Design Of Positive Negative High Pressure System Control And Its Protection Circuit

With the growing strength of the country,safety issues appear to be particularly important.Therefore,China has increased safety testing in various fields,and required to speed up testing and reduce testing costs.At this time,X-ray detection technology was favored by people.As an X-ray generating device,the high voltage power supply is developing towards high frequency,high stability,small volume and strong antiinterference.In order to ensure the stability and safety of the high-voltage power supply,researchers have studied the control and protection of the high-voltage power supply.Paper introduces the present situation and development trend of high voltage power supply,and the control technology of high voltage power supply and protection technology and so on has carried on the research and analysis,on this basis,designed a model applicable to the positive and negative high voltage power supply system of X-ray detection device control and its protection circuit,including high voltage power supply design in this paper,the main circuit,control circuit and protection circuit,The control circuit and the protection circuit are the key points of the design.The design of the main circuit of the high voltage power supply is mainly aimed at the aspects of voltage inverter boost and filtering and rectifier,among which the voltage doubling rectifier circuit chooses the double voltage doubling rectifier circuit to reduce the excessive power borne by the single voltage doubling rectifier circuit.The control system is mainly composed of adjustable DC output circuit and PI control circuit.The three-terminal voltage regulator module LM7809 and the adjustable resistor are the core components of the adjustable DC output circuit to achieve the function of adjustable voltage.The PI control circuit selects LM358 module,and uses its operational amplifier to form a proportional integral regulation circuit to ensure the stable output of high voltage and beam values.At the same time,a slow start circuit composed of S8050 and other components is added to the control circuit to slow down the regulation speed of PI circuit.The protection circuit is mainly composed of 12 V auxiliary power supply,voltage comparator,SCR and solid-state relay,which can realize the functions of over-voltage,over-current,under-voltage,under-current protection and beam sampling protection.In order to determine the parameters of the components in the circuit,and verify the feasibility of the positive and negative high voltage power supply system control and its protection circuit,MATLAB is used for simulation design.In the case of meeting the feasibility,carry out experimental debugging,check the stability and safety of the power system.After many experiments and debugging,the high voltage power supply system designed in this paper reaches the requirements of tube voltage 0 ～ ±225k V and tube current 0 ～ 10 m A,and realizes the functions of over-voltage,over-current,undervoltage,under-current and beam sampling protection.The control and protection circuit of the power supply system has the characteristics of simple structure,high stability and good safety,and is suitable for X ray detection equipment.