calculate output(y) from a state space model

Question

Rashmil Dahanayake 2013-12-30

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/111029-calculate-output-y-from-a-state-space-model

评论： Rashmil Dahanayake 2013-12-31

采纳的回答： Honglei Chen

在 MATLAB Online 中打开

I have defined a first order system in state space. How can I calculate Y matrix, if X matrix known

X'=Ax+Bu; Y=Cx;

I attempted to convert the system to a transfer function using tf command. Then can calculate output by y= tf * u The output matrix appears to be in tf data type. I would like to have y in the same data type as x. (full m file attached, following code is an extract of the state space portion)

%Filter Parameters
Lf= 8e-3;  % Inductance for output filter
Cf= 400e-6;  % Capacitance for output filter
% state space equations for LC filter
A=[zeros(3,3) eye(3)/(3*Cf) -eye(3)/(3*Cf); -eye(3)/Lf zeros(3,3) zeros(3,3);
eye(3,3)/Lload zeros(3,3) -eye(3)*Rload/Lload];    % systemmatrix
B=[zeros(3,3); eye(3)/Lf; zeros(3,3)];      % coefficient for thecontrol variable u
C=eye(9);       % coefficient for the output y
D=[zeros(9,3)];   % coefficient for the output y
Ks = 1/3*[-1 0 1; 1 -1 0; 0 1 -1];    % Conversion matrix to transform [iiAB iiBC iiCA] to [iiA iiB iiC]
%Transfer function for inverter output stage
sys= ss(A,B,C,D);
H=tf(sys);
% calculating filtered output
Y=H(1,1) * V_AB;