Battery simulator accompanied by reduction in demand for electronic components

Abstract

To reduce demand for electronic components forming a battery simulator.SOLUTION: A battery simulator includes: a first electric circuit that provides a first cell voltage for simulating a voltage of a first battery cell; and a second electric circuit that provides a second cell voltage for simulating a voltage of a second battery cell. The first cell voltage is connected to a local circuit ground, and the second cell voltage is connected to the same local circuit ground and connected in series with the first cell voltage in such a way that the local circuit ground forms a pole of the first cell voltage and second cell voltage. A control electronic device is configured to perform closed-loop control of the first cell voltage and second cell voltage. Two cell voltages are driven to perform the control through the single control electronic device, resulting in omission of a component element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] Prior Art A battery simulator is a development system used in the prior art to test the performance of a technical system provided for interaction with a battery, which may for example be a battery management system controlling the charging and discharging processes of the cells of the battery, or an electric motor of an electric vehicle powered by the battery, or a charging station.

[0002] A battery includes a number of battery cells connected in series. Each battery cell is a galvanic cell that generates an individual cell voltage, and therefore the sum of all the cell voltages produces the output voltage of the battery. Correspondingly, battery simulators known in the prior art provide a number of simulated individual closed-loop controllable cell voltages connected in series, and further include a computer model that simulates the electrical behavior of the galvanic cell for each simulated cell voltage to calculate a target setting for each cell voltage.

[0003] The drawing in FIG. 1 shows in a simplified manner the structure of an individual simulated battery cell in a battery simulator according to the prior art from the applicant's product portfolio. A DC voltage converter provides the supply voltage for operating the electrical components, and a voltage regulator applies the simulated cell voltage to a subsection of the basic electrical circuit provided for this purpose and controls this cell voltage in a closed loop to a setpoint value set by the control electronics. The control electronics includes, among other things, measurement technology, a digital isolator, a microcontroller and an auxiliary voltage supply. As mentioned above, a typical battery simulator is designed to simulate a large number of battery cells, so that all individual components of the electrical circuit shown in FIG. 1 are also installed in a corresponding number. Overall, this results in high demands on the electrical components, which leads to a high price and a large space requirement for the battery simulator. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE DISCLOSURE Against this background, the object of the present invention is to reduce the demands on the electrical components forming a battery simulator. [Means for solving the problem]

[0005] In order to achieve the above object, a battery simulator is proposed, which includes a first electric circuit, through which a first cell voltage for simulating the voltage of a first battery cell is dropped, the electric circuit further including control electronics for closed-loop control of the first cell voltage.

[0006] The first cell voltage is connected to a local circuit ground. A second cell voltage for simulating the voltage of a second battery cell is dropped through a second subsection of the first electric circuit. The second cell voltage is likewise closed-loop controlled by the control electronics and connected to the same local circuit ground as the first cell voltage. The second cell voltage is connected in series with the first cell voltage such that the local circuit ground forms a pole of the first cell voltage and the second cell voltage.

[0007] The local circuit ground is a clearly defined common zero potential for the two cell voltages to be simulated, i.e. the first cell voltage and the second cell voltage. A local circuit ground is to be understood as a ground according to the terminology known from electrical engineering, but which is not the global ground of the battery simulator, but in particular a ground which is implemented for this purpose locally in the first electrical circuit, in order to act exclusively as a common zero potential for the first cell voltage and the second cell voltage.

[0008] The electric circuits known in the prior art for simulating battery cells, as described above and shown in FIG. 1, can only simulate one battery cell. In contrast, the first electric circuit according to the invention can simulate two battery cells and requires only slightly higher additional costs of electric components to apply the second cell voltage for the simulation of the second battery cell. The two cell voltages share the electric components of the control electronics as well as the voltage source for the supply voltage. Overall, therefore, a much more efficient utilization of the electric components is achieved in the case of the battery emulator according to the invention. In a battery emulator simulating multiple battery cells based on multiple electric circuits according to the invention, the demands on the control electronics and the local voltage supply are half as high as in the prior art.

[0009] The first electric circuit advantageously comprises a specific local voltage source, in particular a DC voltage converter, arranged to apply to the first electric circuit a supply voltage for the operation of the electric components of the first electric circuit, and further advantageously comprises a first voltage regulator powered by the supply voltage, arranged and configured to apply a first cell voltage to the first subsection and to control it in a closed loop to a first setpoint value, and a second voltage regulator arranged and configured to apply a second cell voltage to the second subsection and to control it in a closed loop to a second setpoint value.

[0010] Since both the first and the second cell voltages are applied to the local circuit ground, it is reasonable for symmetry reasons to invert one of these two cell voltages. That is, for example, if the first cell voltage, defined as positive, is directed towards the local circuit ground, the second cell voltage, defined as positive, should be directed away from the local circuit ground. For this purpose, the first electric circuit advantageously comprises an inverting converter connected in parallel to a first voltage regulator, which is powered by the supply voltage, and a second voltage regulator is powered by the output voltage of the inverting converter. The control electronics is configured to set a first target value for the first voltage regulator such that the first target value is the same as the target setting for the voltage of the first battery cell, and to set a second target value for the second voltage regulator such that the second target value is the same as the negative value of the target setting for the voltage of the second battery cell. The two target settings may, for example, be set by the above-mentioned computer model simulating the electrical behavior of a plurality of galvanic cells.

[0011] To be able to simulate more than two battery cells, the battery simulator preferably further includes at least one second electric circuit in addition to the first electric circuit, the second electric circuit being configured identically to the first electric circuit and providing a third cell voltage to simulate the voltage of a third battery cell and a fourth cell voltage to simulate the voltage of a fourth battery cell, similar to the above. The second electric circuit is electrically connected to the first electric circuit such that the first cell voltage, the second cell voltage, the third cell voltage and the fourth cell voltage are connected in series to simulate four battery cells connected in series together. Similarly, the battery simulator can include essentially any number of electric circuits, all of which are configured identically to the first electric circuit and electrically connected to each other, whereby all cell voltages simulated by the multiple electric circuits are connected in series to simulate a battery of multiple battery cells connected in series.

[0012] The invention will be explained in more detail below on the basis of the drawings. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a simplified block diagram of an electrical circuit known from the prior art for simulating an individual battery cell in a battery simulator. [Diagram 2] FIG. 2 is a simplified block diagram of an electrical circuit according to the present invention for simulating two battery cells in a battery simulator. [Diagram 3] FIG. 3 is a detailed circuit diagram of the electrical circuit shown in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The drawing in Fig. 1 shows in the form of a block diagram an electric circuit known from the prior art for simulating a first battery cell in a battery simulator. A DC-to-DC converter, which is powered by a global voltage supply 2 of the battery simulator, provides as a voltage source 4 a supply voltage for a first voltage regulator 6. The first voltage regulator 6 converts a first cell voltage U Z1 to a first subsection 10 of the electric circuit. The microcontroller 8 transmits the first cell voltage U Z1 The first voltage regulator 6 sets a first target value of the first cell voltage U Z1 The microcontroller communicates via a digital isolator 16 with a computer model implemented outside the electrical circuit that simulates the electrical behavior of the multiple galvanic cells of the battery, and derives from the computer model a first cell voltage U Z1 and transfers this target setting to the first voltage regulator 6 as a target value.

[0015] The differential amplifier 20 is arranged to measure the current intensity of the current flowing through the first subsection 10 and to transfer the measured current intensity via an analog / digital converter 18 to the microcontroller 8. The microcontroller 8 transfers the actual value of the current intensity via a digital isolator 16 to the battery simulator.

[0016] Thus, the electrical circuit includes a number of electrical components that together represent the first cell voltage U Z1 and the first cell voltage U Z1 The control electronics includes, among other things, a digital isolator 16, a microcontroller 8, a digital / analog converter 12, an analog / digital converter 18, a differential amplifier 20, as well as an auxiliary voltage supply 14 providing operating voltages for the electrical components of the control electronics 22.

[0017] The diagram of FIG. 2 illustrates a first cell voltage U Z1 and the second cell voltage U Z2 In the following, only the differences from the electric circuit shown in FIG.

[0018] An inverting converter 24, powered by the voltage supply 4, is connected in parallel to the first voltage regulator 6, which inverts the voltage provided by the voltage supply 4 and supplies the inverted voltage to a second voltage regulator 7. The second voltage regulator 7 converts the second cell voltage U Z2 to the second subsection 11 of the electrical circuit. The microcontroller derives from the computer model the second cell voltage U Z2 and based on the target setting, determining a second cell voltage U Z2to the second voltage regulator, but the control electronics 22 is configured to invert the second target value with respect to the target setting from the computer model. That is, the second voltage regulator transfers as the second target value the second cell voltage U set by the computer model as the second target setting. Z2 Receives the negative value of .

[0019] First cell voltage U Z1 The second cell voltage U Z2 are also connected to a common local circuit ground 23, which therefore Z1 and the second cell voltage U Z2 By inverting the voltage applied to the second voltage regulator 7 by the inverting converter 24 and inverting the second target value, a positive defined second cell voltage U Z2 is directed away from the local circuit ground 23 and the first cell voltage U Z1 is achieved being directed towards the local circuit ground 23.

[0020] The differential amplifier 20 is additionally arranged and configured to measure the current intensity of the current flowing through the second subsection 11 and to transfer the measured current intensity to the microcontroller 8 for transfer to the battery simulator, similar to that described above.

[0021] From the drawing, the second cell voltage U Z2It can be easily seen that only small additional costs of electrical components are required to provide the inverting converter 24, the second voltage regulator 7 and a further measuring resistor. In the battery simulator, several electrical circuits, for example the electrical circuit shown in FIG. 2, are connected to one another in such a way that all cell voltages simulated by the several electrical circuits are connected in series, which results in a long series circuit of simulated cell voltages that can be controlled in a closed loop independently of one another. In conventional battery simulators according to the prior art, each individual cell voltage is assigned its own control electronics 22 and its own voltage source 4. In the battery simulator according to the invention, each of the two cell voltages shares the control electronics 22 and the voltage source 4. This results in a considerable saving of electrical components in a battery simulator that is designed for the simulation of several battery cells.

[0022] 3 shows a detailed circuit diagram of the first electric circuit, without the control electronics 22. A first voltage measuring device 30 configured as a differential amplifier detects the first cell voltage U Z1 The first voltage regulator 6 includes an error amplifier, and a first cell voltage U output from a first voltage measuring device 30 is measured at a first input side of the error amplifier. Z1 The actual value of the first cell voltage U is applied to the second input of this error amplifier, which receives the actual value of the first cell voltage U output by the digital / analog converter 12. Z1 The output voltage of the differential amplifier is applied as a base voltage to one of two transistors, one configured as an NPN transistor and the other as a PNP transistor. The emitter-collector voltages of the two transistors are applied by a voltage source 4.

[0023] Microcontroller 8 is U Z1 As soon as you change the target value for U Z1A difference occurs between the target and actual values ​​of U, which prompts the error amplifier to match the base voltages applied to the NPN and PNP transistors. Z1 The base voltage is increased when the target value of U is higher than the actual value. Z1 The microprocessor 8 is configured to reduce the base voltage if the target value of U is lower than the actual value. Z1 Depending on whether the target value for is increased or decreased, the resistance of the NPN transistor increases and the resistance of the PNP transistor decreases, or the resistance of the NPN transistor decreases and the resistance of the PNP transistor increases.

[0024] Since only one of the two transistors, either the NPN transistor or the PNP transistor, is connected in conduction at any one time, there is an electrical separation between the simulated charging current and the simulated discharging current, which can be measured independently of each other. The current path conducting through the NPN transistor represents the discharging current of the first battery cell, and the current path conducting through the PNP transistor represents the charging current of the first battery cell.

[0025] A second cell voltage U having a second voltage regulator 7 and a second voltage measuring device 32 Z2 The closed loop control circuit for the first cell voltage U Z1 For the second cell voltage U Z2 Since the polarity of is reversed, the second cell voltage U of the NPN transistor and the PNP transistor Z2 are functionally swapped: the current path conducting through the NPN transistor represents the charging current of the second battery cell, and the current path conducting through the PNP transistor represents the discharging current of the second battery cell.

Claims

1. 1. A battery simulator comprising: the battery simulator includes a first electric circuit; the first electric circuit comprises a first cell voltage for simulating a voltage of a first battery cell dropping through a first subsection of the first electric circuit; The first electric circuit further includes control electronics for closed-loop control of the first cell voltage, the first cell voltage is connected to a local circuit ground; a second cell voltage for simulating a voltage of a second battery cell, which is controlled in a closed loop by the control electronics and falls through a second subsection of the first electric circuit, is connected to the same local circuit ground; the second cell voltage is connected in series with the first cell voltage such that the local circuit ground forms a pole of the first cell voltage and the second cell voltage; A battery simulator comprising:

2. The first electric circuit includes: a voltage source arranged to apply a supply voltage to the first electric circuit for operation of the electric components of the first electric circuit; a first voltage regulator powered by said supply voltage and arranged and configured to apply said first cell voltage to said first sub-interval and to control it in a closed loop to a first target value; an inverting converter powered by the supply voltage and connected in parallel with the first voltage regulator; a second voltage regulator powered by the output voltage of the inverting converter and arranged and configured to apply the second cell voltage to the second subsection and to control it in a closed loop to a second target value; Contains the control electronics are configured to set a first target value for the first voltage regulator such that the first target value is the same as a target setting for a voltage of the first battery cell; the control electronics is configured to set the second target value for the second voltage regulator such that the second target value is equal to a negative value of a target setting for the voltage of the second battery cell. The battery simulator according to claim 1.

3. the battery simulator includes a second electric circuit configured identically to the first electric circuit, providing a third cell voltage to simulate a voltage of a third battery cell, and providing a fourth cell voltage to simulate a voltage of a fourth battery cell; the second electric circuit is electrically connected to the first electric circuit such that the first cell voltage, the second cell voltage, the third cell voltage and the fourth cell voltage are connected in series.

3. The battery simulator according to claim 1 or 2.

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