Analysis of Dynamic Characteristics of Permanent Magnet Contactor With Sensorless Displacement Profile Control

A new displacement profile control strategy based on pulse-width-modulation (PWM) for improving the dynamic characteristics and reducing the contact bounce of permanent magnet (PM) contactor during the making process is reported. Sensorless method of real time displacement signal detection is realized using magnetic circuit model (MCM) and electric circuit model (ECM). Finite element method (FEM) is used to obtain the nonlinear relationships among the flux linkage, displacement and current off-line. The information is then used for subsequent fast simulation of the dynamic characteristics of the contactor. A set of periodically inter-transferred dynamic characteristic equations are built and the complete making dynamic process of the PM contactor is simulated using 4th-order Runge-Kutta method. Experiments are carried out to validate the proposed control method on a prototype.