Calculation Analysis And Parameter Optimization Of Magneto-thermal Coupling Field Of Brushless Auxiliary Exciter

The permanent magnet brushless auxiliary exciter usually plays a critical role in the three-stage thermal power generation system.As the power supply of the entire system,the permanent magnet brushless auxiliary exciter makes the entire power generation system brushless,and can effectively reduce the cost of maintenance,also it can make the entire power generation system get better safety performance and fewer cost.Due to the use of permanent magnet materials,permanent magnet motors make the body smaller,save materials and reduce costs,and are the best choice for auxiliary exciters.After summarizing and analyzing the domestic and foreign literature,also considering the practical role of the auxiliary exciter,this paper determines the optimal design route for the permanent magnet auxiliary exciter.Taking a permanent magnet auxiliary exciter with a rated capacity of 7.794 k VA as the research object,on the basis of mastering its basic principles,structure,electromagnetic relationship,and heat calculation,use Maxell to establish both two-dimensional and three-dimensional finite element model,simulate its no-load voltage characteristics,and simulate its performance under rated conditions through the method of magnetic coupling,and compare the simulate conclusion with practical experimental value,verify the effectiveness of the finite element simulation.The loss simulation results obtained from electromagnetic field simulation are used as the heat source and imported into Workbench software to simulate the magnetic and thermal coupling field of the brushless auxiliary exciter.According to the actual situation,set the boundary conditions for each boundary of the auxiliary exciter,and compare the two-dimensional and three-dimensional models.The temperature field is simulated and compared with the experimental value to verify its correctness.Finally,through the simulation analysis of the permanent magnet auxiliary exciter as a means,combined with the special purpose of the auxiliary exciter,the output voltage and voltage adjustment rate of the permanent magnet auxiliary exciter is optimized when the permanent magnet auxiliary exciter works,and the width of the magnet and the shape of the pole shoe are used as the optimization target.Variables,optimized calculation under the reasonable structure of the auxiliary exciter,and finally improved the output efficiency of the auxiliary exciter and reduced the sinusoidal distortion rate.In this paper,the electromagnetic field and temperature field of the permanent magnet auxiliary exciter have been analyzed by using both two-dimensional and three-dimensional models,the characteristics under no-load conditions and rated load conditions are integrated.The final design results reduce the voltage regulation rate and sinusoidal distortion.At the same time,it increases the output voltage and current of the auxiliary exciter,which is of practical significance to the design of the permanent magnet auxiliary exciter and even the three-stage excitation system.It also provides a basis f or further research on the same type of motor.