How should the VESC "feel" on a board?

General topics and discussions about the VESC and its development.
arvidb
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Re: How should the VESC "feel" on a board?

Postby arvidb » 10 May 2017, 07:28


benjamin
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Re: How should the VESC "feel" on a board?

Postby benjamin » 10 May 2017, 07:33


devin
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Re: How should the VESC "feel" on a board?

Postby devin » 10 May 2017, 11:26


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Re: How should the VESC "feel" on a board?

Postby devin » 10 May 2017, 14:22

In the future I would love to see a watt control mode implemented as follows:

1- user selects electrical wattage, for example "500w," equivalent to 500w electrical full throttle at all physically possible rpms

2- based on chosen wattage, battery amp limit and motor amp limit are chosen automatically based on detected winding resistance and pack voltage. the battery limit would have to change dynamically with fluctuating pack voltage to achieve this while the motor amp limit setting would remain constant.

3. user experiences full throttle = 500w electrical equivalence at all physically possible rpms, even during voltage sag

benjamin
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Re: How should the VESC "feel" on a board?

Postby benjamin » 10 May 2017, 17:03


devin
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Re: How should the VESC "feel" on a board?

Postby devin » 10 May 2017, 17:25

Let's imagine a motor controller that is programmed to the following:

full throttle = 10 battery amps at all physically possible rpms

(current control)

(50v pack voltage assumed - 500w is desired)

full throttle = 10 battery amps x 50v = 500w at all physically possible rpms (with no sag)

if sag brings pack v to 46v under load:

full throttle = 10 battery amps x 46v = 460w at all physicslly possible rpms (40w loss electrical from 500w desired)

if battery amp limit of the controller was programmed to fluctuate dynamically to maintain 500w electrical

when v sag to 46v occurs:

full throttle = 10.86 battery amps at all physically possible rpms (10.86 battery amps x 46v pack sag = 500w electrical desired)

devin
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Re: How should the VESC "feel" on a board?

Postby devin » 10 May 2017, 17:31

if the winding resistance detection was 0.0415ohm x 2 = 0.0830ohm, and the motor amp limit was set to 77.61 motor amps, then 500w and 10 battery amps would be "allowed" to occur at full throttle, even close to 0rpm

in this theoretical battery current control esc, if the motor amp limit is set below 77.61 motor amps, then 10 battery amps would be impossible at rpms close to but still above 0rpm because 500w and therefore 10 battery amps would be "forbidden" by the lowered motor amp limit.

devin
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Re: How should the VESC "feel" on a board?

Postby devin » 10 May 2017, 17:44

for example if motor amp limit were set to "40" with the 0.0415ohm x 2 = 0.0830ohm winding

40 motor amps limit only "allows" 132.8watts close to 0rpm full throttle (40 motor amps x 3.32v pwm effective volts = 132.8w)

132.8watts / 50v battery volts = 2.65 battery amps

therefore with a battery current control esc, desired 10 battery amps all possible rpms full throttle, desired 500w (50v), with 10 battery amp limit, and 40 motor amp limit settings, the most battery amps possible accelerating full throttle at rpms close to 0rpm is 2.65 battery amps or 132.8 watts electrical which is nowhere near the 10 battery amps & 500w desired or expected at all rpms full throttle.

77.61 motor amps limit "allows" 500watts close to 0rpm full throttle (6.44v effective pwm volts) and therefore 10 battery amps for current control = 10 battery amps full throttle at all possible rpms

77.61 motor amps limit x 6.44v effective volts = 500w
10 battery amps limit x 50v pack volts no sag = 500w
40 motor amps limit x 3.32v effective volts = 132.8w
2.65 battery amps x 50v pack volts no sag = 132.8w

benjamin
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Re: How should the VESC "feel" on a board?

Postby benjamin » 10 May 2017, 18:54

What exactly are you trying to achieve? Was it not acceleration that feels even? I get the feeling that you are completely ignoring what I'm writing...

hexakopter
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Re: How should the VESC "feel" on a board?

Postby hexakopter » 10 May 2017, 18:58

Please stop it devin. You are continuing the nonsense threads/discussions you already started on the electric-skateboard forum.
You are just ignoring what the people tell you and steel their time with talking about "XXXw at all physically possible rpms", also they told you x times before that this isn't useful. Benjamin has make an effort to explain it to you, but you are just ignoring it with your hardheaded opinion.
I think it isn't unfounded that you got banned on the electric-builders forum. Please dont do it here again. :|
Because you already created your own forum especially for this topic, maybe it would be a good idea to discuss it there.


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