A Modular Fast Cell-to-Cell Battery Voltage Equalizer

Dam, Shimul Kumar; John, Vinod

doi:10.1109/tpel.2020.2972004

Cited by 38 publications

(32 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…the design criteria for switches Q 4 and Q 1 to achieve ZVS operation under idealized conditions can be obtained. The magnetizing currents at points t 5 and t 6 need to meet the conditions given in (7).…”

Section: Zvs Conditionsmentioning

confidence: 99%

“…Different equalization units (EUs) have been proposed to achieve energy transfer between cells. In general, converters composed of active switches, such as switched capacitors, 5,6 quasiresonant/resonant converters, 6 phase-shifted half-bridge converter, 7 and buck-boost converters, [5][6][7][8] can be used as EUs. However, the obvious disadvantage of using a converter as the EU is that a converter is required between every two adjacent cells connected in series, which leads to an increase in the complexity, cost, and size of the system.…”

mentioning

confidence: 99%

“…4.1 | Minimum magnetizing current at t 6 , i Lm m in (t 6 )By substituting L m ¼ 0:86 μH and C os ¼ 340 pF into(7), Z 0 can be obtained as 35.56 Ω. By substituting V in ¼ 15 V and Z 0 ¼ 35:56 Ω into (7) and (8), respectively, the relationship between ji Lm m in ðt 6 Þj and V o can be obtained, as shown inFigure 7.…”

mentioning

confidence: 99%

See 2 more Smart Citations

A bidirectional converter with integrated voltage equalizer for series‐connected supercapacitors

Yang

Jia

Wang

et al. 2022

Circuit Theory & Apps

View full text Add to dashboard Cite

Energy storage systems include not only a charge/discharge bidirectional converter but also a separate voltage equalizer. This paper proposes a bidirectional converter with an integrated voltage equalizer, which saves a DC-AC converter, thus significantly reducing the size, cost, and complexity of the equalization circuit. In addition, integrating the equalizer into the bidirectional converter also has a positive impact on the realization of ZVS operation. Analytical models have been established that can be used for accurate prediction, optimal design, and effective control of the proposed converter. A control strategy is proposed, which not only enables the cells to be automatically balanced when the cell string is charged/discharged but also enables ZVS operation within a wide range of voltage changes and minimizes the RMS value of the primary current. An experimental prototype of 60 W applied to nine supercapacitors (SCs) in series was built, and the experimental results verified the theoretical analysis and demonstrated the characteristics of the proposed converter.bidirectional converter, supercapacitors (SCs), voltage equalizer, voltage multiplier 1 | INTRODUCTION Supercapacitors (SCs) have been widely used in portable electronic devices, regenerative energy systems, hybrid vehicles, uninterruptible power supplies, and so on, and because of their long service life, they are expected as an alternative to traditional rechargeable batteries. [1][2][3] Since the voltage of a single SC is low, typically 0-3.0 V, multiple SCs need to be connected in series to form a string to provide a higher voltage level. Due to the slight difference in characteristics between cells and the influence of the ambient temperature, the voltage of each cell in the series-connected SC string will gradually become unbalanced.Many methods for cell balancing have been proposed, each with different advantages and disadvantages. The active balance method transfers energy through an external circuit to achieve balance between the cells. According to the energy flow mode, these methods are classified into four types: cell-to-cell, cell-to-string, string-to-cell, and cell(s)-tostring-to-cell(s). 4 Compared with other types of equalizers, string-to-cell equalizers can achieve cell balance through a single power conversion stage. The number of active switches in these equalizers is usually small, and the control method is relatively simple. The low complexity of these equalizers is very attractive, especially suitable for small-and medium-sized energy storage systems.

show abstract

Section: Zvs Conditionsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

A bidirectional converter with integrated voltage equalizer for series‐connected supercapacitors

Yang

Jia

Wang

et al. 2022

Circuit Theory & Apps

View full text Add to dashboard Cite

show abstract

“…According to different energy transfer modes [7], battery equalization technology can be divided into passive equalization and active equalization. Passive equalization means that high-power batteries dissipate excess energy in the form of heat through dissipating components [8,9]. This method's structure and control strategy are straightforward, but the passive equalization does not make the most of the energy, resulting in a waste of energy.…”

Section: Introductionmentioning

confidence: 99%

Research on Alternating Equalization Control Systems for Lithium-Ion Cells Charging

Zhang

Huang

et al. 2021

WEVJ

View full text Add to dashboard Cite

Lithium-ion batteries which are used in electric vehicles cannot be charged to their maximum capacity at the end of the charging period, a situation which is caused by inconsistency between the battery cells. This paper takes the 18650 ternary lithium battery as the research object and proposes an alternate equalization control system in the charging process. This system takes SOC consistency to be the equalization variable. Through controlling the relay, this system realizes the alternate recombination between different batteries in order to form a series battery group for charging, which achieves the goal of SOC equalization of the entire battery group. The simulation result of charge equalization, based on Matlab/Simulink, shows that at the end of the charging simulation, the SOC inconsistency of the battery group reduced from 10% to 1%. Finally, an experimental platform was built in order to verify the experiment. During the charge balance experiment, the maximum SOC inconsistency between the batteries reduced from 1.542% to 1.035%. The SOC inconsistency at the end of charging reduced from 1.214% to 0.8%, which represents an improvement of the equalization effect of the control system. The experimental results are consistent with the simulation results, which proves the effectiveness of the system’s ability to control the battery SOC balance during the charging process.

show abstract

“…The first type of active equalizer uses multiple power converters or a multi-port power converter so that all the cells can take part in voltage equalization simultaneously. These equalizers can be classified into three categories: adjacent cell [3]- [8], multi-cell to stack [9]- [18], and multi-cell to multi-cell [19]- [28] equalizers, among which the multi-cell to multi-cell equalizers offer fastest voltage equalization. Each of these equalizers dedicates one converter port to each cell even though many of the cells in the cell stack may not require voltage equalization at a given point of time.…”

mentioning

confidence: 99%

A Selection Switch Based Cell-to-cell Battery Voltage Equalizer with Reduced Switch Count

Dam

2019

2019 IEEE Energy Conversion Congress and Exposition (ECCE)

Self Cite

View full text Add to dashboard Cite

A selection switch based cell-to-cell voltage equalizer requires only one dual-port dc-dc converter shared by all the cells. A cell-to-cell voltage equalizer is proposed that utilizes a capacitively level-shifted Cuk converter and low-frequency cell selection switches. The absence of isolation transformer and diodes in the equalizer leads to high efficiency, and the use of low-frequency selection switches significantly reduces the cost of the drive circuits. A low-frequency cell selection network is proposed using bipolar voltage buses, where the switch count is almost half, compared to the existing low-frequency cell-tocell equalizers for the case of a large number of cells. A novel approach for cell voltage recovery compensation is proposed, which reduces the number of operations of the selection switches and the equalization time. The proposed equalizer is implemented with relays and verified with an 8-cell Li-ion stack. The developed prototype shows the efficiency of over 90% and good voltage balancing performance during charging, discharging, and varying load conditions. Experimental results also show about one order of magnitude reduction in the number of relay switchings and a significant reduction in equalization time using the proposed voltage compensation.

show abstract

A Modular Fast Cell-to-Cell Battery Voltage Equalizer

Cited by 38 publications

References 34 publications

A bidirectional converter with integrated voltage equalizer for series‐connected supercapacitors

A bidirectional converter with integrated voltage equalizer for series‐connected supercapacitors

Research on Alternating Equalization Control Systems for Lithium-Ion Cells Charging

A Selection Switch Based Cell-to-cell Battery Voltage Equalizer with Reduced Switch Count

Contact Info

Product

Resources

About