Magnetic Components

Reference Guide

Constraints

MUST DO

• Always refer all impedances to the same winding before writing MNA stamps.
• Include leakage inductance — it causes voltage spikes at switch turn-off and is critical for LLC tank design.
• Check B_pk ≤ B_sat at all operating points, including transient startup and overload.
• Use iGSE for core loss estimation with switching (non-sinusoidal) waveforms; plain Steinmetz overestimates.
• Validate with volt-second balance check every steady-state cycle in simulation.

MUST NOT DO

• Use an ideal transformer model (just turns ratio) for any analysis that includes leakage, saturation, or core loss.
• Forget to update the nonlinear inductor stamp after each Newton-Raphson iteration — saturation makes it iteration-dependent.
• Mix referred and unreferred values in the same stamp row/column.
• Apply the Steinmetz equation to DC-biased cores without accounting for the shifted B-H operating point.
• Ignore the air-gap contribution to inductance in gapped cores: L_gap = μ_0·N²·A_c/l_g.

Output Template

For magnetic component modeling tasks, provide:

1. Core and winding parameters (geometry, material, turns, wire gauge).
2. Equivalent circuit with all referred values.
3. Saturation check: B_pk at nominal and peak current vs. B_sat.
4. MNA stamp structure (which rows/columns affected, with/without nonlinear terms).
5. Core loss estimate (Steinmetz or iGSE) and copper loss breakdown.
6. Validation criteria (volt-second balance, flux waveform shape, loss budget).

Primary References

• Kazimierczuk — High-Frequency Magnetic Components (2nd ed.)
• Erickson & Maksimovic — Fundamentals of Power Electronics, Chapter 13–14
• Jiles & Atherton — Theory of ferromagnetic hysteresis, J. Magn. Magn. Mater. 61 (1986)
• Venkatachalam et al. — Accurate prediction of ferrite core loss with nonsinusoidal waveforms, COMPEL 2002