DESIGN OPTIMIZATION OF INVERTER FED SQUIRREL CAGE INDUCTION MOTOR

Abstract

This dissertation wort: deals with the design optimisation of inverter fed squirrel cage induction motor . For this a set of independent variabless are selected and sui tail e cor:stwdinfS are imposed on the design to make it feasible and practically acceptable. The constraints which found suitable to be imposed are P.U. torque pulsation, rms voltage across the commutating capacitor, maximum commutation time, maximum flux density in various Parts Of magnetic circuit of machine, full load slip and stator and rotor temperature rise. As the inverter output is rich irs various harmonics, hence additional losses caused by these harmonics, along with stability problem of machine are also matter of great concern. To have efficient and stable drive, these two effects of higher harmonics are also minimized. The design is optimized considering cost of machine torque pulsations as objective functions. The design optimization of squirrel cage induction motor is a highly nonlinear programming problem. Therefore, a suitable optimization technique to solve this problem must be capable to optimize a nonlinear rnultivariable canstrained optimization problem. In this work, sequential unconstrained minimization technique tS U H T) with interior penalty function approach is used to optimize the design_ In this method, Rosenhrock ' s method is used to obtain Unconstrained minimization.