A Single-Stage SPV-Fed Reduced Switching Inverter-Based ...

Research ArticleA Single-Stage SPV-Fed Reduced Switching Inverter-BasedSensorless Speed Control of IM for Water Pumping Applications

Ankireddy Narendra 1 Naik N Venkataramana 1 Anup Kumar Panda 1

Nishit Tiwary 1 and Amit Kumar 2

1Department of Electrical Engineering National Institute of Technology Rourkela Odisha India2Department of Electrical and Instrumentation Engineering apar Institute of Engineering and TechnologyPatiala Punjab India

Correspondence should be addressed to Amit Kumar amitkumar2thaparedu

Received 6 February 2022 Revised 20 April 2022 Accepted 6 May 2022 Published 25 June 2022

Academic Editor Gayadhar Panda

Copyright copy 2022 Ankireddy Narendra et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

is article elaborates on a reduced switch count-based inverter for a single-stage solar photovoltaic (SPV) fed induction motor(IM) with sensorless speed control for water pumping applications e traditional SPV-fed IM for water pumping applicationsrequires a six-switch voltage source inverter (SSVSI) for transforming the DC power from the SPV system into AC powerHowever the same performance is achieved using a four-switch voltage source inverter (FSVSI) Here the entire system requiresless number of switches and hence reduces switching losses and cost as compared to the traditional solar water pumping systemMoreover the sensorless speed control is implemented using a speed estimator to reduce the overall cost further and enhancereliability e reference voltage (Vdcr) is achieved using an adapted incremental conductance (AINC) and the control of IM isperformed using direct vector control (DVC) e control signals for the proposed system are generated using DSPACE DS-1104for real-time implementation e proposed SPV-fed FSVSI-based 1-HP IM operation is performed at different irradiation levelsin the MATLAB-Simulink environment and validated experimentally

1 Introduction

e increase in electrical power utilization is due to urbani-zation and globalization Hence the conventional power gen-eration methods cannot meet the exponential growth ofelectrical power demand due to the limited availability of coalcrude oil and natural gas Moreover conventional electricalpower generation is adversely impacting the environmentHence alternative electrical power generation methods are vitalin meeting the global electrical power demand such as solarwind and tidal ese new alternative electric power genera-tions realized practical Out of all the possible alternative electricpower generations solar power is growing drastically due to itszero fuel cost and low maintenance [1] e solar photovoltaic(PV) panels generate the DC power based on solar irradiationlevels So the higher the solar irradiation provides the higherthe electric power generation [2]

esignificant cost associatedwith solarpowergenerationis PV panels made up of semiconductor materials Due toadvancements in semiconductormaterials the cost of the SPVpanels is reducing day by day But the SPV panel suffers fromlow efficiency and this problem is overcome with the help ofthe maximum power point tracking (MPPT) algorithm [3]Moreover the SPV panel output voltage and current ratingsare increased using series and parallel connections of panelsrespectively

As solar energy is available free of cost and pollution-freewaterpumping isoneof themajor applicationsesolarwaterpumps are used for drinking water irrigation and cultivationpurposes ese water pumps accelerate the cultivation inemerging countries isolated from the grid [4] Moreover thesolar water pumps are also noise-free and economical com-pared todieselpumpsHowever solarpower isavailableduringsunny times only and tomake the continuous operation of the

HindawiInternational Transactions on Electrical Energy SystemsVolume 2022 Article ID 3805791 12 pageshttpsdoiorg10115520223805791

solar pump batteries [5] are used But the batteries increase theoverall cost and require regularmaintenanceebatteries canbe avoided in the solar water pumping systems using eitherused directly during the sunny period or stored the water in astorage tank [6] and reuse water as per convenience

e AC solar water pumping systems are classified astwo-stage and single-stage systems In a two-stage systemDC-DC and DC-AC converters are connected cascade Dueto the presence of a DC-DC converter two-stage systems arecostlier and more complex So to avoid these problems asingle-stage system is used for the direct conversion of SPVpower to a water pumping system using an inverter Tofurther reduce the cost switching losses and complexity ofthe solar water pumping system the proposed FSVSI is usedrather than the conventional SSVSI However the constantDC-link voltage is maintained for better dynamic perfor-mance using a voltage controller

Moreover at variable solar irradiation the SPV outputcurrents are also varied accordingly to maintain constantDC-link voltage Hence the load current also varies as perthe SPV output current Here a reduced switch count-basedinverter achieves the control of the single-stage SPV-fedsensorless operation of IM for water pumping applications

In AC solar water pumping systems inductionmotors areutilized due to low cost high reliability and low operationalmaintenance Now the speed control of IM is the primaryconcern for solar water pumping applications However theIM speed control is performed using either scalar (Vf) [7ndash9]or vector control In scalar control the IM drive speed iscontrolled with decreasing input voltage and frequency belowthe rated values to maintain a constant flux and torqueHowever the scalar control can control the speed of the IMup to baserated speed only and suffers from poor dynamicsespecially at lower speed range [10] and when reference speedis more than slip speed range control Vector control isgenerally preferred to overcome problems associated with theVf control However the vector control is further classifiedas direct torque control (DTC) [11] and field-oriented control(FOC) e DTC of the IM drive suffers from high currenttorque ripple and is very noisy during low speeds compared tothe FOC [12] Hence the FOC is more reliable for speedcontrol of IM than DTC [13] e basic concept of FOC is totransform the IM equivalent to a separately excited DCmotorwith the help of appropriate coordinate transformationsHence the control of IM flux and torques is done inde-pendently and adequately e FOC is further classified asdirect and indirect vector control [14 15]

e organization of the paper is as follows Section 2provides complete modeling of the proposed inverter-basedsolar water pumping system Section 3 depicts the speedcontrol of IM using the direct vector control (DVC) methodSections 4 and 5 describe simulationhardware results andconclusions respectively

2 SPV-Fed IM with Proposed FSVSI for WaterPumping Applications

e schematic view of solar PV-fed proposed FSVSI basedDVC of IM for water pumping applications is shown in

Figure 1 Generally the required output voltage and currentsfor the induction motor are generated using a series andparallel combination of SPV panels Here the solar simu-lator is used to meet the required power demand of the IMand the specifications are given in the Appendix in detaile proposed four-switch three-phase voltage source in-verter can provide the AC supply to an inductionmotor for awater pump load application

e purpose of the proposed inverter configuration usedhere has reduced the number of switching devices sizeoverall cost and switching losses In addition direct vectorcontrol (DVC) is used for IM speed control Also themodeling and design parameters of each part of the wholeconfiguration are disclosed in the following sections

21 PV Modelling e solar PV system is a series andparallel combination of PV cells as per the required outputvoltage and current ratings Hence the single diode-basedPV cell is represented using a current source with internalresistance and the output current produced by PV cell isgiven as follows [16]

Io Ip minus Is eVp+RsIoUta( 1113857

minus 11113874 1113875 minusVp + RseIo

Rs

(1)

where Iops Vp Rsse Ut and a are outputPVsaturationcurrent PV output voltage shuntseries resistance terminalvoltage and ideality factor respectively

However the DC-link capacitance value depends uponthe DC-link voltage motor phase voltage and current asgiven follows

C1 C2 12sVIt

ΔVd

(2)

where C12 s V I t and ΔVd are DC-link capacitance safetymargin IM phase per voltage current time to attain theminimumDC voltage and the difference between minimumand reference DC-link voltage respectively

22 Adaptive Incremental Conductance Algorithm Anadaptive incremental conductance algorithm (AINC) sensesSPV output voltage and current to determine the appro-priate reference dc-link voltage [17 18] based on the con-ductance value

e PV output power is expressed as

Pp VpIp

for attaining maximum powerzPp

zVp

Ip + Vp

zIp

zVp

0

zIp

zVp

minusIp

Vp

(3)

erefore for maximum power extraction from PV isobtained when the change in conductance is equal to theconductance at that point Here in a single-stage systemthe adaptive incremental conductance updates the PV

2 International Transactions on Electrical Energy Systems

output voltage such way to achieve maximum power estep-by-step procedure can be understood with the help ofP-V characteristics of the PV system as shown in Figure 2the transition of points on the P-V curve are consideredand the corresponding change in PV voltage is given inTable 1

e final updated SPV output voltage from the adaptiveincremental conductance algorithm as shown in Figure 3 isan optimal voltage value to retrieve the maximum powerutilization of SPV panels Hence it is considered to referDC-link voltage for voltage regulation as detailed infor-mation in reference speed generation

23 Space Vector Modulation for FSVSI From the proposedFSVSI as shown in Figure 1 the DC-link voltage (Vp) is oneof the significant parameters in the operation of the pro-posed inverter-fed IM and is calculated as [19]

Vp

2

radic

3

radic Vll (4)

where Vll is line-line voltage In the proposed inverter thecomplementary pairs of switches S1S3 and S2S4 can producethe switching pulsesstates for each leg of Qb and Qc re-spectively en the corresponding pole voltages of eachphase in terms of switching pulses are given [20ndash22]

Vr0 Vd1

3minusQb minus Qc( 1113857 +

Vd2

32 minus Qb minus Qc( 1113857

Vy0 Vd1

32Qb minus Qc( 1113857 +

Vd2

32Qb minus Qc minus 1( 1113857

Vb0 Vd1

32Qc minus Qb( 1113857 +

Vd2

32Qc minus Qb minus 1( 1113857

(5)

where Vr0y0b0 and Vd12 are phases to neutral the inductionmotor and DC-link capacitor voltages respectively e DCcapacitorsrsquo voltages are corrupted when there is a flow ofunbalanced current through the capacitors However thevoltage unbalances in DC capacitors tend towards theshutting down of the FSVSI erefore Vd12 has to bebalanced for the reliable operation of the proposed con-verter So the capacitorrsquos voltage balance is achieved usingcertain switching states without the requirement of anyexternal controller [22 23] In FSVSI the unbalance ofvoltages occurs during the switching states of 00 and 11When Vd1 gtVd2 the duration of 11 has to increase Due toan increase in the duration of 11 the discharge time ofcapacitor C1 increases Similarly if Vd2 gtVd1 then theduration of switching state 00 has to increase and then the

IMPum

p

ir

DVC

Pulses

Speed Estimator

Ip

Vp

Vp

Ip

PV

Vd2

Vd1

C2

C1

S3 S4

S2S1

Vd

Vq

idiq

Reference SpeedGeneration

iy

ib

ref

mse

Figure 1 Schematic view of solar PV-fed proposed FSVSI-based DVC of IM for water pumping applications

a4

a3

a2a1

P p (W)

Vp (V)

Figure 2 P-V characteristics of solar panel

Table 1 Variation of PV voltage from P-V characteristics

Movement of pointon P-V

Variation of PV powerand voltage

Updation of PVvoltage

a1 to a2 Ppuarr Vpuarr Vp Vp + ΔVp

a2 to a3 Ppuarr Vpuarr Vp Vp + ΔVp

a3 to a4 Ppdarr Vpuarr Vp Vp + ΔVp

a4 to a3 Ppuarr Vpdarr Vp Vp minus ΔVp

a3 to a2 Ppdarr Vpdarr Vp Vp minus ΔVp

International Transactions on Electrical Energy Systems 3

C2 discharge time is increased Finally it suppresses thevoltage offset with the help of a combination of theseswitching states over a switching period Here the switchingimplementation is performed with the use of the spacevector pulse width modulation (SVM) technique and isdisclosed as follows

e two-level four-switch three-phase inverter consistsof four switching states and is distributed with 90deg dis-placement as shown in Figure 4 and the corresponding polevoltages for each switching state are tableted as shown inTable 2

e three-phase stator voltage equations of the IM havetransformed into αβ-transformation for SVM imple-mentation as follows

Vαβ AVabc (6)

where

A 23

1 minus12

minus12

03

radic

2minus

3

radic

2

⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

(7)

e active vectors v1 v2v3 and v4 are operating for aperiod of t1 t2 t3 and t4 respectively e reference vectorwith a magnitude of vr is rotating synchronously in eachsector According to the volt-sec balance equations [24]

vrts v1t1 + v2t2 + v3t3 + v4t4 (8)

where ts is the total sampling period

ts t1 + t2 + t3 + t4 (9)

However the active vector values are related as v1 minusv3and v2 minusv4 Now the volt-sec balance equation is furthersimplified from equation (12) as

start

Sense Vp (k) Ip (k)

Is Vp (k)- Is I

p (k)minusI

p (kminus1)=0

Is (Ip (k)-Ip (k-1))gt0

Vp=V

p-V

pVp=V

p+V

p

Update Vp

Vp=V

p+V

p

Ip (k)Ip (k) minus Ip (k minus 1)Vp (k) minus Vp (k minus 1) Vp (k)

Vp (k-1)gt0

no

yes

no no no

no yes

yes

yes

minus=Ip (k)Ip (k) minus Ip (k minus 1)

Vp (k) minus Vp (k minus 1) Vp (k)minusgt

Figure 3 AINC algorithm

v1

v2

vr

v4

SectorIII

SectorIISe

ctor

IV

SectorI

v3

Figure 4 Voltage vectors in αβ-axes

Table 2 Switching table for FVSI

Switchingstates Output voltage

Qb Qc Va0 Vb0 Vc0

0 0 2Vd23 minusVd23 minusVd230 1 (Vd2 minus Vd1)3 (2Vd2 + Vd1)3 (2Vd2 + Vd1)31 0 (Vd2 minus Vd1)3 (2Vd2 + Vd1)3 (2Vd2 minus Vd1)31 1 minus2d13 Vd13 Vd13

4 International Transactions on Electrical Energy Systems

vrts v1t13 + v2t24 (10)

where t13 t1 minus t3 and t24 t2 minus t4e active vectors v1 and v2are applied for a period of t13 and t14 respectively Howeverthe active time intervals are calculated using the followingexpressions

t13 minus32

vrα +3

radicvrβ1113872 1113873

2ts

Vd

t24 32

vrα minus13

radic vrβ1113888 11138892ts

Vd

(11)

Finally the position of reference vector magnitude andphase angle can be found from the αβ-transformation of thereferencemodulating wave e reference voltage in termsof αβ-components at each possible state is given in Table 3[21]

3 Speed Control Scheme for IM

e speed control of IM is based on reference and estimatedspeed Here the reference and estimated speed of the motorare varied as per the solar irradiation e speed estimationsare disclosed as follows

31 Reference Speed Generation e reference speed of theinduction motor consists of two terms speed term based onpump load (ω1) and speed term based on DC-link voltage(ω2) [25] as shown in Figure 5 However the pump load ofeither centrifugal or linear load model can be consideredHere a centrifugal pump is assessed and the load torque isproportional to the square of the speed and is expressed as

T mω21 (12)

where T m and ω1 are electromagnetic torque pumpconstant and the IM speed corresponding pump loadrespectively

However the power generated from the SPV system isbalanced with the electromagnetic power as follows

ηPp Tω1 (13)

where Pp and η are the SPV power and efficiency forconverting SPV power tomechanical power Now substituteequations (12) in (13)

ηPp mω31

ω1

Pp

m1

3

1113971

(14)

where m1 mη Moreover the second-speed term dependsupon the DC-link voltage However the upper and lowerlimits of the SPV system are set in between 07 and 09 timesof SPV open-circuit voltage e DC-link voltage is mea-sured with the help of reference and error voltage as [26]

Vl(k) Vdcr(k) minus Vp(k) (15)

where Vldcr is an error in DC-linkreference DC voltage atthe kth instant e error signal of DC-link voltage is passedvia PI controller and the speed term is obtained as follows

ω2(k) ω2(k minus 1) + Kpd Vl(k) minus Vl(k minus 1)1113858 1113859 + KidVl(k)

(16)

where ω2 Kpd and Kpi are the second-speed term pro-portional and integral gains of DC-link voltage compo-nents respectively

Now the reference speed (ωref ) of the motor drive is

ωref ω1 + ω2 (17)

32 Speed Estimation e speed estimation of IM reducesthe cost and provides reliable control as the speed estimationdoes not require any speed sensing device e estimatedmeasured speed (ωesm) of the IM is calculated as follows[27 28]

ωesm ωsy minus ωslr (18)

where ωsyslr is synchronousslip speed However the syn-chronous and slip speed is estimated in terms of IM fluxes asfollows [29 30]

slip speedωslr (1 + σSτ)Lsiq

τ λd minus σLsid( 1113857

synchronous speedωsyn Vq minus iqRs1113872 1113873λd minus Vd minus idRs( 1113857λq

λ2

(19)

where λd Vd minus id(Rs + σSLs) and λq Vq minus iq(Rs + σSLs)σ 1minus L2

mLsLr τ LrRr idq Vdq and λdq dq componentof stator current voltage and flux

33 Vector Control of Induction Motor e vector controlrequires the measured speed and stator currents as shown inFigure 6 e stator currents (iryb) are measured with the

Table 3 Reference voltage corresponding to switching states

Switching states(QbQc)

Reference voltage (vrα + jvrβ) Vector

00 2Vd23 v101 (Vd2 minus Vd1)3 minus j(Vd2 + Vd1)

3

radicv2

10 (Vd2 minus Vd1)3 + j(Vd2 + Vd1)3

radicv3

11 minus2Vd13 v4

ref

1

2

Vdcr

Ip

Vp

Pp

Pp

m1

3

PIAINC

++

-+

Figure 5 Reference speed generation

International Transactions on Electrical Energy Systems 5

-+ SPIC CPIC

Decoupling terms

CPIC SVM

ref

mse

(Lsid +

m)

Lsiq

-+

-+ ++

-+

id

Rr + 2L

rP

RrL

m

idr

iqr

iq

Vd

Vq

dq

toT

r

3PLm

riqr

2Lr

Figure 6 Vector control of induction motor

0 200 400 600

1

2

31 kWm2

075 kWm2

05 kWm2

025 kWm2

0 200 400 600V

p (V)V

p (V)

500

1000

1200

Pp (W

)

I p (A

)

1 kWm2

075 kWm2

05 kWm2

025 kWm2

Figure 7 I-V and P-V characteristics

I rr (W

m2 )

Vp (V

)I p (A

)

02529

35360400440999

10001001

01 02 03 04 05Time (seconds)

(a)

0180

200

200

Vd2

(V)

Vd1

(V)

220

220

180

01 02 03 04 05Time (seconds)

(b)

0

45

T e (Nm

)

0245

T l (Nm

)

-505

I ryb (A

)

0 01 02 03 04 05Time (seconds)

50010001460

Nr (r

pm)

(c)

-200

0

200

Vrn

(V)

-200

0

200

Vyn

(V)

0 01 02 03 04 05Time (seconds)

-200

0

200

Vbn

(V)

(d)

Figure 8 (a) PV output at 1000 Wm2 (b) DC-link voltages across the capacitors S (c) Induction motor performance characteristics at1000Wm2 (d) ree-phase output voltage of FVSI at 1000Wm2

6 International Transactions on Electrical Energy Systems

help of current sensors and the IM measured speed isobtained using speed estimation Moreover the sensedthree-phase stator currents are transformed into d-q com-ponents (idqs) using the coordinate transformations

e error between estimated measured speed (ωmes) andreference speed (ωref ) is tuned using the speed PI controller(SPIC) to generate the required torque reference (Tr)Moreover the field weakening block generates rotor ref-erence flux (λ) and the rotor angle (θ) is achieved by in-tegrating the estimated measured speed So with the help oftorque reference rotor flux and rotor angle the vectorcontrol block produces reference stator dq currents andspace angle (θs) and the corresponding equations are asfollows [31ndash33]

idr Rr + 2LrP

RrLm

λ

iqr 2Lr

3PLmλr

Tr

(20)

where Rr Lmr and P denote rotor resistance mutualrotorinductance and the pair of poles respectively e inte-gration of synchronous speed provides space angle and isgiven as follows

θs 1113946 ωsyn1113872 1113873 dt (21)

Now the error between stator reference currents (idqr)and stator measured currents (idq) are tuned using thecurrent PI controller (CPIC) to update the stator voltages(Vdq) wrt the stator reference frame Moreover the ob-tained stator voltages are transformed into αβ-componentsusing the following equations as follows [34]

Vα

Vβ

⎡⎣ ⎤⎦ cos θs( 1113857 minussin θs( 1113857

sin θs( 1113857 cos θs( 11138571113890 1113891

Vd

Vq

⎡⎣ ⎤⎦ (22)

Now the transformed αβ-components of voltages are fedto the SVM block to generate the desired pulses for theinverter circuit

4 Results and Discussion

e solar PV arrayrsquos static I-V and P-V characteristics areshown in Figure 7e SPV system provides variable voltagecurrent and power at various irradiations

However the input voltage supplied to the IM driveshould be maintained at a rated value otherwise the motorwill significantly impact the starting current and torqueMoreover it also affects the winding insulation life of theinduction motor [35] So maintaining constant DC voltageat the inverter terminals at variable solar irradiation levels

e performances of SPV-fed three-phase four-switchinverter-based induction motor for water pumping systems

I p (A)

Vp (V

)I rr

(Wm

2 )

1452

29

360

400

440500

750

1000

05 1 15Time (seconds)

(a)

05180

200

220180

200

220

1 15Time (seconds)

Vd1

(V)

Vd2

(V)

(b)

024

T e (Nm

)

235

4

T l (Nm

)

-15-06

00615

i ryb (A

)

05 1 15Time (seconds)

1200

1460

Nr (r

pm)

(c)

-2000

200

Vrn

(V)

-2000

200

Vyn

(V)

05 1 15Time (seconds)

-2000

200V

bn (V

)

(d)

Figure 9 (a) PV output during 1000 to 500 Wm2 transition (b) DC-link voltages across the capacitors (c) Induction motor performancecharacteristics during 1000 to 500Wm2 transition (d) ree-phase output voltage of FSVSI during 1000 to 500Wm2 transition

International Transactions on Electrical Energy Systems 7

were tested in MATLAB-Simulink environment at variablesolar irradiationinsolation as shown in Figure 8 At solarirradiation (Irr) of 1000Wm2 the SPV generates the re-quired PV output voltage (Vp) and current (Ip) of 400V and29A respectively as shown in Figure 8(a) Moreover thevoltage across the DC-link capacitors is shown inFigure 8(b) e generated solar power is used to drive theinduction motor and at the starting it produces highcurrents and torques to overcome the inertia and loadtorque Once the IM attains the reference speed of 1460 rpmthe motor torque (Te) load torque (Tl) and motor 3-Φcurrents (iryb) are settled to a steady value of 4Nm 38Nmand 16A respectively as shown in Figure 8(c) Moreoverthe generated three phase stator currents and voltages areshown in Figures 8(c) and 8(d)

At 1 s the solar irradiation is reduced from 1000 to500Wm2 and then the solar PV current falls to 145 A witha slight decrease in solar PV output voltage as shown inFigure 9(a) e voltage across capacitors (Vd1d2) during thetransition decreases slightly and settles to a constant value of200V respectively within a short span as shown inFigure 9(b) However during the transition of solar irradi-ation there is a slight drop in induction motor torque as themotor torque is a function of speed and solar irradiation Asthe solar irradiation is maintained at 500Wm2 the speed ofthe induction motor settles to a steady value corresponding

to the load torque Consequently the motor speed dropsfrom 1460 rpm to 1190 rpm and the motor torque settles to2Nm as shown in Figure 9(c) Moreover the stator threephase currents and voltages are shown in Figures 9(c) and9(d) respectively

To further study the SPV-fed inductionmotor performancesolar irradiation levels are increased e complete system istested with an increase of solar irradiation from 500 to 1000Wm2 and is activated at 2 s en the SPV output current risesfrom 145 A to 29A and during the transition the motortorque and voltage across capacitors increase slightly and settleto steady values as shown in Figure 10 Later the solar irra-diation is maintained at 1000Wm2 then the speed motortorque and load torques are settled to steady values of1460 rpm 4Nm and 38Nm respectively as shown inFigure 10

41 Experimental Results e experimental validation of asolar PV-fed single-stage reduced switch count-based in-verter-driven induction motor for a water pumping systemwith the same simulation parameters is considered More-over the real-time execution is performed using DSPACEDS-1104 solar simulator inverter module 3-Φ IM with DCgenerator (DG) set up and resistor load e water appli-cation load characteristics are incorporated with an IM-DG

I p (A)

Vp (V

)I rr

(Wm

2 )

15145

23

360

400

440500750

1000

2 25Time (seconds)

(a)

Vd2

(V)

15180

200

220

Vd1

(V)

180

200

220

2 25Time (seconds)

(b)

24

6

T e (Nm

)

21838

T l (Nm

)

-2-1

012

i ryb (A

)

15 2 25Time (seconds)

1200

1460

Nr (

rpm

)

(c)

-200

0

200

Vrn

(V)

-200

0

200

Vyn

(V)

15 2 25Time (seconds)

-200

0

200

Vbn

(V)

(d)

Figure 10 (a) PV output during 500 to 1000Wm2 transition (b) DC-link voltages across the capacitors (c) Induction motor performancecharacteristics during 500 to 1000Wm2 transition (d) ree-phase output voltage of FSVSI during 500 to 1000Wm2 transition

8 International Transactions on Electrical Energy Systems

setup with a resistive load as shown in Figure 11 ecomplete parameters associated with the induction motorand solar simulator are given in Appendix

e solar PV-fed single-stage induction motor driveoperates at a solar irradiation of 1000Wm2 and the cor-responding starting and steady-state characteristics areshown in Figure 12 From Figure 12(a) the solar PV gen-erates the required DC voltage and currents of 390 V and

29A respectively Moreover Figure 12(b) shows the voltageacross DC-link capacitors and is maintained constant eIM exhibits high starting currents and torque due to inertiae motor speed starts increasing and reaches to the ratedspeed (1450 rpm) then the torque and current are settled tosteady values of 4N m and 29A respectively as shown inFigure 12(c) Moreover the three-phase stator current andvoltages are shown in Figures 12(d) and 12(e) respectively

PC

ProgrammableDC Supply

IM-DC set

Resistive Load

DSO

Current Probes

Capacitors

PWM PulsesFeedback Signals

Four Switch 3-phase Inverter

DSPACEDS-1104

Figure 11 Experimental setup of SPV-fed FSVSI-fed IM drive

Vp (500 Vdiv)

Ip (2 Adiv)

Time (01 sdiv)

(a)

Vd1

(15 Vdiv)

Vd2

(15 Vdiv)

Time (01 sdiv)

(b)

Nr (1000 rpmdiv)

Time (01 sdiv)

Te (5 Nmdiv)

Tl (2 Nmdiv)

ir (5 Adiv)

(c)

Time (01 sdiv)

ir (5 Adiv)

iy (5 Adiv)

ib (5 Adiv)

(d)

Vrn

(150 Vdiv)

Vyn

(150 Vdiv)

Vbn

(150 Vdiv)

Time (01 msdiv)

(e)

Figure 12 Experimental results of SPV-fed FSVSI-based IM drive at starting condition of (a) PV (b) DC-link capacitors voltage (Vd1 Vd2)and (c) induction motor performance (d) ree-phase starting currents (e) ree-phase stator voltages of the IM

International Transactions on Electrical Energy Systems 9

However the solar irradiation changes from 1000 to500Wm2 then the performance of SPV-fed FSVSI is shownin Figure 13 During the transition the SPV output currentwas reduced to 145 A at constant SPV output voltage and aslight drop in voltage across the capacitors during transitionas shown in Figures 13(a) and 13(b) respectively Moreoverthe motor and load torques drop sharply and settle to steadyvalues once the motor attains the speed corresponding tosolar irradiation of 500Wm2 e motor current also fol-lows the torque path and the respective results are shown inFigure 13(c)

Similarly a sudden increase of solar irradiation from 500to 1000Wm2 is applied and then the corresponding per-formance characteristics of SPV-fed FSVSI-based IM areshown in Figure 14 Due to the increase in solar irradiationthe SPV output current increases from 145A to 29 A atconstant SPV output voltage as shown in Figure 14(a)

However during the transition of solar irradiation thevoltage across the capacitors increases slightly and ismaintained as constant as shown in Figure 14(b) Moreoverthe induction motor torque and current increase sharplyduring the transition period and settle to steady values oncethe motor attains the reference speed as shown inFigure 14(c)

42 Comparison between the Proposed and ConventionalTopology e proposed four-switch inverter-based single-stage SPV-fed sensorless DVC of IM is cost-effective and haslow switching losses A complete comparison of the pro-posed system with the traditional six switch inverter is givenin Table 4 Table 4 shows that the number of PWM pulsesand semiconductor switches without the speed sensor anddriver circuits required for the proposed SPV-fed FSVSI-

Ip (2 Adiv)

Vp (500 Vdiv)

Time (01 sdiv)

(a)

Vd1

(15 Vdiv)

Vd2

(15 Vdiv)

Time (01 sdiv)

(b)

Te (5 Nmdiv)

Tl (2 Nmdiv)

ir (2 Adiv)

Nr (1000 rpmdiv)

Time (01 sdiv)

(c)

Figure 13 Experimental results of SPV-fed FSVSI-based IM drive at the decrement of solar irradiation from 1000Wm2 to 500Wm2 (a)PV (b) DC-link capacitors voltage (Vd1 Vd2) (c) Induction motor performance

Vp (500 Vdiv)

Ip (2 Adiv)

Time (01 sdiv)

(a)

Vd1

(15 Vdiv)

Vd2

(15 Vdiv)

Time (01 sdiv)

(b)

Tl (2 Nmdiv)

ir (2 Adiv)

Nr (1000 rpmdiv)

Time (01 sdiv)

Te (5 Nmdiv)

(c)

Figure 14 Experimental results of SPV-fed FSVSI-based IM drive at the increment of solar irradiation from 500Wm2 to 1000Wm2 (a)PV (b) DC-link capacitors voltage (Vd1 Vd2) (c) Induction motor performance

Table 4 Comparison of conventional and proposed SPV-fed IMD

Item Conventional two-stage system Proposed single-stage systemPWM pulses 7 4DC-link capacitor 2 2Boost converter inductor 1 0Semiconductor switches (IGBTs) 7 4Driver circuits 7 4Speed sensor 1 0

10 International Transactions on Electrical Energy Systems

based IM is less than the conventional SPV-fed SSVSI-basedIM drive

5 Conclusions

e standalone single-stage SPV three-phase sensorlessinduction motor drive for water pumping application withthe help of the proposed four-switch inverter is simulatedand implemented experimentally at various solar irradiationlevels e SPV reference DC-link voltage is obtained usingthe adaptive incremental conductance method and thespeed control of the induction motor drive is performedwith the help of direct vector control Moreover the DC-linkvoltage is maintained as constant using a reference voltagecontrol even at various irradiation levels e control signalto the four-switch inverter is generated using DSPACE DS-1104 directly from the MATLAB environment e overallperformance of an induction motor drive is well suitable forstarting and steady-state even for variable solar insolationlevels Due to the fewer three-phase inverter switches andspeed sensorless operation of IM the overall cost andswitching losses are further reduced significantly comparedto both single- and double-stage conventional inverter to-pology-based speed control methods

Abbreviations

AINC Adaptive incremental conductanceDVC Direct vector controlFSVSI Four-switch voltage source inverterIM Induction motorSSVSI Six-switch voltage source inverterSPV Solar photovoltaicSVM Space vector modulationTr Reference torqueωmse Rotor speed

Appendix

3-Φ IM 075 kW 4 pole 415V 1460 rpm 50HzJ 005 kgminusm2 Lsr 0453H Lm 03636H Rr 863ΩRs 884Ω SPIC (kp 10 ki 004) and CPIC (kp 25ki 4)Programmable DC supply 62000HndashS chroma with5 kW 0ndash600V 85 A

Data Availability

Data sharing is not applicable as no new data were generated

Conflicts of Interest

e authors declare that they have no conflicts of interest

References

[1] Ministry of New and Reneable Energy Government of IndialdquoMNRE year end review-2020rdquo 2020 httpswwwmnregovin

[2] A Narendra N Venkataramana Naik A K Panda andN Tiwary ldquoA comprehensive review of PV driven electricalmotorsrdquo Solar Energy vol 195 pp 278ndash303 2020

[3] K Yadav O S Sastry R Wandhare et al ldquoPerformancecomparison of controllers for solar PV water pumping ap-plicationsrdquo Solar Energy vol 119 pp 195ndash202 2015

[4] V C Sontake and V R Kalamkar ldquoSolar photovoltaic waterpumping systemmdasha comprehensive reviewrdquo Renewable andSustainable Energy Reviews vol 59 pp 1038ndash1067 2016

[5] S Orts-Grau P Gonzalez-Altozano F J Gimeno-Sales et alldquoPhotovoltaic water pumping comparison between direct andlithium battery solutionsrdquo IEEE Access vol 9 pp 101147ndash101163 2021

[6] J R Ferreira Filho F R Freitas Mendes J R Brito SousaC M Sa Medeiros and I R Sousa ldquoPhotovoltaic panel basedpumping system a solution without batteriesrdquo IEEE LatinAmerica Transactions vol 16 no 2 pp 514ndash520 2018

[7] S Jain A K opukara R Karampuri andV T Somasekhar ldquoA single-stage photovoltaic system for adual-inverter-fed open-end winding induction motor drivefor pumping applicationsrdquo IEEE Transactions on PowerElectronics vol 30 no 9 pp 4809ndash4818 2015

[8] B Singh U Sharma and S Kumar ldquoStandalone photovoltaicwater pumping system using induction motor drive withreduced sensorsrdquo IEEE Transactions on Industry Applicationsvol 54 no 4 pp 3645ndash3655 2018

[9] B Mahato K C Jana and P R akura ldquoConstant vfcontrol and frequency control of isolated winding inductionmotor using nine-level three-phase inverterrdquo Iranian Journalof Science and Technology vol 43 no 1 pp 123ndash135 2019

[10] A Munoz-Garcia T A Lipo and D W Novotny ldquoA newinduction motor vf control method capable of high-per-formance regulation at low speedsrdquo IEEE Transactions onIndustry Applications vol 34 no 4 pp 813ndash821 1998

[11] O Chandra Sekhar S Lakhimsetty and A H Bhat ldquoAcomparative experimental analysis of fractional order PIcontroller based direct torque control scheme for inductionmotor driverdquo International Transactions on Electrical EnergySystems vol 31 no 1 Article ID e12705 2021

[12] D Casadei F Profumo G Serra A Tani and D T C Focand ldquoTwo viable schemes for induction motors torquecontrolrdquo IEEE Transactions on Power Electronics vol 17no 5 pp 779ndash787 2002

[13] S Shukla and B Singh ldquoReduced current sensor based solarPV fed motion sensorless induction motor drive for waterpumpingrdquo IEEE Transactions on Industrial Informaticsvol 15 no 7 pp 3973ndash3986 2019

[14] J K Jain S Ghosh S Maity and P Dworak ldquoPI controllerdesign for indirect vector controlled induction motor adecoupling approachrdquo ISA Transactions vol 70 pp 378ndash3882017

[15] A Narendra N V Naik A K Panda and N Tiwary ldquoAnimproved performance of PV-fed IVC induction motor driveusing clamping sequence duty ratio controlrdquo InternationalTransactions on Electrical Energy Systems vol 31 no 11Article ID e13064 2021

[16] A Narendra N Venkataramana Naik and N Tiwary ldquoPV fedseparately excited DC motor with a closed loop speed con-trolrdquo in Proceedings of the 2018 IEEE 8th Power India In-ternational Conference (PIICON) Kurukshetra IndiaDecember 2018

[17] M A Elgendy B Zahawi and D J Atkinson ldquoAssessment ofthe incremental conductance maximum power point tracking

International Transactions on Electrical Energy Systems 11

algorithmrdquo IEEE Transactions on Sustainable Energy vol 4no 1 pp 108ndash117 2013

[18] F Liu S Duan F Liu B Liu and Y Kang ldquoA variable stepsize INC MPPT method for PV systemsrdquo IEEE Transactionson Industrial Electronics vol 55 no 7 pp 2622ndash2628 2008

[19] A K Singh I Hussain and B Singh ldquoDouble-stage three-phase grid-integrated solar PV system with fast zero attractingnormalized least mean fourth based adaptive controlrdquo IEEETransactions on Industrial Electronics vol 65 no 5pp 3921ndash3931 2018

[20] M B De Rossiter Correa C B Jacobina E R C da Silva andA M N Lima ldquoA general PWM strategy for four-switchthree-phase invertersrdquo IEEE Transactions on Power Elec-tronics vol 21 no 6 pp 1618ndash1627 2006

[21] F Blaabjerg D O Neacsu and J K Pedersen ldquoAdaptive SVMto compensate dc-link voltage ripple for four-switch three-phase voltage-source invertersrdquo IEEE Transactions on PowerElectronics vol 14 no 4 pp 743ndash752 1999

[22] R Wang J Zhao and Y Liu ldquoA comprehensive investigationof four-switch three-phase voltage source inverter based ondouble fourier integral analysisrdquo IEEE Transactions on PowerElectronics vol 26 no 10 pp 2774ndash2787 2011

[23] N Venkataramana Naik A Panda and S P Singh ldquoA three-level fuzzy-2 DTC of induction motor drive using SVPWMrdquoIEEE Transactions on Industrial Electronics vol 63 no 3pp 1467ndash1479 2016

[24] B El Badsi B Bouzidi and A Masmoudi ldquoDTC scheme for afour-switch inverter-fed induction motor emulating the six-switch inverter operationrdquo IEEE Transactions on PowerElectronics vol 28 no 7 pp 3528ndash3538 2013

[25] Y Yao P Bustamante and R S S Ramshaw ldquoImprovementof induction motor drive systems supplied by photovoltaicarrays with frequency controlrdquo IEEE Transactions on EnergyConversion vol 9 no 2 pp 256ndash262 1994

[26] K K Prabhakaran A Karthikeyan S Varsha B V Perumaland SMishra ldquoStandalone single stage PV-fed reduced switchinverter based PMSM for water pumping applicationrdquo IEEETransactions on Industry Applications vol 56 no 6pp 6526ndash6535 2020

[27] M Ahmadi Taleshian M Ghanbari and S M RakhtalaldquoSimulation and hardware implementation of a sensorlessmodifiedMPTC for 3φ inductionmotor drivesrdquo InternationalTransactions on Electrical Energy Systems vol 31 no 12Article ID e13118 2021

[28] B Mahato R Raushan and K C Jana ldquoModulation andcontrol of multilevel inverter for an open-end winding in-duction motor with constant voltage levels and harmonicsrdquoIET Power Electronics vol 10 no 1 pp 71ndash79 2017

[29] B K Bose ldquoPower electronics and motor drivesrdquo PowerElectronics in Motor Drives vol 56 no 2 pp 649ndash729 2006

[30] S K Sharma P K Pardhi and R Saxena ldquoSEPIC for solarenergyndashbased sensorless speed control of induction motordriverdquo International Transactions on Electrical Energy Sys-tems vol 31 no 12 Article ID e13166 2021

[31] G K Singh K Nam and S K Lim ldquoA simple indirect field-oriented control scheme for multiphase induction machinerdquoIEEE Transactions on Industrial Electronics vol 52 no 4pp 1177ndash1184 2005

[32] R Chinthamalla R Karampuri S Jain P Sanjeevikumar andF Blaabjerg ldquoDual solar photovoltaic fed three-phase open-end winding inductionmotor drive for water pumping systemapplicationrdquo Electric Power Components and Systems vol 46no 16-17 pp 1896ndash1911 2018

[33] H A Zarchi H M Hesar and M A Khoshhava ldquoOnlinemaximum torque per power losses strategy for indirect rotorflux-oriented control-based induction motor drivesrdquo IETElectric Power Applications vol 13 no 2 pp 267ndash273 2019

[34] P Krause O Wasynczuk and S P Scott Sudhoff Analysis ofElectric Machinery and Drive Systems John Wiley amp SonsFrance UK 2013

[35] B Cagle and F Heredos ldquoe effect of overvoltage on systemperformance using low speed induction motorsrdquo in Pro-ceedings of the Industry Applications Society 38th AnnualPetroleum and Chemical Industry Conference pp 177ndash181Toronto Canada September 1991

12 International Transactions on Electrical Energy Systems