Improved power-quality-based welding power supply with overcurrent handling capability

This paper proposes a power-factor-corrected canonical switching cell (CSC) converter-based switched-mode power supply for arc-welding applications. In the proposed arc-welding power supply (AWPS), CSC converter operating in discontinuous inductor current mode (DICM) is used to attain inherent power factor correction. The DICM operation substantially reduces the complexity of the control and effectively regulates the dc-link voltage. At the back end, a pulsewidth-modulated (PWM) isolated full bridge dc-dc converter is used to provide a high-frequency isolation, which is mandatory for the arc-welding process. A dual-loop control scheme is utilized to incorporate overcurrent protection and to regulate dc voltage at the output making it suitable for arc-welding applications. Test results are presented to confirm the viability of the proposed AWPS. The performance of the proposed AWPS is evaluated on the basis of total harmonic distortion (THD) of the supply current, power factor, dynamic response, and voltage regulation to prove its effectiveness

A modular converter for welding power supply with improved power quality

This paper presents a single-stage forward AC-DC converter for arc welding power supply. It is desirable to adjust various variables in welding process due to its complex nature. To improve the dynamic response of welding power supply, a three-phase modular power-factor-correction (PFC) converter is used to control a number of parameters, such as welding current, welding voltage, pulse duty cycle, arc striking current, short-circuit current, peak current etc. This topology is designed to operate in discontinuous conduction mode (DCM) to achieve inherent power-factor correction with reduced sensors. The design parameters of the welding power supply are determined to obtain the best achievable power factor with reduced THD (Total Harmonics Distortion) of AC mains current and voltage

Interleaved CSC converter-based power factor corrected switched mode power supply for arc welding

This paper focuses on the design and development of power factor corrected (PFC) interleaved canonical switching cell (I-CSC) converter-based switched mode power supply (SMPS) for arc welding. By interleaving CSC converters, input current is shared amongst them so that high reliability and efficiency is obtained for high-power applications. I-CSC converter is designed to operate in discontinuous conduction mode (DCM) to achieve unity power factor inherently at utility interface. DCM operation together with interleaving technique bring additional size and performance benefits such as reduced reverse recovery loss, less switching stress, high efficiency, etc. I-CSC converter is followed by three full bridge buck converters in parallel to perform DC-DC conversion and to provide galvanic isolation desired for safe operation during welding. The modularity of SMPS allows flexibility in current, voltage and power levels, usage of devices of lower rating and ease of maintenance. The proposed SMPS operates in constant voltage mode; however, during extreme overload condition it maintains constant current at the output to improve the weld bead quality. Test results confirm the effectiveness of proposed SMPS in maintaining power quality indices within the acceptable limits of international standards over wide load range while over-current handling capability leads to improved welding performance

Power quality improved SMPS using bridgeless isolated zeta converter for welding applications

A single-phase power factor corrected bridgeless isolated zeta converter is presented in this paper for arc welding power supplies. Eliminating diode bridge rectifier at the front end minimizes the conduction losses and enhances the thermal utilization of the converter switches. The converter is functioning in discontinuous conduction mode pertaining to the magnetizing inductance of the transformer to enable power factor correction inherently. A double loop controller is proposed to integrate over-current limiting capability along with regulating the DC arc welding voltage. The proposed switched mode power supply (SMPS) is designed to operate under a wide range of load and supply voltage conditions with improved input power quality (IPQ). The performance of the SMPS is simulated and the test results are evaluated on the basis of input power factor as well as total harmonic distortion of the supply current, voltage regulation and robustness to validate the viability of the proposed SMPS. A prototype of the proposed SMPS is developed and the experimental results have been obtained which establish the efficacy of the proposed bridgeless SMPS in maintaining excellent IPQ at the utility interface point

PFC bridgeless converter for welding power supply with improved power quality

This paper proposes a power factor corrected (PFC) two stage AC-DC converter suitable for arc welding applications. The proposed circuit is made up of a bridgeless (BL) zeta converter at the front end and full bridge (FB) buck converter for high-frequency isolation. The BL zeta converter eliminates the input diode bridge rectifier (DBR) thereby minimizing the conduction losses. The discontinuous current mode (DCM) operation of BL zeta converter naturally provides power factor correction at AC mains in an effective manner. The proposed converter offers several meritorious features like fast parametrical response to load and source voltage variations andinherent short-circuit current limit resulting in better welding performance and weld bead quality. The performance of the system is investigated to assess its power quality in terms of input power factor (PF), total harmonic distortion (THD) of the AC mains current, voltage regulation and robustness. The system is found to perform extremely well adhering to international power quality norms

Power quality improvement using three phase modular converter for welding power supply

This paper deals with the power quality improvement in an arc welding apparatus. An efficient arc welding process needs fine and fast dynamic control of energy flow for good weld quality and productivity. The existing welding machines have the problem of low power factor and high harmonic content at the utility interface. A three-phase modular power-factor-correction converter connected to a pulse width modulated DC-DC converter is proposed for welding power supply. The full-bridge modular converter provides attractive features such as inherent power factor correction, simple DC-DC switching control, high frequency transformer isolation and single-stage power conversion. The converters are designed to operate in both CCM and DCM operation in different power ratings. The proposed system significantly improves the dynamic response of the converter. The criteria for obtaining high power factor is being analyzed and the circuit parameters are determined to obtain the best achievable power factor with reduced THD (Total Harmonics Distortion) of AC mains current and voltage

Power factor corrected welding power supply using modified zeta converter

A power factor (PF) corrected single stage, two-switch isolated zeta converter is proposed for arc welding. This modified zeta converter is having two switches and two clamping diodes on the primary side of a high-frequency transformer. This, in turn, results in reduced switch stress. The proposed converter is designed to operate in a discontinuous inductor current mode (DICM) to achieve inherent PF correction at the utility. The DICM operation substantially reduces the complexity of the control and effectively regulates the output dc voltage. The proposed converter offers several features, such as inherent overload current limit and fast parametrical response, to the load and source voltage conditions. This, in turn, results in an improved performance in terms of power quality indices and an enhanced weld bead quality. The proposed modified zeta converter is designed and its performance is simulated in the MATLAB/Simulink environment. Simulated results are also verified experimentally on a developed prototype of the converter. The performance of the system is investigated in terms of its input PF, displacement PF, total harmonic distortion of ac mains current, voltage regulation, and robustness to prove its efficacy in overall performance

Welding power supply with improved power quality using Sheppard-Taylor converter

This paper presents a single-phase Power Factor Corrector (PFC) based on the Sheppard-Taylor topology suitable for welding applications. In order to ensure unity power factor at the input AC mains, a Pulse-Width-Modulated (PWM) control is developed. The input inductance of the proposed converter works in discontinuous current mode (DCM). Major favorable features of this converter like inherent short-circuit current limitation and fast parametrical response to load and source voltage conditions will result in better welding performance and weld quality. The performance of the entire system is evaluated on the basis of Total Harmonic Distortion (THD) of the source current, input power factor, dynamic response, voltage regulation and robustness to prove its effectiveness in terms of excellent power quality

A PFC based bridgeless converter with improved power quality for welding applications

A Power Factor Corrected (PFC) two stage, Bridgeless (BL) Cuk converter based switched mode power supply is proposed in this work for arc welding applications. The absence of input Diode Bridge Rectifier (DBR) reduces the conduction losses and improves the thermal utilization of the converter's switches. The front-end comprises of a BL-Cuk converter operating in Discontinuous Conduction Mode (DCM) to attain unity Power Factor (PF) at the AC mains while at the back end, a PWM isolated Full Bridge (FB) DC-DC converter is used to regulate the output DC voltage. The performance of the system is examined in terms of the input PF, Total Harmonic Distortion (THD) of the ac mains current, voltage regulation and robustness. The obtained dynamic characteristics of this proposed topology depicts a constant voltage mode in various ranges of welding currents and inherent parametrical short circuit protection. Simulation results are presented to confirm the effectiveness of the proposed Arc Welding Power Supply (AWPS) in terms of excellent Power Quality (PQ)

Three-phase push-pull modular converter based welding power supply with improved power quality

This paper deals with an efficient method of improving power quality for arc welding power supply. The analysis and design of modular three-phase ac-dc converter using three single-phase high frequency transformer based push-pull converter are carried out for welding power supply. A three-phase modular power-factor-correction (PFC) converter connected to a pulse width modulated (PWM) dc-dc converter ensures nearly unity power-factor of arc welding power supply and also suppresses input current harmonics. It includes the operation of a modular converter in discontinuous-conduction-mode (DCM) of operation with inherent power factor correction (DCM-PFC). This PFC converter exhibits ease of control, high frequency isolation as well as single stage power conversion. The fast dynamic response of this converter has a constant voltage mode in the range of welding currents and inherent parametrical short-circuit limit. This leads to improved arc stability and weld bead quality