Dissertation submitted in fulfillment of the requirements for the degree of doctor of
technical sciences, specialty 05.09.03 – Electrotechnical complexes and systems (141 –
Power engineering, electrical engineering and electromechanics) – Kremenchuk Mykhailo
Ostrogradskiy National University Ministry of Education and Science of Ukraine, Kremenchuk, 2019.
The dissertation deals with fundamental research in the field of studying of complex
electrotechnical processes in electrotechnological installations of resistance welding, which
consist of interconnected complex of electrotechnical devices, control systems of them,
means of improving energy efficiency and productivity, their mathematical and physical
model, exploring the possibility of improving parameters and characteristics to ensure their
effective work. The dissertation deals with fundamental research in the field of development of power systems of welding equipment, which will have high performance, energy
efficiency and electromagnetic compatibility with the electrical grid.
In the dissertation, the problem of creating highly efficient power systems for resistance welding is considered from two sides: from the need to ensure the electromagnetic
compatibility of power supplies for resistance welding machines with an electrical network;
from the need to ensure consistently high quality of welded joints in presence of external
disturbances.
The use of the developed power supplies for resistance welding machines will improve both the efficiency of these sources and the energy efficiency of the electrical networks to which they are connected. The conformity of power supplies of resistance welding machines to the emission of higher current harmonics, which are regulated by international standards, is necessary when promoting them to world markets.
In accordance with this, the goal and objectives of the work are aimed at developing
highly efficient power systems for resistance welding, which had high technical and economic indicators and at the same time corresponded to modern standards of electromagnetic compatibility.
The work proposed new approaches, which consist in: issues of identifying the parameters of the welding circuit’s elements, which may change during the welding process
and under the influence of external disturbing factors; determining the components of
power losses and the reasons for the decrease in the energy efficiency of existing power
sources for resistance welding machines; development of power sources for resistance
welding machines with increased efficiency and improvement of their control systems; ensuring the improvement of the energy efficiency of electrical networks supplying resistance
welding machines, including minimizing power losses in the electrical network, maximizing the power factor and optimizing parameters in accordance with the modern standards of
power quality and electromagnetic compatibility.
Keywords: resistance welding machine, power supply, AC-AC chopper, matrix
converter, non-sinusoidal, reactive power, active filter, asymmetry, nonlinear load,
power factor, electromagnetic compatibility
