Hi Jeremy,
That is interesting about throttle being used to control regen. Over the past 6 months I have been playing with throttle settings while in regen mode. I have been surprised at how much I can throttle "up" and still have the voltage reading steadily climb. Higher throttle setting (depending on boat sailing speed) definitely affords higher regen.
The reason I have been able to play with the regen is because of your most excellent tutoring on the Turnigy Wattmeter modification, which lives at the helm http://endless-sphere.com/forums/viewtopic.php?f=2&t=21976 Thanks again.
Mark
Santa Cruz
--- In electricboats@yahoogroups.com, "Jeremy" <jeremy_harris_uk@...> wrote:
>
> Some use the throttle to adjust the level of regen, some use a separate regen control and some only have fixed levels of regen, depending on the original application they were designed for. These things are rarely designed for boats, we're piggy-backing on controllers designed for things like electric cars, golf buggies, motorcycles etc. I've not played with the really big BLDC controllers, but the smaller ones I've used have either had throttle controlled regeneration (feels like engine braking on an electric vehicle, as lifting the throttle increases the level of regen), fixed regen (often programmable) which gives a set regen power level when the throttle is closed or a separate regen control, that works like a reverse throttle (i.e. more "throttle" gives greater regen power).
>
> They all tend to control regen power, rather than voltage, though, as the design is intended to provide vehicle braking, rather than controlled power generation.
>
> Jeremy
>
> --- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@> wrote:
> >
> > i would sort of assume that a good controller would therefore allow one to set the max regen voltage to be allowed and self adjust so as to attain that voltage? Â ... and that would result in the amps varying? Â ...and de-energizing the thing completely would bring all output to zero?
> >
> >
> > ________________________________
> > From: Jeremy <jeremy_harris_uk@>
> > To: electricboats@yahoogroups.com
> > Sent: Wednesday, September 14, 2011 8:32 AM
> > Subject: [Electric Boats] Re: ME0913 as a generator?
> >
> >
> > Â
> > Regen efficiency should be on a par with normal drive, as the motor and controller losses are pretty much the same. Regen works on these motors by the controller turning the motor into a switched mode boost converter, increasing the output voltage to match the demand, whereas normally the controller works as a buck mode converter, decreasing the output voltage from the battery to match the throttle setting.
> >
> > One advantage of the way regen works on these controllers is that you can get a much higher output voltage from the setup than you might expect from the rpm of the motor and the motor speed constant, Kv. It's quite possible to turn the motor at a 1/4 of it's maximum rpm yet get the full voltage out of the controller.
> >
> > Jeremy
> >
> > --- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@> wrote:
> > >
> > > I've been looking at the ME0913 as teamed up with a Kelly controller that does regen.  As compared to the motors power output what efficiency would one expect to get from a regen such as this?  If the controller/motor team provides a 90% efficiency would one reasonable expect the generation efficiency to be the same?
> > >
> > >
> > > ________________________________
> > > From: Jeremy <jeremy_harris_uk@>
> > > To: electricboats@yahoogroups.com
> > > Sent: Wednesday, September 14, 2011 1:53 AM
> > > Subject: [Electric Boats] Re: ME0913 as a generator?
> > >
> > >
> > > ÂÂ
> > > You can certainly use this BLDC/PMAC motor as a generator, but it will generate 3 phase AC, rather than DC.
> > >
> > > This is the same as a car alternator though (they are also three phase AC generators) so can be rectified to DC.
> > >
> > > The big problem with using any PM motor as a generator is that there is no easy means of controlling the output. A non-PM alternator is controlled by varying the small current that flows in the rotor, which varies the magnetic field strength and hence the output power. The field is fixed with a PM alternator, so you need an external regulator. This would work rather like the motor speed controller in reverse (taking uncontrolled power from the generator and providing a regulated output). An alternative is to use feedback from the generator output to control the motor that's driving it, via some sort of servo system. Some cheap gensets do this, they control the throttle on the motor to regulate the output.
> > >
> > > Jeremy
> > >
> > > --- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@> wrote:
> > > >
> > > > Would anyone have thoughts on the appropriateness of driving an ME0913 motor to use it as a DC generator?  Spin it up so as to get 96v out of it?
> > > >
> > >
> >
>
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