Multi-field Coupling Study Of High-power Water-cooled Permanent Magnet Eddy Current Governor

Permanent magnet adjustable speed drive(PMASD)is the most representative electromechanical equipment integrating Mechanical,Electromagnetism,Thermodynamics,Material science and Hydrodynamics.It has good prospects for application and has been listed as key products for promotion of national energy saving targets instead of electrical transmission equipment gradually.Currently,the research on PMASD is mainly focused on the unilaterally numerical calculation of the magnetic field,eddy current field and temperature field to optimize operating characteristic.In the high-power PMASD,the method will cause large error with ignoring influence of the flow field and the coupling relationship of each physical field.So,it's very important to study on the multi-field coupling of PMASD.The magnetic finite element analysis of high-power PMASD is executed firstly by Ansoft software,and the magneto-thermal coupled model is built by Ansys-workbench software.The eddy current loss from electromagnetic analysis is imported as heat source into steady-state thermal analysis to achieve the heat flux distribution of outer surfaces of conductor tube.The two-dimensional finite element Flow field of PMASD is analyzed by Fluent software with present the two-ways heat-flow coupling method to revise the heat transfer coefficient of the outer surface in conductor tube.Based on the heat transfer coefficient corrected by the two-ways heat-flow coupling numerical calculation method,the two-ways magneto-thermal coupled model is built with conductivity and thermal conductivity which varies with temperature of the circle conductor.Then,the magneto-thermal-flow multi-field coupling numerical simulation system of the high-power PMASD is created to calculate the temperature distribution.The experiment is conducted to test the output torque of high-power PMASD and the exit water temperature of Water cooling system.The result shows temperature distribution and torque of high-power PMASD by the multi-field coupling system accords well with measured value.The two-dimensional magneto-thermal finite element coupled model is built based on the result from multi-field coupling system.A response surface optimization model of PMASD with the constraint of pallet thickness,permanent magnet thickness,copper ring thickness,and conductor tube thickness is presented to maximize utilization rate of permanent magnet and minimize the temperature of conductor tube.Lastly the optimized structure parameters of high-power PMASD are achieved by the genetic algorithm.