Analyzing the core drive system and the particularity of electromagnetic catapult, the authors propose a new drive method for catapult, a double-sided linear induction motor with constant frequency and varying pole pitch. Based on the technical requirement of catapult index, the equivalent circuit of a long primary double-sided linear induction motor, and the electromagnetic thrust equations, the authors establish a finite element simulation model to analyze the effect of pole pitch, length of the secondary, coil turns, current frequency on electromagnetic thrust output, and validate the superiority of the proposed drive system. Structure parameters, as well as application of the double-sided linear induction motor with varying pole pitch is provided and discussed.

variable pole distance, linear induction motor, motor parameters, grade power supply