Friday, February 27, 2009

Challenges firing an IGBT

So it turns out firing an IGBT is a little more complicated than I thought. It turns out the gate acts like a capacitor, so if you charge it with a positive voltage to turn on the transistor, it stays on unless you put a negative charge on it to turn it off.

I've found an integrated circuit from fairchild semiconductor, the FOD3180, which does this as well as using an opto isolator. I've ordered a few from Arrow electronics as I couldn't find a local supplier.

more to follow

Friday, February 6, 2009

Side show

If anyone is interested, I am also building a new bed. It's kind of wacky.

Updated Photo

So here is the test VFD is it sits today. Sanguino is working generating a PWM 3 phase sin output to the firing cards. I have a 12v supply which is powering everything at the moment. I need to pick up some wire to hook the firing cards to the IGBTs, kluge some power to apply to the IGBTs, and then some big resistors or light bulbs or something to pump power through. I've found some help in locating a suitable vehicle and motors. Updates soon.
Posted by Picasa

Monday, February 2, 2009

Setup of controller

Here is a photo of the mounted Sanguino, IGBT's, one of two PWM cards, a breadboard and a 12 volt power supply.
I screwed up one of the PWM cards by installing transistors the wrong way, and then desoldering badly and messing up a trace. Arg.
Posted by Picasa