Methods for determining inductance and resistance of an inductor

Abstract

A resistor (having a resistance of R s ) is connected in series with an inductor whose inductance and/or resistance is desired to be determined. An alternating voltage (such as a sinusoidal voltage) is applied across the series-connected resistor and inductor, wherein the alternating voltage has a frequency ω, a unique maximum or minimum value V m , an average value and a unique crossover of the average value. The voltage V r is measured across the resistor when the alternating voltage is at its maximum or minimum value. The voltage V l is measured across the resistor when the alternating voltage is at its average value. The resistance R L of the inductor is calculated from an equation in which R L is a function of V m , V r , R s and V l . The inductance L of the inductor is calculated from an equation in which L is a function of V l , R l , R s , V r and ω.

1 . A method for determining the inductance L of an inductor comprising the steps of: 
 a) connecting a resistor in series with the inductor, wherein the resistor has a resistance of R s ;    b) applying an alternating voltage having at least one of a triangular waveform and a sinusoidal waveform across the series-connected resistor and inductor, wherein the alternating voltage has a frequency ω, a unique maximum or minimum value V m , an average value corresponding to zero and a unique crossover of the average value;    c) measuring the voltage V r  across the resistor when the alternating voltage is at its maximum or minimum value;    d) measuring the voltage V l  across the resistor when the alternating voltage is at its average value;    e) calculating the resistance R L  of the inductor from an equation in which R L  is a function of V m , V r , R s  and V l  and    f) calculating the inductance L of the inductor from an equation in which L is a function of V l , R l , R s , V r  and ω.    
   
   
       2 . The method of  claim 1 , wherein the inductor is a coil.  
   
   
       3 . The method of  claim 1 , wherein the inductor is a circuit.  
   
   
       4 - 6 . (canceled)  
   
   
       7 . A method for determining the resistance R L  of an inductor comprising the steps of: 
 a) connecting a resistor in series with the inductor, wherein the resistor has a resistance of R s ;    b) applying an alternating voltage having at least one of a triangular waveform and a sinusoidal waveform across the series-connected resistor and inductor, wherein the alternating voltage has a frequency ω, a unique maximum or minimum value V m , an average value corresponding to zero and a unique crossover of the average value;    c) measuring the voltage V r  across the resistor when the alternating voltage is at its maximum or minimum value;    d) measuring the voltage V l  across the resistor when the alternating voltage is at its average value; and    e) calculating the resistance R L  of the inductor from an equation in which R L  is a function of V m , V r , R s  and V l .    
   
   
       8 . The method of  claim 7 , wherein the inductor is a coil.  
   
   
       9 . The method of  claim 7 , wherein the inductor is a circuit.  
   
   
       10 - 12 . (canceled)