How to create a concave signal step/ramp in Simulink?

I'm not sure how to properly phrase my question, but my problem is the following:

I want to implement a step in a programmable three phase source, which I need to compare to the one of another program (RSCADFX). The problem is, I don't know how to model the signal in order to look like the following signal from RSCADFX:

To me it's almost concave looking, it's neither a step nor a ramp. How can I achieve this result in Simulink?

[Mathieu NOE]

hello

this looks to me like a sinewave (50 Hz) with amplitude modulation - which gives this shape of the signal envelop.

the envelop can be obtained by feeding a first order system (with appropriate time constant , guessed about 0.2/3 = 0.066 s approx from the picture) with a step signal (once at t= 0 upwards and once at t = 10 s downwards)

Answer 1

[Mathieu NOE]

hello again

attached a small demo simulink file

in blue I highlighted the first order system based on a simple recursive equation (out = a*in+(1-a)*out_old)

see Single Pole Recursive Filters for more infos

you need to run first these lines in a m script to initialize some variables

ts = 1e-3; % sampling rate

Fs = 1/ts; % sampling freq
time_constant = 0.066; %estimated system time constant 
fc = 1/(2*pi*time_constant);
a = 1-exp(-2*pi*fc/Fs); % a coefficient in 1st order recursive equation : out = a*in+(1-a)*out_old

[Jonas]

Thank you! That should work!

[Mathieu NOE]

My pleasure !