Simulink Control Design™ - MathWorks

(Tuis.) #1

slLinearizer linearization interface for "scdcascade":


No analysis points. Use the addPoint command to add new points.
No permanent openings. Use the addOpening command to add new permanent openings.
Properties with dot notation get/set access:
Parameters : []
OperatingPoints : [] (model initial condition will be used.)
BlockSubstitutions : []
Options : [1x1 linearize.LinearizeOptions]


Vary Inner-Loop Controller Gains


For inner-loop analysis, vary the gains of the inner-loop PI controller block, C2. Vary the
proportional gain (Kp2) and integral gain (Ki2) in the 15% range.


Kp2_range = linspace(Kp20.85,Kp21.15,6);
Ki2_range = linspace(Ki20.85,Ki21.15,4);
[Kp2_grid, Ki2_grid] = ndgrid(Kp2_range,Ki2_range);


params(1).Name = 'Kp2';
params(1).Value = Kp2_grid;
params(2).Name = 'Ki2';
params(2).Value = Ki2_grid;


sllin.Parameters = params;


Kp2_range and Ki2_range specify the sample values for the Kp2 and Ki2 parameters.
To obtain a transfer function for each combination of Kp2 and Ki2, you use ndgrid and
construct a 6x4 parameter grid, with grid arrays Kp2_grid and Ki2_grid. You configure
the Parameters property of sllin with the structure params. This structure specifies
the parameters to be varied and their grid arrays.


Analyze Overall Closed-Loop Transfer Function for Inner Loop


The overall closed-loop transfer function for the inner loop, with the outer loop open, is
equal to the transfer function from u1 to y2. To eliminate the effects of the outer loop,
break the loop at e1, y1m, or y1. For this example, break the loop at e1.


Add u1 and y2 as analysis points, and e1 as a permanent opening of sllin.


addPoint(sllin,{'y2','u1'});
addOpening(sllin,'e1');


Obtain the transfer function from u1 to y2.


Batch Linearization to Obtain Multiple Transfer Functions for Varied Parameter Values
Free download pdf