| Contactor is a kind of widely used switching device, which is used in automatic control circuit because of its low cost, strong overload ability and so on. In recent years, domestic and foreign scholars have done a lot of research on intelligent AC contactor, because of the timeliness and dispersed of the action mechanism, as well as the large bounce in closing process and arc in breaking process are superimposed on each other, once the control system output occurs error, the no bounce closing and no arc breaking will not be able to achieve. On the basis of this problem, this paper presents a new type structure of three phase independent electromagnetic system and a closed-loop control method. The structure of each phase electromagnetic system is smaller. Each one can be controlled by the excitation voltage, which can be adjusted in real time by the closed-loop control system, the controlled object is the displacement of dynamic core. This method is carried out through the experimental analysis.In this paper, the structure of intelligent synchronous AC contactor is introduced, and the size and area of the coil are determined by calculating the parameters of the electromagnetic system. By means of finite element analysis, the force analysis of the shell has been done in order to ensure the reliability of the shell in the force process and avoid the waste in the actual processing. At the same time, the spring reaction parameters are designed, and the dynamic characteristics of the electromagnetic system under the control of open-loop are analyzed by the method of field-circuit.Secondly, based on the dynamic characteristics analysis of open-loop control, the displacement of moving core is set as the controlled object to design the closed-loop control system, proposed the moving core in the process of attracting five phase type displacement planning and breaking process of three phase type displacement planning, then optimize the PID parameters. Based on the field-circuit method for simulation, the no bounce in closing process and no arc breaking are achieved.Eddy current displacement detection circuit and AC current zero-crossing detection circuit based on Hall switch, the accuracy of the zero-crossing detection device is verified through experiments, this method make up the lack of traditional testing methods. Finally, the hardware circuit and software process flow of the control system are designed. This design improve the overall performance of the contactor, also extend the service life of the contactor, achieving a safe and economical power construction in a certain role and significance. |
