Rotor Design And Optimization Of Submersible Permanent Magnet Assisted Synchronous Reluctance Motor And Analysis Of Electromagnetic Noise

Submersible motor is the core component of submersible pump,which is widely used in the field of national security water prevention and control,and consumes a lot of electric energy every year.With the proposal of the latest national energy efficiency standard,the energy-saving transformation of the motor has become the focus of attention,and the traditional submersible induction motor is facing the great challenge of upgrading.In this paper,a design and optimization method of permanent magnet assisted synchronous reluctance motor(PMa Syn RM)rotor is proposed.Combined with the high efficiency remanufacturing technology,the squirrel-cage rotor of submersible induction motor is replaced to make it a submersible PMa Syn RM.It can not only improve the efficiency of the motor itself,but also improve the efficiency of the whole submersible pump system through the way of speed regulation.A 55 k W wet submersible motor as is taken an example to study the the design method of PMa Syn RM rotor with the stator and winding unchanged.With the new rotor,the efficiency of the motor is improved,and the torque ripple and electromagnetic noise are smaller,which meets the requirements of environment-friendly and high-efficiency intelligent submersible equipment.The work of this paper mainly includes the following aspects:1.On the premise of keeping the original stator and winding scheme unchanged,the rotor scheme of the PMa Syn RM is redesigned.The effects of the number of flux-barrier layers,the size and location of flux barriers,and the arrangement of permanent magnets on the performance of the motor are studied.The electromagnetic design scheme of the rotor is determined,and the demagnetization of the permanent magnet is checked.The results indicate that the reformed submersible PMa Syn RM has higher power factor and efficiency.2.The types and causes of torque ripple are analyzed.The virtual permanent magnet harmonic machine model and adaptive optimization algorithm are used to optimize the flux-barrier ends’ widths and angles to mitigate the flux density harmonics caused by the rotor permeance,and reduce the reluctance torque ripple.The method of rotor axial segment staggering and harmonic current injection is used to suppress the permanent magnet torque ripple and the coupled reluctance torque ripple.The finite element simulation results show that the torque ripple is effectively reduced.3.The types and causes of radial electromagnetic force waves of submersible PMa Syn RM are analyzed.The force wave table is constructed by using the rotor harmonic characteristics obtained from the virtual permanent magnet harmonic machine model and the stator harmonic characteristics obtained from the traditional analytical method.It is verified by the two-dimensional Fourier transform results of finite element simulation.Compared with the radial electromagnetic force wave of submersible induction motor,it can be inferred that the electromagnetic noise level of submersible PMa Syn RM is lower.The results of multi-physics coupling finite element simulation verify the conclusion.