Design and Optimisation of a 5 MW Permanent Magnet Vernier Motor for Podded Ship Propulsion

Round 1

Reviewer 1 Report

*The authors should state the main finding of their work in the abstract section.

* What are the practical applications of the considered problem?

* More physical descriptions should be added to the results and discussion section.

* A mathematical description of the solution methodology should be provided briefly.

* More physical justification is needed

* The novelty of the work is not clear. Please describe.

* There are some typing errors in the manuscript. Check the paper again for any possible misprints..

* In the Abstract section, you should describe your work and contribution more clearly than what they were in the background of the research. Currently, it is hard to know the main content and results of this article from the Abstract.

* The language of the paper needs to be improved.

* In the introduction, the development of an argument to present the problem is weak. Discussion on why this study is important is missing. The introduction section is poorly organized.

Introduction ignored important contributions in this research area.  Please at least add 5 more references in 2022 and 2023.

The language of the paper needs to be improved.

Author Response

Dear reviewer 1,

The authors would like to cordially appreciate reviewer for his/her time and effort to review our manuscript. Thank you for the hopeful, encouraging viewpoint and valuable comments on our manuscript. It surely improves the quality of the paper. We have modified the manuscript accordingly, and the detailed corrections are listed below point by point. It should be noted, for clear addressing the modification, all corresponding modifications made in the text of the manuscript are highlighted as follows;

Yellow color for only reviewer #1.

Grey color for the common question of reviewers.

In the following, the authors' answers and the list of changes are presented according to the comments. The authors hope that these corrections will satisfy the respected reviewer.

Sincerely yours,

Nima Arish

Corresponding Author

Stellenbosch University, South Africa

Author Response File: Author Response.pdf

Reviewer 2 Report

The author studied on Design and optimization of 5 MW permanent magnet Vernier motor for POD ship propulsion. However, it is an interesting study it needs some revisions as below;

1.    The POD in the title must be written openly.

2.    The abstract is seen a little long. It can be shortened.

3.    Figure 1 and 2 must be shown in another chapter about POD. Not in introduction

4.    There is required a last paragraph in introduction part to define the novelty and summary of this study.

5.    The manuscript needs a nomenclature part to define the parameters.

6.    Where did you obtain Figure 4, 5 and 6?  There can be some references if obtained in literature.

7.    Figure 13 a, b, c, not seen good. It must be explained.

8.    There is required a FEM analyses software.

9.    There are a lot of figure for a research of papers. Some of them removed or must be shown with subfigures. For example, figure 19.

10. There is required a graphical abstract to be defined the paper more detailed.

11.The references can be increased with more related studies.

12.The typo and grammar errors must be checked.

13.There is no any information about Table 5. It must be explained in text.

14.There is not any experimental part to be verify the ideas.

Author Response

Dear reviewer 2,

The authors would like to cordially appreciate reviewer for his/her time and effort to review our manuscript. Thank you for the hopeful, encouraging viewpoint and valuable comments on our manuscript. It surely improves the quality of the paper. We have modified the manuscript accordingly, and the detailed corrections are listed below point by point. It should be noted, for clear addressing the modification, all corresponding modifications made in the text of the manuscript are highlighted as follows;

Yellow color for only reviewer #2

Grey color for common question of reviewers.

In the following, the authors' answers and the list of changes are presented according to the comments. The authors hope that these corrections will satisfy the respected reviewer.

Sincerely yours,

Nima Arish

Corresponding Author

Stellenbosch University, South Africa

Author Response File: Author Response.pdf

Reviewer 3 Report

1.      The abstract is loose and generic. No motivation, numerical findings, and contributions are mentioned. The abstract should be rewritten in a more concise and digested way.

2.      What do you mean by the thermal loading?

3.      Many of the references are not recent and new research on machine design and motor optimization has been carried out in the last 5 years. Please, consider the following references:

-        Wu, W., Xu, L., & Liu, B. (2021). Design, Analysis, and Optimization of Permanent Magnet Vernier Machines Considering Rotor Losses. Energies, 15(4), 1502. https://doi.org/10.3390/en15041502

-        L. Vadamodala et al., "Comparison of Electric Machine Types for Electrically Driven Engine Accessories Using Multiphysics Simulation Tools," in IEEE Transactions on Industry Applications, vol. 57, no. 2, pp. 1399-1410, March-April 2021, doi: 10.1109/TIA.2020.3048095.

4.      What is the optimized air gap distance in "mm"? Have you considered it when optimizing the power factor and loss?

5.      Table 5 compares all the parameters and design variables. However, no speed (base speed) is mentioned. The optimization should map the torque-speed characteristics showing the efficiency of every operating point.

6.      The mapping presented in Fig. 18 is good but the resolution of the simulations is poor. I believe that more points should be considered and therefore, the efficiency would change at many operating points. Please, refer to the suggested reference in the 3^rd comment.   

  English language in most of the paragraphs needs polish.

Author Response

Dear reviewer 3,

The authors would like to cordially appreciate reviewer for his/her time and effort to review our manuscript. Thank you for the hopeful, encouraging viewpoint and valuable comments on our manuscript. It surely improves the quality of the paper. We have modified the manuscript accordingly, and the detailed corrections are listed below point by point. It should be noted, for clear addressing the modification, all corresponding modifications made in the text of the manuscript are highlighted as follows;

Yellow color for only reviewer #3

Grey color for common question of reviewers.

In the following, the authors' answers and the list of changes are presented according to the comments. The authors hope that these corrections will satisfy the respected reviewer.

Sincerely yours,

Nima Arish

Corresponding Author

Stellenbosch University, South Africa

Author Response File: Author Response.pdf

Reviewer 4 Report

The manuscript presents research related to improving the performance of electrical propulsion systems in the marine sector based on the optimal design of a Permanent Magnet Vernier Motor (PMVM). In this regard, PMVMs are categorized into three distinct groups (Type-A, Type-B and Type-C) according to their gear ratio (Gr) range. Several PMVM models from each group are designed, optimized and compared on various parameters with classical PMSM engines at a power level of 5 MW, which is relevant for propulsion of a POD ship. For optimization purposes, an appropriate objective function is formulated, and various constraints related to motor dimensions, allowable current density, efficiency, and other design considerations. On this basis, conclusions and recommendations are made for the practical implementation of PMVM for different needs. The manuscript is on a very topical subject and has great potential for development. My main observations and comments are as follows:

- it would be useful for the authors to comment on the disadvantages of PMVM in addition to the advantages in the conclusion section. In this way, a complete picture of its qualities, capabilities and application limitations will be obtained;

- I recommend commenting on the economic aspect of the research in the sense of making an assessment of the effect of using PMVM to improve the characteristics of ships and, accordingly, reduced operating costs;

- I recommend adding a discussion section to systematize and analyze the numerous results of numerical experiments and formulate guidelines for research development.

Author Response

Dear reviewer 4,

The authors would like to cordially appreciate reviewer for his/her time and effort to review our manuscript. Thank you for the hopeful, encouraging viewpoint and valuable comments on our manuscript. It surely improves the quality of the paper. We have modified the manuscript accordingly, and the detailed corrections are listed below point by point. It should be noted, for clear addressing the modification, all corresponding modifications made in the text of the manuscript are highlighted as follows;

Yellow color for only reviewer #4

Grey color for common question of reviewers.

In the following, the authors' answers and the list of changes are presented according to the comments. The authors hope that these corrections will satisfy the respected reviewer.

Sincerely yours,

Nima Arish

Corresponding Author

Stellenbosch University, South Africa

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Accept

Author Response

Thank you so much for your time and careful consideration in improving the quality of our paper.

Reviewer 2 Report

The author studied on design and optimization of 5 MW permanent magnet Vernier motor for POD ship propulsion. Although some of the revisions are made some of them as below not satisfied yet;

1.    There is required a last paragraph in introduction part to define the novelty and summary of this study.  All the explanation must be given in manuscript.

2.    The manuscript needs a nomenclature part to define the parameters. I don’t agree with the answer.

3.    Where did you obtain Figure 4, 5 and 6?  There can be some references if obtained in literature.

4.    In figure a, b, c, captions not seen good.  They must be cantered.

5.    There is required a FEM analyses software example to verify the study.

6.    There are a lot of figure for a research of papers. Some of them removed or must be shown with subfigures. For example, figure 19.  It is not seen removed in manuscript. The aim must be reducing the total figure number.  

7.     There is required a graphical abstract to be defined the paper more detailed.  Not satisfied.

8.    The table 5 can be given in discussion part.

Author Response

 Dear Reviewer 2,

The authors would like to cordially appreciate Reviewer for his/her time and effort to review our manuscript. Thank you for the hopeful, encouraging viewpoint and valuable comments on our manuscript. It surely improves the quality of the paper. We have modified the manuscript accordingly, and the detailed corrections are listed below point by point. It should be noted, for clear addressing the modification, all corresponding modifications made in the text of the manuscript are highlighted as follows;

yellow color for only reviewer #2.

In the following, the authors' answers and the list of changes are presented according to the comments. The authors hope that these corrections will satisfy the respected reviewer.

Sincerely yours,

Nima Arish

Corresponding Author

Stellenbosch University, South Africa

Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for addressing my comments

Author Response

Thank you so much for your time and careful consideration in improving the quality of our paper.

Reviewer 4 Report

The authors have responded to my remarks and comments. I have no further comments.

Author Response

Thank you so much for your time and careful consideration in improving the quality of our paper.