A Novel Reverse Combination Configuration to Reduce Mismatch Loss for Stratospheric Airship Photovoltaic Arrays

Round 1

Reviewer 1 Report

The manuscript presents a new approach for photovoltaic array configuration of airships in stratospheric orbit.
The aim of the manuscript is to propose a novel reverse combination configuration method to reduce in-flight mismatch losses.
Steerable airships such are ideal for long-duration missions. The challenge is to provide stable electrical power for propulsion, avionics and mission target systems.
Most often, solar systems are used for power supply. A novel reverse combination configuration is proposed to reduce in-flight mismatch losses. Simulations were made taking into account real flight conditions and a comparison of the proposed methodology with classical series-parallel and total cross-tied configurations is made.
In the manuscript, a survey of existing methodologies is made and a model of the output power of the photovoltaic system built on stratospheric airships is created.
In addition to the advantages in the conclusion section, it would be useful for the authors to comment on the disadvantages of the proposed method.
In this way, a complete picture of its qualities, capabilities and application limitations will be obtained.
Many symbols and abbreviations are used in the text, I recommend that authors add a list of symbols used at the beginning or end of the manuscript.
The results of the conducted research were analyzed and discussed. In conclusion, a new method for reconfiguring the photovoltaic array to achieve higher output power is presented.
References cited are relevant and up-to-date.
The figures are clear and readable, the tables are comprehensive.

In addition to the advantages in the conclusion section, it would be useful for the authors to comment on the disadvantages of the proposed method.
In this way, a complete picture of its qualities, capabilities and application limitations will be obtained.

Many symbols and abbreviations are used in the text, I recommend that authors add a list of symbols used at the beginning or end of the manuscript.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Congrats for your effort.

Literature review can be improved. References can be presented with more details and especially those which concern similar case studies. Furthermore can be extended with background of stratospheric airships and use of pv technology in airships.

Line 54 describe  these typical conditions.

Lines 94-104 is presented contribution and contents of this paper. Clear up the objectives/ goals and reason that stress novelty.

Line 231 R_S,R_SH which values selected in  simulation procedures.

Line 241explain why these conditions are typical. This argument based on literature?

Line 326 “real flight conditions” explain this definition what is included in this phrase. There are similar studies that use this term?

Table 2 is presented “PV module” characteristics. You could provide information about size of module. Which are conditions when  Maximum power is achieved? For example in conventional PV panel these values are referred on STC conditions. Explain these values.

In last row of table 2 is presented “parallel number of PV values I_sc”. Its value is like a temperature coefficient.

Figure 9-10 presents mismatch loss power and power loss rate for the “4 conditions” . Which are the temperature conditions in these state.

Figure 12 wind speed is based on historical data?

Peak power in results concerns DC power? There is any inverters or DC – DC converters? Mismatch in converters have been take into account. Give some information for the PV system of airships.

In abstract is referred  that simulations are conducted for a whole irradiance period however this fact are presented only four days of December.

You can add grid lines in your Figures in order to be more clear.

An abbreviation list could be useful because of the large number of acronyms.

Conclusion section, clear up which of the objectives/goals are achieved and describe the weaknesses of your approach. Propose future work.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The authors in the paper focus on comparing the new arrangement of PV modules and their comparison with the standard arrangement. The authors should address the following comments in the article.

1. It is necessary to describe what scientific contribution your work results have.

2. In fig3 describe R serial R sh and what represent Cp parameter ?

3. On table 2 are parameters of PV module. Autors describe paralele connect PV modules with short circuit current 67,36 A. So for parallel connections the short circuit current must be to more. It is ok for connection in the practice ?

4. Why did the authors choose such a rearrangement of PV modules? Was it random? A more detailed analysis of this methodology is lacking. 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have also commented on the shortcomings of the proposed method in the conclusion section.
The authors intend to continue in future work to conduct ground experiments, to evaluate the performance of the proposed RC configuration and estimate the additional weight.
It will also apply this configuration to other solar-powered aircraft, such as solar drones and high-altitude balloons.
Many notations and abbreviations are used in the text, the authors have added a list of used notations at the beginning of the manuscript.
In conclusion, I accept the corrections made by the authors as comprehensive.

Reviewer 2 Report

Congrats for your effort.

Reviewer 3 Report