| The processing of nozzle holes of diesel fuel injector is a kind of micro-hole processing,and its processing quality directly influence the fuel injection and atomization quality of highpressure fuel common rail system.Since the micro-EDM of RC pulse power supply is easy to control the power discharge energy and can realize micro-energy pulse processing,this process is often used in the processing of micro-holes in the pulse power supply industry.The controllable RC pulse power supply for the processing of nozzle holes of diesel injectors is studied in this paper,and the specific research contents are as follows:By analyzing the working principle and working characteristics of the controllable RC pulse power supply,the overall frame design of the pulse power supply and the RC topology structure design were completed,the pulse discharge energy control scheme and the main circuit design scheme were formulated,and the main circuit design of the pulse power supply was completed.The multisim circuit simulation software is used to simulate and analyze the relevant nodes of the designed pulse power supply main circuit.The design of the pulse power supply related hardware working circuit with stm32f103zet6 as the control center has been completed.It mainly includes the design of the main circuit of the pulse power supply,the capacitor bank circuit and the gap detection circuit,as well as the determination of the parameters of the related components.The drive control of the power switch tube is taken as the center,and the control of the circuit structure is added to realize the pulse energy control.The gap detection circuit is used to feedback the machining gap status.By analyzing the machining gap detection mechanism and closed-loop control theory,the control model of the actuator of the gap detection control system was completed and simulated.Matlab/simulink was used to establish the model of the stepper motor control system,and the stepper motor control method was studied by using the current subdivision control and the speed curve control method.The simulation results show that the subdivision drive control can refine the step angle according to the specified number of subdivisions and improve the resolution of the motor operation;the stability,high-speed response characteristics and positioning accuracy of the motor during operation can be improved in the parabolic speed curve control.Finally,the corresponding stepper motor drive control mode is selected according to different application scenarios.With stm32f103zet6 as the central controller,the design of the software control system of the pulse power supply has been completed,including the design of the main control program,the gap function program,the stepper motor and electrode control program,and the upper computer interaction software.Finally,PCB design and circuit board welding were carried out for the designed pulse power circuit,the physical development of the pulse power supply was completed,and the relevant nodes of the circuit was tested and analyzed with an oscilloscope.The research shows that the pulsed power supply designed in this paper has stable working process,good discharge pulse energy control effect,and can meet the micro-energy discharge requirements of high frequency and narrow pulse width. |
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