance between the conventional equalization topology based on flyback converter and proposed topology is shown in static state. To verify the validity of the proposed method, the simulation experiment of four cells series-connected is carried out, and the simulation results show that the balancing method proposed in this paper has faster equalization speed and higher equalization energy transfer efficiency.

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A new battery equalizer based on buck-boost topology

Cited by 42 publications

References 3 publications

A Modular Cell Balancer Based on Multi-Winding Transformer and Switched-Capacitor Circuits for a Series-Connected Battery String in Electric Vehicles

A Modular Cell Balancer Based on Multi-Winding Transformer and Switched-Capacitor Circuits for a Series-Connected Battery String in Electric Vehicles

Optimal SoC Balancing Control for Lithium-Ion Battery Cells Connected in Series

Balancing Method Based on Flyback Converter for Series-Connected Cells

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