Dynamic characterization and position estimation of electromechanical contactors

This paper presents a rigorous model to simultaneously solving the mechanic and electromagnetic coupled differential equations which govern the dynamic response of the contactor. The model is validated with data obtained experimentally and therefore the accuracy of the model is validated. On the other hand, an estimator of the position and the velocity of the contacts, as well as of the moving core is developed. This estimator only uses available electrical variables, such as the voltage across the coil terminals and the current flowing through the coil of the contactor. Hence, by this way, a low cost microcontroller could be able to implement a control algorithm in order to reduce the undesirable phenomenon of the contact bounce, which causes severe erosion of the contacts and, as a consequence, the electrical life and reliability of the contacts are greatly reduced.