METHOD FOR DETERMINING A MODEL ERROR IN A MATHEMATICAL MODEL OF AN ELECTRICAL ENERGY STORAGE UNIT

Abstract

The invention relates to a method for determining a model error in a mathematical model of an electrical energy storage unit, which method comprises the following steps: a) providing a mathematical error model for determining the model error in the mathematical model, wherein the mathematical error model is provided in at least a two-part form, wherein a first model error of an open-circuit voltage curve of the mathematical model of the electrical energy storage unit is modelled by the first part of the error model, and a second model error of a voltage curve of the mathematical model is modelled on the basis of an electrical current by the second part of the error model; b) determining at least one current value, wherein the electrical current flows in the electrical energy storage unit; c) applying the determined current value to the mathematical error model as the input value for the mathematical error model; d) determining the model error of the mathematical model as an output value for the mathematical error model, wherein the model error is dependent on the at least two part-models.

Claims

1. A method for determining a model error (13) in a mathematical model of an electrical energy storage unit (31), the method comprising: a) providing a mathematical error model (10) for establishing the model error in the mathematical model, wherein the mathematical error model (10) is provided at least in two-part form, wherein a first model error of an open-circuit voltage characteristic of the mathematical model of the electrical energy storage unit (31) is modeled by the first part (11) of the error model, and a second model error of a voltage characteristic of the mathematical model is modeled on the basis of an electrical current by the second part (12) of the error model; b) establishing a current value, wherein the electrical current flows in the electrical energy storage unit (31); c) applying the established current value to the mathematical error model (10) as input value of the mathematical error model (10); and d) determining the model error (13) of the mathematical model as an output value of the mathematical error model, wherein the model error (13) is dependent on the at least two submodels (11, 12).

2. The method as claimed in claim 1, wherein the model error (13) is determined in step d) by a summation of the two submodel errors of the two submodels (11, 12).

3. The method as claimed in claim 1, wherein the mathematical model of the electrical energy storage unit (31) is included by the mathematical error model (10).

4. The method as claimed in claim 1, wherein the second part (12) of the mathematical error model (10) is formed by at least one first-order or higher-order time-delay element, wherein the submodel error of the second part (12) is formed by means of a weighting of the output of the at least one time-delay element.

5. The method as claimed in claim 1, wherein a modeling of an open-circuit voltage hysteresis is included by the first part (11) of the error model.

6. The method as claimed in claim 1, wherein a temperature dependence is exhibited by the first part (11) of the error model and/or by the second part (12) of the error model.

7. (canceled)

8. A non-transitory, computer-readable storage medium containing instructions that when executed on a computer cause the computer to determine a model error (13) in a mathematical model of an electrical energy storage unit (31), by: a) providing a mathematical error model (10) for establishing the model error in the mathematical model, wherein the mathematical error model (10) is provided at least in two-part form, wherein a first model error of an open-circuit voltage characteristic of the mathematical model of the electrical energy storage unit (31) is modeled by the first part (11) of the error model, and a second model error of a voltage characteristic of the mathematical model is modeled on the basis of an electrical current by the second part (12) of the error model; b) establishing a current value, wherein the electrical current flows in the electrical energy storage unit (31), c) applying the established current value to the mathematical error model (10) as input value of the mathematical error model (10); and d) determining the model error (13) of the mathematical model as an output value of the mathematical error model, wherein the model error (13) is dependent on the at least two submodels (11, 12).

9. A device (22) for determining a model error (13) in a mathematical model of an electrical energy storage unit (31), the device comprising a computer configured to: a) provide a mathematical error model (10) for establishing the model error in the mathematical model, wherein the mathematical error model (10) is provided at least in two-part form, wherein a first model error of an open-circuit voltage characteristic of the mathematical model of the electrical energy storage unit (31) is modeled by the first part (11) of the error model, and a second model error of a voltage characteristic of the mathematical model is modeled on the basis of an electrical current by the second part (12) of the error model; b) establish a current value, wherein the electrical current flows in the electrical energy storage unit (31); c) apply the established current value to the mathematical error model (10) as input value of the mathematical error model (10); and d) determine the model error (13) of the mathematical model as an output value of the mathematical error model, wherein the model error (13) is dependent on the at least two submodels (11, 12).

10. An electrical energy storage system (30), comprising an electrical energy storage unit (31) and a device (32) as claimed in claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Advantageous embodiments of the invention are illustrated in the figures and explained in more detail in the description below.

[0028] In the drawings:

[0029] FIG. 1 shows a schematic illustration of a mathematical error model in a two-part form in accordance with one embodiment;

[0030] FIG. 2 shows a flow chart of the disclosed method in accordance with one embodiment; and

[0031] FIG. 3 shows a schematic illustration of the disclosed electrical energy storage system in accordance with one embodiment.

[0032] Identical reference symbols in all of the figures denote identical device components or identical method steps.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a schematic illustration of a mathematical error model 10 in two-part form in accordance with one embodiment. In this case, a first model error of an open-circuit voltage characteristic of a mathematical model of an electrical energy storage unit is modeled by the first part 11 of the error model 10. The second part 12 of the error model 10 models a second model error of a voltage characteristic of the mathematical model of the electrical energy storage unit on the basis of an electrical current, i.e., when an electrical current or current value is applied to the mathematical model.

[0034] The second submodel 12 is in this case formed by a multiplication of various voltage values of the mathematical error model 10 by in each case one constant and by subsequent absolute value generation and summation of the resulting values. This is illustrated schematically by the three blocks in the second submodule 12. The corresponding voltage values are in this case represented symbolically by the arrow 14. This results in the first model error.

[0035] The first submodel 11 is in this case formed by a data-based family of characteristics 16 in which a corresponding model error err2 of the open-circuit voltage characteristic is assigned to each state-of-charge value SOC of an electrical energy storage unit. Depending on the present state of charge of the electrical energy storage unit, therefore, the corresponding model error err2 results, which is in this case higher, for example, in the case of lower state-of-charge values. The corresponding state-of-charge value is in this case represented symbolically by the arrow 15. This results in the second model error.

[0036] A model error 13 of the mathematical model of the electrical energy storage unit then results from the summation of the two model errors of the submodels 11, 12.

[0037] FIG. 2 shows a flowchart of the disclosed method for determining a model error in a mathematical model of an electrical energy storage unit in accordance with one embodiment.

[0038] In this case, in a first step S21, a mathematical error model is provided for establishing the model error of the mathematical model. The error model is present in at least two-part form. A first model error of an open-circuit voltage characteristic of the mathematical model is modeled by the first part of the error model. A second model error of a voltage characteristic of the mathematical model is modeled on the basis of an electrical current by the second part of the error model.

[0039] In a second step S22, at least one current value is established, wherein the electrical current flows in the electrical energy storage unit. Therefore, the current actually flowing in the electrical energy storage unit is established in order to be able to use it correspondingly in the mathematical model.

[0040] In a third step S23, the established at least one current value is used as input value of the mathematical error model, and therefore said current value is applied to the mathematical error model in order to be able to perform a corresponding model evaluation.

[0041] In a fourth step S24, the model error of the mathematical model is determined as output value of the mathematical error model, wherein the model error is dependent on the at least two submodels.

[0042] FIG. 3 shows a schematic illustration of the disclosed electrical energy storage system 30 in accordance with one embodiment. In this case, the electrical energy storage system 30 comprises an electrical energy storage unit 31 and a device 32 for determining a model error in a mathematical model of the electrical energy storage unit 31. The device 32 can in this case establish, for example, the current which is flowing through the electrical energy storage unit 31.