Method of determining the impedance of an electrochemical system
First Claim
1. A method for determining the complex impedance Z(fm) of a non-stationary electrochemical system, characterized in that it comprises the steps of:
- setting the system to a selected voltage state and applying a sinusoidal signal of frequency fm thereto,measuring, immediately after, successive values of the voltage and of the current at regular time intervals Δ
T,calculating the discrete Fourier transforms of the voltage (E(f)) and of the current (I(f)), the voltage transform being calculated for the sole frequency fm of the sinusoidal signal and the current transform being calculated for frequency fm and for two adjacent frequencies fm−
1 and fm+1 on either side of frequency fm, andcalculating the impedance according to the following formula;
Z(fm)=E(fm)/I*(fm)where I* designates a corrected current such that;
Re[I*(fm)]=Re[I(fm)]−
{Re[I(fm+1)]+Re[I(fm−
1)]}/2
Im[I*(fm)]=Im[I(fm)]−
{Im[I(fm+1)]+Im[I(fm−
1)]}/2.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention relates to a method of determining the complex impedance Z(fm) of a non-steady electrochemical system, comprising the following steps consisting in: bringing the system to a selected voltage condition and applying a sinusoidal signal with frequency fm thereto; immediately thereafter, measuring successive values for voltage and current at regular time intervals ?T; calculating the discrete Fourier transforms for voltage (E(f)) and current (I(f)), the voltage transform being calculated for the single frequency fm of the sinusoidal signal and the current transform being calculated for frequency fm and for two adjacent frequencies fm−1 and fm+1 on either side of frequency fm; and calculating the impedance using the following formula: Z(fm)=E(fm)/I*(fm), wherein I* denotes a corrected current such that Re[I*(fm)]=Re[I*(fm)]−(Re[I(fm+1)]+Re[I(fm−1)]2, Im[I*(fm)]=Im[I(fm)]−Im[I(fm+1)]+Im[I(fm−1)])/2.
-
Citations
2 Claims
-
1. A method for determining the complex impedance Z(fm) of a non-stationary electrochemical system, characterized in that it comprises the steps of:
-
setting the system to a selected voltage state and applying a sinusoidal signal of frequency fm thereto, measuring, immediately after, successive values of the voltage and of the current at regular time intervals Δ
T,calculating the discrete Fourier transforms of the voltage (E(f)) and of the current (I(f)), the voltage transform being calculated for the sole frequency fm of the sinusoidal signal and the current transform being calculated for frequency fm and for two adjacent frequencies fm−
1 and fm+1 on either side of frequency fm, andcalculating the impedance according to the following formula;
Z(fm)=E(fm)/I*(fm)where I* designates a corrected current such that;
Re[I*(fm)]=Re[I(fm)]−
{Re[I(fm+1)]+Re[I(fm−
1)]}/2
Im[I*(fm)]=Im[I(fm)]−
{Im[I(fm+1)]+Im[I(fm−
1)]}/2.- View Dependent Claims (2)
-
Specification