How do you vary the load parameter of the "RLC Series Load" Block during a simulation from the GUI?

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Conrad Sienkiewicz
Conrad Sienkiewicz on 18 Jun 2017
Commented: James M on 3 Apr 2018
So I've been trying to control the active power of a load from the GUI while the simulation is running with no avail. I've been trying the following code, which is written in a Matlab Function block in Simulink:
function EVL = VarLoad(t)
%Allow the use of functions for standalone code
coder.extrinsic('num2str'); %Maybe it takes strings?
Test_Power = [4000 ; 5000; 6000; 3000]; %Matrix with power values
persistent t_ref Cell;
if isempty(t_ref) %Initialize if time = 0
t_ref = 0;
Cell = 1;
if t >= t_ref+0.1 %If desired time has elapsed change cell
t_ref = t_ref+0.1; %Set the new reference time
Cell = Cell + 1; %Move onto the next cell
else %Don't change
t_ref = t_ref;
Cell = Cell;
EVL = Test_Power(Cell,1); %Set the power equal to the corresponding time
set_param('PV_MPPT_inv_bat_Final/Household Loads/Series RLC Load', 'ActivePower', 'EVL')
It seems that EVL doesn't update in the workspace as the code is running. Also, I was wondering if I am even allow to manipulate SimPowerSystems during a simulation? I understand you can manipulate gain blocks and such, but what about this block's power parameter? If not does anyone have a clue as to how I could model a variable load? Please help and thanks for your time!

Answers (1)

Vishal Neelagiri
Vishal Neelagiri on 22 Jun 2017
There is no way to directly modify Simscape parameter values during the simulation. There are two workarounds for this:
1) Create a custom Simscape component that would take an additional input through Simulink. This would enable you to specify the ActivePower parameter through a Simulink block and pass this value as an input to a custom Simscape component that you build. The following documentation link gives some detail about the workflow involved in creating a custom Simscape component:
2) Simscape Run-Time Parameter. You would also be able to utilize Simscape Run-Time Parameters to modify parameter values without recompiling. However, you would still not be able to change the value of a run-time configurable parameter during simulation. You can only change the value of a run-time configurable parameter when a simulation is stopped. Further detail about Simscape Run-Time Parameters can be found at the following page:

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