Welding inverter is an alternative to a conventional welding transformer. Modern semiconductors allow to replace the traditional mains transformer with a
switching power supply, which is much lighter, smaller and allows easy current adjustment via a potentiometer. The advantege is
also that the output current is DC. DC current is less dangerous than AC and prevents arc extinction.
For this inverter i chose topology, which is the most common in welding inverters - forward converter with two switches.
In my article about switchning supplies it is a topology II.D.
Input mains voltage passes through an EMI filter and is smoothed with high capacity capacitors. Since the inrush current of those capacitors would be too high,
there's a softstart circuit. After switching ON, the primary smoothing capacitors are charging via resistors, which are later bypassed
by the contact of a relay. As power switches, IGBT transistors IRG4PC40W are used.
They are driven through a forward gate-drive transformer TR2 and shaping circuits with BC327 PNP transistors.
The control integrated circuit is UC3844. It's similar to UC3842, but it has its pulse-width limited to 50%. Working frequency is 42kHz.
Control circuit is powered by an auxiliary power supply of 17V.
Current feedback, due to high currents, is using a current transformer Tr3. Voltage drop accros the sensing resistor 4R7/2W is approximately proportional to the output current.
Output current can be controlled by potentiometer P1, which determines the threshold of the current feedback. Threshold voltage of the pin 3 of UC3844 (current sensing) is 1V.
Power semiconductors require cooling. Most of the heat is dissipated in output diodes. Upper diode, consisting of 2x DSEI60-06A, must in worst
case handle the average current of 50A and the dissipation of 80W (total of both diodes).
Lower diode STTH200L06TV1 (doube diode package with both internal diodes connected in parallel) must in worst
case handle an average current of 100A and the dissipation of nearly 120W. Maximum total dissipation of the secondary rectifier is 140W. The heatsink must be able to handle it.
To the thermal resistance you must include the junction-case Rth, case-sink Rth and sink-ambient Rth.
DSEI60-06A diodes don't have insulation pads and the cathode is connected to the the heatsink. Output choke L1 is therefore in the negative rail. It
is advantageous because in this configuration, there's no high-frequency voltage on the heatsink.
You can use another type of diodes, for example a parallel combination of a sufficient number of the most accessible diodes,
such as MUR1560 or FES16JT. Note that the maximum average current of the lower diode is twice the current of the upper diode.
Calculation of the power dissipation of the
IGBTs is more complicated because in addition to conductive losses there are also switching losses. Loss of each transistor is up to about 50W.
It is also necessary to cool the reset diodes UG5JT and the mains bridge rectifier. The power dissipation of the reset diodes depends on the construction of Tr1
(inductance, stray inductance), but is much lower than the dissipation of the IGBTs. The rectifier bridge has a power dissipation of up to about 30W.
UG5JT diodes and the rectifying bridge are placed on the same heatsink as the IGBTs. UG5JT diodes
also can be replaced with MUR1560 or FES16JT or other ultrafast diodes.
During construction it is also necessary to decide the maximum loading factor of the welding inverter, and accordingly select size of heatsinks, winding gauges and so on.
It is also good to add a fan.
Switching transformer Tr1 is wound on two ferrite EE cores, each with a central column cross section 16x20mm. The total cross section is therefore
16x40mm, the core must have no air gap. 20 turns primary winding is wound using 14 wires of a 0.5 mm diamater. It would be better to use 20 wires, but they
didn't fit into my core.
Secondary winding has 6 turns of a copper strip (36 x 0.5 mm). Forward gate-drive transformer Tr2 is made with an emphasis on low stray inductance. It is trifillary wound,
using three twisted insulated wires of 0.3 mm diameter, and all the windings have 14 turns. Core is made of material H22, middle column has a diameter of 16mm, with no gaps.
Current sensing transformer Tr3 is made from an EMI suppression choke on a toroidal core. The original winding with 75 turns of 0.4 mm wire works as a secondary.
Primary has just 1 turn. Polarity of all the transformer windings must be kept (see dots in schematic)!
L1 inductor has a ferrite EE core, middle column has cross section 16x20mm. It has 11 turns of a copper strip (36 x 0.5mm) and the total air gap in the magnetic circuit is 10mm.
Its inductance is cca 12uH.
The auxiliary 17V switching power supply, including Tr4, is described in more detail
here.
The simplest welding inverter on Pic 1 has no voltage feedback. Voltage feedback does not affect the welding, but affects the power consumption and heat losses in the idle state.
Without the output voltage feedback there is quite high output voltage (approximately 100V)
and the PWM controller ia running at its max duty cycle, thereby increasing the power consumption and heating of components.
Therefore, it is better to implement the voltage feedback. You can inspire on Pic 2. The feedback can be connected directly because the controll circuit is
isolated from mains. The reference voltage is 2.5V. Select the R2 to set the open circuit voltage.
You can find useful info in datasheet of UC3842, 3843, 3844, 3845 or in its another datasheet.
Inspiration for modifications you can also find in 3-60V 40A supply.
Interesting links from which I drew:
http://svarbazar.cz/phprs/index.php?akce=souvis&tagid=3
http://leo.wsinf.edu.pl/~leszek/spawarki/
http://www.y-u-r.narod.ru/Svark/svark.htm
http://www.emil.matei.ro/weldinv3.php
http://nexor.electrik.org/svarka/barmaley/kosoy/shema.gif
and a little modified: http://nexor.electrik.org/svarka/barmaley/kosoy1/shema.gif
Interestingly, while the show was a Japanese creation, it was a co-production with the Canadian company Nelvana. In a twist of fate, the series initially struggled to gain traction in Japan but exploded in popularity in North America. This led to the creation of multiple sequel seasons— New Vestroia , Gundalian Invaders , and the never-broadcast-in-Japan Mechtanium Surge —all of which aired in Canada and the U.S. well before they ever reached Japanese audiences. This unusual release history means that many fans grew up with the English version as their default. However, a growing movement has been encouraging fans to go back and experience the original Japanese language track, which is often cited as the superior version.
The story takes place in the fictional city of Tokyo, where a group of kids, known as Brawlers, engage in a game called Bakugan. The objective of the game is to defeat your opponents by using powerful creatures known as Bakugan, which are summoned from a special ball-like device called a Bakugan.
Why the Japanese Dub is a "Hot" Topic in the Anime Community
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Suzuki portrays Shun with a quiet, stoic, and deeply emotional tone, emphasizing his tragic backstory and ninja heritage without making him feel detached. bakugan battle brawlers japanese dub english subs hot
: Fans often prefer the Japanese voice acting for its consistency. For example, the Japanese version of Drago maintains a more consistent warrior personality, whereas some viewers find his English counterpart occasionally "bipolar" regarding his love for battle. Key Differences at a Glance Japanese (Sub) English (Dub) Protagonist Name Danma "Dan" Kuso Daniel "Dan" Kuso BGM Original Score (Takayuki Negishi) New Western Score Censorship None (includes references to death) Heavy (death/violence removed) Aspect Ratio 16:9 Widescreen Often 4:3 Fullscreen Where to Find the Japanese Dub with English Subs
The Ultimate Guide to Watching Bakugan Battle Brawlers in Japanese Dub with English Subs
Watching Bakugan Battle Brawlers in its original Japanese dub with English subtitles offers a significantly different experience compared to the westernized English dub, particularly regarding maturity, character depth, and consistent internal logic. While the English dub is celebrated for its nostalgic voice acting and iconic soundtrack, many viewers consider the Japanese sub to be the "superior" way to experience the story's original intent.
The most striking difference between the English dub and the Japanese subtitled version of Bakugan lies in the overall tone. The English localization, produced by Nelvana, was explicitly tailored for a younger Western audience. Dialogue was rewritten to include campy humor, stakes were often downplayed, and censorship was applied to fit strict broadcast standards. Interestingly, while the show was a Japanese creation,
Bakugan Battle Brawlers: Why the Japanese Dub with English Subs is a "Hot" Choice
The Japanese voice cast delivers a highly charged, authentic anime experience that reshapes how viewers perceive the main cast. The emotional gravity of the voice acting elevates the series from a toy-commercial show to a legitimate shonen battle anime. Notable Voice Cast Differences:
Fans often seek the original Japanese "sub" because the English dub (produced by Nelvana) made significant changes to tone and content:
: Several violent or intense scenes were removed, such as Hydranoid impaling Reaper with his tail . well before they ever reached Japanese audiences
The Japanese version features the original music score, which is widely considered more atmospheric and fitting for the dramatic, high-stakes battle scenes.
Often, specialized anime platforms may host the original, uncut Japanese version.
Propose your preference, and I can narrow down the for you. Share public link
