Research On Control Technology Of Tokamak Magnetic Compression Plasma Power Supply

While regarded as the most ideal way for human beings to solve the ultimate energy problem,controllable magnetic confinement nuclear fusion has a long way to go to achieve plasma ignition and self sustained combustion.The adiabatic magnetic compression(MC)heating is an effective way to improve the parameters of magnetically confined plasma.The paper studied the influence of magnetic compression on plasma confinement performance by analyzing the plasma discharge parameters of Tokamak device and the structure of coil power supply system required to achieve magnetic compression.The paper focused on the steady-state analysis,control,simulation analysis and experimental verification of power converter.First of all,the paper verified that there is a weak magnetic compression process in Tokamak plasma discharge,and concluded that magnetic compression can improve the magnetic confinement performance of plasma by collecting and analyzing the plasma discharge data of EAST#43888 shot.Meanwhile,it established the basic equations of plasma parameters and magnetic compression ratio,and provided three possible compression methods and two-step compression methods,as well as determined the scheme and control strategy of Tokamak magnetic compression plasma.On the power scheme,the paper determined the magnetic compression power system(MCPS)with a modular design,and provided the topology of the traditional fusion power supply and the magnetic compression plasma power supply using SiC high-voltage power devices respectively.In addition,the power module N+1 redundant IPOP structure is adopted.The power module adopted the two-stage topology,former three-phase full control rectifier and latter DC-DC converter.The paper provided the two-stage starting scheme of the power module with the minimum current response,which realized the dynamic balance of the primary and secondary voltage of the transformer and suppresses the inrush current.Secondly,the paper introduced the topology of the phase-shift full-bridge series resonance converter(PSFB-SRC)of the power module.The three working modes of SRC with variable phase shift angle and conditions for ZVS realization were analyzed in depth.The correctness of the PSFB-SRC model analysis results is verified by adopting methods such as simulation and experiment.In the term of the control of the converter,it adopted the PSFB DPWM method with STM32 microcontroller as the core of controller.The double closed-loop P1 regulation control is adopted in the control method.The digital compensator of the converter was designed by using the method of MATLAB loop sweep.Meanwhile,the control strategy is verified by using the the experiment of building a small power PSFB-SRC prototype.Finally,the paper described the advantages and drawbacks of the traditional single-cycle control strategy of the VIENNA PFC rectifier of the power module.An improved single-cycle control strategy is proposed to adjust the input current distortion of light load.To suppress the deviation of neutral point potential on the DC side by injecting third harmonic.Meanwhile,the control strategy is verified by using the simulation and small power prototype experiment,and it is concluded that it can greatly improve the VIENNA rectifier input current harmonic suppression and output neutral point potential balance.