Research on a Linear Permanent Magnet Brushless DC Motor for Electromagnetic Catapult

Linear permanent magnet (PM) brushless dc motor (LPMBDCM) is used for electromagnetic catapult, which may offer significant advantages, in terms of efficiency, high speed and accelerations of heavy payloads, capability of high forces, and so on. In this paper, an LPMBDCM, which is constructed of transverse flux stator and PM mover, is investigated. First, the launch specifications and technical features under the condition of pulse power input are presented. Then, the magnetic circuit parameters including the calculation of the mutual and leakage inductance are derived, and the rated work performances are analyzed. The rated input voltage, current, thrust, and power efficiency are 4000 V, 18041 A, 1.389 MN, and 0.97, respectively, which can meet the requirements of electromagnetic catapult. The availability and reliability are validated as the temperature rise per launch is lower than 1 °C, and the demagnetization of the PM would not happen with high pulse current. Finally, to validate the characteristic of the basic design, the system simulation model including the power supply and power conditioning is built using of Simulink, and the launch trajectory is simulated by the model, which shows the launch can achieve a speed of 99.47 m/s along the distance of 99.47 m within 1.51 s. A small-scale prototype machine is fabricated and the validity of the proposed method has been verified by the experimental results.