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I have some task to do:

Please write equations in Simulink and simulate the circuit elements connected in series RLC (it was the electrical!). Outputs of the system should be voltage on the capacitor and voltage across the resistor. Recalled a very polite, the equation of state has the form: ˙ x = Ax + Bu y = Cx + Du I only equation in this form will be considered appropriate. For example, a voltage boost circuit and a sinusoidal function Heaviside'a, and their sum. Results accumulate in a place accessible to Matlab. In Matlab to check the superposition principle. Repeat this operation for a non-zero initial conditions. Perform the frequency characteristics for frequencies near the resonant frequency for all combinations of input-output (it would be good to benefit from toolbox'a Control System), although this is not necessary. Frequency can be calculated only for this case and can be calculated based on any knowledge of the matrix A, B, C and D. The latter solution will scored higher.

I want to ask how matrixs A,B,C and D can look to solve this problem ? Who to get two output values from this (voltage on capicitor and resistor) ?

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I don't understand the statement of your task at all. If you'd care to make it readable, your question would have a much better chance of getting answered. – Marek Jan 2 '11 at 14:18
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I agree with Marek. I'm afraid I just don't understand what you're asking about. Please rewrite and I'll be happy to reopen this. – Noldorin Jan 2 '11 at 23:13

closed as not a real question by Sklivvz♦, Marek, Noldorin Jan 2 '11 at 23:13

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.

2 Answers

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It's fairly obvious that the equations you are describing are the equations governing a state machine. I could go through all of the equations to help produce it, but let me give you just a few pointers.

  1. The first equations doesn't care at all about the outputs of the system.
  2. Everywhere you have a differential, you need to have a state variable. That would include each of the LC components.
  3. You need to relate each of the LC components into something that is a component of other state variables.
  4. The second equation relates the state variables to your outputs.

There is a paper relating electrical components to state space here, you might take a look at it.

As far as modeling these in Matlab, you can use the ss command, I'll leave you to look up how to use it.

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I think matrix looks: A = [0, 1; -1/(L*C), -R/L] B = [0; 1/L] C = [0; -R] D = 0 But what with initial conditions ? And how to get voltage(on capicitor and resistor) from this ?

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