Re: gEDA-user: Non-linear spice models for power sources operating near stall

[Mike Crowe <mcrowe@xxxxxxxxxxxxxxxxxx>]

On Wed, 2010-06-02 at 09:17 -0700, Matthew Wilkins wrote:
> I guess it depends how sophisticated you want your model to be.
>    1.  A simple motor/generator model is a resistor, inductor and voltage
>    source in series.  The voltage source is proportional to speed.  Torque
>    is proportional to current through the winding.   You can measure the
>    values directly from the motor;  keep the rotor stationary for the
>    resistance and inductance measurements.   This is sufficient for a lot
>    of motor modelling work.
>    2.  If you're truly stalling the generator, you might want to map out
>    the inductance measurements at different rotor positions.   Also, you
>    might be able to model cogging torque by putting a sinusoidal current
>    source in parallel with the winding, with phase controlled by a
>    multiple of rotor position.
>    3. More complicated models would vary the inductance depending on
>    rotation speed, electrical frequency and possibly angular position of
>    the rotor...  but hopefully you don't have to go that far.
>    All in all...   I think Spice will be a pretty awkward tool to do any
>    more than (1.).  I'd look at something like University of South
>    Carolina's VTB (Virtual Test Bed).  It's free, but closed source.
Unfortunately, I believe that the model will be more like #3.  The power
source is a periodic hydraulic one.  My ultimate task is to deliver peak
power from the mechanical system regardless of the available input power
(wave action).  In addition to modeling the motor, I will need to model
the mechanical components.    I looked briefly at the SC site, but it
requires a plug-in that I don't have.  
>      __________________________________________________________________
> 
>    From: Mike Crowe <mcrowe@xxxxxxxxxxxxxxxxxx>
>    To: gEDA user mailing list <geda-user@xxxxxxxxxxxxxx>
>    Sent: Wed, June 2, 2010 7:28:43 AM
>    Subject: gEDA-user: Non-linear spice models for power sources operating
>    near stall
>    Hello
>    Somewhat off topic, but....
>    I am working on an energy harvesting device which uses a small
>    generator
>    (<100W).  I am looking for a spice model that I can use as a template
>    to
>    create a model for the motor dynamics near stall.  Can anyone point me
>    to a good starting point?
>    Thanks
>    Mike
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> References
> 
>    1. mailto:geda-user@xxxxxxxxxxxxxx
>    2. http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
> 
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