Research on zero-current interrupt technology of intelligent AC contactor

An intelligent AC contactor with the function of zero-current interruption based on PIC16F877 microcontroller was presented in this paper. This kind of intelligent AC contactor has features of intelligentization, controllability, benefiting from combining technologies such as electrical equipment, power electronics, microcomputers and sensors. It becomes a reality to break contacts without arc or with less arc by controlling the intelligent AC contactor, particularly by using zero-current interrupt control technology, leading to energy savings, low operating noise, high electrical span, and high operating frequency. The functions and performance of the AC contactor can be substantially improved and to meet the need of smart grid development. Key technologies such as the accuracy and stability of zero-current interrupt of three-phase contactor are also discussed in this paper. We expect this type of intelligent AC contactor to find broad applicability in power distribution systems, especially smart power grids.