A distributed parameter model of open circuit nonlinear permanent magnet bars based on magnetic field lines

The parameter design of electromagnetic devices which contain nonlinear permanent magnet (NPM) like AlNiCo and FeCrCo, often needs the calculation on magnetic force of thousands of times. It will cost a lot of time when using the finite element method (FEM). And the accuracy is limited when the magnetic equivalent circuit method (MEC) is used. In order to solve the problem, a distributed parameter calculation model (DPM) of NPM bars was established in this paper, and the solution procedure as well as the verification condition of this model was given. By a case study of the single NPM bar, the method of magnetic field lines division was adopted to build the permanent magnet DPM, solve the starting point and section magnetic flux of each subsection, make a comparison between FEM and test data, and verify the accuracy of this magnetic field line based the distributed parameter model in NPM bar calculation. This model proves to be of acceptable calculation accuracy and high calculation speed.