The ZVS Class E/F3 Inverter Using Piezoelectric Transformers for Energy Extraction
, M. Saad Bin Arif 2,*, Abdul Rauf Bhatti 3, Ahmed Al Mansur 1, Md. Hasan Maruf 1 and ASM Shihavuddin 1Round 1
Reviewer 1 Report
The article gives the values of the parameters of the constructed system.What measurement techniques do you use?
How were the parameters of the transistor modeled?
Is it possible to estimate the efficiency of the system at this stage of the research?
Author Response
Comment: The article gives the values of the parameters of the constructed system.
Response : Authors are thankful to the reviewer for the valuable comments and suggestions. In the following section reposes to the individual comments were discussed.
Point 1: - What measurement techniques do you use?
Response 1: Thanks for your comment. The measurement techniques are described in Section 3.
Point 2: How were the parameters of the transistor modelled?
Response 2: Thanks for your comment. For simulation, the transistor realistic model is used for LTspice simulation. The transistor is selected based on the voltage and current rating in the circuit.
Point 3: Is it possible to estimate the efficiency of the system at this stage of the research?
Response 3: Thanks for your valuable comment. The authors did not determine the efficiency at this stage. However, the efficiency measurement will be included in the upcoming and extended version of this work. The later will also incorporate a comparative study with the classic inverter circuits.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The subject is interesting.
Nevertheless, the novelty is not well described in the abstract. In the first sentence, the use of EFn or class Phi2 topology is well known to reduce the peak voltage on the switch compare to class E topology then the word “proposed” related to “In this paper” introduces confusion. If the novelty is the use of piezoelectric transformer, that should be written clearly.
I don’t understand the “conceptual energy extraction from PT”, here the power is not extracted from the PT but get on the input voltage Vin and transferred to the output, PT being only a transient storage. That should be clarified.
The paper shows that PT can replace the “primary resonant tank” or the “auxiliary resonant tank” thanks to simulation and measurement. Nevertheless, we do not know why we do it; there is no reference in the state of the art about it. Furthermore, the paper does not make any comparisons between the conventional EF3 converter and the PT based one, for example in term of efficiency or power density.
The paper contains very little text and the explanations are missing or unclear. Some parts should be rewriting, for exemple between lines 46 to 69. A careful proofreading would have been helpful before the review, some sentences having no sense or are a repeat or containing big typography mistake.
Some detailed comments:
Line 56: “when the switch S1 is in the ON position, … Cin decreases to zero”, “forced to zero” should be better than “decreases to zero”. But it not in agreement with ZVS operation, I think the description is not correct and should be detailed and improved.
Line 59: “When S1 closes”, I think it is “When S1 opens” in the context
The electrical perameters Vs1, Iout, Iin, Ir … should be placed on the electrical schematics figures.
Line 95: why choosing a so poor quality factor of Q=0,707? It necessary induces large losses.
Fig. 3: specify that the transformer is magnetic
Some figures or tables should be reduced in size and better organized compare to the text.
TABLE II: the correspondence of the parameters with the electrical schema should be given.
Line 121: the senence “the results from LTSPICE simulation circuit are demonstrated“ has no sens. It would be better to explain what is demonstrated and how it is demonstrated.
Line 122: I suppose it is Fig. 5(a) and not Fig. 5(b)
Line 129: “This is how the output power is determined- “ ??
Fig. 9 : (c) doesn’t exist
Table V :Some difference exist betwen simulation and experiment and should be explained. The power and the efficiency should be also noticed.
Line 167 to 169 in the conclusion : What data supports the conclusion « A compact, high-efficiency, low-power inverter can be created by replacing the traditional magnetic components in resonant networks with energy extracted from PT. » ?
Author Response
Responses to the reviewer's comments are attached as a pdf file.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors, your paper proposes an enhanced class E converter to reduce the high peak switch voltage issue in class E inverters, and improve stability and load regulation. However, there are issues in the presentation of the paper.
- Language editing. The article is not well written, has poor explanations, and has many grammatical and technical writing mistakes. Please revise it in deep and check the whole text.
- Abstract. The advantages of the method are not well explained. Please, redo this part to improve the paper.
-Introduction. There are few references to introduce the study. I’ve found that quite short. Please, use more recent references to describe state-of-the-art, the gap in the knowledge, and the purpose of the study.
I believe that the inverter topology can be provided in a separate section and described in a more interesting way, with figures appearing near the text.
The figures are very small and the equations don’t follow the journal template.
The structure of the paper should be mentioned briefly in the introduction.
- Section 2. I have found this part badly written. Readers need to understand it in a more direct way. The figures should be larger, and the equation about the calculations should be presented and explained in a better way to explain the calculation of the parameters in both cases, as a primary or auxiliary resonant tank.
- Section 3. This part of the article is very confusing and hard to follow. I recommend rewriting it all in a better and more direct way to follow and understand the obtained results and understand what is the contribution.
Figures should be larger.
There is little information about the prototype setup.
How the parameters of the circuit in Tables 3 and 4 have been selected?
The figure shown should be more clear, and better resolution.
- Conclusions: Please improve this part of the paper. I’ve found it short.
Author Response
The authors are thankful to the reviewers for their valuable comments and suggestions. The response to the comments is attached as a pdf file.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thank you for the improvement of the paper. However, efficiency versus power output is still missing and needs to be added to make the article complete enough to be published.
Some remaining points:
Point 3 : The electrical perameters Vs1, Iout, Iin, Ir … should be placed on the electrical schematics figures.
Not done in the new version :
Point 4: Line 95: why choosing a so poor quality factor of Q=0,707? It necessary induces large losses.
Your answer : A large Q would require a large inductance. Apparently, the PT used for experimental testing does not have the required inductance to emulate a larger Q.
But Q=0.707 is in the « Table I. DESIGN SPECIFICATIONS » and not in « TABLE II. CHARACTERISTIC COMPONENT VALUES OF PT » where Q=281.3 ?!!
Point 12: Table V: Some difference exist betwen simulation and experiment and should be explained. The power and the efficiency should be also noticed.
The efficiency is not given. I don’t know why? It doesn't seem very difficult to measure! This one have to be given in the final version otherwise the paper loses a lot of interest for the reader.
Author Response
Responses to the reviewer 2 comments
Comment: Thank you for the improvement of the paper. However, efficiency versus power output is still missing and needs to be added to make the article complete enough to be published.
Response: Authors are thankful to the reviewer for the valuable comments and suggestions. In the following section reposes to the individual points raised by the reviewer were discussed.
Point 3: - The electrical perameters Vs1, Iout, Iin, Ir … should be placed on the electrical schematics figures.
Response: Thanks again for your valuable feedback for improving the paper. We have added the parameter names in the revised manuscript in Fig. 6 and 9.
Point 4: Line 95: why choosing a so poor quality factor of Q=0,707? It necessary induces large losses.
Response : A large Q would require a large inductance. Apparently, the PT used for experimental testing does not have the required inductance to emulate a larger Q.
Point 12: Table V: Some difference exist betwen simulation and experiment and should be explained. The power and the efficiency should be also noticed.
The efficiency is not given. I don’t know why? It doesn't seem very difficult to measure! This one has to be given in the final version otherwise the paper loses a lot of interest for the reader.
Response: Many thanks for the feedback. We have added the efficiency and power curve in the revised manuscript in Fig. 11.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dears, to me the paper is ok now. However I have the following minor questions
1- Increase Figs. 1, 5, 7, 10
2- Increase Figs. 2, 3, 4, 8 and improve their quality
Author Response
Response to Reviewer 3 Comments
Overall Comment: Dears, to me the paper is ok now. However I have the following minor questions
Response: Authors are thankful to the reviewer for the appreciation and revised the manuscript by addressing the suggested corrections.
Point 1: - Increase Figs. 1, 5, 7, 10
Response: Thanks for your comment. We have increased the size of Fig. 1, 5, 7, and 10 as suggested.
Point 2: Increase Figs. 2, 3, 4, 8 and improve their quality
Response : The manuscript is revised with improved quality and proper sizing of the figures as suggested.
Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
Thank you for improving the content of the paper.
I think Figure 11 is a measured efficiency, and not a simulated efficiency. It should be clearly stated in the text.
Otherwise, the document now seems to me to be sufficiently complete and consistent.
Author Response
Response to Reviewer 2 Comments
General comment: Thank you for improving the content of the paper.
Point 1: I think Figure 11 is a measured efficiency, and not a simulated efficiency. It should be clearly stated in the text.
Otherwise, the document now seems to me to be sufficiently complete and consistent.
Response 1: Thank you for your valuable feedback. We have changed the figure caption and added the information in the body text as suggested. Also, the measured efficiency is stated in the abstract.
Author Response File: Author Response.pdf
