Research On Performance Of PMD Based On Improved Finite Element Analysis

Permanent Magnet Device(permanent magnet device, PMD) has advantages of simple structural, controlled start, adapting the harsh conditions and so on, it is gradually replaced by other power transmission equipment using in each field of modern industry. At present, the main research direction of PMD is the optimization and calculation of the internal magnetic field and transmission performance based on the finite element method, but the magnetic field analysis of PMD ignores the influence of the temperature field, structure, etc, it has large error between the calculation results and the measured value, therefore, how to carry out the finite element analysis for the coupled multi-physics is an important goal of this research field.Firstly, this paper uses the Ansoft software to simulate and calculate the magnetic field of PMD, but the torque calculation of magnetic field finite element analysis ignores the copper eddy current impacting on performance of PMD. Therefore, the paper proposes the method based on electromagnetic-thermal finite element analysis, with Ansys Workbench software establishing the model of electromagnetic-thermal coupling, considering the effect of copper eddy current on the performance of PMD, taking the eddy current thermal power of electromagnetic field computation as the heat source importing into the temperature field, and simulating the temperature field of PMD in the transient thermal model, after getting the model temperature distribution, for correcting properties of the performance parameters to simulate the magnetic field of PMD again. Finally, the error is smaller and the output torque is more practical engineering value and actual value.Then, to analyze the torque characteristics of PMD, with the analysis of magnetic coupling force proposes the basic theory of critical torque, and analyzing the process of overload start and rated load start, getting the maximum load torque value based on the calculation method of electromagnetic field and electromagnet-thermal coupling.Finally, analyzing the transmission efficiency of PMD, because of the transmission efficiency based on the slip calculation ignores the eddy current loss in the transmission,therefore, proposing a new method to calculate the transmission efficiency based on the eddy current power, the power loss of PMD is produced by copper eddy current in transmission,with simulation obtaining the eddy current transmission power and eddy current thermal power, and calculate the transmission efficiency of PMD.