Brushless dc (BLDC) motors are very popular and are
replacing brush motors in numerous applications due to its superior electrical
and mechanical characteristics owing to its trouble free construction. This
paper presents the BLDC motor sensorless speed control system with fuzzy logic
implementation. The sensorless techniques based on the back EMF sensing and the
rotor position detection with a high starting torque is suggested. The rotor
position is aligned at standstill for without an additional sensor. Also, the
stator current can be easily adjusted by modulating the pulse width of the
switching devices during alignment which will be helpful to reduce cost and
complexity of the drive system without compromising the performance. The design
analysis and simulation of the proposed system is done using MATLAB version
2010a and the simulation results of sensored drive using PI controller and
sensorless drive using proposed methods are analyzed.
KEYWORDS:
1.
Brushless dc motor
2.
Hall sensored
drive
3.
PI controller
4.
Back EMF sensorless drive
5.
Fuzzy controller
SOFTWARE: MATLAB/SIMULINK
BLOCK
DIAGRAM:
Fig. 1.Proposed block diagram of
sensorless speed control of BLDC motor.
EXPECTED SIMULATION RESULTS:
Fig. 2(a) Variation of
Back EMF signal with reference set at 1400 rpm
Fig. 2(b) Variation of
stator current with reference set at 1400 rpm.
Fig. 3.Generated pulse from fuzzy
logic controller.
Fig. 4(a) Speed
response of sensored drive technique using PI controller.
Fig. 4(b) Speed
response of sensorless drive technique using PI controller.
Fig. 4(c) Speed
response of sensorless drive technique using fuzzy logic controller.
Fig. 5(a) Variation of
Electromagnetic torque with reference set at 1400 rpm under sensorless drive
using PI controller.
Fig. 5(b) Variation of
Electromagnetic torque with reference set at 1400rpm under sensorless drive
using fuzzy logic controller.
CONCLUSION
Sensorless speed control of BLDC motor
drive with fuzzy logic implementation based on comparator with zero crossing
detection have been experimented using MATLAB and evaluation of results are
observed. The simulation results have shown that speed response of the BLDC
motor can be controlled without sensors and also reduces the torque ripple. The
results obtained from sensorless speed control of BLDC motor demonstrates that
the system is less cost compared to sensored control and also good dynamic
performance is obtained. This makes the motor suitable in application such as
fuel pump, robotics and industrial automation. The proposed speed control
scheme is robust, efficient and easy to implement in place of sensored
applications.
REFERENCES
.
[1]
Nobuyuki Matsui, “Sensorless PM Brushless DC
Motor Drives”, IEEE Trans. on
Industrial Electronics, Vol.43, No.2,pp.300-308, April 1996.
[2]
Champa.P,
Somasiri.P, Wipauramonton.P and Nakmahachalasint.P, “Initial Rotor Position
Estimation for Sensorless Brushless DC Drives”, IEEE Trans. on Ind. Applications, Vol.45,No.4, pp.1318-1324,July
2009.
[3]
Somanatham.R, Prasad.P.V.N, Rajkumar.A.D,
“Modelling and Simulation of Sensorless Control of PMBLDC Motor Using
Zero-Crossing Back EMF Detection” IEEE
SPEEDAM 2006 International Symposium on Power Electronics, Drives, Automotive
and Motion.
[4]
Bimal K Bose, “Modern Power Electronics and AC
Drives”, Pearson Education Asia 2002.
[5]
Miller.
T.J.E., “Brushless permanent magnet and reluctance motor drives ", Clarendon Press, Oxford, 1989.
