Watt Control Via Duty Cycle Control?

General topics and discussions about the VESC and its development.
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

Watt Control Via Duty Cycle Control?

Postby devin » 17 Sep 2017, 21:59

Last edited by devin on 18 Sep 2017, 05:23, edited 4 times in total.

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: Watt Control Via Duty Cycle Control?

Postby devin » 17 Sep 2017, 23:17

^I think I made a mistake & this is actually the correct formula:

-----------

Watt Control Via Duty Cycle Control?

-----------

Could it be possible to implement wattage control for desired electrical wattage at all physically possible RPMs via duty cycle control?

-----------

Where:

A=Battery Amps
B= Motor Amps
C=Duty Cycle
D= Present Back Emf V
E= Effective PWM Voltage
F= Winding Resistance
G= Pack Voltage
H= Desired Wattage
I= Motor KV
J= Present RPM

A=H/G
&
D=(1/I)*J
&
E=(1/2)(sqrt((4AFG)+D^2)+D)
&
C=(E/G)*100
&
B=A/(C/100)
&
%throttle=%H
or (option)
%throttle=%B

Will post explanation shortly...
Last edited by devin on 18 Sep 2017, 06:46, edited 2 times in total.

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: Watt Control Via Duty Cycle Control?

Postby devin » 18 Sep 2017, 04:12


pf26
Posts: 310
Joined: 28 Mar 2016, 14:37
Location: FR Valence
[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: Watt Control Via Duty Cycle Control?

Postby pf26 » 18 Sep 2017, 13:22

With A= 10A = Battery Amps, B= 50A = Motor Amps, C= 20% = Duty Cycle, D= 5V = Present Back Emf V, E= 10V = Effective PWM Voltage
F= 0.1ohm = Winding Resistance, G= 50V = Pack Voltage, H= 500W = Desired Wattage, I= 100kv = Motor KV, J= 500rpm = Present RPM
It seems like half of your 500W is lost in the winding resistance. That's less than 50% efficiency...
So it is worth mentionning that the desired wattage is at the battery, and not at the motor output.

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: Watt Control Via Duty Cycle Control?

Postby devin » 18 Sep 2017, 14:49


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: Watt Control Via Duty Cycle Control?

Postby devin » 18 Sep 2017, 18:35

Last edited by devin on 18 Sep 2017, 19:56, edited 2 times in total.

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: Watt Control Via Duty Cycle Control?

Postby devin » 18 Sep 2017, 19:36

Last edited by devin on 18 Sep 2017, 21:30, edited 1 time in total.

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: Watt Control Via Duty Cycle Control?

Postby devin » 18 Sep 2017, 20:21


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: Watt Control Via Duty Cycle Control?

Postby devin » 18 Sep 2017, 20:39


pf26
Posts: 310
Joined: 28 Mar 2016, 14:37
Location: FR Valence
[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: Watt Control Via Duty Cycle Control?

Postby pf26 » 19 Sep 2017, 12:25

Watt control from the battery is already implemented, since you can configure a limitting max battery current, and the battery voltage should be very stable.
If you give enough throttle, the duty cycle and motor current will be determined by the max battery current, ie watt-control.
It might be interesting to have the throttle control the battery max current parameter instead of duty cycle or motor current. It should be quite easy to create a custom app doing this.


[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: No registered users and 4 guests