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Overview of Circuit Simulation Programs

Overview of Circuit Simulation Programs. ECE 546 DIGITAL COMPUTATIONAL TECHNIQUES FOR ELECTRONIC CIRCUITS January 8, 2008 Oleg Wasynczuk. Need for System-of-Subsystems Approach.

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Overview of Circuit Simulation Programs

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  1. Overview of Circuit Simulation Programs ECE 546 DIGITAL COMPUTATIONAL TECHNIQUES FOR ELECTRONIC CIRCUITS January 8, 2008 Oleg Wasynczuk

  2. Need for System-of-Subsystems Approach • Complex engineered systems such as aircraft, modern automobiles, or the terrestrial electric power grid involve a broad spectrum of technologies and interactive subsystems that must work synergistically in order to operate properly • Inter-dependencies between subsystems are becoming more and more prominent

  3. More-Electric Aircraft Power System

  4. Modeling Approaches

  5. + - Synchronous Machine Subsystem Models Distributed Parameter Coupled Circuit Steady State

  6. Power Electronic Subsystem Models Detailed Average Value

  7. Simulation Approaches • Circuit-Based Approaches (Spice, EMTP, Saber, PSIM, Simplorer) • System-Based Approaches (Simulink, ACSL, Dymola) • Block-diagram and/or differential equation oriented • Extensive set of tool boxes including • ASMG (Simulink, ACSL) • Power System Blockset (Simulink) • … • Finite-Element-Based Approaches (Ansys, Maxwell, …)

  8. Circuit-Based Approaches

  9. Circuit-Based Approaches Example Subsystem (Motor Controller)

  10. Circuit-Based Approaches

  11. Circuit-Based Approaches Resistor-Companion Circuit

  12. Circuit-Based Approaches Update Formula O(n3) computational complexity where n = number of non-datum nodes

  13. Simulation Approaches • Circuit-Based Approaches (Spice, Saber, PSIM, Simplorer) • System-Based Approaches (Simulink, ACSL, Dymola) • Block-diagram and/or differential equation oriented • Extensive set of tool boxes including • ASMG (Simlink, ACSL) • Power System Blockset (Simulink) • … • Finite-Element-Based Approaches (Ansys, Maxwell, …)

  14. System-Based Approaches Hierarchical system definition

  15. System-Based Approaches Common Simulink Component Models

  16. System-Based Approaches

  17. Explicit if System-Based Approaches When user starts model, Simulink applies selected integration algorithm to approximate solution at discrete but not necessarily uniform instants of time General Multi-step Formula Implicit algorithms require solution of nonlinear equation (dimension = number of states) at each time step. Newton-Raphson iteration generally used.

  18. System-Based Approaches Stiff System: A system with both fast and slow dynamics Stiffly Stable Integration Algorithm: the ability to increase the time step after fast transients subside Stiffly Stable Algorithms are implicit!

  19. System-Based Approaches Computational Complexity

  20. System-Based Approaches Dilemma

  21. System-Based Approaches Simulink Algorithms Shampine and Reichelt, The MATLAB ODE Suite, SIAM J. Sci. Comput., Vol. 18, No. 1, pp. 1-22, January 1997.

  22. Simulation Approaches • Circuit-Based Approaches (Spice, Saber, PSIM, Simplorer) • System-Based Approaches (Simulink, ACSL, Dymola) • Block-diagram and/or differential equation oriented • Extensive set of tool boxes including • ASMG (Simulink, ACSL) • Power System Blockset (Simulink) • … • Finite-Element-Based Approaches (Ansys, Maxwell, …)

  23. Finite-Element Based Approaches FEA 4000-10000 Nodes

  24. Conventional Parallel Computing Paradigm

  25. Conventional Parallel Computing Paradigm

  26. Conventional Parallel Computing Paradigm

  27. Conventional Parallel Computing Paradigm • At best m-fold reduction in computation time assuming zero communication latency • Computational gain further bounded by Amdahl’s Law where serial portion therefore

  28. Distributed Heterogeneous Simulation (DHS)

  29. DHS Definition • Synchronized interconnection of any number of dynamic subsystem simulations • Developed using any combination of programs/languages • Implemented on: • Single computer/workstation/supercomputer • Local area network (Intranet) • Wide area network (Internet)

  30. Sample DHS Computer Setup

  31. DHS Concept Much better than M-fold (potentially M3) improvement in speed

  32. DHS Links Environment

  33. Flexibility of DHS • Heterogeneous platforms (Windows, Unix, Linux, ...) • Heterogeneous languages (ACSL, MATLAB/Simulink, Saber, EASY5, C, C++, FORTRAN, Java,…) • Heterogeneous simulation approaches (single-rate, multi-rate, state model based, resistor-companion, finite difference/element,...) • Heterogeneous networks (Ethernet, SCI, ScramnetTM, MyrinetTM,...)

  34. Key Advantages of DHS • Use “best” language for each component/subsystem • Proprietary information protected • Super-linear increase in computational speed across a network of desktop computers • No need to translate models into common language • Legacy code can be used directly • Conducive to team design/analysis • Remote interconnection • Eliminate need to develop average-value models for system stability assessment • Real-time (hardware-in-the-loop) capability for some systems • System Integrator(s) do not have to be familiar with the language(s) used to create subsystem simulation(s)

  35. More-Electric Aircraft Power System Optimum Allocation

  36. Optimum Allocation

  37. Optimum Allocation 18.5 speedup with 4 computers

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