1. Chapter 3 ANSYS v9.0 Multiphysics & Electromagnetics

2. ANSYS Workbench Electromagnetics

3. Workbench Electromagnetics
Contents
Workbench Electromagnetics
Workbench Emag Roadmap
Design Modeler
Enclosure Symmetry
Winding Bodies
Winding Tool
Simulation

4. Workbench Emag Roadmap
LF Emag capability will be exposed over several release cycles:
3D Magnetostatics (9.0)
3D Electrostatics (10.0)
3D Current conduction
Circuit elements
Time transient & 2D
Workbench v9.0 is the first release with electromagnetic analysis capability.
Support solid and stranded (wound) conductors
Automated computations of force, torque, inductance, and coil flux linkage.
Easily set up simulations to compute results as a function of current, stroke, or rotor angle.
Workbench Emag capability is mapped to & accessed via:
ANSYS Emag (stand alone or enabled task)
ANSYS Multiphysics license keys.

5. Workbench Emag Markets
Target markets:
Solenoid actuators
Permanent magnet devices
Sensors
Rotating Electric machines
Synchronous machines
DC machines
Permanent magnet machines

6. Workbench Electromagnetics
Contents
Workbench Electromagnetics
Workbench Emag Roadmap
Design Modeler
Enclosure Symmetry
Winding bodies
Winding Tool
Simulation

7. Enclosure Symmetry
Feature: The Enclosure feature now supports symmetry models when the enclosure shape is a box or a cylinder:
Up to 3 three symmetry planes can be specified.
Full or partial models can be included in the Enclosure.
During the model transfer from DesignModeler to Simulation, the enclosure feature with symmetry planes forms two kinds of named selections:
Open Domain
Symmetry Plane
The Enclosure tool is used to enclose the bodies of a model in a material typically required for an Emag analysis.
If a full model is used, symmetry planes will slice the model and discard the unused geometry, then enclose the symmetry model with an enclosure

8. Workbench Electromagnetics
Contents
Workbench Electromagnetics
Workbench Emag Roadmap
Design Modeler
Enclosure Symmetry
Winding bodies
Winding Tool
Simulation

9. Winding Bodies & Tool
Feature: Design Modeler (DM) includes two new tools to allow a user to easily create current carrying coils:
Winding Bodies: Used to represent wound coils for source excitation. The advantage of these bodies is that they are not 3D CAD objects, and hence simplify modeling/meshing of winding structures.
Upon “attach to Simulation”, Winding Bodies are assigned as Conductor bodies.
Winding Tool: Used to create more complex coils for motor windings. The Winding Tool uses a Worksheet table format to drive the creation of multiply connected Winding Bodies. Or a user can read in a text file created by MSExcel.
Benefits: Very easy to use, rapid creation of coil windings.
Winding Bodies: Used to represent wound coils for source excitation. They are defined from line bodies. The advantage of these bodies is that they are not 3D CAD objects, and hence simplify modeling/meshing of winding structures. The winding bodies are easy to use representations of SOURC36 elements.

10. Winding Bodies
Tangent orientation vector (blue arrow) defines direction of current.
Winding cross-section displayed
A line body can be promoted to a winding body. Turns and cross-section (CS) dimensions are entered

11. Winding Tool
Complex coil windings may be created using the Winding Tool:
The Winding Tool inserts a “Winding#” into the model tree.
A “Details” view is used for geometric placement.

12. Winding Tool Each Winding consists a number of related Winding Bodies.
The related Winding Bodies are shown in the Parts/Bodies branch:
Winding Bodies

13. Winding Table File
Each Winding has a Winding Table File associated with it.
The Winding Table File can be created directly in DM
The Winding Table File can be exported to or imported from a text file.
Each row corresponds to a created Winding Body

14. Winding Table File
The Winding Table File can be exported to or imported from a text file.

15. Winding Tool Example Winding 1 highlighted with rotor
Complete DC Motor model

16. Winding Options Coils may have different radii between IN & OUT slots
Multiple coils may be stacked in the same slot

17. Winding Options - Skew
A skew angle may be identified for the coil winding slots
Many motor designs employ a skewed coil form.

18. Winding Slot Clash Detection
Winding Tool automatically detects if the coil clashed with
another part and warns the user

19. Contents Workbench Electromagnetics Design Modeler Simulation
Workbench Emag Roadmap
Design Modeler
Enclosure Symmetry
Winding bodies
Winding Tool
Simulation
Tools Layout
Material Properties
Air Gap Mesh Sizing
Conductors
Solution

20. Simulation Tools Layout
Electromagnetic Toolbar
Simulation Environment:
Emag boundary conditions
Conductor source excitation
Solution Results
Field
Force
Torque
Inductance
Flux linkage

21. Winding Body Transfer in Simulation
Winding bodies are automatically assigned to conductor bodies.
From the Winding Tool, each Phase Winding is assigned as a unique conductor.
In this example, Conductor A consists of 2 winding bodies.

22. Material Property Support
Both linear & nonlinear Emag materials are supported by Engineering Data:
Soft materials (Steel, iron, etc.)
Constant (isotropic)
Laminated (orthotropic)
Linear/nonlinear (single B-H curve)
Hard materials (NdFeB, SmCo, Alnico)
Linear
Nonlinear

23. Materials – BH Curves
BH curves with up to 500 data points are supported

24. Materials - Permanent Magnets
Coordinate systems are used to align the polarization axis of a magnet.
Cartesian and Radial Magnetization are supported.

25. Air Gap Mesh Sizing
Requirement: . In an electromagnetics analysis models typically include narrow gaps between parts such as rotors and stators. It is important to have a refined mesh in these gaps.
Feature: Air Gap Mesh sizing. As for other mesh controls, air gaps are assigned under Advanced Controls in the Mesh Detail.
Benefits: Easy to use mesh refinement, resulting in more accurate analysis results.
Feature: Air Gap Mesh sizing. As for other mesh controls, air gaps are assigned under Advanced Controls in the Mesh Detail.
Face pairs containing the air gap are automatically located.
Gap size face pairs are identified on model for easy verification.
Gap aspect ratio and gap mesh density may be selected per pair.

26. Air Gap Mesh Sizing

27. Conductor Objects
Conductor Objects identify conductors for excitation, inductance, and Post processing. Can be scoped to solid bodies (solid conductors), or Winding Bodies (wound coils)
Excitation: Supports voltage and current loading for solid conductors. Current and phase angle are supported for Winding Bodies.

28. Solution Results

29. Vector & Contour Plots
Vector / Contour is selected in the Solution objects “Definition”

30. Inductance & Flux Linkage
Solution branch can insert Inductance & Flux linkage post processing calculations. Self and mutual inductance is computed.

31. Parameter Sweeps
The Emag analysis can be fully parameterized so that a user can easily extract force or torque versus rotor position etc.
An example will be available to demonstrate this shortly!

32. ANSYS Multiphysics v9.0

33. ANSYS Multiphysics Contents Thermoelectric Direct Coupled Field
LF Electromagnetics
HF Electromagnetics

34. Thermoelectric Analysis
Feature: New thermoelectric analysis option on the series 22X direct coupled-field elements includes:
Seebeck, Peltier, Thomson effects
Transient electrical effects (capacitive “damping”)
Benefit: Addresses new thermoelectric applications where temperature stabilization, temperature cycling, compact or pinpoint cooling are required.
Applicable to: PLANE223, SOLID226, SOLID227. Steady-state & transient analysis.
The existing (pre- ANSYS 9.0) thermoelectric analysis can be used to determine the temperature distribution in a conducting material due to Joule heating effects – the heating of a conductor resulting from the flow of direct (DC) electric current. Joule heating is proportional to j2, where j – is the electric current density, is independent of the current direction, and is irreversible. Joule heat coupling, supported by the elements LINK68, PLANE67, SOLID69, 5, 98, SHELL157, has been successfully applied to model the heating of electromagnetic devices where it plays a major role.
At ANSYS 9.0, the thermoelectric analysis has been enhanced to include Seebeck, Peltier, and Thomson effects. These three effects are the ways the coupling between the thermal and electric currents manifests itself, and are closely related.
Seebeck effect – The temperature gradient produces an electric potential (Seebeck voltage). The voltage produced is proportional to the temperature gradient, and the proportionality coefficient is known as Seebeck coefficient (). Typical application: thermoelectric thermometry (thermocouples), thermoelectric generators.
Peltier effect – The passage of the electric current through the junction of two different thermoelectric materials produces heating or cooling of the junction. Whether the junction is heated or cooled depends on the direction of the current, i.e. the heat absorbed or released at the junction is proportional to j. The proportionality constant is known as the Peltier coefficient (), and is related to Seebeck coefficient as =T, where T is the absolute temperature. Typical application: thermoelectric coolers.
Seebeck and Peltier effects are the basis for using thermoelectric materials for the direct conversion between thermal and electric energies.
Thomson effect – Heat is absorbed or released when electric current flows in a nonuniformly heated material ( is temperature dependent), i.e. the amount of heat absorbed/generated is different from that absorbed/generated at constant temperature. The heat is proportional to both the electric current and temperature gradient.
In addition to these new thermoelectric effects, the transient thermoelectric analysis now accounts for the transient electrical effects.

35. Thermoelectric Elements
Name
PLANE223
SOLID226
SOLID227
2-D 8-node
3-D 20-node
3-D 10-node
Coupled-field solid
Geometry
Product
MP,PP,ED
KEYOPT(1)
110 (thermoelectric analysis)
DOFs-Reactions
Temperature (TEMP) – Heat flow (HEAT)
Electric scalar potential (VOLT) - Electric current (AMPS)
Material Properties
KXX, KYY, RSVX, RSVY, SBKX, SBKY, DENS, C, ENTH, PERX, PERY
KZZ, RSVZ, SBKZ, PERZ
Loads
SF: CONV, HFLUX, RDSF
BF: HGEN
KEYOPT(3)
0 - Plane
1-Axisymmetric

36. Thermocouple example
Differential junction temperature results in a 42 mV potential difference
Material B
TC= 0 ºC
TR= 25 ºC
Voltage distribution
TH= 100 ºC
This example problem illustrates the Seebeck effect.
The thermocouple circuit consists of two dissimilar materials (A and B), connected as shown in the <Left figure>. In this example, the measured temperature is the temperature of the hot junction Th=100 ºC, while the junction maintained at a cool temperature Tc=0 ºC is used as a “reference”. Both terminals are at room temperature TR= 25 ºC . With the heat applied to the hot junction, a voltage will appear across the terminals. The output voltage <Right figure>, known as the Seebeck emf (electromotive force), can be expressed as VS=|A-B |(TH-TC), where A and B are the Seebeck coefficients of material A and B respectively.
VS= V
Material B
Material A

37. Peltier Cooler Example
10A current flow results in a 57oC temperature differential.
conductor
Iin= 10 A
Temperature distribution:
Cold side T= -3 oC
n-type material
(= -195Volt/ oC)
The thermoelectric analysis enhanced with Seebeck, Peltier, and Thomson effects can be used to simulate a thermoelectric cooler, sometimes called a thermoelectric module or Peltier cooler. A Peltier cooler is a semiconductor-based electronic component that functions as a small heat pump. The simplest cooler (thermoelectric couple) consists of a p-type (positive charge carriers - holes) and n-type (negative charge carriers – electrons) branch to which are attached metallic conductors <Left figure>. By applying a DC electric current to the thermoelectric couple, heat will be moved through the couple from one side to the other.
In the present simulation, the hot side is maintained at +54 ºC, while an electric current of 10 Amperes is applied to the n-material. As a result, the opposite (cold) side is cooled to –3 ºC <Right figure>.
It is important to note that since the Peltier heat is transported by electric current, the effect will be reversed if the current flows into an opposite direction: the upper face of the couple will become hot. Consequently, a thermoelectric module may be used for both heating and cooling thereby making it highly suitable for precise temperature control applications.
Iout
p-type material
(=230Volt/ oC)
Hot side T= 54 oC

38. Markets and Applications
Example markets and applications for the thermoelectric analysis capability:
Electronic and optical component cooling
CPU, photo-detectors, low noise amplifiers, laser diodes, fiber optics
Consumer products
Portable food/beverage coolers, automotive seat cooling/heating
Medical, laboratory and scientific equipment
Blood analyzers, thermal cycling devices (blood, lymph, DNA), portable insulin coolers, heart and eye surgery, hypothermia blankets
Military & Space
Night vision equipment, guidance systems, pilot suit temperature regulation
Indoor environmental devices
Conditioners, fans, humidifiers
Thermoelectric coolers are ideally suited for a wide variety of applications due to their small size, high reliability, wide operating temperature range, low power requirements, and the absence of refrigerant liquids or gases. They can provide pinpoint cooling for heat sensitive electronic components (infrared detectors, computer chips, low noise amplifiers). Compact cooling units are also used to stabilize the operating temperature of laser diodes, fiber optical networks, charge-coupled device (CCD) detectors in digital cameras. Thermoelectric components can also be found in many consumer products (e.g. portable food and beverage coolers), medical and laboratory equipment (e.g. blood analyzers, portable insulin coolers), and military equipment (night vision devices).

39. ANSYS Multiphysics Contents Direct Coupled Field LF Electromagnetics
Electromagnetic forces & torque
Conductance Matrix
HF Electromagnetics

40. Electromagnetic Force & Torque
Feature: New command and underlying numerical (Virtual Work force) calculation to summarize electromagnetic force and torque.
Command: EMFT
Benefit: Easier to use, faster, & more accurate.
Electric and magnetic methodology are now the same – consistency.
Applicable to: SOLID117, PLANE121, SOLID122, SOLID123.
Unlike FMAGSUM, which requires you to specify element components first and then flag them using FMAGBC, EMFT requires only that you select the nodes of interest and issue the EMFT command in POST1
Electric and magnetic methodology are now the same – consistency
Forces are stored as items:
_FXSUM, _FYSUM, _FZSUM, and _FSSUM.
Torque is stored as items:
_TXSUM, _TYSUM, _TZSUM, and _TSSUM.

41. Electromagnetic Forces – 2D
Electrostatic Forces, 2D MEMS comb drive example
Potential distribution
Electrostatic forces

42. Electromagnetic Forces – 2D
MEMS comb drive example results:
Electrostatic Force (N)
Driving (x)
Transverse (y)
Simplified analytical [1,2]
(Ignores fringing effects)
5.3110-9
0.0
ANSYS (Maxwell Stress Tensor)
3.5510-9
0.00610-9
ANSYS (New Virtual Work)
5.6510-9
0.00510-9
REFERENCES
1. T.-C. H. Nguyen W.C. Tang and R.T. Howe. Laterally driven polysilicon resonant microstructures. Sensors and Actuators A, 20:25–32, 1989.
2. M.W. Judy W.C. Tang, T.-C.H. Nguyen and R.T. Howe. Electrostatic-comb drive of lateral polysilicon resonators. Sensors and Actuators A, 21-23:328–331, 1990.

43. Electromagnetic Forces- 3D
Concentric sphere verification benchmark:
Half symmetry problem description
Electrostatic forces
1/8th symmetry Potential distribution

44. Electromagnetic Forces- 3D
Concentric sphere results:
Radial Electrostatic Force (N)
Fa (inner)
Fb (outer)
Analytical model
2.2310-6
-0.5610-6
ANSYS (Maxwell Stress Tensor)
1.5910-6
-0.7910-6
ANSYS (New Virtual Work)
2.2110-6
-0.5510-6
REFERENCES

45. Electromagnetic forces – 3D
TEAM20 Solenoid Benchmark Results:
Vertical (z-direction) force (N)
1000 A-turns
3000 A-turns
5000 A-turns
Experimental (target)
8.10
54.4
80.1
ANSYS (Old Virtual Work)
7.24
51.3
76.7
ANSYS (New Virtual Work)
7.25
51.4
76.8
REFERENCES
1. M. Gyimesi, D. F. Ostergaard, “Analysis of Benchmark Problem TEAM20 with Various Formulations”, Proceedings of TEAM Workshop, COMPUMAG, Rio, 1997.
2. M. Gyimesi, D. F. Ostergaard, “Mixed Shape Non-Conforming Edge Elements”, IEEE Transactions on Magnetics, Vol. 35 No. 3, 1999, pp
3. M. Gyimesi, D. F. Ostergaard, “Non-Conforming Hexahedral Edge Elements for Magnetic Analysis”, IEEE Transactions on Magnetics, Vol 34 No. 5, 1998, pp
See also new Verification Example: VM241.

46. Conductance Matrix
Feature: A new macro is now available to extract conductance from multi-conductor systems. This macro, which is used much like the CMATRIX macro for capacitance, allows you to extract self and mutual conductance terms so that equivalent circuit lumped conductors can be defined for use in circuit simulators.
Command: GMATRIX
Benefit: Provides improved lumped parameter connectivity with circuit simulators. Combined with CMATRIX, and LMATRIX, a user can now extract L, C & G matrices for subsequent use circuit simulators.
Applicable to:
SOLID5,PLANE67,LINK68,SOLID69,SOLID98
PLANE230,SOLID231,SOLID232
Not available with Trefftz method.

47. Contents ANSYS Multiphysics Direct Coupled Field LF Electromagnetics
HF Electromagnetics
Frequency Selective Surfaces
Lumped Circuits
Fast Frequency Sweep VT
SPICE sub-circuit extraction (Beta)
Smith Charts
Specific Absorption Rate (SAR)
Multi-port Power Calculation

48. Frequency Selective Surfaces
Features:
To compliment the Floquet periodic boundary condition (released at 8.1), a plane wave source port (via HFPORT) is now available to launch a plane wave for a scattering analysis of a periodic structure. Such a structure is commonly referred to as a Frequency Selective Surface (FSS).
Radar Cross Section (RCS) results can be displayed and listed for 2D TE and TM incident plane waves (via PLHFFAR and PRHFFAR).
FSS Reflection and transmission properties are calculated using the new FSSPARM macro.
Benefit: A new capability introduced to address a growing market need to analyze FSS.
Applicable to: HF119, HF120.(Hex, Tet, Wedge and Pyramid) & PML.
Commands: HFPORT, PLHFFAR, PRHFFAR, FSSPARM
Incident Plane Wave
Periodic Structure

49. Frequency Selective Surfaces
FSS example: Plane wave incident at 45o z
45
E-Field (x) Contours y x
90
Far field pattern

50. Lumped HF Circuit Elements
Feature: HF Lumped “RLC” circuit elements. They are applied to the mid-nodes of element edges using the BF command.
Benefit: A new capability that can be used to greatly simplify a HF analysis in a similar manner to our LF Emag circuit elements. The lumped circuit greatly reduces the number of DOF’s.
Application: Use to simulate passive devices like resistors, or to simplify a structure when fringe effects at discontinuities can be ignored.
Applicable to: HF119, HF120 (Hex, Tet, Wedge and Pyramid).
Lumped RLC circuit model
Microstrip line
FEA Domain (Mesh)

51. Lumped HF Circuit Elements
Command: BF, <Node>, Lump, <value1>
Six types of lumped circuits are available, value1 of the BF command is used to specify which :
Complex impedance
Shunt RCL circuit
Series RL with shunt C
Series RCL
Series RC with shunt L
Series LC with shunt R

52. SPICE Sub-circuit Extraction
Feature: SPICE Compatible Sub-circuit Extraction. Feature synthesizes an RLCG equivalent circuit for passive multi-port electromagnetic structure.
Commands: SPICE
Benefit: Ability to easily connect ANSYS to system level EDA circuit simulation tools for signal integrity applications. Allows ANSYS to start to address high frequency time domain analysis. Extracted circuit is SPICE compatible.
Usage: SPICE sub circuit is extracted from S-parameter frequency sweep.
Applicable to: HF119, HF120.(Hex, Tet, Wedge and Pyramid). S parameter extraction only.
9.0 BETA

53. SPICE Sub-circuit Extraction
Integrating ANSYS HF Emag into Signal Integrity Process Flow:
ANSYS Multiphysics
3rd Party EDA Signal Integrity tool suite
Parametric Geometry
Creation
Design Rules
HF Emag solver
S-parameter sweep
Time Transient Waveforms
SPICE circuit extraction
SPICE simulation
9.0 BETA

54. Fast Frequency Sweep VT
Feature: The fast Frequency Sweep VT module has been enhanced using a perfect absorber. This provides a 20% faster solution than the original VT method.
Commands: SPSWP, HROPT
Benefit: Fast S-parameter calculations over a wide frequency range.
Usage: Frequency Sweep VT is an additional charge module that can be added to ANSYS Multiphysics.
Applicable to: HF119, HF120.(Hex, Tet, Wedge and Pyramid) S parameter extraction only.

55. Smith Chart & Network Parameters
Features:
Conversion of scattering (S), admittance (Y) or impedance (Z) parameters for display on a Smith Chart.
Display the required network parameters and generate a new Touchstone file for the required parameter.  
Plot the required network parameters as the response of the frequency on an x-y graph.
Commands: PLSCH, PLSYZ, PRSYZ
Benefit: Ability to display results in formats that are widely accepted in the industry. Easier for RF engineers to understand ANSYS results!
Applicable to: HF119, HF120.(Hex, Tet, Wedge and Pyramid).

56. Smith Chart & Network Parameters

57. Specific Absorption Rate (SAR)
Features: Specific Absorption Rate (SAR) Calculation for lossy materials. Can plot or list SAR distribution using ETABLE of ANSYS postprocessor.
Commands: SAR is calculated when a mass density of the material is defined by the MP command. Results are stored in the HF119 and HF120 Item and Sequence Numbers Table.
Benefit: Ability to compute SAR is an important capability required for primarily biomedical studies of effects of HF energy on living tissue.
Applicable to: HF119, HF120.(Hex, Tet, Wedge and Pyramid).

58. Multi-Port Power Calculation
Feature: Power Calculation for Multi-port High-Frequency networks. Feature provides:
Input/Output power at ports
Dissipated power in multi-port system
Power reflection/transmission coefficient
Return loss and insertion loss at ports
Command: HFPOWER
Benefit: Ability to compute SAR is an important capability required for primarily biomedical studies of effects of HF energy on living tissue.
Applicable to: HF119, HF120.(Hex, Tet, Wedge and Pyramid).