Method for ascertaining an internal resistance of an electrical energy accumulator
First Claim
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1. A method for ascertaining an internal resistance of an electrical energy accumulator, the method comprising:
- performing an analog to digital conversion of an analog voltage signal and an analog current signal of the electrical energy accumulator in order to obtain digital voltage values and digital current values;
filtering the digital voltage values and the digital current values through a band-pass filter around a zero-phase frequency in order to obtain filtered voltage values and filtered current values,checking whether the following calculation prerequisites are satisfied;
a first calculation prerequisite in which the band-pass filter is initialized,a second calculation prerequisite in which a peak current value together with an associated instant of the peak current value is ascertained from the filtered current values;
a third calculation prerequisite in which an amount of the peak current value is greater than an amount of a threshold current value, the amount of the threshold current value being greater than an amount of a minimum threshold current value by which a zero-phase resistance with a predefined maximum deviation from an actual internal resistance is able to be calculated;
a fourth calculation prerequisite in which the filtered voltage value at the previously ascertained instant is a peak voltage value; and
a fifth calculation prerequisite in which the peak current value and the peak voltage value have the same algebraic sign;
checking the calculation prerequisites on an one after the other basis, wherein the first calculation prerequisite is additionally able to be checked at any other arbitrary point during the checking step;
ending the method if one of the calculation prerequisites is not satisfied;
calculating the zero-phase resistance from the peak voltage value and the peak current value if the method was not yet ended previously; and
providing the zero-phase resistance as an internal resistance of the electrical energy accumulator to be determined if the method was not yet ended previously.
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Abstract
A method is described for ascertaining an internal resistance of an electrical energy accumulator. For this purpose, an analog voltage signal and an analog current signal are subjected to an analog to digital conversion and subsequently to band-pass filtering in order to obtain filtered voltage values and filtered current values. These are then checked with regard to different calculation prerequisites, whereupon a zero-phase resistance is calculated. Then, the calculated zero-phase resistance is supplied as internal resistance.
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7 Claims
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1. A method for ascertaining an internal resistance of an electrical energy accumulator, the method comprising:
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performing an analog to digital conversion of an analog voltage signal and an analog current signal of the electrical energy accumulator in order to obtain digital voltage values and digital current values; filtering the digital voltage values and the digital current values through a band-pass filter around a zero-phase frequency in order to obtain filtered voltage values and filtered current values, checking whether the following calculation prerequisites are satisfied; a first calculation prerequisite in which the band-pass filter is initialized, a second calculation prerequisite in which a peak current value together with an associated instant of the peak current value is ascertained from the filtered current values; a third calculation prerequisite in which an amount of the peak current value is greater than an amount of a threshold current value, the amount of the threshold current value being greater than an amount of a minimum threshold current value by which a zero-phase resistance with a predefined maximum deviation from an actual internal resistance is able to be calculated; a fourth calculation prerequisite in which the filtered voltage value at the previously ascertained instant is a peak voltage value; and a fifth calculation prerequisite in which the peak current value and the peak voltage value have the same algebraic sign; checking the calculation prerequisites on an one after the other basis, wherein the first calculation prerequisite is additionally able to be checked at any other arbitrary point during the checking step; ending the method if one of the calculation prerequisites is not satisfied; calculating the zero-phase resistance from the peak voltage value and the peak current value if the method was not yet ended previously; and providing the zero-phase resistance as an internal resistance of the electrical energy accumulator to be determined if the method was not yet ended previously. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification