bridgeless pfc cuk derived converter fed bldc motor · pdf filecuk derived converter ... boost...

International Journal of Research and Engineering Volume 2, Issue 4

57 http://www.ijre.org

ISSN 2348-7852 (Print) | ISSN 2348-7860 (Online)

Bridgeless PFC Cuk Derived Converter Fed BLDC Motor with PID and Fuzzy Logic

Controller 1J. Pearly Catherine,

2R. Balamurugan

Department of Power Electronics and Drives, K.S.Rangasamy College of Technology (Autonomous)

K.S.R Kalvi Nagar, Tiruchengode, Namakkal, Tamilnadu, India, Ph./Fax: 04288 274741-44/04288 274860 1J. Pearly Catherine, R. Balamurugan, email:

[email protected],

[email protected]

Abstract—A bridgeless single phase ac-dc rectifier based

Cuk derived converter topology fed BLDC motor is

proposed to improvepower factor at the AC mains near to

the unity with low THD for PFC applications. It utilizes one control signal over the whole line cycle. In addition, the

proposed converter exhibits low inrush current and low

magnetic emissions as classical Cuk topology. The partial

elimination of diodes in DBR in the bridgeless topology

results in lower conduction losses as compared with

conventional Cuk converter. The proposed method is

simulated in MATLAB/Simulink with PID and fuzzy logic

controller for precise speed control. Simulation results are

presented along with the theoretical analysis.

Keywords— Power Factor Correction(PFC), Total

Harmonic Distortion (THD), Diode Bridge

Rectifier(DBR), Cuk Derived Converter, Fuzzy Logic

Control (FLC)

Introduction

BLDC motors are most popular in household appliances

over the last few decades [1-3]. As the name indicates, it has

no brushes for commutation thus eliminates the

disadvantages of wear and tear in conventional DC motors.

The switches are electronically commutated with the help of

rotor position detected using hall sensors. Hence the BLDC

motor is also known as electronically commutated motor [4-5]. Power quality problems have become important issues in

these motors due to the recommended limits of harmonics in

supply current by various international power quality

standards such as the International Electro technical

Commission (IEC) 61000-3-2 [6]. Combination of motor

with inverter is the BLDC motor setup.BLDC motor is

powered with two level inverter.The two level inverter

composed of 6 switches. Based on rotor position obtained

from hall sensors/optical encoders/resolvers, the power

electronic switches are commutated.

A BLDC motor when fed by a diode bridge rectifier

(DBR) has higher conduction losses. The high conduction loss caused by the high forward voltage drop of the bridge

diode begins to degrade the overall system efficiency.The

heat generated within the bridge rectifier may destroy the

individual diodes. Hence, it becomes necessary to utilize a

bridge rectifier with higher current handling capability or

heat dissipating characteristics. This increases the size and

cost of the power supply, which is unacceptable for an

efficient design. Bridgeless topologies seems to be the best

solution for reducing the conduction and switching losses of

the converter.

Several bridgeless topologies are introduced. Bridgeless boost converter requires an additional converter or an

isolation transformer to step down the voltage [10-

11].Bridgeless buck

converter is limited for step down applications [12-13].

Bridgeless SEPIC converter has large number of

semiconductor devices in the current conduction path during

each switching cycle and has discontinuous output current resulting in a relatively high output ripple.Bridgeless buck-

boost converter operates with high peak current in power

components and poor transient response that makes it less

efficient [15-16].

This paper presents a BL Cuk converter-fed BLDC

motor drive with constant dc link voltage of VSI for

improved power quality at ac mains with reduced

components. Section II deals with Cuk derived converter

topologies, Section III deals with simulation analysis of the

proposed method with PID Controller, Section IV deals with

simulation analysis of the proposed method with FLC,

Section VI deals with conclusion and future scope of the paper.

CUK DERIVED CONVERTER TOPOLOGIES

Bridgeless Cuk converter has the following advantages

because of its features:

1. Easy implementation of transformer isolation.

2. Natural protection against inrush current occurring

at start up or overload current, lower input current

ripple.

3. Less electromagnetic interference associated with

discontinuous conduction mode (DCM) topology.

4. Cuk converter has both input and output currents with a low current ripple.

5. Can achieve power factor near to the unity.

For applications, which require a low current ripple at

the input and output ports of the converter, the Cuk

converter seems to be a potential candidate in the basic

converter topologies.

The three new Cuk derived topologies are derived

from the conventional PFC Cuk rectifiers [17-19]. The

bridgeless Cuk derived converter is a combination of two

dc-dc converters. One for each half line period (T/2) of the

input voltage. There are one or two semiconductor switches

in the current flowing path. Current stresses in the active and passive switches are further reduced. Circuit efficiency is

improved as compared to conventional Cuk rectifier. They

do not suffer from high common mode noise problem and

common mode emission performance is similar to the

conventional PFC topologies. . Power Factor Correction

rectifiers are used to improve the rectifier power density and

to reduce noise emissions via soft switching techniques or

coupled magnetic topologies [7-9].




(a) Type I

(b) Type II

(c) TypeIII

Figure 1. CUK Derived Converter Topologies

The three new Cuk rectifiers are compared based on

components count, mode of operation in DCM and driver circuit complexity as tabulated in Table 1. The bridgeless

PFC Cuk rectifiers of Fig. 1 utilize two power switches (Q1

and Q2). However, the two power switches can be driven by

the same control signal, which significantly simplifies the

control circuitry.

TABLE I. CUK CONVERTERTOPOLOGIES IN DCM

MODE

Item Conv.

Cuk

Type-I Type-

II

Type-

III

Diode 4 slow+1

fast

2

slow+3

fast

2 fast 2

slow+2

fast

Switch

1 2(with

unidirec

tional

current

capabili

ties)

2 2

Current

Conducti

on Path

when SW

on

2 slow

diodes

and 1

switch

1 slow

diode

and 1

switch

with

series

diode

1 body

diode

and 1

switch

1

slow

diode

and 1

switch

Current

Conducti

on Path

when SW

on

3 diodes

( 2 slow

and 1 fast)

2 diodes

( 1 slow

and 1 fast)

1 fast

diode

2

diodes(

1 slow and 1

fast)

Current

Conducti

on Path

in DCM

2 slow

diodes

1 slow

diode

- 1 slow

diode

Compone

nt Count

10 11 11 13

Number

of

Capacito

rs

2 3 4 3

Driver

circuit

Complexi

ty

1 non-

floating

2 non-

floating

1

floatin

g + 1

non-floatin

g

2

non-

floatin

g

Operation of bl cuk converters

The choice of mode of operation of a PFC converter is a

critical issue because it directly affects the cost and rating of

the components used in the PFC converter [20] - [22].

Continuous Conduction Mode (CCM) and Discontinuous

Conduction Mode (DCM) are widely used in practice. In

CCM or DCM, the inductor‟s current or the voltage across

intermediate capacitor in a PFC converter remains

continuous or discontinuous in a switching period

respectively. To operate a PFC converter in CCM, one requires three sensors (two voltage, one current) while a

DCM operation can be achieved using a single voltage

sensor. The stresses on PFC converter switch operating in

DCM are comparatively higher as compared with its

operation in CCM.By operating the rectifier in DCM,

several advantages can be gained such as:

1. Natural near-unity power factor.

2. The power switches are turned ON at zero current

and the output diodes are turned OFF at zero

current.

(a)




(b)

Figure 2. Circuits of Type I Cuk rectifier (a)During positive half cycle.

(b)During negative half cycle.

The mode of operation is an application dependent.

CCM is suitable for high power applications and DCM for

low power applications. Thus, the losses due to the turn-on

switching and the reverse recovery of the output diodes are

considerably reduced. Conversely, DCM operation

significantly increases the conduction losses due to the

increased current stress through circuit components. As a

result, this leads to one disadvantage of the DCM operation, which limits its use to low-power applications (less than 300

W). Hence, DCM is preferred for low-power applications.

(a)

(b)

Figure 3. Circuits of Type II Cuk rectifier

(a)During positive half cycle.


(a)

(b)

Figure 4. Circuits of Type III Cuk rectifier

(a)During positive half cycle.


IV. SIMULATION OF CUK CONVERTER FED

BLDC MOTOR DRIVE USING PID CONTROLLER

A computer simulation model for PFC Cuk converter

fed BLDC motor drive is developed using the

MATLAB/SIMULINK software is shown in figure. 5. The

switching pulse for Cuk converter is generated with the

help of PID controller. Single phase ac voltage is given as

input to the Cuk rectifier. The voltage source inverter boost

the DC voltage of the rectifier and is fed to the BLDC

Motor.




Figure 5. Simulink Model Using PID Controller

The speed control can be achieved by varying the DC

link voltage of the inverter. The power factor calculation

block is shown in figure 6.

Figure 6. Power Factor Calculation Block

The power factor of AC mains is 0.88, which is not

good. Hence the power quality gets affected.

Figure 7. Sub Block for Power Factor Calculation

The sub block of power factor calculation is shown in

figure 7.The line side voltage and current is taken as input and it is converted into corresponding real and reactive

power and the power factor is calculated with the help of

math operator blocks.

Figure 8. Speed Response

The speed response of the BLDC motor is shown in

figure 8. Depending upon the loading condition, the PID

controller controls the DC link voltage to obtain the

constant speed response. Initially the speed is gradually

increased and settled to reference value.

Figure 9. Electromagnetic Torque with PID Controller

The electromagnetic torque waveform is shown in

figure 9. It contains more amount of ripple content in its

waveform which degrade the performance of the motor. At the time of starting the acceleration of the motor is high

because of high starting torque.

Figure 10. Stator Back EMF with PID Controller

The trapezoidal shape back EMF waveform was

shown in figure 10. The back EMF waveform is departed from its ideal shape at the time of starting. Later then it

regains its original form.

V. SIMULATION OF CUK CONVERTER FED

BLDC MOTOR DRIVE USING PID

CONTROLLER

A computer simulation model for PFC Cuk converter fed

BLDC motor drive is developed using the

MATLAB/SIMULINK software is shown in figure 11. The

switching pulse for Cuk converter is generated with the

help of hall signals obtained from hall sensors. The speed of

the motor is controlled by controlling the DC link voltage of the inverter with the help of fuzzy logic controller.

Single phase ac voltage is given as input to the Cuk

rectifier. The voltage source inverter boost the DC voltage

of the rectifier and is fed to the BLDC Motor.

Figure 11. Simulink block of BLDC motor drive with

Fuzzy logic controller

The simulation block for AC mains power factor

calculation block is shown in figure 12. The display shows the AC mains power factor which could be affected when

the motor is connected to the mains. With the help of cuk

converter with fuzzy logic switching pulse, the power factor

has been improved to 0.98 which is nearer to unity.

Figure 12. Power Factor Calculation Block

The sub block of power factor calculation is shown in

figure 13.The line side voltage and current is taken as input and it is converted into corresponding real and reactive

power using real and reactive power Simulink




block.

Figure 13. Sub block for power factor calculation

The two inputs are taken as speed error and change in

speed error for fuzzy logic controller. Thus the decision

making rules for FLC for obtaining controlled signal

comprises of 11x3 matrices. Based upon these rules the

switching pulse for cuk converter is generated corresponding to speed variation. The cuk converter

regulates the supply given to the inverter, so that the speed

should be maintained at the reference value.

TABLE II. RULES TABLE FOR FLC

As said earlier compared to other bridgeless converters,

the type III cuk converter effectively regulates the inverter

supply and improves the power factor at AC mains near to unity. The ac-dc bridgeless converter thus reduces the

conduction losses and the use of PWM inverter makes it

possible to operate at the fundamental switching frequency.

The artificial intelligent fuzzy logic controller generates the

switching pulses for the Cuk converter.

The speed is controlled effectively by controlling the

DC link voltage. For the performance evaluation of the

proposed drive under input ac voltage variation, the DC link

voltage is kept constant as shown in figure 14.

Figure 14. Speed Response

The speed should be linearly varied and settled at

0.07ms. Compared to other controllers, the settling time of

the artificial intelligent controllers is minimum.

The electromagnetic torque waveform is shown in figure

15. At a time of starting, the torque should be maximum and

reduced to nominal value after the motor settled to reference

speed.

Figure 15. Electromagnetic Torque waveform

Due to commutation of inverter, the generated

electromagnetic torque contains significant amount of ripple

in its waveform. This causes acoustic noise in the motor and

performance of the motor gets degraded.

Figure 16. Back EMF Waveform

The trapezoidal shape back EMF waveform is shown in

figure 16. The shape of the back EMF waveform gets collapsed at the time of starting. After the motor settles to

the reference value, the non-linearity in the back EMF

waveform gets reduced.

Figure 17. Total Harmonic Distortion

The Total Harmonic Distortion (THD) is achieved as

5.46% is represented in figure 17. For any type of load the harmonic level is almost constant.

VI. CONCLUSION

A comparative analysis of different types of converter

topologies for power factor correction in BLDC motors has

been discussed. A suitable Type III Cuk Converter seems to

be a potential candidate for PFC.The bridgeless Cuk




converter fed BLDC motor drive improves the power factor

at the AC mains near to the unity with precise speed control

of fuzzy logic controller with low THD. The suitable

controller for PFC operation of BLDC motor drives has

been analysed. FLC seems to be the best controller in

performance improvement of BLDC motor drives for

attaining the power factor near to unity.Hence the overall

system can be implemented in Air-conditioning System.In the future work, renewable energy like Solar, Fuel cell can

be used as the source for the system which is useful to

reduce the demand of electricity. It also reduces the

pollution and greenhouse effect. Controller performance

may further improved by using other intelligent control

algorithms like genetic-fuzzy and neuro-genetic. As far as

the environment aspects are concerned, this kind of hybrid

systems have to be wide spread in order to cover the energy

demands and in the way to help reduce the greenhouse gases

and the pollution of the environment.

References [1] Gieras JF, Wing (2002). M.: Permanent magnet motor

technology – design and application. Marcel Dekker

Inc., New York

[2] Handershot JR., Miller (2010). T.J.E.: Design of

brushless permanent magnet motors. Clarendon Press,

Oxford, 2010.

[3] Hanselman (2003) D.C.: Brushless permanent magnet

motor design. McGraw-Hill, New York.

[4] Krishnan R (2001).: Electric motor drives: modeling,

analysis and control. Pearson Education, India.

[5] Toliyat (2004). H.A.: Campbell S.: DSP-based electromechanical motion control. CRC Press, New

York.

[6] Limits for Harmonic Current Emissions (Equipment

Input Current ≤16 A per Phase) (2000) Int. Std. IEC

61000-3-2.

[7] Choi W, Kwon J, Kim E, Lee J, and Kwon B (2007).

Bridgeless boost rectifier with low conduction losses

and reduced diode reverse-recovery problems. IEEE

Trans. Ind. Electron., 54 (2), 769–780.

[8] Jang Y and Jovanovi´c MM (2011). Bridgeless high-

power-factor buck converter. IEEE Trans. Power

Electron. 26 (2), 602–611. [9] Moschopoulos G and Kain P (2004). A novel single-

phase soft-switched rectifier with unity power factor

and minimal component count. IEEE Trans.Ind.

Electron. 51 (3), 566–575.

[10] Huber L, Jang Y and Jovanovic M (2008). Performance

evaluation of bridgeless PFC boost rectifiers. IEEE

Trans. Power Electron. 23(3), 1381–1390.

[11] Ye H, Yang Z, Dai J, Yan C, Xin X, and Ying J (2004).

Common mode noise modeling and analysis of dual

boost PFC circuit. In Proc. Int. Telecommun. Energy

Conf, 575–582. [12] Fardoun, Ismail EH, Al-Saffar MA, and Sabzali AJ

(2012) New „real‟ bridgeless high efficiency ac-dc

converter. In Proc. 27th Annu. IEEE APEC Expo. 5(9),

317–323.

[13] Jang Y and Jovanovi´c MM (2011) Bridgeless high-

power-factor buck converter. IEEE Trans. Power

Electron. 26(2):602–611.

[14] Wei W, Hongpeng L, Shigong J, and Dianguo X

(2008). A novel bridgeless buck-boost PFC converter.

In Proc. IEEE Power Electron. Spec. Conf., 1304–

1308.

[15] Vashist Bist, Bhim Singh (2014). An Adjustable-Speed

PFC Bridgeless Buck–Boost Converter-Fed BLDC

Motor Drive. IEEE Transactions on Industrial

Electronics, 61(6), 2665-2677.

[16] Abbas A. Fardoun (2012). New Efficient Bridgeless

Cuk Rectifiers for PFC Applications. IEEE Trans. on Power Electronics, 27(7), 3292-3300.

[17] Fardoun, Ismail EH, Sabzali AJ, and Al-Saffar MA

(2010). A comparison between three proposed

bridgeless Cuk rectifiers and conventional topology for

power factor correction. In Proc. IEEE ICSET, 6(9), 1–

6.

[18] Mahdavi M and Farzaneh-Fard H (2012). Bridgeless

CUK power factor correction rectifier with reduced

conduction losses. IET Power Electron. 5(9), 1733–

1740.

[19] Singh B, Singh BN, Chandra A, Al-Haddad K, Pandey

A, and Kothari DP (2003). A review of single-phase improved power quality ac-dc converters. IEEE Trans.

Ind. Electron. 50(5), 962–981.

[20] Singh B, Singh S, Chandra A, and Al-Haddad K (2011).

Comprehensive study of single-phase ac-dc power

factor corrected converters with high-frequency

isolation. IEEE Trans. Ind. Informat., 7(4),540–556

[21] Younghoon Cho (2014). A Low Cost Single-Switch

Bridgeless Boost PFC Converter, International Journal

of Power Electronics and Drive System (IJPEDS), 4(2),

256-264.

[22] Lenine D, Ch.Sai Babu, Shankaraiah G (2012). Performance Evaluation of Fuzzy and PI Controller for

Boost Converter with Active PFC. International

Journal of Power Electronics and Drive System

(IJPEDS), 2(4), 445-453.

[23] Lei Jin-Ii. Adaptive Control for Brushless DC Motor

Based on Fuzzy Inference. TELKOMNIKA Indonesian

Journal of Electrical Engineering. 2014; 12(5): 3392-

3398.

[24] Yueshan Wang, Liwan Chen, Zenghan Chen. A Fuzzy

Self-tuning Controlled Feeding Servo System of

Machine Tool. TELKOMNIKA. 2013; 11(5): 2351-

2358. [25] PearlyCatherine. J and Balamurugan. R, “An Approach

of Power Factor Correction in BLDC Motor Drives

Using Cuk Derived Converters” TELKOMNIKA

Indonesian Journal of Electrical Engineering, vol. 12,

Issue 12, pp.8092-8097, December 2014.

bridgeless pfc cuk derived converter fed bldc motor · pdf filecuk derived converter ... boost...

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