Assessment of the Current for a Non-Linear Power Inductor Including Temperature in DC-DC Converters
Round 1
Reviewer 1 Report
The Authors propose a method for calculating the current profile of a nonlinear inductor operating in a DC/DC converter and subjected to a constant voltage for a given time interval. The authors develop a set of polynomial and differential models for current forecasting. The proposed method allows for improving the electronics design by forecasting the dynamics of designed schematics. The theoretical assumptions are supplemented by simulation. The paper is well-written and easy to perceive. However, I have a set of questions I want to address to the Authors.
1. "Equation (3) can be solved through SPICE simulations". Please, clarify how numerical effects in SPICE simulations may affect the adequacy of nonlinear device modeling. It is known, that SPICE systems rely on numerical methods, which should be chosen with great care while simulating nonlinear systems (see, e.g. the effects of Padé numerical integration in the simulation of nonlinear systems).
2. The second question comes from the first one: "This study implements and compares...the numerical approach... and the SPICE simulations". Actually, both cases are numerical approaches. Please, reformulate this sentence.
3. Can phase space reconstruction techniques be used to obtain the equation of the inductor? Possibly, the integrodifferential model will suit better here.
4. Fig. 4 can be replaced\appended with schematics of the experimental setup. It certainly looks persuasive, but actually adds nothing to the knowledge of the reader.
5. I recommend regrouping\redrawing Fig.5-9 to increase their readability.
6. Possibly, it is of sense to use some difference\error metrics in Fig. 10-13. The shown plots are hard to distinguish by eye.
7. I am a bit wondering about the purpose of Section 8. I believe it can be replaced by a proper conclusion&discussion section, including the comparison of state-of-the-art techniques for identifying nonlinear devices, e.g. structural and parametric identification of memristor, or identification of empirical equations of chaotic circuits from data. The "purpose of the paper" and "Originality" points can painlessly be moved to the introduction.
Minor issues:
Line 34: zone[2,7] - space is missing.
Line 381: of a SMPS varies - I suggest, "of an SMPS varies"
Nevertheless, my overall impression is good. I believe the reviewed paper is highly relevant to the Electronics journal and can be a great contribution after some revisions.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
1. It is well known that the change in inductance value seems to cause fluctuations in the output of the converter;
2. The working temperature is related to the size of the inductance value, and compensation control is required;
3. The manuscript mainly works on experimental testing, and its academic value is not high.
More comments are shown below FYI. 1. What is the main question addressed by the research? It just tells us the common sense. 2. Do you consider the topic original or relevant in the field? Does it address a specific gap in the field? The topic is relevant with Electronics and topic related. 3. What does it add to the subject area compared with other published material? The research contents is less and should improve. 4. What specific improvements should the authors consider regarding the methodology? What further controls should be considered? More theory and analyzig are necessary, especially with the protype and the working condition, i.e., load, sampling frequency, etc. 5. Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? No. 6. Are the references appropriate? Yes 7. Please include any additional comments on the tables and figures. It is fair.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors provide an attempt to model a non-linear inductor, but the first criticism is that the analysis is not supported by a strong mathematical analysis. Only well-known and consolidated expressions are presented in the manuscript.
Another important issue is that there is no description of the physical implementation of nonlinear inductors. What kind of magnetic material is used? This choice will affect the behavior of the inductor significantly?
The result shown in Fig. 5 does not seem relevant to me. It is obvious that increasing D in a boost converter will lead to a higher output voltage up to a certain point depending on the inductor series resistance. Besides, increasing D will lead to an increase in the inductor current ripple. Anyway, the operation in the saturation region will depend on several practical conditions, but the test is not clearly explained. For instance, is the output voltage constant?
Are the values shown in Table 1 correct? How one can measure a negative inductance in practice?
The authors mention that the harmonic spectrum varies as the operating temperature also does. However, there is no Fourier analysis to demonstrate it. How is it possible to incorporate this effect into the model in numerical terms? Besides, how did the authors control the inductor temperature in a real scenario?
Once again, I insist that the mathematical analysis is insufficient, whereas only eight equations are presented. Overall, I am not convinced that the present analysis can be extended to any dc-dc converter.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear authors! Thank you for providing a revised version of your manuscript. The paper was significantly improved during the revision process, and therefore I can warmly recommend it for publication. I wish the Authors all the luck and success in their further studies.
Reviewer 3 Report
The authors could address most of my requests comprehensively. As a final advice, I will only ask them to replace blurred figures with high-quality vector graphics (Figs. 1, 2, 3, and so on) and proofread the manuscript to eliminate most typos and inconsistencies.
