Multi-constrained dynamic power estimation of battery system in series connection considering cell inconsistency
Multiple lithium-ion cells are usually connected in series into a battery system in series connection, to meet the requirements of energy and voltage level for the rail transit equipment and electric vehicles. To solve the problem of inaccuracy in estimating state of power (<italic>SOP</ita...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Department of Electric Drive for Locomotives
2022-05-01
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| Series: | 机车电传动 |
| Subjects: | |
| Online Access: | http://edl.csrzic.com/thesisDetails#10.13890/j.issn.1000-128X.2022.03.011 |
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| Summary: | Multiple lithium-ion cells are usually connected in series into a battery system in series connection, to meet the requirements of energy and voltage level for the rail transit equipment and electric vehicles. To solve the problem of inaccuracy in estimating state of power (<italic>SOP</italic>) due to cell inconsistency, this paper proposes a multi-constrained dynamic power estimation method based on a <italic>SOP</italic> errors predictor for the battery system in series connection was proposed. On the one hand, according to the operating characteristics and constraints on the operating parameters of the battery system in series connection, a <italic>SOP</italic> basic value was forecasted by a multi-constrained dynamic power estimation method. On the other hand, a neural network-based <italic>SOP</italic> errors predictor was proposed on the basis of terminal voltage inconsistency among cells in the battery system. The battery system <italic>SOP</italic> error was caused by voltage inconsistency. The estimated battery system <italic>SOP</italic> was finally attained by the sum of the <italic>SOP</italic> error and the <italic>SOP</italic> basic value. A system simulation model was created in the MATLAB/Simulink environment to verify the accuracy of the proposed method. The battery system <italic>SOP</italic> was estimated by the presented method for a duration of 30 seconds, 2 minutes and 5 minutes respectively. The results show that the estimated <italic>SOP</italic> is always consistent with the measured <italic>SOP</italic> with a forecast error approximating to 2% of the rated continuous peak power. Moreover, by comparison with the estimation results by other methods, the estimated <italic>SOP</italic> using the proposed method is the closest to the measured one. Therefore, for a battery system in series connection with inconsistent cells, its <italic>SOP</italic> can be estimated accurately by the proposed method, which provides a way to improve the life cycle management ability of the large capacity battery system. |
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| ISSN: | 1000-128X |