Abstract:

To meet the requirements of micro-arc oxidation, this paper presents a two-stage inverter power supply and introduces its control system. In the proposed control system, a high-performance DSP is used as the control core, and the anterior power and the latter chopper inverter circuits are respectively driven by adjusting two groups of Pulse-Width Modulation （PWM） signals in four lines. The voltage regulation of the power supply is implemented by adopting a limited bipolar control mode in the power converter circuit, and various voltage waveforms are ob- tained by controlling the chopper inverter circuit. Moreover, the proposed control system is of some fault diagnosis and protection functions, such as overcurrent, overvohage-undervoltage, overtemperature and parameter overrun. Experimental results show that this system controls the power supply precisely and steadily and that it improves the adaptability of the power supply.

Key words: micro-arc oxidation, power supply, inverter, control system, chopper