Temperature simulation device and method and hardware-in-loop test device for energy storage system

Abstract

The invention provides a temperature simulation device and method and a hardware-in-the-loop testing device for an energy storage system, and relates to the technical field of battery management system testing. The device comprises an analog quantity output module used for receiving a target voltage and outputting a corresponding analog voltage signal; the first end of the first divider resistor is connected with the output end of the analog quantity output module, and the second end is grounded; the two ends of the first divider resistor are also used for connecting a signal acquisition end of an analog front end in a temperature acquisition circuit; the control module is electrically connected with the analog quantity output module and used for calculating target voltage according to the target temperature and sending the target voltage to the analog quantity output module; wherein the target voltage is calculated based on a predetermined corresponding relation between the temperature and the resistance value of the NTC resistor and a corresponding relation between different resistance values and the divided voltage. According to the invention, the voltage signals of the real NTC resistor at different temperatures can be accurately simulated, and the temperature simulation precision and the hardware-in-the-loop test accuracy are improved.

Description

Technical Field

[0001] This application relates to the field of battery management system testing technology, and in particular to a temperature simulation device, method, and hardware-in-the-loop testing device for energy storage systems. Background Technology

[0002] The main function of a Battery Management System (BMS) is to monitor, control, and protect the battery's state. Among these functions, monitoring the battery cell temperature directly impacts battery safety. Current BMSs monitor cell temperature through temperature acquisition circuits. The core principle is as follows: a negative temperature coefficient (NTC) thermistor is placed in contact with the battery cell, converting the cell temperature into an NTC resistance value. This resistance change is then converted into a voltage signal suitable for analog-to-digital (A / D) sampling via a voltage divider. An analog front-end (AFE) acquires this voltage signal through analog-to-digital conversion, and finally, the cell temperature is deduced from this voltage signal, thus achieving cell temperature monitoring.

[0003] In the testing scenario of Battery Management System (BMS), the hardware-in-the-loop (HIL) test for simulating cell temperature is a test to verify whether the temperature acquisition and control functions of the BMS are normal. Its core requirement is to simulate the resistance change of the NTC resistor caused by cell temperature, that is, to use a virtual temperature signal to replace the actual cell temperature in order to verify whether the temperature acquisition circuit in the BMS is functioning properly.

[0004] However, a battery module contains a large number of cells. Each cell requires an NTC thermistor, and a corresponding channel is set up to collect the voltage signal across the NTC resistor, thereby deriving the temperature of each cell. In actual testing scenarios, it is necessary to collect the voltage signals across the NTC resistors at different temperatures across multiple channels. Therefore, it is necessary to specifically change the ambient temperature of each NTC resistor to simulate the different temperatures of each cell. However, the actual testing conditions cannot provide an accurate temperature environment for each NTC resistor, resulting in low accuracy of cell temperature simulation, which in turn leads to low accuracy of the final hardware-in-the-loop (HIL) test. Summary of the Invention

[0005] This application provides a temperature simulation device, method, and hardware-in-the-loop testing device for energy storage systems to solve the problem that in the prior art, actual test conditions cannot provide an accurate temperature environment for each NTC resistor, resulting in low accuracy of cell temperature simulation and consequently low accuracy of the final hardware-in-the-loop (HIL) test.

[0006] In a first aspect, embodiments of this application provide a temperature simulation device, comprising: The analog output module is used to receive the target voltage and output the corresponding analog voltage signal; The first voltage divider resistor has its first end connected to the output terminal of the analog output module and its second end grounded. The two ends of the first voltage divider resistor are also used to connect to the signal acquisition terminal of the analog front end in the temperature acquisition circuit; The control module, electrically connected to the analog output module, is used to calculate the target voltage based on the target temperature and send the target voltage to the analog output module. The target voltage is calculated based on a predetermined relationship between the temperature and resistance value of the NTC resistor and the relationship between different resistance values ​​and voltage dividers.

[0007] In one possible implementation, the temperature simulation device further includes: A protective element, connected in series between the analog output module and the first voltage divider resistor, is used to prevent the constant power supply in the temperature acquisition circuit from flowing backward into the analog output module.

[0008] In one possible implementation, the step of the control module calculating the target voltage based on the target temperature includes: Based on the target temperature, the equivalent resistance of the NTC resistor is calculated using a first formula; the first formula is used to express the relationship between the temperature and the resistance of the NTC resistor. The equivalent voltage divider voltage of the NTC resistor is calculated based on the equivalent resistance value, the voltage provided by the constant power supply in the temperature acquisition circuit, and the second formula. The current flowing through the protective element is calculated based on the equivalent voltage divider and the resistance value of the first voltage divider resistor. Calculate the voltage drop of the protective element based on the relationship between the current and voltage drop of the protective element; The sum of the equivalent voltage divider and the voltage drop of the protective element is taken as the target voltage.

[0009] In one possible implementation, the first formula is: ; The second formula is: ; in, , and The resistivity of the NTC resistor is given by T, where T represents temperature. This indicates the resistance value of the NTC resistor. This indicates the voltage supplied by the constant power supply in the temperature acquisition circuit. This indicates the resistance value of the second voltage-dividing resistor connected in series with the first voltage-dividing resistor in the temperature acquisition circuit. This represents the equivalent voltage divider voltage of the NTC resistor at temperature T; The relationship between the current and voltage drop of the protective element is expressed by the third and fourth formulas, wherein the third formula is: ; The fourth formula is: ; in, , , and The coefficient of the resistance value of the protective component. This indicates that the voltage across the first voltage divider resistor is The current flowing through the protective element corresponds to the current at that time. Indicates the current of the protective element is The corresponding resistance value at that time This indicates the voltage drop across the protective component.

[0010] In one possible implementation, the analog output module is an analog circuit board; The analog signal board includes N mutually isolated output channels, and the output terminal of each output channel is connected to the first terminal of a first voltage divider resistor through a protection element; N is a positive integer greater than 0. The second terminals of all the first voltage divider resistors are connected to a common ground; The first end of each first voltage divider resistor is also used to connect to a signal acquisition terminal in the analog front end.

[0011] In one possible implementation, the protective element is a diode; The anode of the diode is connected to the output terminal of the analog output module, and the cathode is connected to the first terminal of the first voltage divider resistor.

[0012] Secondly, embodiments of this application provide a temperature simulation method, including: Based on the preset target temperature, the temperature-resistance relationship of the NTC resistor, and the relationship between different resistance values ​​and voltage dividers, the target voltage that the analog output module needs to output is calculated. The target voltage is sent to the analog output module so that the analog output module receives the target voltage and outputs a corresponding analog voltage signal; The analog voltage signal passes through the first voltage divider resistor, generating a voltage divider signal equivalent to that of the NTC resistor across the first voltage divider resistor; The voltage divider signal is transmitted to the analog front end in the temperature acquisition circuit to simulate the voltage divider voltage of the NTC resistor corresponding to the target temperature.

[0013] In one possible implementation, the step of calculating the target voltage that the analog output module needs to output, based on the pre-set target temperature, the temperature-resistance relationship of the NTC resistor, and the relationship between different resistance values ​​and voltage dividers, includes: The equivalent resistance of the NTC resistor is calculated using the first formula; the first formula is used to express the relationship between the temperature and the resistance of the NTC resistor. The equivalent voltage divider voltage of the NTC resistor is calculated based on the equivalent resistance value, the voltage provided by the constant power supply in the temperature acquisition circuit, and the second formula. The current flowing through the protection element is calculated based on the equivalent voltage divider and the resistance value of the first voltage divider resistor. Calculate the voltage drop of the protective element based on the relationship between the current and voltage drop of the protective element; The sum of the equivalent voltage divider and the voltage drop of the protective element is taken as the target voltage.

[0014] In one possible implementation, calculating the voltage drop of the protection element based on the correspondence between the current and voltage drop of the protection element includes: The resistance of the protective element is calculated based on the current flowing through it and the third formula; the third formula is used to express the correspondence between the current and the resistance of the protective element. The voltage drop of the protective element is calculated based on the resistance value of the protective element and the fourth formula.

[0015] In one possible implementation, the first formula is: ; The second formula is: ; in, , and The resistivity of the NTC resistor is given by T, where T represents temperature. This indicates the resistance value of the NTC resistor. This indicates the voltage supplied by the constant power supply in the temperature acquisition circuit. This indicates the resistance value of the second voltage-dividing resistor connected in series with the first voltage-dividing resistor in the temperature acquisition circuit. This represents the equivalent voltage divider voltage of the NTC resistor at temperature T; The third formula is: ; The fourth formula is: ; in, , , and The coefficient of the resistance value of the protective component. This indicates that the voltage across the first voltage divider resistor is The current flowing through the protective element corresponds to the current at that time. Indicates the current of the protective element is The corresponding resistance value at that time This indicates the voltage drop across the protective component.

[0016] Thirdly, embodiments of this application provide a hardware-in-the-loop testing device for an energy storage system, comprising: a temperature simulation device as described in any of the first aspects of this application and a battery management system under test; the battery management system under test is used to perform battery management on the energy storage batteries of the energy storage system.

[0017] In this embodiment, the signal of the NTC resistor is simulated by a combination of a control module, an analog output module, and a first voltage divider resistor. The first end of the first voltage divider resistor is connected to the output end of the analog output module, and the second end is grounded. The control module is electrically connected to the analog output module. The control module can automatically calculate the target voltage corresponding to the target temperature based on the temperature-resistance-voltage divider relationship of the NTC resistor. Then, the analog output module converts the target voltage into an analog voltage signal and directly transmits the analog voltage signal to the first voltage divider resistor. A voltage divider signal equivalent to that of the NTC resistor is formed across the first voltage divider resistor. The voltage signal across the first voltage divider resistor is transmitted to the analog front end in the temperature acquisition circuit, thereby ensuring that the voltage signal across the first voltage divider resistor acquired by the temperature acquisition circuit in the BMS is the same as the voltage divider signal of the real NTC resistor at the target temperature, which greatly improves the accuracy of cell temperature simulation. Furthermore, it does not rely on the real cell and the real NTC resistor attached to the cell, avoiding the risk of difficulty in controlling the real ambient temperature. It can adapt to the hardware-in-the-loop (HIL) test requirements for cell temperature simulation, thereby ensuring the accuracy of the BMS test results.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the temperature acquisition circuit provided in one embodiment of this application; Figure 2 This is a schematic diagram of the structure of a temperature simulation device provided in an embodiment of this application; Figure 3 This is a schematic diagram of the hardware-in-the-loop testing device for a BMS provided in one embodiment of this application; Figure 4 This is a schematic diagram of the hardware-in-the-loop testing device for a BMS provided in another embodiment of this application; Figure 5 This is a schematic diagram of the hardware-in-the-loop testing device for a BMS provided in another embodiment of this application; Figure 6 This is a schematic diagram of the structure of a temperature simulation device provided in another embodiment of this application; Figure 7 This is a temperature-resistance characteristic curve of an NTC resistor provided in one embodiment of this application; Figure 8 This is a temperature-voltage characteristic curve of an NTC resistor provided in one embodiment of this application; Figure 9 This is a characteristic curve of diode voltage division provided in an embodiment of this application; Figure 10 This is a characteristic curve of diode current-resistance provided in one embodiment of this application; Figure 11 This is a curve showing the correspondence between temperature and board output voltage and temperature and equivalent voltage divider voltage of NTC resistor provided in one embodiment of this application; Figure 12 This is a schematic flowchart of a temperature simulation method provided in an embodiment of this application; Figure 13 This is a schematic diagram of the structure of a control device provided in an embodiment of this application. Detailed Implementation

[0021] The present application will be described more clearly below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the function of the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0022] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0023] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] In the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0026] Furthermore, the term "multiple" mentioned in the embodiments of this application should be interpreted as two or more.

[0027] The main function of a Battery Management System (BMS) is to monitor, control, and protect the battery's condition. Among these functions, monitoring the battery cell temperature directly impacts battery safety. Current BMSs acquire cell temperature through temperature acquisition circuits and issue alert signals when the cell temperature is too high. For example... Figure 1 As shown, the temperature acquisition circuit includes voltage divider resistors R. CC A 5V constant power supply and an analog front-end (AFE), which includes an analog-to-digital converter module; voltage divider resistors R CCThe first terminal is connected to a 5V constant power supply, and the second terminal is connected to the first port (P port) of the signal acquisition terminal of the analog front-end AFE. The second port (Q port) of the signal acquisition terminal of the analog front-end AFE is grounded. The signal acquisition terminal of the analog front-end AFE is used to connect to the NTC thermistor R. NTC At both ends, the NTC thermistor is attached to the battery cell. As the battery cell temperature changes, the NTC resistance changes synchronously (the higher the temperature, the lower the NTC resistance), thus converting the battery cell temperature into NTC resistance. This is due to the voltage divider resistor R... CC and NTC resistor R NTC This forms a voltage divider circuit, sharing the 5V voltage, through the NTC resistor and the voltage divider resistor R. CC The "voltage divider" method converts the resistance change into a voltage difference across the NTC resistor (i.e., the conversion from temperature to resistance to voltage). This voltage difference is adapted to the 0~5V sampling range requirement of the analog front-end AFE. The voltage difference signal across the NTC resistor is the core acquisition target of the analog front-end AFE. The analog front-end AFE converts the acquired voltage signal into a digital signal through analog-to-digital conversion (AD conversion) and transmits it to the Battery Management Unit (BMU) in the Battery Management System (BMS). The BMU uses the digital signal to infer the cell temperature, thereby realizing cell temperature monitoring. The whole process forms a signal chain of "cell temperature → NTC resistance → voltage difference across the NTC resistor → AFE acquisition → BMU inference".

[0028] In the testing scenario of Battery Management System (BMS), hardware-in-the-loop (HIL) testing for cell temperature simulation is a test to verify whether the temperature acquisition and control functions of the BMS are normal. Its core requirement is to simulate the resistance change of the NTC resistor caused by cell temperature. That is, to use a virtual temperature signal to replace the actual cell temperature, and then to inversely deduce the cell temperature based on the voltage signal across the NTC resistor acquired by the simulation front-end AFE. The inversely deduced cell temperature is compared with the simulated temperature. If the inversely deduced cell temperature is equal to the simulated temperature, it proves that the temperature acquisition circuit is functioning normally; otherwise, it proves that the temperature acquisition circuit is malfunctioning.

[0029] However, a battery module contains a large number of cells. Each cell requires an NTC thermistor, and a corresponding channel is set up to collect the voltage signal across the NTC resistor, thus deriving the temperature of each cell. In actual testing scenarios, it's necessary to collect voltage signals across multiple NTC resistors at different temperatures. Therefore, the ambient temperature of each NTC resistor needs to be adjusted to simulate the temperature of each cell. However, actual testing conditions cannot provide an accurate temperature environment for each NTC resistor, resulting in low cell temperature simulation accuracy and consequently low accuracy in the final hardware-in-the-loop (HIL) test. If precision adjustable resistors are used instead of NTC resistors in HIL testing, manually adjusting the resistance value of these resistors to simulate the resistance of NTC resistors at different temperatures increases testing costs. Furthermore, manually adjusting the resistance value of each precision adjustable resistor is not only cumbersome but also difficult to control in terms of precision, affecting the accuracy of the BMS test results.

[0030] To address the aforementioned technical problems, this application proposes the following technical concept: A temperature simulation device is constructed using a first voltage-dividing resistor, an analog output module, and a control module. The first voltage-dividing resistor replaces the actual NTC resistor and is connected to the two ports of the signal acquisition terminal of the analog front-end AFE in the temperature acquisition circuit (e.g., ...). Figure 1 Between the P and Q ports of the NTC resistor, an adjustable DC source is formed by an analog output module and a control module. The output of the analog output module is connected to the first end of the first voltage divider resistor, and the second end of the first voltage divider resistor is grounded. The control module automatically calculates the target voltage corresponding to the target temperature based on the temperature-resistance-voltage divider relationship of the NTC resistor. Then, the analog output module converts the target voltage into an analog voltage signal. The analog voltage signal is directly transmitted to the first voltage divider resistor, forming a voltage divider signal equivalent to that of the NTC resistor across the first voltage divider resistor, thereby ensuring that the temperature acquisition circuit in the BMS acquires the first voltage. The voltage signal across the voltage divider resistor is the same as the voltage divider voltage signal of the real NTC resistor at the target temperature, which greatly improves the accuracy of cell temperature simulation. Moreover, it does not rely on real cells and real NTC resistors attached to the cells, avoiding the risk of difficulty in controlling the real ambient temperature. It can adapt to the hardware-in-the-loop (HIL) test requirements for cell temperature simulation, thus ensuring the accuracy of BMS test results. Furthermore, by simulating NTC signals through control modules, analog output modules, and ordinary voltage divider resistors, there is no need to use precision adjustable resistors, which not only significantly reduces hardware costs but also supports automated program control and improves test efficiency.

[0031] Figure 2 This is a schematic diagram of the structure of a temperature simulation device provided in an embodiment of this application.

[0032] like Figure 2As shown, the temperature simulation device provided in this embodiment includes: an analog output module for receiving a target voltage and outputting a corresponding analog voltage signal; a first voltage divider resistor (R1), with its first end connected to the output terminal of the analog output module and its second end grounded (GND); the two ends of the first voltage divider resistor R1 are also used to connect to the signal acquisition terminal of the analog front-end in the temperature acquisition circuit (such as...). Figure 1 The control module (P and Q terminals) is electrically connected to the analog output module and is used to calculate the target voltage based on the target temperature and send the target voltage to the analog output module; wherein, the target voltage is calculated based on a predetermined correspondence between the temperature and resistance value of the NTC resistor and the correspondence between different resistance values ​​and voltage dividers.

[0033] In the test scenario, the two ends of the first voltage divider resistor R1 of the temperature simulation device provided in this embodiment are connected to the signal acquisition terminal of the analog front-end AFE in the temperature acquisition circuit, forming a hardware-in-the-loop test device for the BMS, such as... Figure 3 As shown.

[0034] It should be noted that the hardware-in-the-loop testing device in this embodiment is used to test the battery management system under test in the energy storage system. The energy storage system includes multiple battery clusters, each of which is formed by connecting multiple energy storage battery packs. The battery management system under test is used to manage the entire energy storage system, or the battery clusters, or each energy storage battery, in order to monitor, control, and protect the working status of each energy storage battery.

[0035] In this embodiment, the temperature simulation device, consisting of a first voltage divider resistor R1, an analog output module, and a control module, is used to simulate the temperature of a real NTC resistor. Figure 1 In the middle and voltage divider resistor R CC The voltage divider circuit formed by the voltage divider circuit has real voltage divider signals corresponding to different cell temperatures (i.e., simulating the link of "temperature → NTC resistance value → voltage divider of NTC resistor" in the above signal chain, replacing the real TNC resistor to realize temperature simulation), so that the voltage divider signal corresponding to the first voltage divider resistor R1 at the target temperature is equivalent to the voltage divider signal of the real NTC resistor at the same cell temperature.

[0036] Specifically, the relationship between temperature and resistance of an NTC resistor can be obtained by fitting the temperature-resistance characteristic of the NTC resistor. The relationship between different NTC resistance values ​​and voltage divider voltages can be obtained by... Figure 1 The voltage (5V) provided by the constant power supply and the voltage divider resistor R CCThe voltage divider principle of R1 is used to obtain the voltage. After determining the temperature-resistance correspondence and the resistance-voltage divider correspondence of the NTC resistor, the set target temperature is input to the controller. The controller substitutes the target temperature into the calculation to obtain the target voltage. Since the calculated target voltage is a digital signal, it needs to be converted into an analog voltage signal through the analog output module and directly output to the first voltage divider resistor R1. An equivalent voltage divider signal of the NTC resistor at the target temperature is formed across R1, realizing high-precision voltage signal simulation of the NTC resistor at the target temperature.

[0037] In this embodiment, a temperature simulation device is formed by using a first voltage divider resistor, an analog output module, and a control module. The first voltage divider resistor replaces the actual NTC resistor and is connected to the two ports of the signal acquisition terminal of the analog front-end AFE in the temperature acquisition circuit (e.g., ...). Figure 1 Between the P and Q ports (in the circuit), an adjustable DC source is formed by an analog output module and a control module. Only a target temperature value needs to be input, and the system can automatically calculate and output the corresponding analog voltage signal. This analog voltage signal is directly transmitted to the first voltage divider resistor, forming a voltage divider signal equivalent to that of an NTC resistor across it. This ensures that the voltage signal acquired by the temperature acquisition circuit in the BMS is the same as the voltage divider signal of the actual NTC resistor at the target temperature, greatly improving the accuracy of cell temperature simulation. Furthermore, it eliminates the need for actual cells and the actual NTC resistor attached to them, avoiding the risk of uncontrollable ambient temperatures. This adapts to the hardware-in-the-loop (HIL) testing requirements for cell temperature simulation, ensuring the accuracy of BMS test results. Moreover, by simulating the NTC signal using the control module, analog output module, and ordinary voltage divider resistor, the use of a precision adjustable resistor is eliminated, significantly reducing hardware costs and supporting automated program control, thus improving testing efficiency.

[0038] It should be noted that the constant power supply for the temperature acquisition circuit provides a voltage of 5V. The resistance of the NTC resistor is inversely proportional to the temperature; the higher the temperature, the lower the resistance. Figure 7 The temperature-resistance characteristic curve of the NTC resistor shown is illustrated (horizontal axis: temperature, vertical axis: resistance (kΩ)). The minimum resistance of the NTC is 500 kΩ (corresponding to 127℃), and the maximum resistance is 208 kΩ (corresponding to -42℃). Figure 1 In the middle, it consists of an NTC resistor and a voltage divider resistor R. CC The voltage divider circuit consists of components that share the 5V voltage. To ensure the voltage range across the NTC resistor, the voltage divider resistor R is set. CCThe resistance is 30kΩ. Therefore, based on the voltage divider principle, the voltage range of the NTC resistor can be calculated to be 0.084V (corresponding to 127℃, NTC resistance 500Ω) to 4.37V (corresponding to -42℃, NTC resistance 208kΩ). Therefore, it can be determined that the voltage range simulated by the temperature simulation device in this embodiment is typically 0~4.5V.

[0039] In one possible implementation, the analog output module can be an analog board that supports ±10V voltage adjustment, fully covering the voltage range of 0~4.5V.

[0040] In one possible implementation, the value of the first voltage divider resistor can be determined based on the NTC resistor and the driving capability of the analog signal board. Since the first voltage divider resistor is used to replace the actual NTC resistor between the two ports of the signal acquisition terminal of the simulator's front-end AFE, and given that the minimum resistance of an NTC resistor is 500Ω, the resistance of the first voltage divider resistor R1 needs to be less than 500Ω to ensure the voltage across it is within the range of 0~4.5V. Furthermore, since the driving capability of the analog signal board is 20mA, according to the board's driving capability R=U / I=5V / 20mA=250Ω, the resistance of R1 needs to be greater than or equal to 250Ω. That is, the resistance of the first voltage divider resistor R1 can be selected within the range of 250~500Ω. For example, a 330Ω voltage divider resistor can be selected, which fits the resistance range, matches the board's driving capability, ensures stable circuit current, and avoids overload.

[0041] Figure 4 This is a schematic diagram of the hardware-in-the-loop testing device for a BMS provided in another embodiment of this application.

[0042] like Figure 4 As shown, the hardware-in-the-loop testing device includes the temperature simulation device provided in this embodiment. The temperature simulation device also includes a protection element connected in series between the analog output module and the first voltage divider resistor.

[0043] In one possible implementation, such as Figure 3As shown, the hardware loop-in-the-loop test device, composed of the temperature acquisition circuit and the temperature simulation device provided in this embodiment, includes two DC power supplies. The constant power supply provides 5V, while the voltage output of the analog output module typically ranges from 0 to 4.5V. Therefore, the 5V constant power supply may cause reverse current to flow into the analog output module, forming a path from 5V power supply → analog output module → GND. This path is connected in parallel across the first voltage divider resistor R1, which can easily lead to voltage instability across R1. This results in insufficient accuracy of the analog voltage divider signal acquired by the analog front-end (AFE), leading to inaccurate test results. Therefore, this embodiment further adds a protective element connected in series between the analog output module and the first terminal of the first voltage divider resistor to prevent reverse current from flowing from the constant power supply in the temperature acquisition circuit into the analog output module.

[0044] In one possible implementation, such as Figure 5 As shown, the protective element can be a diode, with the anode of the diode connected to the output terminal of the analog output module and the cathode connected to the first terminal of the first voltage divider resistor.

[0045] Furthermore, the diode can be a Schottky diode.

[0046] In this embodiment, by adding a protective component (diode), it is possible to prevent the temperature acquisition circuit (such as the 5V power supply of the BMU) from reverse-flowing into the analog output module, ensuring the voltage across the first voltage divider resistor R1 is stable, thereby improving the accuracy of the voltage signal acquired by the analog front-end AFE and avoiding the problem of inaccurate test results caused by dual power supply conflict; it can also prevent the internal components of the analog output module from being damaged due to overvoltage, thus improving circuit stability.

[0047] It should be noted that the target voltage provided by the analog signal transceiver board is transmitted to the first voltage divider resistor R1 via a diode. Since the target voltage changes according to the target temperature, the current flowing through the diode and the first voltage divider resistor R1 also changes accordingly. The diode's resistance changes with the current, and the diode voltage divider results in a lower actual voltage across R1, which cannot be fully equivalent to the voltage divider voltage of the NTC resistor. This leads to inaccurate voltage signals acquired by the analog front-end (AFE), affecting the accuracy of the test results.

[0048] In actual testing scenarios, combined with Figure 5 When the voltage output by the analog input circuit board varies within the range of 0~5V, the corresponding diode voltage division is as follows: Figure 9 As shown, the horizontal axis represents the output voltage of the analog input board (V), and the vertical axis represents the corresponding diode voltage divider (V). Through... Figure 9The diode voltage divider curve shown indicates that when the analog input board's output voltage is low (0~2.7V), the diode voltage divider (diode voltage drop) exhibits a non-linear relationship. Since the analog input board's output voltage is typically in the range of 0~4.5V, the diode voltage divider is unstable most of the time, resulting in an unstable actual voltage distributed to the first voltage divider resistor R1. Therefore, when calculating the target output voltage of the analog input board, the diode voltage drop must be considered, ensuring that the voltage actually transmitted to the first voltage divider resistor R1 after the target output voltage is divided by the diode is equal to the equivalent voltage divider voltage of the NTC resistor. That is, at the target temperature, the target output voltage of the analog input board = the equivalent voltage divider voltage of the NTC resistor + the diode voltage drop. In one possible implementation, the step of the control module calculating the target voltage based on the target temperature includes: Step 1: Calculate the equivalent resistance of the NTC resistor using the first formula based on the target temperature; the first formula is used to express the correspondence between the temperature and the resistance of the NTC resistor.

[0049] In this step, the temperature versus resistance characteristic curve of the NTC resistor is as follows: Figure 7 As shown, the horizontal axis represents temperature (°C), and the vertical axis represents NTC resistance (kΩ). The corresponding first formula is: .

[0050] in, , , . , and The resistivity of the NTC resistor is given by T, where T represents temperature. This indicates the resistance value of the NTC resistor.

[0051] Step 2: Calculate the equivalent voltage divider voltage of the NTC resistor based on the equivalent resistance value, the voltage provided by the constant power supply in the temperature acquisition circuit, and the second formula.

[0052] The second formula is: .

[0053] This indicates the voltage (5V) provided by the constant power supply in the temperature acquisition circuit. This indicates the resistance value (30kΩ) of the second voltage divider resistor connected in series with the first voltage divider resistor in the temperature acquisition circuit. This represents the equivalent voltage divider voltage of the NTC resistor at temperature T.

[0054] In this step, after the target temperature is set, the controller can automatically substitute the target temperature into the first formula to obtain the equivalent resistance value of the NTC resistor, and then substitute the equivalent resistance value into the second formula to obtain the corresponding equivalent voltage divider voltage of the NTC resistor.

[0055] For example, by combining the first and second formulas, the equivalent voltage divider of the NTC resistor at different temperatures can be calculated, and the temperature-NTC voltage characteristic curve of the NTC resistor can be obtained by fitting the curve. Figure 8 As shown, the horizontal axis represents temperature, and the vertical axis represents NTC voltage (V).

[0056] Step 3: Calculate the current flowing through the protective element based on the equivalent voltage divider and the resistance value of the first voltage divider resistor.

[0057] In this step, when the voltage across the first voltage divider resistor R1 meets the NTC equivalent voltage divider voltage at the target temperature, the current flowing through the first voltage divider resistor R1 is calculated. This current is taken as the current flowing through the protection element (diode), i.e. .

[0058] Step 4: Calculate the voltage drop of the protective element based on the correspondence between the current and voltage drop of the protective element.

[0059] In this step, the relationship between the current and voltage drop of the protection element (diode) is expressed by the third and fourth formulas. The third formula represents the current-resistance relationship of the diode, and the corresponding characteristic curve is shown below. Figure 10 As shown, the horizontal axis represents the current (I) flowing through the diode, and the vertical axis represents the diode resistance (Ω). Figure 10 The diode current-resistance characteristic curve shown indicates that when the voltage across the diode is 0.4V below the forward voltage, the smaller the current, the larger the diode resistance. Based on the Shockley second-order body model, a third formula is obtained: .

[0060] in, , , , .

[0061] The fourth formula is: .

[0062] in, , , and The coefficient of the resistance value of the protective component. This indicates that the voltage across the first voltage divider resistor is The current flowing through the protective element corresponds to the current at that time. Indicates the current of the protective element is The corresponding resistance value at that time This indicates the voltage drop across the protective component.

[0063] It should be noted that the diode operating mode used in this application differs from that in traditional ordinary circuits. This application utilizes the conduction and cutoff characteristics of the diode under low-voltage conditions. Specifically, in traditional ordinary circuits, Schottky diodes are typically used under high-voltage conditions, where the diode's PN junction is in a saturated state, and the diode exhibits constant resistance. However, in this embodiment, since the board's output voltage is typically in the range of 0~4.5V, it is equivalent to using the Schottky diode under low-voltage conditions. Within the low-voltage range, the Schottky diode is in a small injection region under non-ideal conditions, and the diode exhibits non-linear resistive changes. Therefore, a mathematical model of the diode (as shown in the third formula above) is needed. Utilizing the diode's unidirectional conduction, a voltage is applied to the input terminal, and the voltage drop of the diode under non-ideal conditions is estimated using the input voltage, thereby obtaining the output voltage applied to the NTC resistor to simulate temperature changes.

[0064] Step 5: The sum of the equivalent voltage divider and the voltage drop of the protection element is taken as the target voltage.

[0065] In this step, the sum of the equivalent voltage divider and the corresponding diode voltage drop is taken as the target voltage (V) of the final output of the analog circuit board. B The fifth formula is: .

[0066] For example, when the target temperature is within the range of -100 to 200°C, the equivalent voltage divider of the NTC resistor corresponding to different target temperatures can be calculated by simultaneously applying the above formulas. The output voltage of the board at different target temperatures is then fitted to obtain the equivalent voltage divider voltage of the temperature-NTC resistor. The two curves, temperature and board output voltage, are as follows: Figure 11 As shown, the horizontal axis represents temperature (°C), and the vertical axis represents voltage (V). The blue curve represents the board's output voltage, and the red curve represents the equivalent voltage drop across the NTC resistors. At the same temperature, the difference between the two curves is the diode voltage drop. In actual testing, when the target temperature changes, ensure that the voltage across the first voltage divider resistor R1 always falls on the red curve.

[0067] In this embodiment, by combining the above five formulas, after setting the target temperature, the control module automatically calculates the target voltage that the analog signal board needs to output corresponding to the target temperature according to the above formulas, and converts the target voltage into an analog voltage signal; this analog voltage signal is first divided by a diode ( After that, it is transmitted to the first voltage divider resistor R1, and finally a voltage divider signal equivalent to that of the NTC resistor is formed across the first voltage divider resistor R1. The voltage signal across the first voltage divider resistor R1 acquired by the simulated front-end AFE is exactly the same as the voltage divider signal of the real NTC resistor at the target temperature, realizing the accurate simulation of "temperature → NTC resistance value → voltage divider of NTC resistor". Then, the simulated front-end AFE converts the voltage divider signal into a digital signal through the AD module, so as to infer the temperature from the digital signal, thereby replacing the real TNC resistor to achieve a high-precision temperature model and improving the accuracy of BMS test results.

[0068] In one possible implementation, the analog circuit board includes N mutually isolated output channels, each output channel's output terminal being connected to the first terminal of a first voltage divider resistor via a protection element; N is a positive integer greater than 0; the second terminals of all the first voltage divider resistors are connected to a common ground; the first terminal of each first voltage divider resistor is also used to connect to a signal acquisition terminal in the analog front end.

[0069] It should be noted that a single analog front-end (AFE) has 16 sampling channels, meaning a single AFE needs to simultaneously acquire 16 temperature signals (corresponding to the temperatures of 16 battery cells). To meet the 16-channel requirement of the AFE, this embodiment uses a combination of two 8-channel boards to fully cover the 16-channel sampling requirement; it supports simultaneous simulation of multiple battery cell temperatures, improving testing efficiency (e.g., measuring the temperature response of 16 battery cells at once). Furthermore, the board supports single-card isolated output, meaning the output channels of a single board are isolated from each other, allowing it to work independently with a single AFE for temperature simulation, avoiding interference from multiple channel signals.

[0070] For example, in a real-world testing scenario, taking an 8-channel single board as an example, the structure of the temperature simulation device is as follows: Figure 6 As shown, each channel is equipped with a diode, the input ports (IN01~IN08) are each connected to one channel of a single board, and the 8 output ports (OUT01~OUT08) are each connected to one acquisition channel of an analog front-end AFE.

[0071] It should be noted that the analog signal board is an isolated output card and can only be used with a single AFE to simulate temperature. When multiple AFEs are differentially connected in series with a series battery, the common ground condition cannot be met, which will damage the board. Therefore, the isolation characteristics of the board must be compatible with the grounding method of the AFEs. If a single analog signal board needs to support multiple AFEs simultaneously, the AFE channels must be connected to a common ground to avoid hardware damage and ensure signal acquisition accuracy. This application also provides a hardware-in-the-loop testing device for energy storage systems (see reference). Figures 3-5 The system includes a temperature simulation device and a battery management system under test (BMD). The BMD is used to manage the energy storage batteries in the energy storage system. In this embodiment, the hardware-in-the-loop testing device is used to test the BMD in the energy storage system. The energy storage system includes multiple battery clusters, each formed by connecting multiple battery packs. The BMD manages the entire energy storage system, the battery clusters, or each individual battery, to monitor, control, and protect the operating status of each battery.

[0072] Figure 12 This is a schematic flowchart of a temperature simulation method provided in an embodiment of this application.

[0073] like Figure 12 As shown, the method includes the following steps: Step S120: Calculate the target voltage that the analog output module needs to output based on the preset target temperature, the temperature-resistance relationship of the NTC resistor, and the relationship between different resistance values ​​and voltage dividers.

[0074] Step S121: Send the target voltage to the analog output module so that the analog output module receives the target voltage and outputs the corresponding analog voltage signal.

[0075] In step S122, the analog voltage signal passes through the first voltage divider resistor, generating a voltage divider signal equivalent to the NTC resistor across the first voltage divider resistor.

[0076] In step S123, the voltage divider signal is transmitted to the analog front end in the temperature acquisition circuit to simulate the voltage divider voltage of the NTC resistor corresponding to the target temperature.

[0077] In one possible implementation, calculating the target voltage to be output by the analog output module based on the pre-set target temperature, the temperature-resistance relationship of the NTC resistor, and the relationship between different resistance values ​​and voltage dividers includes: calculating the equivalent resistance of the NTC resistor using a first formula; the first formula represents the temperature-resistance relationship of the NTC resistor; calculating the equivalent voltage divider of the NTC resistor based on the equivalent resistance, the voltage provided by the constant power supply in the temperature acquisition circuit, and a second formula; calculating the current flowing through the protection element based on the equivalent voltage divider and the resistance of the first voltage divider resistor; calculating the voltage drop of the protection element based on the relationship between the current and voltage drop of the protection element; and using the sum of the equivalent voltage divider and the voltage drop of the protection element as the target voltage.

[0078] In one possible implementation, calculating the voltage drop of the protective element based on the correspondence between the current and the voltage drop of the protective element includes: calculating the resistance of the protective element based on the current flowing through the protective element and a third formula; the third formula is used to represent the correspondence between the current and the resistance of the protective element; and calculating the voltage drop of the protective element based on the resistance of the protective element and a fourth formula.

[0079] In one possible implementation, the first formula is: .

[0080] The second formula is: .

[0081] in, , and The resistivity of the NTC resistor is given by T, where T represents temperature. This indicates the resistance value of the NTC resistor. This indicates the voltage supplied by the constant power supply in the temperature acquisition circuit. This indicates the resistance value of the second voltage-dividing resistor connected in series with the first voltage-dividing resistor in the temperature acquisition circuit. This represents the equivalent voltage divider voltage of the NTC resistor at temperature T; The third formula is: .

[0082] The fourth formula is: .

[0083] in, , , and The coefficient of the resistance value of the protective component. This indicates that the voltage across the first voltage divider resistor is The current flowing through the protective element corresponds to the current at that time. Indicates the current of the protective element is The corresponding resistance value at that time This indicates the voltage drop across the protective component.

[0084] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0085] It should be noted that the specific implementation process of the above method embodiments can be referred to the description in the above-mentioned device embodiments, and will not be explained again here.

[0086] Figure 13 This is a schematic diagram of the structure of a control device provided in an embodiment of this application. Figure 13 As shown, the apparatus 1300 of this embodiment includes a processor 1310 and a memory 1320, wherein the memory 1320 stores a computer program 1321 that can run on the processor 1310. When the processor 1310 executes the computer program 1321, it implements the steps in any of the above method embodiments. Alternatively, when the processor 1310 executes the computer program 1321, it implements the functions of each module / unit in the above apparatus embodiments.

[0087] For example, computer program 1321 may be divided into one or more modules / units, one or more of which are stored in memory 1320 and executed by processor 1310 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of computer program 1321 in control device 1300.

[0088] Those skilled in the art will understand that Figure 13 This is merely an example of a device and does not constitute a limitation. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0089] The processor 1310 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0090] For the sake of simplicity and clarity, only the above-described functional modules / units are used as examples. In practical applications, the functions described above can be assigned to different functional modules / units as needed. These modules / units can be implemented in hardware, software, or a combination of both.

[0091] An embodiment of this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods described in the above-described method embodiments.

[0092] This invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the methods described in the above-described method embodiments.

[0093] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0094] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0095] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A temperature simulation device, characterized in that, include: The analog output module is used to receive the target voltage and output the corresponding analog voltage signal; The first voltage divider resistor has its first end connected to the output terminal of the analog output module and its second end grounded. The two ends of the first voltage divider resistor are also used to connect to the signal acquisition terminal of the analog front end in the temperature acquisition circuit; The control module, electrically connected to the analog output module, is used to calculate the target voltage based on the target temperature and send the target voltage to the analog output module. The target voltage is calculated based on a predetermined relationship between the temperature and resistance value of the NTC resistor and the relationship between different resistance values ​​and voltage dividers.

2. The temperature simulation device according to claim 1, characterized in that, Also includes: A protective element, connected in series between the analog output module and the first voltage divider resistor, is used to prevent the constant power supply in the temperature acquisition circuit from flowing backward into the analog output module.

3. The temperature simulation device according to claim 2, characterized in that, The step of the control module calculating the target voltage based on the target temperature includes: Based on the target temperature, the equivalent resistance of the NTC resistor is calculated using a first formula; the first formula is used to express the relationship between the temperature and the resistance of the NTC resistor. The equivalent voltage divider voltage of the NTC resistor is calculated based on the equivalent resistance value, the voltage provided by the constant power supply in the temperature acquisition circuit, and the second formula. The current flowing through the protective element is calculated based on the equivalent voltage divider and the resistance value of the first voltage divider resistor. Calculate the voltage drop of the protective element based on the relationship between the current and voltage drop of the protective element; The sum of the equivalent voltage divider and the voltage drop of the protective element is taken as the target voltage.

4. The temperature simulation device according to claim 3, characterized in that, The first formula is: ； The second formula is: ； in, , and The resistivity of the NTC resistor is given by T, where T represents temperature. This indicates the resistance value of the NTC resistor. This indicates the voltage supplied by the constant power supply in the temperature acquisition circuit. This indicates the resistance value of the second voltage-dividing resistor connected in series with the first voltage-dividing resistor in the temperature acquisition circuit. This represents the equivalent voltage divider voltage of the NTC resistor at temperature T; The relationship between the current and voltage drop of the protective element is expressed by the third and fourth formulas, wherein the third formula is: ； The fourth formula is: ； in, , , and The coefficient of the resistance value of the protective component. This indicates that the voltage across the first voltage divider resistor is The current flowing through the protective element corresponds to the current at that time. Indicates the current of the protective element is The corresponding resistance value at that time This indicates the voltage drop across the protective component.

5. The temperature simulation device according to any one of claims 1 to 4, characterized in that, The analog output module is an analog signal board; The analog signal board includes N mutually isolated output channels, and the output terminal of each output channel is connected to the first terminal of a first voltage divider resistor through a protection element; N is a positive integer greater than 0. The second terminals of all the first voltage divider resistors are connected to a common ground; The first end of each first voltage divider resistor is also used to connect to a signal acquisition terminal in the analog front end.

6. The temperature simulation device according to any one of claims 1 to 4, characterized in that, The protective element is a diode; The anode of the diode is connected to the output terminal of the analog output module, and the cathode is connected to the first terminal of the first voltage divider resistor.

7. A temperature simulation method, characterized in that, Applied to the temperature simulation apparatus according to any one of claims 1 to 6; the method comprises: Based on the preset target temperature, the temperature-resistance relationship of the NTC resistor, and the relationship between different resistance values ​​and voltage dividers, the target voltage that the analog output module needs to output is calculated. The target voltage is sent to the analog output module so that the analog output module receives the target voltage and outputs a corresponding analog voltage signal; The analog voltage signal passes through the first voltage divider resistor, generating a voltage divider signal equivalent to that of the NTC resistor across the first voltage divider resistor; The voltage divider signal is transmitted to the analog front end in the temperature acquisition circuit to simulate the voltage divider voltage of the NTC resistor corresponding to the target temperature.

8. The temperature simulation method according to claim 7, characterized in that, The step involves calculating the target voltage that the analog output module needs to output based on the pre-set target temperature, the temperature-resistance relationship of the NTC resistor, and the relationship between different resistance values ​​and voltage dividers. This includes: The equivalent resistance of the NTC resistor is calculated using the first formula; the first formula is used to express the relationship between the temperature and the resistance of the NTC resistor. The equivalent voltage divider voltage of the NTC resistor is calculated based on the equivalent resistance value, the voltage provided by the constant power supply in the temperature acquisition circuit, and the second formula. The current flowing through the protection element is calculated based on the equivalent voltage divider and the resistance value of the first voltage divider resistor. Calculate the voltage drop of the protective element based on the relationship between the current and voltage drop of the protective element; The sum of the equivalent voltage divider and the voltage drop of the protective element is taken as the target voltage.

9. The temperature simulation method according to claim 8, characterized in that, The step of calculating the voltage drop of the protective element based on the relationship between the current and voltage drop of the protective element includes: The resistance of the protective element is calculated based on the current flowing through it and the third formula; the third formula is used to express the correspondence between the current and the resistance of the protective element. The voltage drop of the protective element is calculated based on the resistance value of the protective element and the fourth formula.

10. A hardware-in-the-loop testing device for an energy storage system, characterized in that, include: The temperature simulation device and the battery management system under test as described in any one of claims 1 to 6; The battery management system under test is used to manage the energy storage batteries of the energy storage system.

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