Difference between revisions of "Lecture 4. - Assignment"

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| width=50% |
 
| width=50% |
 
'''Instructor'''
 
'''Instructor'''
−
* Dániel Marcsa (lecturer)
+
* [http://wiki.maxwell.sze.hu/index.php/Marcsa Dániel Marcsa] (lecturer)
 
* Lectures: Monday, 14:50 - 16:25 (D201), 16:30 - 17:15 (D105)
 
* Lectures: Monday, 14:50 - 16:25 (D201), 16:30 - 17:15 (D105)
 
* Office hours: by request
 
* Office hours: by request
Line 22: Line 22:
 
* Office hours: -.
 
* Office hours: -.
 
|}
 
|}
−
 
+
<blockquote>
 
=== Purpose of the Assignment ===
 
=== Purpose of the Assignment ===
−
[[File:Lecture4 ProblemGeometry.png|500px|thumb|right|alt=The geometry of the problem with the yellow cable harness. | The geometry of the problem with the yellow cable harness.]]
+
[[File:Lecture4 ProblemGeometry.png|510px|thumb|right|alt=The geometry of the problem with the yellow cable harness. | The geometry of the problem with the yellow cable harness.]]
  
 
The student will learn the main steps of the finite element method, such as preparing the model (creating or importing geometry), specifying material parameters, boundary conditions, and excitation through a full-wave problem. This example gives a brief insight into the cable harness analysis through an automotive example.
 
The student will learn the main steps of the finite element method, such as preparing the model (creating or importing geometry), specifying material parameters, boundary conditions, and excitation through a full-wave problem. This example gives a brief insight into the cable harness analysis through an automotive example.
Line 35: Line 35:
 
=== Steps to solve the problem ===
 
=== Steps to solve the problem ===
 
After launching ANSYS Electronics Desktop, open the file '''CableHarness_Example.aedt''' using the ''File <math> \to </math> Open'' menu. <br/>
 
After launching ANSYS Electronics Desktop, open the file '''CableHarness_Example.aedt''' using the ''File <math> \to </math> Open'' menu. <br/>
−
To use '''ANSYS 2D Extractor''', '''ANSYS HFSS''' and '''ANSYS Circuit''', the ''Help'' menu and ''YouTube'' videos provide a lot of help.
+
To use [https://www.ansys.com/products/electronics/ansys-q3d-extractor ANSYS 2D Extractor], [https://www.ansys.com/products/electronics/ansys-hfss ANSYS HFSS] and [https://www.ansys.com/products/electronics/ansys-electronics-desktop ANSYS Circuit], the ''Help'' menu and ''YouTube'' videos provide a lot of help.
−
 
+
</blockquote>
−
== Defining the Problem ==
+
== Problem Definition and Results ==
−
[[File:PMMotor FEMMesh.png|360px|thumb|left|alt=A possible discreatization of the problem. | A possible discreatization of the problem.]]
+
<blockquote>
 +
[[File:Cable Evectors.gif|360px|thumb|right|alt=Electric field intensity vectors in the dielectric material in ''ANSYS 2D Extractor''. |Electric field intensity vectors in the dielectric material in ''ANSYS 2D Extractor'' <span style="color:blue">[Click to see animation.]</span>.]]
 +
[[File:CableHarness Circuit.png|360px|thumb|right|alt=The driving circuit of cable in ''ANSYS Circuit''. | The driving circuit of cable in ''ANSYS Circuit''.]]
 +
In this case, the whole problem is pre-defined. The reason for this is to avoid lengthy setup and basically, the purpose of the example is to look at the effect of high-frequency cables for the car body. Thanks to this example, students explain why you need to pay attention to the proper cable routing in vehicles. However, we review the structure of this task.
  
−
In this case, the geometry and definitions/settings of the problem are pre-defined. The reason for this is to avoid lengthy setup and basically, the purpose of the example is to look at sources of unwanted phenomena (force, loss) as an example of a rotating electric machine.
+
The problem is split into three parts:
 +
* The analysis of cable (''ANSYS 2D Extractor'');
 +
* the set up of cable harness electric circuit (''ANSYS Circuit'');
 +
* and the high-frequency analysis of the car body with cable harness (''ANSYS HFSS'').
  
 
Before and during the run, we briefly review the settings of the problem.
 
Before and during the run, we briefly review the settings of the problem.
Line 46: Line 52:
 
It is important to note that in the previous two examples, adaptive meshing used. However, in the case of a time-dependent (transient) problem, it is not possible to use the adaptive mesh, so we need to define the discretization of the problem with different mesh operations.
 
It is important to note that in the previous two examples, adaptive meshing used. However, in the case of a time-dependent (transient) problem, it is not possible to use the adaptive mesh, so we need to define the discretization of the problem with different mesh operations.
  
−
== Sett up the solver, run the simulation ==
+
=== Analysis of Cable Parasitics (''ANSYS 2D Extractor'') ===
−
 
 
−
At the solver, the end of the time interval of calculation should be defined as well as the time step. In this example, the end time is 15 ms (''Stop time'') and 0.05 ms (100 time steps per period) is the ''time step''.
 
  
−
You may also need to set the nonlinear solver, because the <math> {B} - {H} </math> relation of the stator and rotor steel is nonlinear. In this case, the relative permeability is space dependent, as you can see in Fig. 1.
+
ANSYS 2D Extractor efficiently performs the 2D quasi-static electromagnetic field simulations (''ANSYS Q3D Extractor for 3D problems'') required for the extraction of RLCG parameters (''R'' - resistance, ''L'' - inductance, ''C'' - capacitance, ''G'' - conductance) from an interconnect structure.
  
−
In order to plot the result at several time instants, it is necessary to specify in which time step we want to save the solution. If we do not do this, the last time step is saved automatically, so the field quantities (<math>\vec{A}; \vec{B}; \vec{H}</math>; ...) or other derived quantities (<math> \text{loss}, \text{energy}, ... </math>) can be plot in this instance.
+
As you can see in the figure, the cable has positive, negative and return veins. The veins wrapped by insulation and the outer sheath.
  
−
== Evaluation of results ==
+
The simulation frequency is 300 MHz and the result of the analysis is shown in the following tables.  
−
The purpose of this example is to illustrate the source of undesirable phenomena in electric machines. The source of the heat is the loss in the various parts of the machine. We have already met with the eddy current loss in the previous lecture. However, the so-called [https://en.wikipedia.org/wiki/Electrical_steel electric steels] has more components for core loss
 
  
−
::<math> p_{\text{vas}} = p_{\text{h}} + p_{\text{c}} + p_{\text{e}} = K_{\text{h}}f(B_{\text{max}})^2 + K_{\text{c}}(f B_{\text{max}})^2 + K_{\text{e}}(f B_{\text{max}})^{1.5} </math>,
+
{| width=60%
−
 
 
−
where <math>p_{\text{h}}</math> is the hysteresis loss, <math>p_{\text{c}}</math> is the eddy current loss, <math>p_{\text{e}}</math> is the excess loss, <math>K_{\text{h}}, K_{\text{c}}, K_{\text{e}}</math> is the coefficient of losses, <math>f</math> is the frequency and <math>B_{\text{m}}</math> is the maximum of magnetic flux density. Fig. 1 shows the core loss and its components as a function of time.
 
−
 
 
−
The other main undesirable phenomenon is the vibration of electric machines. Here, we only deal with the main electromagnetic source of the vibration, the air-gap flux density, which differs from pure sinus, so it has harmonic content (harmonic content hardly depend on the design of machine). According to the Maxwell stress tensor, the tensile force (radial force magnitude) acting on the stator and on the rotor surface is proportional to the square of the normal component of the air-gap flux density. The Maxwell stress tensor can be calculated with the following relationship
 
−
 
 
−
::<math>\vec{\sigma} =  \frac{1}{\mu_0}\left(\vec{B}\cdot\vec{n}\right)\vec{B} - \frac{1}{2\mu_0}B^2\vec{n}</math>,
 
−
 
 
−
where <math>B = \|\vec{B}\|</math> is the absolut value of magnetic flux density. Fig. 3 shows the force acting on the stator teeth.
 
−
{| width=100%
 
 
|-
 
|-
 
| align=center |
 
| align=center |
−
[[Image:PMMotor CoreLossResults.png|450px]]
+
{| class = "wikitable" style = "text-align: center; width: 300px; height: 100px;"
 +
|+ Conductance matrix of cable.
 +
! Conductance [<math>\mu\text{S}</math>]
 +
! Negative
 +
! Positive
 +
|-
 +
! Negative
 +
| 48.46 || -24.23
 +
|-
 +
! Positive
 +
| -24.23
 +
| 48.46
 +
|}
 
| align=center |
 
| align=center |
−
[[File:PMMotor RelativePermeability.png|300px]]
+
{| class = "wikitable" style = "text-align: center; width: 300px; height: 100px;"
 +
|+ Capacitance matrix of cable.
 +
! Capacitance [<math>\mu\text{F}</math>]
 +
! Negative
 +
! Positive
 +
|-
 +
! Negative
 +
| 117.269 || -58.634
 +
|-
 +
! Positive
 +
| -58.634
 +
| 117.268
 +
|}
 +
|-
 +
| align=center |
 +
{| class = "wikitable" style = "text-align: center; width: 300px; height: 100px;"
 +
|+ Resistance matrix of cable.
 +
! Resistance [<math>\Omega</math>]
 +
! Negative
 +
! Positive
 +
|-
 +
! Negative
 +
| 1.912 || 0.941
 +
|-
 +
! Positive
 +
| 0.941
 +
| 1.895
 +
|}
 
| align=center |
 
| align=center |
−
[[File:PMMotor EdgeForce.gif|300px]]
+
{| class = "wikitable" style = "text-align: center; width: 300px; height: 100px;"
 +
|+ Inductance matrix of cable.
 +
! Inductance [<math>\mu\text{H}</math>]
 +
! Negative
 +
! Positive
 +
|-
 +
! Negative
 +
| 0.134 || 0.067
 
|-
 
|-
−
|align=center | <span style="font-size:88%;">''' ''Fig. 1'' - The core loss and its components in the function of time.'''</span>
+
! Positive
−
|align=center | <span style="font-size:88%;">''' ''Fig. 2'' - The relative permeability in the stator and rotor core.'''</span>
+
| 0.067
−
|align=center | <span style="font-size:88%;">''' ''Fig. 3'' - The variation of teeth force as a function of time.'''</span> <span style="font-size:80%;color:blue">[Click to see animation.]</span>
+
| 0.134
 +
|}
 
|}
 
|}
 +
 +
=== Driving Circuit of Cable Harness (''ANSYS Circuit'') ===
 +
[[File:CableHarsness EField.gif|510px|thumb|right|alt=The electric field intensity in the wire and in the car body in ''ANSYS HFSS''. | The electric field intensity in the wire and in the car body in ''ANSYS HFSS''. <span style="color:blue">[Click to see animation.]</span>]]
 +
The return path is grounded, while a port with 50<math>\Omega</math> terminal impedance is defined for the negative and positive conductor. The parasitic parameters of the cable veins are coming from the 2D Extractor simulation. The results of this circuit simulation are used as the excitation of finite element simulation in HFSS.
 +
 +
The excitation of the two non-grounded wires of the cable is sinusoidal. The amplitude of sine excitation is 0.5V, and the phase difference between negative and positive wires is 180 degree.
 +
 +
=== Car Body with Cable Harness (''ANSYS HFSS'') ===
 +
 +
ANSYS HFSS (''High Frequency Structure Simulator'') is a 3D electromagnetic simulation software for designing and simulating high-frequency electronic products such as antennas, radar systems, high-speed electronics found in communications systems (e.g. mobile phone), advanced driver assistance systems (ADAS), satellites, IC packages and internet-of-things (IoT) products.
 +
 +
This example can be regarded as an open problem where the radiation boundary condition is used as a boundary condition. For this problem, we solve the vector wave equation. The car body is taken into account as a finite conductivity boundary and the excitation is the incident field from the cable network.
 +
 +
As a result, the electric and the magnetic field intensities are visible on the car body. You can see the effect of the cable harness on these animations.
 +
</blockquote>
  
 
== References ==
 
== References ==
 
{{reflist}}
 
{{reflist}}

Latest revision as of 19:52, 28 January 2020

Cable Harness Analysis

VehicleCables.jpg

CableHarsness.gif

Whole wiring of a vehicle. The magnetic field intensity in the wire and in the car body. [Click to see animation.]

Instructor

  • Dániel Marcsa (lecturer)
  • Lectures: Monday, 14:50 - 16:25 (D201), 16:30 - 17:15 (D105)
  • Office hours: by request

Teaching Assistants:

  • -
  • Office hours: -.

Purpose of the Assignment

The geometry of the problem with the yellow cable harness.
The geometry of the problem with the yellow cable harness.

The student will learn the main steps of the finite element method, such as preparing the model (creating or importing geometry), specifying material parameters, boundary conditions, and excitation through a full-wave problem. This example gives a brief insight into the cable harness analysis through an automotive example.

Knowledge needed to solve the problem

  • The steps of the finite element method;
  • Theoretical knowledge of full-wave fields (for defining materials, excitation);
  • Basic knowledge of electric network theory.

Steps to solve the problem

After launching ANSYS Electronics Desktop, open the file CableHarness_Example.aedt using the File [math] \to [/math] Open menu.
To use ANSYS 2D Extractor, ANSYS HFSS and ANSYS Circuit, the Help menu and YouTube videos provide a lot of help.

Problem Definition and Results

Electric field intensity vectors in the dielectric material in ANSYS 2D Extractor.
Electric field intensity vectors in the dielectric material in ANSYS 2D Extractor [Click to see animation.].
The driving circuit of cable in ANSYS Circuit.
The driving circuit of cable in ANSYS Circuit.

In this case, the whole problem is pre-defined. The reason for this is to avoid lengthy setup and basically, the purpose of the example is to look at the effect of high-frequency cables for the car body. Thanks to this example, students explain why you need to pay attention to the proper cable routing in vehicles. However, we review the structure of this task.

The problem is split into three parts:

  • The analysis of cable (ANSYS 2D Extractor);
  • the set up of cable harness electric circuit (ANSYS Circuit);
  • and the high-frequency analysis of the car body with cable harness (ANSYS HFSS).

Before and during the run, we briefly review the settings of the problem.

It is important to note that in the previous two examples, adaptive meshing used. However, in the case of a time-dependent (transient) problem, it is not possible to use the adaptive mesh, so we need to define the discretization of the problem with different mesh operations.

Analysis of Cable Parasitics (ANSYS 2D Extractor)

ANSYS 2D Extractor efficiently performs the 2D quasi-static electromagnetic field simulations (ANSYS Q3D Extractor for 3D problems) required for the extraction of RLCG parameters (R - resistance, L - inductance, C - capacitance, G - conductance) from an interconnect structure.

As you can see in the figure, the cable has positive, negative and return veins. The veins wrapped by insulation and the outer sheath.

The simulation frequency is 300 MHz and the result of the analysis is shown in the following tables.

Conductance matrix of cable.
Conductance [[math]\mu\text{S}[/math]] Negative Positive
Negative 48.46 -24.23
Positive -24.23 48.46
Capacitance matrix of cable.
Capacitance [[math]\mu\text{F}[/math]] Negative Positive
Negative 117.269 -58.634
Positive -58.634 117.268
Resistance matrix of cable.
Resistance [[math]\Omega[/math]] Negative Positive
Negative 1.912 0.941
Positive 0.941 1.895
Inductance matrix of cable.
Inductance [[math]\mu\text{H}[/math]] Negative Positive
Negative 0.134 0.067
Positive 0.067 0.134

Driving Circuit of Cable Harness (ANSYS Circuit)

The electric field intensity in the wire and in the car body in ANSYS HFSS.
The electric field intensity in the wire and in the car body in ANSYS HFSS. [Click to see animation.]

The return path is grounded, while a port with 50[math]\Omega[/math] terminal impedance is defined for the negative and positive conductor. The parasitic parameters of the cable veins are coming from the 2D Extractor simulation. The results of this circuit simulation are used as the excitation of finite element simulation in HFSS.

The excitation of the two non-grounded wires of the cable is sinusoidal. The amplitude of sine excitation is 0.5V, and the phase difference between negative and positive wires is 180 degree.

Car Body with Cable Harness (ANSYS HFSS)

ANSYS HFSS (High Frequency Structure Simulator) is a 3D electromagnetic simulation software for designing and simulating high-frequency electronic products such as antennas, radar systems, high-speed electronics found in communications systems (e.g. mobile phone), advanced driver assistance systems (ADAS), satellites, IC packages and internet-of-things (IoT) products.

This example can be regarded as an open problem where the radiation boundary condition is used as a boundary condition. For this problem, we solve the vector wave equation. The car body is taken into account as a finite conductivity boundary and the excitation is the incident field from the cable network.

As a result, the electric and the magnetic field intensities are visible on the car body. You can see the effect of the cable harness on these animations.

References

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