Cascaded AC-DC Power Conversion Interface for Charging Battery

Round 1

Reviewer 1 Report

In this manuscript, the authors design and demonstrate a cascaded AC-DC power conversion interface, abbreviated as CADPCI, with improved performance. In particular, CADPCI is able to output stable DC voltage and current, with unity power correction. The authors also compare its performance with existing AC-DC conversion technologies and highlight the unique advantages of CADPCI, such as preventing the drawbacks of the step-down ratio in a PFC circuit. The ideas and experiments are discussed well with details and clarity. Given the rapid development of electric vehicle, I think the technology introduced in this work will be interesting and valuable to broad community. Therefore, I’d like to see its publication in Electronics. However, should the authors have a chance, it would be best if they can address the following questions.

 

1.     The authors show an 800W prototype and its experimental results in Section 8. I wonder what the maximum power is CADPCI can operate? And what is it limited by?

 

2.     It would be great if the authors can discuss with details about some real-world application examples of CADPCI (such as electric vehicle), in which it can significantly outperform other technologies. The authors should also discuss the feasibility of mass production and potential challenges. 

 

3.     Typos should be removed. For example, in line 83, “An independence DC source is necessary for each FBC, … ” should be “An independent DC source is necessary for each FBC, … ” The authors should check through the manuscript to get rid of all errors.

Author Response

Reviewer 1

Point 1:

In this manuscript, the authors design and demonstrate a cascaded AC-DC power conversion interface, abbreviated as CADPCI, with improved performance. In particular, CADPCI is able to output stable DC voltage and current, with unity power correction. The authors also compare its performance with existing AC-DC conversion technologies and highlight the unique advantages of CADPCI, such as preventing the drawbacks of the step-down ratio in a PFC circuit. The ideas and experiments are discussed well with details and clarity. Given the rapid development of electric vehicle, I think the technology introduced in this work will be interesting and valuable to broad community. Therefore, I’d like to see its publication in Electronics. However, should the authors have a chance, it would be best if they can address the following questions.

Response 1:

The authors would like to express our gratitude to the reviewer for taking the valuable time to review this paper.

Point 2:

The authors show an 800W prototype and its experimental results in Section 8. I wonder what the maximum power is CADPCI can operate? And what is it limited by?

Response 2:

Thank you for the valuable comment.

The maximum power of CADPCI depends on the power rating of used power devices, including power MOSFETs, diodes, inductors, capacitors, and PCB. Due to limited laboratory resources, the prototype only operates under 800W. In general, the rated power of single-phase chargers ranges from several watts to several thousand watts. If the rated power of the power device increases expanded, the rated power of the proposed CADPCI could reach several kilowatts.

Point 3:

It would be great if the authors can discuss with details about some real-world application examples of CADPCI (such as electric vehicle), in which it can significantly outperform other technologies. The authors should also discuss the feasibility of mass production and potential challenges.

Response 3:

Thank you for the valuable comment.

The proposed CADPCI has the advantages of higher power efficiency, the lower capacity of the passive filter, and the EMI. Hence, the proposed CADPCI is suitable for charging the battery of electric vehicles, robots, home-based battery energy storage systems, etc.

Point 4:

Typos should be removed. For example, in line 83, “An independence DC source is necessary for each FBC, … ” should be “An independent DC source is necessary for each FBC, … ” The authors should check through the manuscript to get rid of all errors.

Response 4:

Thank you for the valuable comment.

It has been corrected in the revised version. In the revised paper, the authors did try the best to correct the errors from the previous edition.

Author Response File: Author Response.pdf

Reviewer 2 Report

One of the main disadvantages of the proposed topology is using a high number of devices which would decrease the efficiency. You need to give a comprehensive efficiency analysis and comparison.

You need to derive PF and THD at the grid side for different power levels.

 

Author Response

Reviewer 2

Point 5:

One of the main disadvantages of the proposed topology is using a high number of devices which would decrease the efficiency. You need to give a comprehensive efficiency analysis and comparison.

Response 5:

Thank you for the valuable comment.

Based on this comment, the authors modified part of section 4 for the efficiency analysis and comparison between the proposed approach and the other competitors. The efficiency of the experimental results is provided in section 7.

Point 6:

You need to derive PF and THD at the grid side for different power levels.

Response 6:

Thank you for the valuable comment.

To respond to this constructive suggestion, the authors modified section 7 to provide PF and THD information of the proposed approach.  

(Detail responses are shown in the pdf file.)

 

Author Response File: Author Response.pdf

Reviewer 3 Report

In order to keep the advantage on the continuous input current of the boost type PFC circuits, but eliminate the drawback on the high step-down ratio of the second stage and high transition voltage level, this paper proposes a cascaded AC-DC power conversion interface  to convert AC power from the utility into stable DC power to charge the battery set. The proposed CADPCI is composed of a cascaded converter and a dual-input buck converter.

To improve the paper, the following specify comments are recommended to be considered (more details can be found in the attachment):

1. For battery charge and discharge control should be added.

2. How to select the control parameters? More details should be provided regarding this issue.

3. Pictures of the experimental platform should be provided.

4. It is recommended that the results of the experiment be collated into a table to highlight the advantages.

Author Response

Reviewer 3

Point 7:

In order to keep the advantage on the continuous input current of the boost type PFC circuits, but eliminate the drawback on the high step-down ratio of the second stage and high transition voltage level, this paper proposes a cascaded AC-DC power conversion interface  to convert AC power from the utility into stable DC power to charge the battery set. The proposed CADPCI is composed of a cascaded converter and a dual-input buck converter.

To improve the paper, the following specify comments are recommended to be considered (more details can be found in the attachment):

Response 7:

The authors would like to express our gratitude to the reviewer for taking the valuable time to review this paper.

Point 8:

For battery charge and discharge control should be added.

Response 8:

Thank you for the valuable comment.  

In the control block of the CC shown in Figure 9, the amplitude signal is controlled by constant current/constant voltage (CC/CV) charging strategy for the battery set. The battery set is charged in the CC mode, and then it is charged in the CV mode while the battery voltage reaches the floating charging voltage.

 

Point 9:

How to select the control parameters? More details should be provided regarding this issue.

Response 9:

Thank you for the valuable comment.

The design guide of the controller is provided in section 6 of the revised paper.

Point 10:

Pictures of the experimental platform should be provided.

Response 10:

Thank you for the valuable comment.

The picture of prototype, Figure 10, has been added in section 7 of the revised paper.

(Detail responses are shown in the pdf file.)

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Accept in present form