endless sphere is a great place if you know whom you're talking to
you cannot feed torque (which is a purely mechanical unit)
with a motor controller (which is a purely electrical unit)
As simple as that.
I think I know what you mean, I think I even understand what Ted wanted to say (which is basically the same thing)
BUT that doesn't make it more "correct" surely it's the wrong terminology.
the gernalisation volt = rpm for example is simply WRONG for most motors on this Planet,
it's not even true for BLDC motors mostly.
And that's what I am complaining about..
speed or torque BASED controller there are NONE!
All regulate Amp (Power really.. but generally considered as Amp control...)
Most simple controllers don't care about anything and
just use the pedal signal as the ONLY input, no ramping no governing, no nothing.
since it's rather basic, they usually come with nothing but undervoltage protection to save the batpack from dying.
advanced controllers (well somewhat advanced)
come with an additional overvoltage protection to save the motor from being fried,
and some other "protection" circuits and code.. like overcurrent protection, brake signal (to turn off the motor once the brake is engaged) emergency switches and so on.
More advanced controllers add a ramp up sequence which allows "smooth take off"
and/or a governor code to the mix limiting the max power to a certain amount (say 80%)
even more advanced controllers are programmable (in which case you can set/reset the ramp up and limiting factors)
and the peak of those programmable controllers add further input signals,
like motor temperature, motor speed and current Amp draw.
And that's where your misconception starts.
They too just toggle the MosFETS on and off in a matter of split seconds,
switching the motor on and off (again in split seconds)
it's a square wave... hook your controllers up to an oscilloscope and you'll see the signal
Now, as I said.. yes..
some modulate on/off time using the rotational speed (what you and Ted call speed controllers)
as a comparator value
(ONLY! works on BLDC motors, or motors with known quantity of hall effect sensors)
the downside of that is.. max rotational speed is an unknown value!
keep in mind that controllers do NOT know the motor attached, some can test the motor attached, most don't dare to fire a 7kW motor just to know how fast it could turn
The same holds true for those that don't care about rotational speed (what you and Ted call Torque controllers)
they just don't re-modulate the signal based on rotational speed.
And here's the thing.. while surely all BLDC controllers do read the speed signal somehow (hall effect or back emf from disengaged coils)
IF they use that information for remodulating the Powersignal is SOLELY UP TO YOU on a programmable controller.
And thus... while OOTB there might be a differnce between the behavious or the two controllers,
after you set them up to your needs/likings and reprogrammed them accordingly,
there is no difference any longer.
Both will behave exactly the same way, both will put out the exact same signal (one signal might be messier than the other, one programming interface might be better than the other, sure.. but that's it)
And again NONE of those controllers ever control the voltage..
they always control the power (V*A)
it's a matter of misreading the information provided ..
since the signal is toggled at a very high rate (in the kHz) there is not much equipment to read the signal (an oscilloscope is the one thing I can think of)
a multimeter for example will not read the peak voltage .. especially not when the power out isn't set to 100%
thus it reads a drop in voltage (it's averaging over a small amount of time [a thousand times to long])
even Flukes tend to fail at that task more often than not.
And to sum it up..
a controller does NOT know the motor, neither it's peak rpm nor it's peak torque
peak rpm is dangerous to test (for the controller not knowing if it's save to ramp the motor all the way up)
peak torque is IMPOSSIBLE to test for the controller (since there's no dyno atttached)
And thus... it should never be called torque or speed based.
When you're over at endless sphere.. ask the guys who BUILD motor controllers,
not just the ones who BUY them about how they work.
Once you understand how a MosFET works and how it is toggled, you will surely understand what I'm trying to say.
'sid
