research article cathodic protection of pipeline using...

Research ArticleCathodic Protection of Pipeline UsingDistributed Control System

Gopalakrishnan Jayapalan Ganga Agnihotri and D M Deshpande

Electrical Engineering Department MANIT Bhopal 462051 India

Correspondence should be addressed to Gopalakrishnan Jayapalan jgkrishnanyahoocom

Received 30 January 2014 Revised 24 March 2014 Accepted 7 April 2014 Published 16 June 2014

Academic Editor Flavio Manenti

Copyright copy 2014 Gopalakrishnan Jayapalan et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Distributed control system (DCS) is available in most of the compressor stations of cross-country pipeline systems Programmablelogic controller (PLC) is used in all the intermediate pigging (IP) stationssectional valve (SV) stations to collect the field data andto control the remote actuated valves This paper presents how DCS or PLC can be used for cathodic protection of gas pipelinesVirtual instrumentation (VI) software is used here for simulation and real-time implementation purpose Analog input channelsavailable in DCSPLC can be used to measure pipe to soil potential (PSP) with the help of half-cell and voltage transducer Logicblocks available in DCS can be used as low selector switch to select the lowest PSP Proportional-integral (PI) controller availablein DCSPLC can be used for taking the controlling action PI controller output varies the firing angle of AC phase controller Phasecontroller output is rectified filtered and fed to the pipeline as cathodic protection current Proposed scheme utilizes existinginfrastructure to control pipeline corrosion

1 Introduction

Corrosion is a phenomenon by which metal is etched awaynaturally contributing tomaterial loss Corrosion reduces thelife of metal structures Methane rich natural gas is beingtransported through underground metal pipeline at highpressure Corrosion in pipeline leads to material loss gasleakage and interruption in gas supply Underground metal-lic pipelines are primarily protected by coatings Impressedcurrent cathodic protection is used to protect pipelines fromcoating defects When pipeline is laid underground soil actsas electrolyte in a corrosion cell and corrosion occurs inmetal pipeline primarily due to differential corrosion cellBy impressing current to the pipeline the entire structure ismade to become a cathode of the corrosion cell Impressedcurrent corrosion controller should be dynamic enough toprotect pipelines from ill effects due to variation in coatingdefects soil resistance soil pH temperature and so forthThemain objectives and requirements of cathodic protection(CP) systems are to prevent external corrosion throughoutthe design life of the pipeline by providing sufficient currentto the pipeline to be protected Distributed control system(DCS) is available in most of the compressor stations of

cross-country natural gas pipeline systems Programmablelogic controller (PLC) is used in all the intermediate pigging(IP) stations to collect the field data and to control the remoteactuated valves

Impressed current cathodic protection and details onpipe to soil measurement and half-cell are available in [1]Laboratory set-up for impressed current cathodic protectionis given in [2] Details on PI controllers and their tuning aregiven in [3 4] Module type switching rectifier for maritimeapplication is given in [5 6] Virtual instrumentation (VI)basics and its application for fault diagnostic are givenin [7] Application of virtual instrumentation for cathodicprotection stray currentmonitoring is reported in [8] Virtualinstrumentation for natural gas pipeline corrosion controlis reported in [9] and its autotuning is discussed in [10]This paper deals with how DCSPLC can be utilized for gaspipeline corrosion monitoring and control

2 Experimental Procedure

Schematic diagram of the proposed pipeline cathodicprotection through DCS is shown in Figure 1 PortableCopper-Copper Sulphate (Cu CuSo

4) half-cell reference

Hindawi Publishing CorporationChinese Journal of EngineeringVolume 2014 Article ID 681908 7 pageshttpdxdoiorg1011552014681908

2 Chinese Journal of Engineering

Analog input card

AI

Distributedcontroller

Operatorstation

Analog output card

AO

Phase control module

Step down rectifier and filter module

Anode bed

Gas

pip

elin

e

Half-cell

+minus

50Hz power

VI converter

230V AC1Oslash

Figure 1 Schematic diagram of cathodic protection through distributed control system

electrode is used to measure the pipe to soil potential (PSP)of the underground metallic gas pipeline For simulation andimplementation [2] purposes virtual instrumentation (VI)software (which contains most of the features available in thecommercially available DCS systems) is used In normal casePSP will be in the range of minus04 to minus15 volts PSP signal isfed to the analog input card Desired set point (normally minus12volts) is fed through operator station Proportional-integral(PI) controller is used to take corrective action Output of thecontroller is used to vary the single phase AC phase controllertriggering angle Varied AC is rectified filtered and fed to thepipeline as counter corrosion current (impressed current)

Operator screen is designed in such a way that user canmonitor and control PSP from a single screen Designedoperator screen is shown in Figure 2 Desired proportionalgain and integral time are set through operator screenAutomanual action can be selected In manual mode setpoint (SP) goes as manipulated variable (MV) that is outputwhereas in auto mode PI controller takes corrective action

Program written to control the corrosion in pipeline isshown in Figure 3 Conventionally for impressed currentcontrol purpose 24V20A or 50V50A transformer rectifierunit is used based on the line size and line length In theproposed controller instead of using single unit it is splitinto four units of 24V5A Normally one unit will cater theimpressed current requirement of the pipeline and additionalpower modules of 24V5A will be added (switched on)based on the load (pipeline coating damageline exposure)requirement To avoid abrupt change in the output when thetwo power modules are added in parallel gradual loading ofadditional module is done by introducing slope Flip flop isused to switch on the additional power module For instancein the program additionalmodule is selected once the outputcurrent crosses 8A and additional module is disconnectedonce the output current is reduced to 5A

PI (proportional-integral) control is the most commoncontrol used in industry PI controller consists of two basiccoefficients proportional gain (P) and integral constant (I)which are varied to get optimal response The basic ideabehind a PI controller is to read a signal and compare itwith the set point and then compute the desired actuator

output by calculating proportional and integral responses andsumming those two components to compute the output asgiven in

CO = 119870119901119890 + 119870

119894int 119890 119889119905 (1)

where CO is the controller output e Error (119890) = Set point minusProcess Value 119870

119901is the proportional gain and 119870

119894is the

integral constantThe proportional component [4] depends only on the

difference between the set point and the process variableThis difference is referred to as the ldquoerrorrdquo term (e) Theproportional gain determines the ratio of output responseto the error signal For instance if the error term has amagnitude of 10 a proportional gain of 5 would producea proportional response of 50 In general increasing theproportional gain will increase the speed of the controlsystem response However if the proportional gain is toolarge the process variable will begin to oscillate The integralcomponent sums the error term over time The result is thateven a small error term will cause the integral componentto increase slowly Steady-state error is the final differencebetween the process variable and the set point The integralresponse will continually increase over time unless the erroris zero so the effect is to drive the steady-state error to zero

The process of setting the optimal gains for 119875 and 119868 to getan ideal response from a control system is called tuning Oncethe proportional gain is increased then the system becomesfaster but caremust be taken not tomake the systemunstableOnce 119875 has been set to obtain a desired fast response theintegral term 119868 is increased to stop the oscillations

A sensor (half-cell) is used to measure the processvariable (PSP) and it provides feedback to the control systemThe set point is the desired or the command value for theprocess variable The difference between the process variable(PSP) and the set point is used by the control system todetermine the desired actuator output to drive the system

Controllermodule output is fed to the phase controlmod-ule (output AC voltage varies based on controller output) Forzero crossing detection purpose synchronous voltage has tobe given to the phase controller AC phase controller output

Chinese Journal of Engineering 3

Figure 2 Operator screen of corrosion controller

Voltage

TF

DBLDBLinfin

DBLDBL

infin

T

intd

dt

DAQ assistant Data

T F

DC

DC

DAQ assistant 2 Data

Ch0 amp 1 AO0Ch1 2 amp 3 AO1

Ch0 4 amp 5 PSPCh1 4 amp 5 voltageCh2 4 amp 5 current

iDBL

DBL

EXT

TF

TF

F

DBL

DBL

DBLDBL

DBL

X1Result

X1Result

X1Result

TF

infin

NI 9263

NI 9219

TF

SM2

Switching module

Simulate signal

Simulatesignal 2

TF

TF

+

divide

times

times

1000

123

123

Sampling time dt (s)U32

OP1 OP2 voltage

Module II on

Switching on

Switch on II Req

OP1 OP2 current

MV

PVPID gains

PV set point

05

0510

10

Current

005

100

0

99

1not

^

^

^minus1

Slope count

OP current

100

008

OP voltage

TF

TF

TFtimes

times

TF

06

15

0

or

or

or

or

or

TF

TF

TF

lele

Automan

PI corrosion controller with switching block diagram

123

Kp 05Ti 018Td 001

Output high Output low

SP

f(xy)

Formula 3

FormulaFormula 2

F

F

F

PIDG

f(xy)

f(xy)

DBL

123

DBL

123

DBL

DBLDBL

1

T

T

T

⩽

⩾

⩾

⩽

⩽

⩾

Figure 3 Corrosion controller program

is fed to the step down transformer Step down transformeroutput is rectified filtered and then fed to the pipelinePurpose of the step down transformer is to reduce the voltageto nonobjectionable level and to meet the load side currentrequirement Output voltage of AC phase control circuit isgoverned by

119881

119889prop=

1

2120587

int

120587

120572

119881max sin120596119905119889 (120596119905) =119881max2120587

(1 + cos prop) (2)

whereprop is the phase angleTable 1 shows the result obtained between the DC output

voltage of the PI controller and the corresponding variable


Table 1 Control voltage versus output AC voltage

Control voltage DC Output voltage AC605 10556 265507 456455 686406 94342 1266299 148257 1687209 1882157 203107 216064 223

NI 9219(AI)PSP

System loaded with LabVIEW

2012

NI 9263(AO)

cDAQ NI 9178

Gas

pip

e lin

e

Rectifiermodule

Rectifiermodule

Anode bed

+minus

V

I

Vo1

Vo2

Ch0 4 +

Ch0 5 ndash

Ch1 4 +Ch2 5 ndash

Ch2 4 +Ch2 5 ndash

Ch0 0 +

Ch0 1 minus

Ch1 0 +

Ch1 1 minus

Figure 4 Experimental set-up

ACobtainedHere single phase 230VAC50Hz power supplyis used Scaling and mapping may be done to match the DCSPI controller output to control the single phase AC controllereither through hardware or software

Experimental set-up is shown in Figure 4 Three-analoginput channels and two-analog output channels are usedfor experiment purpose In the figure dotted line showsthe additional power supply module which will becomeonline when first module is unable to cater the load demandRectifiermodule consists of phase controlmodule step downtransformer rectifier and filters

ACphase controller rating selection is purely based on thepipeline size pipeline length type of coating used and cur-rent density used for protection Total current requirement toprotect the pipeline is calculated as shown in (3) Surface areaof the pipeline is calculated as shown in (4)

119868

119905=

119878

119886119862

119889119878

119891

10

6amperes (3)

where 119878119886is the total surface area of the gas pipeline in square

meters 119862119889is the current density (125 120583AM2) for marshy

area and 119878119891is the safety factor (13)

119878

119886= 120587119863119871M2 (4)


meters 119863 is the diameter of the pipeline in meters and 119871 isthe length of the pipeline in meters

3 Results and Discussions

Designed controller is checked with different PSP set pointsand it is controlling perfectly Output response obtainedthrough the designed PI controller is shown in Figure 5(a)Set point has been changed from minus12 to minus15 and then tominus17 volts PSP is maintained at set level Controller is givingdesired result that is process value is tracking the set pointHere PSP is the process value

Load variation (perturbation introduced into the sys-tem) has been created by varying the electrolyte resistanceResponse of the controller is shown in Figure 5(b) Initiallyelectrolyte conductivity is varied by diluting with waterand controller performance is observed Controller broughtthe process value (PSP) towards the set point Variation inelectrolyte pH affects corrosion process and acidic natureaccelerates corrosion processThen electrolyte pH is varied byadding sodiumchloride to it and then controller performanceis observed In both cases the controller is taking correctiveaction and brining process value towards set point

As shown in Table 2 given below protection currentrequirement drastically varies based on the coating resis-tance When the coating is in good condition currentrequirement will be very low it may be one or two amperesfor 10 miles of 3610158401015840 diameter pipeline whereas when thecoating is damaged or pipe line exposure occurred in oneor more locations more protection current will be required(till the time coating is repaired) say 15 amperes In practicalapplications 50V 50A rated transformer is used to provideprotection current Normally this transformer may be sup-plying only one or two amperes to the pipeline when the pipecoating is in good condition hence idle loss will be more init

Instead of designing 50 volts 50A as a single unit fiveunits of 50 volts 10 A can be designed and operated in parallelNormally only one unit (rated 50V 10A) will be online tocater the current demand another powermodule of 50V 10Awill be added once the firstmodule reaches 80of its capacity(say 8A) As written in the program (Figure 3) additionalmodule is added once the output current crosses 8A As


minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 223

(sec)

(V)

PSP minus130Set point minus130

(a)

minus11

minus12

minus13

0 79

(sec)

(V)


(b)

Figure 5 (a) Response of the designed PI controller to set point change (b) Response of the PI controller to load variation

Table 2 Range of current required for protection of 10 miles 0f 3610158401015840diameter pipe [1]

Effective coating resistance inohms for one average squarefoot

Current required in amperes

Bare Pipe 50010000 149125000 596450000 1491500000 014911000000 00298Perfect coating 0000058Bare pipe assumed to require a minimum of 1mAft2

shown in the graph (Figure 6(a)) additional module (OP2)is gradually loaded and existing module (OP1) is graduallyunloaded When load demand is reduced to less than 50of the first module rating (say 5A) then added module isgradually unloaded as shown

If first power module failed then second module willcome online automatically For instance say first powersupply module failed and controller output voltage to firstpower module reached 15 V (this value can be set throughprogram) then second power module will come onlinegradually as shown in Figure 6(b)

As shown in Figure 7(a) if the additional module istaken online immediately it creates disturbance in PSPby impressing more current For instance at 32 secondsadditional module is added immediately (due to total currentdemand which is increased to more than 8 amperes) processvalue (PSP) is disturbed from minus17 volts to minus21 volts forbrief period Such disturbance is avoided by gradually loadingthe additional power module as shown in Figure 7(b) To

achieve gradual loading and unloading upward and down-ward counter is introduced in the program (in Figure 3)and counter value is multiplied by controller output (foradditional module)

Successful implementation of cathodic protection usingDCShelps us to centralize monitoring and control of pipelinecorrosion Different channel has to be allotted for differentpipeline and anode bed PSP historical trend can be recordedPSP variation can be easily identified With DCS operationswitchover from auto to manual mode and manual to automode is easy Manual mode is used during start-up Alarmrecordwill be availablewith time stampAutotuning feature isavailable inDCSPLC It is amodular concept Fault diagnosis[7] is easy Rate alarm can be used to find the damagein the pipeline coating Simulation can be done withoutaffecting the process In the designed software based cathodicprotection controller and additiondeletion of logic modi-fications are easier Signal repetition is easier with highestpossible accuracy For data transmission implementation ofMODBUS Profibus industrial Ethernet communication andso forth is easier with DCSPLC

Stray current monitoring [8] is possible with virtualinstrumentation Impressed current cathodic protection [1]is commonly used in pipeline industries for corrosion pro-tection Corrosion protection can be implemented usingsimple PI controller [9] Simple controller will not providea lot of features available in DCS such as graphic operatorstation trending alarm and data transmission Autotuningof PI controller [10] helps in selecting optimum controlparameters

4 Conclusions

Design and developmentwork ofPI corrosion controller withswitching module is undertaken for underground pipeline in


180

160

140

120

100

80

60

40

20

00

2040

(sec)

VV

middotA

OP1 101OP2 000

Current 408

(a)

35

30

25

20

15

10

05

0077

0

(sec)003

VV

middotA

OP1 050OP2 000

Voltage 003

(b)

Figure 6 (a) Output module switching on output current condition (b) Output module switching on output voltage condition

0 84

(sec)

Volta

ge

minus12

minus14

minus16

minus18

minus10

minus08

minus06

minus20

minus22


(a)

minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 213

(sec)

minus10

minus09

minus08

minus07

minus06

minus05

Volta

ge


(b)

Figure 7 (a) Impact of immediate loading of additional module (b) Gradual loading of additional module

distributed control system It prevents the pipeline corrosionby precisely controlling the pipe to soil potential (PSP) at thedesired level Self-tuning feature available inDCS can be usedfor optimum selection of PI controller parameters Insteadof using single high current rated transformer rectifier unitmultiple modules connected in parallel configuration can beused Output module switching is discussed in detail Thesame application can be extended to any of the other steelstructures like underground tank and so forth

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] A W Peabody Control of Pipeline Corrosion NACE HoustonTex USA 2nd edition 2001

[2] S M Bashi N F Mailah and M A M Radzi ldquoCathodicprotection systemrdquo in Proceedings of the National Power andEnergy Conference (PECon rsquo03) pp 366ndash370 IEEE BengiMalaysia December 2003

[3] A OrsquoDwyer Handbook of PI and PID Controller Tuning RulesImperial College Press 3rd edition 2009

[4] Y Li K H Ang and G C Y Chong ldquoPatents software andhardware for PID control an overview and analysis of thecurrent artrdquo IEEE Control Systems Magazine vol 26 no 1 pp42ndash54 2006


[5] M N Cirstea M Giamusi andMMcCormick ldquoModern ASICcontroller for a 6-pulse rectifierrdquo in Proceedings of the 10thAnnual IEEE International ASIC Conference and Exhibit pp335ndash338 September 1997

[6] I-D Kim and E-C Nho ldquoModule-type switching rectifierfor cathodic protection of underground and maritime metallicstructuresrdquo IEEE Transactions on Industrial Electronics vol 52no 1 pp 181ndash189 2005

[7] L Shijun Z Minghu L Youfeng and Y Xiaojuan ldquoDesignon the fault diagnostic system based on virtual instrumenttechniquerdquo in Proceedings of the 2nd International Workshop onKnowledge Discovery and Data Mining (WKKD rsquo09) pp 304ndash307 January 2009

[8] Z-G Chen C-K Qin Y-J Zhang and X-C Yang ldquoAppli-cation of a stray current monitoring system base upon virtualinstrumentrdquo in Proceedings of the IEEE International Conferenceon Automation and Logistics (ICAL rsquo10) pp 341ndash344 HongKong and Macau China August 2010

[9] J Gopalakrishnan G Agnihotri and D M DeshpandeldquoVirtual instrumentation corrosion controller for natural gaspipelinesrdquo Journal of the Institution of Engineers B vol 93 no4 pp 259ndash265 2012

[10] J Gopalakrishnan and G Agnihotri D M Deshpande ldquoAutotuned corrosion controller for natural gas pipelinesrdquo in Proceed-ings of theNational Conference onElectronic Technologies (NCETrsquo12) pp 327ndash330 Goa India April 2012

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



Analog input card

AI

Distributedcontroller

Operatorstation

Analog output card

AO

Phase control module

Step down rectifier and filter module

Anode bed

Gas

pip

elin

e

Half-cell

+minus

50Hz power

VI converter

230V AC1Oslash

Figure 1 Schematic diagram of cathodic protection through distributed control system

electrode is used to measure the pipe to soil potential (PSP)of the underground metallic gas pipeline For simulation andimplementation [2] purposes virtual instrumentation (VI)software (which contains most of the features available in thecommercially available DCS systems) is used In normal casePSP will be in the range of minus04 to minus15 volts PSP signal isfed to the analog input card Desired set point (normally minus12volts) is fed through operator station Proportional-integral(PI) controller is used to take corrective action Output of thecontroller is used to vary the single phase AC phase controllertriggering angle Varied AC is rectified filtered and fed to thepipeline as counter corrosion current (impressed current)

Operator screen is designed in such a way that user canmonitor and control PSP from a single screen Designedoperator screen is shown in Figure 2 Desired proportionalgain and integral time are set through operator screenAutomanual action can be selected In manual mode setpoint (SP) goes as manipulated variable (MV) that is outputwhereas in auto mode PI controller takes corrective action

Program written to control the corrosion in pipeline isshown in Figure 3 Conventionally for impressed currentcontrol purpose 24V20A or 50V50A transformer rectifierunit is used based on the line size and line length In theproposed controller instead of using single unit it is splitinto four units of 24V5A Normally one unit will cater theimpressed current requirement of the pipeline and additionalpower modules of 24V5A will be added (switched on)based on the load (pipeline coating damageline exposure)requirement To avoid abrupt change in the output when thetwo power modules are added in parallel gradual loading ofadditional module is done by introducing slope Flip flop isused to switch on the additional power module For instancein the program additionalmodule is selected once the outputcurrent crosses 8A and additional module is disconnectedonce the output current is reduced to 5A

PI (proportional-integral) control is the most commoncontrol used in industry PI controller consists of two basiccoefficients proportional gain (P) and integral constant (I)which are varied to get optimal response The basic ideabehind a PI controller is to read a signal and compare itwith the set point and then compute the desired actuator

output by calculating proportional and integral responses andsumming those two components to compute the output asgiven in

CO = 119870119901119890 + 119870

119894int 119890 119889119905 (1)

where CO is the controller output e Error (119890) = Set point minusProcess Value 119870

119901is the proportional gain and 119870

119894is the

integral constantThe proportional component [4] depends only on the

difference between the set point and the process variableThis difference is referred to as the ldquoerrorrdquo term (e) Theproportional gain determines the ratio of output responseto the error signal For instance if the error term has amagnitude of 10 a proportional gain of 5 would producea proportional response of 50 In general increasing theproportional gain will increase the speed of the controlsystem response However if the proportional gain is toolarge the process variable will begin to oscillate The integralcomponent sums the error term over time The result is thateven a small error term will cause the integral componentto increase slowly Steady-state error is the final differencebetween the process variable and the set point The integralresponse will continually increase over time unless the erroris zero so the effect is to drive the steady-state error to zero

The process of setting the optimal gains for 119875 and 119868 to getan ideal response from a control system is called tuning Oncethe proportional gain is increased then the system becomesfaster but caremust be taken not tomake the systemunstableOnce 119875 has been set to obtain a desired fast response theintegral term 119868 is increased to stop the oscillations

A sensor (half-cell) is used to measure the processvariable (PSP) and it provides feedback to the control systemThe set point is the desired or the command value for theprocess variable The difference between the process variable(PSP) and the set point is used by the control system todetermine the desired actuator output to drive the system

Controllermodule output is fed to the phase controlmod-ule (output AC voltage varies based on controller output) Forzero crossing detection purpose synchronous voltage has tobe given to the phase controller AC phase controller output



Voltage

TF

DBLDBLinfin

DBLDBL

infin

T

intd

dt

DAQ assistant Data

T F

DC

DC




iDBL

DBL

EXT

TF

TF

F

DBL

DBL

DBLDBL

DBL

X1Result

X1Result

X1Result

TF

infin

NI 9263

NI 9219

TF

SM2

Switching module

Simulate signal

Simulatesignal 2

TF

TF

+

divide

times

times

1000

123

123


OP1 OP2 voltage

Module II on

Switching on

Switch on II Req

OP1 OP2 current

MV

PVPID gains

PV set point

05

0510

10

Current

005

100

0

99

1not

^

^

^minus1

Slope count

OP current

100

008

OP voltage

TF

TF

TFtimes

times

TF

06

15

0

or

or

or

or

or

TF

TF

TF

lele

Automan


123

Kp 05Ti 018Td 001


SP

f(xy)

Formula 3

FormulaFormula 2

F

F

F

PIDG

f(xy)

f(xy)

DBL

123

DBL

123

DBL

DBLDBL

1

T

T

T

⩽

⩾

⩾

⩽

⩽

⩾



119881

119889prop=

1

2120587

int

120587

120572

119881max sin120596119905119889 (120596119905) =119881max2120587

(1 + cos prop) (2)






NI 9219(AI)PSP


2012

NI 9263(AO)

cDAQ NI 9178

Gas

pip

e lin

e

Rectifiermodule

Rectifiermodule

Anode bed

+minus

V

I

Vo1

Vo2

Ch0 4 +

Ch0 5 ndash

Ch1 4 +Ch2 5 ndash

Ch2 4 +Ch2 5 ndash

Ch0 0 +

Ch0 1 minus

Ch1 0 +

Ch1 1 minus





119868

119905=

119878

119886119862

119889119878

119891

10

6amperes (3)




119878

119886= 120587119863119871M2 (4)









minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 223

(sec)

(V)


(a)

minus11

minus12

minus13

0 79

(sec)

(V)


(b)












4 Conclusions



180

160

140

120

100

80

60

40

20

00

2040

(sec)

VV

middotA

OP1 101OP2 000

Current 408

(a)

35

30

25

20

15

10

05

0077

0

(sec)003

VV

middotA

OP1 050OP2 000

Voltage 003

(b)


0 84

(sec)

Volta

ge

minus12

minus14

minus16

minus18

minus10

minus08

minus06

minus20

minus22


(a)

minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 213

(sec)

minus10

minus09

minus08

minus07

minus06

minus05

Volta

ge


(b)





References














RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











Voltage

TF

DBLDBLinfin

DBLDBL

infin

T

intd

dt

DAQ assistant Data

T F

DC

DC




iDBL

DBL

EXT

TF

TF

F

DBL

DBL

DBLDBL

DBL

X1Result

X1Result

X1Result

TF

infin

NI 9263

NI 9219

TF

SM2

Switching module

Simulate signal

Simulatesignal 2

TF

TF

+

divide

times

times

1000

123

123


OP1 OP2 voltage

Module II on

Switching on

Switch on II Req

OP1 OP2 current

MV

PVPID gains

PV set point

05

0510

10

Current

005

100

0

99

1not

^

^

^minus1

Slope count

OP current

100

008

OP voltage

TF

TF

TFtimes

times

TF

06

15

0

or

or

or

or

or

TF

TF

TF

lele

Automan


123

Kp 05Ti 018Td 001


SP

f(xy)

Formula 3

FormulaFormula 2

F

F

F

PIDG

f(xy)

f(xy)

DBL

123

DBL

123

DBL

DBLDBL

1

T

T

T

⩽

⩾

⩾

⩽

⩽

⩾



119881

119889prop=

1

2120587

int

120587

120572

119881max sin120596119905119889 (120596119905) =119881max2120587

(1 + cos prop) (2)






NI 9219(AI)PSP


2012

NI 9263(AO)

cDAQ NI 9178

Gas

pip

e lin

e

Rectifiermodule

Rectifiermodule

Anode bed

+minus

V

I

Vo1

Vo2

Ch0 4 +

Ch0 5 ndash

Ch1 4 +Ch2 5 ndash

Ch2 4 +Ch2 5 ndash

Ch0 0 +

Ch0 1 minus

Ch1 0 +

Ch1 1 minus





119868

119905=

119878

119886119862

119889119878

119891

10

6amperes (3)




119878

119886= 120587119863119871M2 (4)









minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 223

(sec)

(V)


(a)

minus11

minus12

minus13

0 79

(sec)

(V)


(b)












4 Conclusions



180

160

140

120

100

80

60

40

20

00

2040

(sec)

VV

middotA

OP1 101OP2 000

Current 408

(a)

35

30

25

20

15

10

05

0077

0

(sec)003

VV

middotA

OP1 050OP2 000

Voltage 003

(b)


0 84

(sec)

Volta

ge

minus12

minus14

minus16

minus18

minus10

minus08

minus06

minus20

minus22


(a)

minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 213

(sec)

minus10

minus09

minus08

minus07

minus06

minus05

Volta

ge


(b)





References














RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












NI 9219(AI)PSP


2012

NI 9263(AO)

cDAQ NI 9178

Gas

pip

e lin

e

Rectifiermodule

Rectifiermodule

Anode bed

+minus

V

I

Vo1

Vo2

Ch0 4 +

Ch0 5 ndash

Ch1 4 +Ch2 5 ndash

Ch2 4 +Ch2 5 ndash

Ch0 0 +

Ch0 1 minus

Ch1 0 +

Ch1 1 minus





119868

119905=

119878

119886119862

119889119878

119891

10

6amperes (3)




119878

119886= 120587119863119871M2 (4)









minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 223

(sec)

(V)


(a)

minus11

minus12

minus13

0 79

(sec)

(V)


(b)












4 Conclusions



180

160

140

120

100

80

60

40

20

00

2040

(sec)

VV

middotA

OP1 101OP2 000

Current 408

(a)

35

30

25

20

15

10

05

0077

0

(sec)003

VV

middotA

OP1 050OP2 000

Voltage 003

(b)


0 84

(sec)

Volta

ge

minus12

minus14

minus16

minus18

minus10

minus08

minus06

minus20

minus22


(a)

minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 213

(sec)

minus10

minus09

minus08

minus07

minus06

minus05

Volta

ge


(b)





References














RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 223

(sec)

(V)


(a)

minus11

minus12

minus13

0 79

(sec)

(V)


(b)












4 Conclusions



180

160

140

120

100

80

60

40

20

00

2040

(sec)

VV

middotA

OP1 101OP2 000

Current 408

(a)

35

30

25

20

15

10

05

0077

0

(sec)003

VV

middotA

OP1 050OP2 000

Voltage 003

(b)


0 84

(sec)

Volta

ge

minus12

minus14

minus16

minus18

minus10

minus08

minus06

minus20

minus22


(a)

minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 213

(sec)

minus10

minus09

minus08

minus07

minus06

minus05

Volta

ge


(b)





References














RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










180

160

140

120

100

80

60

40

20

00

2040

(sec)

VV

middotA

OP1 101OP2 000

Current 408

(a)

35

30

25

20

15

10

05

0077

0

(sec)003

VV

middotA

OP1 050OP2 000

Voltage 003

(b)


0 84

(sec)

Volta

ge

minus12

minus14

minus16

minus18

minus10

minus08

minus06

minus20

minus22


(a)

minus11

minus12

minus13

minus14

minus15

minus16

minus17

minus18

0 213

(sec)

minus10

minus09

minus08

minus07

minus06

minus05

Volta

ge


(b)





References














RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









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