Research On Realization Method Of High Stability Flat-top Pulsed Magnetic Field Based On Magnetic Coupling

Strong magnetic field has become one of the more and more important extreme experimental conditions in modern science.At the same time,with the development of highpower terahertz sources,nuclear magnetic resonance and other frontier scientific experiments,people have more requirements for the stability,strength and duration of the magnetic field,so the flat-top pulsed strong magnetic field technology has been proposed and studied in depth,which has high stability while maintaining high field strength.In order to achieve a highstability flat-top pulsed magnetic field,a combination of high-frequency compensation power supply and high-current main power supply is generally used.After the main power supply current(magnetic field)reaches the flat-top stage,the compensation power supply will compensate for it to increase the ripple level..However,none of the existing flat-top pulsed magnetic field generation schemes realizes the effective separation of the AC and DC paths of the magnet load current.The two power supplies are coupled with each other,which makes the control difficult and the compensation effect is not good.This paper proposes a high-stability flat-top magnetic field technology scheme based on magnetic coupling active compensation.This scheme uses the principle of magnetic coupling filtering to make the AC currents which flow through both sides of the magnetic coupling transformer cancel each other out and compensate most of the base in the magnet load.At the same time,a compensation power supply is added to the secondary side of the coupling transformer to further compensate other AC components in the magnet load;the effective separation of the AC and DC paths of the load current can be realized,and the load current can be output with zero ripple in theory.On the basis of theoretical analysis,this paper uses MATLAB Simulink to carry out simulation verification and build a prototype experimental platform.The experimental platform uses a cross-platform integrated measurement control system proposed in this paper.The system makes full use of the advantages of FPGA,ARM,DSP and other control platforms to measure magnetic field information at high speed and high precision,and at the same time control the power supply and store data to display real-time.Experimental results show that the system can realize cross-platform comprehensive measurement and control.At the same time,the prototype experiment achieved a pulsed flattop current waveform with a ripple rate of ±0.80%,which verified the feasibility and correctness of the high-stability flat-top pulsed magnetic field implementation method based on magnetic coupling proposed in this paper.In addition,there are some problems in the process of experimental debugging.These problems are analyzed and solutions are proposed.Finally,this article analyzes and summarizes the relevant experimental results,and puts forward suggestions for the parts that can be improved in the current prototype,which lays the foundation for further improving the stability of the flat-top magnetic field.