This paper presents the comparative study between PI, fuzzy and hybrid PI-Fuzzy controller for speed control of brushless dc (BLDC) motor. The control structure of the proposed drive system is described. The simulation results of the drive system for different operation modes are evaluated and compared. A fuzzy controller offers better speed response for start-up while PI controller has good compliance over variation of load torque but has slow settling response. Hybrid controller has an advantage of integrating a superiority of these two controllers for better control performances. Matlab/Simulink is used to carry out the simulation.
3. Hybrid Controller
4. BLDC Motor
5. Speed Control
Figure 1: Simulation model BLDC motor drive
EXPECTED SIMULATION RESULTS:
Figure 2: PI controller
Figure 3: Fuzzy controller
Figure 4: Hybrid controller
Figure 5: Comparison of speed response
Figure 6: PI controller
Figure 7: Fuzzy controller
Figure 8: Hybrid controller
Figure 9: Comparison of speed response
From simulation results, it was shown that PI controller maintained the steady state accuracy while the fuzzy controller performed well in the case of sufficiently large reference input changes with shorter settling time. The hybrid controller has integrated both fuzzy controller and PI controller. During the large speed error, the fuzzy controller will be selected by switch. When the speed error is less than 0.28 rpm, the PI controller will be selected to maintain the high steady-state accuracy. The simulation results showed that the hybrid controller has incorporated advantage of both fuzzy and PI controller. As a conclusion, the hybrid controller has improved the dynamic performance of BLDC motor.REFERENCES:
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 L.S. Xuefang, F. Morel, A.M. Llor, B. Allard, J.-M. Retif, "Implementation of hybrid control for motor drives", IEEE Trans. Industrial Electronics, vol.38, No. 5, pp. 1210-1218, Sep. 2002.
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