ISSN 2319-8885
Vol.05,Issue.04,
February-2016,
Pages:0659-0666 www.ijsetr.com
C H .
M ICHAEL A NAND
1 2
, J.
A LLA B AGASH
1
PG Scholar, Dept of EEE, Malineni Lakshmaiah Engineering College, Kanumalla, Singarayakonda, Prakasam(Dt), AP, India.
2
Assoc Prof, Dept of EEE, Malineni Lakshmaiah Engineering College, Kanumalla, Singarayakonda, Prakasam(Dt), AP, India.
Abstract: This paper presents an analysis by which the dynamic performances of a permanent magnet brushless dc (PMBLDC) motor drive with different speed controllers can be successfully predicted. The control structure of the proposed drive system is described. The dynamics of the drive system with a classical proportional-integral (PI) and a Fuzzy-Logic (FL) speed controllers are presented.
This drive system has advantages like reduced total harmonic distortion and higher torques. PI, Fuzzy logic controllers are discussed. Closed loop simulation response is obtained for PI, Fuzzy and Hybrid controller with a disturbance in the input source. The conventional circuit is improved by introducing fuzzy Controller. In Industrial application the physical integration of fuzzy controller in the motor body itself is able to make them most suitable for low power (0.5hp) blowers and low power (50W) tube axial fans for cooling the electronic equipment. The performance of the PMBLDCM system is simulated and implemented. Simulation results of these systems are presented and the performance measures are compared.
Keywords: Bidirectional AC-DC Converter, PMBLDCM Drive, Power Quality (PO), VSI, Fuzzy Logic Controller.
I. INTRODUCTION
With the rapid development of microelectronics and power switches, most adjustable-speed drives are now realized with ac machines. Permanent Magnet Synchronous Motor
(PMSM) with sinusoidal shape back-EMF and brushless DC
(BLDC) motor with trapezoidal shape back-EMF drives have been extensively used in many applications, ranging from servo to traction drives due to several distinct advantages such as high power density, high efficiency, large torque to inertia ratio, and better controllability. Brushless DC motor (BLDC) fed by two-phase conductionscheme has higher power/weight, torque/current ratios and it is less expensive due to the concentrated windings which shorten the end windings compared to three-phase permanent magnet synchronous motor (PMSM) [1]-[2]. There are two methods of controlling
PMBLDC motor namely sensor control and sensor less control. The latter has advantages like cost reduction, reliability, elimination of difficulty in maintaining the sensor etc. Sensor less control is highly advantageous when the motor is operated in dusty or oily environment, where cleaning and maintaining of Hall Sensors is required for proper sensing of rotor position. Sensor less method is preferred when the motor is in less accessible location.
Accommodation of position sensor in motor used in compact unit such as computer hard disk may not be possible. Novel direct back emf detection for sensor less BLDC motor is given in [3]. This paper demonstrates a sensor less technique to drive a three phase brushless DC motor with a multi level voltage Inverter system using voltage control method with
Fuzzy logic control. PMBLDC motors drives are used in a wide range of commercial and residential applications such as domestic. Conventionally, PI, PD and PID controller are most popular controllers and widely used in most power electronic closed loop appliances however recently there are many researchers reported successfully adopted Fuzzy Logic
Controller (FLC) to become one of intelligent controllers to their appliances [4-6]. With respect to their successful methodology implementation, control closed loop forward buck converter.
This kind of methodology implemented in this paper is using fuzzy logic controller with feed back by introduction of voltage output respectively. The introduction of voltage output in the circuit will be fed to fuzzy controller to give appropriate measure on steady state signal. The fuzzy logic controller serves as intelligent controller for this propose. This paper deals with the detailed modeling, design and performance evaluation of the proposed drive with conventional PI controller and intelligence controller (FLC) and simulation work is carried out in MATLAB/SIMULINK platform. Novel direct back emf detection for sensor less
BLDC motor is given in [7]. This paper demonstrates a sensor less technique to drive a three phase brushless DC motor with a multi level voltage Inverter system using voltage control method with Fuzzy logic control. PMBLDC motors drives are used in a wide range of commercial and residential applications such as domestic. Many machine design and control schemes have been developed to improve the performance of BLDC motor drives. The model of motor drives has to be known in order to implement an effective control in simulation. Some simulation models based on state space equations, Fourier series, d-q axis model, and variable
Copyright @ 2016 IJSETR. All rights reserved.

C H .
M ICHAEL A NAND , J.
A LLA B AGASH sampling have been proposed for the analysis of BLDC motor drives [8-11]. Furthermore, fuzzy logic controllers (FLCs) are used to analyze BLDC motor drives in literature [12, 13].
(4)
Where m is modulation index, and it is considered I. V dc
is the reference DC link voltage (400V). The fundamental rms voltage at VSC terminals obtained as 282.88 V using Eq. (4).
The relation between fundamental voltages at VSC terminals is given as,
II. SYSTEM CONFIGURATION AND PRINCIPLE OF
OPERATION
Fig.1.shows the system configuration of a proposed
PMBLDCM drive. It consists of a bidirectional single-phase full bridge VSC and a three-phase VSI with a common DC link feeding to a PMBLDCM. A bidirectional single-phase
VSC consists of two half bridges with insulated gate bipolar transistors (IGBTs). An inductor is used between single phase
AC supply and a bidirectional V sc
. A bidirectional VSC controls to draw sinusoidal current in phase with input supply voltage along with regulating DC link voltage. The proposed drive is suitable to operate in all four quadrants. The singlephase VSC operates as a rectifier in forward and reverse motoring mode, while three-phase VSI operates as an electronic commutator during this mode. During regenerative braking, single-phase VSC operates as an inverter and three phases VSI performs as a rectifier.
(5)
Where Vs is rms value of input supply voltage which is taken as 220 V and Is is rms value of supply current as,
(6)
Therefore, interface inductor is obtained using Eq. (5) is 17 mH.
III. DESIGN OF PMBLDCMDRIVE
The design of an improved power quality 2 kW PMBLDCM drive consists of selection of interface inductors, intermediate
DC link capacitors and switching devices for a VSC and a
VST.
A. Selection of DC Link Voltage and Intermediate DC link
Capacitor
The VSC is supplied by a single-phase 220 V AC supply.
The selection of minimum DC link voltage depends on amplitude of AC voltage and desired rated DC link voltage of a PMBLDCM. It must be greater than or equal to the peak value of supply voltage and equal to desired rated DC link voltage of the PMBLDCM.
(1)
Where V m
is peak value of single-phase supply voltage and
V rated
is desired rated DC link voltage of a power of the
PMBLDCM.
A 400V DC link is selected and for maintaining the constant
DC link voltage, an intermediate DC link capacitor is used.
The selection of a DC link capacitor is given as
Where I de is the DC link current which is obtained as,
(2)
(3) w is the angular frequency (2nt) in rad/s and V deripple
is the I % of rated DC link voltage. The DC link capacitor is obtained as
1900 µF, using Eq. (2).
B. Selection of Interface Inductor
An interface inductor is used between AC supply and AC terminals of a single-phase VSC. The inductor is used to absorb PWM voltages. The fundamental rms voltage V c
at
VSC terminal is given as,
Fig.1.Control Scheme for Bidirectional AC-DC Converter
Fed PMBLDCM Drive.
C. Design of Voltage Source converter (VSC)
The voltage source converter (VSC) is designed on the basis of apparent power through the VSC. The rms current through each leg of VSC is obtained 9.09A using Eq. (6). Where P in the input power at VSC terminals. The maximum current through IGBTs is calculated as,
(7)
Considered 10 % peak-peak ripple current, the maximum current through IGBT is obtained 17 Amp. Therefore 25A,
600V IGBT's are used for the V
Sc
.
D. Design of Voltage Source Inverter (VSI)
The VSI consists of six IGBTs switches. The selection of
IGBTs is based on rated current of a PMBLDCM. The stall current of PMBLDCM is 8.45A, as obtained from manufacturer data sheet and maximum current through IGBT in each phase is obtained as,
(8)
Considered 10% peak-peak ripple in stall current, maximum current through IGBTs is obtained as 15A. Therefore 15A,
600V IGBT's are selected for a three-phase VSI.
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666

Fuzzy Based Multilevel Inverter Fed PMBLDC Motor Drive for Optimal Power Quality of the Converter
IV. CONTROL ALGORITHMS
A. Control Algorithm for Bidirectional AC-DC Converter
The control algorithm for bidirectional AC-DC converter is based to regulate DC link voltage under change in loading condition. Equations used in mathematical modeling are as
Regulated DC link voltage: The reference DC link voltage
(V de
*) is compared with the sensed DC link voltage (V at the k th
instant of time, V de de
). If,
*(k) is the reference DC link voltage and V de
(k) is the voltage sensed at the DC link, then the voltage error V e
(k) is given as with sensed currents (Ta, hand Te) of PMBLDCM and error is given to the PWM current controller which generates switching pulses for a VSI.
V. METHMATTCAL MODELLING OF VSI FED
PMBLDCM DRIVE
A. Voltage Source inverter (VSI)
Fig.2.shows an equivalent circuit of a VST-fed PMBLDCM.
The output of a VST to be fed to phase 'a' of the PMBLDC motor is given
(12)
(13)
(9)
The voltage error V e
(k) is fed to a proportional-integral (PI) controller. The output of a PI controller is given as,
(10)
Where Kp and Ki are the proportional and integral gain constants of the PI controller.
(14)
(15)
Where 1 and 0 represents the 'on' and 'off position of the
IGBT of the VST, respectively and are considered in a similar way for other IGBTs. The voltages V bo
, V co
, V bn
and V cn
are generated in similar manner for two other phases of the VST feeding PMBLDCM. The voltages V ao
, V bo
, V co
and V no
are voltages of the three-phase and the neutral point (n) with respect to the virtual mid-point of the DC link voltage.
Estimation of Reference VSC Current: The reference current for the control of a VSC is obtained as, TABLE I: Resolver Input and Output Signals
(11)
Where U vs
is the unit template of the voltage at input AC mains. It is generated by introducing a gain with input AC supply voltage.
PWM Controller: For the control of a VSC, an unipolar switching scheme is employed. Leg A and B of the full-bridge converter are controlled separately by comparing carrier signal with reference signals. The reference input current of
PWM rectifier Is* is compared with sensed current (Is) to generate the current error ∆I *= (Is*- Is). This current error is compared with fixed frequency triangular signal md (t) to get the switching signal for the lGBT's of leg A. When current error
(12)
For the switching of TGBT's of leg 'B' the current error
M* is multiplied by unit negative gain and compared with triangular waveform md (t).
B. Control Algorithm for VSI
(13)
The VST is used as an electronic commutator. The reference speed (w/) is compared with sensed speed (w,) . The speed error (we) is fed to the speed PT controller. The output of speed PT controller is multiplied with resolver output, to generate estimated reference current (T:, h* and Te*) as shown in Table T. These reference currents are compared
Fig.2.Equivalent Circuit of a VSI Fed PMBLDCM Drive.
VI. PMBLDC MOTOR
For a three phase star connected PMBLDC motor, per phase voltages (V an
, V bn
and V cn
) are given as,
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666

C H .
M ICHAEL A NAND , J.
A LLA B AGASH
(16)
Where i an
, i bn
and i cn
are phase currents, e an
, e bn
and e cn are per phase back emfs, Rs is the per phase resistance, L and M are the self and mutual inductance of the stator's winding respectively and p is the differential operator. For a three phase star connected PMBLDC motor
(17) methods. Fuzzy set theory has been widely used in the control area with some application to power system [5]. A simple fuzzy logic control is built up by a group of rules based on the human knowledge of system behavior. Matlab/Simulink simulation model is built to study the dynamic behavior of converter as shown in Fig.3. Furthermore, design of fuzzy logic controller can provide desirable both small signal and large signal dynamic performance at same time, which is not possible with linear control technique. Thus, fuzzy logic controller has been potential ability to improve the robustness of compensator.
Substituting Eq. (17) in Eq. (16), we get
(18)
Using Eq. (18), the current derivative are obtained as,
The electromagnetic torque Te is given as,
(19)
(20)
Where w, represents the rotor speed, x represent the phase a, b or c and n represent the neutral terminal. This expression faces computational difficulty at zero speed, hence to overcome this, e xn
is defined as,
(21)
Where Ax represents the flux linkage and function fxn(θ) have the same shape as of the back emf. Substitute Eq. (21) in
Eq. (20) as,
The torque balance equation is given as,
(22)
(23)
Where T
L
is load torque, J is the moment of inertia of the motor and B is the frictional constant. Using Eq. (20), the speed derivative is expressed
(24)
And last the neutral voltage V no
with respect to point '0' as shown in Fig.2. is given as,
(25)
Eq. (16) - (25) represents the dynamic model of PMBLDCM.
VII. FUZZY LOGIC CONTROL
L. A. Zadeh presented the first paper on fuzzy set theory in
1965. Since then, a new language was developed to describe the fuzzy properties of reality, which are very difficult and sometime even impossible to be described using conventional
Fig.3.Fuzzy Logic Control Scheme for Bidirectional AC-
DC Converter Fed PMBLDCM Drive.
The basic scheme of a fuzzy logic controller is shown in
Fig 4 and consists of four principal components such as: a fuzzy fication interface, which converts input data into suitable linguistic values; a knowledge base, which consists of a data base with the necessary linguistic definitions and the control rule set; a decision-making logic which, simulating a human decision process, infer the fuzzy control action from the knowledge of the control rules and linguistic variable definitions; a de-fuzzification interface which yields non fuzzy control action from an inferred fuzzy control action
[10].
Fig.4. Block diagram of the Fuzzy Logic Controller (FLC) for proposed converter.
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666

Fuzzy Based Multilevel Inverter Fed PMBLDC Motor Drive for Optimal Power Quality of the Converter
Fig.5. Membership functions for Input, Change in input,
Output.
Rule Base: the elements of this rule base table are determined based on the theory that in the transient state, large errors need coarse control, which requires coarse in-put/output variables; in the steady state, small errors need fine control, which requires fine input/output variables as shown in Fig.5.
Based on this the elements of the rule table are obtained as shown in Table 1, with ‘V dc
’ and ‘V dc-ref’ as inputs.
TABLE I: Rule Table
Fig.7.Simulation Model Of By Using PI Controller.
VIII. MATLAB/SIMULINK RESULTS
Simulation results of this paper is as shown in bellow
Figs.6 to 18.
Fig.6.Matlab/Simulink Model of Bidirectional AC-DC
Converter Fed PMBLDCM Drive.
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666
Fig.8.Starting performance of the PMBLDCM.
The performance of proposed PMBLDCM drive under starting is shown in Fig.8. The PMBLDCM drive is supplied from a single-phase 220 V AC supply with rated load torque at shaft. The performance is obtained in terms of AC supply

C H .
M ICHAEL A NAND , J.
A LLA B AGASH voltage (V s
), supply current (I s
), DC link voltage (V dc
), stator currents of PMBLDCM (T a
, I b
and l e
), motor speed (Ns ) and torque (Te). At 0.1s, the starting command is released and it is found that motor achieves reference speed in very less time.
However, a high starting current is observed which may be controlled by ramp starting. T t
is observed that DC link voltage is maintained constant reasonably even at starting conditions. The current waveform of AC supply is in phase with the supply voltage during these conditions. Fig.9. shows the performance of improved power quality PMBLDCM drive under change in reference speed. Till 0.4 s, the
PMBLDCM is running at 500 rpm with steady state conditions achieved. At O.4s, there is a change in reference speed to 1000 rpm and it is found that PMBLDCM achieves desired reference speed. However, a change in supply current
(Is) magnitude and PMBLDCM current (T a
, I b
and l e
) are recorded in order to meet new load conditions. The DC link voltage is maintained constant under these conditions. The power quality parameters at supply side under wide change in reference speed are obtained and shown in Table TT. T t
is observed that the performance is satisfactorily under wide speed control. The THD and harmonic spectra of AC supply current drawn by the proposed drive under change in speed from 500 to 1000 rpm as shown in Fig.11. The THD of supply current is 4.62 %, which is within IEEE 519-1992 acceptable limit.
Fig.10.AC mains current and its harmonic spectrum of speed changes.
Fig.9. PMBLDCM drive under speed variation from 500 to 1000 rpm.
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666
Fig.11.PMBLDCM drive under change in the rated torque.

Fuzzy Based Multilevel Inverter Fed PMBLDC Motor Drive for Optimal Power Quality of the Converter
Fig.11.shows the performance of improved power quality under change in load torque. Till 0.6s, PMBLDCM run at
1000 rpm. At 0.6s, torque is change from rated value to half the rated value. The DC link voltage is maintained under this condition but input and output power of PMBLDCM drive will be decrease under this condition. Supply current of
PMBLDCM and single-phase current is also decrease because power will be decrease.
Fig.15.currents(ia,ib,ic) in PMBLDC motor.
Fig.12.AC mains current and its harmonic spectrum of change in the rated torque.
Fig.16.input power and dc-link voltage.
Fig.13.Simulation Model of byusing fuzzy logic Controller.
Fig.17.Speed and Torque of PMBLDC Motor Drive.
Fig.18.THD for source current by using Fuzzy logic controller. Fig.14.source voltage and source current.
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666

C H .
M ICHAEL A NAND , J.
A LLA B AGASH
IX. CONCLUSION
A single stage PFC control strategy of a VSI fed PMBLDCM drive using forward buck converter using conventional PI controller and fuzzy logic controller has been validated for a compressor load of an air conditioner. The current multiplier approach with average current control has been used for operation of a forward buck converter in continuous conduction mode. The PFC forward buck converter of the proposed drive has ensured nearly unity PF in wide range of the speed and the input AC voltage. Moreover, power quality parameters of the proposed drive are in conformity to the
International standard IEC.
X. REFERENCES
[1]T.Kenjo and S. Nagamori, Permanent Magnet Brushless
DC Motors. Oxford, U. K.: Clarendon, 1985.
[2]T. J. Sokira and W. Jaffe, Brushless DC Motors: Electronic
Commutation and Control. New York: Tab, 1989.
[3]J. R. Hendershort Jr and T.J.E. Miller, Design of Brushless
Permanent-Magnet Motors, Clarendon Press, Oxford, 1994.
[4]J. F. Gieras and M. Wing, Permanent Magnet Motor
Technology- Design and Application, Marcel Dekker.
[5] P. Pillay and R. Krishnan, "Modelling, simulation and analysis of a permanent magnet brushless dc motor drives, part TT: the brushless dc motor drive", IEEE Trans. Ind App., vo!. 25, no. 2, pp. 274-279, Mar.1Apr. 1989.
[6] Sam-Young Kim, Chinchul Choi and Kyeongjin Lee, "An
Improved rotor Position Estimation with Vector-Tracking
Observer in PMSM Drives with Low-resolution Hall-Effect sensors", IEEE Trans. Ind App., vo!. 58, no. 9, pp. 4078-
4086, September2011.
[7] Bhim Singh and Vashist Bist, "Reduced Sensor Based
Improve Power Quality CSC Converter fed BLDC Motor
Drive", 2012 IEEE International Corif. Power Electronic,
Drives and Energy Systems, Bengaluru dEc. 2012, pp. 16-19.
[8] S. Cuk and R. D. Middlebrook, "Advances in switched- mode power conversion Part-I", IEEE Trans. Ind Electron., vo!. lE-30, no. 1, pp. 10-19, Feb. 1983.
[9] C. J. Tseng and C. L. Chen, "A novel ZVT PWM Cuk power factor corrector", IEEE Trans. Ind Electron. , vo!. 46, no. 4, pp. 780-787, Aug. 1999.
[10] N. Mohan, M. Undeland, and W. P. Robbins, Power
Electronics: Converters, Applications and Design. Hoboken,
NJ: Wilkey, 1995.
[11] Bhim Singh, Sanjeev Singh, Ambrish Chandra, and
Kamal AI-Haddad, "Comprehensive Study of Single-Phase
AC-DC Power Factor Corrected Converters With High-
Frequency Isolation", IEEE Trans. Ind Iriformatics, vo!. 7, no.
4, pp. 540-555, November 2011.
[12] Sanjeev Singh and Bhim Singh, "PFC Bridge Converter for Voltage-controlled Adjustable-speed controlled
PMBLDCM Drive", Journal of Electrical Engineering and
Technology, vo!. 6, no. 2, pp. 215- 225, 2011.
[13] Sanjeev Singh and Bhim Singh, "A voltage controlled
PFC Cuk Converter-Based PMBLDCM Drive for Air-
Conditioners", IEEE Trans. Ind App., vo!. 48, no. 2, pp. 832-
838, March/April 2012.
International Journal of Scientific Engineering and Technology Research
Volume.05, IssueNo.04, February-2016, Pages: 0659-0666