Development and Experimental Validation of a Reduced-Scale Single-Phase Modular Multilevel Converter Applied to a Railway Static Converter
Round 1
Reviewer 1 Report
The paper presents the development of a reduced-scale single-phase modular multilevel converter (MMC), as well as its experimental validation. It is difficult to find the papers' contributions, possibly due to the brief presentation and discussion of the direct state-of-the-art (SoA). Besides that, the author does not present the state of the art; any related work is discussed in the introduction, and thus the paper's contribution is not evident. Finally, proofreading is required and the results figures must be improved (The figures should be generated in the type of vector graph).
Suggestions:
Abstract: you must summarize the context description and state your contributions, in terms of their novelty (For me are not clear).
Introduction: You must introduce the most relevant reviews and surveys on the topic (e.g., https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9360490, https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8581571
) which should be discussed to explain the paper's contribution. Furthermore, this section may be extended in order to present the state of the art using more directly related references.
Results: The presented results are not clear to me. For instance: Report the experimental setup in detail to understand its implementation and limitations. A brief comparison with the SoA is required as the one presented in https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9360490 .
Conclusions: The conclusion must be improved. The conclusions and results analysis should be oriented not only toward the prototype functionality but also toward a comparison of its results with the state of the art.
Author Response
Reviewer 1
The paper presents the development of a reduced-scale single-phase modular multilevel converter (MMC), as well as its experimental validation. It is difficult to find the papers' contributions, possibly due to the brief presentation and discussion of the direct state-of-the-art (SoA). Besides that, the author does not present the state of the art; any related work is discussed in the introduction, and thus the paper's contribution is not evident. Finally, proofreading is required and the results figures must be improved (The figures should be generated in the type of vector graph).
Thank you for your valuable review and suggestion to improve our paper. The main contributions of the paper were improved and highlighted in this revised version, considering an expanded contextualization with the state-of-the-art regarding applications as well as different topologies for the Modular Multilevel Converter with a comparative table. Additional references were added and discussed in the introduction and the figures showing the results were improved.
Suggestions:
Abstract: you must summarize the context description and state your contributions, in terms of their novelty (For me are not clear).
Thank you for your comment. The abstract was improved highlighting the context and the contributions.
Introduction: You must introduce the most relevant reviews and surveys on the topic (e.g., https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9360490, https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8581571) which should be discussed to explain the paper's contribution. Furthermore, this section may be extended in order to present the state of the art using more directly related references.
Thank you for your comment. The introduction was substantially improved based on your valuable comments. The indicated references were considered as the new references [2] and [34] and, additionally, a new reference [35] was added. The introduction was extended to present the state of the art with direct related references for a better contextualization.
Results: The presented results are not clear to me. For instance: Report the experimental setup in detail to understand its implementation and limitations. A brief comparison with the SoA is required as the one presented in https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9360490 .
Thank you for your comment. The details about the experimental setup were considered aiming to better explain the laboratorial implementation, as well as the limitations.
Conclusions: The conclusion must be improved. The conclusions and results analysis should be oriented not only toward the prototype functionality but also toward a comparison of its results with the state of the art.
Thank you for your comment. The conclusions were improved considering your comment.
Reviewer 2 Report
Dear Authors,
Unfortunately, there is no novelty and interest for readers to read your paper. That's very simple work. Your reduced model is very very weak, and your validation process is unclear.
No parasitci elemens are consiedered.
No control method is discussed.
No application is investigated.
No design process is conducted.
No Loss analyses, stability, and THD are investigated.
Author Response
Reviewer 2
Dear Authors, Unfortunately, there is no novelty and interest for readers to read your paper. That's very simple work. Your reduced model is very very weak, and your validation process is unclear.
No parasitci elemens are consiedered.
No control method is discussed.
No application is investigated.
No design process is conducted.
No Loss analyses, stability, and THD are investigated.
Thank you for your comment. The paper was substantially improved aiming to accomplish with your respected comments. Details about parasitic elements, control method, application, design process, losses, stability, and THD are discussed in this new version of the paper.
Reviewer 3 Report
Development and Experimental Validation of a Reduced-Scale Single-Phase Modular Multilevel Converter
In this paper, the authors focus on the development and experimental validation of a single-phase modular multilevel converter (MMC) based on the use of half-bridge submodules. Regarding the literature, several researchers strived to design new multilevel inverters (MLIs) with less power electronic components by employing diverse combinations of active switches, isolated DC sources, and other passive components. The authors need to highlight their significant contributions clearly in comparison with previous proposed MLIs topologies. Furthermore, I have listed several comments as follows:
1) The grammar needs to be corrected in a number of places.
2) The authors contributions should be highlighted in the Abstract section.
3) The authors need to compare their topology with the recent topologies ( such as PUC converter, PEC9, and PEC13 inverters, and so on) in terms of output voltage level, the number of power switches, number of DC sources, number of Diodes, and DC capacitors.
4) Switching states of the studied inverter topology should be summarized in a table.
5) The THD of load current should be measured and presented under several conditions.
6) The authors should summarize all the system parameters in a table( power system parameters and control scheme parameters)
7) What is the efficiency of the studied multilevel inverter topology?
Author Response
Reviewer 3
In this paper, the authors focus on the development and experimental validation of a single-phase modular multilevel converter (MMC) based on the use of half-bridge submodules. Regarding the literature, several researchers strived to design new multilevel inverters (MLIs) with less power electronic components by employing diverse combinations of active switches, isolated DC sources, and other passive components. The authors need to highlight their significant contributions clearly in comparison with previous proposed MLIs topologies.
Thank you for your comment. The paper was substantially improved aiming to accomplish with your respected comments.
Furthermore, I have listed several comments as follows:
1) The grammar needs to be corrected in a number of places.
Thank you. The grammar was corrected in this new version of the paper.
2) The authors contributions should be highlighted in the Abstract section.
Thank you. The contributions were highlighted in this new version of the paper.
3) The authors need to compare their topology with the recent topologies ( such as PUC converter, PEC9, and PEC13 inverters, and so on) in terms of output voltage level, the number of power switches, number of DC sources, number of Diodes, and DC capacitors.
Thank you. An extensive part of the paper was improved. A new section 2 was added in this revised version aiming to accomplish with your respected comments. New figures, tables, texts and references were added in this revised version of the paper.
4) Switching states of the studied inverter topology should be summarized in a table.
Thank you. An extensive part of the paper was improved aiming to accomplish with your respected comment about the switching states. As you suggested, a new table was added.
5) The THD of load current should be measured and presented under several conditions.
Thank you for your comment. Unfortunately, an analysis about the THD for different conditions of the load was not performed during the development of the work, and thus it is out of the scope of this paper. We hope you can understand the focus of the paper in its current form. We thank you for your valuable comment, and we will perform the analysis of the load current THD in a future work and paper.
6) The authors should summarize all the system parameters in a table( power system parameters and control scheme parameters)
Thank you. As you suggested, new information and a table was added regarding the system parameters in this revised version of the paper.
7) What is the efficiency of the studied multilevel inverter topology?
Thank you. New details about the efficiency were added in this revised version of the paper.
Round 2
Reviewer 1 Report
The paper presents the development of a reduced-scale single-phase modular multilevel converter (MMC), as well as its experimental validation. Dear Authors, The paper was substantially improved in style, clarity, and coherence. However, I don't find anything novel in your paper. That's good implementation work. However, it is not a contribution to the state-of-the-art (SoA). Futhermore, it is difficult to find the papers' contributions, possibly due to the brief presentation and discussion of the directly related to the state-of-the-art (SoA).
Author Response
The paper presents the development of a reduced-scale single-phase modular multilevel converter (MMC), as well as its experimental validation. Dear Authors, The paper was substantially improved in style, clarity, and coherence. However, I don't find anything novel in your paper. That's good implementation work. However, it is not a contribution to the state-of-the-art (SoA). Futhermore, it is difficult to find the papers' contributions, possibly due to the brief presentation and discussion of the directly related to the state-of-the-art (SoA).
Thank you very much for your positive comment. Aiming to accomplish your valuable suggestion, the main contributions of the paper were highlighted in this new version, presenting the contextualization of the work with the state-of-the-art. A new paragraph with the main contributions of the paper was included in the Introduction section.
Reviewer 2 Report
THD in different conditions and Dynamic responses considering accelerating and breaking conditions are needed.
Author Response
THD in different conditions and Dynamic responses considering accelerating and breaking conditions are needed.
Thank you very much for your comment. In order to accomplish your request, a new section 5 was written, where are presented results of the THD of current produced by the railway static converter for different values of operating power, as well as the dynamic response obtained for the current produced by the railway static converter, both for gradual variations and for abrupt variations of the operating power.
Reviewer 3 Report
I would like to thank the authors for their response to my comments. The revision is generally well done, and the presentation has been improved. In my opinion, this manuscript is suitable for publication in its current form.
Author Response
I would like to thank the authors for their response to my comments. The revision is generally well done, and the presentation has been improved. In my opinion, this manuscript is suitable for publication in its current form.
Thank you very much for your positive comments and for the acceptance of our paper.
Round 3
Reviewer 1 Report
The presents the development of a reduced-scale single-phase modular multilevel converter (MMC), as well as its experimental validation. The author states the papers' contributions and describe the experimental procedures and related methodology. My main concern is the paper's novelty, which I believe is limited.
Reviewer 2 Report
Accept in present form
