Investigation On Dynamic Characteristic Modeling Of High Power Dc Contactor And Its Optimization Method

As one type of the automated control apparatuses, DC contactor is the fundamental part of mechanical and electrical industries, and is playing indispensable roles in the national economy, by guaranteeing the normal function of low voltage systems. The design of high-power DC contactor integrates disciplines like mechanics, electricity, magnetic and so on, making it a difficult task. So far the traditional method still takes the real product as the guidance of design by means of trial and error, not only resulting in a long period of inefficient product design and study, but also a product with a higher cost that can hardly meet the aimed targets at parameters like electricity lifetime and performance. Problems encountered in this method cannot be solved theoretically either. The quality of dynamic characteristic is one important factor affecting the performance and electrical lifespan of DC contactors. So the research on it using virtual prototype has significant importance to the analysis and optimization of high-power DC contactors.Study on high-power DC contactor with double windings in series is carried out in this paper, based the analysis of the structure in high-power DC contactor and the technique of virtual prototype. The static quality of mechanical reaction force was analyzed and equivalent circuit model of the double windings in series was built. After all the dynamic characteristics analysis model was set up using the virtual prototype technology, study and optimization of DC contactor was carried out, to improve its reliability and electrical lifespan.Using multi-software co-simulation method, the dynamic analysis model of high-power DC contactor was built up as follows. Based on the multi-body kinetics simulation software ADAMS the mechanical model was built. The electromagnetic FEM software FLUX was used to calculate the electromagnetic force applied on the DC contactor. Flexible bodies were modeled in FEM software ANSYS for reeds. And MATLAB/Simulink was adopted to couple the electromagnetic system and mechanical system.The dynamic performance is influenced by parameters in mechanical structure and electromagnetic systems. Based on the virtual prototype of DC contactor, orthogonal experimental design method was applied to optimize the making and breaking velocity of the movable contact in the DC contact as a function of seven parameters like the angle of connecting reed, the stiffness and preload force of the main spring and the spring at main contact, the diameter of the magnetizer. So the most important parameters influencing the dynamic character were selected. What is more, the multiple linear regression function between the velocity of movable contact and the selected parameters was established using the uniform experimental design method to testify the model.The velocity of movable contact is the reflection of dynamic characteristics. Combining the traditional computation and the FEM technique, a rapid and accurate method was proposed. Choosing the velocity of movable contact as goal and genetic arithmetic as method, the key parameters affecting the dynamic characteristics was optimized. After the optimization, the making velocity is decreased and the breaking velocity is increased.The thoughts and methods used in this paper can also be applied to the design and optimization of other kinds of switch appliances.