Power Limiting instead of Current Limiting

General topics and discussions about the VESC and its development.
BlakeCarmichael
Posts: 16
Joined: 06 Sep 2017, 12:12
Location: Florida
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Power Limiting instead of Current Limiting

Postby BlakeCarmichael » 06 Sep 2017, 12:18

Hi,

I am using a VESC from diyelectricskateboard on a 24 V BLDC motor that has a 177 Watt maximum power rating.
The battery I am using is a 24 V lithium ion which ranges from 21-29.75 V throughout its cycle.

Using the VESC and BLDC tool, I would like to limit the power consumption of the motor such that it never exceeds the 177 W rating.
The only option for this I have seen is to limit the current, but this causes problems as the battery voltage drops because a fixed current limit will reduce the maximum power output to the motor at lower voltages.

Is there a solution to this that I am overlooking?

Thanks for any help.
Blake

devin
Posts: 255
Joined: 08 May 2017, 01:55
Location: San Francisco, California, US
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby devin » 06 Sep 2017, 13:12


BlakeCarmichael
Posts: 16
Joined: 06 Sep 2017, 12:12
Location: Florida
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby BlakeCarmichael » 06 Sep 2017, 13:27

Ok, I need to do some reading on FOC.

But, I haven't had any success with running motor detection on this motor. The motor is permanently attached to a compressor and I think that may have something to do with why the motor detection is failing. Is this correct? I have tried adjusting the current, min erpm, and low duty values in the motor detection field.
Do I need to resolve the motor detection issue before I can make headway with FOC?

BlakeCarmichael
Posts: 16
Joined: 06 Sep 2017, 12:12
Location: Florida
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby BlakeCarmichael » 06 Sep 2017, 14:01


devin
Posts: 255
Joined: 08 May 2017, 01:55
Location: San Francisco, California, US
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby devin » 06 Sep 2017, 14:42


devin
Posts: 255
Joined: 08 May 2017, 01:55
Location: San Francisco, California, US
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby devin » 06 Sep 2017, 14:52

Blake, on second thought, yes you are correct, the battery amp limit should be 6.31A based on the 28v peak voltage because above stall speed, the 29.74 motor amps and 7.37A battery amps @ 28v will be equivalent to more than 177w
Last edited by devin on 06 Sep 2017, 14:56, edited 1 time in total.

BlakeCarmichael
Posts: 16
Joined: 06 Sep 2017, 12:12
Location: Florida
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby BlakeCarmichael » 06 Sep 2017, 14:55


devin
Posts: 255
Joined: 08 May 2017, 01:55
Location: San Francisco, California, US
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby devin » 06 Sep 2017, 14:57


BlakeCarmichael
Posts: 16
Joined: 06 Sep 2017, 12:12
Location: Florida
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby BlakeCarmichael » 06 Sep 2017, 15:02


Addy
Posts: 7
Joined: 10 Aug 2017, 17:56
Location: BC, Canada
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Re: Power Limiting instead of Current Limiting

Postby Addy » 06 Sep 2017, 16:19

Why not limit the motor current instead of battery current? Then it doesn't really matter what the battery voltage is.


[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Return to “General”

Who is online

Users browsing this forum: Bing [Bot] and 5 guests