[Scilab-users] Modelling dynamic systems with real world data

[Michael J McCann]

Hmm... batteries: Charge storage devices which have a largely constant 
voltage in the working range but which show big changes in apparent 
voltage when they reach full charge and when the charge drops very low. 
You don't get all the electrons back. I suspect a really good model 
would relate these effects to the electrochemical processes at work. 
Also because they are "batteries" and not individual cells,  the 
aggregate behaviour will depend on the whole (in series) set.
With a sort of diodes and resistors model for the charge and discharge 
routes (somewhat different characteristics), it is possible to make a 
fair model for a battery's functional operations but I'd be a bit 
concerned if it was to try to make predictions of behaviour under 
stress  (e.g.very high discharge rates) or temperature changes (which in 
lead acid batteries reduce apparent capacity and ability to deliver 
current). There's an industry emerging for batteries with all the 
associated support equipment for creating backups for solar power etc.
So it becomes a question of how deep you want to go into the physics.

Mike.

=====================
On 12/04/2017 16:02, tim at wescottdesign.com wrote:
>
> I strongly suspect that anything that would be useful would be 
> specific to batteries, and would perhaps be best done in batch mode to 
> generate a model that is then hand-tweaked and selected for use in 
> xcos -- but I say that in part because over the years I've come to 
> dislike graphical solvers.
>
> I think it's possible to build a subsystem out of blocks that can be 
> "masked" so that you can enter parameters in the usual way -- if you 
> could boil your battery model down so that it had a few parameters, 
> you could translate your measured data into parameters once, then use 
> parameterized blocks for the battery behavior.
>
> On 2017-04-12 07:49, phillip mobley wrote:
>
>> Sure thing Tim,
>> Thank you for pointing out those details. I will share as much as I can.
>> I am simulating the behavior of a battery as it is discharging into a 
>> circuit. I recorded data from the battery (for example, the voltage 
>> and current and internal resistance) during testing. I currently have 
>> the data at different time steps inside of an excel file.
>> I would like to test this battery under different circuit 
>> configurations. However, changing the circuit can be time consuming 
>> and expensive. I was thinking that I could use xcos ability to do 
>> circuit simulation to construct a basic model of the battery that I 
>> am using that utilizes the data that I gathered. This way I can 
>> simulation the battery under different circuit configurations very 
>> easily.
>> So I was wondering if there was a way that I could import my data 
>> into xcos to construct a model for simulation.
>> I actually created the system to simulate the battery.
>>
>> On Tue, Apr 11, 2017 at 3:48 PM, Tim Wescott <tim at wescottdesign.com 
>> <mailto:tim at wescottdesign.com>> wrote:
>>
>>     "Simulate the data"?
>>
>>     Surely you mean you wish to simulate the system which was used in the
>>     measurement!
>>
>>     You don't give much detail, but I suspect that what you want to do is
>>     to develop a model of the system that fits the experiment, and
>>     then use
>>     that model in your simulations.
>>
>>     The general term for generating the model is called "system
>>     identification", but that covers a pretty broad swath.
>>
>>     Can you share the test you did, the sort of data you collected, the
>>     sort of system you're trying to model, and how well you know the
>>     system
>>     itself?
>>
>>     On Tue, 2017-04-11 at 15:10 -0400, phillip mobley wrote:
>>     > Hello all,
>>     >
>>     > I have some data from a test that I preformed. I was looking to
>>     > simulate this data under different conditions and I was
>>     wondering if
>>     > there is a palette in xcos that would allow me to input data (maybe
>>     > from an excel spreadsheet or copy paste) in order to use in the
>>     > simulation?
>>     >
>>     > Is this possible with xcos?
>>     > _______________________________________________
>>     > users mailing list
>>     > users at lists.scilab.org <mailto:users at lists.scilab.org>
>>     > http://lists.scilab.org/mailman/listinfo/users
>>     <http://lists.scilab.org/mailman/listinfo/users>
>>     --
>>
>>     Tim Wescott
>>     www.wescottdesign.com <http://www.wescottdesign.com>
>>     Control & Communications systems, circuit & software design.
>>     Phone: 503.631.7815 <tel:503.631.7815>
>>     Cell: 503.349.8432 <tel:503.349.8432>
>>
>>
>>
>>     _______________________________________________
>>     users mailing list
>>     users at lists.scilab.org <mailto:users at lists.scilab.org>
>>     http://lists.scilab.org/mailman/listinfo/users
>>     <http://lists.scilab.org/mailman/listinfo/users>
>>
>
>
>
> _______________________________________________
> users mailing list
> users at lists.scilab.org
> http://lists.scilab.org/mailman/listinfo/users

-- 
Dr.M.J.McCann,MJMcCann-Consulting

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.scilab.org/pipermail/users/attachments/20170413/36ddcec5/attachment.htm>