Research Of Compensation Power Supply For Flat-topped Pulsed Magnetic Field Based On Parameter Adjustable Coupled-inductor Filter

With the improvement of traditional science,making new breakthroughs under routine experimental conditions becomes more and more difficult.As extreme experimental conditions,high magnetic fields play an important role in the research of many scientific fields.As frontier science like NMR and Terahertz sources,magnetic field strength and stability are both required.Therefore,the concept of a flat-topped pulsed strong magnetic field was proposed.Due to its high field strength and good stability,many scholars pay attention to this area.There are mainly two steps,rough-adjustment and precise-adjustment to achieve a pulsed flat-topped magnetic field.Main power is applied to pulsed magnet first,making the magnetic field enhanced continuously.When the field strength reaches the target value,the compensation power supply works.With control strategies,the compensation power supply filter out the ripples created by main power,making flat-topped magnetic field generated.So we can say,the compensation power supply is the key of pulsed flat-topped magnetic field.This paper use pulse generator as main power and build a prototype of compensation power to create flat-topped magnetic field.After a comparative analysis,the shunt compensation method was selected,and the phase-shifted full-bridge was used as its topology.Then we point out that the opening and closing of switches in the compensation power supply generate ripple,which will affect the stability of the flat-top magnetic field.Coupled-inductor filter is used to solve this problem.This circuit makes use of the principle of reverse current on the sides of transformer to offset the output ripples,which can achieve zero-ripple theoretically.Adjustable reactor is also used in this circuit,making elements' parameters better matched.Then we build a small experimental platform to prove the correctness and feasibility of the theory,Finally,we summarize the results of experiment and analyze the places which can still be improved,laying a foundation for improving the performance of the compensation power supply.