A Bidirectional Resonant Converter Based on Partial Power Processing
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper presents a bidirectional resonant converter based on partial power processin that integrates an LLC-DCX converter with a bidirectional synchronous Buck/Boost circuit to achieve soft switching, wider voltage gain range and high efficiency.
The topic of the paper is timely and its overall structure is well-organized. The paper is technically sound, however there are significant concerns that need to be properly addressed.All the following concerns should be adequately addressed in the revision:
1. The section discussing the contribution of the work in introduction is quite limited. The main novelty of the proposed topology and rationale behind its design should be explained more convincingly with more clear justifications and better clarification.
2. Regarding dynamic power distribution(Fig. 14 and 16), can you explain better how does power distribution between the main and partial power circuits change during transients? Have you measured efficiency degradation under dynamic load changes?
3.The converter achieves peak efficiencies of 97.74%(forward) and 96.9% (reverse) but adding a discussion on efficiency at light loads or high duty cycles (for example d>0.75 or d<0.3, etc.) seems necessary (since also real-world implementations often suffer from partial hard switching at light loads and maybe switching to CCM at lower loads can reduce conduction losses).
4. Several studies have explored the use of alternative bidirectional topologies and power regulation methods, such as flyback or isolated buck-boost converters, which offer notable advantages in terms of voltage gain flexibility and dynamic performance. For instance, the works in (the refences that can be cited and discussed in the revised version) https://doi.org/10.3906/elk-1502-213 and https://doi.org/10.1109/TPEL.2018.2794332 investigate how these isolated configurations address key challenges including stability, robustness,and harmonic rejection in energy conversion. Consideiring the focus of this paper on partial power processing for bidirectional converters, it would be valuable to discuss how the proposed approach compares to such existing topologies in terms of control complexity, component stress, and real-world implementation feasibility. Or maybe clarifying if the proposed strategy offer any significant advantages over these referenced designs in terms of efficiency trade-offs, ZVS reliability,EMI reduction, etc. The manuscript should at least include a discussion of these works and highlight the benefits of proposed strategy compared to them.
5. the Buck/Boost stage operates in FCCM mode. Adding a comparison between its efficiency with standard CCM mode can be valuable to check whether FCCM introduces additional conduction losses or not (FCCM may lead to higher circulating currents, etc.). In fact, the authors should highlight how the experimental efficiency compare with recent bidirectional LLC resonant converters in the literature and conventional dual-active bridge (DAB) designs, etc.
6. In general, while the paper claims the proposed design improves efficiency over traditional LLC or bidirectional DAB converters, but where is the direct experimental comparison?
Author Response
We would like to thank you for your valuable comments and helpful suggestions concerning our manuscript. We have carefully revised the manuscript to improve its quality. We hope the revised paper is satisfactory.
Comments 1: The section discussing the contribution of the work in introduction is quite limited. The main novelty of the proposed topology and rationale behind its design should be explained more convincingly with more clear justifications and better clarification.
Response 1: Thanks for your suggestion and we agree with this comment. We have revised the contribution to this work in the introduction as follows“ This paper presents a new design for a bidirectional resonant converter that is based on the principle of partial power processing. It aims to expand the voltage gain range of the LLC converter. This design is capable of meeting the charging and discharging requirements between energy storage batteries and DC voltage bus, offering substantial benefits such as increased efficiency and a wide gain range. Within this framework, the main power pathway incorporates an LLC converter operating at its resonant frequency to optimize the performance of the bidirectional converter. At the same time, the bidirectional synchronous buck/boost converter is used to process partial power to control the output voltage.”
Comments 2: Regarding dynamic power distribution(Fig. 14 and 16), can you explain better how does power distribution between the main and partial power circuits change during transients? Have you measured efficiency degradation under dynamic load changes?
Response 2: Thank you for your questions. This paper studies a new type of bidirectional power resonant converter based on the processing principle, mainly used in energy storage with the charge and discharge between the DC busbar. Figure 14 and Figure 16 show the voltage and power distribution of the main power circuit and partial power circuit at different operating times. In the forward working mode, the system adopts the two-stage charging strategy of constant current (CC) and constant voltage (CV). Due to the characteristics of storage battery, the load power shows a slow change trend and will not mutate. In the CC charging stage, the load power increases gradually with the gradual increase of the battery voltage. In this process, because the load power changes gently, the output of the main power circuit remains stable, while the output of some power circuits increases accordingly to meet the demand of the load power. In the CV charging stage, the load power also does not change dramatically. As the charging current decreases, the output of the main power circuit and part of the power circuit simultaneously decreases, but the power distribution ratio of the two remains unchanged. Figure 15 in the original article shows the efficiency curve for both CC and CV charging modes. Since the load power changes dynamically in this process, the efficiency curve can effectively reflect the efficiency characteristics of the system under different load power conditions. In the backward working mode, the efficiency is measured for the maximum output power under different battery voltages. However, the efficiency characteristics of different load conditions at the same battery voltage have not been tested in detail, which will be one of the focuses of future research efforts. We plan to conduct further in-depth studies on the impact of load changes on efficiency in the follow-up work to fully evaluate the performance of the system.
Comments 3: The converter achieves peak efficiencies of 97.74%(forward) and 96.9% (reverse) but adding a discussion on efficiency at light loads or high duty cycles (for example d>0.75 or d<0.3, etc.) seems necessary (since also real-world implementations often suffer from partial hard switching at light loads and maybe switching to CCM at lower loads can reduce conduction losses).
Response 3: The converter operates at a fixed frequency at the resonant frequency point, and its two output voltages remain essentially constant. During the constant current (CC) charging process, as the battery voltage increases from 350V to 450V, the output voltage of the partial power circuit correspondingly changes from 54V to 154V, with the duty cycle adjusting from 0.283 to 0.806, covering a wide range from low to high duty cycles. Since the partial power circuit adopts a synchronous Buck/Boost topology, the inductor current always operates in continuous conduction mode (CCM). To ensure zero-voltage switching (ZVS) across the full load range, the inductor parameters are designed based on critical conditions, ensuring that the inductor current exhibits reverse polarity within one switching cycle at maximum output current. As shown in Fig. R1, even under no-load conditions, the average inductor current is close to zero, but its instantaneous value fluctuates between positive and negative, enabling ZVS. Therefore, the converter can achieve ZVS across the entire load range. However, under light-load conditions, the reactive circulating current in the partial power circuit increases significantly, leading to higher conduction losses and reduced system efficiency. This issue will be further optimized in future research to improve performance under light-load conditions.
Fig. R1
Comments 4: Several studies have explored the use of alternative bidirectional topologies and power regulation methods, such as flyback or isolated buck-boost converters, which offer notable advantages in terms of voltage gain flexibility and dynamic performance. For instance, the works in (the refences that can be cited and discussed in the revised version) https://doi.org/10.3906/elk-1502-213 and https://doi.org/10.1109/TPEL.2018.2794332 investigate how these isolated configurations address key challenges including stability, robustness, and harmonic rejection in energy conversion. Considering the focus of this paper on partial power processing for bidirectional converters, it would be valuable to discuss how the proposed approach compares to such existing topologies in terms of control complexity, component stress, and real-world implementation feasibility. Or maybe clarifying if the proposed strategy offer any significant advantages over these referenced designs in terms of efficiency trade-offs, ZVS reliability, EMI reduction, etc. The manuscript should at least include a discussion of these works and highlight the benefits of proposed strategy compared to them.
Response 4: This article adds a comparison with other converters in the table below.
Table R1
Comments 5: the Buck/Boost stage operates in FCCM mode. Adding a comparison between its efficiency with standard CCM mode can be valuable to check whether FCCM introduces additional conduction losses or not (FCCM may lead to higher circulating currents, etc.). In fact, the authors should highlight how the experimental efficiency compare with recent bidirectional LLC resonant converters in the literature and conventional dual-active bridge (DAB) designs, etc.
Response 5: Compared to CCM, the FCCM introduces increased reactive circulating currents, leading to higher conduction losses. However, FCCM significantly reduces switching losses. Additionally, the selected switching, IPW60R105CFD7, is a Si MOSFET. If CCM mode were adopted, the energy of reverse recovery would be converted into heat, degrading efficiency. The high-frequency oscillations during switching transients would exacerbate electromagnetic interference (EMI), compromising system stability, and induce voltage stress (e.g., Vds spikes) on the switching device, potentially damaging it. Therefore, after comprehensive consideration, the FCCM mode is chosen.
Comments 6: In general, while the paper claims the proposed design improves efficiency over traditional LLC or bidirectional DAB converters, but where is the direct experimental comparison?
Response 6: In the Table R1, the performance and efficiency of the proposed converter are compared with hybrid converter, LLC converter, CLLC converter and DAB converter respectively, and the performance advantages of the converter are intuitively shown.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe proposed bidirectional resonant converter that integrates partial power processing is an innovative approach in improving the efficiency and flexibility of LLC resonant converters.
Here are my comments.
1. Including a benchmark comparison with conventional designs might highlight the advantages of the proposed topology more effectively.
2. The paper could benefit from discussing how the design can be scaled for different power ratings, especially in large energy storage systems or electric vehicles.
3. There is little discussion on the sensitivity of the converter's performance to variations in key parameters such as temperature, component tolerances, or aging.
4. Addressing how the design minimizes EMI or incorporating a discussion of EMI mitigation techniques would be beneficial.
5. The authors may add in the introduction the potential and prospects of the LLC resonant converter proposed in this paper for application in electrical vehicles. Some references are recommended as follows.
[R] Wei, X.; Shi, Y.; Li, G.; Zhang, Z.; Chang, S. Wide-Load-Range Double-T Resonant Converter for CC/CV Battery Charging. Electronics 2024, 13, 533. https://doi.org/10.3390/electronics13030533.
[R] X. Meng, Q. Zhang, Z. Liu, G. Hu, F. Liu and G. Zhang, "Multiple Vehicles and Traction Network Interaction System Stability Analysis and Oscillation Responsibility Identification," in IEEE Transactions on Power Electronics, vol. 39, no. 5, pp. 6148-6162, May 2024, doi: 10.1109/TPEL.2023.3347472.
Author Response
Thank you for your recognition of our work and we sincerely appreciate your suggestions. Your comments are extremely valuable for improving the quality of our manuscript. We are grateful for this opportunity and have made our best effort to revise the manuscript based on your feedback.
Comments 1: Including a benchmark comparison with conventional designs might highlight the advantages of the proposed topology more effectively.
Response 1: The performance and efficiency of the proposed converter are compared with hybrid converter, LLC converter, CLLC converter and DAB converter respectively, and the performance advantages of the converter are intuitively shown.
Table R1
Comments 2: The paper could benefit from discussing how the design can be scaled for different power ratings, especially in large energy storage systems or electric vehicles.
Response 2: Thanks for your suggestion and we agree with this comment. We have revised the contribution to this work in the introduction as follows “This paper presents a new design for a bidirectional resonant converter that is based on the principle of partial power processing. It aims to expand the voltage gain range of the LLC converter. This design is capable of meeting the charging and discharging requirements between energy storage batteries and DC voltage bus, offering substantial benefits such as increased efficiency and a wide gain range. Within this framework, the main power pathway incorporates an LLC converter operating at its resonant frequency to optimize the performance of the bidirectional converter. At the same time, the bidirectional synchronous buck/boost converter is used to process partial power to control the output voltage.”
Comments 3: There is little discussion on the sensitivity of the converter's performance to variations in key parameters such as temperature, component tolerances, or aging.
Response 3: This paper primarily investigates a bidirectional half-bridge resonant converter with partial power regulation, which combines the advantages of resonant converters and PWM converters. However, the sensitivity of the converter to variations in key parameters, such as temperature, component tolerances, or aging, has not been studied. These aspects will be further investigated and discussed in future work.
Comments 4: Addressing how the design minimizes EMI or incorporating a discussion of EMI mitigation techniques would be beneficial.
Response 4: It is agreed that the soft switching circuit has a small EMI problem, and this circuit can achieve ZVS of all switches, so the EMI problem will not be serious, but we do not have EMI testing equipment and do not carry out research work in this area.
Comments 5: The authors may add in the introduction the potential and prospects of the LLC resonant converter proposed in this paper for application in electrical vehicles. Some references are recommended as follows.
[R] Wei, X.; Shi, Y.; Li, G.; Zhang, Z.; Chang, S. Wide-Load-Range Double-T Resonant Converter for CC/CV Battery Charging. Electronics 2024, 13, 533. https://doi.org/10.3390/electronics13030533.
[R] X. Meng, Q. Zhang, Z. Liu, G. Hu, F. Liu and G. Zhang, "Multiple Vehicles and Traction Network Interaction System Stability Analysis and Oscillation Responsibility Identification," in IEEE Transactions on Power Electronics, vol. 39, no. 5, pp. 6148-6162, May 2024, doi: 10.1109/TPEL.2023.3347472.
Response 5: We have revised the introduction in response to the comments.
Reviewer 3 Report
Comments and Suggestions for AuthorsRemarks:
1. The labels of the timing diagrams in Figure 4 are too small and unreadable without magnification. It would be good to enlarge them.
2. It would be good to cite the source from which expression (3) is taken, as it has not been derived beforehand, nor have theoretical considerations been made to derive it.
3. The diagrams presented in Figure 7 are too small and not legible when printed. It would be better to present 2 per line and enlarge them.
4. The oscillograms presented in Figures 10, 11, 12 and 13 are too small and illegible when printed. It would be better to enlarge them or present the ZVS area of each of them separately.
Specific comments:
1. There are some spelling and technical errors in the text ( lines 268, 274, etc.).
2. For easier identification of the individual quantities on the oscillograms, it would be better to give the colour of the individual curves and their corresponding voltages and currents in the subfigure captions or text.
Conclusion:
The manuscript is suitable for the field of Electronics journal, presented in a well-structured manner with clear scientific language and appropriate mathematical apparatus. The references cited are relevant, including 24 of the 31 cited in the paper from the last 5 years. There is only one self-citation that is adequate and directly related to the purpose of the study. The paper is scientifically based, with theoretical generalizations actually confirmed by experiment. The figures, tables and diagrams presented are clear and appropriate to properly present the results obtained. They are easy to calculate and understand by any power electronics specialist. The conclusions drawn are consistent with the evidence and arguments presented.
Author Response
We are grateful to editors and all the reviewers for their constructive comments and suggestions on the revision of our manuscript. All the comments are valuable and helpful for revising and improving our paper.
Comments 1: The labels of the timing diagrams in Figure 4 are too small and unreadable without magnification. It would be good to enlarge them.
Response 1: We have made changes to Figure 4, and its labels are clear.
Comments 2: It would be good to cite the source from which expression (3) is taken, as it has not been derived beforehand, nor have theoretical considerations been made to derive it.
Response 2: We have cited Formula (3) from the literature and indicated its source.
Comments 3: The diagrams presented in Figure 7 are too small and not legible when printed. It would be better to present 2 per line and enlarge them.
Response 3: We have reformatted the image in Figure 7.
Comments 4: The oscillograms presented in Figures 10, 11, 12 and 13 are too small and illegible when printed. It would be better to enlarge them or present the ZVS area of each of them separately.
Response 4: We have enlarged figures 10,11,12, and 13.
Specific comments:
1: There are some spelling and technical errors in the text ( lines 268, 274, etc.).
2: For easier identification of the individual quantities on the oscillograms, it would be better to give the color of the individual curves and their corresponding voltages and currents in the subfigure captions or text.
Response : We appreciate your specific comments and we have checked and revised the original text.
Reviewer 4 Report
Comments and Suggestions for AuthorsThe article presents a bidirectional converter using LLC and a synchronous buck converter. The main novelty should be the topology according to the authors, but actually it has already been presented in previous works. The real novelty could be the partial power processing, that seems to provide good results in terms of efficiency in different conditions.
The introduction is quite extensive, even if some significant works should also be cited, in particular referring to the control strategies of LLC converters (e.g. 10.1109/ECCE50734.2022.9947909).
One major comment is that you identify the dc/dc converter as a buck/boost, but actually it is a synchronous buck converter, as also confirmed by the voltage gain in eq. (10). This must be revised throughout all the paper. It is a major methodological error.
In Fig.2: If Va is kept constant, also Pa is expected to be constant, right? But it reduces between t1 and t2.
Pag.4, line 151: this statement should be accompanied by a proper citation.
Pag.5, line 162: same issue. Cite e.g. 10.1109/SPEEDAM.2006.1649771
What are the "leakage source voltage" and "grid-source voltage" at pag.7 line 205 and pag.12 line 350, respectively?
Section 1 of paragraph 4.2 is a repetition of what is written at the end of section 3. One of the two must be eliminated.
The experimental results are well presented and highlight a very good design of the power converter.
There are many typos and English language errors that must be corrected.
Comments on the Quality of English LanguageEnglish language can be improved by far. There are also many typos and lexicon errors throughout all the article. Please revise carefully the paper.
Author Response
Thank you for your recognition of our work and we sincerely appreciate your suggestions. Your comments are extremely valuable for improving the quality of our manuscript. We are grateful for this opportunity and have made our best effort to revise the manuscript based on your feedback.
Comments 1: One major comment is that you identify the dc/dc converter as a buck/boost, but actually it is a synchronous buck converter, as also confirmed by the voltage gain in eq. (10). This must be revised throughout all the paper. It is a major methodological error.
Response 1: The topology studied in this paper is the partial power bidirectional resonant converter topology, because it is a bidirectional conversion, in the forward mode, the partial power converter is a synchronous Buck converter, in the backward mode, it is a synchronous Boost converter, so it is called Buck/Boost converter.
Comments 2: In Fig.2: If Va is kept constant, also Pa is expected to be constant, right? But it reduces between t1 and t2.
Response 2: Fig.2 has been modified according to the constant - current output condition. In fact, Fig.2 in the original text represents the relationship under the condition of constant - power load.
Comments 3: Pag.4, line 151: this statement should be accompanied by a proper citation. Pag.5, line 162: same issue. Cite e.g. 10.1109/SPEEDAM.2006.1649771
Response 3: Thank you for your efforts. We have cited the relevant literature.
Comments 4: What are the "leakage source voltage" and "grid-source voltage" at pag.7 line 205 and pag.12 line 350, respectively?
Response 4: We are very sorry for our negligence in replacing "drain source voltage" and "gate source voltage" with "leakage source voltage" and "grid source voltage". We sincerely apologize for this mistake.
Comments 5: Section 1 of paragraph 4.2 is a repetition of what is written at the end of section 3. One of the two must be eliminated.
Response 5: Thank you for your advice. We have made changes to it.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have addressed some of my concerns sufficiently, but the revisions are insufficient in some aspects. My concerns related to the depth of explanation, the comparisons, and the clarity of the manuscript should be properly addressed. Below, I provide more details:
Regarding comment 1, the revision still does not have a strong justification for the design choices. While the new paragraph expands on the contribution, it needs to be more analytical rather than descriptive. The authors should explicitly highlight how their approach is different from existing solutions (at least most related concerns) and why this specific topology was chosen.
Regarding comment 2, the authors claim that ZVS is achieved across all load conditions, but this lacks proper validation. The response also does not address how efficiency compares to other bidirectional LLC converters under similar conditions.
Regarding comment 4, although a comparison table has been added, it does not include the suggested papers in my first review to analyze the contribution of this work over the existing related references.
Regarding comment 5, while the choice of FCCM over CCM is justified in terms of reducing switching losses and mitigating reverse recovery issues in Si MOSFETs, the response seems to oversimplify the trade-offs. FCCM inherently introduces increased reactive circulating currents, which can lead to higher conduction losses specially at light loads. While reverse recovery losses in CCM can degrade efficiency, this is highly dependent on the device type, for instance SiC or GaN MOSFETs could significntly mitigate this issue. Also, the claim that FCCM minimizes EMI and voltage stress overlooks the fact that proper gate drive design and snubber circuits can effectively address these concerns in CCM. Therefore, I believe while FCCM may offer advantages, its superiority is not absolute and I guess a more balanced discussion of its trade-offs is necessary to be added to the paper.
Author Response
Comments 1: Regarding comment 1, the revision still does not have a strong justification for the design choices. While the new paragraph expands on the contribution, it needs to be more analytical rather than descriptive. The authors should explicitly highlight how their approach is different from existing solutions (at least most related concerns) and why this specific topology was chosen.
Response 1: Thank you very much for your comments. You pointed out that although the revised paragraph expanded on the description of the contributions, it still lacked sufficient analytical content and failed to clearly distinguish our method from existing solutions. We are very grateful for this feedback and have further revised and supplemented the relevant sections. We add this on page 2 of the article.
Comments 2: Regarding comment 2, the authors claim that ZVS is achieved across all load conditions, but this lacks proper validation. The response also does not address how efficiency compares to other bidirectional LLC converters under similar conditions.
Response 2: Thank you very much for your comments. In Section 4 of the paper, the parameter design of the circuit is discussed in detail, including the parameter conditions for achieving soft switching in both the LLC resonant converter and the synchronous Buck converter. The synchronous Buck converter operates in the FCCM, which forces the inductor current into continuous conduction to avoid discontinuities. Moreover, by introducing auxiliary resonant components and optimizing the dead time, the input impedance can exhibit inductive characteristics, providing conditions for ZVS of the switches S7 and S8. The parameters ultimately chosen meet the conditions for soft switching even under the most stringent operating conditions, as analyzed theoretically, thereby ensuring ZVS across all load conditions.
Comments 3: Regarding comment 4, although a comparison table has been added, it does not include the suggested papers in my first review to analyze the contribution of this work over the existing related references.
Response 3: Thank you very much for your valuable comments. In your first review, you recommended two references: https://doi.org/10.3906/elk-1502-213 ("A new method for active power factor correction using a dual-purpose inverter in a flyback converter") and https://doi.org/10.1109/TPEL.2018.2794332 ("Partially Isolated Single-Magnetic Multiport Converter Based on Integration of Series-Resonant Converter and Bidirectional PWM Converter"). We have incorporated the second reference into our paper (listed as Ref. [31]). However, after careful consideration, we concluded that the first reference is not well-aligned with the theme of our paper.
Our paper primarily focuses on the design of a partially regulated bidirectional resonant converter. In contrast, the reference you suggested is centered on a novel active power factor correction (PFC) method. Specifically, it introduces a dual-purpose inverter in a flyback converter to eliminate input current harmonics and improve the power factor, as shown in Fig. R1. Although both papers deal with the design of power electronic converters, the research objectives and application scenarios are significantly different. The dual-purpose inverter technique proposed in that reference is mainly aimed at solving the PFC problem in single-phase AC/DC flyback converters and involves a backup power supply and SPWM control methods. These technical details are not directly related to the content of our study, and including this reference might blur the focus of our research.
Fig. R1
Comments 4: Regarding comment 5, while the choice of FCCM over CCM is justified in terms of reducing switching losses and mitigating reverse recovery issues in Si MOSFETs, the response seems to oversimplify the trade-offs. FCCM inherently introduces increased reactive circulating currents, which can lead to higher conduction losses specially at light loads. While reverse recovery losses in CCM can degrade efficiency, this is highly dependent on the device type, for instance SiC or GaN MOSFETs could significntly mitigate this issue. Also, the claim that FCCM minimizes EMI and voltage stress overlooks the fact that proper gate drive design and snubber circuits can effectively address these concerns in CCM. Therefore, I believe while FCCM may offer advantages, its superiority is not absolute and I guess a more balanced discussion of its trade-offs is necessary to be added to the paper.
Response 4: Thank you very much for your in-depth analysis and valuable comments on this paper. The trade-offs between FCCM and CCM that you mentioned in your comments are indeed very important. Using SiC or GaN MOSFETs can significantly mitigate reverse recovery losses. However, in this paper, we mainly focus on designing with Si MOSFETs, and the cost would also increase if we use new devices.
You pointed out that gate drive design and snubber circuits can effectively address the EMI and voltage stress issues in CCM. While these designs can improve performance, they also introduce additional losses. For example, the gate drive circuit itself consumes a certain amount of power, especially under high-frequency switching conditions. Moreover, snubber circuits (such as RC snubber circuits) can reduce voltage overshoot and EMI, but they also increase conduction losses.
Using CCM, the energy from reverse recovery is converted into heat, reducing efficiency. High-frequency oscillations during switching transients can exacerbate EMI, affect system stability, and induce voltage stress on the switching devices, which may damage them.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have made efforts to improve the efficiency and voltage gain regulation of bidirectional resonant converters. However, there are still areas that need to optimize.
1. Could the authors clarify the limitations of the existing solutions more explicitly before introducing their proposed approach?
2. On Page 6, Eq. (3), the derivation of the normalized gain formula should be better explained for clarity. Could you provide a brief step-by-step derivation or cite a reference where this is explained in more detail?
3. Figure 6 (Key waveform of Buck/Boost converter in FCCM mode) lacks clear axis labels for time and voltage/current.
4. Some sentences are quite long, making them difficult to read.
Author Response
Comments 1: Could the authors clarify the limitations of the existing solutions more explicitly before introducing their proposed approach?
Response 1: Thank you very much for your valuable comment that we need to be more explicit about the limitations of existing solutions before introducing new approaches. We fully agree with this and have revised and supplemented the relevant sections to show more clearly the inadequacies of the existing approach. We add this on page 2 of the article.
Comments 2: On Page 6, Eq. (3), the derivation of the normalized gain formula should be better explained for clarity. Could you provide a brief step-by-step derivation or cite a reference where this is explained in more detail?
Response 2: Thank you very much for your expenditure, which we have already made up on page 5.
Comments 3: Figure 6 (Key waveform of Buck/Boost converter in FCCM mode) lacks clear axis labels for time and voltage/current.
Response 3: We have made changes to Figure 6.
Comments 4: Some sentences are quite long, making them difficult to read.
Response 4：Thank you for your suggestion. We have proofread and revised the article.
Reviewer 4 Report
Comments and Suggestions for AuthorsThe main concerns have been solved according to most of my comments.
Please correct in Fig.5: synchronous instead of synchronization.
I still have one methodological concern:
Although the topology presented is bidirectional and, depending on the power flow, the non-isolated converter can work either in buck or in boost mode, the synchronous buck/boost converter is a different concept of power converter. You should not confuse the modes of operation with the topology. This ambiguity must be well clarified in the article, referring to the different modes of operation and not to a buck/boost converter throughout the text.
Author Response
Comments 1: Please correct in Fig.5: synchronous instead of synchronization.
Response 1: Thank you very much for your expenditure, which we have already made up in Fig.5.
Comments 2: I still have one methodological concern:
Although the topology presented is bidirectional and, depending on the power flow, the non-isolated converter can work either in buck or in boost mode, the synchronous buck/boost converter is a different concept of power converter. You should not confuse the modes of operation with the topology. This ambiguity must be well clarified in the article, referring to the different modes of operation and not to a buck/boost converter throughout the text.
Response 2: Thank you very much for your detailed review and valuable comments on this paper. The distinction between the topology and the mode of operation that you pointed out is indeed very important. We understand the confusion you highlighted and have revised the relevant sections to more clearly clarify the different modes of operation. We have changed the term “bidirectional synchronous Buck/Boost converter” in the text to “synchronous Buck converter” or “synchronous Boost converter” depending on the specific mode.
Round 3
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript has improved compared to the initial version.
Reviewer 4 Report
Comments and Suggestions for AuthorsThank you for addressing the comments. I am satisfied with the latest version of your article.
