Realization of Low-Voltage and High-Current Rectifier Module Control System Based on Nonlinear Feed-Forward PID Control
Round 1
Reviewer 1 Report
Comments:
- The paper describes that there are several parameters that should be tuned, but the paper does not provide information on how they are calculated in Section 3. Also, the controller parameters (for both direct and nonlinear feedforward control) are not given, and the mathematical model of the entire closed-loop system (for both direct and nonlinear feedforward control) is also not given. Simulink schemes are shown in some figures, but they are not helpful as the reader cannot repeat the results given in the manuscript. The authors should at least publish the entire Simulink models online with all the parameters of the process and the controllers. Otherwise, there is no way to replicate the results.
- In line 144 it says: "To realize a control without static error, a nonlinear PID control with feedforward is used.". No control error at steady state can be achieved with any controller that contains an integral component, such as PI or PID controllers. It is not clear why a nonlinear FF PID controller should be used to achieve this.
- Line 158 states, "The feedforward control consists of adding the tracking signal v1 from the tracking differentiator (I) to the control terminal u(t) to form an open loop control. This is not a closed-loop control, but a classical feedforward control (2-DOF control). Figure 3 shows a classical 2-DOF controller achieved by different transfer functions from setpoint and process output signal.
- Why are the values x1 and x2 used in section 2.3.1 instead of v1 and v2 in section 2.3.2?
- Check the font size (e.g. line 265).
- Some figures are missing, e.g. figures 10 and 16.
- Figures 19 and 20 should have the same time span, for example between 4.5 and 6 seconds. The same is true for the real experiment in figure 26.
- In the real experiment the currents are much more wavy (Figure 25) than in the simulations.
- The paper should definitely be proofread by a native English speaker, as some of the sentences are not clear. Also, many words are hyphenated, such as recti-fication, atten-tion, prob-lem, para-metric, etc.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper presents a novel low-voltage and high-power rectifier module control strategy based on nonlinear feed-forward PID control for application in low-voltage and high-current permanent magnet synchronous generator (PMSG). Such strategy should be characterised by robustness, high flexibility, rapid adaptation and fast response.
The topic of the paper is interesting and well aligned to the aims and scope of the Journal.
The analysis of the state of the art, which is provided in the introductory section, is quite superficial (with many lump references) and the motivations behind the proposed work are not fully clear. The authors should elaborate more deeply this aspect.
Section 2 starts with the description of the PMSG studied in the present work, which is stated to be innovative with respect to a previous one, but neither reference no descriprion of this previous PMSG is provided. Therefore, it is difficult to assess the elements of novelty. The bases and background from which this work was generated are not explained by the authors, although this should be the right section to introduce them.
The decoupling control strategy is very synthetically described. The symbols adopted in the equations are reported in a different format in the text, and this generates confusion in the reader. The description of the Nonlinear feed-forward PID control algorithm is overall clear, but Figure 3 deserves a deeper explanation in the text.
The presentation of the simulation results is comprehensive and well detailed. The comparison with the experimental tests is overall adequate and the achieved conclusions are well supported by the provided data.
From the formal point of view, there are many words, which are split in two parts in a useless and erroneous manner. This must be corrected.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
An interesting article showing a new PID control.
- A rectifier is also commented in the studied power supply system. The only hint about it is in the simulation file in matlab. It is good to comment a little about it. When the current changes from 150A to 300A, the change in the voltage drop across the transistors also has an effect. To say how this fact is reported in the regulator.
- Are there any "-" left in the text from the transfer of words in two lines (for example, page 1, line 32, line 35, line 36, line 38; page 2 line 46, line 57; page 3 line 112 and others). Please review it carefully.
- Commenting on the result from page 3 figure 25, to comment in more detail on the current fluctuation and its difference with the simulation result.
In conclusion, Interesting research and I propose that it be published.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors thoroughly revised the paper according to the suggestions provided by the reviewers. The paper has drastically improved and now it is suitable to publication.
