Prerequisites: Steady-state converters
This original software-only lab links steady-state reasoning to a reproducible calculation. It does not require a commercial licence, an API key or hardware. Python 3.10+ and its standard library are sufficient.
Before starting, explain voltage, current, power, duty ratio, inductor continuity and volt-second balance. Ask your tutor to return to the prerequisite bridge if any of those are unfamiliar. Knowing a formula alone is not evidence of readiness.
Use a synthetic 24 V to 12 V, 30 W ideal converter, switching at 100000 Hz with 0.00015 H inductance. Assume continuous conduction, periodic steady state and small output voltage ripple. Do not interpret these as a production design.
- Predict the duty ratio using average inductor voltage of zero.
- Calculate average output current from power and voltage.
- Calculate on-time current rise:
(Vin - Vout) * duty / (L * frequency). - Run
python labs/buck_open.pyfrom the Academy checkout. - Compare your results with the JSON quantities: duty 0.5, current 2.5 A and peak-to-peak ripple 0.4 A. Explain why minimum current is positive.
- Double frequency with
--frequency 200000. Predict the ripple before running. - Try
--power 0.01. The script rejects the continuous-conduction assumption. Explain why a positive voltage ratio alone does not justify the CCM model.
Record inputs, assumptions, software version, command, output and discrepancies. No efficiency, losses, measured temperature or device suitability is predicted. The next experiment is a switched-circuit simulation with ngspice; compare step size and steady-state windows before interpreting solver waveforms. The AIPE Simulation Skills repository provides that workflow. MATLAB/PLECS variants are optional extensions with separate licences and model-validation requirements.
To pass, derive the voltage balance and explain an assumption failure without copying the answer. A tutor should record assisted and independent performance separately in the learner’s local record, never the public repository.
Continue: Dynamics, transfer functions and control