-The study is devoted to the important issue of enhancing the circuitry and characteristics of power supplies for micro resistance welding machines. The aim of the research is to provide high quality input current and to increase the energy efficiency of the output pulse generator by means of improving the circuit topologies of the power supply main blocks. In study, the principle of constructing the power supply for micro resistance welding, which provides high values of output welding current and high accuracy of welding pulse formation, makes it possible to reduce energy losses, and provides high quality of consumed input current, is represented. The multiphase topology of the charger with power factor correction based on SEPIC converters is suggested as the most efficient for charging the supercapacitor storage module. The multicell topology of the supercapacitor energy storage with voltage equalizing is presented. The parameters of the converter cells are evaluated. The calculations of energy efficiency of the power supply's input and output converters based on suggested topologies are carried out and verified in MATLAB Simulink. The power factor value greater than 99 % is derived.

The paper represents resistance welding characteristics and construction features of power supplies for resistance welding. The authors give an overview of circuit topologies of converters for resistance welding and distinguish the most promising one — the transistor buck converter with a synchronous transistor. It is shown that in order to ensure acceptable energy efficiency of power supply for resistance welding machines, while maintaining sufficient accuracy of current regulation in a welding contact, special modes of pulse transistor converters are used. The analysis of resistance welding features — high currents, low voltages — makes it possible to presume that the evaluation of the power losses in semiconductor elements only is insufficient and needs to be complemented by taking into account the losses on the inductive element of the converter circuit. In this work, the authors propose the method of estimating the power losses in the pulse buck converter of the power supply of resistance welding machine, which allows for more accurate calculations at the design stage due to consideration of the power losses on the inductive element of the circuit. The methodology is to calculate the total power losses as the sum of power losses on all individual elements of the circuit. Power losses on inductance is calculated using the Steinmetz equation. The calculations carried out with this technique proved the advisability of taking into account the power losses on the inductive element, especially in the region of high frequencies. The obtained diagrams demonstrated the dependency of the power losses in the converter on the frequency at different values of current and voltage.

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Національний технічний університет України «Київський політехнічний інститут імені Ігоря Сікорського» kpi.ua Київ, Україна Реферат-З метою підвищення ефективності використання гібридного ємнісного накопичувача енергії джерела живлення для контактного мікрозварювання запропоновано схемну топологію системи контролю розподілу енергії між ємнісними елементами накопичувача, що забезпечує стабільність вихідної напруги при значних пікових навантаженнях в умовах обмеженого доступу до промислової мережі. Здійснено імітаційне моделювання роботи запропонованої системи, отримано діаграми напруги та струму, що ілюструють процес заряду суперконденсаторного модуля від акумуляторної батареї та принцип дії комірок балансування. Бібл. 10, рис. 3, табл. 1. Ключові словаавтономне джерело живлення; гібридний ємнісний накопичувач; акумуляторна батарея; суперконденсатор; балансування напруги; контактне мікрозварювання.