Study on the Characteristics of a Novel Six-Phase Fault-Torrent Linear Permanent Magnet Machine for Linear Oil Pumping

A six-phase fault-torrent primary permanent magnet linear machine is proposed for linear oil pumping. The proposed linear machine can save the permanent magnet with both the magnets and armature windings placed in the primary. Six-phase structure is used to increase the fault tolerance capability and reduce detent force. First, the structure of the proposed linear machine is given out, and the operation principle is analyzed as well as compared with an existing three-phase flux-switching permanent magnet linear machine. Second, the transient finite-element method is implemented to study on the thrust performance under normal and fault condition. In addition, based on the static characteristics, the motion law of landing top of linear pumping unit is analyzed, and the process is simulated by using the proposed linear machine. All the results indicate that the proposed machine has advantages of simple structure, minor thrust ripple, higher fault tolerance capability, and low cost. This kind of linear machine is well suitable for the application of linear oil pumping.