Microcontroller Based Fuzzy Logic Speed Controller For Three Phase Induction Motor

Download or read book Microcontroller-based Fuzzy Logic Speed Controller for Three-phase Induction Motor written by Marwan A. A. Badran and published by . This book was released on 2013 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-phase induction motors have been used in a wide range of industry applications; since they are robust, brushless and have simple design. Furthermore, the speed of induction motor can be easily controlled by variable frequency drives. The continuous development in power electronics semiconductors came out with modern electric drives. These drives use high speed power transistors, like IGBT and MOSFET, with various switching techniques. The speed control of induction motor is important to achieve maximum torque and efficiency. In the past decades, conventional control systems, such as proportional-integral derivative (PID) controller, were applied to electric drives to control the speed of induction motor. The PID controller is not a well established control method in motor drive because of the nonlinearity of induction motor. On the other hand, the use of Fuzzy Logic Controller (FLC) improves the performance of the speed control of induction motor. In this research, a microcontroller-based fuzzy logic controller was developed. The FLC replaces the conventional PI controller to improve the speed response of the drive in order to keep the speed of the induction motor constant when the load varies within the operating range. The research also included the design and implementation of a three-phase voltage source inverter (VSI) driven by Space Vector Pulse Width Modulation (SVPWM) signal. The control system in this research was designed using Matlab/Simulink environment. The simulation included a comparison of speed response of FLC and PI controller. The input to FLC is the linguistic variable of speed error and change of speed error, while the output of FLC is the frequency fed to the inverter. The three-phase inverter was fabricated using MOSFET Hex-bridge connected to a low-pass LC-filter to smooth the inverter output voltage wave. In order to apply FLC and generate corresponding SVPWM signals a PIC16F877A microcontroller was used in the control system. The speed controller was tested using various values of input speed using simulation and experiments. The results showed the superiority of the proposed FLC over the conventional PI controller in the dynamics response of speed. The results also showed the ability of the proposed to generate a three-phase sine wave with desired frequency to control the speed of the induction motor with THD less than 5%.