The development of a modern heat treatment unit with embedded control ensuring minimal retroactive effects on the supply network

Within the frame of research, our team realized a comprehensive development for modernisation of the heat treatment unit “RETEP” in cooperation with the company Svarservis Group. A heat treatment unit is a device used mainly to heat welds in mechanical engineering, energetics and during fabrication of technological units but also to a lot of other applications. This article describes the development of control circuits of power solid-state relays of the heat source including algorithms of control. The implementation of algorithms of two ways of controlling was done - phase control and full-wave control - as well as their comparison. A new switching algorithm was developed for the method of full-wave control, which ensures the required equal distribution of performance with load. The whole question was also dealt with to limit at the most the negative influences on the supply network. The negative influence of harmonic components was nearly completely eliminated in the newly developed algorithm for full-wave control. That is why it is also possible to use this modern newly developed heat source in public distribution network in case the compatibility levels required by the standards are observed. The validity of the whole solution was proved by experimental measuring.