DC Voltage Source Based on a Battery of Supercapacitors with a Regulator in the Form of an Isolated Boost LCC Resonant Converter

Round 1

Reviewer 1 Report

The article presents a study focused on developing an electric double layer capacitor (EDLC) bank with a constant voltage output using a boost converter and an inductor/capacitor/capacitor (LCC) resonance converter. This innovative approach addresses the output voltage decline issue in supercapacitors (SC) when used as a DC power source. The combination of converter topologies and experimental analysis provides insights into enhancing energy storage systems (ESS) while maintaining high efficiency.

Recommendations:

1. Provide a more comprehensive introduction to establish the context of EDLCs, SCs, and the existing issues with voltage decay during discharge.
2. Discuss the importance of the chemistry, the double layer capacitance, the selection of the electrode materials. Use as a reference the following papers. Ni0.6-xMo0.4-xIrx-oxide as an electrode material for supercapacitors: investigation of the influence of iridium content on the charge storage/delivery. A Gomez Vidales, J Kim, S Omanovic and Nickel oxide on directly grown carbon nanofibers for energy storage applications. A Gomez Vidales, D Sridhar, JL Meunier, S Omanovic
3. Detail the significance and role of the mobile charging station and its relationship to supercapacitor usage in energy storage applications.
4. Provide a thorough explanation of the LCC resonance converter's working principles and advantages in relation to energy storage systems.
5. Include quantitative analysis and comparison of the efficiency improvements achieved using the proposed LCC resonance converter approach compared to traditional methods.
6. Offer insights into the construction and arrangement of the 64.8-V 400-F EDLC bank, highlighting the rationale behind the specific configuration.
7. Clearly explain how the proposed LCC resonance compensation converter achieves optimization, particularly the derivation of the optimum frequency and its implications.
8. Establish a clear link between the constant voltage power characteristics and the concept of optimal power points to aid reader understanding.
9. Provide examples or scenarios of variable load conditions after the initial constant voltage discharge, elaborating on their impact on system performance.
10. Discuss the potential scalability of the proposed system for larger or different capacity applications, addressing any challenges that may arise.
11. Improve the quality of the figures. Also you include 24 separate figures. It is too much, normal papers have less than 10 figures in total, combine some graphs into a figure.

Minor improvements needed

Author Response

Please see the attachment. Thank you.

Author Response File: Author Response.docx

Reviewer 2 Report

In the peer-reviewed paper, the authors investigate the issues of developing a stabilized DC voltage power supply system in which the energy source is a battery of supercapacitors. Many researchers deal with this problem. The authors propose to apply an isolated boost converter of resonant type.

Many questions arose in reading the article.

1. In my opinion, the authors didn't title their article very well. The more correct title is: DC voltage source based on a battery of supercapacitors with a regulator in the form of an isolated boost LCC resonant converter.

2. There are a lot of unclear phrases and terms in the article. 

In the line 98, "To obtain electrical isolation and high efficiency".

In the line 276 'This charging circuit receives 220 VAC of commercial power supply as an input, decompresses it”.

In the line 281 “The voltage is linearly charged”.

In the lines 285, 371, 372 “… output power voltage…”

In the line 391 “the second full bridge inverter”.

In the line 322 “the existing boost converter can electrically insulate the power and load charged through the transformer”.

 3. What are the parameters of the capacitor Cw in Figure 4?

4. There is no reference to Figure 5 in the text of the paper.

5. How is equation (3) obtained?

6. Figure 20 is not referenced. The title of this figure is not clear.

7. In Figures 21 and 22, the axes are not labelled, and the results are not commented on appropriately.

 

Author Response

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Reviewer 3 Report

The paper employs a boost converter to  regulate the output voltage of a super capacitor bank. An electrical double-layer capacitor of 64.8-V 400-F has been constructed for experimental analysis. A resonance compensation has been designed using a first-order harmonic approximation method.  The design has been verified through experimental set up.

The following notes and comments can be taken into consideration to improve the quality of the paper:

1-    In Figure 1, the graph looks exaggerated. It is better to utilize a real curve or add a real (exact) time scale.

2-    In Figure 13 and 15, the cabling and wiring look unoptimized, which will produce unnecessary stray inductance whose effect increases with the increase of switching frequency. Will it produce EMI that affects the operation of the nearby electronic circuits ?

This point should be addressed and explained if this effect is nil. On the other hand, can the experimental prototype be enhanced to alleviate this stray inductance ?

 3-  The system has been tested with resistive load. It should be tested with another type of loads.

4- A complete model of the overall system (Hardware-based circuit model using PSIM for example or mathematical equation-based model) should be added as a separate section.

5- The derivation of output/input relation (voltage transfer function) of the converter should be inserted in the appendix.

Author Response

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Round 2

Reviewer 1 Report

Still a lot of figures included, combine some...

Author Response

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Reviewer 2 Report

The authors have very carefully considered my comments and made appropriate changes and corrections in the text of the article.

I recommend the article for publication in Energies.

Author Response

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