Examination of magnetic properties of the multi – Gap amorphous Fe78Si13B9 block cores intended for harmonic filters used in electric power systems

•The innovative technology for the production of amorphous 27-multi-gap cores.•The innovative three-phase amorphous harmonic filters 7,5kW/400 V/50 Hz.•Power losses in the amorphous filter are about 20% lower than those in Fe-Si filter.•For amorphous core the temperature rise after 1 h is lower about 13 °C. There is a permanent demand worldwide for the advanced low-losses soft magnetic materials intended for application in power electronics, including power electronic converters used to process various forms of the electrical energy into such that is best suited for the specific user loads or applications. This paper shows result of investigation of magnetic properties of amorphous multi-gap cores which were used to manufacture a prototype 27-multi-gaps core for the three-phase harmonic filter with a common yoke, with a rated power of 7.5 kW, operating voltage of 400 V and electric power frequency of 50 Hz. The main attention was focused on studying the effect of the chemical composition and core structure on the level of power losses in the core and temperature increase during operation for amorphous material in relation to the polycrystalline Fe-Si steel with 3 wt% Si core despite the low operating frequency of 50 Hz.