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Effects of different parameters on the electromagnetic repulsion mechanism are analyzed in order to design an effective high speed contact mechanism. The mathematical model of the electro-magnetic repulsion mechanism is established and a finite elements simulation software is used to calculate the repulsion force of the electro-magnetic repulsion mechanism. Simulation results show the effects of different parameters on the electro-magnetic repulsion mechanism. A high speed contact mechanism is designed for DC320V/3kA hybrid switch. Experimental results show that the mechanism is able to separate within 220us, and it takes 7.6ms for 20mm contact gap. It meets the demand of hybrid switch for high reaction speed and high motion speed.

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To solve the problem of the high rising rate and large peak value of the expected current of the short-circuit current in marine DC power system faults, a hybrid DC current limiting circuit breaker scheme based on a high-speed electromagnetic repulsion mechanism is proposed. A parameter selection model is constructed by comprehensively considering the short-time withstand of the thyristor, the volume of the commutation circuit, and capacitor energy, and the optimal value of the commutation circuit parameters at a certain voltage level is obtained. The finite element mathematical model of the high-speed electromagnetic repulsion mechanism is established by coupling the electromagnetic force field, which enables the deformation process of the mechanism under the condition of high acceleration to be considered. The von Mises yield criterion is adopted as the mechanical boundary condition in the design of a high-speed electromagnetic repulsion mechanism, which solves the problem of the long inherent time of opening. The experiment platform is built, and the experiment under the fault condition with a current rising rate of 20 A/μs is completed. The arcing time, commutation time, zero-voltage recovery time, and contact movement characteristics are obtained, which meet the design requirements, verify the effectiveness of the analysis, and lay a solid foundation for further research and development of the current limiting circuit breakers for medium voltage DC systems.