Multi-phase AC Loss Calculation for Air-core Litz Coils

This code analytically generates the total AC loss in a multi-phase system consisting of axisymmetric, cylindrically-wound Litz coils.

This code makes a hoop-turn assumption and therefore doesn't account for the small azimuthal magnetic fields due to coil pitch. Additionally, for internal proximity field calculations a infinitely long straight conductor approximation is used, which become more accurate with larger coil diameters.

Each input vector has length equal to the number of independently excited coils. The only exception is the frequency vector, f, which has length equal to the number of frequencies to be analyzed. This is also the length of the output vectors.

Inputs:

• dbos_c - vector containing the diameter of the bundle's outer surface for each coil [m]
• Dc_c - vector containing each coil's diameter, defined from the center of the bundle [m]
• Nt - vector containing the number of turns in each coil
• ca - vector containing the c/a spacing factor of each coil, defined as: c/a = coil pitch / dbos
• z_c - vector containing the axial position of the top turn for each coil [m]
• ds_c - vector containing the strand diameter used in the Litz bundle for each coil [m]
• Ns_c - vector containing the number of strands in the Litz bundle for each coil
• Ipeak_c - vector containing the peak sinusoidal AC current magnitude in each coil [A]
• phi_c - vector containing the relative phase of the current in each coil [rad]
• f - vector of frequencies to analyze the system at [Hz]

Outputs:

• Ploss - vector containing the total power loss for each input frequency [W]
• Ps - vector containing the power loss due to skin-effect for each input frequency [W]
• Pp - vector containing the power loss due to proximity-effect for each input frequency [W]

The numlays variable may be increased (in integer steps) to increase accuracy with trade-offs in computation time.