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by rew
13 Oct 2017, 07:50
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 108
Views: 8236

Re: "Peak Efficiency" Control Mode?

they also want highest possible range and electrical to mechanical conversion efficiency while repeatedly accelerating at full throttle during their start-and-stop morning commute. Should I recommend "efficiency control" or the "classical algorithm" to achieve this customer's re...
by rew
09 Oct 2017, 07:26
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 108
Views: 8236

Re: "Peak Efficiency" Control Mode?

You suggest that while I command 50A of motor current through the throttle, I would accept getting only 0.8A. Well, I don't. I think most people would agree that such a big difference is unacceptable. The general idea is that the more throttle you use, the worse the efficiency becomes. At low speeds...
by rew
08 Oct 2017, 09:10
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 108
Views: 8236

Re: "Peak Efficiency" Control Mode?

So, I managed to find a situation, a not so theoretical example, where you fail to reach the "desired efficiency" by getting a much higher efficiency. Now I'm going come up with an example where you fail to reach the desired efficiency by coming short a long ways.... Same motor, but now we...
by rew
08 Oct 2017, 08:21
Forum: General
Topic: Strange behaviour on Regen mode
Replies: 10
Views: 1104

Re: Strange behaviour on Regen mode

Hi all, Does anyone knows if there is a hardware protection for over-voltage that can switch the VESC off ? I don't think there is a hardware protection for over voltage. Things just blow up if you really exceed the tolerances of the components. Someone here suggested that it might be the diode tha...
by rew
08 Oct 2017, 08:13
Forum: VESC Projects
Topic: High RPM rc motor for Ebike
Replies: 5
Views: 526

Re: High RPM rc motor for Ebike

In theory that motor has a torque constant of 0.018 Nm/A. At 100A that would be 1.8Nm. Multiply that by 45 and you get 81Nm at the wheels. A 20" wheel has .25m radius, so that would provide you with 320N of "thrust" at the wheels. Not unreasonable.
by rew
03 Oct 2017, 07:41
Forum: General
Topic: Emergency braking concept for VESC
Replies: 40
Views: 8656

Re: Emergency braking concept for VESC

As far as I know, that's already implemented. If you don't want the VESC assisting in braking but just cutting power when you activate the switch (*), you should set the max battery reverse current very low. (*) Just call it a switch, the fact that it is hall-sensor based does not matter in this case!
by rew
03 Oct 2017, 07:37
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 108
Views: 8236

Re: "Peak Efficiency" Control Mode?

Just a quick question. Say I have a 50V motor, currently running at 25V BEMF. Suppose the motor can do 50A, but the torque required is only 5A. The motor has 20mOhm resistance. What is the effective voltage that you propose and what is the efficiency of the motor? (the last example that I read, and ...
by rew
03 Oct 2017, 07:31
Forum: FOC
Topic: FOC poor efficiency at high speed
Replies: 20
Views: 1778

Re: FOC poor efficiency at high speed

If you can, try "compiling firmware" and "uploading firmware" before you start changing the hardware.
by rew
01 Oct 2017, 09:10
Forum: FOC
Topic: FOC poor efficiency at high speed
Replies: 20
Views: 1778

Re: FOC poor efficiency at high speed

yes!
by rew
01 Oct 2017, 09:09
Forum: General
Topic: Emergency braking concept for VESC
Replies: 40
Views: 8656

Re: Emergency braking concept for VESC

Hall sensors are not able to assist in breaking. As the word "sensor" says they sense something. They are not active. In order to brake, all you need is to rectify the phases from the motor and use a variable resistor to load the resulting (not quite) DC. You don't need to disconnect the V...

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