Switched capacitor system for automatic series battery equalization

Pascual, C.; Krein, P.T.

doi:10.1109/apec.1997.575744

Cited by 413 publications

(174 citation statements)

References 5 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 cell balancing circuit based on an SCC and operation modes of the circuit are shown in Figure 5 [8,15,16,21]. In order to simplify the analysis for circuit operation mode, it is assumed that the circuit has two cells and V Cell1 > V Cell2 .…”

Section: Cell Balancing Circuit Using Sccmentioning

confidence: 99%

“…At the same time, Sa1 and Sa2 conduct, so the Cm will be charged by the VM1 through the Sa1 and Sa2 so that the VCm increases gradually to a steady state period. The instantaneous voltage and current of the balancing capacitor in this mode can be given by Equations (14) and (15).…”

Section: Operational Principlementioning

confidence: 99%

“…Recently, the cell balancing methods have been introduced [10][11][12][13][14][15][16][17][18][19][20] and reviewed [7,8,[21][22][23], as represented in Figure 1. There are two main ways to equalize a battery cell, which are passive and active methods [8,22].…”

Section: Introductionmentioning

confidence: 99%

“…However, this balancing technique requires an intelligent control and a large number of switches, resulting in relative complexity and high cost. In addition, a balancing method based on a switched capacitor circuit (SCC) [11,15,26,27] has been widely utilized in energy storage applications thanks to advantages such as simple design and control and elimination of a voltage sensor for each cell. Importantly, the SCC can be employed in the modular method as well.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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%

Section: Cell Balancing Circuit Using Sccmentioning

confidence: 99%

Section: Operational Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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A charge equalization scheme for battery string with charging current allocation

Hsieh

Yang

2021

Circuit Theory & Apps

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Summary This research proposes a charge equalization scheme based on a flyback converter with the polarity‐inverting folding switches together with a set of selection switches for series‐connected batteries. By the selection switches, the converter can provide an additional charging current to the battery with the lowest loaded voltage. In addition to intervening a low current charging to prolong the discrepant charging, a finalizing individual charging is performed to ensure charge equalization even under extremely unbalanced situation. Thus, all the batteries can be allocated with appropriate electric charge through the proposed charge‐balance strategy to make the voltage of all batteries be even after the charging process. Three sets of experiments with different initial conditions are performed. Experimental results show that the charge imbalance can be effectively reduced after the regular current charging for most practical cases. All batteries can be charged to their full capacities with individual charging, even under extremely unbalanced situation. Eventually, the voltage difference among batteries can be alleviated to about 50 mV.

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An any‐unit‐to‐any‐unit method for hybrid‐structured voltage equalizer in series‐connected battery/super‐capacitor strings

Zhang

et al. 2022

Circuit Theory & Apps

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The slow balancing speed of switched-capacitor (SC)-based equalizers makes this structure difficult to apply in series-connected battery strings. In order to reduce the number of energy conversion processes and achieve leapfrog transmission of energy, a hybrid-structured voltage equalizer (HSVE) is developed in this work for battery strings to achieve high-speed any-unit-to-any-unit (AU2AU) equalization, in which each unit can also achieve internal balance in any arbitrary imbalance status. Compared to the conventional equalizers using complex monitoring and control strategy, the proposed equalizer does not need any cell monitoring circuits-all MOSFETs are triggered by a pair of complementary pulse signals with a fixed switching frequency and constant duty ratio, and electricity can automatically and directly exchange among all battery cells. Hardware experiments on super-capacitors and Li-ion batteries are conducted in this study, which prove the feasibility of the proposed voltage equalizer. The proposed battery management strategy will have wide applications in modern battery-related industries such as electric vehicles (EVs).

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Switched capacitor system for automatic series battery equalization

Cited by 413 publications

References 5 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

A charge equalization scheme for battery string with charging current allocation

An any‐unit‐to‐any‐unit method for hybrid‐structured voltage equalizer in series‐connected battery/super‐capacitor strings

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