The Study Of High Power Fast Parallel Inverters Supply For Tokamak

Advanced Experimental Superconducting Tokamak(EAST)facility is a kind of magnetic confinement nuclear fusion experimental facility built in China with the ultimate goal of developing clean and infinite nuclear fusion energy.Its successful construction not only makes our country develop rapidly in the field of controlled nuclear fusion,but also provides the foundation of physical and engineering technology for the International Thermonuclear Fusion Test Reactor(ITER).The Tokamak device improves the confinement ability of magnetic field to plasma by increasing the elongation ratio of plasma cross section,but at the same time,it also makes the plasma vertically unstable.A slight disturbance in the vertical direction makes the plasma move along one direction deviating from the equilibrium position,which leads to the failure of discharge.Therefore,active feedback coil is usually added to the vacuum chamber,and the fast control power supply is used to excite it,make a rapidly changing magnetic field to suppress the vertical displacement of plasma.Based on Tokamak device and EAST fast control power supply,this paper puts forward a pre researched items on parallel operation mode of multi-inverters for ITER fast control power supply.In view of the inconsistency of the amplitude,frequency and phase of the output voltage of each branch in parallel when the common DC bus is used,the circulation problem will be caused.In this paper,the circulating current in current mode and voltage mode of the multi-inverters parallel power supply system is analyzed,and a parallel circulating current suppression strategy based on grey prediction model is proposed for the voltage mode.Through three steps,calculating the parameters of each branch,predict the rate of current rise at the next moment of each branch,and adjust the duty cycle of each branch,the circulating current of the multi-inverters parallel power supply system is restrained.The feasibility and validity of the parallel circulating current suppression strategy based on grey prediction model are verified by the simulation of MATLAB and the experiment on the laboratory experimental platform.