5. Electrical - Ijeeer -Improved Power Factor - Sameera

8/10/2019 5. Electrical - Ijeeer -Improved Power Factor - Sameera

http://slidepdf.com/reader/full/5-electrical-ijeeer-improved-power-factor-sameera 1/10

www.tjprc.org [email protected]

IMPROVED POWER FACTOR AND REDUCTION OF HARMONICS BY USING

DUAL BOOST CONVERTER FOR PMBLDC MOTOR DRIVE

K. SAMEERA 1, A. SRINIVAS 2 & M. V. RAMANA RAO 3

1M. Tech Scholar [PE & ED], Department of Electrical and Electronics Engineering, CVSR College of Engineering,

Hyderabad, Telangana, India2Assistant Professor, Department of Electrical and Electronics Engineering, CVSR College of Engineering,

Telangana, Hyderabad, India3Assistant Professor, Department of Electrical and Electronics Engineering, Osmania University College of Engineering,

Telangana, Hyderabad, India

ABSTRACT

Permanent magnet brushless dc motors (PMBLDCM’s) are preferred motors. This paper presents a Dual boost

converter configuration, control scheme and design of single phase power factor controller for permanent magnet brushless

DC motor (PMBLDCM) drive fed from a single-phase AC mains through a diode bridge rectifier (DBR) followed by a

DC link capacitor, power factor correction (PFC) converter for feeding a voltage source inverter (VSI) is operated only as

an electronic commutator for the PMBLDCM drive. Proposed DUAL BOOST CONVERTER improves the power factor

and decreases the total harmonic distortion (THD) of current at input AC mains. Simulation work is performed by using

MATLAB/SIMULINK software.

KEYWORDS: PMBLDC Motor , Power Factor Correction , THD, VSI , Dual Boost Converter, Speed Controller

INTRODUCTION

BLDC motors are widely used in industries such as Appliances, Consumer, Automotive, Medical,

Aerospace, Industrial Automation Equipment, Robotics, Instrumentation due to its salient features such as the name

implies, BLDC motors do not use brushes for commutation; instead, they are electronically commutated. BLDC motors

have many advantages over brushed DC motors and induction motors. A few of these are:

• Better speed versus torque characteristics

• High dynamic response

• High efficiency

• Long operating life

• Noiseless operation

• Higher speed ranges

In addition, the ratio of torque delivered to the size of the motor is higher, making it useful in applications where

space and weight are critical factors. PMBLDC motor drive by using Dual boost converter control scheme and design of

single phase power factor controller for permanent magnet brushless DC motor (PMBLDCM) drive fed from a

International Journal of Electrical andElectronics Engineering Research (IJEEER)ISSN(P): 2250-155X; ISSN(E): 2278-943XVol. 4, Issue 5, Oct 2014, 43- 52© TJPRC Pvt. Ltd.



44 K. Sameera, A. Srinivas & M. V. Ramana Rao

Impact Factor (JCC): 5.9638 Index Copernicus Value (ICV): 3.0

single-phase AC mains through a diode bridge rectifier (DBR) followed by a DC link capacitor, improves the power factor

and decreases the total harmonic distortion (THD) of current at input AC mains. These power quality problems [3] out of

which the Dual boost converter topology has been extensively used in various ac/dc and dc/dc applications.

In fact, the front end of today’s ac/dc power supplies with power-factor correction (PFC) is almost exclusivelyimplemented with boost topology [4], [7], [8]. The use of Power Factor Correction (PFC) is necessary in order to comply

the recent international standards, such as IEC-1000-3-2 and IEEE-519 – [5].

The PMBLDC motors belong to three-phase synchronous motor family and can be categorized as permanent

magnet synchronous motor (PMSM) and PMBLDCM [14]. The PMSM uses continuous rotor position feedback for

supplying sinusoidal voltages and currents to the motor with sinusoidal back EMF, so that the interaction with sinusoidal

currents produces constant torque with very low ripple. However, the PMBLDCM is supplied by three-phase rectangular

current blocks of 120° electrical duration, in which the back EMF is trapezoidal, with the constant part of the waveform

timed to coincide with the intervals of constant phase current. Therefore PMBLDC motor speed rotor-position information

only at the commutation points, for example, every 60° electrical in the three phases [1].

The PFC converter topologies for PQ improvement in PMBLDC motor drives are designed and their performance

is simulated to provide in-depth understanding on various aspects of these drives to the researchers. A number of PFC

topologies based on DBR followed by DC–DC converters, that is buck, boost, buck–boost, Cuk, SEPIC, Zeta, push–pull,

half bridge, full bridge, have been used to feed PMBLDCM. DBR-based PFC drives are useful in most of the low rating

applications because of simplest control. Boost PFC topologies are the best option for the applications having rated DC

voltage higher than single-phase supply rms voltage. Boost PFC converter forces the drive to draw sinusoidal supply

current in phase with the supply voltage. To obtain unity PF with improved power factor performance, such as reduction of

AC mains current harmonics, reduction of acoustic noise minimum number of components, maximum efficiency etc.,

Moreover, the selection of isolated PFC topologies depends on the drive operating voltage and use of the PMBLDC motor

involving direct human contact such as refrigerator etc.,

MODELLING OF PMBLDC MOTOR

The modelling of PMBLDC motor drive includes the modelling of a speed controller and modelling of PMBLDC

motor as shown in Figure 2. Each of the above components of PMBLDCM drive can be modelled by mathematical

equations and combination of such models represent complete PMBLDCM drive. The modelling of a speed controller is of

prime importance as the performance of the system depends on this controller. Assuming that at instant of time, is

the actual rotor speed, is the reference speed, then the speed error can be calculated as:

A speed controller is used to process this speed error to obtain desired control signal.

SPEED CONTROLLER

The PI controller is used as the speed controller. The PI controller output at instant T (t) is given as,



Improved Power Factor and Reduction of Harmonics by Using Dual Boost Converter for PMBLDC Motor Drive 45


where K p and, KI are the gains of PI speeds controller. A speed controller is used to process this speed error to obtain

desired control signal.

Figure 1: Flow Chart for Speed Controller

PROPOSED PFC TOPOLOGY BLOCK DIAGRAM

Figure 2: Block Diagram of Proposed Topology

In the proposed PFC Topology a Dual Boost Converter is used to boost the input voltage which is fed to a VoltageSource inverter (VSI). The PMBLDC motor is given to the supply from VSI. A speed controller is used in the motor side.

Controller are realised by using Proportional integral (PI) controller. The control loop of VSI-based topology, employed to

execute PFC operation involves inner current loop and outer voltage loop. The complete control scheme block diagram is

shown in figure 2. With a DBR connected to single-phase AC mains, followed by a Dual Boost converter and output ripple

filters.

NEED OF POWER FACTOR IMPROVEMENT

Conventional AC rectification has the following main disadvantages:

• It creates harmonics and electromagnetic interference (EMI).





• It has poor power factor.

• It produces high losses.

• It requires over-dimensioning of parts.

• It reduces maximum power capability from the line.

In order to overcome the above disadvantages we use power factor correction topologies at the supply end.

BOOST CONVERTER

Boost converter is a DC-DC Converter which provides output voltage is greater than input voltage.

Here, the inductor responds to changes in current by inducing its own voltage to counter the change in current, and this

voltage adds to the source voltage while the switch is open. If a diode-and-capacitor combination is placed in parallel to the

switch, the peak voltage can be stored in the capacitor, and the capacitor can be used as a DC source with an output voltage

greater than the DC voltage driving the circuit. This boost converter acts like a step-up transformer for DC signals.

Figure 3: Boost Converter Circuit

DUAL BOOST CONVERTER

In This Dual Boost parallel scheme, we are connecting inductor Lb1 and switch Tb1 are for main PFC while Lb2

and Tb2 are for active filtering. The two purposes i.e. improve the better performance of power factor and reduces the

THD. It involves phase shifting of two boost converters connected in parallel and operating.

Figure 4: Dual Boost Converter Circuit

SIMULATION AND RESULTS

The Simulation results of this paper will shows the different variations such as improvement of power factor and

reduction of harmonics by using different simulation results for without converter, with Boost converter, with Dual Boost

converter.

SIMULATION AND RESULTS FOR WITHOUT CONVERTER

The input current waveform consists of Total Harmonic Distortion. The figure 6 shows THD of input current and





THD percentage is 71.97%. The figure 7 shows power factor value is 0.8 PF. This problem will effect at the supply side

equipments.

Discrete, = 5e-005 .powergui

dc

c1 v+-

v +-

Vi andV rect1

A

B

C

a

b

c

Three-PhaseV- !easure"e#t

Measurements

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

Id

Goto5

Vdc

Goto14

V

pulses

From

Discrete%ate

&i"iter

Dio'e( Dio'e)

Dio'e*Dio'eDio'e1

Input V and IPh

N

V+

V-

Diode Rectifier

Dio'e

D1

D

i +

-

Controller

BLDC

300V/50HZ

Figure 5: Simulation Diagram without Converter for PMBLDC Motor

Figure 6: THD without Converter

Figure 7: Power Factor without Converter

Simulation Results Using Boost Converter

The simulation of PMBLDC motor to improve power factor using boost converter which acts like a step-up

transformer for DC signals is shown in figure 8. The input current waveform consists of Total Harmonic Distortion.

The figure 9 shows THD of input current and THD percentage is 1.51. The figure 10 shows the power factor value0.991.

Discrete, = 5e-005 s.powergui

dcc

c1 v+-

v +-

Vi andV rect1

g

"

a

,

A

B

C

a

b

c


Measurements

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

Id

Goto5

Vdc

Goto14

V

pFrom3

pulses

From

iscrete%ate

&i"iter

Dio'e( Dio'e)

Dio'e*Dio'eDio'e1

Input V and IPh

N

V+

V-

Diode Rectifier

Dio'e

D1

D

i +

-

Controller

BLDC

300V/50HZ

Figure 8: Simulation Diagram using Boost Converter for PMBLDC Motor





Figure 9: THD Using Boost Converter

Figure 10: Power factor using Boost Converter

Simulation Results with Dual Boost Converter for PMBLDC Motor

AC VOLTAGESORCE

Voltage sourcenverter

Discrete, = 5e-005 s.powergui

dc

cc1 v+

-

v +-

Vi andV rect1

g

"

a

,

g

"

a

,

A

B

C

a

b

c


Measurements

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

g

"

C

$

Id

Goto5

Vdc

Goto14

V

pFrom3pFrom1

pulses

From

Discrete%ate

&i"iter

Dio'e( Dio'e)

Dio'e*Dio'eDio'e1

Input V and I

Ph

N

V+

V-

Diode Bridge Rectifier

Dio'e

D1

D

i +

-

Controller

BLDC

300V/50HZ

Figure 11: Simulation Diagram using Dual Boost Converter

When the switches T1 and T2 are ON-state, the proposed topology (Dual Boost) transfers energy from the dc

source at DBR (Diode Bridge rectifier) in to inductances L1 and L2. Then the current divides equally and flow through the

inductor L1of switch1 and inductor L2 of switch2 the output currents flowing through load and C. where C is the

smoothing capacitor connected to VSI through motor drive.

Figure 12: Source Voltage using Dual Boost Converter for BLDC Motor





Figure 13: Source Current Using Dual Boost Converter for BLDC Motor

By using dual boost converter, the source voltage for bldc motor rated voltage 300v shown in figure 12, the source

current for bldc motor 5amps is shown in figure 13.

Figure 14: Stator Current of PMBLDC Motor

Figure 15: Torque of PMBLDC motor Considered

Figure16: Power Factor at the Supply End





Figure 17: Total Harmonic Distortion using Dual Boost Converter

Figure 18: PMBLDC Motor Operated at 1000rpm Speed

The Power factor and total harmonics distortion are be performed better compared with above results by using

dual boost converter . Power factor has been improved value up to 0.9986 near to unity power factor shown in figure 16

and reduction of harmonics has been decreased to 0.7992% are shown in figure 17.

Table 1: Analysis of PF and THD

S. No Circuit Topologies Input Power Factor THD1 Without Boost Converter 0.8 71.972 Boost Converter 0.991 1.513 Dual Boost Converter 0.9986 0.79

CONCLUSIONS

The PFC converter topology for Power quality improvement and reduction of harmonics in PMBLDC motor

drives is designed and their performance is simulated to provide in depth understanding on various aspects of these drives.

The performance of this topology has been evaluated through simulation for validation of their designs. Dual Boost

converter PFC topology is used as this is the best option for applications having rated DC voltage higher than single phase

supply RMS voltage. The PMBLDCM drives incorporating PFC converter can be a milestone towards the widespread

application of these drives. This can be used further improved by using PI and FUZZY controller.

REFERENCES

1. Hussain S. Athab, IEEE Member, P. K. Shadhu Khan, senior IEEE Member, A Cost Effective Method of

Reducing Total Harmonic Distortion (THD) in Single-Phase Boost Rectifier 2007 IEEE.

2. Shikha Singh G. Bhuvaneswari Bhim Singh, Department of Electrical Engineering, Indian Institute of

Technology, Delhi Hauz Khas, New Delhi-110016 INDIA. Multiple Output SMPS with Improved Input PowerQuality.





3. Kung-Hui Fang, and Yu-Ming Chang, High-Power-Factor Soft-Switched Boost Converter IEEE

TRANSACTIONS ON POWER ELECTRONICS, VOL. 21, NO. 1, JANUARY 2006

4. C. Attaianese , Senior Member, IEEE - Predictive Control of Parallel Boost Converters.

5. JFJ van Rensburg, MJ Case and DV Nicolae, Vaal University of Technology, Doorfontein 2028, Johannesburg,

South Africa, Double-Boost DC to DC Converter IEEE.

6. B. SINGH, S. SINGH. : 'Single-phase power factor controller topologies for permanent magnet brush less DC

motor drives', lET Power Electron., 2010, Vol. 3,Iss. 2, pp. 147-175

7. MILLER T. lE: 'Brushless permanent magnet and reluctance motor drive' (Clarendon Press, Oxford, 1989

8. DUBEY G. K: 'Power semiconductor controlled drives' (Prentice Hall, New Jersey, 1989)

9. KRISHNAN R: 'Electric motor drives: modelling, analysis and control' (Pearson Education, India, 2003)

10. RASHID M. H: 'Power electronics: circuits, devices and applications' (Pearson Education, India, 2004)

AUTHORS DETAILS

K. SAMEERA received her B. Tech degree from Bhoj Reddy Engineering College in the year 2010, and she is

pursuing his Masters through GATE in Power Electronics & Electrical drives from C. V. S. R College of engineering,

Hyderabad.

A. SRINIVAS did his M. Tech from NIT JAIPUR. He has teaching experience of 6years. Presently he is an

Assistant professor of EEE Dept. in C. V. S. R Engineering College.

M. V. RAMANARAO did his M. Tech from JNTU Hyderabad. He has teaching experience of 14 years.

Presently he is an Assistant professor of EEE Dept. in OSMANIA UNIVERSITY Engineering College.



Date post:	02-Jun-2018
Category:	Documents
Upload:	tjprc-publications
View:	216 times
Download:	0 times

5. Electrical - Ijeeer -Improved Power Factor - Sameera

Documents