Enhancement and Performance Analysis for Modified 12 Sector-Based Direct Torque Control of AC Motors: Experimental Validation

Round 1

Reviewer 1 Report

The parameters of the motor in Appendix A Table A1 have big problems. First, the AC motor has 2 pair poles, and the rated frequency is 50Hz, while rated speed is 282 rad/sec. Second, the risistance of the motor has 45.83 Ω, it is too large. Third,  stator flux and rotor flux is too large compared with the rated power 0.25kW.  In addtion, for a proper AC motor, the rated power 0.25kW can not achieve 282rad/sed and 1.76Nm at the same time.  Based on above problems, I think this paper has big problems.

Author Response

Thank you for the comment.

Author Response File: Author Response.pdf

Reviewer 2 Report

In the paper, a modified twelve sector-based DTC is proposed to improve the AC motor drive. The proposed drive system offers several contributions, such as very low torque ripple reduction, faster dynamics, and reduced stator flux ripples compared to the classical DTC.

The authors present an analytical method of creating a voltage vector switching table for each of the 12 sectors. Then they carry out simulation studies of the results of applying the proposed method. Finally, the results of the simulation analysis are confirmed by experimental research. Research results are well documented. The proposed method has many advantages over the classical method.

Well written article.

Author Response

The authors appreciate your valuable comments and expertise. The paper quality is really improved based on your constructive comments.

Author Response File: Author Response.pdf

Reviewer 3 Report

In reviewing this work, it should be noted that the article was developed by the authors at a very high scientific level, making a significant contribution both in terms of the choice of technical approach and to the scientific research presented. The research and simulation tests performed, including the experimental validation carried out (Chapter 5), make a key contribution to the deepening of knowledge not only in electrical engineering, but also in related fields in the multidisciplinary aspect concerning power systems, including in particular both electronics and knowledge related to advanced power electronics, as well as electrical machines in general. 

In terms of research, the work is characterized by an interesting novel idea in solving the research problem considering the challenges of the switching table, based on the analysis of enhancement the 12 sectors direct torque control algorithm (DTC) of AC motor drives. 

Its new contribution is both the technical approach itself in terms of the methods used and, above all, the analytical development of the switching table for highlighting the proposed method not only through the simulation studies performed, but also in the field of confirming the results obtained based on a practical experiment based on a dSPACE platform, including through the use of the dSPACE DS1103 digital processing card. 

The above assessment in the aspect of the proposed approach, made by the authors of this manuscript, is evidenced, among others, by the conducted critical analysis of the literature on the subject of research in the light of existing solutions in the current state of knowledge, as well as the analysis of the presented solution, performed in a thorough, coherent and at the same time accurate manner, skillfully supported by the mathematical apparatus used for the presentation of the operation of the DTC algorithm and the applied research methods. This is very important from the point of view of existing knowledge, as evidenced by the results of the analysis carried out by the authors in terms of the adopted strategy to solve the research problem. 

The choice of the proposed methodology was supported both by an in-depth analysis of the specific phenomena occurring, including in the aspect of the scientific problem being solved in terms of the design of a switching table with a direct impact on the performance of the motor drive, and by the research carried out in this regard, i.e. both through tabular summaries (Table 1-3) and graphical depictions (Figs. 1-7), including a block diagram of the classical DTC system, a map of 12 sectors and a block diagram of the proposed DTC method (Figs. 1-3), the effect of vectors on the main parameters of the motor (Figs. 4-7), as well as the simulations performed, illustrated in Figs. 8-19 (analytical method) and Figs. 20-26 (experimental validation) of the results obtained, which allowed us to present important insights and formulate practical conclusions in the final part of this work.

During the review of this manuscript, with the exception of minor editing errors and some inaccuracies observed in the presented article, no other significant shortcomings were found, having a significant impact on the level and quality of the evaluated work.

Abstract: 

According to the recommendations of reputable publishers and journals (IEEE TTE, IEEE Access, Wiley and Sons), as well as MDPI, the abstract of the manuscript, article, paper, etc., should refer to its key elements, e.g. introduction (reference to the subject of research), statement of the explicit purpose of the work, approximation/statement of the potential solution to the problem/methods used, as well as reference, based on the conducted research (e.g. tests, simulations, mathematical model, experiment), to the formulation of significant observations and final conclusions (final part of the work). 

An exemplary option to address the results of the research in terms of final conclusions can be formulated as follows: 

Based on the critical analysis of the research literature, the research investigations carried out (study, model, simulation tests), supported by the mathematical apparatus used, the model created, and the analysis and validation of the results obtained, conclusions and observations were formulated, reflected in practical applications. 

The abstract should not exceed 200 words, in this paper there are 165 of them. In my opinion, the abstract of this paper lacks explicit reference to both the predicted research results obtained and the observations and conclusions formulated (part of the conclusion of the paper) in the context of the solution applied and the work results obtained. 

Inaccuracies in the form of editorial and methodological errors observed in the abstract section of this manuscript: 

1. No statement of the explicit purpose of the paper.
2. It is not advisable to explain abbreviations in the abstract, as was done in this paper for DTC. It should be explained later in the paper, such as in the introduction.
3. In my opinion, the abstract does not clearly present both the purpose of the work and the expected results in terms of presenting important insights and formulating final conclusions (the final part of the work), especially with regard to practical applications. 

Minor inaccuracies noted in the rest of the work: 

1. Using sentences that are too short in the article, both in the abstract and in the rest of the paper, such as Nevertheless ... (abstract); p. 1 for This type is ... ; p. 2 for However, difficulties ... , or for This method was characterized by simplicity. However, the steady state characteristics were not fully investigated, etc. Please check the entire paper in this regard. 
2. In reviewing this article, I observed a lack of explanation of some abbreviations, e.g. FOC, PWM, DTC-VC, DSP, THD, PMSM, SiC MOSFETS, PMSG, DACs, etc. In addition, the authors have duplicated the explanation of the abbreviation DTS, i.e. in the abstract and in the introduction section. Please check the entire paper in this regard. Regarding the explanation of abbreviations, it should be noted that this paper will not be used only by experts, so all abbreviations and designations used should be explained in the paper. 
3. With the exception of the duplication of [18] on page 2 and [6] on page 4, the correct order of literature references used has been maintained. 
4. From the methodological aspect, in my opinion, it is not recommended to present a figure, table, or formulas in the concluding part of a chapter/subchapter or point/subpoint, as has been done in this article, such as Table 1 on page 4; Table 2 on page 11; Figure 19 on page 16 in Chapter 4; Figure 26 on page 20 in Chapter 5, or Table 3 (Chapter 6). Please make the appropriate correction in this regard. 
5. Other editing errors in the use of punctuation marks, or grammatical errors, e.g., p. 1 for DSP In the Loop ... (introduction); p. 2 for Fast Torque Control ... ; p. 3 for γ[26]; Table 1 and Table 2 (use of Bold font in the text of the paper) on p. 4 and 20, respectively; p. 4 for ... Figure 2 The ... and use of Method; obseved on p. 6; variaiation on p. 9, or N.m designation, etc. Please check your entire work in this regard and make the appropriate corrections. 
6.  Failure to maintain unambiguous notation, e.g., 5(rad/sec), 0.1rad/sec, 0.12 rad/sec, and 0.24 rad/sec, on pages 14 and 15, respectively. Please check the entire paper in this regard. 
7. In the conclusion of this paper in the aspect of citing important insights and formulating final conclusions reflected in practical applications, the conclusions and key observations are supported by the research results obtained, however, in my opinion, for methodological reasons, they should not be terminated in the form of a bullet point, as was done in this article. 
8. Minor errors in the list of literature attached at the end of the work, regarding editing and use of punctuation marks, as well as in terms of clarity of writing, e.g., items 2, 10, 14, 20-22, 26-27 and 29 cited on pages 22-23, respectively. In addition, according to me, the information contained in the attached Appendices A and B in the form of Table A1 and motor constants can be included in the main part of the paper.  

Strong aspects:

Technical approach, the idea of solving the problem and its explanation, analysis of the research results obtained, supported by the formulation of final conclusions, relevance in terms of the methods used and ability to use them.

Weak aspects:

Minor shortcomings that have no significant impact on the quality of the reviewed work, i.e. editing errors and poor quality of the methodological part of the abstract.

Recommended changes:

Regardless of the Editorial Board's decision, at this stage of the work I would recommend that the authors of this paper correct the above (weak points).

Author Response

The authors appreciate your valuable comments and expertise. The paper quality is really improved based on your constructive comments.

Author Response File: Author Response.pdf