Development Of The Micro-arc Oxidation Power Source Control System Based On DSPIC30F4011

Micro-arc oxidation is a new surface treatment technique applied to valve metalsand their alloys to form the ceramic membrane on the surface with a high-qualityperformance. It has a wide application in the aviation, aerospace, mechanical,electronic and biological materials etc. as the resistance to abrasion, corrosionresistance and insulation properties of the metals forming the protective film aregreatly improved. At present, the organizational structure of ceramic coating andperformance analysis aspects were mainly studied except the power supply ofmicro-arc oxidation. Based on the research of micro-arc oxidation output waveformand load characteristics, the micro-arc oxidation power supply with theDSPIC30F4011as the core of micro-arc oxidation power supply control system wasdeveloped. The output cross-flow mode and constant voltage mode can be selected,but also the power-supply can produce four kinds of output mode, which were DC,pulse with discharge circuit, unipolar pulse and bipolar pulse. Besides, the pulseamplitude, frequency and duty cycle had a very wide adjustment range, the processcontrol for micro-arc oxidation was achieved. The main research work is as follows:The power supply includes main circuit and power control system. The maincircuit includes rectifier circuit, filter circuit, chopper circuit, the discharge circuitand protection circuit. Rectifier circuit and filter circuit can control the output pulseamplitude of positive and negative. When discharge circuit was used in the outputpulse mode, storage electrical energy of the load capacitance-loading was unloadedtemporarily. The output mode, output pulse frequency and duty cycle were controlledthrough the chopper control. The Protection circuit is mainly used to protect thepower devices to be safe and reliable.Power control system consists of two parts: power master control system andhuman-computer interface system. The DSPIC30F4011DSC(digital signal controller)was serving as the core of control system, which can collect the voltage and currentsignals and the parameters set in manual mode, the trigger pulse of SCR(siliconcontrolled rectifier) and drive pulse of IGBT(insulated gate bipolar transistor) weregenerated to monitor the working status. The AT89C52MCU was serving as the coreof human-computer interface systems. Through the chip use of HD7279A, the presetof power parameters, power output mode and the working methods were realized. During the process of the micro-arc oxidation, power supply parameters, time andwork status can be displayed in real-time. The data and command can be exchangedusing serial interface communication between the two control systems.