Stability and Control Analysis for Series-Input/Parallel-Output Cell Balancing System for Electric Vehicle Battery Packs
01 Jan 2022-Vol. 6, pp 1388-1393
TL;DR: In this paper, the authors present a stability analysis for an $N$ -cell battery module and provide insight for design of embedded controllers, where a simple resistive circuit is used to drain current from the battery cell, while sophisticated control schemes and advanced circuitry may be employed.
Abstract: Battery management implement cell balancing algorithms to equalize state of charge of series-connected cells in a battery pack. Balancing strategies range from passive, where a simple resistive circuit is used to drain current from the battery cell, to active, where sophisticated control schemes and advanced circuitry may be employed. Recent development of active balancing control strategies for a modular cell-balancing architecture utilize low-voltage bypass DC-DC converters and a shared low-voltage dc bus. Although these systems show promise in preliminary experiments, questions remain over the inherent stability properties of the architecture. This letter presents a stability analysis for an $N$ -cell battery module and provides insight for design of embedded controllers.
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TL;DR: In this paper , the evolutions and challenges of state-of-the-art battery technologies and battery management technologies for hybrid and pure EVs are reviewed, revealing the major features, pros and cons, new technological breakthroughs, future challenges, and opportunities for advancing electric mobility.
80 citations
TL;DR: A modular topology based on a DC-DC three-level boost converter is used and the commandable areas of the proposed structure are examined for different operating points and this topology is validated by simulations and experimental results.
15 citations
TL;DR: In this article , a new cell voltage adaptive balancing control method in both charging and discharging modes is proposed to improve the balancing time of battery energy storage systems with decoupled and converters serial-connected.
Abstract: To improve the balancing time of battery energy storage systems with “cells decoupled and converters serial-connected,” a new cell voltage adaptive balancing control method in both charging and discharging modes is proposed in this study. The overall system architecture and basic operating principle of the active balancing system with “cells decoupled and converters serial-connected” are presented first. Then, by dynamically regulating the balancing acceleration coefficient of each cell according to the cell voltage deviation, the adaptive balancing control of cell voltage in charging and discharging modes is analyzed. An experimental prototype consisting of six smart cells is developed, and experiments in charging and discharging modes were carried out. The experiment results demonstrate that compared with the balancing process with a static acceleration coefficient, the proposed adaptive balancing control of cell voltage shows significant improvement in balancing speed and smaller cell voltage discrepancy.
3 citations
19 Mar 2023
TL;DR: In this article , an active balancing method-based battery management system for different cell chemistry structures to be used in behind-the-meter storage (BTMS) applications is presented, where a supervisory controller monitors all the cell voltage, current, and state of charge (SOC) values.
Abstract: Battery management systems (BMS) are essential for a battery pack's safe operation and longevity. This paper presents an active balancing method-based BMS for different cell chemistry structures to be used in behind-the-meter storage (BTMS) applications. The proposed system utilizes modular isolated dual active bridge (DAB) DC/DC converters to actively balance the battery pack through a low voltage (LV) bus. A supervisory controller monitors all the cell voltage, current, and state of charge (SOC) values. Based on the estimation of the SOCs, reference currents for the DAB converters are generated by the supervisory controller. Detailed modeling and the control approach of the modular DAB converters are presented in the paper. Moreover, the control strategy of the supervisory control is also analyzed. The proposed method and structure can be extended to any combination of the number of cells to design the battery pack. Simulation results are provided for a system consisting of three cells in parallel to form a cell block and three cell blocks in series to form the battery module. Experimental results are provided for three modular DAB converters operating with a LiFeMnPO4 prismatic cell with 3.2V, 20Ah rated values.
TL;DR: In this article , the authors reviewed the linkage between the latest research contributions, issues associated with TSCC and SSC, and the performance evaluation of the techniques, and subsequently identified the research gaps and proposed SSC control with state of charge consideration for further research studies.
Abstract: The growing trend for electric vehicles (EVs) and fast-charging stations (FCSs) will cause the overloading of grids due to the high current injection from FCSs’ converters. The insensitive nature of the state of charge (SOC) of EV batteries during FCS operation often results in grid instability problems, such as voltage and frequency deviation at the point of common coupling (PCC). Therefore, many researchers have focused on two-stage converter control (TSCC) and single-stage converter (SSC) control for FCS stability enhancement, and suggested that SSC architectures are superior in performance, unlike the TSCC methods. However, only a few research works have focused on SSC techniques, despite the techniques’ ability to provide inertia and damping support through the virtual synchronous machine (VSM) strategy due to power decoupling and dynamic response problems. TSCC methods deploy current or voltage control for controlling EVs’ SOC battery charging through proportional-integral (PI), proportional-resonant (PR), deadbeat or proportional-integral-derivative (PID) controllers, but these are relegated by high current harmonics, frequency fluctuation and switching losses due to transient switching. This paper reviewed the linkage between the latest research contributions, issues associated with TSCC and SSC techniques, and the performance evaluation of the techniques, and subsequently identified the research gaps and proposed SSC control with SOC consideration for further research studies.
References
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Book•
01 Jan 1987
TL;DR: Das Buch behandelt die Systemidentifizierung in dem theoretischen Bereich, der direkte Auswirkungen auf Verstaendnis and praktische Anwendung der verschiedenen Verfahren zur IdentifIZierung hat.
Abstract: Das Buch behandelt die Systemidentifizierung in dem theoretischen Bereich, der direkte Auswirkungen auf Verstaendnis und praktische Anwendung der verschiedenen Verfahren zur Identifizierung hat. Da ...
20,436 citations
18 Nov 2008
TL;DR: In this paper, the theory behind the proposed balancing methods for battery systems within the past twenty years is presented and comparison between the methods is carried out and different balancing methods are grouped by their nature of balancing.
Abstract: The trend toward more electric vehicles has demanded the need for high voltage, high efficiency and long life battery systems. A complete battery system consists of the following parts: protection, management and balancing. Of the three parts, balancing is the most important concerning the life of the battery system because without the balancing system, the individual cell voltages will drift apart over time. The capacity of the total pack will also decrease more quickly during operation which will result in the fail of the total battery system. This condition is especially severe when the battery has a long string of cells (high voltage battery systems) and frequent regenerative braking (charging) is done via the battery pack. This paper presents the theory behind the proposed balancing methods for battery systems within the past twenty years. Comparison between the methods is carried out and different balancing methods are grouped by their nature of balancing.
627 citations
13 Oct 2011
TL;DR: In this article, a review and comparison between the different cell balancing topologies for battery string based on MATLAB/Simulink® simulation is presented, according to circuit design, balancing simulation, practical implementations, application, balancing speed, complexity, cost, size, balancing system efficiency, voltage/current stress, etc.
Abstract: Battery systems are affected by many factors, the most important one is the cells unbalancing. Without the balancing system, the individual cell voltages will differ over time, battery pack capacity will decrease quickly. That will result in the fail of the total battery system. Thus cell balancing acts an important role on the battery life preserving. Different cell balancing methodologies have been proposed for battery pack. This paper presents a review and comparisons between the different proposed balancing topologies for battery string based on MATLAB/Simulink® simulation. The comparison carried out according to circuit design, balancing simulation, practical implementations, application, balancing speed, complexity, cost, size, balancing system efficiency, voltage/current stress … etc.
371 citations
TL;DR: In this paper, the authors describe photovoltaic (PV) module architectures with parallel-connected sub-module-integrated dc-dc converters (subMICs) that improve efficiency of energy capture in the presence of partial shading or other mismatch conditions.
Abstract: This paper describes photovoltaic (PV) module architectures with parallel-connected submodule-integrated dc-dc converters (subMICs) that improve efficiency of energy capture in the presence of partial shading or other mismatch conditions. The subMICs are bidirectional isolated dc-dc converters capable of injecting or subtracting currents to balance the module substring voltages. When no mismatches are present, the subMICs are simply shut down, resulting in zero insertion losses. It is shown that the objective of minimum subMIC power processing can be solved as a linear programming problem. A simple close-to-optimal distributed control approach is presented that allows autonomous subMIC control without the need for a central controller or any communication among the subMICs. Furthermore, the proposed control approach is well suited for an isolated-port architecture, which yields additional practical advantages including reduced subMIC power and voltage ratings. The architectures and the control approach are validated by simulations and experimental results using three bidirectional flyback subMICs attached to a standard 180-W, 72-cell PV module, yielding greater than 98% module-level power processing efficiency for a mismatch less than 25%.
283 citations
TL;DR: In this paper, a hybrid cascaded multilevel converter which involves both battery energy management and motor drives is proposed for electric vehicles, where each battery cell can be controlled to be connected into the circuit or to be bypassed by a half-bridge converter.
Abstract: In electric vehicle (EV) energy storage systems, a large number of battery cells are usually connected in series to enhance the output voltage for motor driving. The difference in electrochemical characters will cause state-of-charge (SOC) and terminal voltage imbalance between different cells. In this paper, a hybrid cascaded multilevel converter which involves both battery energy management and motor drives is proposed for EV. In the proposed topology, each battery cell can be controlled to be connected into the circuit or to be bypassed by a half-bridge converter. All half-bridges are cascaded to output a staircase shape dc voltage. Then, an H-bridge converter is used to change the direction of the dc bus voltages to make up ac voltages. The outputs of the converter are multilevel voltages with less harmonics and lower dv/dt, which is helpful to improve the performance of the motor drives. By separate control according to the SOC of each cell, the energy utilization ratio of the batteries can be improved. The imbalance of terminal voltage and SOC can also be avoided, fault-tolerant can be easily realized by modular cascaded circuit, so the life of the battery stack will be extended. Simulation and experiments are implemented to verify the performance of the proposed converter.
227 citations