Re gen on DC

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Re gen on DC

Mike Cook-3
Hi,
I have been following this exchange with some interest.  Is there some way you could post a sketch someplace where everyone could see it?  I've done a lot of work on the old GE EV-1 controllers on forklifts and was wondering how you could do regen with SCR controllers.

Mike

>Date: Wed, 28 Nov 2007 09:09:12 -0800
>From: "George Swartz" <[hidden email]>
>Subject: Re: [EVDL] Re gen on DC
>To: Electric Vehicle Discussion List <[hidden email]>
>Message-ID: <[hidden email]>
>Content-Type: text/plain; charset=iso-8859-1

>Jeff,  I will send you a private email with a sketch of the
>schematic.  I
>don't think I can attach it to the EVDL.

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Re: Re gen on DC

Jeff Major

Hi Mike,

It is George's property.  He was kind enough to send
it to me.  I wouldn't post it publicly without his
permission.  Not sure I know how to do that anyway.
Be advised that it is for sep-ex and the GE EV1 SCR
controllers were for series motors.  Cableform made
regen series SRC controllers way back when.  I have
one on my electric delivery Jeep.  Never did work
reliably.  Have it defeated now.  You might be able to
run across a Cableform schematic somewhere.

Regards,

Jeff M

--- Mike Cook <[hidden email]> wrote:

> Hi,
> I have been following this exchange with some
> interest.  Is there some way you could post a sketch
> someplace where everyone could see it?  I've done a
> lot of work on the old GE EV-1 controllers on
> forklifts and was wondering how you could do regen
> with SCR controllers.
>
> Mike
>
> >Date: Wed, 28 Nov 2007 09:09:12 -0800
> >From: "George Swartz" <[hidden email]>
> >Subject: Re: [EVDL] Re gen on DC
> >To: Electric Vehicle Discussion List
> <[hidden email]>
> >Message-ID: <[hidden email]>
> >Content-Type: text/plain; charset=iso-8859-1
>
> >Jeff,  I will send you a private email with a
> sketch of the
> >schematic.  I
> >don't think I can attach it to the EVDL.
>



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Re: Re gen on DC

George Swartz
Jeff,  My schematic is provided for the public domain.  David says he will
post it somewhere on EVDL.  There are several other features that I recall:  
The brake contactor adds a galvanic open circuit in the motor drive loop
when coasting, braking or idle stop.  This improves safety a little by
reducing fault paths of the motor full-on type that might launch an EV. The
charger used the chopper as a series switch and also used the motor
inductor.  It could be used single phase or three phase.   I used an
isolation transformer, but it was large and it was floor mounted and not on
the car.  I will try to remember the specific charge circuit.  I know that I
was super concerned not to have any motor fault paths that might provide
torque, etc. I also had a bypass contactor not shown on the simplified
schematic.  There were a lot of interlock circuits, I remember, and they
always worked well.



On Wed, 28 Nov 2007 11:52:50 -0800 (PST), Jeff Major wrote

> Hi Mike,
>
> It is George's property.  He was kind enough to send
> it to me.  I wouldn't post it publicly without his
> permission.  Not sure I know how to do that anyway.
> Be advised that it is for sep-ex and the GE EV1 SCR
> controllers were for series motors.  Cableform made
> regen series SRC controllers way back when.  I have
> one on my electric delivery Jeep.  Never did work
> reliably.  Have it defeated now.  You might be able to
> run across a Cableform schematic somewhere.
>
> Regards,
>
> Jeff M
>
> --- Mike Cook <[hidden email]> wrote:
>
> > Hi,
> > I have been following this exchange with some
> > interest.  Is there some way you could post a sketch
> > someplace where everyone could see it?  I've done a
> > lot of work on the old GE EV-1 controllers on
> > forklifts and was wondering how you could do regen
> > with SCR controllers.
> >
> > Mike
> >
> > >Date: Wed, 28 Nov 2007 09:09:12 -0800
> > >From: "George Swartz" <[hidden email]>
> > >Subject: Re: [EVDL] Re gen on DC
> > >To: Electric Vehicle Discussion List
> > <[hidden email]>
> > >Message-ID: <[hidden email]>
> > >Content-Type: text/plain; charset=iso-8859-1
> >
> > >Jeff,  I will send you a private email with a
> > sketch of the
> > >schematic.  I
> > >don't think I can attach it to the EVDL.
> >
>
>      
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Re: Re gen on DC

Jeff Major

Hello George,

In a private email to you I called your circuit
clever.  After some thought, I think elegant may be a
better descriptor.

The basic Jones chopper used as DC motor controllers
can be referred to as a quarter bridge, a switch and a
diode.  When going to a separately excited motor
control, one uses a half bridge (two switches) on the
armature and a full (or H) bridge on the field (2 half
bridges).  This makes sense when designing from
scratch.  Gives you regen, field weakening and
contactorless reversing.

However, if one would want to do a sep-ex motor
control using an existing high current controller
designed for series motors, like the Zilla, then your
circuit might be the key.  The 2000 amp Zilla isn't
cheap, and to make a full bridge version would likely
double the cost.  So your approach, needing only an
additional diode and contactor, would be attractive.

Add in the fact that your circuit could be used as a
battery charger, and it becomes more attractive.  How
many have contemplated a 2000 amp charger? :-)

Just some food for thought.  Again, I thank you for
sharing this with us.  I read hundreds and hundreds of
posts which are mundane and boring.  It is a real
pleasure to come across a truly interesting idea.

I had said earlier that your circuit worked, but I
would not do it that way.  Well, I am rethinking the
second part of that remark.

Regards,

Jeff M

--- George Swartz <[hidden email]> wrote:

> Jeff,  My schematic is provided for the public
> domain.  David says he will
> post it somewhere on EVDL.  There are several other
> features that I recall:  
> The brake contactor adds a galvanic open circuit in
> the motor drive loop
> when coasting, braking or idle stop.  This improves
> safety a little by
> reducing fault paths of the motor full-on type that
> might launch an EV. The
> charger used the chopper as a series switch and also
> used the motor
> inductor.  It could be used single phase or three
> phase.   I used an
> isolation transformer, but it was large and it was
> floor mounted and not on
> the car.  I will try to remember the specific charge
> circuit.  I know that I
> was super concerned not to have any motor fault
> paths that might provide
> torque, etc. I also had a bypass contactor not shown
> on the simplified
> schematic.  There were a lot of interlock circuits,
> I remember, and they
> always worked well.
>



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Re: Re gen on DC

mos6507-2
In reply to this post by Mike Cook-3
I did some looking but was unable to find any PM DC motors powerful enough for EV use although they are very popular with Ebikes.  These would be ideal I would think because they would not require a DC->AC inverter, correct?

----- Original Message ----
  - PM DC motor and regen controller



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Re: Re gen on DC

Morgan LaMoore
On Nov 29, 2007 1:42 PM, Glenn Saunders <[hidden email]> wrote:
> I did some looking but was unable to find any PM DC motors powerful enough for EV use although they are very popular with Ebikes.  These would be ideal I would think because they would not require a DC->AC inverter, correct?

Nope, they're brushed DC motors, so their brushes act as a mechanical inverter.

They're nice because the permenant magnets improve efficiency and
allow regen with a simpler circuit than SepEx. However, you don't have
field weakening like wound-field DC motors, so they have a torque
profile more like an AC motor than a DC motor. (I.E. less low-end
torque.)

-Morgan LaMoore

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Re: Re gen on DC

George Swartz
In reply to this post by Jeff Major

Jeff, Thanks, I feel better now.  We charged the flooded lead batteries at
about 200amps current limit for about 45 minutes which would be about a 70%
or 80% recharge.  Of course, the taper charge is 4 to 6 hours after that if
you have the time and patience.  I will try to reconstruct the charge
circuit diagram.

As I remember, the field transition time was about 200 msec, so this could
be an objectionable delay in traffic.  There was an armature interlock that
prevented field transition unless armature current was zero amps.  



On Thu, 29 Nov 2007 10:30:06 -0800 (PST), Jeff Major wrote

> Hello George,
>
> In a private email to you I called your circuit
> clever.  After some thought, I think elegant may be a
> better descriptor.
>
> The basic Jones chopper used as DC motor controllers
> can be referred to as a quarter bridge, a switch and a
> diode.  When going to a separately excited motor
> control, one uses a half bridge (two switches) on the
> armature and a full (or H) bridge on the field (2 half
> bridges).  This makes sense when designing from
> scratch.  Gives you regen, field weakening and
> contactorless reversing.
>
> However, if one would want to do a sep-ex motor
> control using an existing high current controller
> designed for series motors, like the Zilla, then your
> circuit might be the key.  The 2000 amp Zilla isn't
> cheap, and to make a full bridge version would likely
> double the cost.  So your approach, needing only an
> additional diode and contactor, would be attractive.
>
> Add in the fact that your circuit could be used as a
> battery charger, and it becomes more attractive.  How
> many have contemplated a 2000 amp charger? :-)
>
> Just some food for thought.  Again, I thank you for
> sharing this with us.  I read hundreds and hundreds of
> posts which are mundane and boring.  It is a real
> pleasure to come across a truly interesting idea.
>
> I had said earlier that your circuit worked, but I
> would not do it that way.  Well, I am rethinking the
> second part of that remark.
>
> Regards,
>
> Jeff M
>
> --- George Swartz <[hidden email]> wrote:
>
> > Jeff,  My schematic is provided for the public
> > domain.  David says he will
> > post it somewhere on EVDL.  There are several other
> > features that I recall:  
> > The brake contactor adds a galvanic open circuit in
> > the motor drive loop
> > when coasting, braking or idle stop.  This improves
> > safety a little by
> > reducing fault paths of the motor full-on type that
> > might launch an EV. The
> > charger used the chopper as a series switch and also
> > used the motor
> > inductor.  It could be used single phase or three
> > phase.   I used an
> > isolation transformer, but it was large and it was
> > floor mounted and not on
> > the car.  I will try to remember the specific charge
> > circuit.  I know that I
> > was super concerned not to have any motor fault
> > paths that might provide
> > torque, etc. I also had a bypass contactor not shown
> > on the simplified
> > schematic.  There were a lot of interlock circuits,
> > I remember, and they
> > always worked well.
> >
>
>      
_____________________________________________________________________________
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> with Yahoo Mobile. Try it now.  
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>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev

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Re: Re gen on DC

Jeff Major

Hi George,

Sorry to keep bothering you.  But I was wondering last
night, did you have a problem with the motor brushes
during charging?  Seems like passing current with a
stationary comm might be detrimental.  Or were you
using only the inductor and by-passing the motor
during charge?

I was kidding about a 2000 amp charge :-).  But 200
amps is pretty impressive.

And noticed that I said full bridge and meant half
bridge when speaking of using the Zilla.

Regards,

Jeff

--- George Swartz <[hidden email]> wrote:

>
> Jeff, Thanks, I feel better now.  We charged the
> flooded lead batteries at
> about 200amps current limit for about 45 minutes
> which would be about a 70%
> or 80% recharge.  Of course, the taper charge is 4
> to 6 hours after that if
> you have the time and patience.  I will try to
> reconstruct the charge
> circuit diagram.
>
> As I remember, the field transition time was about
> 200 msec, so this could
> be an objectionable delay in traffic.  There was an
> armature interlock that
> prevented field transition unless armature current
> was zero amps.  
>
>
>
> On Thu, 29 Nov 2007 10:30:06 -0800 (PST), Jeff Major
> wrote
> > Hello George,
> >
> > In a private email to you I called your circuit
> > clever.  After some thought, I think elegant may
> be a
> > better descriptor.
> >
> > The basic Jones chopper used as DC motor
> controllers
> > can be referred to as a quarter bridge, a switch
> and a
> > diode.  When going to a separately excited motor
> > control, one uses a half bridge (two switches) on
> the
> > armature and a full (or H) bridge on the field (2
> half
> > bridges).  This makes sense when designing from
> > scratch.  Gives you regen, field weakening and
> > contactorless reversing.
> >
> > However, if one would want to do a sep-ex motor
> > control using an existing high current controller
> > designed for series motors, like the Zilla, then
> your
> > circuit might be the key.  The 2000 amp Zilla
> isn't
> > cheap, and to make a full bridge version would
> likely
> > double the cost.  So your approach, needing only
> an
> > additional diode and contactor, would be
> attractive.
> >
> > Add in the fact that your circuit could be used as
> a
> > battery charger, and it becomes more attractive.
> How
> > many have contemplated a 2000 amp charger? :-)
> >
> > Just some food for thought.  Again, I thank you
> for
> > sharing this with us.  I read hundreds and
> hundreds of
> > posts which are mundane and boring.  It is a real
> > pleasure to come across a truly interesting idea.
> >
> > I had said earlier that your circuit worked, but I
> > would not do it that way.  Well, I am rethinking
> the
> > second part of that remark.
> >
> > Regards,
> >
> > Jeff M
> >
> > --- George Swartz <[hidden email]> wrote:
> >
> > > Jeff,  My schematic is provided for the public
> > > domain.  David says he will
> > > post it somewhere on EVDL.  There are several
> other
> > > features that I recall:  
> > > The brake contactor adds a galvanic open circuit
> in
> > > the motor drive loop
> > > when coasting, braking or idle stop.  This
> improves
> > > safety a little by
> > > reducing fault paths of the motor full-on type
> that
> > > might launch an EV. The
> > > charger used the chopper as a series switch and
> also
> > > used the motor
> > > inductor.  It could be used single phase or
> three
> > > phase.   I used an
> > > isolation transformer, but it was large and it
> was
> > > floor mounted and not on
> > > the car.  I will try to remember the specific
> charge
> > > circuit.  I know that I
> > > was super concerned not to have any motor fault
> > > paths that might provide
> > > torque, etc. I also had a bypass contactor not
> shown
> > > on the simplified
> > > schematic.  There were a lot of interlock
> circuits,
> > > I remember, and they
> > > always worked well.
> > >





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Re: Re gen on DC

George Swartz
Jeff,  You are right.  Passing high current through a stationary motor for a
long time will burn the brushes and commutator leading to subsequent rapid
brush wear and there is also a safety issue of developing motor torque from
residual magnetism or field controller fault.    The armature is a poor
inductor compared to the external smoothing inductor anyway.

I think if you move the smoothing inductor to the top side of the motor,
then add a power diode from the motor/inductor junction back to battery
positive, the charge circuit will work.  Main and brake contactors remain
open during charging.  I just don't remember the details such as the
precharge circuit which must be active for both initial drive and charge set
up because of the large electrolytic cap bank on the chopper input.

I don't think there will be any circulating current thru the motor.  
However, the brake diode can be changed to an SCR and switched on only for
the brake mode.  

Adding the charge function to achieve a 3 in 1 controller means that the
chopper must have a higher voltage rating.  This system can be operated off
line with no isolation transformer, however there are safety problems to be
looked at.  Higher voltage is less of a problem than reliable commutation at
low voltage. Another detail is that if the chopper SCR commutation energy
goes through the load, there will be a minimum charge current.  There are
some com circuits where com current does not flow through the load or where
com energy is from an outside source (class D) so that the chopper can work
reliably down to low voltages.  This is all antique stuff at this point in
time.

A single Zilla would work in this circuit. No commutation to have problems
with.   Note that some charger logic already exists in the controller
because of the regen function that must be restrained from overcharging a
fully charged battery:  for example, if you live at the top of a mountain.  

One thing I didn't mention before is that the boost regen becomes dynamic
braking  at low speeds when the chopper boost efficiency is low, and most
electrical brake energy is absorbed by resistance losses in the motor and
controller rather than being returned to the battery.  None the less,
electrical braking is strong down to 3mph.




On Fri, 30 Nov 2007 07:04:09 -0800 (PST), Jeff Major wrote

> Hi George,
>
> Sorry to keep bothering you.  But I was wondering last
> night, did you have a problem with the motor brushes
> during charging?  Seems like passing current with a
> stationary comm might be detrimental.  Or were you
> using only the inductor and by-passing the motor
> during charge?
>
> I was kidding about a 2000 amp charge :-).  But 200
> amps is pretty impressive.
>
> And noticed that I said full bridge and meant half
> bridge when speaking of using the Zilla.
>
> Regards,
>
> Jeff
>
> --- George Swartz <[hidden email]> wrote:
>
> >
> > Jeff, Thanks, I feel better now.  We charged the
> > flooded lead batteries at
> > about 200amps current limit for about 45 minutes
> > which would be about a 70%
> > or 80% recharge.  Of course, the taper charge is 4
> > to 6 hours after that if
> > you have the time and patience.  I will try to
> > reconstruct the charge
> > circuit diagram.
> >
> > As I remember, the field transition time was about
> > 200 msec, so this could
> > be an objectionable delay in traffic.  There was an
> > armature interlock that
> > prevented field transition unless armature current
> > was zero amps.  
> >
> >
> >
> > On Thu, 29 Nov 2007 10:30:06 -0800 (PST), Jeff Major
> > wrote
> > > Hello George,
> > >
> > > In a private email to you I called your circuit
> > > clever.  After some thought, I think elegant may
> > be a
> > > better descriptor.
> > >
> > > The basic Jones chopper used as DC motor
> > controllers
> > > can be referred to as a quarter bridge, a switch
> > and a
> > > diode.  When going to a separately excited motor
> > > control, one uses a half bridge (two switches) on
> > the
> > > armature and a full (or H) bridge on the field (2
> > half
> > > bridges).  This makes sense when designing from
> > > scratch.  Gives you regen, field weakening and
> > > contactorless reversing.
> > >
> > > However, if one would want to do a sep-ex motor
> > > control using an existing high current controller
> > > designed for series motors, like the Zilla, then
> > your
> > > circuit might be the key.  The 2000 amp Zilla
> > isn't
> > > cheap, and to make a full bridge version would
> > likely
> > > double the cost.  So your approach, needing only
> > an
> > > additional diode and contactor, would be
> > attractive.
> > >
> > > Add in the fact that your circuit could be used as
> > a
> > > battery charger, and it becomes more attractive.
> > How
> > > many have contemplated a 2000 amp charger? :-)
> > >
> > > Just some food for thought.  Again, I thank you
> > for
> > > sharing this with us.  I read hundreds and
> > hundreds of
> > > posts which are mundane and boring.  It is a real
> > > pleasure to come across a truly interesting idea.
> > >
> > > I had said earlier that your circuit worked, but I
> > > would not do it that way.  Well, I am rethinking
> > the
> > > second part of that remark.
> > >
> > > Regards,
> > >
> > > Jeff M
> > >
> > > --- George Swartz <[hidden email]> wrote:
> > >
> > > > Jeff,  My schematic is provided for the public
> > > > domain.  David says he will
> > > > post it somewhere on EVDL.  There are several
> > other
> > > > features that I recall:  
> > > > The brake contactor adds a galvanic open circuit
> > in
> > > > the motor drive loop
> > > > when coasting, braking or idle stop.  This
> > improves
> > > > safety a little by
> > > > reducing fault paths of the motor full-on type
> > that
> > > > might launch an EV. The
> > > > charger used the chopper as a series switch and
> > also
> > > > used the motor
> > > > inductor.  It could be used single phase or
> > three
> > > > phase.   I used an
> > > > isolation transformer, but it was large and it
> > was
> > > > floor mounted and not on
> > > > the car.  I will try to remember the specific
> > charge
> > > > circuit.  I know that I
> > > > was super concerned not to have any motor fault
> > > > paths that might provide
> > > > torque, etc. I also had a bypass contactor not
> > shown
> > > > on the simplified
> > > > schematic.  There were a lot of interlock
> > circuits,
> > > > I remember, and they
> > > > always worked well.
> > > >
>
>      
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> http://www.yahoo.com/r/hs
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