Speed Control with Indirect Field Orientation for Low Power Three-Phase Induction Machine with Squirrel Cage Rotor

Round 1

Reviewer 1 Report

The paper deals with Speed Control with Indirect Field Orientation for Low Power Three-Phase Induction Machine with Squirrel Cage Rotor. 
According to the reviewer, the paper is not worth publishing at Machines Journal, but some corrections are needed and then the paper can be accepted for publication in the journal.
While the authors have made considerable research effort, 
the presentation of the paper and the results must be proved. 
Additionally make the following corrections to the manuscript:

Comment 1
Line 3
a three-phase induction machine (MIT) of the
replace
a Three-phase Induction Machine (MIT) of the

Comment 2
Line 5
proportional-integral (PI) type
replace
Proportional-Integral (PI) type

Comment 3
Line 17
in industry in applications
The authors must restate (two in).

Comment 4
Line 35
The authors must restate (it is not good to use the word we)

Comment 5
Lines 50 - 51
as digital signal
processors (DSPs) and digital signal controllers (DSC) [6].
replace
as Digital Dignal
Processors (DSPs) and Digital Signal Controllers (DSC) [6].

Comment 6
Line 55
indirect oriented field control strategy (IFOC).
replace
Indirect Oriented Field Control strategy (IFOC).

Comment 7
Line 63
space vector pulse width modulation (SVPWM).
replace
Space Vector Pulse Width Modulation (SVPWM). 

Comment 8
Line 78
2. Auxiliary source power supply circuit breaker;;
replace (delete one ;)
2. Auxiliary source power supply circuit breaker;

Comment 9
Lines 92 - 93
VSI (Voltage Source Inverter), powered
by a voltage source, and CSI (Current Source Inverters)
replace
Voltage Source Inverter (VSI), powered
by a voltage source, and Current Source Inverters (CSI)

Comment 10
Lines 106 + 109 
First the authors mention Reference [8] in the text and then [7].
According to the journal's instructions:
References: References must be numbered in order of appearance in the text 
(including table captions and figure legends) and listed individually at the end of the manuscript.   

Comment 11
Equation 1
The authors must check if the equation 1 is correct.
V2nom - (0.9Vnom)2  
why not 0.19V2?

Comment 12
1. Introduction
The authors use 6 references in Introduction.
The authors must increase the references papers in section 1. 

Comment 13
Line 145
value (311 Vdc)
The authors must explain what 311 means?

Comment 14
Line 187
an LED (Light Emitting Diode) 
replace
a Light Emitting Diode (LED) 
The authors must check the spelling and typographical errors.

Comment 15
Line 195
with TTL (Transistor-Transistor Logic) logic level,
replace
with Transistor-Transistor Logic (TTL) logic level,

Comment 16
Figure 7
The authors must increase the visibility of the Figure 7.

Comment 17
Page 8 and 15
Delete the space in the page end.

Comment 18
Figure 8
The authors must increase the visibility of the Figure 8.

Comment 19
Line 313
In field oriented control (FOC),
replace
In Field Oriented Control (FOC),
 
Comment 20
Lines 314 - 322
The reference [18] is missing.
The authors must insert the reference [18].

Comment 21
Lines 335 - 336
The authors must insert numbering for Lines 
The discription for Te must insert near the equation 5.

Comment 22
Equations
The authors must not use at the end of the equations . or ,

Comment 23
No numbering
The equation (9) allow you ti
calculate the reference voltage level

The authors must check for spelling and typographical errors.

Comment 24
Figure 21
Current (A) Iq: There is no Reference Iq (no black color)
Speed (RPM): There is no Simulated rotor speed (no green color)

Comment 25
Table 6
The authors must explain the difference between Simulated Value (0%) vs Experimental Value (27%) for Overshoot (Mp). 

Comment 26
Figure 22
Current (A): There is no Reference Id (no black color)

Comment 27
Figure 23
Current (A): There is no Reference Id (no black color)

Comment 28
Table 7
The authors must explain the difference between Simulated Value (0%) vs Experimental Value (40%) for Overshoot (Mp). 

Comment 29
Line 416
The authors must restate (it is not good to use the word we)

Comment 30
Table 8
The authors must explain the difference between Simulated Value vs Experimental Value for Overshoot (Mp). 

Comment 31
References
According to the instructions
https://www.mdpi.com/journal/machines/instructions
References should be described as follows, depending on the type of work:

Journal Articles:
1. Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.
The authors must change the format of the Volume (Italics)

Comment 32
Increase the number of the reference papers including (primarily) from MDPI Journals
The authors use 0 paper from Machines Journal / 0 MDPI Journals / 22 papers from journals (References)
Τhe number for papers from Machines journal
is considered insufficient (in reviewer's opinion).

Author Response

Response to Reviewer 1 Comments

Point 1:

Line 3

a three-phase induction machine (MIT) of the

replace
a Three-phase Induction Machine (MIT) of the

Response 1: The initial letters of the abbreviation (MIT) have been changed to capital letters.

Point 2:

Line 5
proportional-integral (PI) type
replace
Proportional-Integral (PI) type

Response 2: The initial letters of the abbreviation (PI) have been changed to capital letters.

Point 3:

Line 17
in industry in applications
The authors must restate (two in)

Response 3: The second (in) was removed and the word "industry" replaced with "industrial" in order to make the sentence clearer.

Point 4:

Line 35
The authors must restate (it is not good to use the word we)

Response 4: The word "we" was removed and the sentence was rephrased.

Point 5:

Lines 50 - 51
as digital signal
processors (DSPs) and digital signal controllers (DSC) [6].
replace
as Digital Signal
Processors (DSPs) and Digital Signal Controllers (DSC) [6].

Response 5: The initial letters of the abbreviation (DSP) and (DSC) have been changed to capital letters.

Point 6:

Line 55

indirect oriented field control strategy (IFOC).
replace
Indirect Oriented Field Control strategy (IFOC).

Response 6: The initial letters of the abbreviation (IFOC) have been changed to capital letters.

Point 7:

Line 63
space vector pulse width modulation (SVPWM).
replace
Space Vector Pulse Width Modulation (SVPWM).

Response 7: The initial letters of the abbreviation (SVPWM) have been changed to upper case.

Point 8:

Line 78
2. Auxiliary source power supply circuit breaker;;
replace (delete one ;)
2. Auxiliary source power supply circuit breaker;

Response 8: The excess ";" has been removed.

Point 9:

Lines 92 - 93
VSI (Voltage Source Inverter), powered
by a voltage source, and CSI (Current Source Inverters)
replace
Voltage Source Inverter (VSI), powered
by a voltage source, and Current Source Inverters (CSI)

Response 9: The abbreviation (VSI) and (CSI) have been placed after the respective term.

Point 10:

Lines 106 + 109 
First the authors mention Reference [8] in the text and then [7].
According to the journal's instructions:
References: References must be numbered in order of appearance in the text 
(including table captions and figure legends) and listed individually at the end of the manuscript.

Response 10: The numbering of the references was organized according to the sequence of citation in the text.

Point 11:

Equation 1
The authors must check if the equation 1 is correct.
V2nom - (0.9Vnom)2  
why not 0.19V2?

Response 11: The expression as it was presented in the text was in expanded form. Thus, it was simplified.

Point 12:

1. Introduction
   The authors use 6 references in Introduction.
   The authors must increase the references papers in section 1. 

Response 12: References have been added to the introduction that address topics relevant to the drive and control of induction machines.

Point 13:

Line 145
value (311 Vdc)
The authors must explain what 311 means?

Response 13: The voltage at the input of the full bridge diode is 220 Vrms. Thus the DC link voltage at the output of the rectifier circuit is equivalent to the peak input voltage. The equation below shows the calculation of the DC link voltage:

Vout = Vin*sqrt(2)

Vout = 220*sqrt(2)

Vout = 311 Vdc

Point 14:

Line 187
an LED (Light Emitting Diode) 
replace
a Light Emitting Diode (LED) 
The authors must check the spelling and typographical errors.

Response 14: The abbreviation (LED) has been placed after the respective term.

Point 15:

Line 195
with TTL (Transistor-Transistor Logic) logic level,
replace
with Transistor-Transistor Logic (TTL) logic level,

Response 15: The abbreviation (TTL) has been placed after the respective term.

Point 16:

Figure 7
The authors must increase the visibility of the Figure 7.

Response 16: The figure has been adjusted.

Point 17:

Page 8 and 15
Delete the space in the page end.

Response 17: The extra spacing has been removed from the text.

Point 18:

Figure 8
The authors must increase the visibility of the Figure 8.

Response 18: The figure has been adjusted.

Point 19:

Line 313
In field oriented control (FOC),
replace
In Field Oriented Control (FOC),

Response 19: The initial letters of the abbreviation (FOC) have been changed to capital letters.

Point 20:

Lines 314 - 322
The reference [18] is missing.
The authors must insert the reference [18].

Response 20: The reference has been added to the text.

Point 21:

Lines 335 - 336
The authors must insert numbering for Lines 
The discription for Te must insert near the equation 5.

Response 21: The description of the electromagnetic torque was entered next to equation 5.

Point 22:

Equations
The authors must not use at the end of the equations . or ,

Response 22: The scores at the end of all equations were removed.

Point 23:

No numbering
The equation (9) allow you ti
calculate the reference voltage level

The authors must check for spelling and typographical errors.

Response 23: The sentence has been rephrased for better understanding.

Point 24:

Figure 21
Current (A) Iq: There is no Reference Iq (no black color)
Speed (RPM): There is no Simulated rotor speed (no green color)

Response 24: The chart has been updated to make it possible to see all the information.

Point 25:

Table 6
The authors must explain the difference between Simulated Value (0%) vs Experimental Value (27%) for Overshoot (Mp). 

Response 25: The explanation for the diverging overshoot values has been added to the text.

The overshoot present in the experimental i_d signal is related to simplifications adopted for the current controller design. The closed-loop transfer function of the current plant presents a zero. This zero was disregarded to calculate the PI controller gains. Thus, in the real system, this zero will cause a proportional overshoot for fast responses, but the settling time will be preserved.

Point 26:

Figure 22
Current (A): There is no Reference Id (no black color)

Response 26: The chart has been updated to make it possible to see all the information.

Point 27:

Figure 23
Current (A): There is no Reference Id (no black color)

Response 27: The chart has been updated to make it possible to see all the information.

Point 28:

Table 7
The authors must explain the difference between Simulated Value (0%) vs Experimental Value (40%) for Overshoot (Mp). 

Response 28: The explanation for the diverging overshoot values has been added to the text.

The overshoot present in the experimental i_q signal is related to simplifications adopted for the current controller design. The closed-loop transfer function of the current plant presents a zero. This zero was disregarded to calculate the PI controller gains. Thus, in the real system, this zero will cause a proportional overshoot for fast responses, but the settling time will be preserved.

Point 29:

Line 416
The authors must restate (it is not good to use the word we)

Response 29: The word "we" has been removed from the text.

Point 30:

Table 8
The authors must explain the difference between Simulated Value vs Experimental Value for Overshoot (Mp). 

Response 30: The explanation for the diverging overshoot values has been added to the text.

The overshoot signal for the speed loop with different speed profiles shows little difference from the performance specifications. The closed-loop of the speed controller has a zero that was disregarded for the calculation of the controller gains. In the experimental environment, this zero contributes to the divergence of the peak speed from the simulated speed signal.

Point 31:

References
According to the instructions
https://www.mdpi.com/journal/machines/instructions
References should be described as follows, depending on the type of work:

Journal Articles:
1. Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.
The authors must change the format of the Volume (Italics)

Response 31: The references have been reviewed and the necessary adjustments have been made according to the link instructions.

Point 32:

Increase the number of the reference papers including (primarily) from MDPI Journals
The authors use 0 paper from Machines Journal / 0 MDPI Journals / 22 papers from journals (References)
Τhe number for papers from Machines journal
is considered insufficient (in reviewer's opinion).

Response 32: New references and some from MDPI Journals have been added.

Author Response File: Author Response.pdf

Reviewer 2 Report

The contribution of the paper is not clear. It is suggested to list the contributions in the introduction section. It requires more in-depth literature review; relevant papers should be considered, e.g. sensor less and sensor based. The advantage of this encoder based system is not discussed in the paper, which is important. There are some well known information/content in the paper (description of some well known devices/components), which should be removed from the paper.  

Author Response

Response to Reviewer 2 Comments

Point 1: The contribution of the paper is not clear. It is suggested to list the contributions in the introduction section. It requires more in-depth literature review; relevant papers should be considered, e.g. sensor less and sensor based. The advantage of this encoder based system is not discussed in the paper, which is important. There are some well known information/content in the paper (description of some well known devices/components), which should be removed from the paper.. 


Response 1: Some reference works have been added that address machine control strategies using the sensorless control strategy. In this work, we chose to use the Indirect Field Oriented Control (IFOC) strategy with a sensor attached to the machine axis because even with parametric variations or uncertainties in the machine model the control still works.

It is known that the use of an encoder makes the project more expensive, however, the bench built and used in the tests has an encoder so that new implementations and control strategies can be validated. The article from which this study originated presents more details of the hardware construction so that undergraduate students can use it as a base reference for their studies and projects.

Still, the authors are interested in a new publication using the same hardware without the use of the encoder. This way, it is also possible to create a comparison between the two implementations developed.

Some of the information presented in this work is known to the scientific and academic groups. However, as this work comes from another one in which the hardware is well roofed, it was decided to present this information.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comment 1
Line 21
demands [1,4]
replace [add a .]
demands [1,4].

Comment 2
Line 67
The authors must format the paper according to the journal's instructions.
The word Processors is out of text limit.

Comment 3
Line 102
Finally, section 7
replace
Finally, Section 7

Comment 4
References
31.
(acessed on 06 June 2021).
33.
(acessed on 28 May 2021).
34.
(acessed on 25 April 2021).
35.
(acessed on 10 May 2021).
36.
(acessed on 08 May 2021).

The word acessed for all above References must be replaced (accessed).
The authors must check for typographical and spelling errors.

Author Response

Response to Reviewer 1 Comments

Point 1:

Line 21
demands [1,4]
replace [add a .]
demands [1,4].

Response 1: The end point has been added to the paragraph.

Point 2:

Line 67
The authors must format the paper according to the journal's instructions.
The word Processors is out of text limit.

Response 2: Text margins have been respected.

Point 3:

Line 102
Finally, section 7
replace
Finally, Section 7

Response 3: The initial letter of the word "section" has been changed to uppercase.

Point 4:

References
31.
(acessed on 06 June 2021).
33.
(acessed on 28 May 2021).
34.
(acessed on 25 April 2021).
35.
(acessed on 10 May 2021).
36.
(acessed on 08 May 2021).

The word acessed for all above References must be replaced (accessed).
The authors must check for typographical and spelling errors.

Response 4: All the words “accessed” have been corrected to “accessed”.

Reviewer 2 Report

I suggest to remove figures 4 to 9 from the paper as they are well known and existing knowledge. There is no point to include these in this paper.

Author Response

Response to Reviewer 2 Comments

Point 1: I suggest to remove figures 4 to 9 from the paper as they are well known and existing knowledge. There is no point to include these in this paper.

Response 1: The figures that previously occupied positions 4, 7 and 9 were removed, because they are figures that are in the datasheet of the FNA41560 module. However, the figures that previously occupied positions 5, 6 and 8 were kept because they present important information about the operation of the developed hardware and are not present in any datasheet. Furthermore, their exclusion makes the text poor in information about the commissioned hardware.