Battery simulator with reduced demand for electrical components

Abstract

The invention relates to a battery simulator comprising a first circuit for providing a first battery cell voltage to simulate the voltage of the first battery cell and a second circuit for providing a second battery cell voltage to simulate the voltage of the second battery cell. The first cell voltage is placed on a local circuit ground line, and the second cell voltage is placed on the same local circuit ground line and connected in series with the first cell voltage such that the local circuit ground line forms a pole of the first cell voltage and the second cell voltage. The control electronics are designed to regulate the first cell voltage and the second cell voltage. Elements are saved by controlling two cell voltages by a unique control electronics.

Description

Technical Field

[0001] A battery simulator is a development system that is used in the prior art to test the performance of technical systems intended to interact with batteries. The technical system may be, for example, a battery management system that controls the charging and discharging process of battery cells, an electric motor of an electric vehicle powered by a battery, or a charging station. Background Art

[0002] The battery comprises a plurality of battery cells connected in series. Each battery cell is a galvanic cell or a galvanic cell which generates an individual cell voltage, so that the sum of all cell voltages forms the output voltage of the battery. Accordingly, battery simulators known from the prior art provide a plurality of simulated cell voltages which are connected in series and can be adjusted individually and also include a computer model which simulates the electrical properties of the galvanic cell for each simulated cell voltage in order to calculate the target setting for the respective cell voltage.

[0003] Figure 1 The diagram shows in simplified form the structure of a single simulated battery cell in a battery simulator according to the prior art of the applicant's product portfolio. A DC voltage converter provides the supply voltage for operating the electrical components, and a voltage regulator applies a simulated cell voltage to a subsection of the underlying circuit provided for it and regulates this simulated cell voltage to a target value set by the control electronics. The control electronics also include measurement technology, digital isolators, a microcontroller and an auxiliary voltage supply. As described above, a typical battery simulator is designed to simulate a large number of battery cells, so Figure 1 All individual components of the circuit shown in are also installed in corresponding quantities. Overall, this results in a high demand for electrical components, which leads to high prices and large space requirements for battery simulators. Summary of the invention

[0004] Against this background, it is an object of the present invention to reduce the requirement for electrical components for constructing a battery simulator.

[0005] In order to achieve this object, a battery simulator is proposed, which comprises a first circuit, a first cell voltage for simulating the voltage of a first battery cell is present on a first subsection of the circuit, and the circuit further comprises control electronics for regulating the first cell voltage.

[0006] The first cell voltage is placed on the local circuit ground. A second cell voltage simulating the voltage of a second battery cell is placed on a second subsection of the first circuit. The second cell voltage is also regulated by the control electronics and placed on the same local circuit ground as the first cell voltage. The second cell voltage is connected in series with the first cell voltage so that the local circuit ground forms one pole of the first cell voltage and the second cell voltage.

[0007] The local circuit ground forms a well-defined common zero potential for the two simulated cell voltages (the first cell voltage and the second cell voltage). The local circuit ground can be understood as a ground according to the technical terminology known from electrical engineering, but this ground is not a global ground of the battery simulator, but is implemented locally within the first circuit for the purpose of serving - in particular specifically - as a common zero potential for the first cell voltage and for the second cell voltage.

[0008] As mentioned above and as Figure 1 As shown, the circuits known in the prior art for simulating battery cells can simulate a single battery cell. In contrast, the first circuit according to the invention can simulate two battery cells and only slightly higher additional expenditure on electrical components for applying the second cell voltage is required to simulate the second battery cell. The two cell voltages share the electrical components of the control electronics and the voltage source for supplying the voltage. Overall, the battery simulator according to the invention therefore results in a significantly more efficient use of the electrical components. In a battery simulator that simulates a plurality of battery cells with the aid of a plurality of circuits according to the invention, the requirements for control electronics and local voltage supply devices are halved compared to the prior art.

[0009] The first circuit advantageously comprises a separate local voltage source, in particular a DC voltage converter, which is provided for applying a supply voltage for operating the electrical components of the first circuit to the first circuit. Furthermore, the first circuit advantageously comprises a first voltage regulator fed by the supply voltage, the first voltage regulator being provided and designed for applying a first cell voltage to the first subsection and regulating it to a first target value, and a second voltage regulator being provided and designed for applying a second cell voltage to the second subsection and regulating it to a second target value.

[0010] Since both the first cell voltage and the second cell voltage are applied to the local circuit ground, it makes sense for reasons of symmetry to invert one of the two cell voltages. Thus, for example, if the first cell voltage, which is defined as positive, is oriented in the direction of the local circuit ground, the second cell voltage, which is defined as positive, should be oriented away from the local circuit ground. For this purpose, the first circuit advantageously comprises an inverter connected in parallel with a first voltage regulator, which is fed by the supply voltage, and the second voltage regulator is fed by the output voltage of the inverter. The control electronics are designed to set a first target value for the first voltage regulator, such that the first target value is equal to 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 equal to the negative value of the target setting for the voltage of the second battery cell. The two target settings can be set, for example, by the above-mentioned computer model for simulating the electrical properties of a plurality of galvanic cells.

[0011] In order to be able to simulate more than just two battery cells, the battery simulator preferably comprises at least a second circuit in addition to the first circuit, which is designed identically to the first circuit and provides a third cell voltage for simulating the voltage of a third battery cell and a fourth cell voltage for simulating the voltage of a fourth battery cell in the same manner as described above. The second circuit is electrically connected to the first circuit so that the first cell voltage, the second cell voltage, the third cell voltage and the fourth cell voltage are connected in series in order to jointly simulate four battery cells connected in series. In the same way, the battery simulator can include, in principle, any number of circuits, which are all designed identically to the first circuit and are electrically connected to one another in such a way that all cell voltages simulated by the plurality of circuits are connected in series in order to simulate a plurality of battery cells connected in series of a battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is described in detail below with the help of the accompanying drawings. The accompanying drawings are as follows:

[0013] Figure 1 A circuit known from the prior art for simulating a single battery cell in a battery simulator is shown as a simplified block diagram;

[0014] Figure 2 A circuit for simulating two battery cells in a battery simulator according to the present invention is shown as a simplified block diagram; and

[0015] Figure 3 Show Figure 2 Detailed circuit diagram of the circuit shown in . DETAILED DESCRIPTION

[0016] Figure 1The diagram of FIG. 1 illustrates in block diagram form a circuit known from the prior art for simulating a first battery cell in a battery simulator. A DC voltage converter fed by a global voltage supply 2 of the battery simulator provides a supply voltage as a voltage source 4 for a first voltage regulator 6. The first voltage regulator 6 is arranged and designed to convert the first cell voltage U Z1 is applied to the first subsection 10 of the circuit. The microcontroller 8 uses the digital-to-analog converter 12 to set the first voltage regulator 6 for the first cell voltage U Z1 The first target value of the first cell voltage U Z1 The microcontroller communicates with a computer model implemented outside the circuit through the digital isolator 16 for simulating the electrical characteristics of a plurality of galvanic cell cells of the battery, and obtains the voltage U Z1 and transmits the target setting as a target value to the first voltage regulator 6 .

[0017] The differential amplifier 20 is provided to measure the current intensity of the current flowing through the first subsection 10 and to transmit the measured current intensity to the microcontroller 8 by means of the analog-to-digital converter 18. The microcontroller 8 transmits the actual value of the current intensity via the digital isolator 16 to the battery simulator.

[0018] Therefore, the circuit comprises a plurality of electrical components which together form a circuit for regulating the first cell voltage U Z1 and for measuring the voltage U Z1 The control electronics 22 also includes a digital isolator 16 , a microcontroller 8 , a digital-to-analog converter 12 , an analog-to-digital converter 18 , a differential amplifier 20 and an auxiliary voltage supply 14 for providing the electrical components of the control electronics 22 with operating voltages.

[0019] Figure 2 The diagram shows a method for simulating a first cell voltage U according to an exemplary embodiment of the present invention. Z1 and the second cell voltage U Z2 The following describes only the circuit Figure 1 The difference in the circuit shown in .

[0020] The inverter 24 fed by the voltage supply device 4 is connected in parallel with the first voltage regulator 6, inverts the voltage provided by the voltage supply device 4 and feeds the inverted voltage to the second voltage regulator 7. The second voltage regulator 7 is provided and designed to convert the second cell voltage U Z2 is applied to the second subsection 11 of the circuit. The microcontroller obtains the voltage for the second cell U from the computer model in a manner similar to that described above. Z2The second target setting and based on the target setting will be used for the second cell voltage U Z2 The second target value of is transmitted to the second voltage regulator, but the control electronics 22 is designed to invert the second target value relative to the target setting from the computer model. The second voltage regulator thus obtains a second cell voltage U Z2 The negative value of is used as the second target value, and the computer model sets the second target value as the second target setting.

[0021] The first monomer voltage U Z1 and the second cell voltage U Z2 are connected to a common local circuit ground 23, which thus forms the ground for the first cell voltage U Z1 and the second cell voltage U Z2 By reversing the voltage applied to the second voltage regulator 7 and the second target value by the inverter 24, the second cell voltage U defined as positive is achieved. Z2 The first cell voltage U is defined as being positive and oriented away from the local circuit ground line 23. Z1 Then it is oriented toward the guide circuit ground line 23 .

[0022] The differential amplifier 20 is provided and designed to additionally measure the current intensity of the current flowing through the second subsection 11 and to transmit the measured current intensity to the microcontroller 8 in a manner similar to that described above for transmission to the battery simulator.

[0023] It is easy to see in this figure that in order to provide the second cell voltage U Z2 Only minor additional expenditure on electrical components is required. The additional expenditure is essentially limited to the inverter 24, the second voltage regulator 7 and a further measuring resistor. In the battery simulator, a number of circuits (such as Figure 2 ) can be interconnected with one another in such a way that all the cell voltages simulated by the multiple circuits are connected in series, thereby forming a long series circuit of simulated cell voltages that can be adjusted 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, every two cell voltages share one control electronics 22 and one voltage source 4. This results in a significant saving of electrical components in a battery simulator designed to simulate a plurality of battery cells.

[0024] Figure 3 The diagram of FIG. 1 shows a more detailed circuit diagram of the first circuit without the control electronics 22. The first voltage measuring device 30 designed as a differential amplifier measures the first cell voltage U 2 which is present in the first subsection. Z1The first voltage regulator 6 includes an error amplifier, and the first cell voltage U output by the first voltage measuring device 30 is Z1 The actual value of the first cell voltage U is applied to the first input of the error amplifier and output by the digital-to-analog converter 12 Z1 The target value of is applied to the second input of the error amplifier. The output voltage of the differential amplifier is applied as a base voltage to one of the two transistors, one of which is configured as an NPN transistor and the other as a PNP transistor. The emitter-collector voltage of each of the two transistors is applied by a voltage source 4.

[0025] Once the microcontroller 8 changes the Z1 The target value is Z1 A difference will occur between the target value and the actual value, which causes the error amplifier to adjust the base voltage applied to the NPN transistor and the base voltage applied to the PNP transistor. The error amplifier is constructed to Z1 When the target value is higher than the actual value, the base voltage is increased and when U Z1 When the target value is lower than the actual value, the base voltage is reduced. Z1 The resistance of the NPN transistor increases and the resistance of the PNP transistor decreases, or vice versa.

[0026] Since only one of the two transistors, the NPN transistor or the PNP transistor, is always conducting, there is electrical isolation between the analog charging current and the analog discharging current, so that the two currents can be measured independently of each other. The current path flowing through the NPN transistor forms the discharging current of the first battery cell, and the current path flowing through the PNP transistor forms the charging current of the first battery cell.

[0027] The second cell voltage U having a second voltage regulator 7 and a second voltage meter 32 Z2 The regulating circuit is constructed similarly, but due to the second cell voltage U Z2 The polarity of the first monomer voltage U Z1 The polarities of the NPN transistor and the PNP transistor are opposite, and the functions of the NPN transistor and the PNP transistor are interchanged. The current path flowing through the NPN transistor forms the charging current of the second battery cell, and the current path flowing through the PNP transistor forms the discharging current of the second battery cell.

Claims

1. A battery simulator comprising a first circuit having a first cell voltage for simulating the voltage of a first battery cell falling on a first subsection of the first circuit and control electronics for regulating the first cell voltage, characterized in that The first cell voltage is placed on the local circuit ground; A second cell voltage regulated by the control electronics and placed on a second subsection of the first circuit to simulate a voltage of a second battery cell is placed on the same local circuit ground; and The second cell voltage is connected in series with the first cell voltage so that the local circuit ground line forms one pole of the first cell voltage and the second cell voltage.

2. The battery simulator according to claim 1, wherein The first circuit comprises: a voltage source configured to apply a supply voltage for operating electrical components of the first electrical circuit to the first electrical circuit; a first voltage regulator fed by the supply voltage, which is arranged and designed to apply a first cell voltage to the first subsection and to regulate it to a first target value; a flyback converter fed by the supply voltage, the flyback converter being connected in parallel with the first voltage regulator; a second voltage regulator fed by the output voltage of the inverter, the second voltage regulator being arranged and designed to apply a second cell voltage to the second subsection and to regulate it to a second target value; The control electronics are designed to set a first target value for the first voltage regulator such that the first target value is equal to a 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 equal to the negative value of the target setting for the voltage of the second battery cell.

3. The battery simulator according to claim 1 or 2 comprises a second circuit designed identically to the first circuit to provide a third cell voltage for simulating the voltage of a third battery cell and a fourth cell voltage for simulating the voltage of a fourth battery cell, wherein the second circuit is electrically connected to the first circuit so that the first cell voltage, the second cell voltage, the third cell voltage and the fourth cell voltage are connected in series.

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