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PExprt
Modeling
Procedure
Overview
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Power Electronics Expert (PExprt)® is an interactive, performance based
design tool that uses analytical expressions to design magnetic
components, such as transformers and inductors.
Standard libraries of magnetic cores, bobbins, insulators, and conductors
allow you to define the model to your exact specifications.
Using PExprt, you can design: inductors, multi-winding transformers,
coupled inductors, and flyback components.
Optimize constructive parameters, such as core size, core material,
number of turns, air gap length, wire gauge, and number of parallel turns.
Overview (cont.)
Calculate performance parameters, such as
winding losses, core losses, flux density, DC and
AC resistance, Irms currents, magnetizing
inductance, leakage inductance, and temperature
rise.
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Consider complex effects, such as skin and
proximity effects, fringing flux near the air-gap for
energy calculations
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Calculate winding losses based on FEA field
solution and core losses.
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PExprt also includes the Pemag modeling module,
a powerful magnetic analysis module based on
finite element analysis. This module conducts a
detailed analysis of geometry, frequency, and
material
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Generate model netlists for SIMPLORER®,
Maxwell SPICE®, PSpice®, and Saber® electrical
simulators to perform a complete system
9/1/04 simulation of the entire device.
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Step 1: Choose device type
Choose the appropriate device type
(1 of 12 options) and assign
appropriate inputs
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Inductor, Transformer, Coupled
Inductor and Flyback
Choose either Waveform based
or Converter based
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12
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Waveform Based Inductor (option 1)
Inputs:
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Voltage
Waveform
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Voltage Value
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Iaverage
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Frequency
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Inductance
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Duty Cycle
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Conduction
Mode
Note: Inductance is
known
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Converter Based Buck Inductor (option 2)
Inputs:
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Input Voltage
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Output Voltage
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Output Power
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Current Ripple
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Ripple %
Note: Inductance is
unknown
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Waveform Based Transformer (option 3)
Inputs:
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Primary Voltage
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Turns Ratio
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Power
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Frequency
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Voltage Shape
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Duty Cycle
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Voltage
Waveform
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Converter Based PushPull Transformer (option 9)
Inputs:
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Input Voltage
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Output Voltage
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Output Power
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Switching Freq.
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Duty Cycle
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Waveform Based Coupled Inductor (option 10)
Inputs:
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Input Voltage
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Average
Current
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Inductance
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Turns Ratio
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Frequency
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Duty Cycle
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Conduction
Mode
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Waveform Based Flyback (option 11)
Inputs:
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Input Voltage
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Average
Current
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Inductance
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Turns Ratio
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Frequency
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Duty Cycle
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Conduction
Mode
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Converter Based Flyback (option 12)
Inputs:
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Input Voltage
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Switching
Frequency
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Output Voltage
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Output Power
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Ripple Current
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Turns Ratio
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Waveform
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Step 2: Select Design Inputs
The design inputs vary depending on the device being modeled:
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Gap, Geometry (concentric, planar, toroidal), Bobbin, Permeability,
Ventilation type, Radiation and Convection, Ambient Temperature,
Winding Setup (1D or 2D), Winding Efficiency, Fringing gap
energy, Maximum parallel turns, fixed gap, margin tape, limit
values
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Step 3: Modeling Options
The modeling options help to improve the accuracy of the results:
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Winding losses calculation, Core losses calculation, Optimization
method, listing results, apply restrictions, number of harmonics
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Step 4: Select Library
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PExprt contains seven
manufacturer libraries:
AVX, Epcos, Ferroxcube,
Magnetics, Micrometals,
Steward, and TDK
Only one library can be used
for a given design
To select a library, highlight it
and drag it down to the
Design Library icon
Once copied to the Design
Library, the elements can be
modified
Step 5: Select Core Shape
PExprt contains eleven
cores shapes
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For Concentric and
Planar, choose:
POT, RM, EE, EI,
ETD, EFD, UU,
EP, PQ, or UI
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For Toroidal,
choose only
toroidal cores
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Step 6: Select Core Size
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To select a core, right mouse click on
the core displaying a symbol
To modify core properties or
dimensions, double click on the core
Step 7: Select Bobbin
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If used, select a bobbin to match the core used
Step 8: Select Conductors
PExprt contains five
conductor types, depending
on the geometry chosen
(concentric, planar, or
toroidal)
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For Concentric, choose: Litz,
Round, Foil, or Square
For Planar, choose only
planar
For Toroidal, choose Litz or
Round
Available Conductor Types
Litz
Foil
Planar
Round
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Square
Step 9: Select Core Material
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PExprt contains two
basic material types:
iron powder and
ferrite
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For each core
material, the electrical
properties and core
loss parameters can
be specified
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Step 10: Start the Design Process
Use either“Calculations/Start Design
Process” or click on the button at the
toolbar
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Automatic selection of core shape, wires,
and core material
If you do not specify the
core shape, conductors,
and core material, the
program will do this
automatically.
Several of each component
are chosen, instead of the
complete library
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Designing the component…
A progress bar shows the
status of the design
procedure.
When completed, the
number of valid designs
and number of attempted
designs are listed.
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Step 11: Explore the list of results
To sort a
particular column,
such power loss,
click on the top of
the column
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Step 12: Explore the performance results
Select
Performance
Results to
examine the
losses,
inductances,
resistance, flux
density,
incremental
permeability, and
temperature
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Step 13: Explore the construction results
Select
Construction
Results to see the
chosen: core size,
bobbin, core
material, gap,
wire, winding
turns, and parallel
paths
Double click on
core size, bobbin,
core material, or
wire to check the
details of the
component
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Step 14: View Complete report
Select Reports >
Complete Report to see
summary of design
+---------------------------------------------------+
| PExprt Magnetic Component Report
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Generated by PExprt
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Copyright UPM-Ansoft 1992-2004
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Version 6.0.15
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+----------------------------------------------------+
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Waveform Description
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+----------------------------------------------------+
Square Voltage Waveform
Positive Voltage Value: 38.000 V
Negative Voltage Value: 12.000 V
Frequency: 70 kHz
Continuous Conduction Mode
Average Current Value: 30.000 A
Current Ripple Value: 6.500 A
Specified Inductance Value: 20.044 uH
Duty Cycle (ton/T): 24 %
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+----------------------------------------------------+
|
Design Inputs
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+---------------------------------------------------+
Gap at central leg only
Use Bobbin: No
Planar Component
2D Winding strategies are feasible
Maximum number of parallel turns: 10
Heat transfer method: Normal
Winding efficiency defined by turns spacing:
Intralayer spacing: 25 um
Interlayer spacing: 25 um
Window filling defined by window occupancy
(Wire area/Window area):
+----------------------------------------------------+
|
Modeling Options
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+----------------------------------------------------+
Winding losses calculated accounting for skin
effect
Number of harmonics to be considered: 512
Optimization of solutions for each parallel
+------------------------------------------------------+
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Design Performance Results
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+------------------------------------------------------+
Losses Distribution:
-------------------Winding Losses: 2.050 W
Core Losses: 32.582 mW
Total Losses: 2.083 W
Flux Density:
------------Variation of B: 47.6888 mT
Maximum B: 243.946 mT
+------------------------------------------------------+
|
Design Constructive Results
|
+------------------------------------------------------+
Design Library: Ferroxcube_Design
Core Size: E71/33/32
Core Material: 3F3
Bobbin: None
Wire: Copper_70um_7mm
Number of Turns: 4
Number of parallel turns: 10
Gap: 641.65 um
Step 15: Create a netlist model
Select Modeler >
Generate Model to create
a netlist for the design.
Choose Analytical, FEA
with capacitance, or FEA
without capacitance for
the model type.
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Step 16: View Simplorer Netlist
Choose Modeler > View
Netlist > Simplorer to see
the netlist for the design
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Step 17: Import into Simplorer
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