Abstract:
A lot of efforts have been directed for optimization of electrical machine design. Among them the diverse types of electrical machines, the transformer and motor are commonly used ones. However their design procedures are changing and complexity of ne aspects of their applications is growing. One of the objectives of this thesis work is to find out the techniques of improving some vital parameters and characteristics of three phase high power transformers. For the transformers these are reduction to rational value of leakage flux and optimum designing of electromagnetic shield, loss performances. The large number of non-explicit expression has been incorporated in the standard routine to obtain compact user friendly software, capable of giving the design solution in minimum computer time. The standard software available for optimization of mathematical functions is not directly applicable for machine design. The objective functions cannot be uniquely formulated and in some cases compound objective functions including effective cost, efficiency, weight, temperature rise, mechanical and electromagnetic withstanding capability, noise and loss reduction, harmonics, speed control etc, have to be formulated.
The constraint functions are highly nonlinear and cannot be expressed as explicit functions of the decision variables; even the decision variables are not uniquely defined. The non-explicit objective functions and constraint s are properly fed to the optimization program to get the solution in most handy form. Designing has been carried out for various capacities of high power transformers to assess the effectiveness of the software and it limits of covered ranges of size and power of the machine. The optimization program based on Quasi-Newton method has been used because of its capability of fast convergence, handing of large scale problems and giving global minimum point. The developed software based on inclusion of new aspects of designing may be fruitfully used for machine designing purpose in our local electrical machine manufacturing plants.
