Arc Welding Power Supply Research Articles

Characterization of an energy efficient pulsed current TIG welding process on AISI 316 and 304 stainless steels

This paper presents the characterization of a TIG welding process carried out by means of an arc welding power supply able to provide dc or pulsed current. The arc welding power supply is based on resonant power converters and an FPGA-based control circuit. Dc and multiple pulsed operations up to 1 kHz with different pulse widths have been tested. The operation of the proposed welding power supply has been compared to that of a high-quality commercial welding machine. Regarding performance, the investigated electrical parameters are: power factor, power conversion efficiency and the energy consumption of the process. The radiography and mechanical properties of the welds have been examined. The mechanical properties of the welded joints characterized through tensile tests are the yield stress, tensile strength and the strain under maximum stress. In addition, the impact properties of the joints were determined through Charpy tests and the curves relating energy absorbed and temperature were obtained. The results show an improved performance of the proposed arc welding power supply over the commercial counterpart, with higher efficiency and power factor, as well as lower energy consumption. The yield stress and tensile strength results indicate that the welded plates using pulsed modes with the proposed power supply are comparable to the reference weld performed with dc operation using the commercial welder. Remarkably, it was observed that the ductility of the welded plates using pulsed modes with the proposed power supply outperforms those of the reference weld carried out with dc arc using the commercial welder.

Large- and Small-Signal Modeling and Control Strategy for Multi-Output Welding Power Supply

Welding technology is a key aspect of the manufacturing industry. With the application of aluminum alloy expanding to more applications, the demand for advanced welding technology for aluminum alloy is constantly increasing. The aluminum alloy welding process requires a multi-output welding power supply to improve aluminum alloy welding quality. In this paper, we design a novel type of multi-output converter that outputs dual DC or single AC according to different welding process requirements and analyze its working principles in detail. Considering the influence of load current variation on the circuit’s performance, we established small-signal models of the DC and AC working modes and large-signal models of the system. Based on these models, we designed a control algorithm for the proposed multi-electrode arc welding power supply. Finally, we constructed an experimental prototype and demonstrated the feasibility of the control strategy. Based on the welding power supply designed in this paper, the welding process control of aluminum alloy can be more accurate, resulting in better welding quality.

Modified Bridgeless PFC-Based Cuk-Sepic Converter With Improved Power Quality for Arc Welding Applications

The novel single-phase Cuk and Sepic power factor correction converter attracted toward arc welding application is highlighted in this paper. The preferred converter is outlined to function in DCM concealed by variations in load voltage and supply voltage to ensure better performance. The control strategy includes a voltage loop, which ensures arc welding process stability and improved input power quality. The designed system is validated with a hardware prototype of 100 W, 48 V, and Matlab/Simulink is used to simulate the arc welding power supply under different working conditions. The reduced input line total harmonic distortion of 1.527% with unity power factor is attained for the rated load in the investigational study. The experimental performance of the propounded converter is bestowed with operating conditions of AC mains (90–270 V) to cohere to the limits delineated by the IEC61000-3-2 standards.

Single-phase front-end bridgeless modified Landsman-Canonical Switching Cell PFC converter for arc welding applications

ABSTRACT This research paper proposes an enhanced power quality in bridgeless modified Landsman-Canonical switching cell (BMLCSC) converter used for arc welding power supplies. This proposed converter topology is presented for circuit component reduction to eliminate the need for a diode bridge rectifier and input filter to make the circuit more compact. The proposed converter is operated on discontinuous conduction mode (DCM). A closed loop PI control circuit with a single voltage sensor is utilized to achieve load regulation, line regulation with high efficiency and quick response. The exploratory performance of preferred framework is simulated using Matlab/Simulink and validated with a hardware prototype of 100 W, 48 V.

GMAW power supply based on parallel full-bridge LLC resonant converter

ABSTRACT In order to reduce energy loss and improve the electrical energy conversion efficiency during the welding process and decrease electromagnetic interference (EMI) of the welding power supply, this paper introduces a gas metal arc welding (GMAW) power supply with an LLC resonant converter. The parallel full-bridge LLC resonant converter was selected according to the characteristics of GMAW, including high open-circuit voltage, low arc voltage, high welding current, and changeable arc load. Load simulation tests and welding tests were carried out using the proposed power supply. Results of load simulation tests show that the switching frequency has a significant effect on the power supply. When the load changes from a light load to the rated load, the shape of the primary-side resonant current gradually approaches the shape of a standard sine wave. Welding test results reveal that the proposed power supply achieves complete arc ignition. The stable working point of the welding process is within the efficient operating range of the LLC resonant converter. The weld bead produced in the welding test was well formed.

Power quality improvements of arc welding power supplies by modified bridgeless SEPIC PFC converter

This paper proposes an efficient bridgeless power factor corrected (PFC) modified single ended primary inductor converter (SEPIC) for arc welding power supplies (AWPS). The overall configuration is composed of two converters: (1) a modified bridgeless SEPIC PFC converter, which is controlled by a PI controller to achieve a high power factor and fast response; and (2) a full bridge buck converter with high-frequency transformer for high-frequency isolation to ensure arc welding stability. The proposed system is simulated under different operating conditions of an AWPS. It is also tested in real time by a hardware-in-the-loop system based on a dSPACE DS1103 control board. The system performances are evaluated based on power quality indices such as power factor, total harmonic distortions of the AC grid current, and voltage regulation. The obtained results show that the proposed controller enhances the weld bead quality by keeping a constant current at the output and a stable arc, meet the international power quality standards and robustness for voltage regulation.

Torch motor control algorithm for low spatter CO2 arc welding of ultra-thin steel sheets

Low spatter CO2 arc welding is often used for ultra-thin steel sheets with a thickness of under 1.0-mm. In this paper, a high speed forward and reverse motion control algorithm for the motor in a welding torch and a dedicated controller for it are presented. The dedicated controller is designed with a motor driver IC (A3930) and a DSP (TMS320F-28069) coded with the proposed motion control algorithm. It is easy to optimize the operating parameters in the proposed algorithm according to various thin steel sheets. Since the torch motor must be able to feed or retract welding wire at a high speed while cooperating with the brushed DC motor in the wire feeder, the performance required in selecting the torch motor is examined and presented in this paper. With the proposed control algorithm, an optimal torch motor and the developed controller, the feeding and retracting motions of the welding wire at high speeds are possible. This results in low heat inputs to the base material and low spatter short-circuiting transfer. To verify the superiority of CO2 arc welding with the proposed torch motor control algorithm and the developed controller, an arc welding robot prototype system was fabricated and 100% purity CO2 gas arc welding with thin steel plates with a thickness of 0.8-mm was performed. This was accomplished with an interlocking a 50 W class brushless DC motor as the torch motor, the developed low spatter motion controller and an arc welding power supply.

Research on Adaptive Controller for Variable Polarity Plasma Arc Welding Power Supply with High-Frequency

Aiming at the problem of output current waveform distortion caused by superimposed high frequency components in the output current of varying polarity of VPPAW power supply. A novel adaptive PID controller with automatic switching is introduced in this paper, and the controller is established based on the evolution path of the operating point of the VPPAW power supply. Compared with the traditional linear PID controller, the adaptive controller proposed in this paper is very suitable for the control of arc load with strong dynamic characteristics and can effectively improve output waveform of the welding system.

Reverse voltage generating circuit for rapid commutation of output current polarity in variable polarity arc welding power supply

The topology of variable polarity (VP) arc welding power supply is composed of a first inverting stage responsible for the adjustment of output current amplitude and a second inverting stage used for the commutation of output current polarity. A reverse voltage generating (RVG) circuit is proposed, which could be applied in the second inverting stage of a VP arc welding power supply to generate a stable reverse voltage with fixed amplitude during the commutation procedure and to make the commutation rate of output current more rapidly. First, a basic circuit unit is designed to illustrate the operating principle of the RVG circuit. Then, the Pspice simulations for the comparison between the RVG circuit and the conventional RC resonant circuit in the half-bridge applications of second inverting stage are carried out to illustrate the superiority of RVG circuit. Finally, an experimental prototype of VP arc welding power supply is established to test and verify the proposed RVG circuit. The experimental waveforms of output current and voltage demonstrate that the RVG circuit is effective and suitable for generating a stable reverse voltage with fixed amplitude, and realizing a rapid commutation of the output current polarity in VP arc welding power supply.

Improved Power Quality Bridgeless Converter-Based SMPS for Arc Welding

This paper proposes a power-factor-corrected bridgeless (BL) switched-mode power supply (SMPS) for welding applications that possesses output voltage control and current limiting feature even during extreme overloading conditions at the output terminals. Eliminating an input diode bridge rectifier minimizes conduction losses and improves thermal utilization of semiconductor devices. The front-end of the proposed SMPS consists of a BL boost converter operating in a continuous conduction mode to attain unity power factor, while at the rear end a pulse width modulation isolated full bridge dc–dc converter is used to regulate the output voltage. The design and implementation of this BL arc welding power supply (AWPS) is presented showing its fast dynamic response to supply voltage and load variations. The performance of the proposed AWPS is examined in terms of power factor, total harmonic distortion of the supply current, efficiency, and output current limit over a wide range of line/load variations. Test results confirm the effectiveness of the proposed AWPS in maintaining an impeccable power quality at utility interface apart from achieving an excellent output voltage regulation and current limiting capability.

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.

Specifics of Pulsed Arc Welding Power Supply Performance Based On A Transistor Switch

Specifics of designing a pulsed arc welding power supply device are presented in the paper. Electronic components for managing large current was analyzed. Strengths and shortcomings of power supply circuits based on thyristor, bipolar transistor and MOSFET are outlined. As a base unit for pulsed arc welding was chosen MOSFET transistor, which is easy to manage. Measures to protect a transistor are given. As for the transistor control device is a microcontroller Arduino which has a low cost and adequate performance of the work. Bead transfer principle is to change the voltage on the arc in the formation of beads on the wire end. Microcontroller controls transistor when the arc voltage reaches the threshold voltage. Thus there is a separation and transfer of beads without splashing. Control strategies tested on a real device and presented. The error in the operation of the device is less than 25 us, it can be used controlling drop transfer at high frequencies (up to 1300 Hz).

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.

Influence of Arc Welding Power Supply on Structural Phase Composition of X12CrNiTi 18-9 (DIN) Weld

The paper presents the results of studies improve efficiency of manual arc welding of austenitic steels. It is in arc welding of austenite steels the use of inverter power supply furthers obtaining more fine-grained structure of added metal and thermal impact zone, shortens thermal impact zone; that improves corrosion resistance of joint weld.

A Power Factor Corrected SMPS with Improved Power Quality for Welding Applications

Abstract This paper presents the analysis, design and implementation of a power factor corrected Arc Welding Power Supply (AWPS) with a boost converter at the front end and three full-bridge (FB) converters connected in parallel at the load end. The modular arrangement of the FB converters offers several meritorious features like usage of power devices with comparatively lower voltage and current ratings, ease of power expandability, easy maintenance, etc. The boost converter operates in continuous conduction mode minimizing the input current ripple and leading to the lowest RMS current thereby improving the input power quality. Individual control loops are designed for each power stage. A dual loop control scheme is employed to incorporate over-current limit on the proposed AWPS which ensures excellent weld bead quality. The proposed AWPS is implemented to validate its performance over a wide range of line/load variations. Test results confirm its fast parametrical response to load and source voltage variations and over-current protection leading to improved welding performance and weld bead quality. The system is found to perform extremely well with very low input current THD and unity power factor, adhering to international power quality norms.

Performance Improvements in an Arc-Welding Power Supply Based on Resonant Inverters

This paper describes improvements developed in an arc-welding power supply based on resonant inverters. A new standby operation sequence based on a sliding phase is proposed in order to reduce the discharge capacitor size. This standby solution also relieves the voltage specification of the resonant inductor. The interleaving operation of paralleled stages and the output connection wires are used to minimize the output capacitor current ripple and also extend the power supply's lifetime. Moreover, synchronous rectification is proposed in order to increase the efficiency and reduce the operation temperature of the output power stage. Finally, sequences are described for establishing and extinguishing arcs. Tungsten inert gas welding is selected for testing operations.

The Development and Research of Welding Power Source Testing Devices Based on ARM Controller

The performance of arc welding power source is an important factor that affecting the use safe and welding quality, so a special equipment for the factory testing is required. The test equipment for arc welding power supply is master-slave structure, and includes hardware and software system. Hardware system complete data acquisition and information display, controlled by embedded micro-controller. The software system complete a graphical user interface programs and collection procedures, developed in the embedded Linux environment. The device enables the automated testing of the welding power source, such as loading, data transmission, reflecting a good man-machine interactivity. The system will be applied to the factory inspection of welding power source, to assess its the quality and performance through tested parameters.

Development of an auto-welding system for CRD nozzle repair welds using a 3D laser vision sensor

A control rod device (CRD) nozzle attaches to the hemispherical surface of a reactor head with J-groove welding. Primary water stress corrosion cracking (PWSCC) causes degradation in these welds, which requires that these defect areas be repaired. To perform this repair welding automatically on a complicated weld groove shape, an auto-welding system was developed incorporating a laser vision sensor that measures the 3-dimensional (3D) shape of the groove and a weld-path creation program that calculates the weld-path parameters. Welding trials with a J-groove workpiece were performed to establish a basis for developing this auto-welding system. Because the reactor head is placed on a lay down support, the outer-most region of the CRD nozzle has restricted access. Due to this tight space, several parameters of the design, such as size, weight and movement of the auto-welding system, had to be carefully considered. The cross section of the J-groove weld is basically an oval shape where the included angle of the J-groove ranges from 0 to 57 degrees. To measure the complex shape, we used double lasers coupled to a single charge coupled device (CCD) camera. We then developed a program to generate the weld-path parameters using the measured 3D shape as a basis. The program has the ability to determine the first and final welding positions and to calculate all weld-path parameters. An optimized image-processing algorithm was applied to resolve noise interference and diffused reflection of the joint surfaces. The auto-welding system is composed of a 4-axis manipulator, gas tungsten arc welding (GTAW) power supply, an optimized designed and manufactured GTAW torch and a 3D laser vision sensor. Through welding trials with 0 and 38-degree included-angle workpieces with both J-groove and U-groove weld, the performance of this auto-welding system was qualified for field application.

LCL-T Resonant Converter With Clamp Diodes: A Novel Constant-Current Power Supply With Inherent Constant-Voltage Limit

The LCL-T resonant converter behaves as a constant-current (CC) source when operated at the resonant frequency. The output voltage of a CC power supply increases linearly with the load resistance. Therefore, a constant-voltage (CV) limit must be incorporated in the converter for its use in practical applications wherein the open-load condition is commonly experienced by a CC power supply, such as in an arc welding power supply. A novel LCL-T resonant converter with clamp diodes is proposed in this paper, which has built-in CC-CV characteristics. Since the CC-CV characteristics are inherent to the converter, and complex feedback control is not required, the proposed converter is rugged and reliable. The principle of operation of the converter is explained. Experimental results on a 500-W prototype are presented to demonstrate the inherent CC-CV behavior of the converter. Simple extensions of the topology featuring variable CV limits are described

A Novel type of High-Frequency Transformer Linked Soft-Switching PWM DC-DC Power Converter for Large Current Applications

This paper presents a new circuit topology of DC busline switch and snubbing capacitor-assisted full-bridge soft-switching PWM inverter type DC-DC power converter with a high frequency link for low voltage large current applications as DC feeding systems, telecommunication power plants, automotive DC bus converters, plasma generator, electro plating plants, fuel cell interfaced power conditioner and arc welding power supplies. The proposed power converter circuit is based upon a voltage source-fed H type full-bridge high frequency PWM inverter with a high frequency transformer link. The conventional type high frequency inverter circuit is modified by adding a single power semiconductor switching device in series with DC rail and snubbing lossless capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge inverter arms and DC busline can achieve ZVS/ZVT turn-off and ZCS turn-on commutation operation. Therefore, the total switching losses at turn-off and turn-on switching transitions of these power semiconductor devices can be reduced even in the high switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules is selected to be 60 kHz. It is proved experimentally by the power loss analysis that the more the switching frequency increases, the more the proposed DC-DC converter can achieve high performance, lighter in weight, lower power losses and miniaturization in size as compared to the conventional hard switching one. The principle of operation, operation modes, practical and inherent effectiveness of this novel DC-DC power converter topology is proved for a low voltage and large current DC-DC power supplies of arc welder applications in industry.