Modeling and Control of a Phase-Shifted Full-Bridge Converter for a LiFePO₄ Battery Charger

Round 1

Reviewer 1 Report

There is plenty information about the accuracy of the controller in the paper, but more interesting would be practical profits and practical results taken in a real life system.

Author Response

Authors appreciate the corrections and hope that the answers enlisted below in this document fulfill the expectations. We considered every suggestion as a valuable opportunity to improve and enrich enormously our work. Therefore, we have intended to be as punctual as we could to attend the decision of Major Revisions. Reviewer observations are highlighted using bold black font, our replies using blue font and changes in existing sentences have been written in italic font.

Reviewer 2 Report

 In this article the authors present a ARX model of a phase-shifted full-bridge 4 (PSFB) converter is obtained and then present model based classical controllers. The authors experimentally demonstrate the closed loop performance of the proposed controllers and its comparison with the simulations based on the developed model. Below are my comments:

1. The authors use a black box system identification approach. They have not provided detailed reasoning behind this choice. Why is first principles modeling not used?
2. The authors use a 3rd order ARX model. However, they did not provide any explanation on how they arrived at the 3rd order model. Why nor a lower order and why not a higher order needs to be explained. Does the natural frequencies of the identified model match that of the actual system? Overall, only comparing the model performance against a step input is not sufficient to conclude on model accuracy. The authors should comment on how does the frequency response of the actual system compare to that of the model. 
3. The reference signal in Fig 9 (a) and (b) are different. Is this an error in plotting? Please clarify this. It is difficult to compare the controller responses in the two figures. Ideally, having the reference and the responses of the closed loop system of both controllers in the same plot with enable a better comparative study for the reader. You may also consider some error metric and quantify the performance of the two controllers on that error metric. 
4. The article needs to be reviewed with an English language editor. 

Author Response

Authors appreciate the corrections and hope that the answers enlisted below in this document fulfill the expectations. We considered every suggestion as a valuable opportunity to improve and enrich enormously our work. Therefore, we have intended to be as punctual as we could to attend the decision of Major Revisions. Reviewer observations are highlighted using bold black font, our replies using blue font and changes in existing sentences have been written in italic font.

Reviewer 3 Report

The paper presents studies regarding the modeling, simulation and control of a phase-shifted full-bridge converter for a dedicated battery charger. There are performed validations of the simulation results on experimental setup.

The plant modeling is done by using ARX model. Did you consider to use also other type of models such as ARMAX, ARIX, AR, ARI, ARIMA or MA’s? It would be interesting to see the impact of model type on the simulation results.

The simulation results are interesting.

How was the PI/PID controller tuned? Through successive iterations or Ziegler–Nichols, etc?

Indeed, the PID controller is not suitable for this kind of applications.

Of course, it would be interesting to see a comparative study with other types of controllers, but this would certainly exceed the goal of the present manuscript.

I positively appreciate that the simulation results were validated on an experimental bench.

The conclusions should be extended for a better highlighting of the authors contributions versus other similar topic studies.

Minor English language improvements can be done.

Author Response

Authors appreciate the corrections and hope that the answers enlisted below in this document fulfill the expectations. We considered every suggestion as a valuable opportunity to improve and enrich enormously our work. Therefore, we have intended to be as punctual as we could to attend the decision of Major Revisions. Reviewer observations are highlighted using bold black font, our replies using blue font and changes in existing sentences have been written in italic font.

Round 2

Reviewer 2 Report

I am satisfied with the response by the authors to my comments. The article is much better now from the modeling perspective and will provide inspiration to other researchers to apply black box models.