Harmonic control and reactive power compensation solutions for electric welding machines

Many enterprises using electric welding machines and spot welding machines have many problems related to electrical energy, such as voltage flicker, current distortion, tripping, transformer overheating, and short lifespan of the welding machines and spot welding machines. What electrical energy problems do welding machines and spot welding machines cause?

Electrical energy quality issues caused by welding machines and spot welding machines
Welding machines and spot welding machines are significant sources of harmonics and reactive power. These machines utilize the high-temperature electric arc generated when the positive and negative poles short-circuit for a moment to melt the solder on the welding rod and the material to be welded, thereby combining the objects being contacted. Their structure is very simple; it is just a high-power transformer. In power distribution systems with extensive use of rapid-changing loads such as welding machines and spot welding machines, there are numerous phenomena such as large amounts of harmonics, rapid changes in reactive power, and unbalanced three-phase loads, which seriously threaten the normal operation of production equipment.

How to address the electrical energy quality issues caused by welding machines and spot welding machines?

Generally speaking, for rapid load changes such as those of electric welding machines and spot welding machines, filtering and power factor compensation can be achieved by using fast compensation/filtration devices based on thyristor switching. However, since the fast compensation/filtration devices based on thyristor switching are themselves affected by harmonics, the currently better approach is to consider using active power filters or compensation devices (such as SVG, APF), which offer better performance in harmonic control and reactive power compensation.

Industrial type active power filters cover various voltage levels from 208V to 1500V. This product is mainly applied in non-linear loads, large AC/DC motors, rectification equipment, rapidly changing loads, etc. For example: rolling mills, electric arc furnaces, medium-frequency furnaces, plastic mixers, mine hoists, and power locomotive power supply systems. Industrial APF is a product specially developed by our company for industrial application environments. The active module is designed in a vertical structure. This structure mode adopts large-capacity IGBT power devices, with the device selection being more than 3 times the effective value, leaving sufficient safety margin. It can work for a long time under large load impact. The module adopts axial flow fans for cooling, with large air volume, sufficient air pressure, and good heat dissipation.