1 / 60

OPERA 14 - Review of New and Updated Features

OPERA 14 - Review of New and Updated Features. Overview. Changes to the Opera Manager Changes in 2D Changes in 3D Future work. Opera 14 Manager ‘look’. Optimiser: new functionality. Multiple optimisation runs Now available through the Opera Manager Initial designs

lummus
Download Presentation

OPERA 14 - Review of New and Updated Features

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. OPERA 14 - Review of New and Updated Features

  2. Overview • Changes to the Opera Manager • Changes in 2D • Changes in 3D • Future work Document Title

  3. Opera 14 Manager ‘look’ COMMERCIAL IN CONFIDENCE

  4. Optimiser: new functionality • Multiple optimisation runs • Now available through the Opera Manager • Initial designs • The number of initial designs can now be set (previously a multiple of the design variable number). The set of designs can be spread across the design space (Hammersley Sequence) or can be arranged on an n-dimensional grid (parameter sweep). • Experimental designs • The number of concurrent designs can now be set by the user to exploit systems with multiple processors. • Stopping Criteria • The minimum probability of improvement has been replaced by number of iterations with no improvement. COMMERCIAL IN CONFIDENCE

  5. Opera 14 Manager & Licensing • Improvements to batch queue handling using a single database to store queue of job & their status • Separate LMX license utility for Network server installations COMMERCIAL IN CONFIDENCE

  6. Opera-2d model definition • Improvements to Opera-2d/PP • Replications with different conductor numbers • Overlaying regions COMMERCIAL IN CONFIDENCE

  7. Opera-2d model definition • Can now overlay (but not overlap) regions COMMERCIAL IN CONFIDENCE

  8. Region splitting • Can split a region across two corners COMMERCIAL IN CONFIDENCE

  9. Automatic Gap & Layers definition within the new Background command COMMERCIAL IN CONFIDENCE

  10. Opera-2d Circuits restrictions lifted • In Opera-2d allow eddy current loops, with conductors included, that do not contain external resistance • When defining shared components (R or L) in external circuits, opposite current directions in the two circuits are accommodated - indicated by negative shared circuit numbers. • Circuit editor will share R and L components between more than 2 loops • Non-linear components, such as diodes, can be included in external circuits. The Circuit Editor sets up expressions for functional resistance dependent on current to model such components: • Piecewise linear • Exponential COMMERCIAL IN CONFIDENCE

  11. Circuit Editor • Initially developed as a stand-alone utility • Exports command scripts • for Opera-2d and Opera-3d circuit definition • Save and Load VFC files • Intuitive, interactive interface • but no command line! • Integration into Opera completed in V14 • Define circuits • Using circuit editor is the default • Using old dialogs and commands if required • Cannot convert old circuit data to a circuit layout • New CircuitEditor command allows some command line control, e.g. • Load a new vfc file • Modify parameters of circuit components • Integrates into the model directly, e.g. • Identifies conductor numbers or circuit windings COMMERCIAL IN CONFIDENCE

  12. Circuit Editor • What you would expect from a circuit layout tool • Interactive interface (only some command line control!) • Draw wires and position components • Drag-and-drop components • Move groups of components • Maintaining wire connections • Cut / Copy / Paste components • Undo / Redo • Save / Load COMMERCIAL IN COFIDENCE

  13. Circuit Editor • Components • Functional Power Supplies incl. 3-phase supplies • Functional Resistors • Inductors and Capacitors • Switches • Diodes • File management • VFC files hold circuit layout • Command file that generates circuit layout can be stored COMMERCIAL IN COFIDENCE

  14. Circuit Editor Interaction • Double clicking used to start a new wire. If over an existing wire, the new wire will start at the position clicked COMMERCIAL IN COFIDENCE

  15. Adding Components • Useful warnings provided during circuit construction • Position cursor over a component or component type in the left hand list view. Press and hold the left mouse button and drag the component into the diagram. COMMERCIAL IN COFIDENCE

  16. OPERA-2d Winding • OPERA-2d model conductor numbers making up the circuit are entered, along with the number of turns, symmetry factor etc. COMMERCIAL IN COFIDENCE

  17. OPERA-3d winding • OPERA-3d model conductor names making up the circuit are entered, along with the number of turns, symmetry factor etc. COMMERCIAL IN COFIDENCE

  18. Switches • Logical operators used to describe switching • Internally OPERA creates logical expression COMMERCIAL IN COFIDENCE

  19. Diodes • Piece-wise linear and exponential models available COMMERCIAL IN COFIDENCE

  20. Example 1: A pure circuit problem A star supply connected across an unbalanced delta load COMMERCIAL IN COFIDENCE

  21. Listing Results COMMERCIAL IN COFIDENCE

  22. Example 2: Driving a Solenoid valve • Valve operated cyclically with 1 coil excited at any time COMMERCIAL IN COFIDENCE

  23. Example 3: A Brushless PM Motor Drive • 3-phase BLPM converter circuit with trapezoidal excitation pattern COMMERCIAL IN COFIDENCE

  24. Other developments • Fast solvers • Opera-2d • Option to use a Direct Sparse Solver with Opera-14 solvers. Expect • Significant increase in speed simply by moving to the direct solver (tests have shown speed ups in the range of 3-13 times) • … at the expense of more memory usage • This technology can exploit multiple processors. Additional increase in speed by solving on dual or quad core processors will be researched over the coming months COMMERCIAL IN CONFIDENCE

  25. Direct Sparse Solver in Opera-2d • Static Solver (2d/ST) • A large model (368k elements, 736k nodes) • Solves 12 times faster (1:32 instead of 19:41 on Core i7) • Steady State Solver (2d/AC) • A standard size model (73k nodes, 145k elements) • Solves 2 times faster (0:45 instead of 1:36 on Core i7) COMMERCIAL IN CONFIDENCE

  26. Opera-3d Mosaic Mesh • Developed within the IMPDAHMA project • Allows a mixture of • Hexahedral elements • Prism elements • Pyramid elements • tetrahedral elements • Hexahedral and prism elements • Mapped mesh structure • Allows well shaped elements to be positioned when needed • Allows layers of elements to be defined to match expected field patterns • Allows anisotropic mesh elements to match material characteristics • Restricted to certain volumes by topological constraints COMMERCIAL IN CONFIDENCE

  27. Opera-3d Mosaic Mesh • Hex elements • Allowed in 6 sided region, 12 edge, 8 node region (cuboid) • But with any curvature on edges and faces • E.g. elliptic, conic tube (split into 2 cells) Mesh layering on any face to allow fine control of mesh away from a surface. Mesh layering does not affect geometry of model body. COMMERCIAL IN CONFIDENCE

  28. Opera-3d Mosaic Mesh COMMERCIAL IN CONFIDENCE

  29. Opera-3d Prisms and Pyramids COMMERCIAL IN CONFIDENCE

  30. Opera-3d Mosaic Mesh • All solvers are adapted to use the combination of different element shapes • Typically hex element meshes produce fewer equations • Faster solution times • For anisotropic field patterns, can produce better results Geometry layered tetrahedra Mesh layered hexahedra COMMERCIAL IN CONFIDENCE

  31. Surface Impedance Model • Thin skin depth eddy currents are difficult to model • Change calculation in Elektra-SS • Simple switch to exclude eddy current volumes as skin depth decreases • Automatically include impedance boundary condition at the interface • Implementation uses analytic fields for infinite conducting plate • Assumes linear (in mu and sigma) material • Validity • Requires small skin depth relative to model dimensions • Typically 1% accuracy • Breaks down at corners • Effects are small if skin depth is small COMMERCIAL IN CONFIDENCE

  32. Assignment of SI model • Assign ‘SI model’ to a material (volume) COMMERCIAL IN CONFIDENCE

  33. Surface Impedance Model • Test results • Against analytic formula for prolate spheroid in a AC uniform field • Sample test problem of an NDT crack model • Relatively large skin depth (plate 10mm, skin depth 3mm) COMMERCIAL IN CONFIDENCE

  34. Elektra-SS Surface ImpedanceAnalytic comparison COMMERCIAL IN CONFIDENCE

  35. Elektra-SS Surface ImpedanceNDT example Using volume mesh Equations:458453Iterations: 164 Using Surface Imp.Equations: 325450Iterations: 220 Real benefit as frequency increases so modelling becomes impractical. For f*10 : it = 189 For f*100: it = 155 COMMERCIAL IN CONFIDENCE

  36. Elektra-SS Surface ImpedanceNDT Example Plot of induced current on interface surface COMMERCIAL IN CONFIDENCE

  37. Surface Impedance Modelling • Simple Example • Copper tube • Exciting solenoid • AC analysis • .5kHz, 5kHz, 50kHz • Small defect affects eddy currents • ¼ symmetry • Use SIBC • Use different meshes COMMERCIAL IN CONFIDENCE

  38. Surface Impedance Modelling • Two tetrahedral meshes • Crude • Fine • Activate SIBC • Option in material property • Comments • At low frequency • Some fields should transmit through • SIBC will block this • At high frequency • Volume mesh does not capture effects in the skin depth COMMERCIAL IN CONFIDENCE

  39. Surface Impedance ModellingWith Mosaic mesh • Use mosaic meshing with the coarse mesh • Cut cylinder into 2 cells • Set preferred elementshape in cells to be ‘Hex or Prism’ • Set mesh layering on inner faces of cylinder COMMERCIAL IN CONFIDENCE

  40. Surface Impedance ModellingResults COMMERCIAL IN CONFIDENCE

  41. Surface Impedance ModellingSummary • Use SIBC to allow calculation of highly conducting materials • Removes the need to resolve the skin depth • Simple switch to activate in required materials • Allows modelling of extremes which would be otherwise impossible • Generally a slightly faster solution when activated, mainly due to reduced equation count • Don’t use if transmission of fields through the conductor is important • Check the skin depth • Post-processing available: • power, energy, forces and integral fields • Surface fields for display • Some artifacts when displaying surfaces in symmetry planes or accessing fields inside the conductors COMMERCIAL IN CONFIDENCE

  42. Force calculation using Virtual Work • The accurate calculation of forces and torques from discrete models of electromagnetic devices is challenging. Why? • The total force or torque on a rigid body is often much smaller than the internal forces that act on the body as a result of the electromagnetic fields • This increases the errors in the calculated total force and torque • The solution errors in a discrete model are highest where the fields are changing rapidly and typically high force densities exist in these areas • Again exacerbating the errors in the total force if there is any cancellation COMMERCIAL IN CONFIDENCE

  43. Methods for the calculation of Forces and Torques • Direct integration of the body forces • Maxwell Stress Integration over a closed surface surrounding a body • Virtual Work • ‘Constant flux’ virtual displacement performed by differentiating the stored energy with respect to a displacement/rotation of a rigid body, keeping the solution fixed. • Here, the only energy change occurs in the layer of elements surrounding the body COMMERCIAL IN CONFIDENCE

  44. Force calculation using Virtual Work • All the methods suffer from the same problems • Large errors near sharp corners where the field is changing rapidly • Cancellation enhances the error in the total force and torque • Optimal approach : use the method that takes best advantage of the solution properties (FEA methods look at stored energy minimisation and hence operating on energy changes, a global quantity, has the best chance of success) • This is Virtual Work or Maxwell Stress integrated on the optimal path(An exact equivalence exists between the two methods providing that the correct path is selected for the Maxwell Stress integration – This is the surface formed by mid-edge points) COMMERCIAL IN CONFIDENCE

  45. Methods .. continued • Virtual work is not a panacea (but it is optimal for the discrete solution) • Maxwell Stress is only exactly equivalent to Virtual work if the right integration path and shape function derivative fields are used (This is what Opera-2d RM and LM do) • With Virtual Work and Maxwell Stress the results are path dependent • Any free space path surrounding a rigid body can be used for the calculation - The results will change with the path chosen-Opera-2d RM averages two paths on either side of the air gap centre-Prior to V14, Carmen averaged the result on two surfaces, but did not use the optimal surface COMMERCIAL IN CONFIDENCE

  46. Comparison of resultsAnalytic test – magnetised bar • An infinitely long bar, uniformly magnetised orthogonal to its axis, rotated about its axis in a uniform external field that is also orthogonal to the bar axis • 2D slice through this system was modelled using Carmen in Opera-3d COMMERCIAL IN CONFIDENCE

  47. Analytic Test - Magnetised Bar %error in Carmen calculated torque ------------Maxwell Stress ------------Virtual work Analytic torque Model Description : 25,000 Tet elements (& edges) in a thin 2D slice Note : Far field boundary truncated at 10 times the bar radius COMMERCIAL IN CONFIDENCE

  48. Integral fields • Notes on Opera Maxwell Stress & Field options • Opera can use source integration from calculated M and J to recover the field • The source integration is optimal for the solution properties • But in situations with high cancellation the numerical integration of the forces calculated from integral source fields is subject to errors (and is expensive) COMMERCIAL IN CONFIDENCE

  49. More on Integral Fields & Cogging Torque • 16 poles (22.5 degree period) • 21 slots • LCM=336 (21 variations in 1 period) Typical Tangential Force Profile COMMERCIAL IN CONFIDENCE

  50. Maxwell Stress combined with Integral Field calculations provide best (not perfect) results COMMERCIAL IN CONFIDENCE

More Related