| In modern scientific research, technology of pulse magnetic field has gained world-wide attention, and many breakthroughs in science and technology projects are carried out under conditions of pulse high magnetic field. Wuhan National High Magnetic Field Center mainly consists of the pulse power supply, pulse magnets and experimental stations. The power supply system is an important part of the whole experimental device, and the quality of the output pulse power determines the strength and waveform of pulse high magnetic field. The power supply of pulse high magnetic field should have some features like high-power, high-energy and wave controllability.This paper studies the construction of power supply system of pulse generator, and the method of decreasing the coefficient of the magnet current ripple when the magnets are energized by the impulse power source. Firstly, in order to reduce the ripple by controlling the rectifier system, the twelve pulse rectifier for rectification is chosen. The theoretical calculations of the equipment containing rectification switchgear, rectifier consisting of thyristors, balance electric reactor and load magnets are done, and then the specific parameters are selected. The study focuses on the feedback control system of rectifier, and the control system with both characteristics of being real-time and high accuracy which can effectively control the waveform of magnet and reduce the ripple.In order to obtain the waveform of flat long-pulse magnetic field with higher stability and a smaller coefficient of ripple to meet some stringent requirements of scientific experiments on the rate of flat-topped waveform of magnetic field, the design of filter coefficient based on the control of rectifier system is proposed in this paper. Based on the analysis of the existing filtering scheme, the effect of the magnet current ripple decreases on DC sides of both the passive filter and active filter reduces are studied, the advantages and disadvantages of the two filtering methods are discussed, and a theoretical analysis of reducing the ripple of pulse magnetic field is done, and an idea for the establishment of the wave filter of power system is designed.We use the MATLAB simulation software to do the modeling and simulation of the rectifier system and filtering system. Simulation results show that the method of controlling the rectifier system is very successful. The pulse generator power supply system can generate a flat pulse wave with strength of 50.7T,flat-topped pulse width of 100ms and current ripple factor of less than 1%. The filter system realizes the scheme of passive filter with a single coil, making the ripple coefficient of current become 100ppm. Finally, considering the practical application, an actual scheme of filtering which lays a good foundation for further improving the pulse generator power supply system is proposed. |
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