power electronics and modelica
TRANSCRIPT
10/14/2002
A MODELICA-Based Object-Centric Virtual Power
Electronics Laboratory
Janhavi Agashe V.V.Sastry
V.Ajjarapu S.S.Venkata
Dept. Of Electrical & Computer Engineering
Iowa State University
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Outline
Power Electronics SimulatorsObject-Oriented Modeling Language – ModelicaModeling of Components in ModelicaVarious Models DevelopedSimulation ResultsConclusions
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Inter-Disciplinary Nature of Power Electronics
Power Electronics
Modeling &Simulation
System &Control theory
System Area
Circuit Theory
Electric machines
Power Systems
Electromagnetics
Analog Electronics
Signal Processing
Solid-State Physics
Digital Electronics
Low Power Area High Power Area
PowerElectronics
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Power Electronics Simulators
A simulator for power electronic systems should Have event handling capabilities. Handle hybrid/ mixed-mode systems. Support multi-domain modeling.
Widely used simulators: SABER, PSPICE, MATLAB/SIMULINK etc. Lack of Object-oriented features Closed modeling environment
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Object-oriented Modeling Language - Modelica
Developed by the Modelica Association, GermanyKey Features Object-oriented modeling language
Hierarchical structuring Reuse Effective in solving large and complex
models Open Modeling Environment
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Object-oriented Modeling Language - Modelica
Additional Features Acausal modeling
Ports are not committed to ‘input’ and ‘output’ early in the modeling/design process
Simpler models More efficient simulation
Multi-domain Electrical circuits, multi-body systems,
drive trains, hydraulics, thermodynamic systems
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Object-oriented Modeling Language – Modelica
Additional Features (contd.) Several formalisms
ODE, DAE, bond graphs, finite state automata, state charts
Graphical user interfaces Icons representing model components Menu driven interface for modeling and
simulation Standardization effort
Group of internationally recognized and experienced researchers and companies worked for language and model development
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Modeling of Components in Modelica
Model is derived as an extension of some base class using the “extends” statement
Required variables are declared Necessary equations are defined in
the “equation” section The “annotation” section defines
the graphical symbol i.e. icon for the model
The file is saved as “*.mo”
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Modeling of Components in Modelica
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Thyristor Model in Modelica
model Thyristor constant Boolean DymolaCompatibility=true; extends Modelica.Electrical.Analog.Interfaces.ThreePin; Real Gate; Real u; Real GOp = 1.E-5; Real RCl = 1.E-5; Real i; Boolean GATE; Boolean Op(start=true);equation cont.v = Gate; u = p.v-n.v; i=p.i; 0=p.i+n.i; GATE = if (Gate < 1.0) then false else true; 0 = if Op then i - GOp*(p.v - n.v) else (p.v - n.v) - RCl*i; when (not (Op) and i < 0) or (Op and u > 0 and GATE) then new(Op) = (not (Op) and i < 0) or (Op and not ((u > 0 and
GATE))); end when; end Thyristor;
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Models in the Power Electronics Library
TwoPin ThreePin
OnePort TwoPort Others
Diode,
TwoPin Switch,
Measurement Templates,
Thyristor,
Thyristor Firing Circuit,
ThreePin Switch,
Electrical to Control,
Control to Electrical,
Average Model for Rectifier,
RMS Model for Inverter
DC Machine,
Induction Machine
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Architecture of Simulator
Front-end Pre-processing tool that helps effective
understanding and modeling DYMODRAW
Simulation Engine For conversion DAE’s into state space form and
solving them symbolically or with efficient numerical techniques.
DYMOSIM. Any other simulator like ACSL, SIMULINK, etc. can also be used.
Post-processing tool Visualization of dynamic behavior, 2-D or 3-D
graphical view or animation. DYMOVIEW
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Architecture of Simulator
Graphical Front-
end
Post-processing Tool
Simulation Engine
Object-oriented Modeling
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Step by Step Simulation Procedure
Various Libraries
Switch Library
Single Thyristor
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Step by Step Simulation Procedure
Connection of components
Entire Circuit & its Translation
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Step by Step Simulation Procedure
Simulation Control Plot Window & Output Variables
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Single-Phase Bridge Rectifier
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Single-Phase Bridge Rectifier
Firing Angle = 45 degrees
Firing Angle = 30 degrees
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Buck Chopper
Vout
iout
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Buck Chopper
Duty Ratio = 0.75
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
MODELICA Based EE 452 Laboratory Experiments
Single Phase Thyristor RectifierThree Phase Thyristor RectifierBuck ChopperBoost ChopperSingle Phase Square-Wave InverterThree Phase Square-Wave InverterChopper-fed DC Motor DriveV/F control of Induction Motor
10/14/2002 North American Power Symposium 2002, Arizona State University,
Tempe
Conclusions
Object-oriented modeling language enabled reuse of models, hierarchical structuring and easy maintenance of modelsThe power electronics library using MODELICA has been developed at Iowa State UniversityEE 452 experiments earlier written in DYMOLA have been designed around the new MODELICA library