A Novel Control Algorithm of the Air Supply Subsystem: Based on Dynamic Modeling of Proton Exchange Membrane Fuel Cell
Round 1
Reviewer 1 Report
I have reviewed an article entitled "A Novel Control Algorithm of the Air Supply Subsystem: Based on Dynamic Modeling of Proton Exchange Membrane Fuel Cell” written by Pengyu Wang et. al.
In this interesting work, the authors proposed a novel second-order active disturbance rejection control (2-ADRC) algorithm to optimize the control of air supply subsystem for Proton Exchange Membrane Fuel Cell (PEMFC).
The authors should improve some recommendations. Such as:
- Line 20 (Abstract): “… compared with PID algorithm and MPC algorithm, …”. I think that is better if the authors use “compared with PID and MPC algorithms, …”
- Line 63 (Introduction): “References [15-17] study the influence of stack pressure on the output power of FCS”. In my opinion, the beginning of the sentence will be more correct in this form “In references [15-17] researchers study the influence of stack pressure on the output power of FCS”.
- Line 70 (Introduction): “Reference [20] further improved the algorithm, coupled fuzzy logic and PID controller, and proposed an AFPID 71 (Adaptive Fuzzy PID) control algorithm”. The beginning of the sentence is repetitive, in my opinion it would be better to modify it by “Tang, X. et al. [20] reported improve of algorithm, coupled fuzzy logic and PID controller, and proposed an AFPID 71 (Adaptive Fuzzy PID) control algorithm”.
- Line 89 (Introduction): “… compared with PID algorithm and MPC algorithm …”. I think that is better if the authors use “compared with PID and MPC algorithms, …”
- Lines 290-292 (Section 2): “The output characteristic curve of PEMFC is shown in Figure 2. In Figure 2(a), with the increasing current density inside the stack”. In my opinion is better if the authors change the beginning of the sentence by “The output characteristic curve of PEMFC is shown in Figure 2. The increasing current density inside the stack (see Figure 2a), ….”
- Line 317-318 (Section 3): …. the PEMFC system are shown in Figure 3. In Figure 3(a), under the fixed current request of 180A …”. In my opinion is better if the authors could be change the beginning of the sentence by “Under the fixed current request of 180 A (see Figure 3a), …”. In the other hand, the authors could be included a space between the value and unit (lines 318 and 321).
- Lines 325-326 (section 3): “the fixed current request, as shown in Figure 3 (b). In Figure 3 (b), the load current is controlled to change from 80A to 420A, the step is 20A…”. The authors could be change the beginning of the sentence by “The load current is controlled to change from 80 A to 420 A (see Figure 3b)” and they could be included a space between the value and unit (line 326).
- Line 332 (section 3): The authors could be change Figure 3, because the quality of figure not is optimum for this publication.
- Lines 333, 388 and 413, Table 2 (section 3): In my opinion the authors could be included a space between all values and units in the text and tables.
Author Response
Dear Reviewer，
We would like to express our sincere appreciation for your careful reading and invaluable comments. In order to effectively improve the quality of the paper, we have made the following modification and explanation to your comment. The amendment made is mentioned below with reference to appropriate paragraph and section of the revised manuscript.
Line 20 (Abstract): “… compared with PID algorithm and MPC algorithm, …”. I think that is better if the authors use “compared with PID and MPC algorithms, …”
[Answer] We have adopted your suggestion and made a revision.
Furthermore, compared with PID and MPC algorithms, …
Line 63 (Introduction): “References [15-17] study the influence of stack pressure on the output power of FCS”. In my opinion, the beginning of the sentence will be more correct in this form “In references [15-17] researchers study the influence of stack pressure on the output power of FCS”.
[Answer] We have adopted your suggestion and made a revision.
In references [15-17], researchers study the influence of stack pressure on the output power of FCS.
Line 70 (Introduction): “Reference [20] further improved the algorithm, coupled fuzzy logic and PID controller, and proposed an AFPID 71 (Adaptive Fuzzy PID) control algorithm”. The beginning of the sentence is repetitive, in my opinion it would be better to modify it by “Tang, X. et al. [20] reported improve of algorithm, coupled fuzzy logic and PID controller, and proposed an AFPID (Adaptive Fuzzy PID) control algorithm”.
[Answer] We have adopted your suggestion and made a revision.
Tang, X. et al. [20] reported improve of algorithm, coupled fuzzy logic and PID controller, and proposed an AFPID (Adaptive Fuzzy PID) control algorithm
Line 89 (Introduction): “… compared with PID algorithm and MPC algorithm …”. I think that is better if the authors use “compared with PID and MPC algorithms, …”
[Answer] We have adopted your suggestion and made a revision.
In Section 3, a 2-ADRC algorithm is proposed and compared with PID and MPC algorithms, …
Lines 290-292 (Section 2): “The output characteristic curve of PEMFC is shown in Figure 2. In Figure 2(a), with the increasing current density inside the stack”. In my opinion is better if the authors change the beginning of the sentence by “The output characteristic curve of PEMFC is shown in Figure 2. The increasing current density inside the stack (see Figure 2a), ….”
[Answer] We have adopted your suggestion and made a revision.
The output characteristic curve of PEMFC is shown in Figure 2. The increasing current density inside the stack (see Figure 2a), the output voltage of the stack decreases and the output power increases.
Line 317-318 (Section 3): …. the PEMFC system are shown in Figure 3. In Figure 3(a), under the fixed current request of 180A …”. In my opinion is better if the authors could be change the beginning of the sentence by “Under the fixed current request of 180 A (see Figure 3a), …”. In the other hand, the authors could be included a space between the value and unit (lines 318 and 321).
[Answer] We have adopted your suggestion and made a revision.
Under the fixed current request of 180 A (see Figure 3a), when the oxygen excess ratio is 2.495, the net power of the fuel cell system reaches the maximum value of 47.30 kw. Therefore, 2.495 is the optimal oxygen excess ratio parameter of PEMFC system at 180 A.
Lines 325-326 (section 3): “the fixed current request, as shown in Figure 3 (b). In Figure 3 (b), the load current is controlled to change from 80A to 420A, the step is 20A…”. The authors could be change the beginning of the sentence by “The load current is controlled to change from 80 A to 420 A (see Figure 3b)” and they could be included a space between the value and unit (line 326).
[Answer] We have adopted your suggestion and made a revision.
The load current is controlled to change from 80 A to 420 A (see Figure 3b), the step is 20 A, …
Line 332 (section 3): The authors could be change Figure 3, because the quality of figure not is optimum for this publication.
[Answer] We sincerely thank you for your valuable suggestion. In the Word version, figure 3 is not clear, but in the PDF version, figure 3 will be optimum for this publication, as shown in the following figure. We will send the original figure of Figure 3 to the Journal and Editor.
Lines 333, 388 and 413, Table 2 (section 3): In my opinion the authors could be included a space between all values and units in the text and tables.
[Answer] We have adopted your suggestion and made a revision.
All changes in the manuscript are highlighted in red type.
Once again, we would like to express our most sincere thanks for your careful reading and invaluable comments.
Author Response File: 
Author Response.docx
Reviewer 2 Report
It is necessary to indicate some assumptions of the study model, for example, to indicate that water condensation or its saturation in the cathode, or two-phase flows, are not being considered.
Gases are considered ideal. The kinetics of electrochemical reactions is first order?
In the introductory section, include references about oxygen diffusion processes (mass transfer in the diffusing and catalytic layers, effective transport coefficients) and how they are affected by changes in pressure.
not incorporating these processes is also an assumption of the study model?
Include a table of the nomenclature of variables and parameters present in the equations. A semi-empirical model for the fuel cell is used. Please indicate why this model was chosen and not another.
Author Response
Dear Reviewer，
We would like to express our sincere appreciation for your careful reading and invaluable comments.
[Comment]: It is necessary to indicate some assumptions of the study model, for example, to indicate that water condensation or its saturation in the cathode, or two-phase flows, are not being considered.
Gases are considered ideal. The kinetics of electrochemical reactions is first order?
[Answer]: We have adopted your suggestion and made a revision, and we have added a text description in Section 2 on page 3.
The PEMFC dynamic model is established under following assumptions: (1) gases conform the ideal gas law and there is no interaction between gas molecules; (2) the water condensation, its saturation or two-phase flow in the cathode are not being considered; (3) the oxygen diffusion are ideal processes, and pressure changes will not affect the effective transport coefficients, mass transfer in the diffusing and catalytic layers.
The electrochemical reaction kinetics of PEMFC is first order.
[Comment]: In the introductory section, include references about oxygen diffusion processes (mass transfer in the diffusing and catalytic layers, effective transport coefficients) and how they are affected by changes in pressure.
not incorporating these processes is also an assumption of the study model?
[Answer]: In this paper, we do not consider in detail the effect of the oxygen diffusion processes (mass transfer in the diffusing and catalytic layers, effective transport coefficients) on the stack reaction, as you have commented, we consider it to be ideal.
[Comment]: Include a table of the nomenclature of variables and parameters present in the equations. A semi-empirical model for the fuel cell is used. Please indicate why this model was chosen and not another.
[Answer]: The mathematical model of PEMFC can be divided into the mechanism model and the empirical model. Although the mechanism model can describe the characteristics and operation of PEMFC from the basic chemical reaction process, the calculation is too complicated. Therefore, a semi-empirical model of dynamic response of PEMFC system was established from a practical point of view on the premise of reasonable assumptions, which can provide reference for the formulation of Energy Management Strategies for FCVs.
All changes in the manuscript are highlighted in green type.
Once again, we would like to express our most sincere thanks for your careful reading and invaluable comments.
Author Response File: Author Response.docx
