Penulis
J. Kriauciunas, R. Rinkeviciene, A. Baskys
Judul
Self-Tuning Speed Controller of the Induction Motor Drive
Sumber
IEEE
Resume
Induction motors are characterized by non-linear, complex and time-varying dynamics therefore conventional controllers cannot ensure speed step response specifications in all speed range. This paper presents hybrid fuzzy and proportional-integral-derivative (PID) controller to improve speed control of the induction motor. Proposed Fuzzy logic controller is used to tune each gain of PID controller separately. The simulation results are presented and discussed in the study. Simulink based model of induction motor drive is used for analysis of developed electromagnetic torque and speed response. Motor performance is thereby evaluated for speed control.
The conventional PID controller is linear and can operate properly only in a certain point of all operating range. Developed and investigated scalar controlled sensorless induction motor drive simulation model with composite PID and fuzzy logic controllers. Such synthesis allows to control non-linear system and to tune gains of PID controller according to changing nonlinearity. Paper deals with simulation results of rotor speed and electromagnetic torque produced by motor are presented and discussed.
Usually scalar control method, which is also known as Volts -per-Hertz control (V /Hz ), is used to control an induction motors. If the ratio V /Hz remains constant with the change of frequency, then the maximum torque in speed-torque steady state characteristic remains constant. In actual implementation, the ratio between the magnitude and frequency of the stator voltage is usually based on the rated values of these variables, or motor ratings. However, when the frequency and also the voltage are low, the voltage drop across the stator resistance cannot be neglected and must be compensated. At frequencies higher than the rated value, the constant V /Hz ratio should not be applied to avoid insulation break-down, because the stator velocity should not to exceed its rated value.
Conventional PID operates only at one point of all speed range its gains should be recalculated. Elaborated speed control system simulation model with auto tuning fuzzy PID controller operates in all speed range from 1 rad /s up to synchronous speed 314 rad /s with steady state error ±0.05 %– ±5 %. Parameters of PID controller are tuned automatically by fuzzy controller according to speed error e and change of the error de . After the motor is loaded the speed drops down, but it took less than 5 s to adjust it to reference signal with smaller than 1 % error.
