High-Performance Flux Linkage Closed-Loop Strategy for AC Contactors

In order to further improve the reliability of AC contactor operation, this paper designs a control strategy based on flux linage closed loop. Firstly, a flux linkage observer is designed based on the topology of the full-bridge driving circuit, with bus capacitance voltage and coil current as inputs. Subsequently, a flux linkage closed-loop control strategy is developed. Before making, the coil resistance is automatically identified. During the making process, only a suitable flux linkage reference value needs to be set to realize the automatic flux linkage weakening and contact bounce reduction. During the holding stage, the noise adaptive suppression strategy is adopted, which can better suppress high-frequency noise. In the breaking stage, the magnetic circuit is reversed excited to enhance the ability of breaking the circuit. The control strategy proposed in this paper can effectively improve its control performance, simplify the control difficulty, and is of great significance for the intelligent control of the contactor.