Re: [TCML] Mosfet H bridge questions

[Henry Hallam <henry@xxxxxxxxxxxxxxxx>]

I don't think the autotransformer idea is likely to work very well.
You can use an isolated gate drive transformer if the switching
frequency is going to be high enough, or something like the IR2214
(http://www.irf.com/product-info/datasheets/data/ir2114ss.pdf) which
is a chip designed for exactly this purpose.

Good luck

Henry

On Sun, May 30, 2010 at 9:17 AM, Scott Bogard <sdbogard@xxxxxxxxx> wrote:
> Hi All,
>     I'm trying to wrap my head around just exactly how one would use an N
> channel MOSFET/IGBT on the high side of an H bridge.  What I am trying to
> accomplish is to build a more or less "universal" bridge that with
> substituting components per necessary ratings could be used for everything
> from a flyback driver, to a leg of a PWM for a VFD (apparently VFDs are
> actually feeding a PWM signal that varies duty cycle with time to simulate a
> sine wave, they don't actually put out a sine wave at all...) even
> eventually a crude DRSSTC, using the same PCB.  I plan on using an arduino
> or other similar programmable controller with multiple outputs to generate
> signals for these various applications.  Here is what I came up with, I want
> to know if it is at all viable, and keeping parts to a minimum is a key
> point for me being a mechanical guy.
> http://bogard.110mb.com/generic%20H%20bridge.bmp
> If it doesn't load take out the %20's and replace them with spaces.  The low
> side signals can be driven off a tap of the autotransformer, which I don't
> really know how to approach designing or if it will even work in this
> application (or even if it is really necessary...)  Obviously the number of
> turns will be dependent on input voltage (more like 12 or 24V for flybacks,
> 400V for PWM applications.)  I will pick the wire gauge based on the current
> capacity of the transistor, but as how to know I have an inductance that
> will keep current low enough that my transistor will be able to survive, I
> don't know how to approach this, or how to size my transistor for voltage
> considerations (would it see 120V or only the saturation voltage?)  This
> stuff is not my field so be gentle so very wise collection or electrical
> engineers.
>
> Scott Bogard.
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>



-- 
Henry Hallam

Sent from my Laptop
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla