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1. Welcome to the Ansoft Web SeminarPExprt/Maxwell 2D/SIMPLORER: Buck Converter/TransformerMark ChristiniEM Application Engineering christini@ansoft.com Starting in:

2. Buck Converter Design Process 1) Manually select the topology 2) Use Simplorer to simulate the SMPS model 3) Use PExprt to design inductor 4) Use PEmag to generate detailed netlist model 5) Import PEmag model into Simplorer 6) Use Simplorer to simulate the PEmag model 7) Use Simplorer (transient) for load step test 8) Use Simplorer (AC) to design feedback loop 9) Use Simplorer (transient) to do feedback loop test and verify performance SimplorerPExprt PEmag Simplorer

3. Step 1: Select the topology Buck Converter Decide to use either average or switch level Buck Converter

4. Step 2: Simulate in Simplorer with SMPS library Use switch level Buck Converter from SMPS library Change duty cycle and inductor value to achieve desired output voltage Open and run in Simplorer

5. Easy transition from Simplorer to PExprt Step 3: Design Inductor with PExprt Build a waveform based inductor or buck converter in PExprt

6. Run the PExprt model and select the design you prefer Step 3: Design Inductor with PExprt PExprt design results, including constructive data Open e03_Buck.cia and run in PExprt

7. Generate a 1D Analytical or a 2D FEA based model Step 4: Generate Model with PExprt Modeler [PEmag] Can include core non-linear effects using Jiles-Atherton model if the core is operating in the nonlinear range (usually this is a bad design) Open and run in PEmag

8. Step 5: Import PExprt Model into Simplorer Use Simplorer PExprt link to substitute ideal inductor with PExprt model Open original buck converter and import PExprt .sml file

9. Step 6: Simplorer Simulation With PExprt Model PExprt Model and Symbol Simulate the PExprt model in Simplorer (Or open .ssh with PExprt model already imported and re-run)

10. Step 7: Load Step Test: Feedback loop is needed Load step reduces current and device moves to discontinuous mode Non-Regulated Output Voltage Spike occurs since no control loop is used Open and run load step case in Simplorer – Transient solver

11. Step 8: Design Feedback Loop in frequency domain This controls duty cycle of switch to maintain constant output voltage Add PID controller from the SMPS library Design of the control loop with AC analysis of the Converter Specifically, select R and C in the PID controller Open and run load step case in Simplorer – AC solver

12. Finally, return to the time domain analysis to see how the buck converter performs Step 9: Feedback Loop Test: Simplorer Time Domain PID regulator from the SMPS library Load Step Regulated Output Voltage Open and run load step case in Simplorer – Transient solver with PID control

13. Conclusions • Power converters, such as Buck Converters, can be designed from start to finish using Ansoft tools • Simplorer can be used for preliminary average SMPS design • PExprt can design the inductor, based on performance specifications • PEmag can refine the chosen inductor design • Simplorer can evaluate the performance of the entire converter design, including feedback analysis