Research And Design Of Digital Inverter Resistance Welding Machine

With the people's increasing demands for the welding control and welding quality,as well as the continuous development of the computer control technology and high power switching device IGBT,the Digital Inverter Resistance Welding Machine has been widely concerned depending on it's three-phase load balancing,fast dynamic response,high welding quality,convenience and high efficiency.In this thesis,the working process and control mode of the Inverter Welding Machine are deeply analyzed.At last,we design the new Digital Inverter Resistance Welding Machine.Firstly,the thesis introduces the working process,welding factors,topology,working mode of the Digital Inverter Resistance Welding Machine,and uses Matlab/Simulink simulation software to simulate the welding mode of constant voltage,constant current,and constant power.Secondly,the thesis introduces the main circuit and control circuit of the Digital Inverter Resistance Welding Machine in details,and designs the main circuit and control circuit according to the design requirements.The main circuit includes input protection and anti-jamming,three phase input rectifier filter circuit,surge voltage suppression circuit,full-bridge inverter circuit,IGBT buffer protection,transformer circuit and secondary rectifier circuit.This paper introduces working process of the each circuit and the calculation of the circuit parameters,the selection of the device and buffer protection circuit.As the core controller of Digital Inverter Resistance Welding Machine,the main circuit controls and monitors the normal operation of the system.The thesis introduces the overall structure of the control system,and analyzes each part of the circuit.The control system includes the design of MCU minimum system,man-machine interface,rectifier output current and welding current detection,over-current fault protection,PWM interlock circuit and IGBT driving circuit.In the thesis,the flow charts of the software are designed according to the constant voltage,constant current and constant power working mode of the Digital Inverter Resistance Welding Machine.Finally,the thesis analyzes the debugging results and experimental waveforms of each part of the circuit,and test the stability and reliability of the whole machine.According to the problems encountered in the test process analysis,to make the relevant circuit improvement and algorithm improvement.The test results are basically in accordance with the design parameter and requirements.At the end of this paper,a conclusion and some deficiencies and improvements are put forward on the basis of this thesis.