Majosta Induction Machine: Analysis and Performance Using Fuzzy Logic Controller

The control and estimation of A.C 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 for variable frequency, harmonically optimum converter power supplies, and the complex dynamics of ac machines, machine parameter variations, and difficulties in processing feedback signals in the presence of harmonics. With the advancements of power electronics, digital signal processor technology, and different control strategies, a.c drives become more efficient. In recent years, the application field of Indirect field-oriented control (IFOC) and Direct Torque Control (DTC), a variation of vector control, of induction machines has greatly increased in the areas of the traction, paper, and steel Industry, and so on. The main limitations of the conventional DTC are large torque current ripples and variable switching frequency. These disadvantages can be overcome by using Fuzzy Space Vector Modulation (FSVM). Direct Torque Control of Induction motors using fuzzy-based SVM has been adopted for the present study. The current ripple and Flux error can be reduced by using fuzzy-based SVM as compared to classical DTC. In this book, these comparative features have been highlighted, through MATLAB simulation. The 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 tacho generator, 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 book, a comprehensive mathematical modeling of vector-controlled induction motor drive (VCIMD) system with speed sensor and without 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, speed re-reversal and load perturbation is simulated and examined in MATLAB environment using Simulink and power system block set toolboxes.