Abstract:
The control and estimation of A.0 drives in general are considerably more complex than those of dc drives, and this complexity increases substantially if high performances are demanded. The main reasons for this complexity are the need of variable frequency, harmonically optimum converter power supplies, and the complex dynamics of ac machines, machine parameter variations and difficulties in processing feed back signals in the presence of harmonics. With the advancements of power electronics, digital signal processor technology and different control strategies, a.c drives becomes more efficient.
Indirect field-oriented control (IFOC) method is widely used for IM drives. By providing decoupling of torque and flux control demands, the vector control can navigate an AC motor drive similar to a separately excited DC motor drive without sacrificing the quality of the dynamic performance. Within this scheme, a rotational transducer such as a tachogenerator, an encoder or a resolver, was often mounted on the IM shaft. However, a speed sensor cannot be mounted in some cases, such as motor drives in a hostile environment or high-speed motor drives. Also such sensors lower the system reliability and require special attention to noise. Therefore, sensors less induction motor (IM) drives are widely used in industry for their reliability and flexibility, particularly in hostile environment.
In this work, a comprehensive mathematical modeling of vector controlled induction motor drive (VCIMD) system with speed sensor and with out speed sensor has been carried out to investigate the performance of drive system. VCIMD has been implemented using both Fuzzy and PI controllers. The dynamic response of VCIMD under various operating conditions such as starting, speed reversal and load perturbation is simulated and examined in MATLAB 7 environment using Simulink and power system block set toolboxes.
