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Power Factor Corrected Welding Power
Supply Using Modified Zeta Converter
Abstract:
A power factor 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 primary side of high frequency transformer (HFT). This,
in turn, results in reduced switch stress. The proposed converter is designed to
operate in discontinuous inductor current mode (DICM) to achieve inherent power
factor 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 like 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 enhanced
weld bead quality. The proposed modified zeta converter is designed and its
performance is simulated in 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 power factor (PF),
displacement power factor (DPF), total harmonic distortion (THD) of AC mains
current, voltage regulation and robustness to prove its efficacy in overall
performance.
Existing system:
 Welding is one of the most important manufacturing processes. Amongst
various welding techniques, arc welding is the most commonly used
fabrication process in every industry - large or small.
 At present, arc welding has become an integral part of several industries like
automotive, aerospace, construction, medical, energy, chemical etc. A
significant amount of total generated electrical energy is consumed by arc
welding power supplies (AWPSs) and it is expected to increase
tremendously in the wake of more and more industries coming up.
 Various topologies have been reported in order to meet the essential
requirements of international power quality (PQ) standards like IEC 610003-2. These have led to the development of several switched mode power
supplies (SMPSs) with high DC current and low DC voltage output for
welding.
 Although these SMPSs are highly efficient, however, due to their non-linear
behaviour they draw highly distorted current resulting in low power factor
(PF) and high total harmonic distortion (THD).
 This deterioration in PQ leads to increased system losses, degrading the
reliability of electrical equipments, high electromagnetic interference, etc.
Consequently, it is essential to use a power factor correction (PFC) based
AWPS with improved PQ.
Proposed system:
 In order to minimize the switch stress and complexity of the control circuitry
by way of eliminating the input current sensor, this paper deals with the
analysis, design and development of two switch modified zeta converter
operating in DICM, with high-frequency isolation, regulated output voltage
and improved power quality.
 For achieving wider operating range, DICM operation is convenient which
also offers additional advantages like reduction in the number of sensors and
component size. This, in turn, reduces the complexity of the control circuit
and makes the power supply compact.
 Moreover, an effort has been made to incorporate over-current withstand
capability in the proposed converter to make it suitable for arc welding.
This, in turn, enhances the quality of weld bead.
 Therefore, this PFC converter based AWPS is used to control various
variables, such as welding current, welding voltage, pulse duty cycle, overload current, etc. The developed prototype of proposed modified isolated
zeta converter is capable of providing 40A of welding current with a
significant improvement in the input power quality.
Circuit diagram:
Advantages:
 Reduction in the number off sensors
 Component size is reduced
Applications:
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Automotive
Aerospace
Construction
Medical
Energy
Chemical etc.
Reference:
[1] Limits for Harmonic Current Emissions, International Electro technical
Commission Standard, 61000-3-2, 2004.
[2] M.K. Kazimierczuk, “Pulse-width Modulated DC-DC Power
Converter”, John Willey & Sons, USA, 2008.
[3] B. Singh, S. Singh, A.Chandra, K. Al-Haddad, “Comprehensive study of
single-phase ac-dc power factor corrected converters with highfrequency
isolation”, IEEE Trans. Ind. Informatics, vol. 7, no. 4, pp.
540-556, Nov. 2011.
[4] Jian-Min Wang, Sen-Tung Wu,“A novel inverter for arc welding
machines”, IEEE Trans. Ind. Electronics, vol. 62, no. 3, pp. 1431 - 1439,
Mar. 2015.