Electro-Thermal Modeling and Simulation of a Battery-Integrated PECIN Multilevel Inverter Using a Switching Model Approach

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper develops a comprehensive electro-thermal simulation framework for a battery-integrated Parallel Enhanced Commutation Integrated Nested multilevel inverter using a switching model approach, with novel network analysis algorithms to avoid computationally intensive high-dimensional matrix inversion and improve computational efficiency.

1. The acronym PECIN is first used in the manuscript title, while its full name and corresponding abbreviation are not clearly marked in the Abstract section. This may create difficulties for readers unfamiliar with this specialized topology to quickly identify the core research object of the paper.
2. In Section 5.1 and Section 5.3, the authors introduce the basic software and hardware environment for the simulation verification, but key details that directly affect the reproducibility of the research are not fully disclosed, including the specific type of fixed-step solver used in the Simulink model, the memory configuration of the test hardware, and the operating system.
3. In Section 4.3, the authors note that the outer iteration loop can be omitted through parallel execution of the current contribution calculations for each voltage source (Line 569), but still conclude that the time complexity of the algorithm remains O(N_SM²). This description lacks a clear distinction between algorithmic time complexity and actual wall-clock execution time, which may cause confusion for readers.
4. The proposed simulation model is parameterized based on a laboratory-scale PECIN MLI prototype introduced in Section 5.1, but no comparative validation between the simulation results and experimental measurement data from this prototype is provided in Section 5 or any other section of the manuscript. This makes it difficult to fully verify the accuracy and reliability of the proposed model in practical applications. It is recommended to supplement the corresponding experimental validation results, or clearly explain the reasons for the absence of such validation.
5. In Section 4.2 and Appendix A.1, the authors state that the proposed model is adaptable to various system configurations including different AC and DC charging modes, and provide a dedicated circuit topology for single-phase/DC charging operation. However, only the three-phase AC charging scenario is verified in the simulation case study, with no simulation or performance analysis conducted for the other mentioned configurations.
6. In Section 5.1, the authors mention that parameter variations between submodules are considered for the Electrical Battery Cell Model (EBM) and Electrical Trace Model (ETM) assuming a normal distribution (Line 651). However, in the simulation case study in Section 5.2, all battery cells are set to an identical initial SoC of 50% (Line 674), and no analysis of the model’s ability to characterize and handle cell inconsistency is provided, despite this being a key advantage of the cascaded MLI topology. It is recommended to supplement relevant simulation analysis to demonstrate the model’s performance in scenarios with cell parameter and SoC inconsistencies.
7. In Section 4.4, the proposed temperature distribution model includes a thermal resistance term for the cooling system to support active cooling scenarios, while in the simulation case study in Section 5.2, the heat sink is omitted and only free convection is considered (Line 677-678). It is recommended to supplement relevant analysis or clarify the applicable thermal boundary conditions of the proposed model.
8. The figures and tables in this paper require further standardization and refinement. For instance, the subfigures in Figs. 15 - 17 should be numbered in the sequence of a, b, c; in Fig. 15a, there is unnecessary overlap and occlusion; and the format of the three-line table in Table 3 needs further improvement.

Overall, this manuscript presents a comprehensive, well-structured, and novel study on the electro-thermal modeling of battery-integrated PECIN multilevel inverters. The work involves a significant amount of workload. With appropriate revisions addressing the above comments, this manuscript is suitable for publication in Batteries.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The reviewed article proposes a new method of electro-thermal modelling of multilevel inverters. This article contains valuable results of investigations, but the description of these results needs an improvement. Therefore, this paper needs revision. In the revised version of this article the Authors should take into account the following remarks.

1. The article is very long and therefore it is difficult to analyze. I recommend to short this article.
2. This article contains up to 87 equations. In my opinion, not all of them are important.
3. All the symbols used in the article should be explained in the body of the article.
4. The structure of the article should be modified. At first the block diagram of the modeled network should be presented. Next the electrical models of each block should be presented and finally the thermal models of these blocks should be presented.
5. Figs. 15-17 are of poor quality. It should be improved. Particularly, the y-axes should be higher.
6. Any results of measurements should be compared with results of calculations.
7. In the reference list some papers on modelling batteries, e.g. by Professor Ptak, should be included. 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this manuscript, the authors studied an electrothermal simulation framework for the Parallel Enhanced Commutation Integrated Nested multilevel inverter. The idea is good, but the work needs some major modifications as follows;

• In the abstract section, the need to focus on key things such as results, methods, and showing the novelty of this work rather than previous studies.
• Figure captions are too general. These should be broad enough to clearly understand the theme of the figure.
• Many equations are without references and explanations, restricting the reproducibility of this work.
• Many sections contain just normal general details. The author needs to add a more detailed and comprehensive scientific discussion for each study.
• What is the impact of this study when integrated with experimental?
• Tables caption and discussion also need to be improved. Despite adding just results, authors need to provide further details about the outcomes and their impact.
• Figures 16 and 17 labelling is non-readable. Please provide the high-quality images for publications.
• Table 3, please separate the electrical and thermal columns and make such changes in other parts where needed to provide ease for the readers.
• Conclusion is generic; please revise it extensively.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The Authors improved the article, but some remarks are not properly addressed.

Now, the article is too long.

I recommend to short the article and reduce the number of the presented equations. 

The reviewed paper contains over 80 equations. Many of these equations are repeated in the descriptions of proposed algorithm. Therefore, I suggested to reduce the number of presented equations (in the body of the paper) or move the descriptions of proposed algorithms to an appendix. In my opinion, only the final version of the equations should be included in the paper. If some equations have similar forms (e.g. Eqs. (9) and (10), Eqs. (11-13), Eqs. (18-19), etc.), it is a good solution to present only one of these equations and a differences shortly describe in the comment to this equation. Using this rule, the number of equations can be reduced twice.

Additionally, in Figs. 8 and 9 should be shown only finalization steps.
 On the other hand, it is low probability that many readers of the journal Batteries would like to read so long article. Therefore, I suggested to shorten this article. In my opinion, the main part of the article should not be longer than 20 pages. Other information can be included in appendixes. Such a changes will make the reading of the article more fluent.

They are only redaction suggestions. If the Authors would like to neglect they, it is possible and the article could be accepted in its current form, but the reading of it will be tiring.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The revised version could be considered for publication. 

Author Response

The authors thank the reviewer for the positive evaluation of the revised manuscript and for the constructive comments provided throughout the review process.