Last week I was out shopping at one of my electronic resources and came across some big Mitsubishi CM200DY-12H 600 Volts 200 Amp IGBTs. I bought two pairs of them for my future projects. Below is a picture of a pair of them on the nicely machined heatsink. The overall length of the heatsink is about 8 inches long, for size reference.
I’ve worked on a few projects which have needed large amounts of power control and I’ve always had to resort to big transformers and many large power resistors in order to be able to run the devices. Copper is heavy and big resistors are hard to find surplus in the right values, and new ones are too expensive for my projects.
I’ve never worked with IGBTs before, so I’ve been doing a lot of reading on their applications. There are quite a few documents out there on how to use them and the special drive considerations involved as it relates to inverters and PWM average power control.
Recently I finished building a Copper Vapor Laser (CVL) but I had to use a mechanical interrupter to provide the required pulse timing and spacing. While I was looking up IGBT information I found a great document on building an IGBT drive circuit for copper vapor lasers, which includes a magnetic pulse compressor and some engineering information. The power requirements for the laser in the document are quite high, needing a 550 Volt 20 Amp switch mode power supply. I’d love to see the diagrams for the power supply, but they are unfortunately behind a paywall and out of reach.
Also while doing online research I found that book “Advanced High Voltage Power Device Concepts” which looked like it would be really informative and contains a lot of information about all sorts of devices from thyristors (SCRs) through IGBTs, this is the kind of information I like to read. I don’t have $175 for the book, but it looks really interesting. I don’t read regular fiction/non-fiction books much, maybe 200 pages in the last 10 years, but I find technical books and documentation really interesting.
Amazon allows you to read pieces of books here and there, so with a little bit of poking you can get some of the content of the book. It looks really informative to me, but I’m sure there are other books out there with great information as well.
Another thing that I think would be a fun and educational project is to build a TIG Welder. I did some digging around online and found a site by Dave Barrett and Will Coatzee for a TTL/CMOS based IGBT 180 Amp TIG welder that uses an AC stick welder as a power supply. The design looks quite well thought out and has schematics, photos and drawings for a complete setup. I think this would provide a great starting point for a modernized, micro-controller based design. Unfortunately this project was linked through Hack-A-Day at some point and the author received much more attention than he ever wanted, as well as demands for parts list, Gerber files, etc from enthusiastic readers. He is no longer providing any kind of support for the project as he was swamped with what he called spam and junk mail. It might be worth downloading the page in case he decides to remove it. The parts list is in the schematic and the PCB layout is also in the schematic you just have to massage them out yourself. 😉
Another laser use for these would to be the construction of a power supply for my large Argon laser tube. I’ve been wanting to fire that tube up for a while now but just haven’t managed to pull the components together. Due to their large power demands, about 25-30 amps at 200 volts, they require large power supplies with, at minimum: big transformers, big capacitors and big resistors. To be built properly, they need current regulation.
Many years ago I did build a DIY pass bank current regulated power supply for my 40mw multi-line argon, which can be seen on my laser site, and that turned out pretty well. It’s based off of schematics from Sam’s Laser FAQ here’s a link to the Argon Laser Power Supply section.
In the Laser FAQ linked above, there is a section titled “Mario’s Current Regulated Ion Laser Power Supply (MC-IL1)” which is worth a look. It eliminates the pass back and replaces it with an IGBT on a current feedback loop to control the power to the small air cooled ion laser tube. This design could likely be modified for larger tubes and current requirements as well as additional current control via light sensor, interlocks, over-current protection, etc. It’s something I’m seriously considering for my old water cooled Meditech tube. The best solution would be to buy an existing power supply, however the prices for supplies for these old ion lasers seem to be going UP for some reason instead of down, making them difficult to obtain.
At any rate, I thought IGBTs would be out of my reach for quite a while due to the costs of the larger devices, since I have been able to gain access to some, I’m now looking forward to some projects I may be able to do with them if I can manage to gather the other components I need.
If you know of any links or other good resource for IGBT or IGBT projects, please let me know in the comments below, it’d be greatly appreciated. -Jon