Bondarenko I. Multicell-type Transistor Converter with Combined Continuous and Pulse Control for Micro Resistance Welding

The object of research: formation of current pulses for micro resistance welding. The purpose of research: improving transistor converters of micro resistance welding machines towards precise forming welding current and increasing energy efficiency. Methods of research: theory of electrical and electronic circuits, methods of control theory, methods of analysis of linear and nonlinear circuits, methods of mathematical modeling, simulation and physical modeling, methods of structural and parametric optimization, methods of statistical treatment. Mathematical calculations and simulations were carried out using the software MATLAB (Simulink), MathCAD and MS Excel. Theoretical and practical results and innovations: the principle of construction of multicell-type transistor converter for generating current in micro resistance welding machines is first proposed, each cell of it includes a linear converter and a switching regulator, that allows to obtain necessary current value and to combine the advantages of continuous and pulse controls; the new principle of transistor converter's cells control is proposed, according to that, the cells are connected to load gradually, following the reference signal level, each newly connected cell starts operating in continuous mode and then, after reaching a predetermined maximum current level, it operates in switch mode, any time only one cell generates current in continuous mode and others stabilize current in switch mode, that control principle provides accurate forming welding current and increasing energy efficiency; the dynamic properties of the transistor converter with combined continuous and pulse control are first defined, as well as the relationships of converter energy efficiency from cells number and current schedule power index; circuits of proposed multicell-type transistor converter with combined continuous and pulse control were designed; recommendations for the converter structure optimization and its use were given. A subject degree of introduction: were practically applied in SSPE "Photon" (Alchevsk) in development of power and control parts of multicell-type converter VIP1,5-15; used in educational process at Electronic Systems Department of Donbas State Technical University. Sphere of use: power supplies for micro resistance welding machines of responsible appointment.