Development Of Pulse Lithotripsy Resonant Charging Power Supply

Pulse power is the energy stored in a period of time and then released in a very short time,so as to obtain a large instantaneous power.With the development of science and technology,pulse power technology has been gradually extended from the initial military application to medical treatment,mining,rail transit,biology and other fields.Among them,rock breaking has a great prospect for development.Compared with traditional mechanical crushed stone,pulse crushed stone has the characteristics of cleanness,efficiency,low damage and simple control.The development of charging power supply for hv capacitor is very important for the whole equipment.This paper focuses on the development of high voltage and high power series resonant charging power supply in pulse gravel device.Firstly,the basic circuit and principle of pulse gravel are introduced,and the difficulties of pulse power supply are analyzed.The experiment then introduced the basic principle of the charging power supply,using LC series resonance in the mode of intermittent current operation,so as to charge the constant current and work in the soft switch state.Moreover,the various working processes of the charging power supply are analyzed,and the expressions of resonant current and charging voltage are obtained for convenient analysis.The terminal pulse of pulse crushed stone is extremely large.In order to prevent the electromagnetic interference generated by the pulse and the high voltage harm to personal safety and equipment,this experiment adopts the computer interface control and connects the PLC control equipment through the optical fiber.As the controller,PLC realizes the work flow control,state indication,parameter setting,software protection and other functions of power supply.The human-computer interaction interface is made by labview.This paper presents the main circuit design of series resonant power supply,including circuit topology,component selection and simulation analysis.At the same time,the control circuit design,including MC33067 PWM generation circuit,IGBT drive circuit,A/D,D/A conversion circuit,overvoltage,overcurrent alarm stop charging circuit.The hardware and software monitor and warn the power supply at the same time,so that the fault tolerance rate is higher and the operation management is more convenient.In this paper,t-type protection is designed and the experiment and calculation are carried out.The minimum resistance is adopted to ensure the normal operation of rectifier silicon reactor and reduce the loss to the minimum.The thyristor is designed to switch on and off the power supply,so that the thyristor can work normally under continuous high voltage and large current switch effectively.Finally,a 40 kW and 20 kV series resonant charging power supply was completed and used in the pulse gravel device in the laboratory.The device ran well for 48 hours continuously.