Design and Analysis of Permanent Magnet Vernier Motors for Downhole Applications

In downhole applications, it is promising to use direct-drive permanent magnet motors instead of traditional asynchronous motor plus reducer, from the viewpoint of efficiency and reliability. Because of the advantages of simple structure and high torque density, permanent magnet vernier motor is very suitable for low speed and high torque applications.A permanent magnet vernier motor(PMVM) with consequent pole rotor is designed by finite element method, and several important parameters influencing the performance are investigated. The simulation results show that compared with the surface mounted PMVM designed earlier, the consequent pole structure not only meets the requirements of torque density, but also improves the reliability of the rotor structure and saves the consumption of permanent magnets by 47%.