ABSTRACT:
Modeling
and simulation of electromechanical systems with machine drives are essential
steps at the design stage of such systems. This paper describes the procedure
of deriving a model for the brush less dc motor with 120-degree inverter system
and its validation in the MATLAB/Simulink platform. The discussion arrives at a
closed-loop speed control, in which PI algorithm is adopted and the
position-pulse determination is done through current control for a standard
trapezoidal BLDC motors. The simulation results for BLDC motor drive systems
confirm the validity of the proposed method.
KEYWORDS:
1. PMBLDC
Motor
2. Simulation
and modeling
3. Speed
control
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Figure
1. PMBLDC motor drive system
EXPECTED SIMULATION RESULTS:
Steady state current
Figure
2. Stator phase currents
Back EMF of the BLDC motor
Figure
3. Trapezoidal back EMF
Figure
4. Reference current waveform
Figure
5. Representative phase voltage (van)
Figure
6. Torque and speed responses during startup transients
Figure
7. Torque and speed responses - step input change - moment of
inertia
0.013 kg-m2 (step time 0.5 S)
Figure
8 Torque and speed responses at moment of inertia 0.098 kg-m'
Figure
9. Torque and speed-Step input with moment of inertia 0.098
kg-m2
(step time 0.5 S)
Figure
10. Step load torque (9Nm) at 0.75 step
Figure
11. Step load torque (25 Nm) at 0.75
Figure
12. Application of heavy load (100 Nm)
Figure
13. Load toque 25Nm at step of 0.5
CONCLUSION:
The
nonlinear simulation model of the BLDC motors drive system with PI control
based on MATLAB/Simulink platform is presented. The control structure has an
inner current closed-loop and an outer-speed loop to govern the current. The
speed controller regulates the rotor movement by varying the frequency of the
pulse based on signal feedback from the Hall sensors. The performance of the developed
PI algorithm based speed controller of the drive has revealed that the
algorithm devises the behavior of the PMBLDC motor drive system work
satisfactorily. Current is regulated within band by the hysteresis current
regulator. And also by varying the moment of inertia observe that increase in
moment of inertia it increases simulation time to reach the steady state value.
Consequently, the developed controller has robust speed characteristics against
parameters and inertia variations. Therefore, it can be adapted speed control
for high performance BLDC motor.
REFERENCES:
[I] Duane C.Hanselman, "Brushless
Permanent-Magnet Motor Design", McGraw-Hill, Inc., New York, 1994.
[2]
TJ.E. Miller, 'Brushless Permanent Magnet and Reluctance Motor Drives.' Oxford
Science Publication, UK, 1989.
[3]
RKrishnan, Electric Motor Drives: Modeling, Analysis, and Control, Prentice-Hall,
Upper Saddle River, NJ, 2001.
[4]
P Pillay and R Krishnan, "Modeling, simulation, and analysis of permanent
Magnet motor drives. Part II: The brushless dc motor drive," IEEE
Transactions on Industry Applications, vol.IA-25, no.2, pp.274-279, Mar./Apr.
1989.
[5]
RKrishnan and A. J. Beutler, "Performance and design of an axial field
permanent magnet synchronous motor servo drive," Proceedings of IEEE
lASAnnual Meeting, pp.634-640,1985.
