Optimale efficiency control of linear induction motor for linear metro

In this paper, a new approach is proposed that minimizes the total copper and iron losses in variable speed and/or thrust force of linear induction motor (LIM) drive. This method is based on a LIM model that considers the end effect and attraction force. For a given speed and load this model allows the establishment of equations to quantify copper and iron losses, and the relationship between stator field and torque currents for minimum total loss can be deduced. Based on these equations, a loss minimization control algorithm, combined with vector control strategy to drive the LIM, is proposed. In order to reduce the effect for the transient performance, a switch control method is proposed. This algorithm allows the electromagnetic losses in a variable speed and/or thrust force LIM drive to be decreased while keeping a good transient response. Simulation results show the validity of the proposed control strategy compared with the traditional vector control method. Experimental results show that the efficiency of LIM is improved a little because of the inexactitude parameter of LIM. The experimental results show that the proposed control strategy has good transient and steady performance.