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Impedance calculation
Posted Jan 29, 2015, 8:56 p.m. EST 1 Reply
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In a 2D axisymmetric model using MEF physics, I have a simple RLC coil group. I'm interested in both the inductance and capacitance of the coil.
COMSOL provides mef.LCoil_1 as a global post-processing value, but does not provide capacitance as a post-processing value. No problem, I figure I'll just calculate it using
C = 2*intWe/(mef.VCoil_1^2)
Naturally, I decided to double-check the inductance value using
L = 2*intWm/(mef.ICoil_1^2)
but this gives exactly 1/2 the value mef.LCoil_1 provides. So can someone help me with the missing factor of 2?
COMSOL provides mef.LCoil_1 as a global post-processing value, but does not provide capacitance as a post-processing value. No problem, I figure I'll just calculate it using
C = 2*intWe/(mef.VCoil_1^2)
Naturally, I decided to double-check the inductance value using
L = 2*intWm/(mef.ICoil_1^2)
but this gives exactly 1/2 the value mef.LCoil_1 provides. So can someone help me with the missing factor of 2?
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1 Reply Last Post Jan 30, 2015, 1:49 p.m. EST
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Posted:
9 years ago
Okay, I figured it out. Because these are AC fields, not DC, the energy is time averaged. The average field is the RMS amplitude (1/sqrt(2)). The energy goes as the average field squared, and thus a factor of 1/2 from the DC formulation.