Re: Successful induction motor test

[Seth <sethea@attbi.com>]

Arthur-

Congratulations on getting your AC drive running! I  might suggest
buying a large diameter iron pulley and couple it to the shaft of your
motor so you can start getting a feel for controlling regen with
additional inertia. Be prepared to see the voltage rise even higher. 

Seth

Arthur Matteson wrote:
> 
> Dear fellow AC'ers and EV'ers,
> 
> Today I tested my (TI's) space-vector code with my system, with 120VAC one-phase in and 115VAC three-phase out, on a 3/4HP motor.
> It is very impressive.  To my surprise, regenerative braking worked without me even trying - I forgot about it when I first turned
> down the speed.  You can really slow down the shaft quickly.  I measured the voltage on the bus capacitor (3300uF) jumping up from
> 165V to 225V when I turned the speed down even at a medium rate.  1800 RPM is fast, but 3600 is really whizzing along.  So far this
> project has been a piece of cake.  I haven't had any problems with anything.  The IGBTs don't even get warm.  The TMS320F241 works
> very well, but it has a few bad resets once in a while.  Any suggestions to replace the 1K pullup (or pulldown, I forget)?
> 
> I've just completed my subwoofer amplifier - 500-600W maximum power, class-D, from 12V.  I realized that I was using a powder core
> before, and getting bad results; the new ferrite works beautifully.  I didn't even bother to make a digital regulation circuit - I
> just used the UC3525's op-amp (PWM).  I'll expand this power supply onto my 4" core(s), when the rest arrive.  I can't do much with
> only one side of a U-core.  They should have sent me 12...whatever happened to our deal...got to call them again...   In the mean
> time I'll work on the DC-DC converter and charging circuit, since I have the cores for those, and plenty of IR2184s.
> 
> Anyone who wants the software or the plans for the circuit, or anything else, can just contact me.  (Please don't use my
> awmatt@mediaone.net, since it is going away tonight.  ComCrap hasn't been able to add me as a user yet, so just use
> fanofca@hotmail.com.)  This circuit would be workable for a simple open-loop AC induction motor controller - you could make a decent
> EV out of it.  I don't have any plans for my cooling plenum; I don't really feel like drawing it up, and it is quite customized for
> my project.  It's not really anything worth drawing up.  However, the circuit board design is done, and in AutoCAD 2000.
> 
> Note to Lee Hart: Thanks for the warning about the softening plastic - I have decided to get nylon washers and screws, which should
> prevent any softening.  I have already tried the washers, and they insulate very well and don't melt themselves.  Next time I'll try
> to find a material that won't soften as easily, but I'd like something see-through, if for no other reason but displaying it.
> 
> Just checking in,
> Arthur Matteson
> -- '80 Lectric Leopard
> -- Homebrew induction drive (soon)
> -- Ann Arbor, Michigan