Circular Economy Aspects of Permanent Magnet Synchronous Reluctance Machine Design for Electric Vehicle Applications: A Review

Round 1

Reviewer 1 Report (Previous Reviewer 4)

Comments and Suggestions for Authors

The authors have revised the manuscript based on the comments, and the manuscript can be considered for publication.

Author Response

Thank you for your positive feedback. 

Reviewer 2 Report (Previous Reviewer 3)

Comments and Suggestions for Authors

The authors have made the necessary revisions as required to make the content of the article more complete and logical. It's acceptable now.

Author Response

Thank you for your positive feedback. 

Reviewer 3 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

The presented main topic of the article regarding the analysis of the environmental impact of materials used in the production of electrical machines of various designs used in micro and small electric vehicles throughout their life and the search for an optimal solution in this regard, while ensuring the required level of performance of these machines, is of a monographic nature, however, it does not apply to specific solutions. The considerations concern the possibility of using various magnetic and winding materials, comparing both their efficiency and environmental impact both during the production process and during operation, as well as the possibility of disposal at the end of the life cycle. The article contains purely theoretical considerations and contains collected statistical data. Given that it contains partial results of research carried out as part of a larger project, it can be published without further corrections.

Author Response

Thank you for your positive feedback. 

Reviewer 4 Report (New Reviewer)

Comments and Suggestions for Authors

In this manuscript, the market penetration possibilities of permanent 

magnet-assisted synchronous reluctance machines for mini and small-segment electric vehicles are reviewed with the consideration of the urban environment and sustainability aspects of the circular economy model. There are several issues as follows.

1. The authors stated that the materials change in the permanent 

magnet-assisted synchronous reluctance machines have siganificant impact on the environment, while the energy conversion efficiency will be reduced, and it also has side effect on the environment, the authors pay more attention on this aspect.

2. Although the circular economy aspect of electric machine of EV is very important, in the reviewer's opinion, the battery may be the most important issues of the circular economy aspect, the life cycle of battery is lower than electric machine, and it is worse for the environment, how do the authors consider this aspect?

Author Response

Dear Reviewer,

Thank you for your time and insightful comments, which helped us improve the quality of the paper.

1. The authors stated that the materials change in the permanent magnet-assisted synchronous reluctance machines have siganificant impact on the environment, while the energy conversion efficiency will be reduced, and it also has side effect on the environment, the authors pay more attention on this aspect.

 We extended the paper from Lines 112-118 to answer this question more directly in the paper. Considering the total cost of the ownership is not new in electrical machine manufacturing, a good example is the design of large power transformers, where the different machine is designed for a water power plant, where high efficiency is important and a photovoltaic plant, which utility factor is low. 

2. Although the circular economy aspect of electric machine of EV is very important, in the reviewer's opinion, the battery may be the most important issues of the circular economy aspect, the life cycle of battery is lower than electric machine, and it is worse for the environment, how do the authors consider this aspect?

Thank you for this question. Battery life and recycling are very important questions. In the paper, we just wrote one paragraph on this topic because we think it needs another review paper. The topic of this paper is related to electrical machine design, not electrical vehicle design. Answering this question is more related to a paper that focuses on electrical vehicles and not this one,, which focuses only on the application of the synchronous reluctance machine in electrical vehicles

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The presented work is of a review nature, but does not contain any significant scientific elements. It may constitute an introduction to further research on this topic, but it does not contain any significant results or conclusions. I believe that this work can be published in a popular science magazine, i.e. with a different profile than Energies

 

The main topic of the article concerns the analysis of the environmental impact of materials used in the production of electric machines of various designs used in micro and small electric vehicles throughout their life and the search for an optimal solution in this regard, while ensuring the required level of performance of these machines. This topic is interesting, but I believe that the presented considerations are preliminary and not supported by the results obtained for specific solutions.

It seems advisable to present in the article several specific designs of various machine designs made using various magnetic and winding materials, to compare both their efficiency and the impact of these materials on the environment both during production and operation, and the possibility of disposal of these machines after the end of their life cycle.

Therefore, I maintain my opinion that in the presented form the article is underdeveloped, not very specific and requires a lot of work to be published in Energies.

 

Author Response

Dear Reviewer,

The authors would like to thank your time and your valueable comments, which helps us to  improve our paper.

Question:

The main topic of the article concerns the analysis of the environmental impact of materials used in the production of electric machines of various designs used in micro and small electric vehicles throughout their life and the search for an optimal solution in this regard, while ensuring the required level of performance of these machines. This topic is interesting, but I believe that the presented considerations are preliminary and not supported by the results obtained for specific solutions.

It seems advisable to present in the article several specific designs of various machine designs made using various magnetic and winding materials, to compare both their efficiency and the impact of these materials on the environment both during production and operation, and the possibility of disposal of these machines after the end of their life cycle.

Therefore, I maintain my opinion that in the presented form the article is underdeveloped, not very specific and requires a lot of work to be published in Energies.

Answer:

The paper has been extensively revised based on the advice of the reviewer. Different electric machine types with different magnets and winding materials has been compared from different point of view. All of the changes highlighted by blue color in the paper.

Reviewer 2 Report

Comments and Suggestions for Authors

     1)     Figure 12 (a) should be specifically noted as Surface PMSM, and line 385 should read” the cross-sections of a Surface PMSM, SynRM, and PMASynRM are shown in Fig. 12.

2)     Strontium-ferrite-based should added in line 396. The sentence should read “Their findings suggest that the strontium-ferrite-based PMASynRM has the poorest dynamic performance in the teste drive cycles.

3)     The comparison should be extended to Vernier PMSM, tangential flux (Spoke type) PMSM and Axial Flux PMSM. 

 

Comments on the Quality of English Language

The language is average and acceptable. 

Author Response

Dear Reviewer,

We would like to thank you for your time and your valuable questions which helped us to improve our paper. All of the changes highlighted by blue color in the paper, while  you can find our point-by-point answers below.

1) Figure 12 (a) should be specifically noted as Surface PMSM, and line 385 should read” the cross-sections of a Surface PMSM, SynRM, and PMASynRM are shown in Fig. 12.

#Answer: The caption of the figure and the mentioned sentence has been revised as advised.

2) Strontium-ferrite-based should added in line 396. The sentence should read “Their findings suggest that the strontium-ferrite-based PMASynRM has the poorest dynamic performance in the teste drive cycles.

#Answer: The sentence has been revised as advised.

3) The comparison should be extended to Vernier PMSM, tangential flux (Spoke type) PMSM and Axial Flux PMSM.

#Answer: The comparison has been extended by different types of electric machines. It was shown that Vernier PMSMs are primarily suitable for in-wheel drive applications, but even then, those have little more advantage over PMSMs. For this reason, and since the in-wheel drive solution for EVs is rare, PMVM is not considered suitable for this research. Breban et al. demonstrated that an STPMSM is fit for retrofitting a light electric vehicle with a fully electric drive based on the requirements set by the L6 European vehicle class; they also proved that the investigated interior PM machines have higher efficiency. Furthermore, Murali et al. compared most of the different rotor configurations of PMSM for EV applications considering SPMSM and IPMSM at 2 kW, 1500 rpm and 4-pole structure. The results show that other types of IPMSM, such as interior, U-shaped, and V-shaped PM, have slightly higher efficiency, considerably lower weight and somewhat lower armature current density. Due to its limitations, STPMSM is unsuitable for this research. Axial Flux Permanent Magnet Synchronous Machines (AFPMSM) are considered to be suitable for electric vehicle applications due to their high torque density, high efficiency, and even flux distribution. Several studies support the EV application, mostly presenting a dual-rotor single-stator topology. Nevertheless, this review focuses on radial flux machines, so axial flux machines are out of scope.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have developed a universal system of criteria for selecting a dump truck model for open pit conditions.The novelty of the proposed system lies in the complex consideration of all known factors to date and criteria of dump truck selectionand the allocation of four groups of criteria: technical, technological, environmental, economic, and organizational.

Organized this review is very comprehensive and clearly shows the shortcomings of the current phase of research as well as suggestions for future development. Recommended for acceptance with minor revisions.

Comments on the Quality of English Language

It is recommended to use less unusual abbreviations.

Author Response

The authors have developed a universal system of criteria for selecting a dump truck model for open pit conditions.The novelty of the proposed system lies in the complex consideration of all known factors to date and criteria of dump truck selection and the allocation of four groups of criteria: technical, technological, environmental, economic, and organizational.

Organized this review is very comprehensive and clearly shows the shortcomings of the current phase of research as well as suggestions for future development. Recommended for acceptance with minor revisions.

#Answer: Thank you for your positive review. The paper has been revised extensively. We are confident it has become more comprehensive.

Reviewer 4 Report

Comments and Suggestions for Authors

This paper provided a systematic summary and analysis of the relationship between passenger car and electric vehicle market penetration, examined the potential for market penetration of permanent magnet assisted synchronous reluctance motors for micro and small electric vehicles, and assessed the potential impact of motor materials on efficiency, taking into account the environmental impact of these materials. The paper provides guidance on how to select the materials to be used in the design process to ensure maximum efficiency and minimise the environmental impact of the materials. However, there are huge flaws in the writing of this paper and huge gaps in the logic between paragraphs, some of the more important issues are listed below: 

1. It is reasonable to suggest in paragraph 102 that the use of recyclable components is directly feasible, and in paragraph 115 to point out that motors designed with highly recyclable materials do not lose too much performance. However, paragraphs 116-119 only point out the impacts of the EU's circular economy strategy based on this, which limits the scope of this paper and should not have been done. 

2. Title 2.1 is the environmental impact of electricity consumption and 2.2 is the 4R strategy in the case of the main components of an electric drivetrain, which do not form a juxtaposition and are illogical. 

3. Section 3.1 compares the different characteristics of mini and small cars, but makes no mention of the characteristics of other models of electric cars. 

4. Chapter 4 focuses on the environmental and ecological impacts of the materials used in electric motors for electric vehicles, but each subsection is written in isolation from each other and is not coherent. For example, section 4.2 is a comparison of rare earths and non-rare earths; section 4.3 is a comparison of aluminium and copper, and there is an inclusive relationship between the two sections. 

5. Chapter 5 is the design of electric motors with circular economy in electric vehicles, but paragraph 467 mentions permanent magnets in section 4.1 again, the logic of the whole article is more confusing, and the reader is more difficult to read.

Author Response

Dear Reviewer,

 We would like to thank you for your time and your valuable questions which helped us to improve our paper. All of the changes highlighted by blue color in the paper, while  you can find our point-by-point answers below:

This paper provided a systematic summary and analysis of the relationship between passenger car and electric vehicle market penetration, examined the potential for market penetration of permanent magnet assisted synchronous reluctance motors for micro and small electric vehicles, and assessed the potential impact of motor materials on efficiency, taking into account the environmental impact of these materials. The paper provides guidance on how to select the materials to be used in the design process to ensure maximum efficiency and minimise the environmental impact of the materials. However, there are huge flaws in the writing of this paper and huge gaps in the logic between paragraphs, some of the more important issues are listed below:

#Answer: The paper has been extensively revised, and the paragraphs have been reordered, rewritten and connected more logically.

1. It is reasonable to suggest in paragraph 102 that the use of recyclable components is directly feasible, and in paragraph 115 to point out that motors designed with highly recyclable materials do not lose too much performance. However, paragraphs 116-119 only point out the impacts of the EU's circular economy strategy based on this, which limits the scope of this paper and should not have been done. 

#Answer: The scope has been extended to China's, Russia's, and India's circular economy efforts to lift the limitations of the paper.

2. Title 2.1 is the environmental impact of electricity consumption and 2.2 is the 4R strategy in the case of the main components of an electric drivetrain, which do not form a juxtaposition and are illogical.

#Answer: The sections have been reordered and rewritten to make the paper more logical. The parts regarding electricity consumption have been shortened and implemented into other paragraphs. The emphasis has been put on the main components of an electric drivetrain.

3. Section 3.1 compares the different characteristics of mini and small cars, but makes no mention of the characteristics of other models of electric cars.

#Answer: The selected machine type (permanent magnet-assisted synchronous reluctance machine) is investigated in academic papers in a power range of 25 kW to 69 kW and a torque range of 83 Nm to 182 Nm at a speed range of 0 rpm to 14000 rpm, that primarily refers to the TELL project's electric vehicle and the FreedomCAR and Vehicle Technologies (FCVT) requirements specified by the U.S. Department of Energy, which covers mini (A) segment electric vehicles with 2WD and one electric machine drivetrain and might be appropriate for small (B) segment electric vehicles with 4WD and two electric machine drivetrain. Because of that, only these two segments are considered. A more detailed explanation has been added to the paper.

4. Chapter 4 focuses on the environmental and ecological impacts of the materials used in electric motors for electric vehicles, but each subsection is written in isolation from each other and is not coherent. For example, section 4.2 is a comparison of rare earths and non-rare earths; section 4.3 is a comparison of aluminium and copper, and there is an inclusive relationship between the two sections. 

#Answer: The subsections has been rewritten and supplemented to highlight the connection between the sections and ensure continuity.

5. Chapter 5 is the design of electric motors with circular economy in electric vehicles, but paragraph 467 mentions permanent magnets in section 4.1 again, the logic of the whole article is more confusing, and the reader is more difficult to read.

#Answer: The back-referencing in the chapter has been corrected to make the paper more logical.