Structural Design And Experimental Study Of Novel DC Circuit Breakers Based On Pulse Electromagnetic Force

As a backup protection switch for a battery-type pulse power supply system of Wuhan National Pulsed High Magnetic Field Center(WHMFC),the DC circuit breaker is of great significance for the stability,safety and reliability of the long-pulse magnet power supply.Although a large number of researches and experiments have been conducted on DC circuit breakers all over the world,the arc extinguishing problem is difficult to be solved because the DC current has not a natural zero-crossing.Therefore the development and application of explosive DC breakers is still in the minority.A method for shutting off explosive DC breakers based on pulsed electromagnetic force is proposed in this paper,which can replace the explosion force of explosives and gas-water explosion force to drive the mechanical structure deformation,fracture and separation,and then cut off the DC circuit to achieve backup protection.Firstly,through the introduction of the electromagnetic forming technology and the shut-off principle of the aluminum wire electric explosion switch,the basic structure of the electromagnetic coil and aluminum tube with V-shaped slots and corresponding support accessories as circuit breakers are proposed,and the principle of shut-off of explosive DC breaker is discussed in detail in this paper,and through the circuit analysis of the circuit breaker action equivalent circuit and MATLAB simulation waveforms,the main component selection of the trigger power system was completed.Secondly,in order to complete the aluminum bucket structure design,the slotting method and the support ring assisted control strategy are proposed.During magnet coil design and winding process,a method of magnet top routing and epoxy casting is proposed.The design of new components and the three-dimensional assembly of the new DC circuit breaker were completed by Solidworks software,and finally a prototype DC breaker is built.The effects of current environment on the deformation of aluminum tube were investigated through the electro-plastic tensile test of 6061 aluminum alloy.In the explosion-type DC circuit breaker reliability experiment platform,the electromagnetic coil no-load reliability test and the comparison of the shutdown performance between the annealed aluminum tube and the unannealed aluminum tube were completed.Finally,the experimental results of the successful breaking of the annealed aluminum tube and cutting off the main circuit were realized under the experimental conditions of 480uF/10 kV,and the stability and reliability of the circuit breaker mechanical structure have been verified.