Research Of Embedded Control System For Micro-arc Oxidation Power Supply

Micro-arc oxidation is a surface treatment technology using the electrolyte and micro-arc to form a high resistance state, corrosion resistance, wear resistance ceramic oxide film on the surface of Al, Mg and other nonferrous metals and their alloys. This technology can significantly improve the metal surface properties and has been appilcated in the fields of aviation, aerospace, machinery, electronics and biological materials fields. At present, many of the micro-arc oxidation power supply used microcontroller as the core of the control system, which had some problems such as the processing speed and computing capacity was limited, the man-machine interface was complex, compatibility was not good and so on. And there was no operating system transplant, which could support network communications. Therefore, it is very necessary to introduce embedded technologys in the micro-arc oxidation power supply, and make it develop towards digitization, intelligence and networking.This paper has designed a DSP+ARM dual core architecture embedded control systems which based on the traditional two-stage inverter main circuit structure micro-arc oxidation power supply. The control of micro-arc oxdation process is based on TMS320F28335, and can accomplish the functions of voltage and current signal acquisition, waveform driving and fault detection, so that the system can respond to the load rapid changes and achieve stability control. The communication between DSP and ARM is through SPI interface. This paper transplanted embedded Linux operating systems on S3C2440 microprocessor and complete driver development and application programming. A friendly touch screen human computer interaction based on Qt GUI development realized the functions of parameter setting, real time data display, graphics rendering and U disk export of the experimental results. In addition, by transplanting embedded Web server the function of remote monitoring is achieved.Based on the micro-arc oxidation power supply embedded control systems, this paper completed aluminum alloy micro-arc oxidation treatment by three modes of DC, unipolar pulse and variable polarity pulse. As the result shows, the embedded control system which consisted of high performance controller and stable operating system could respond quickly and accurately control to load in different modes. And it also achieved a good human computer interaction and remote monitoring function.