Re: Pushing the IGBT Envelop

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz" <acmdq-at-uol-dot-com.br> 

Tesla list wrote:

 > Original poster: "Greg Leyh" <lod-at-pacbell-dot-net>

 > Nice program!  I'll have to work with it some more to understand it more
 > fully, though.
 > For some reason it took my inputted values and changed them?  I probably
 > entered them
 > in the wrong spot.

The program really has some unclear parts... When you choose one of the
two desigh buttons, what you have entered after pressing the "edit
elements" button is replaced.
The "lossy design" is the impedance matching idea using
a Butterworth filter. It optimizes the input impedance for a certain
amount of load. The "lossless design" is similar to the design of a
magnifier, with the operation mode defined by three integers k:l:m,
that are the ratio of the three frequencies that appear in the
waveforms. Note that both designs are almost identical if the load
is removed. The other parameters are for the built-in simulator, that
always works over the element values that appear when the "edit
elements"
button is pressed. The simulator assumes a linear resistive load, that
is on of off all the time, and leaves the driver operating all the
time (to be improved later).

 > Have you studied primary drive scenarios that attempt to recover the unused
 > energy from
 > the secondary?  I think this feature will be essential for the ALF.  I'm
 > presently designing
 > an energy recovery scheme into the 1:12 scale ALF prototype, and hope to
 > test it soon.

The lossless design ideally recovers all the energy, at least if some
of it is removed from the output capacitance at the instant when the
maximum voltage is reached. It would also recover most of the energy
left unused by a load connected to the output when the output voltage
is close to the maximum. But the driver would have to operate with
reverse
current for this, and be active for the full output "beat".

What is ALF?

Antonio Carlos M. de Queiroz