Design methodology of optimal trajectories minimizing loss of induction motor under torque amplitude limit

In order to drive the electric machines using the motors efficiently, the energy loss should be minimized during its operation. It has been reported that the design methodology of the optimal torque and rotating speed trajectories to minimize the energy loss of the induction motor (IM) drive system when the operation time period, rotating speed range, and rotational angle are given as drive conditions. However, the amplitude of the obtained optimal torque trajectory may exceed the maximum rating torque of the motor. This paper proposes a design methodology of the optimal motion trajectory for IM drive system by means of the variational method and the Newton-Raphson iteration when the torque amplitude limit is given as additional constraint conditions.