Load Power Oriented Large-Signal Stability Analysis of Dual-Stage Cascaded dc Systems Based on Lyapunov-Type Mixed Potential Theory

Round 1

Reviewer 1 Report

The paper addresses large-signal stability issue of the dual-stage cascaded dc systems from a load power standpoint. The system is modeled using the discrete-mapping technique, and the explicit form large-signal stability boundary in terms of load power is then obtained by using Lyapunov-type mixed potential theory. 

Overall paper is well organized and well presented. However:

-        In the abstract, the results should be quantified also.

-        It is recommended to emphasize the contributions of the paper at the end of the introduction.

-        Please check, there are some units that were separated from their numbers, review and adjust so that they keep together.

-        Please provide adequate references for equations given in all sections.

-        The diagrams of this paper need to be improved.

-        Currently, there is a high penetration of wind and solar energy sources in power systems around the world, the method proposed by the authors does not seem to show the advantages of using this type of dual-stage cascaded dc systems and its effect on the integration of renewable energies in an electrical power system.

Author Response

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Reviewer 2 Report

This paper addresses large-signal stability issue of the dual-stage cascaded dc systems from a load power standpoint. And the effectiveness of the load power stability boundary is validated by both circuit-level simulation and experimental results.

My comments are given in detail as follows.

1. What are the gaps in the existing literature that covers by the proposed approach. What are the advantages of the proposed approach compared to the existing load power oriented large-signal stability analysis methods? Additionally, contributions of the paper compared to the numerous works presented so far are not clear. To recap, further clarification is required in the Introduction section.

2. As we know, Lyapunov-type mixed potential theory is a basic method for the power oriented large-signal stability analysis. What are the different from the proposed method to other potential theory, such as Brayton Moser mixed potential theory or other published Lyapunov-type mixed potential theory. What are the advantages and disadvantages of their analysis performance.

3. What do different colors represent in Figure 5?

4. In line 193, The equation reference is missing a number.

5. In the experimental validations, what is the sampling frequency of output voltage signals? How about the current results?

6. The conclusion should be more specific and different from the abstract.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

*"Under the border collision bifurcation, the nonlinear dynamical behaviours of the system may change dramatically such as a direct jump from a periodic orbit to a chaotic orbit. The essential cause of this phenomenon is the bounded duty cycle of the switching converter."

Researchers should propose solutions for the bounded duty cycle of the switching converter.

*The result should be explain in more detail.

*The results should be compared with the literature.

*Conclusion section should be given in more detail.

 

Author Response

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Reviewer 4 Report

In this paper, The system is modeled using the discrete-mapping technique. The explicit form large-signal stability bounboundaries terms of load power are then obtained using Lyapunov-type mixed potential theory. The deduced boundary is highly consistent with the bifurcation diagram analysis results and  Jacobian matrix-based analysis. Moreover, the effectiveness of the load power stability boundary is validated by both circuit-level simulation and experimental results. The main idea is of interest but the following comments must be improved: 

1. Update the abstract section with the significant contribution involving the numerical assessment of the criteria you presented. 

2. Introduction section is written in a very compact way. Add critical issues and the research gap and contribution. Don't use many references without criticism of the previous work correctly.  Please, see lines 35 and 36 for a sample of this issue.

3. Long sentences must be avoided. 

4. Update the state model with the disturbance mode. 

5. Show the stability and robustness evaluation of the proposed method

6. Extend the experimental and simulation results for different faults with an assessment of the simulation model and experimental records. 

7. Conclusion section is very limited. 

8. similarly complete all References data. see for example Ref. 15.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

It seems that you have made a detailed article revision.

 

Author Response

Thanks again for your timely handling and hard work.

Reviewer 4 Report

No other comments. 

Author Response

Thanks again for your timely handling and hard work.