The work is devoted to solving the problems of creating energy-efficient power supplies for welding. It is worth to note that energy efficiency is determined not only by the energy conversion efficiency itself, but also by the electromagnetic compatibility of the power supply, its ability to easily ignite and stabilize the welding arc, good weight and size characteristics, the possibility of application of modern control methods that provide control over the process of arc burning, over the transfer of the electrode metal and so on.
Due to the development of the high performance inverter-type power supplies with, various technologies for ensuring controlled transfer of electrode metal, reduction of spattering, etc., appeared. However, the problem of electromagnetic compatibility of inverter welding power supplies with the network often goes unnoticed. Inverter welding supplies are powerful generators of high-order current harmonics, which leads to a deterioration of the operation efficiency of the electrical network, increasing energy losses in it, inducing distortion of the voltage waveform. Moreover, the nonconformance of most inverter-type power supplies with modern electromagnetic compatibility standards does not allow to organize their export.
Therefore, the main attention in the work is paid to the development of such approaches to the creation of inverter-type power supplies for welding, which, while maintaining the quality of the implementation of the technological process of welding, surfacing, etc. associated processes, will allow to eliminate or partially compensate the negative effects associated with their work in the electrical network, and ensure compliance with the requirements of the electromagnetic compatibility standards.
In accordance with this goal, the main task of present work is the development of the principles of creating such welding power supplies, which, in addition to good technical, weight and size parameters, meet the requirements of current electromagnetic compatibility standards.
The relevance of the work is also determined by the fact that in Ukraine, standards that limit the emission of harmonic currents by technical means have been put in place (DSTU IEC 60974-10: 2007, DSTU IEC 61000-3-2: 2004, DSTU IEC 60974-10:2007). In 2014, a standard for electromagnetic compatibility for equipment with a current of 16 to 75 A per phase was introduced (DSTU EN 61000-3-12: 2014). The vast majority of welding power supplies fall into this category of equipment.
Several approaches are proposed for solving the aforementioned problems: 1 - development of active rectifiers for inverter welding supplies with double energy conversion (AC/DC/AC); 2 - development of welding inverters with partial power factor correction;
3 - development of direct conversion power supplies for welding; 4 - development of welding power supplies with integrated functions of parallel active power filters of high-order harmonics, which can partially compensate the negative effects of operation of other equipment with a nonlinear input resistance in the electrical network; 5 - modification of existing welding equipment with low-frequency transformers by means of the development of control blocks and systems that ensure the effective formation of the required output characteristics; 6 - development of universal devices for excitation and stabilization of welding arc burning, suitable for work with existing low-frequency, and with inverter-type welding power supplies.
