Electromagnetic System Design And Optimization Of 270V DC High Power Relay

With the development of modern airspace types, the application scope of the high voltage and current relay is enlarged and the demand for them is growing. Especially the 270 V voltage platforms are widely used in space statio n, the forth generation warplane, airbus, etc. As a relay opens a high voltage and current load, a strong arc will generate between contacts,and intense arc ablation start. So how to increase the cyles of the relay has become the most common problem encoun tered in practical application. In the process of breaking load, a slight movement delay or blocking will seriously affect the arc ablation, and even cause the relay to be burned down.At present, products with high quality level mainly rely on import and the requirement for independent research and development seems to be increasingly urgent. Based on the comperhensive analysis of domestic and overseas electromagnetic systems and the spring force characterisitc determined by load, electrical life, environment index and so on, this paper investigate d the overall design, model building and parameters optimization of 270V/200 A relay’s electromagnetic system.On the basis of analyzing the features of present products electromagnetic system, the overall design of electromagnetic system was carried out. At first, the structures of electromagnetic type and permanent magnet type system were provided. Then, this paper explained the working principles of these two structures, and built the equivalent magnetic circuit models. According to magnetic circuit method and Maxwell electromagntic force equation, the attractive force worked on the armature was calculated. Finally, the optimal structure was determined by attractive force and spring force matching.With regard to the optimal structure of magnetic system, the paper built its two dimension finite element model. Afterwards simulated the static charactreistic of the magnetic system by magnetic field method, and verified whether the relay could pick up under the pick-up voltage or release under the release voltage or not. The eddy effect was analyzed and the dynamic charactistic model was given. Then the magnetic field simulating method for dynamic charactistic was provided considering eddy effect, and the dynamic charact istic of electromagnetic system was calculated. The calculation results with or without considertation of eddy effect were compared.Based on the static and dynamic characteristics simulation method, the paramters optimization design of electromagnetic system was realized. Firstly, determined the objective function through the matching condition between attractive force and spring force. Secondly, found the key parameters which have great influences on objective function by single factor impact analysis. Thirdly, optimized these parameters by inside and outside array and orthogonal design. Then determined the design paramters and their optimal central values, which have obvious effect on the quality characteristic by the analysis of vairance of signal noise ratio. Finally, the results were verified by dynamic characteristic simulation and prototype samples.