All-digital Welding Power Source Control System

This paper firstly introduces the shortcomings of traditional analogue control circuit and microprocessor which have become the bottleneck for further promotion of the welding inverter power. According to the characteristics of digital signal processing, the digitalization of welding inverter and its future development on the basis of illumination of the DSP's basic characteristics are introduced. At the same time aiming at current research status, the paper discusses the necessary of this investigation.Digital welding includes digitalization of main circuit, control circuit and manmachine interaction system. Main circuit and control circuit are the core of digital welding power source. Man_machine interaction system is the outer behavior of digital welding power source. The system is operator_oriented. The operator inputs messages into computer, and observes real_time process parameter. It has advantage in terms of stability, reliability and consistency and so on.The paper focuses on component part and control principle of man_machine interaction system of digital welding power source. Liquid Crystal Display(LCD), Keyboard and Communication with Personal Computer(PC) are designed and analyzed respectively. Furthermore, the software and hardware aspects are also addressed.Man_machine interaction system finishs tasks to setup and modify welding process parameters and to display information on welding site.(l) LCD part: The design is applied CM160 X 128 LCD module which includes T6963C controller.The paper illuminates used method and programmed method.(2) Keyboard part: Keyboard includes sixteen keys which are "0-9", "enter", "up", "down", "cancel", "setup", "pause".The system chooses special display drive module HD7279A.(3) Communication with PC: The design is applied RS₄85 interface.The paper illuminates development, application and classification of complex programmable Logic Device(CPLD).Software development circumstance and software descript language(VHDL) of CPLD are introduced in details in the paper.At last, In virtue of advantages and disadvantages of MCU and CPLD, the design of MCU+CPLD and improved advices are put forward in allusion, and it will make a found ground for tomorrow's research of digital welding power.