10-11-2014, 12:49 PM
Abstracts: Because of the low maintenance and robustness induction motors have many applications in the industries. The speed control of induction motor is more important to achieve maximum torque and efficiency. Various speed control techniques like, Direct Torque Control, Sensor-less Vector Control and Field Oriented Control are used for controlling them. Programmable Logic Controller can be used for the speed control of induction motor to achieve maximum torque with minimum loss. It provides better control of motor torque with high dynamic performance. The result concludes that the efficiency and reliability of the proposed speed controller is good. Ac Induction motors are being applied today to a wider range of applications requiring variable speed. Generally, variable speed drives for Induction Motor (IM) require both wide operating range of speed and fast torque response, regardless of load variations. This leads to more advanced control methods to meet the real demand. The conventional control methods have the following difficulties. It depends on the accuracy of the mathematical model of the systems. The expected performance is not met due to the load disturbance, motor saturation and thermal variations. Classical linear control shows good performance only at one operating speed. The coefficients must be chosen properly for acceptable results, whereas choosing the proper coefficient with varying parameters like set point is very difficult. To implement conventional control, the model of the controlled system must be known. The usual method of computation of mathematical model of a system is difficult. When there are system parameter variations or environmental disturbance, the behavior of the system is not satisfactory. Usually classical control is used in electrical motor drives. The classical controller designed for high performance increase the complexity of the design and hence the cost.