PExprt Modeling Procedure

Overview 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. Consider complex effects, such as skin and proximity effects, fringing flux near the air-gap for energy calculations Calculate winding losses based on FEA field solution and core losses. 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 Generate model netlists for SIMPLORER®, Maxwell SPICE®, PSpice®, and Saber® electrical simulators to perform a complete system simulation of the entire device.

Step 1: Choose device type Choose the appropriate device type (1 of 12 options) and assign appropriate inputs Inductor, Transformer, Coupled Inductor and Flyback Choose either Waveform based or Converter based 1 2 3 4 5 6 7 8 9 10 11 12

Waveform Based Inductor (option 1) Inputs: Voltage Waveform Voltage Value Iaverage Frequency Inductance Duty Cycle Conduction Mode Note: Inductance is known

Converter Based Buck Inductor (option 2) Inputs: Input Voltage Output Voltage Output Power Current Ripple Ripple % Note: Inductance is unknown

Waveform Based Transformer (option 3) Inputs: Primary Voltage Turns Ratio Power Frequency Voltage Shape Duty Cycle Voltage Waveform

Converter Based PushPull Transformer (option 9) Inputs: Input Voltage Output Voltage Output Power Switching Freq. Duty Cycle

Waveform Based Coupled Inductor (option 10) Inputs: Input Voltage Average Current Inductance Turns Ratio Frequency Duty Cycle Conduction Mode

Waveform Based Flyback (option 11) Inputs: Input Voltage Average Current Inductance Turns Ratio Frequency Duty Cycle Conduction Mode

Converter Based Flyback (option 12) Inputs: Input Voltage Switching Frequency Output Voltage Output Power Ripple Current Turns Ratio Waveform

Step 2: Select Design Inputs The design inputs vary depending on the device being modeled: 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

Step 3: Modeling Options The modeling options help to improve the accuracy of the results: Winding losses calculation, Core losses calculation, Optimization method, listing results, apply restrictions, number of harmonics

Step 4: Select Library 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 For Concentric and Planar, choose: POT, RM, EE, EI, ETD, EFD, UU, EP, PQ, or UI For Toroidal, choose only toroidal cores

Step 6: Select Core Size 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 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) 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 Square

Step 9: Select Core Material PExprt contains two basic material types: iron powder and ferrite For each core material, the electrical properties and core loss parameters can be specified

Step 10: Start the Design Process Use either“Calculations/Start Design Process” or click on the button at the toolbar

Several of each component are chosen, instead of the complete library 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

A progress bar shows the status of the design procedure. 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.

Step 11: Explore the list of results To sort a particular column, such power loss, click on the top of the column

Step 12: Explore the performance results Select Performance Results to examine the losses, inductances, resistance, flux density, incremental permeability, and temperature

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

Select Reports > Complete Report to see summary of design Step 14: View Complete report Select Reports > Complete Report to see summary of design +---------------------------------------------------+ | PExprt Magnetic Component Report | | Generated by PExprt | | Copyright UPM-Ansoft 1992-2004 | | Version 6.0.15 | +----------------------------------------------------+ | Waveform Description | 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 % +----------------------------------------------------+ | Design Inputs | +---------------------------------------------------+ 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 | Winding losses calculated accounting for skin effect Number of harmonics to be considered: 512 Optimization of solutions for each parallel +------------------------------------------------------+ | Design Performance Results | 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

Select Modeler > Generate Model to create a netlist for the design. 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.

Step 16: View Simplorer Netlist Choose Modeler > View Netlist > Simplorer to see the netlist for the design

Step 17: Import into Simplorer