A new dynamic displacement prediction method for contactors with constant air gap

Abstract

In order to improve the dynamic characteristics of the contactor, this paper proposes a new dynamic displacement prediction method for contactors with constant air gap. The dynamic displacement process can be predicted by observing the flux linkage produced by the permanent magnet. The equivalent magnetic circuit model of electromagnetic force driving actuator (EMFA) is established. The formulas of dynamic flux linkage, displacement and current are deduced, and the displacement prediction of the contactor is completed. The curved surfaces of driving force, flux linkage, displacement and current are established by finite element method. The movement process of the contactor is dynamically simulated by interpolation method. Finally, an EMFA-driven contactor is used for the experiment. Experimental results show that the new dynamic displacement prediction method is suitable for contactors with constant air gap. On the basis of sensorless control, bounce time of the contact can be effectively reduced by adjusting the PWM duty cycle and the corresponding displacement control parameters. The research in this article can be used to guide the design of future controllers. And the simulation results are consistent with the experimental results. The experiment verifies the effectiveness of the new dynamic displacement prediction method.