VTB Model Builder Automatic Code Generation Tool

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VTB Model BuilderAutomatic Code Generation Tool
Jimena Bastos
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Topics

• RCM method
• Automatically building a RCM-based model
• New elements
• Input data types
• Model generation process
• Future trends

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The RCM method

• Device Definition
• Number of terminals
• Across variable
• Through variable
• Dynamic Equations for each terminal and internal
  node

Either linear or non-linear

• Time discretization
• Mapping to a DC network

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Automatically building a RCM-model

• Desired design automation using RCM-based models.

Parameters
Terminals
Viewables
Model Name
Model Equations
Model DLL
Tool Model builder
Input
Output
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New elements

• Porting to the new VTB model format
• The description is fully embedded in the text
  file (better project management)
• Possibility of applying Transfer Function
  description in Signal Coupling

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Input data types

• Circuit description
• Transfer Function (frequency domain)
• Set of first-order linear differential equations
• Set of first-order non-linear differential
  equations

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Circuit description

• The model equations are mapped by the user to a
  DC network provided a set of basic components.
• Using SPICE-like circuit description, the user
  writes the input .VTM file.

Resistance, Inductance, Capacitor Ideal Current
and Voltage Source Linear Controlled Sources
(VCVS, CCVS, VCCS, CCCS)
Differential Equations
VTM file
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An Example of Application

• The 3-phase induction motor

a11 (RsLr RrM2/Lr)/det L a31 MRr/Lr a13
M(Rr/Lr)/det L a33 Rr/Lr a14 ?M/det
L a34 ? det L LsLr M2 a42 a31 a22
a11 a43 a34 a23 a14 a44 a33 a24 a13
System of 5 dynamic equations
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Mapping equations to a DC circuit
pij are the elements of the Park Matrix
yij are the elements of the Inv. Park Matrix
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VTM file

• Accepts symbolic variables.
• Specifies model name, parameter and viewable
  names, number of terminals (thus, number of
  internal nodes)

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Using the tool for this example
Loads IndMotor3ph4.vtm
Loads Icon.hex Creates Conductance Matrix Creates
Through Vector
Generates IndMotor3ph.cpp Generates IndMotor3ph.h
Releases Model IndMotor3ph.vtm For VTB Library
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Input data types

• Circuit description
• Transfer Function (frequency domain)
• Set of first-order linear differential equations
• Set of first-order non-linear differential
  equations

The rest of the cases need an additional
step Map the equations to a circuit If we are
able to do this, we can create a .VTM Input file
from it (SPICE-like description)
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Transfer Function

• Behavioral modeling in the frequency domain
  (Laplace Transform H(s)).
• Map the TF to equivalent circuit structure.
• Generate .VTM Input File

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Block Diagram
Y(s)




bn-1
bn-2
b1
b0
Eout
U(s)
1/s
1/s
1/s
1/s

-
-
-
-
an-1
an-2
a1
a0
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TF equivalent circuit structure
(n3) nodes, n order of characteristic equation.
INPUT
1
3
Eout
U(t)
U(t)
-a0x1
-a1x2
-an-1xn

Rin
Rs 1
VCCS
OUTPUT
2
Y(t)
bmxn
bm-1xn-1
-b0x1
-b1x2

Rout 1
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TF equivalent circuit structure(cont)
xi
xi1
INTEGRATOR BLOCK
1/s
xn
x1
4
n3

Eout
Rn
Cn
x2
R1
C1
Ri 1 T? Ci 1 F
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Linear ODE
VTM file
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Non linear ODE
Taylor series
VTM file
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Model Generation Process
Input Data type?
Map to circuit

• T.F.
• L. ODE
• N.L. ODE

Circuit Description
Load .VTM Input File
Create icon using VIE
Load icon.hex
Create Conductance Matrix G And Through Vector B
Generate C Code
Compile C code
Release VTB Library object .vtm
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Future trends

• Enrich the list of available components
• Include non linear components (this is already
  partly possible)
• Include components with implicit characteristic.