Development of high power low ripple plasma spray chopper power supply

Plasma spraying power supply usually adopts thyristor rectifier power supply or inverter power supply, which has problems such as low efficiency and large output current ripple. It is difficult to meet the special requirements of plasma spraying process. A high-power plasma spray chopper power supply was proposed based on an eight-phase interleaved parallel Buck converter in this paper. Firstly, the circuit topology of the chopper power supply was designed. The working principle and the current ripple generation mechanism of the chopper power supply were analyzed. The influence of the number of parallel phases and the duty cycle on the current ripple was clarified. The simulation verification was carried out. Then, based on the requirements of the plasma spraying process for power supply characteristics, a four-phase interleaved parallel module with power of 40 kW was designed. Under the cooperative control of the CAN bus, an 80 kW eight-phase interleaved parallel chopper plasma spraying power supply was formed. Finally, the plasma spraying chopper power supply prototype was built. Spraying experiments were carried out to test the output ripple and efficiency of the power supply. The experimental results show that, compared with the traditional thyristor rectifier power supply and inverter power supply, the current ripple rate of the chopper power supply was reduced by more than 50%, and the power efficiency was up to 94.5%.