Investigation on an Axial Rotor-Staggered Permanent Magnet Reluctance Machine for the Shock Wave Device

To meet the harsh requirements of the motor for the shock wave (SW) device that is used in the shale reservoir stimulation, such as large torque density within the small radius-length ratio space and rugged structure to resist the impact of SWs, an axial rotor-staggered permanent magnet reluctance machine (ARS-PMRM) is proposed and studied in this article. It adopts an axially sandwiched permanent magnet rotor to weaken the axial SWs and uses the magnetic field modulation effect to improve the torque density of motor. By analyzing the influences of main motor parameters on the torque and the impact resistance, an ARS-PMRM with 12 slots and 10 rotor teeth is designed and optimized for the SW device. Its electromagnetic performance, loss, temperature rise, and impact resistance are compared with a fractional-slot concentrated winding permanent magnet synchronous machine (FSCW-PMSM) with the same size. Finally, the prototypes of two machines are manufactured and tested. The results indicate that the ARS-PMRM has similar torque density, efficiency, temperature rise, and manufacturability compared with the FSCW-PMSM, but it reduces about 38% permanent magnet usage and shows excellent resistance performance to SWs.