| HT-6M is a small Tokamak device which was designed and developed by the Institute of Plasma Physics.In response to the Belt and Road cooperation initiative put forward by the state,the Institute of Plasma Physics has signed the agreement with the Thai Institute of Nuclear Technology which is the HT-6M Tokamak device is donated and helped them complete the subsystem design.The power supply is one of the core subsystems of the project.According to the project requirements,the power supply for HT-6M Tokamak is designed and developed in this paper,and the key technologies are studied in the power supply.To meet the demand of plasma discharge,The transient processes of all pulse power supplies are studied in detail and the power parameters are designed.At the same time,the toroidal field power supply scheme is improved.According to the analysis of the transient process,the implementation scheme of the power key device is designed.The research focuses on the design of high-power fully controlled solid-state IGCT switch is studied and designed,which solves the problems of turn-off overvoltage,dynamic voltage-sharing and current-sharing,and successfully realizes the switching off under the condition of 6.8 kV/17 kA.It is currently the highest operating power fully controlled solid-state switch in the fusion field.A new strong trigger circuit for pulse thyristor switch is designed,which has the advantages of large output current peak value and fast response speed,and can ensure the fast and reliable conduction of thyristor switch.The several short-circuit processes are studied theoretically,and the advantages and disadvantages of different protection methods are compared.According to the requirements of short-circuit current and temperature rise of damping inductor,the structure and parameters of damping inductor are designed to ensure the safety of power supply and personnel.It is the most powerful fully controlled solid-state switch in the fusion field at present.Finally,the test of key device and power supply is completed.Due to the uncontrollable output current of the pulse power supply,real-time control of plasma current cannot be achieved,a set of negative feedback field power supply based on interleaving Buck circuit is designed.Firstly,to avoid damage to core components caused by overcurrent and overvoltage during startup,the mechanism of overcurrent and overvoltage is studied,the soft start circuit is designed,The design range of soft start resistance is given.Then,in order to ensure that the output current is continuous and meets technical requirements,Multiple operating conditions are analyzed mathematically,and the current curve is provided.The parameters are designed.the overall development and test of the power supply are completed.The output response can meet the operation requirements of the HT-6M device.The charging power supply is the core unit of the pulse power supply,which directly determines the accuracy of the output voltage and working cycle.the series resonant charging power supply is finally selected after analyzing and comparing different kinds of charging power supplies.Then,the working mechanism and transient process are analyzed in detail mathematically,and the voltage and current working curves and calculation methods under each transient process were provided.The design principles of resonance parameters were obtained.Finally,the development and testing of the charging power supply are completed,and the experimental results are highly consistent with the theoretical analysis.There are voltage-sharing and heating issues during the operation of pulse thyristors.Firstly,the equivalent circuit of static voltage-sharing is established and analyzed.The mathematical model between static voltage sharing resistance and voltage-sharing coefficient is provided.The static voltage equalizing resistance parameters are designed to ensure that the voltage equalizing coefficient is greater than 0.8.Then,the mathematical model of thyristor opening and RC parallel equivalent circuit are established,and the expressions of thyristor terminal voltage and buffer circuit current are obtained by mathematical analysis.The influence of buffer parameters is analyzed,and the parameters of buffer capacitance and buffer resistance are designed.For the temperature rise and lifetime of the thyristor,the structure of thyristors is analyzed,the thermal circuit problem is converted into a circuit problem,and the Foster network model of thyristor transient thermal impedance is established.By fitting various types of transient thermal impedance curves and on-state voltammetry curves,the temperature rise is calculated according to the Foster network model.It can provide a basis for device selection. |
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