Discussion on large current rectifier bridge

The second generation of high-frequency induction heating power supply is designed to use two KBPC5010, that is, 50A 1000V, two of which reach 100A, and the actual working current is about 20A. Considering that 100A is enough, after the prototype test is completed and there is no problem, batch shipments have found that there are rectifier bridge short circuits in succession, and even some machines have found that there are rectifier bridge short circuits causing tripping during commissioning. This phenomenon is very strange. The first thing to think of is the quality of the rectifier bridge, It was replaced by a rectifier bridge of a domestic listed company, but the defective rate did not decline, and the problem fell into a dilemma.

We searched for this information by ourselves and consulted our predecessors, but the result is not clear. We can't tell why. At this time, we found that the rectifier bridge 26MB80 used in the imported reference model is a small one of IR company, and the current is only 26A, two, that is, only 52A, but there is no problem with others, so we went to find the IR rectifier bridge, Taobao search, even the second-hand IR rectifier bridge, The price is almost the same as that of the domestic products. When I asked about the new products, the price is 4 or 5 times of the existing ones. So why is the difference between the two prices 4 or 5 times? Isn't it just a simple rectifier bridge? I have always thought that the rectifier bridge is something with little technical content.

After finding the price difference, my intuition told me that there was a difference in technology and quality of the rectifier bridge, so I further searched for this information. By chance, I found a key word: glass passivation, glass passivation technology of the rectifier diode, which can improve the impact resistance of the rectifier diode tube. That is to say, the 26MB80 is probably made of glass passivation technology, so this high-power and high-impact diode should be different from the ordinary rectifier bridge. With this concept, after searching for the welding rectifier bridge on Taobao, we found a series of rectifier bridge models with special words for welding machines, such as S50VB100, and searching Baidu also has a similar situation, so we determined the high-power equipment such as welding, The rectifier bridge is dedicated.

Having the above concepts, I contacted the rectifier bridge manufacturer. Unfortunately, the rectifier bridge recommended by Taobao generally needs to be ordered because of the limited quantity, and the cycle is long. The IR rectifier bridge is too expensive and the packaging is not compatible, so I gave up. At this time, I consulted a Taiwan rectifier bridge manufacturer. The information they gave was that KBPC5010 is still a conventional diode, and other rectifier bridges, They all use glass passivation technology, and recommend the model of GBPC5010, which is also useful for welding equipment. We bought some tests, and then we found no abnormalities in small batches. Now we officially use it in batches.