From Non-Modular to Modular Concept of Bidirectional Buck/Boost Converter for Microgrid Applications
Round 1
Reviewer 1 Report
This paper presents a practical comparison of efficiency and other working parameters of the modular and non-modular converter solutions of the bidirectional DC/DC converters. An interesting work is conducted. The comments on this paper are as follows:
- The references are not correctly cited in the context. Please check it.
- The application of dc microgrids and the motivation of this research can be further discussed. The following references for dc microgrids could be useful: DOI: 10.1109/TSTE.2019.2956054. DOI: 10.1109/TEC.2019.2936120.
- The contribution is not clearly discussed. Please justify the limitations of existing works and the novelties of this paper.
- 1 is not correct. The ac/dc converter connecting dc microgrid and the main grid is drawn inversely. Besides, the control block is rather unclear. Does it refer to primary control or upper-level controller?
- Section II is mainly from existing works. Please give suitable references.
- A guideline for designing the modular converter can be given based on the analysis.
Author Response
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Reviewer 2 Report
English needs significant improvement.
Abstract: "It deals with ..." is difficult to understand ...
Intro: "A microgrid ..." use standard microgrid definition for this sentence and cite the reference.
many reference brackets have no reference numbers. this needs to be corrected.
equation numbering must be sequential - it is presently not so.
Page 2, line 53. the sentence makes no sense to this editor.
Page 3, line 76. the sentence makes no sense to this editor.
Page 3: Figure 2 is given with no reference and as if it is self evident. This is not acceptable.
Page 3: Figure 3; the topology has a non-standard diode that needs to be explained.
Page 4, Line 87 - 90. This sentence/paragraph should be done with figure 8 moved up to this point in the paper so the reader knows what is going on.
Page 4: Lifetime of caps is largely irrelevant. Selection is key.
Page 4: ESR >> standard ripple voltage levels.
Page 4: equations are given with no reference or derivation. This needs to be corrected.
Page 5 Figure 4 needs reference citing.
Table 3 needs to be justified.
Page 6 - 7: equation references and sequential numbering needed (or a derivation of).
Appendix A: currents vs. time are given with no detailed justification and references an incorrect figure.
Table A1 is given without enough information as to enable a reader to derive results. this needs to be corrected.
Table 2 in appendix 1 should be labeled as 'Table A2'
Comments regarding appendix 1 are likewise appropriate for appendix 2
Author Response
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Reviewer 3 Report
The topic under consideration of this article is an notable trend of the microgrid power systems. However, this article is poorly presented with too many flaws. Here are some examples:
- The equations (1)-(3) are very confusing in terms of variable names. The authors must connect the names with the variables, and explain where do these equations come from.
- The format of some variables must be consistent. For example, is "L.f_sw" in eq. (2) and (3) the same as "Lf_sw" in eq. (4)?
- What does the "*" mean in eq. (1) on Page 6?
- Equation numbers (1) (2) (3) are repeating.
- I assume the symbol "[X]" on Line 47, Page 2 was supposed to be a reference? There are so many "[X]" through out this paper.
Author Response
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Round 2
Reviewer 1 Report
Sufficient improvement has been conducted by the authors.
Author Response
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Reviewer 2 Report
Version 2 is much improved over Version 1.
The flow, explanations, and attention to logical details has been significantly improved.
However ...
In version 1, one of the points that needed addressing was the diode D1 shown in the circuits of Figure 3. This diode is not typical and I requested an explanation. Furthermore, diode D1 appears in the circuit illustrated in Figure 14 of version 1. In version 2, diode D1 has been removed from the circuits illustrated in Figure 3 but still remains in the circuit illustrated in Figure 14. An explanation is needed as to what diode D1 is doing. Simply deleting it from Figure 3 of version 2 is not acceptable.
When this diode question is addressed to this editors satisfaction, then I will approve the draft for publication.
Finally, as a matter of the English language semantics, the phrase "cons and pros" is typically rendered as "pros and cons".
Author Response
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Reviewer 3 Report
The revised version is significantly improved from the first time. However, the reviewer still has concerns on the novelty of this paper. It looks like all the equations were cited from others' works. The authors first shall explain the original contribution of this paper. It is not very persuasive at this moment.
There are some new findings in the literature about this topic. It would be better if the authors compare their method with the ones in these papers:
- Monadi, Mehdi, et al. "Centralized protection strategy for medium voltage DC microgrids." IEEE Transactions on Power Delivery 32.1 (2016): 430-440.
- Zhang, Yucheng, et al. "Energy and fuel utilization of SiC-based 400V DC distribution network and 208V AC distribution network with distributed resources installation." 2017 IEEE 12th International Conference on Power Electronics and Drive Systems (PEDS). IEEE, 2017.
- Su, Mei, et al. "Stability analysis and stabilization methods of DC microgrid with multiple parallel-connected DC–DC converters loaded by CPLs." IEEE Transactions on Smart Grid 9.1 (2016): 132-142.
- Chang, Chien-Hsuan, et al. "Design and implementation of a two-switch buck-boost typed inverter with universal and high-efficiency features." 2015 9th International Conference on Power Electronics and ECCE Asia (ICPE-ECCE Asia). IEEE, 2015.
- Zhang, Yucheng, et al. "Study of a 3kW high-efficient wide-bandgap DC-DC power converter for solar power integration in 400V DC distribution networks." 2017 IEEE 12th International Conference on Power Electronics and Drive Systems (PEDS). IEEE, 2017.
In addition, some minor changes shall be addressed:
- In Figure 2, which one is "up" and which is "bottom"?
- Some format/language errors need to be thoroughly checked. For instance, the authors citing "fig. X" in this paper, however, all the plots are captioned as "Figure X".
- The format of the references are not consistant. Some are Last_Name, F. Some are F. Last_Name
Author Response
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Round 3
Reviewer 2 Report
acceptable to this reviewer
Author Response
Hereby we would like to thank to the reviewer for his satisfactory evaluation of the revisions.
Reviewer 3 Report
This present version is overall acceptable. The authors should go through this paper again very carefully because still errors and typos are there in this version.
For example, Page 1 Line 35 ".."; Page 3 line 84 "[-24]"?
Author Response
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