Design Of Micro-arc Oxidation Pulse Power Supply Based On DSP

Our magnesium metal reserves and production rank first in the world, but the consumption of magnesium metal in China is a serious shortage. Because it has good damping and electromagnetic shielding performance, magnesium has become one of the preferred materials for modern automobile, electronics, communication and other industries. However, its corrosion, easy wear, low hardness and other issues are also soon highlighted, a variety of surface treatment technology have emerged for solving these problems.Micro-arc Oxidation (MAO), also called Micro-plasma oxidation (MPO), which is a new technology for metal surface treatment in recent years. Micro-arc oxidation ceramic membrane generated by high temperature resistance, corrosion resistance, wear resistance, excellent insulation properties, has a broad application prospect in the fields of aerospace, aviation, automotive, electronics, shipbuilding and other fields. The power supply is an important factor to restrict the development of MAO technology. The traditional power has the problem of large body size, control precision and low working efficiency. So, a micro arc oxidation pulse power source based on DSP was designed for the process of micro arc oxidation in this paper.The pulse power supply is the key step in the process of micro arc oxidation, directly affecting the formation and characteristics of the ceramic layer. This paper designed a high-power, variable waveform, frequency and duty cycle parameters controllable pulse power based on Digital Signal Processor (DSP). In the introduction, the parameters of the experimental results are analyzed,and the appropriate parameters are selected. The power supply main circuit adopts EMI filter circuit, the rectifier circuit, the DC-DC converter and the IGBT chopper inverter circuit. The digital signal processor using TMS320F2812, the ARM man-machine interface using LPC2119, DSP control board can communicate with ARM HMI through RS485 communication interface circuit for real-time in the power circuit. Using the TMS320F2812 DSP control chip as the core, the paper completes the IGBT drive circuit, current and voltage sampling circuit, voltage fault protection circuit, overheat detection circuit and power supply circuit of control system design. Taking TMS320F2812 as the core, this paper completed the software design of the control process including the main program operation, A/D sampling, PWM control, PID control and so on.This paper has finished the production of each circuit board, and the circuit of the assembly. Through the power supply system hardware platform for debugging, and analyze the results. The subject completed the power structure optimization and control precision, and the output waveform is good.