This study proposes a suitable DC-DC converter topology with improved power quality at the input side for micro-butt welding machine by evaluating different power factor correction (PFC) techniques and DC-DC converter topologies. Firstly, different control strategies of boost converters such as peak current controlled PFC, average current controlled PFC and hysteresis current controlled PFC are discussed for minimising input current distortions and improving the power quality. Also, the current loop gain stability analyses are presented using small-signal model for selecting the best model and optimisation of the same. Secondly, the important key parameters such as cost, size, weight, complexity in implementation and other application dependent parameters of various isolated type of DC-DC converter topologies are compared and the best DC-DC converter topology is selected for the proposed application. Finally, the modelling and stability analysis is performed on the DC-DC converter and optimisation is achieved for the welding current controller. The software packages MATLAB/Plecs/OrCAD PSpice are used for simulation and implementation of the desired circuitry with optimised design. A prototype has been developed based on optimised design, hysteresis current controller for PFC and DC-DC converter; and the control algorithm is implemented DSP TMS320F2812 and the experimental results were discussed. 2 DC-DC converter topologies for micro-butt welding The DC-DC converter consists of inverter, high frequency transformer (HFT), rectifier and filter. The primary requirements of welding power supply are galvanic isolation from main supply, DC current (150-600 A) regulation with max of 5 V and capability to withstand during the short-circuit condition. The general criteria for selection of DC-DC converter are cost, weight, size and ease of

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The most of the industrial welding applications involving of electronic circuits such as AC-DC, and DC-AC and AC-DC converters. The input power factor of such a system is reduced due to the presence of more harmonics due to the non-linear devices within the converters which leads to creates more adverse effects. There by a need of suitable AC-DC converter with power factor correction technique to condition the supply current. The power factor correction rectifier that requires best current control from i) Peak current control ii) Average current control and iii) Hysteresis current control. This paper presents a comparative analysis from above mentioned power factor correction control topologies. The simulation of these control techniques are carried out using “Plecs” with “MATLAB/SIMULINK”. The simulation results shows that Hysteresis control has low THD, good DC link voltage regulation and better performance than other control techniques. The same control technique is implemented in TMS320F2812 DSP and results are proved.