Micro-arc oxidation flyback switching current pulse unit and combination of multi-units

Micro-arc oxidation (MAO) is a novel and promising surface modification technique which can significantly enhance wear and corrosion resistance of the metal surface. But energy dissipation of MAO treatment is so large that it has become the most important obstacle of utilizing MAO in many applications. The foremost cause is that the current efficiency of the pulse power supply, which is a key equipment of MAO treatment, is low, and the processing time is long. Because the micro-arc discharge is very complex, the load of power supply has very complex characteristic. Therefore the energy of each pulse couldn´t be effectively adjusted by using square voltage or current pulse power supply, which is the most practical approach. This paper proposes a flyback switching current pulse unit which is capable of outputting the spike current pulse. The coupled inductor is used to store and transfer energy, the single pulse energy could be regulated by setting the peak current of primary windings of the inductor. This unit can be used to constitute power supplies with different forms by parallel connection, interleaving parallel connection, anti-parallel connection. Experimental results show that the power consumption of the flyback switching current pulse power supply decreases remarkably comparing with the square current pulse power supply and the processing time of former is shorter than latter. Experimental result of parallel connection units are given to verify the effectiveness.