Research On Distributed Parameters Model Of Nonlinear Permanent Magnet And Its Applicatin In Bridge Magnetic System

Nonlinear permanent magnet (NPM), such as FeCrCo and AlNiCo, has a nonlinear hysteresis curve (2nd quadrant). The NPM is often used in minitype electromagnetic devices for its high temperature coefficient and good machinability, for example electromagnetic relay (EMR). It is widely used in military, aerospace field etc.In the process of parameters design and optimization process for electromagnetic devices which have polarized magnetic system and contain NPM, the accurate and efficient calculation of attractive force is a basic and important step. There are mainly two popular ways: finite element method (FEM) and magnetic equivalent circuit method (MEC). FEM has a high level accuracy but often costs a lot of time. MEC has the superiority in its calculation speed but disadvantages in accuracy. The design and electromagnetic system (EMS) calculation ability is on a low level. The basic foundation of NPM modeling method in MEC needs to be improved. Forces on the basic calculation infinite block and the modeling method, the method which has a fast calculation speed and acceptable accuracy will be meaningful for the reliability design of EMR.Firstly, based on the pricinple of magnetic flux tube, a distributed parameter calculation model (DPM) was established. The infinite block was built for rectangle NPM. The relationship between infinite blocks was deduced. The solution procedure as well as verification condition of this model was given; By a case study of the single rectangle NPM, the method of magnetic field lines division (MFLB) was present and adopted to build the permanent magnet DPM, the whole DPM model of rectangle NPM was built, the starting point and section magnetic flux of each subsection were solved; compared with FEM and test data this model proves to be of acceptable calculation accuracy and high calculation speed.Secondly, for the other typical shape of NPM—sector NPM, the distribution parameter model for sector NPM was researched; the gathering method for section flux distribution was present; a improved model for sector NPM were present based on the MFLB method the whole DPM model of sector NPM was built, the starting point and section magnetic flux of each subsection were solved; the calculation results of sector NPM were similar to FEM calculation data. This model was verified by FEM data.Thirdly, based on the research of open circuit NPM, the electromagnetic structure of a type of bridge polarized magnetic system (BPMS) was analized; the MFLB distribution parameter model was used to build the calculation model of BPMS; the finite block was built; the interface of rectangle NPM in BPMS was determined; a local region fine division method was present; the whole distribution parameter model of EMR was built; the leakage permeance calculation formulas were deduced; the static attractive force calculation method was analyzied; the newton method and the genetic algorithm method were used to calculate the force under different ampere-turn of0and±120At and different rotation angle of armature; compared with3D-FEM calculation data; the other parameters such as magnetic flux density and section magnetic flux were also calculated; the calculation accuracy was higher than2D-FEM and MEC, and the calculation time consumption was far less than3D-FEM.At last, according to the practical need in the research of distribution parameter model, the section magnetic flux test method for rectangle NPM was present; the test equipment was manufactured; the test for cylinder and annulus NPM were also realized at the same time; the test method for sector NPM was present too; cooperating with the servo control system the test equipment for sector NPM was manufactured for the special need of sector NPM; compared with the FEM test data, the equipment achieved the task accurately; the test method and the design thought for the section magnetic field image test of NPM were present; the control strategy for2D motion platform based on PLC was studied; the software and hardware of test system were realized based on the motion control platform; the automatic test of magnetic field image for rectangle NPM was realized.The research proposed in this paper are of important theoretical significance and practical value for the design, analysis and optimization of EMR which contain NPM, the basic thought and relevant key technology can be extended to other electromagnetic devices.