The Self-Correcting Control Strategy of a Single Flux Linkage Closed Loop for a Contactor

For the first time, a single flux linkage closed-loop control scheme for contactors using fast excitation control is proposed. The integrated observer and closed-loop state observer are designed to observe the flux linkage during the making and closing processes, respectively. After the contactor finishes the making and closing processes under the initial flux linkage control, it enters a self-correcting process that involves decreasing the flux linkage step by step. Two observers are used interchangeably to ensure the accuracy of flux linkage observation in this process; once the decrease in flux linkage becomes insufficient for maintaining the contactor in the closing state, the movable core separation signal is captured in time, and the critical flux linkage is determined based on the flux linkage jump of the closed-loop state observer. Then, the fast response of the single flux linkage closed-loop control can ensure the timely application of short-time and intense excitation and prevent the continued rebound of the movable core before contactor separation. Comprehensive use of the above methods enables the development of the self-correcting control strategy of a single flux linkage closed loop for a contactor. This result is of great significance for automatic bouncing inhibition and energy-saving optimization of contactors.