Bi-criterial optimization in induction motors speed control taking into consideration the electromagnetic transients

The paper presents a solution of the problem of simultaneous time and energy losses minimization during the frequency speed control of induction motors, taking electromagnetic transients into consideration. To solve this bi-criterial optimization problem, the optimization index in the form of a linear combination of scalar indexes, is assumed and the Pontryagin maximum principle is used. To obtain an explicit description of the control, i.e. the amplitude and frequency variation of the motor supply voltage or current as function of time, the authors used a parametric optimization algorithm based on the Gauss-Seidel method to solve the two-point boundary value problem. A numerical example is provided to demonstrate the effectiveness of the proposed solution of this optimization problem.