Direct Sliding Mode Control for Dynamic Instabilities in DC-Link Voltage of Standalone Photovoltaic Systems with a Small Capacitor

Round 1

Reviewer 1 Report

In this paper, a Direct Sliding Mode Controllers (DSMC) is used for minimizing dc-link capacitor, regulating various components of the PV/BES system. The system's functions are divided into four modes, dependent on energy supply and demand, and battery's state of charge. The testing was carried out on the MT real-time control platform NI PXIE-1071 utilizing Hardware-In-Loop experiments and Matlab/Simulink.

My main comment is on the presentation of technical parts, especially the propositions. I recommend presenting these propositions in a standard format.

It is not clear how (14)-(17) are obtained.

More importantly, in line 248, it has been claimed that there is a specific time limit for convergence. Please elaborate on this more and present this time limit.

Please improve the quality of Figures 5 and 8.

Please carefully check the paper for typos, especially in the abstract there are some sentences starting with lower-case words. Moreover, the sentences are very long which makes them hard to follow.

 

Author Response

Pleas see the Responses to Reviewer in file attached below.

many thanks 

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper presents a novel technique for enhancing electricity quality through the invention and implementation of a photovoltaic/battery energy storage (PV/BES) that provides uninterruptible power supply for local nonlinear loads operating in multimode mode. The introduction is quite poor and focused mainly on you topic. A open description of risk and benefits, barrier and opportunities of photovoltaic systems could be improve the scientific approach. To this purpose, the paper https://doi.org/10.3390/su13095246 could be useful for giving an overview of risks and benefits of pv systems. The aim is clear despite it is not discussed in a proper section. The novelty of you invention compared to other is not considered in a specific way. Improve this part to demonstrate the gap in the literature and the innovative value of you research. The technical description of your work is well motivated and referenced. In the conclusion show better the main outcomes of the research and their utility for the scientific community.

Author Response

Pleas see the Responses to Reviewer in file attached below.

many thanks 

Author Response File: Author Response.pdf

Reviewer 3 Report

The article deals with current issues of network stability with a connected photovoltaic energy source. I think that the article needs a minor revision (see comments). After this revision, I recommend it for publication.

Comments:

- Connecting each device to the network affects its stability (inverters as well as rotary machines). I think the following article should be mentioned in the references - Petrík, T., Daneček, M., Uhlíř, I., Poulek, V., Libra, M. Distribution Grid Stability - Influence of Inertia Moment of Synchronous Machines. Applied Sciences, 2020, 10(24), Article ID 9075, ISSN 2076-3417, doi:10.3390/app10249075. There is also talken about connecting the PV power plant to the network.

- The parameters of a photovoltaic power plant also depend on the temperature. Maybe the authors would find inspiration in the article  doi: 10.1109/JPHOTOV.2021.3108484 as well.

- Ihroughout the text, the symbols of the physical quantities should be written in italica font, units in standard font. This is not strictly adhered to. See for example Figs. 9÷16, lines 421, 477, …   There must be gap between value and unit throughout the full article. I think that some values are missing units and so the physical meaning is lost, se efor example lines 415, 421,

- Line 405: 2 must be as superscript and there must be a gap behind 1000 (1000 W.m^-2).

- Figs. 11, 12:  I, V, P shoud be written on the vertical axis in italica font (quantities).

- Seconds should be signed by small „s“ in figures, line 477: t = 0.03 s and t = 0.12 s.

- Lines 457, 465:  better to use the symbol „%“.

Author Response

Pleas see the Responses to Reviewer in file attached below.

many thanks 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have addressed my comments.

Reviewer 2 Report

Thank you very much for considering my suggestions