Research On Design And Analysis Of Resonant Magnetic Perturbation Coil Power Supply In EAST Tokamak

EAST Resonant Magnetic Perturbation (RMP) coil Power Supply is mainly used to supply special current and voltage for RMP coils, which are used to do research on edge locialized mode and resistive wall mode. To satisfy these requirements, 8 sets of power supplies are needed. The power supply should output maximum 4000 A/450 V,current and voltage latency time less than 0.35 ms and 0.25 ms, voltage ripple less than 2% and bandwidth between DC and 1 kHz. It's necessary to do research on design method of the power supply. Besides, the series-parallel H-bridge structure is adopted for the power supply's inverter, and 384 IGBTs will operate at the same time.As the operation condition of IGBT is special, the junction temperature distribution,failure reason and reliability shoud be also analized. And the dessertation should have a reference for designing similar power supply.Firstly, the design scheme of main circuit for RMP coil Power Supply has been proposed according to the design requirements, which includes the design of switch frequency, equivalent switch frequency, topology structure, RC compensation branch,busbar capacitor and flat-wave inductor. During the design scheme, the relationship of design requirements and design method is concluded. Besides, the design scheme of control system and fault protection is also introduced, and the simulation and test results of the power supply are given to prove the correctness of design scheme.Based on the former design methods of RMP coil power supply, the design scheme of Super Power Supply in DIII-D has been introduced. And the key technology of parallel controller for parallel power supplies has also been proposed. Besides, the optimal method of voltage mode control strategy on the RMP coil power supply now has been proposed.Secondly, in order to analyze the distribution feature of IGBT junction temperature under EAST experiment condition, the functional expression of maximum, minimum and ripple value of junction temperature for pulse and sinusoidal current are obtained by inference. The results show that the current latency time,current frequency,peak value, duty cycle and IGBT's switch frequency can influence the junction temperature, and simulation results based on Matlab can also prove it. To verify the failure mode of IGBT under pulse current condition, finite element method is used to do thermal and mechanical analysis using Worbench, which indicate that the bonding wire and solder layer are the first component to fail.Thirdly, temperature cycling test is used to verify the failure mode of IGBT while operating at EAST experiment conditions, dynamic parameters test under different conditions (driving resistance, collector current, junction temperature and power cycling times) is used to find the suggestion of using IGBT, and power cycling test is used to evaluate the reliability of IGBT.Until now, 8 sets of RMP coil power supply operate very well, and the coils can suppress the edge localized mode. The design methods can provide a reference for the design of similar power supply on ITER or CFETR.