Design And Research Of Portable High Voltage Generator

X-rays have had a profound impact on scientific development and technological advancements,and are widely used in safety inspections,medical imaging,semiconductor internal inspection and non-destructive testing.At present,most highvoltage generators use 220 V AC for power supply,and their working environment is inseparable from the power supply equipment,but in special applications such as medical and security inspection,offline small-volume,integrated high-voltage generators are required.In this context,this paper designs a portable high-voltage generator for X-ray tubes with a lithium battery power input voltage of 24 V,an output voltage of 30 k V to 120 k V,and a tube current of 0.2m A to 1m A.Portable high voltage generator system composition mainly includes high voltage generator main circuit,filament circuit,control circuit and X-ray tube,in which high frequency high voltage transformer,multiplier rectifier circuit and high voltage sampling circuit is the focus of the study,the research content is as follows.(1)For the problem that the high output voltage of high-frequency high-voltage transformer(6k V)cannot be directly experimentally verified,this paper uses Maxwell software to design,model and simulate,and verifies the correctness of the design.Based on the theoretical models of output voltage ripple and voltage drop of CW(Cockcroft-Walton)multiplier rectifier circuit and single-phase bi-directional rectifier circuit,this paper designs a positive and negative bi-directional multiplier rectifier circuit with small ripple,low output voltage drop and low insulation degree.Finally,a comparison experiment is conducted with a large tank and a prototype to verify the correctness of the parasitic parameter model.(2)To address the problem that the internal parasitic parameters of the highvoltage resistor in the sampling circuit cause a large impact on the sampling voltage at the moment of starting the high-voltage generator,this paper analyzes the influence of the internal parasitic parameters of the high-voltage resistor on the sampling voltage of the low-voltage arm,designs a new resistive parallel sampling circuit based on the zero-state response model of the parasitic parameters,and analyzes and simulates it to verify the advantages of the resistive parallel sampling circuit.In summary,this paper built an experimental prototype of portable high-voltage generator,and the experimental output voltage reached 30 k V～120k V and the tube current reached 0.2m A～1m A,and the experimental results verified the correctness of the theory and simulation.Meanwhile,under the same input and output conditions,the efficiency of the prototype was found to be 6.1% higher than the efficiency of the foreign equipment by comparing the equipment of VJ and the prototype,which meets the design requirements.