Stability Analysis and Design of Variable Step-Size P&O Algorithm Based on Fuzzy Robust Tracking of MPPT for Standalone/Grid Connected Power System

Round 1

Reviewer 1 Report

The structure of the manuscript is good and the authors have described the process well. The introduction section is useful and the other sections of the article are easy to understand. This paper uses a combination of several optimization methods for MPPT. ACO method was used to achieve the optimized value for coefficients of PID controller, and MPPT did by the P&O method. Still the following comments needs to be addressed.

1)      The novelty of the paper is weak. I think the main novelty is using the various step size for P&O. Apart from this, other works are not new and have been done in abundance in other papers.

2)      All steps are performed at the DC voltage level. It would be better to analyze the AC output despite these processes. That is, instead of using a DC to DC converter, an inverter or micro-inverter was used.

3)      In section 4, the stability analysis of the system has been analyzed. What is the main purpose of this section? Is it just a statement that the system is stable? Or is it to say that there is a more stable margin in this method?

4)      What is the meaning of efficiency in this method? What is the formula based on which the efficiency is obtained? What are the input and output powers?

5)      In figure 12 Temperature must use real-time data.

 

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Reviewer 2 Report

The paper demonstrates the ACO-P&O tuning method for a PID controller in MPPT algorithm. The proposed method is validated and compared to other tuning methods with simulations. Although the results show an improved response of the PID controller, my question remains.   

(1) The role of ACO in this article is to tune the PID controller to the optimal parameters yet it is unclear why these parameters can't be obtained by proper conventional tuning methods. Results in Section 3 have not states any assumption made in comparison. 

(2) Stability analysis in section 5 demonstrates the transfer function of the system but the conclusion points to the efficiency of 3 parameter sets. It didn't support the claim of ACO superiority in this aspects.

 

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Reviewer 3 Report

The paper entitled Stability analysis and design of variable step-size P&O algorithm for efficient tracking of MPPT under changing weather conditions deals with RES issues. The paper presents a methodology for controlling the operation of PID controller depending on the difference between the generated power of PV power plant and its rated power. Depending on the size of the error the value of the control step is also changed. The developed algorithm can operate online and offline.  In this paper, a probabilistic swarm optimization technique based on ACO ant movement is used. The algorithm has been proposed to track MPPT. The work addresses a very important and timely topic.

The weakest part of the paper is the literature review. It does not indicate the scientific problem. It contains examples of solutions to the MPPT tracking problem. Their disadvantages or limitations are indicated very generally. The methods proposed in the paper are not an original approach. I propose in the literature review to make a critical analysis of the existing works and indicate what will be novelty of the work. Please consider a tabular summary of known algorithms for MPPT search and state their advantages and disadvantages.
How the complexity was evaluated of the system in Table 1.
Please refer to other works (e.g. K. Sundareswaran, V. Vigneshkumar, P. Sankar, S. P. Simon, P. Srinivasa Rao Nayak and S. Palani, "Development of an Improved P&O Algorithm Assisted Through a Colony of Foraging Ants for MPPT in PV System," in IEEE Transactions on Industrial Informatics, vol. 12, no. 1, pp. 187-200, Feb. 2016, doi: 10.1109/TII.2015.2502428. or
https://doi.org/10.1016/j.egyr.2022.03.175 or https://doi.org/10.1016/j.matpr.2020.06.20) and demonstrate what is new about the work. Of the literature items, only one is from 2020, the others are older.  Please update.  Please justify in the body of the paper its relation to sustainable development.

The methodology of the work is presented in a clear and readable manner.

The presentation of the research results does not raise objections. There is a lack of explanation for the symbols used e.g. Pp, Kp, Ki, Kd etc. In figure 16 what do the bars in the same colour represent?
The paper lacks a more extended comparative analysis of the developed algorithm to other literature items.

The conclusions should be expanded. Many interesting analyses have been done and the conclusions are very general.

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Reviewer 4 Report

 

The article presented for review proposed an ant colony optimization-based Perturbation and Observation (P&O) for maximum power point tracking (MPPT) to improve the response of P&O under rapid changing environmental conditions. The performance of the proposed technique is evaluated by comparing with Genetic algorithm-based technique and P&O algorithm.

In this regard the authors should consider the following comments:

·       lines 167 - 187 please standardise the font size (larger than the rest of the article).

·       lines 254: Table 3 (text bold) - please check the description.

·       Please ensure that all symbols used in the formulas and figures as well as abbreviations are explained in the text.

·       Numbering of figures should be corrected. Figure 6 is  double-used: in line 206 and in line 242.

·       Figures 5 and 12 are not referenced in the text.

·       The units given in the figures should be consistent: and not as in Figure 14 (watts).

·       In figure 8 the legibility and size of the units should be improved.

·       Please mention DOIs in the references where it is possible.

 

 

Author Response

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