Review Reports

Round 1

Reviewer 1 Report

General Comments

There are some mistakes given as follows: 

-In line 329, a word is missing after of

-In line 19 i.e. The proposed modulation algorithm is implemented for FT2LI is implemented in MATLAB/Simulink Platform.... you can remove the use of "is implemented" before "for FT2LI..."

-In line 117 correct the degree symbol after 60

-Reference mentioned on [32] is not cited

Other considerations:

-Provide better explanation of table 6 and 7 as to how your results are better than others

-Literature review could have been more extensive, Research lacks review of switching schemes for SVPWM techniques for other inverters 

-Provide an understanding and comprehensive overview of inverters and F type inverter for readers that are less familiar with the topic so they can grasp the concept before delving into specific details.

-You may also consider including figure of switching time representation of other phases in subsection 1 shown in figure 4

-it would be better to show calculation/derivation of dwell time (eq 5, 6, 7) in more detail for at least 1 subsection or may provide reference that readers may look.

-prototype pics fabricated in lab should be attached for transparency

-Finally, please mention the application areas of the proposed inverter

Moderate English language editing is required. 

Author Response

Please see response in the attached file

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper is well written and prepared. The authors should refine the conclusions a little bit. The contribution of the method to the existing industrial should be emphasized

Author Response

Dear Reviewer,

Thank you for your valuable comments. As per the reviewer comments, the conclusion has been enhanced in the revised manuscript. 

Reviewer 3 Report

The manuscript presents a new proposal for the SVPWM technique based on segment reduction for a three-level ZSI. For implementation, the author presents a well-elaborated simulation with very interesting results. In order to validate the results, the author also presents an experimental configuration of the SPARTAN 6 FPGA controller to generate the port signal for switches.

In short, the manuscript was well prepared, presenting a good theme and of great interest to the scientific community, as well as presenting very promising results. However, I leave some recommendations in order to improve the manuscript and only then accept the manuscript.

 

1st The Figures are all in bold letters. I think you should take the bold out of the letters.

2nd Table 2, must go down and fit all of it on one page.

3rd Formula 2 does not need to be in bold. It should get better.

4th The letters in Figure 4 and Figure 6 are not clear. I think it should expand.

5th Table 7 should go down and fit all of it on one page.

6th The formatting of figure 7 is not good, it should be improved

7th Figure 12, presents the experimental result using SVPWM, and therefore it is of great importance. The same Figure is not clear (the letters), so I strongly recommend improving.

8th I see that it presents the results of the experimental configuration. Since this is a fundamental point of the manuscript, I think it would be good to present an image of the experiment (prototype). Therefore, I strongly recommend submitting an image of the experimental setup (prototype).

Author Response

Please see attached response

Author Response File: Author Response.pdf

Reviewer 4 Report

In this paper the authors introduce improvement of a segment reduction based SVPWM technique for multilevel converters in the meaning of reducing the THD, switch losses and switching transition count. After detailed analysis of a profile of switching state transitions in simulation, the paper brings the results of experimental testing of the proposed technique using SPARTAN 6 FPGA controller which prove the stated paper contribution.

A question: A simulation of what was conducted to evaluate efficiency of FT2LI, row 329?

The English writing style is good, but there are few grammar mistakes and typographical errors.

Author Response

# Reply to reviewer -4: Dear reviewer, Thank you so much for your expert comments and suggestions to improve the quality of the manuscript. We have made all the requested changes and added the new information, as given below in our response to your individual comments. Note: The corrections in the revised manuscript are depicted in yellow colour text.

Qn.1. A simulation of what was conducted to evaluate efficiency of FT2LI, row 329?

#Answer to reviewer:

Dear Reviewer, Thank you for your valuable comments. The line 329 is a typographical error made while writing the paper. As per the reviewer instruction that error has been corrected and shifted in line 338 in the manuscript.

Reviewer 5 Report

 

The paper presents a novel approach to space vector pulse width modulation (SVPWM) used to drive F-type three-level inverter (FT2LI). The proposed modulation technique revisits the conventional SVPWM by eliminating redundant switches pattern to avoid unnecessary switching energy and improve the converter efficiency. In addition, the proposed segment reduction SVPWM provides better overall THD performance and optimize high-order harmonics since their cluster is mainly distributed around the selected switching frequency compared to various carrier-based (CB) PWM. The overall steps behind the proposed approach are clearly explained and detailed. However, there are few points which need to be taken into consideration:  

· The proposed SVPWM is only compared to CBPWM but is not compared to the conventional SVPWM.

· In Table 5 could you please clarify what the points i), ii), iii), iv) refer to?

· In Figure. 6. (b): does Tx/2 refer to the total sum of eliminated segments duration? If yes, please mention it in order not to confuse the reader. If no, please provide more clarification.

· In Figure. 7. (a) what is the explicit value of Tx/2. While in figure (b) are you sure that T2/2 is the duration of the segment HOL.

· Same remarque for both Figures 8 and 9.

· In Section 4 line 329: “extensive simulation of were conducted” is there a missing word in this sentence?

· Section 5 line 247: it is “VSI” and not “ZSI”.  

Author Response

Please find attached response

Author Response File: Author Response.pdf

Reviewer 6 Report

The manuscript is interesting and in line with the scientific art. The authors presented a scientifically improved spatial vector pulse width modulation (SVPWM) with the possibility of practical use in low-voltage T-NPC inverter applications. Despite the well-done scientific work, the authors should correct in the submitted manuscript:

1. Include the "Discussion" section and clearly analyze the obtained simulation results

2. Conclusions should be more developed and discussed in more detail

3. Enlarge the review of the literature because with such a complex problem, 32 publications are not enough

Author Response

# Reply to reviewer -6: Dear reviewer, Thank you so much for your expert comments and suggestions to improve the quality of the manuscript. We have made all the requested changes and added the new information, as given below in our response to your individual comments. Note: The corrections in the revised manuscript are depicted in yellow colour text.

Qn.1. Include the "Discussion" section and clearly analyze the obtained simulation results

#Answer to reviewer:

Dear Reviewer, Thank you for your valuable suggestion. Under section number 4.1 the simulation results obtained, are well analysed, compared with multicarrier PWM & conventional SVPWM and tabulated in Table 7 &Table 8. In section number 4.2 the experiment is conducted on the proposed prototype FT2LI using three segment reduction algorithm and the results obtained are compared with multicarrier PWM for an amplitude modulation index of ma= 0.8 and frequency modulation index of mf=145. The FFT plots depicted by Figure 14 highlight the observed experimental results.

Qn.2. Conclusions should be more developed and discussed in more detail

#Answer to reviewer:

Dear Reviewer, Thank you for your valuable suggestion. As suggested by the reviewer, the conclusion has been rewritten to highlight the importance of the objective.

Qn.3. Enlarge the review of the literature because with such a complex problem, 32 publications are not enough

#Answer to reviewer:

Dear Reviewer, Thank you for your valuable suggestion. As per the reviewer comments, a few references have been added to the revised manuscript.

Round 2

Reviewer 3 Report

Dear author, after the changes provided and the review carried out, I think the manuscript is better. Therefore, I am accepting the manuscript.

Reviewer 6 Report

I am not qestions end suggestions.