Minimum inductance and winding loss

General minimum inductance

Use this when Vin, Vo, ΔI, and fsw are all nonzero. It is the operating-point inductance.

Lmin = Vin*(Vo-Vin)/(ΔI*fsw*Vo)

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Minimum inductance needs Vin, Vo, ΔI, and fsw.

Half-duty shortcut

Use this only when the input is half the output. It is not a second design result at other duty ratios.

Lhalf = Vo/(4*ΔI*fsw)

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Dowell winding factor Fr

Dowell Fr applies when resistivity, frequency, wire diameter, copper factor, and layer count are nonzero.

Fr = xi*[(sinh(2*xi)+sin(2*xi))/(cosh(2*xi)-cos(2*xi)) + (2*(m^2-1)/3)*((sinh(xi)-sin(xi))/(cosh(xi)+cos(xi)))], xi = (d_wire/delta)*sqrt(pi/4)*eta

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Fr is a dimensionless ratio.

Winding factor needs ρ, f, wire diameter, η, and layer count.

delta = sqrt(rho/(pi*f*mu0)), mu0 = 4*pi*1e-7

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Magnetizing force

H = 0.4*pi*N*Ipk/le. le is in cm, so H is in oersted (Oe).

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Core loss density

Pcore = Kfe*f^α*Bpk^β applies only after you enter Kfe, alpha, beta, frequency, and Bpk. No material table is assumed.

Pcore = Kfe * f^alpha * Bpk^beta

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Core loss is not shown because the material coefficients were not entered. That is not a zero loss.