High-frequency power sources

In resistance welding, high-frequency power sources are inverters in which the DC link is clocked at a frequency greater than 1000 Hz, usually 10 or 20 kHz. The welding transformers then operate with this generated alternating voltage at 10 or 20 kHz. Subsequently, rectification takes place in the transformer or in the diode package and a rectified high-frequency voltage is available at the welding point.

As with the medium-frequency systems, the high-frequency inverter (HFI) also consists of an input rectification of the mains voltage, a DC link and an IGBT bridge circuit that provides the high-frequency voltage to supply the welding transformer. The monitoring and control electronics are also part of the overall system.

Here, Harms & Wende offers not only the control series known from medium-frequency technology (Sinius, Filius and Genius) but also additional special systems (iSpot). The high-frequency power sources are mainly used in the field of small part joining (micro welding). Besides the shorter time base of 0.1 ms, the very constant and stable direct current are the advantages of this technology.

The even higher dynamics of the high-frequency power sources also offer advantages for welding in applications in the mechanical engineering and automotive sectors.