Design Of Kicker High Voltage Charging Power Supply

A high-voltage and high-power Kicker charging power supply was proposed for the High Intensity Heavy-ion Accelerator Facility(HIAF)to meet the requirements of high-frequency injection and extraction of beam.The author investigated the design of high-voltage charging power supply,compared different high-voltage charging methods,and chose the LC series resonant constant current charging scheme finally.According to the relationship between the switching frequency and the resonant frequency,the LC series resonance has three different working modes.After analysis and comparison,the discontinuous current mode was selected,in which the charging power supply can work in soft-switching state.In this paper,the theoretical analysis of the working principle in the discontinuous current mode had been carried out,and the calculation formulas of resonant current,resonant voltage,average charging current and load voltage were derived.The variation law and the influence parameters of the values were expounded.Design specifications of the prototype of the charging power supply were proposed based on the requirements of the HIAF project.Design of the main circuit and the control protection circuit of the prototype are discussed in this paper.The design and selection of the components in three-phase rectification and filtering,resonant inverter,high-frequency transformer and high-voltage rectification are introduced in detail.In addition,the realization of soft start function of power supply,the design of heat dissipation and whole structure in the prototype are also introduced.The design of high frequency transformer is critical for the prototype of the charging power supply.By comparing different core materials and core structures,the ferrite material with CC structure had been chosen as the core of the transformer.The windowing area method is used to calculate the number of turns on the primary and secondary sides of the transformer.Combined with the insulation design of the transformer and the control of the distributed parameters,a high-frequency transformer that meets the design requirements was customized.The control circuit is developed based on Altera’s FPGA.The design of digital power controller was carried out on SOPC platform based on NiosII.The driver chip of driving circuit is 2SC0435T2G1 which developed by Swiss CONCEPT company.The feedback loop uses a LEM current sensor and a 2500:1 resistor divider to acquire the resonant current signal and the load voltage signal.Through the high precision 18 bit ADC,the sampling signal is compared with the setting values written in the controller to protect the power supply from over-voltage and over-current.Finally,a prototype has been built according to the design.Repeated charging test and soft-switching verification test were carried out.The test results show that the charging voltage of the prototype is adjustable from 0 to 20 kV,and the charging voltage error is less than 2%.The prototype can work in soft-switching state and meet the design requirements of Kicker system in HIAF project.