Design And Realization Of Pulse Power Supply System For Pulsed High Magnetic Field

The high magnetic field is one of the important and basic research tools in condensed matter physics, materials science and other research areas. Therefore, the pulsed high magnetic field facility is vigorously developed worldwide as an effective way to obtain high magnetic field. The pulsed power supply is one of the core elements of the high magnetic field facility. The pulsed magnet is energized by the pulsed power supply, which directly determines the strength, waveform and quality of the high magnetic field. Considering the advantages and disadvantages of various pulsed magnetic field power supplies, and the present conditions and planning of the Wuhan National High Magnetic Field Center in Huazhong University of Science and Technology, the pulsed capacitor bank and the pulsed generator are selected as the high magnetic field power supply. This paper studies the design and realization of these two kinds of pulsed power supply for high magnetic field.According to the single module and multi-module two operation modes of pulsed capacitor bank power supply, the relation of the main parameters of pulsed capacitor bank power supply and the strength, waveform of magnetic field is analyzed, and the overall design of the pulsed capacitor bank power supply system is proposed. According to the design requirements of the main components of the pulsed capacitor bank power supply module, the specific design of the pulsed capacitor with the damping inductor, the discharge switch with the protection inductor, crowbar branch is present.The pulsed capacitor bank power supply system testing includes main components testing and power supply module testing, wherein the module impedance test builds the more precise model of the pulsed capacitor bank power supply module for subsequent analysis. The circuit with the parasitic capacitance of the cable is analyzed for the transient overvoltage occurred at the moment of discharge, and a RC snubber circuit branch is designed to absorb the transient overvoltage.This paper analyses the demand of pulsed generator system and pulsed magnet, and determined the DC parameters of the pulse rectifier system, then the overall design of the pulsed rectifier system is proposed. According to the characteristics of the pulsed rectifier system, the crowbar branch consisted of a thyristor crowbar branch and a mechanical switch is designed as the protection of DC fault. At last, the overall design of the pulsed rectifier system is verified through the simulation with the planning pulsed magnet.With the analysis of the monocoil magnet circuit and flat-top magnetic field ripple, the system configuration principles about AC voltage, export reactor and line impedance is proposed for the magnetic field ripple minimization. According to the analysis of dual-coil magnet circuit, three control strategies, full current flat-top, no current flat-top, semi-current flat-top are proposed. The optimal control strategy and the system configuration, which are put forward for the magnetic field ripple minimization, and verified by experiment. According to the analysis of the magnetic field ripple of two topologies,12-pulse rectifier in series and24-pulse rectifier in series, the optimal firing angle distribution curve, under the asymmetrical trigger angle mode, is obtained.