Optimal energy control of three phase induction motor drives

Abstract

Three-phase induction motors are the work horse of the industries and comprise almost 70 % of all the industrial loads. This has brought the need for the development of high energy efficient induction motor drive system, both at the design level and the performance level. The performance of the machine is good when the machine is running at its rated speed and torque. But in the lower torque region, the performance of the machine gets deteriorated. The iron losses become dominating resulting in the reduced efficiency of the system. To improve the performance of the drive system, research has been already carried out in the areas of machine design and core materials. However, there is a need to develop the optimal control techniques for better performance of the drive system. newline newlineThis research work investigated the application of optimum flux controllers to achieve high efficiency of induction motor drive system under part-load conditions. The input power of a vector controlled 1HP induction motor is investigated with four topologies namely constant flux operation, flux controller using Particle Swarm Optimization, search control and hybrid controller in steady-state conditions. To enhance the stability of the motor drive during variable speed and load operation PI controller is used. It is clear from the test results that the hybrid flux controller is giving best results when compared with other controllers. With the application of hybrid controller, 100W power is saved in the simulated motor. Since the power rating of the industrial motor is high, considerable amount of saving is possible. newline newlineIn this work, the suitability of the optimum controllers in the economics of a vector controlled 100 hp induction motor in variable load/speed applications is studied. It is noted that PSO produced better results than V/f in all instances (motor load and speed). From the case study, US $ 529536 per 100 hp motor for mine hoist load diagram can be saved when we used PSO controller over V/f controller to select optimum flux l