Submersible Tubular Linear Permanent-Magnet Synchronous Motor

Submersible linear pumping system is a new type of oil-pumping system. Tubular linear permanent-magnet synchronous motor (TLPMSM), which is also new itself, has become the ideal driving motor because of its optimal performance. In order to achieve the best driving performance, this kind of motor is comprehensively studied in this paper, including structure determination, parameters and unilateral magnetic force calculation, prototype design and test, and so on. Main contents are as follows:1) According to the actual operation environment and the performance requirements, the structures of stator core, stator windings and rotor magnets, and the ratio of poles and slots are determined by comparison, and the final structure of this TLPMSM is given.2) The MMF of this new TLPMSM is discussed using the analytical method. And the expressions of all its harmonic MMFs are given and then the resultant harmonic winding coefficients are obtained.3) Based on the new structure of this TLPMSM, the inductance parameters mainly including the slot leakage one and the harmonics one are calculated.4) The TLPMSM has no unilateral magnetic force when under ideal circumstances. Actually, the rotor deviation is inevitable for this kind of motor, so the unilateral magnetic force exists definitely, which is analyzed theoretically and verified by 3-D FEM in this paper.Finally, the TLPMSM design is discussed and a prototype is manufactured. The experiment results show good coincidence with the theoretical ones and a good machine performance.