Double-Loop Controller Design of a Single-Phase 3-Level Power Factor Correction Converter

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thanks for submitting your work for possible publication.

1) Page 1 - Line 29. Rewrite to address that it is related to the control circuitry.

2) Line 33 - Specify that the usage of dq components is one of the possible strategies.

3) Line 55-57: It is important to mention that other strategies as Notch-filter, lead-lag were also applied and are well-known in literature to deal with the 120 Hz. Please, improve the literature review. What are the disadvantages of the aforementioned techniques and the drawbacks the authors would like to solve or contribute to?

4) Lines 75-77 and 83-85 are duplicated. Please, remove one.

5) Literature has already presented APF filters. So, please add references in lines 147-149.

6) How the modeling can be applied to the full-duty range? Is it applied using a small-signal analysis? Observe that.

7) BSF (eq. 12) is already used in literature. Please, add references.

8) A mathematical procedure instead of direct use of SISOTOOL would be better for archival values.

9) Figs. 9, 10, 14, and 15 lose their quality. Verify it. Using Fig. 10 as an example, it is important to show details of the curves. A detail at 0.4ms with 2 or 3 current cycles can improve the paper's quality. For the other results, waveform details would be important.

10) What are the PF and DHT of the current (in the experiments)? A FFT analysis can improve the analysis of the paper. 

11) It is important to highlight the paper's real contribution to literature. 

Author Response

Thanks for the compensive review. 

I corrected every comments you mentioned.

The answers are attached in the file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper proposes a novel double-loop controller design technique that employs a band-stop filter and MATLAB SISOTOOL optimization method. It enhances the modeling and control of three-level power factor correction (PFC) converters, addressing the steady-state error issues under 120 Hz voltage ripple found in traditional methods. The effectiveness and reliability of this approach are demonstrated through PSIM simulations and practical experiments.

 

Regarding the content of the paper, I have the following remarks:

 

1.     What are the specific parameters and design methods of the band-stop filter used in the process? How is it integrated into the double-loop controller?

2.     What specific assumptions and boundary conditions are involved in the modeling using the state-space equation? How does this modeling method apply to the full duty range?

3.     How are the initial parameters selected and set when using MATLAB SISOTOOL for automatic tuning?

4.     What specific parameters and conditions were used in the PSIM simulation to evaluate the effectiveness of the proposed double-loop controller? How do these parameters compare to real-world conditions?

5.     How does the performance of the proposed double-loop controller compare with existing methods in terms of voltage ripple rejection and overall efficiency? Are there specific metrics or benchmarks used for this comparison?

6.     The text in Picture 7 is not clear, the background of the waveform in the experimental part is not clear, and the waveform has jagged edges.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Some of the sentences in this article contain grammatical errors, so please proofread carefully before submitting!

Author Response

Thanks for the compensive review. 

I corrected every comments you mentioned.

The answers are attached in the file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Very interesting paper on topology of three-level PFC converter. My general assessment of the article is very good, but I noticed some minor flaws that I think could be corrected:

1. The PFC converter can operate at both 50 Hz and 60 Hz grids. However, the paper mentions that only 60 Hz or 120 Hz components are problematic. In my opinion, it is better to mention a 100 Hz/ 120 Hz component, showing that the second harmonic is problematic in PFC converters.

2. The text between lines 82 - 89 is repeated two times. 

3. In lines 101-102, there is a table with no number. You should use MDPI format for captioning the table. The operation times of States 2, 3, and probably 4 have typos. For example, the operation time of state 2 should be dTs, not (1-d)Ts. The equations (5) and (6) however are correct. 

4. Figures 9-11 are blurry and difficult to interpret. The values ​​on the axes are illegible 

 Thank you

Author Response

Thanks for the compensive review. 

I corrected every comments you mentioned.

The answers are attached in the file.

Author Response File: Author Response.pdf