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Circuits Theory Examples. Newton-Raphson Method. Formula for one-dimensional case : . Series of successive solutions :. If the iteration process is converged , the limit is the solution of the equation f(x)=0. Multidimensional case :. where :. JACOBI AN MATRIX. ALGOR ITHM.
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Circuits TheoryExamples Newton-Raphson Method
Formula for one-dimensional case: Series of successive solutions: If the iteration process is converged , the limit is the solution of the equationf(x)=0.
Multidimensional case: where: JACOBIAN MATRIX
ALGORITHM STARTING POINT STEP 0 STEP 1 Calculate STEP 2 Solve the equation: find STEP 3 check STOP conditions If the current solution is not acceptable: GO TO 1
EXAMPLE of STOP PROCEDURE k=k+1 GOTO 1 No Yes No Yes STOP
Stop condition parameter • Stop condition parameter
Numerical EXAMPLES Example 1
Solve the following set of nonlinearequation using the Newton’s Method:
Starting point (first approximation): Calculate:
(1a) (1b) (1c)
(1a) (1b) (1c) Let us assume (1a) (1b) (1c)
Gauss elimination computer scheme STEP 1 ELIMINATE y1from b i c: Multiply by and add to 1b
Multiply by and add to 1c
New set : (2a) (2b) (2c) (2a) (2b) (2c)
Elimination scheme repeat for equations 2b i 2c: (2a) Multiply by add o 2c (2b) (2c)
(3a) (3b) (3c) (3a) (3b) (3c)
Back substitution part: Setting y3 to 3b: Multiply by add to 3b
Because It is the first calculated approximation of the solution. Next iterations form a converged series:
Example 2 Nonlinear circuit having two variables (node voltages)
e1 e2
Nodal equations: 1 2
We choose starting vector: Calculate:
Applying N-R scheme: where: hence:
STOP CRITERIA not satisfied: k=k+1:
Second NR iteration where: hence:
for k=7: where: hence:
Briefly about: Iterative models of nonlinear elements
Iterative NR model of nonlinear resistor (voltage controled)
From NR method: circuit
Example3 Newton-Raphson Iterative model method
e1 e2
1 2 1
1 2 2
1 2
1 2
For starting vector: • We calculate parameters of the models:
Linear equations for the first approximation: Solution for k=1
Second step Solution for k=2
Briefly about: Forward Euler Method (Explicit) Backward Euler Method (Implicit)
Forward Euler Method (Explicit) Backward Euler Method (Explicit)