International Journal of Engineering Trends and Technology ... · (neutral clamped) inverter,...

International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 1 - Jun 2014

ISSN: 2231-5381 http://www.ijettjournal.org Page 27

Design and Simulation of Single-Phase Three-Level,

Four-Level and Five-Level Inverter Fed Asynchronous

Motor Drive with Diode Clamped Topology

Gerald Diyike1, Aniekan 0ffiong

2, Daniel Nnadi C

3

1 Department of Mechanical Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B 7267, Abia State, Nigeria 2 Department of Mechanical Engineering, University of Uyo, Uyo, P.M.B. 1017, Akwa Ibom State, Nigeria

3 Departments of Mechanical Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B 7267, Abia State, Nigeria

ABSTRACT - This paper deals with study of single-phase three-level,

four-level and five-level inverter fed asynchronous motor drive. Both

three-level, four-level and five-level inverters are realized by diode

clamped inverter topology. The poor quality of voltage and current of

a convectional inverter fed asynchronous motor is due to presence of

harmonic contents and hence there is significant level of energy

losses. The multilevel inverter is used to reduce the harmonic

contents. The inverter with a large number of steps can generate a

high quality voltage waveform. The higher inverter levels can be

modulated by comparing a sinusoidal reference signal and multiple

triangular carrier signals by the means of pulse width modulation

technique. The simulation of single-phase three-level, four-level and

five-level inverter fed asynchronous motor model is done using

(The math Works, Natick, Massachusetts,

USA). The Fast Fourier Transform (FFT) spectrums of the outputs

are analyzed to study the reduction in the harmonic contents.

Keywords - Asynchronous Motor, Multi-level inverters, pulse width modulation, Total harmonic distortion.

I. INTRODUCTION

Adjustable speed drives are the vital and endless demand of the industries and researchers. Asynchronous motors are widely

used in the factories and industries to control the speed of

conveyor systems, blower speeds, machine tool speeds and

applications that require adjustable speed controls. Thus, single-

phase asynchronous motors are extensively used for smaller

loads, such as household appliances like fans, water pumps. In

many industrial applications, traditionally, DC motors, provide

excellent speed control for acceleration and deceleration with

effective and simple torque control. The supply of a DC motor

connects directly to the field of the motor allows for precise

voltage control, which is necessary with speed and torque control applications. DC motors perform better than AC motors

on the some traction equipment. They are also used for mobile

equipment like golf cart, quarry and mining equipment. DC

motors are conveniently portable and well suited to special

applications, such as industrial tools and machinery that is not

easily run from remote sources. But, they have inherent demerit

of commutator and mechanical brushes, which undergo wear

and tear with the passage of time. In most cases, AC motors are

preferred to DC motors, in particular, an asynchronous motor

due to its simple design, low cost, reliable operation, easily

found replacements or low maintenance, variety of mounting styles, many environmental enclosures, lower weight, higher

efficiency, improved ruggedness. All these and more features

make the use of induction motor compulsory in many areas of

industrial applications. The main demerit of AC motor, when

compared with DC motor, is that its speed is more difficult to

control. AC motors can be equipped with variable

frequency/PWM drives, which provide smooth turning moment, or torque, at low speeds and complete control over the speed of

the motor up to its rated value. Variable frequency drives

improves speed control, but do create losses with reduced power

quality [1].

The advancement in Power Electronics and semiconductor technology has triggered the development of high power and

high speed semiconductor devices in order to achieve a smooth,

continuous and step less variation in motor speed. Applications

of solid state converters/inverters for adjustable speed induction

motor drive are wide spread in electromechanical systems for a

large spectrum of industrial systems,[2],[3],[4]. As far as

convectional two-level inverter is concerned, it exhibits many

problems when used in high power application [5], [6]. Poor

quality of output current and voltage of an asynchronous motor

fed by a classical/ convectional two-level inverter configuration is due to the presence of harmonic content. The presence of

significant amount of harmonic makes the motor to suffer from

severe torque pulsations, especially at low speed, which

manifest themselves in cogging of the shaft. It will also causes

undesired motor heating and Electromagnetic interference [7].

Minimization in harmonics calls for large sized filter, resulting

increased size and the cost of the system. The advancements in

http://www.ijettjournal.org/


ISSN: 2231-5381 http://www.ijettjournal.org 8

the field of power electronics and microelectronics made it

possible to reduce the magnitude of harmonics with multilevel

inverters, in which the number of levels of the inverters are

increased rather than increasing the size of the filters [8]. Nowadays, multilevel inverters have been gained more attention

for high power application in recent years which operate at high

switching frequencies while producing lower order harmonic

components. Multilevel inverter not only achieves high power

ratings, but also enables the use of renewable energy sources

[9].

In this paper Single-phase three-level, four-level, and five-level inverter fed asynchronous motor drive are designed and

simulated. Both the different levels are realized by using diode

clamped multilevel inverter topology. The simulations are done

using Matlab/Simulink/SimPowerSystems software with PWM

control. The FFT spectrum for the output voltages and currents

are analyzed to study the reduction in the harmonic contents.

II. MULTILEVEL INVERTER

Multilevel inverters have drawn tremendous interest in the power industry applications. They present a new set of features

that are well suited for use in reactive power compensation.

Multilevel inverters will most importantly reduce the magnitude

of harmonics and increases the output voltage and power without the use of step-up transformer. Numerous multilevel

inverters topologies have been proposed during the last

decades. Modern research, have involved novel inverter

topologies and unique modulation techniques [10]. Basically,

three different major multilevel inverter topologies have been

reported in the literature, which includes: diode clamped

(neutral clamped) inverter, flying capacitors inverter, and

cascaded H-bridge. Multilevel inverter presented in this paper

consists of diode clamped inverter topology connected to single

phase asynchronous motor. The general function of this

multilevel inverter is to synthesize a desired voltage from several DC sources.

A. SINGLE-PHASE THREE-LEVEL, FOUR-LEVEL AND FIVE-LEVEL INVERTER CIRCUIT CONFIGURATIONS

USING DIODE CLAMPED TOPOLOGY

The neutral point inverter proposed by Nabae, and Akagi in

1981 was essentially a three-level, diode-clamped inverter [10].

The diode-clamped inverter provides multiple voltage levels

through connection of the phases to a series bank of capacitors

[11]. The main concept of this type of multilevel inverter

topology is to use diodes to limit the power devices voltage

stress. The voltage over each capacitor and each switch is . A

single-phase full bridge -level inverter needs ( voltage

source, switching devices and 8( diodes.

This topology can be extended to any number of levels by

increasing the number of capacitor banks. Diode clamped

multilevel inverter topology can be discussed under a single-

phase structures. Fig. 1 show single-phase three-level structure

of Diode Clamped Inverter.

DC

2dc

V

V dc

2dc

V

C1

C2

Da2T a2ga2

Da1

_______

1T aga1

__

Db2Tb2g

b2

iOva vb

Da1T a1ga1

Db1Tb1gb1

Da2

_______

2T a

ga2

__

Dac1

Dac2

Dbc1

Db1

_______

1Tbgb1

__

Dbc2

Db2

____

___

2Tbgb2

__

AC

Fig. 1 Power circuit for Single-phase, three-level diode clamped inverter

As shown in the fig. 1 above, a single-phase full bridge three-

level diode clamped inverter consists of two bulk capacitor (

and ), four clamping diodes ( , , and ) ,

eight antiparallel diodes ( , , ,

, , , ,

and ) and eight power switches ( , ,

, , ,

, , and

). For a given DC link voltage , the two

capacitors and are connected in series across the DC link

input. They split the DC link voltage across the capacitors with a

constant value equals to

. The clamping diodes ,

, and are used to maintain the potential across the

switches. Thus, the voltage stress of each switch is limited to

one capacitor voltage

. For a single-phase three-level full

bridge diode clamped inverter, the voltage across the output of

the two legs can be equal to 0,

and . Fig. 2 shows a

Single-phase four-level structure of Diode Clamped Inverter.




DC

3

DCV

VDC

3

DCV

C1

C2

Da1

_______

1Ta

ga1

__

Db2Tb2

gb2

iOva vb

Da1Ta1

ga1

Db1Tb1

gb1

Da2

_______

2Ta

ga2

__

Dac1

Dac2

Dbc1

Db1

_______

1Tb

gb1

__

Dbc2

Db2

_______

2Tb

gb2

__

Da3Ta3

ga3

Da2Ta2

ga2

Da3

_______

3Ta

ga3

__

Db3Tb3

gb3

Db3

_______

3Tb

gb3

__

Dac1

Dac2

Dac1

Dac23

DCVC3

AC

Fig. 2 Power circuit for Single-phase, four-level diode clamped inverter

The single-Phase Structure of diode clamped four-level inverter is illustrated in Fig. 2. DC voltage source is connected

to the inverter circuit through three capacitors connected are

connected in series. They split the DC link voltage across the

capacitors with a constant value equals to

. Thus, the voltage

stress of each switch is limited to one capacitor voltage

. For

a single-phase four-level full bridge diode clamped inverter, the

voltage across the output of the two legs can be equal to 0,

,

and . Fig. 3 shows a Single-phase five-level structure of

Diode Clamped Inverter.

DC

4

DCV

V DC

4

DCV

C1

C2

Da1

_______

1Ta

ga1

__

Db2Tb2

gb2

iOva vb

Da1Ta1

ga1 Db1Tb1

gb1

Da2

_______

2Ta

ga2

__

Dac1

Dac2

Dbc1

Db1

_______

1Tb

gb1

__

Dbc2

Db2

_______

2Tb

gb2

__

Da3Ta3

ga3

Da2Ta2

ga2

Da3

_______

3Ta

ga3

__

Db3Tb3

gb3

Db3

_______

3Tb

gb3

__

Dac1

Dac2

Dac1

Dac2

4

DCVC3

Da4Ta4

ga4

Db4Ta4

ga4

Da4

_______

4Ta

ga4

__

Db4

_______

4Tb

gb4

__

4

DCVC4

AC

Fig. 3 Power circuit for Single-phase, five-level diode clamped inverter

Finally, single-phase structure of diode clamped five-level inverter is illustrated in Fig. 3. DC voltage source is connected

to the inverter circuit through four dividing capacitors which are

connected in series. They split the DC link voltage across the

capacitors with a constant value equals to

. Thus, the voltage

stress of each switch is limited to one capacitor voltage

. For

a single-phase five-level full bridge diode clamped inverter, the

voltage across the output of the two legs can be equal to 0,

,

,

and .

B. ASYNCHRONOUS MOTOR DRIVE

Synchronous speed of Asynchronous Motor varies directly proportional to the supply frequency. Hence, by changing the

frequency, the synchronous speed and the motor speed can be

controlled below and above the normal full load speed. The

voltage induced in the stator, E is directly proportional to the

product of slip frequency and air gap flux. The Asynchronous

Motor terminal voltage can be considered proportional to the

product of the frequency and flux, if the stator voltage is

neglected. Any reduction in the supply frequency without a

change in the terminal voltage causes an increase in the air gap flux. Asynchronous motors are designed to operate at the knee




point of the magnetization characteristic to make full use of the

magnetic material. Therefore the increase in flux will saturate

the motor. This will increase the magnetizing current, distort the

line current and voltage, increase the core loss and the stator copper loss, and produce a high pitch acoustic noise. While any

increase in flux beyond rated value is undesirable from the

consideration of saturation effects, a decrease in flux is also

avoided to retain the torque capability of the motor. Therefore,

the pulse width modulation (PWM) control below the rated

frequency is generally carried out by reducing the machine

phase voltage, V, along with the frequency in such a manner

that the flux is maintained constant. Above the rated frequency,

the motor is operated at a constant voltage because of the

limitation imposed by stator insulation or by supply voltage

limitations [1]. In this paper split-phase single-phase Asynchronous Motor is used as inverter load throughout the

simulation process. Fig. 4 shows Split-phase Single-phase

Asynchronous Motor.

Fig. 4 Split-phase single-phase asynchronous motor

A three-phase symmetrical induction motor upon losing one of its stator phase supplies while running may continue to

operate as essentially a single-phase motor with the remaining

line-to-line voltage across the other two connected phases.

When the main winding coil is connected in parallel with ac

voltage, as in the split-phase single-phase asynchronous motor

of fig. 4, the current of the auxiliary winding, , leads of

the main winding. For even a larger single-phase induction

motor, that lead can be further increased by connecting a

capacitor in series with the auxiliary winding, this arrangement

brings about a Capacitor-start single-phase asynchronous motor.

III. SIMULATION MODEL AND RESULTS

Multilevel inverter fed asynchronous motor drive inverter is implemented in MATLAB SIMULINK which is shown in Fig.

5. The MATLAB SIMULINK model of Single-phase full bridge

of Diode Clamped Multilevel inverter using three-level diode

clamped configuration is shown in Fig. 5.

Fig. 5 Matlab/Simulink model of multilevel asynchronous motor drive.

The single-phase three-level diode clamped inverter output voltage after feeding to asynchronous motor is shown in Fig. 6.

The stator main winding output current with respect to single-

phase is shown in Fig. 7. The Variation in speed is shown in Fig. 8. The machine starts at no load and then at t=2.0 sec, once the

machine has reached its steady state, the load torque is increased

to its nominal value (4 N.m) in 1.0 sec. The speed increases and

settles at 1500 rpm without torque load and drops to 1450 rpm

when loaded with torque load. The Electromagnetic torque is

shown in Fig. 10. The Fast Fourier Transform (FFT) analysis is

done for the output voltage and stator main winding current and

the corresponding spectrum is shown in Fig. 11 and Fig. 12

respectively. It can be seen that the magnitude of fundamental

voltage for three-level inverter fed asynchronous motor drive is

207.6 Volts. The total harmonic distortion is 3.04 percent and the magnitude of fundamental current is 28.6 Amperes. The

total harmonic distortion is 1.43 percent.

powergui

Discrete,

Ts = 5e-005 s.

Single Phase

Asynchronous Machine

Rating 0.25Hp, 220 V,

50Hz, 1500 rpm

split

phase

Tm

m

Scope

Multilevel

Inverter System

g

Va

Vb

Load Torque

4Nm

Inverter Output

Voltage Measurement

v+-

Gain

-K-

Firing Signal

Generator

Firing Pulses

<Rotor speed (rad/s or pu)>

<Main winding current Ia (A or pu)>

<Electromagnetic torque Te (N*m or pu)>




Fig. 6 Matlab/Simulink model of Single-phase Three-level Diode Clamped Inverter

Fig. 7 Single-phase three-level inverter output Voltage

Fig. 8 Single-phase three-level inverter output Stator Main winding current

powergui

Discrete,

Ts = 5e-005 s.

Vtri4

Vtri3

Vtri2

Vtri1

Vref

Tb 33

g CE

Tb 3

g CE

Tb 22

g CE

Tb 2

g CE

Ta33

g CE

Ta3

g CE

Ta22

g CE

Ta2

g CE

Single Phase


split

phase

Tm

m

ScopePulse

Generator

NOT

NOT

NOT

NOT

[gb1]

[Notgb 1]

[gb2]

[Notgb 2]

[Notga 1]

[ga1]

[ga2]

[Notga 2]

From 9

[Io ]

From 8

[Vo]

From 7

[gb1]

From 6

[Notgb 1]

From 5

[gb2]

From 4

[Notgb 2]

From3

[Notga 1]

From 2

[ga1]

From 1

[ga2]

From

[Notga 2]

Embedded

MATLAB Function

SIN

T1

T2

T4

T5

a

b

d

e

fcn

DC Voltage 1

DC Voltage

D5

D4

D1

D0

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

-200

-100

0

100

200

Time (s)

Ou

tpu

t V

olt

ag

e

0 10 20 30 40 50 600

5

10

15

20

25

30

Harmonic order

Fundamental (50Hz) = 203.4 , THD= 1.73%

Mag (

% o

f F

undam

enta

l)

0 1 2 3 4 5 6 7 8 9 10

-20

-10

0

10

20

30

Time (s)

Ou

tpu

t S

tato

r

Main

win

din

g C

urren

t (A

)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)




Figure 9: Variation in speed

Fig. 10 Variation in electromagnetic torque

Fig. 11 FFT analysis of voltage

Fig. 12 FFT analysis of current

The MATLAB SIMULINK model of Single-phase of four-level Diode Clamped Inverter configuration is shown in Fig. 13

0 1 2 3 4 5 6 7 8 9 100

500

1000

1500

Time (s)

Ro

tor S

peed

(rp

m)

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

Mag (

% o

f F

undam

enta

l)

Frequency (Hz)

0 1 2 3 4 5 6 7 8 9 10

-10

0

10

Time (s)

Ele

ctr

om

ag

neti

c

torq

ue (

Nm

)

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

Mag (

% o

f F

undam

enta

l)

Frequency (Hz)

0 1 2 3 4 5 6 7 8 9 10

-200

0

200

Selected signal: 500 cycles. FFT window (in red): 20 cycles

Time (s)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)

0 1 2 3 4 5 6 7 8 9 10

-20

-10

0

10

20

30

Time (s)

Ou

tpu

t S

tato

r

Main

win

din

g C

urr

en

t (A

)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)




Fig. 13 Matlab/Simulink model of single-phase four-level diode clamped inverter

The single-phase four-level diode clamped inverter output voltage after feeding to asynchronous motor is shown in Fig.

14. The output stator main winding current with respect to

single-phase is shown in Fig. 15. The Variation in speed is

shown in Fig. 16. The speed increases and settles at 1500 rpm

without torque load and drops to 1450 rpm when loaded with

torque load of 4 Nm. The Electromagnetic torque is shown in Fig. 17. The Fast Fourier Transform (FFT) analysis is done for

the voltage and output stator main winding current and the

corresponding spectrum is shown in Fig. 18 and Fig. 19


voltage for four-level inverter fed asynchronous motor drive is 209.5 Volts. The total harmonic distortion is 2.32 percent and

the magnitude of fundamental current is 28.74 Amperes. The


Fig. 14 Single-phase four-level inverter output voltage

powergui

Discrete,

Ts = 5e-005 s.

Vtri6

Vtri5

Vtri4

Vtri 3

Vtri2

Vtri1

Vref

Tb 33

g CE

Tb 3

g CE

Tb 22

g CE

Tb 2

g CE

Tb 11

g CE

Tb 1

g CE

Ta33

g CE

Ta3

g CE

Ta22

g CE

Ta2

g CE

Ta11

g CE

Ta1

g CE

Single Phase


split

phase

Tm

m

Pulse

Generator

NOT

NOT

NOT

NOT

NOT

NOT

[gb2]

[NOTgb 2] [gb3]

[NOTgb 3]

[NOTga 1]

[ga1]

[NOTga 2]

[ga2]

[gb1]

[NOTgb 1]

[NOTga 3]

[ga3]

From 9

NOTgb 1]

From 8

[gb3]

From 7

[gb2]

From 6

[gb1]

From 5

NOTga 3]

From 4

NOTga 2]

From 3

NOTga 1]

From 2

[ga3]

From 13

[Io ]

From 12

[Vo]

From 11

NOTgb 3]

From 10

NOTgb 2]

From 1

[ga2]

From

[ga 1]

Embedded

MATLAB Function

SIN

T1

T2

T3

T4

T5

T6

a

b

c

d

e

f

fcn

DC Voltage 3

DC Voltage 2

DC Voltage 1

D7

D6

D5

D4

D3

D2

D1

D0

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

-200

-100

0

100

200

Time (s)

Ou

tpu

t V

olt

ag

e (

V)

0 100 200 300 400 500 6000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)




Fig. 15 Single-phase four-level inverter output stator main winding current

Fig. 16 Variation in speed



Fig.19 FFT analysis of current

0 1 2 3 4 5 6 7 8 9 10

-20

0

20

Time (s)

Ou

tpu

t S

tato

r

Main

win

din

g C

urren

t (A

)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)

0 1 2 3 4 5 6 7 8 9 100

500

1000

1500

Time (s)

Ro

tor

Sp

eed

(rp

m)

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

Mag (

% o

f F

undam

enta

l)

Frequency (Hz)

0 1 2 3 4 5 6 7 8 9 10

-10

0

10

Time (s)

Ele

ctr

om

ag

neti

c

To

rqu

e (

Nm

)

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

Mag (

% o

f F

undam

enta

l)

Frequency (Hz)

0 1 2 3 4 5 6 7 8 9 10

-200

0

200


Time (s)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

amen

tal)

0 1 2 3 4 5 6 7 8 9 10

-20

0

20

Time (s)

Ou

tpu

t S

tato

r

Mai

n w

ind

ing

Cu

rren

t (A

)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

amen

tal)




The MATLAB SIMULINK model of Single-phase of five-level Diode Clamped Inverter configuration is shown in Fig. 20

Fig. 20 Matlab/Simulink model of single-phase five-level diode clamped inverter

The single-phase five-level diode clamped inverter output

voltage after feeding to asynchronous motor is shown in Fig.

21. The output stator main winding current with respect to single-phase is shown in Fig. 22. The Variation in speed is

shown in Fig. 23. The speed increases and settles at 1500 rpm

without torque load and drops to 1450 rpm when loaded with

torque load of 4 Nm. The Electromagnetic torque is shown in

Fig. 24. The Fast Fourier Transform (FFT) analysis is done for

the voltage and output stator main winding current and the

corresponding spectrum is shown in Fig. 25 and Fig. 26


voltage for five-level inverter fed asynchronous motor drive is

208.2 Volts. The total harmonic distortion is 1.70 percent and

the magnitude of fundamental current is 28.58 Amperes. The


powergui

Discrete,

Ts = 5e-005 s.

Vtri8

Vtri7

Vtri6Vtri5

Vtri 4

Vtri 3

Vtri 2

Vtri1

Vcontrol

Tb 4

g CE

Tb 3

g CE

Tb 2

g CE

Tb 1

g CE

Ta4

g CE

Ta3

g CE

Ta2

g CE

Ta1

g CE

Single Phase


split

phase

Tm

mPulse

Generator

NTb 4

g CE

NTb 3

g CE

NTb 2

g CE

NTb 1

g CE

NTa 4

g CE

NTa 3

g CE

NTa 2

g CE

NTa1

g CE

NOT

NOT

NOT

NOT

NOT

NOT

NOT

NOT

[gb4]

[NOTgb 4]

[NOTga 1]

[ga1]

[NOTga 2]

[ga2]

[NOTga 3]

[ga3]

[gb1][NOTgb 1]

[gb2]

[NOTgb 2]

[gb3]

[NOTgb 3]

[NOTga 4]

[ga4]

From 9

NOTgb 3]

From 8

NOTgb 4]

From 7

NOTga 4]

From 6

NOTga 3]

From 5

NOTga 2]

From 4

NOTga 1]

From 3

[ga 4]

From 2

[ga3]

From 15

[gb 1]

From 14

[gb2]

From 13

[gb3]

From 12

[gb4]

From 11

NOTgb 1]

From 10

NOTgb 2]

From 1

[ga 2]

From

[ga 1]

Embedded

MATLAB Function

SIN

T1

T2

T3

T4

T5

T6

T7

T8

a

b

c

d

e

f

g

h

fcn

DC Voltage 3

DC Voltage 2

DC Voltage 1

DC Voltage

D9

D8

D7

D6

D5

D4

D3

D2

D11

D10

D1

D0

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

-200

-100

0

100

200

Time (s)

Ou

tpu

t V

olt

ag

e (

V)

0 50 100 150 200 250 300 350 400 450 5000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)




Fig. 21 Single-phase five-level inverter output voltage

Fig. 22 Single-phase five-level inverter output stator main winding current

Fig. 23 Variation in speed



0 1 2 3 4 5 6 7 8 9 10

-20

0

20

Time (s)

Ou

tpu

t S

tato

r

Main

win

din

g C

urren

t (A

)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)

0 1 2 3 4 5 6 7 8 9 100

500

1000

1500

Time (s)

Ro

tor

Sp

eed

(rp

m)

0 500 1000 1500 2000 2500 30000

500

1000

1500

2000

Frequency (Hz)


Mag (

% o

f F

undam

enta

l)

0 1 2 3 4 5 6 7 8 9 10

-10

0

10

Time (s)

Ele

ctr

om

ag

neti

c

To

rqu

e (

Nm

)

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

Mag (

% o

f F

undam

enta

l)

Frequency (Hz)

0 1 2 3 4 5 6 7 8 9 10

-200

0

200


Time (s)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

amen

tal)




The results are tabulated in Table I below:

TABLE I

THE ANALYSIS OF THREE-LEVEL, FOUR-LEVEL and FIVE- LEVEL DIODE

Parameters Diode Clamped Multilevel Inverter

Three-level Inverter Four-level

Inverter

Five-level

Inverter

Voltage

Level (V)

207.6 209.5 208.20

THD for

Voltage (%)

3.04 2.32 1.70

Current

Level (A)

28.6 28.74 28.58

THD for

Current (%)

1.43 0.99 0.84

Fig. 26 FFT analysis of Current

IV. CONCLUSIONS

Three-level, Four-level and Five-level Diode Clamped inverter fed asynchronous motor drive are simulated using the

blocks of Matlab/Simulink/SimPowerSystems. The results of

three-level, four-level and five-level systems are compared. It is observed that the total harmonic distortion produced by the five-

level inverter system is less than those of three-level and four-

level inverter fed drive system. Therefore the heating due to

five-level inverter system is less than those of three-level and

four-level inverter fed drive system. The switching losses due to

five-level inverter system is higher than those of three-level and

four-level inverter fed system because of high number of power

switches involved in the design. The simulation results of

voltage, current, electromagnetic torque, speed and spectrum are

presented. This drive system can be used in industries where

adjustable speed drives are required to produce output with reduced harmonic content. The scope of this work is the

modeling and simulation of three-level, four-level and five-level

inverter fed asynchronous motor drive systems. An Improved

Multilevel topology will be used to drive the asynchronous

motor in future work. Five-level or higher level inverter system

is a viable alternative since it has better performance.

REFERENCES

[1] Manasa, S., Balajiramakrishna, S., Madhura, S. and Mohan, H. M.,

“Design and Simulation of Three Phase Five Level and Seven Level

inverter fed Induction Motor Drive with Two Cascaded H-Bridge

Configuration”, International Journal of Electrical and Electronics

Engineering (IJEEE), , vol. 1, pp. 2231-5284 2012.

[2] Tolbert, L. M., Peng, F. Z. and Habetler, T. G., “Multilevel Converters for

Large Electric Drives”, IEEE Transactions on Industry Applications, vol.

35, no. 1, pp. 36–44, 1999.

[3] Pandian, G. and Rama, R. S., “Implementation of Multilevel Inverter-Fed

Induction Motor Drive”, Journal of Industrial Technology, vol. 24, pp.

109–119, 2008.

[4] Neelashetty, Kashappa and Ramesh, Reddy, “Performance Of Voltage

Source Multilevel Inverter – Fed Induction Motor Drive Using

Simulink”, ARPN Journal of Engineering and Applied Sciences, vol. 6,

no. 6, pp. 1819-6608, 2011.

0 1 2 3 4 5 6 7 8 9 10

-20

0

20

Time (s)

Ou

tpu

t S

tato

r

Main

win

din

g C

urren

t (A

)

0 500 1000 1500 2000 2500 30000

20

40

60

80

100

Frequency (Hz)


Mag

(%

of

Fu

nd

am

en

tal)




[5] Rodríguez, J., Lai, J. S. and Peng, F. Z., “Multilevel inverters: A Survey

of Topologies, Controls, and Applications”, IEEE Transactions on

Industrial Electronics, vol. 49, no. 4, pp. 724-738, 2002.

[6] Lai, J. S. and Peng, F. Z., “Multilevel Converters-a New Breed of Power

Converters”, IEEE Transactions on Industry Applications, vol. 32, no.

3, pp. 509-517, 1996.

[7] Shivakumar, E.G., Gopukumar, K.., Sinha S. K. and Ranganathan, V.T.,

“Space Vector PWM Control of Dual Inverter Feed-open-end

Winding induction Motor Drive”, IEEE APEC Conf., vol. 1, pp. 399-

405, 2001

[8] Dixon, J. and Moran, L.,” High-level Multi-Step Inverter Optimization

using a Minimum number of Power Transistors “, IEEE Tran. Power

Electron, vol. 21, no.23, pp. 30-337, 2006.

[9] Murugesan, M., Sakthivel, R., Muthukumaran, E and Sivakumar, R.

“Sinusoidal PWM Based Modified Cascaded Multilevel Inverter”,

International Journal of Computational Engineering Research, vol. 2,

no. 2, pp. 529-539, 2012.

[10] Surin, Khomfoi and Tolbert, L. M., “Multilevel Power Converters”,

University of Tennessee, www.google.com/m/url/channel=n&w

client/wed.eecs.utk.edu/~tolbert/publications/multilevel_book_chapter.

pdf, 2012.

[11] Kith Corzine, “Operation and design of Multilevel Inverters”,

Developed for the office of Naval research, 2003.


http://www.google.com/m/url/channel=n&w

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