Computer-Aided Design of Electrical Machine

• Introduction to computer aided design.
• Analysis and synthesis methods -hybrid techniques.
• Introduction
to Finite element method
-
historical
background,
applications, advantages.
• Study of new computer aided machine software using Finite Element
Case study:
• Complete design of an ac machine

1. Computer-Aided Design of Electrical
Machine

2. Computer-Aided Design
•Introduction to computer aided design.
•Analysis and synthesis methods -hybrid techniques.
•IntroductiontoFiniteelementmethod-historicalbackground,
applications, advantages.
•StudyofnewcomputeraidedmachinesoftwareusingFiniteElement
Case study:
•Complete design of an ac machine –steps.(Assignment only)

3. Computer-Aided Design
•Inanypracticaldesignthenumberofvariablesissohighthathand
calculations are impossible.
•Thenumberofconstraintsisalsolargeandforthesetobesatisfiedby
final design, a lengthy iterative approach is required.
•Thisisonlypossiblewiththehelpofcomputerprograms(refer
Flowchart I. J).

4. Computer-Aided Design

5. Computer-Aided Design
A
A
B
B

6. Computer-Aided Design
❖ Explanation of Details of Flowchart
1.Input Data to be Fed into the Program
2. Applicable Constraints I Maximum or Minimum Permissible Limits
3.Output Data to be Printed after Execution of Program
4.VariousObjectiveParametersforOptimizationinanElectricalMachine
•Input Data to be Fed into the Program
•a) Data
•b ) Applicable curves in array format
• c) Applicable tables in array format like

7. Computer-Aided Design
• Explanation of Details of Flowchart
•Input Data to be Fed into the Program
a. Data
1.Rating of the machine (KW/KVA)
2.Rated Voltage
3.Rated Frequency (for AC only)
4.Rated Speed (RPM)
5.TypeofConnectionofPhases
(Star/Delta) for 3 ph AC only
6.Type of Winding (Lap/Wave)
7.Number of Parallel Paths
8. Shunt/Compound in case of DC Machine
9.SquirrelCage/SlipRingtypefor3-phInd.
Motor
10. Rated Slip /Rotor speed for Ind.Motor
I1.SalientPole/Roundrotortypefor3-ph
Alternators
12.Ratedpowerfactorfor3-phAlternators
13. Core/Shell type for Transformers
14 . Ratings of HV /L V for Transformers

8. Computer-Aided Design
•(b) Applicable curves in array format like,
•B/H for magnetic materials used for Core, Poles,
• 2. Loss Cuves for magnetic materials
• 3. Hysteresis loss vs. frequency
•4. Carters coefficients for slots and vent ducts
•5. Apparent Flux density
•6. Leakage Coefficien~ of slots
•7. HP ys. output coefficient for I-ph Ind.Motor

9. Computer-Aided Design
• Applicable tables in array format like,
•I. Output vs. Specific Electric Loading(q)
•2. Output vs. Specific Magnetic Loading(Bav)
•3. Output vs. AT/pole
•4. No. of poles vs. Pole pitch
•5. Depth of Shunt field winding vs. Arm Dia
•6. Standard sizes of brushes
• 7. Powef·-Factor and Efficiency at different ratings of Ind. Motor
•8. Frequency vs. Frequency constant of I-phlnd. Motor
•9. No. of poles vs. DiiDe ratio for I-ph Ind. Motor
•10. Efficiency and PF vs. output for I-ph In9._ Motor
•II. Thickness of Stator winding ins vs. Voltage for Rotating machines
•12. Window space Factor vs. K V A for transformers.
•1

10. Computer-Aided Design
•Computer aided design – Three approaches
•Analysis method
•Synthesis Method
•Hybrid Method

11. Computer-Aided Design
•Analysis method
•Choiceofdimension,typeofmaterialandtypeofconstructionare
madebythedesignerandthesearepresentedtothecomputerasthe
input data
•Theperformanceiscalculatedbythecomputerandisreturntothe
designer to analysis
•Thedesigneranalyzetheperformanceandmakeanotherchoiceof
input if necessary and the performance is recalculated
•Thisprocedureisrepeatedtilltheperformancerequirementsare
satisfied

12. Computer-Aided Design
•Analysis method

13. Computer-Aided Design
•Analysis method – Advantages
•It is fairly easy to program to use and to understand
•Time saving
•Simple programs
•The results are highly acceptable by the designers

14. Computer-Aided Design
•Synthesis Method

15. Computer-Aided Design
B
B
A
A

16. Computer-Aided Design
•Synthesis Method
•The desired performance is given as the input to the computer
•Thelogicaldecisionsrequiredtomodifythevaluesofvariablestoarrive
atthedesiredperformanceareincorporatedintheprogramasasetof
instructions
•Advantages
•Saving in time
•Dis – advantages
•Complex program
•Calculation cost is high

17. Computer-Aided Design
•Hybrid Method
•Thismethodincludebothanalysisaswellassynthesismethodinthe
program

18. Introduction to Finite Element Analysis
• Introduction to Finite Element Analysis
•TheFiniteElementMethod(FEM)isanumericaltechniquetofindapproximate
solutions of partial differential equations.
•Itwasoriginatedfromtheneedofsolvingcomplexelasticityandstructuralanalysis
problems in Civil, Mechanical and Aerospace engineering.
•FEMallowsfordetailedvisualizationandindicatesthedistributionofstressesand
strains inside the body of a structure.
•ManyofFEsoftwarearepowerfulyetcomplextoolmeantforprofessionalengineers
with the training and education necessary to properly interpret the results.
•SeveralmodernFEMpackagesincludespecificcomponentssuchasfluid,thermal,
electromagnetic and structural working environments.
•
•

19. Introduction to Finite Element Analysis
• Introduction to Finite Element Analysis
•FEMallowsentiredesignstobeconstructed,refinedandoptimizedbefore
the design is manufactured.
•Thispowerfuldesigntoolhassignificantlyimprovedboththestandardof
engineeringdesignsandthemethodologyofthedesignprocessinmany
industrial applications.
•TheuseofFEMhassignificantlydecreasedthetimetotakeproductsfrom
concept to the production line.
•Onemusttaketheadvantageoftheadventoffastergenerationofpersonal
computersfortheanalysisanddesignofengineeringproductwithprecision
level of accuracy.
•

20. Introduction to Finite Element Analysis
• Background of Finite Element Analysis
•ThefiniteelementanalysiscanbetracedbacktotheworkbyAlexanderHrennikoff
(1941)and Richard Courant(1942).
•Hrenikoffintroducedtheframeworkmethod,inwhichaplaneelasticmediumwas
represented as collections of bars and beams.
•Thesepioneersshareoneessentialcharacteristic:meshdiscretizationofa
continuousdomainintoasetofdiscretesub-domains,usuallycalledelements.•In
1950s,solutionoflargenumberofsimultaneousequationsbecamepossiblebecause
ofthedigitalcomputer.•In1960,RayW.Cloughfirstpublishedapaperusingterm
“FiniteElementMethod”.•In1965,Firstconferenceon“finiteelements”washeld.
•In1967,thefirstbookonthe“FiniteElementMethod”waspublishedby
ZienkiewiczandChung.•Inthelate1960sandearly1970s,theFEMwasappliedtoa
wide variety of engineering problems.

21. Computer-Aided Design

22. Computer-Aided Design

23. Computer-Aided Design