The efficiency of the welder load is higher than that of a thyristor rectifier welder. According to relevant statistics, the demand for DC welding machines in the welding industry of the country in 2008 was 890,000 units. If all the welding machines were used, it could directly save 43,000 tons of copper, 64,000 tons of steel, and save electricity by 680 million KW.H. It saved 566,500 tons of coal, 10.34 million tons of water, and reduced CO2 emissions by 1,144,500 tons. From this we can see that the promotion of welding machines has great economic and social benefits.