Temperature effect calibration circuit and method for voltage measurement, and battery management system and vehicle

Abstract

Provided in the present invention are a temperature effect calibration circuit and method for voltage measurement, and a battery management system and a vehicle. The temperature effect calibration circuit for voltage measurement comprises: a temperature measurement module, which performs measurement and outputs a temperature measurement signal; a sampling module, which samples a voltage to be measured; a reference voltage generation module, which generates a reference voltage; a quantization module, which converts into a digital signal an analog signal output by the sampling module; a compensation parameter calculation module, which performs quadratic fitting and calculation to obtain compensation parameters; and a temperature effect correction module, which corrects an output signal of the quantization module at a current temperature to obtain a corrected voltage measurement signal. In the present invention, there is no need to add a complex circuit design to an analog circuit domain, and thus the design is easier to implement; the requirement for a temperature coefficient of a device in the process is reduced, and thus the technical solution can be applied to various different process nodes; and calibration is performed at a digital backend, and only one instance of full-temperature-range scanning is required during the factory testing of a chip, without spending a large amount of time on a high / low-temperature test, thereby effectively reducing costs.

Description

Voltage measurement temperature effect calibration circuit, method, battery management system and vehicle TECHNICAL FIELD

[0001] The present application relates to the field of microelectronics, in particular to a voltage measurement temperature effect calibration circuit, method, battery management system and vehicle. BACKGROUND

[0002] Measuring voltage is the most routine and basic operation in the field of microelectronics, and the accuracy of the voltage measurement value directly affects the judgment and execution results of subsequent circuits, therefore, it is necessary to ensure the high accuracy of the voltage measurement value; especially in the vehicle-grade battery management system chip (BMS IC, Battery Management System), the absolute value requirement for the voltage measurement accuracy of the battery cell in the battery pack is relatively high (generally < ± 5mV), so as to meet the requirements of battery working state monitoring from the safety point of view, and meet the requirements of battery power estimation accuracy from the use efficiency point of view.

[0003] The vehicle-grade battery management system chip has a high temperature range (generally > 100℃) use scenario in use. The high temperature range use scenario can cause the reference voltage to have a temperature drift effect due to the temperature coefficient (Temperature Coefficient) of the device in the circuit when measuring the voltage, thereby causing the digital code (Digital Code) obtained by measuring the voltage to deviate from the corresponding actual ideal value, and ultimately causing the measured voltage value to have an error and low accuracy.

[0004] Therefore, how to avoid or reduce the influence of the reference voltage temperature drift and realize high-precision voltage measurement (especially in the vehicle-grade battery management system chip) has become one of the problems to be solved by the person skilled in the art.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application, and for the convenience of understanding by the person skilled in the art. The above technical scheme cannot be considered as known to the person skilled in the art only because it is described in the background section of the present application. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a voltage measurement temperature effect calibration circuit, method, battery management system and vehicle, which is used to solve the problem of reference voltage temperature drift affecting the voltage measurement accuracy in the prior art.

[0007] To achieve the above object and other related objects, the present application provides a voltage measurement temperature effect calibration circuit, which at least comprises:

[0008] a temperature detection module, a sampling module, a reference voltage generation module, a quantization module, a compensation parameter calculation module and a temperature effect correction module;

[0009] The temperature detection module detects the working environment temperature of the reference voltage generation module and outputs a temperature detection signal, which is a digital signal.

[0010] The sampling module is connected to a voltage to be measured and samples the voltage to be measured.

[0011] The reference voltage generation module generates a reference voltage.

[0012] The quantization module is connected to the output terminals of the sampling module and the reference voltage generation module, converts an analog signal output by the sampling module into a digital signal based on the reference voltage.

[0013] The compensation parameter calculation module is connected to the output terminals of the temperature detection module and the reference voltage generation module, performs quadratic fitting based on data of at least three groups of temperature detection signals and corresponding reference voltages, and calculates a compensation parameter.

[0014] The temperature effect correction module is connected to the output terminals of the temperature detection module, the quantization module and the compensation parameter calculation module, determines a temperature compensation coefficient based on a temperature detection signal at a current temperature and the compensation parameter, and corrects an output signal of the quantization module at the current temperature to obtain a corrected voltage detection signal.

[0015] Optionally, the temperature detection module comprises a temperature sensor and a quantizer, the temperature sensor detects the working environment temperature of the reference voltage generation module and obtains a corresponding voltage value, and the quantizer is connected to the output terminal of the temperature sensor and converts the voltage value output by the temperature sensor into the temperature detection signal.

[0016] Optionally, the compensation parameter calculation module is implemented based on a DSP or a MCU.

[0017] Optionally, the temperature effect correction module comprises a multiplier, which multiplies the output signal of the quantization module by the temperature compensation coefficient to obtain the voltage detection signal.

[0018] More optionally, the voltage measurement temperature effect calibration circuit further comprises a non-volatile storage module connected between the output terminal of the compensation parameter calculation module and the input terminal of the temperature effect correction module, for storing the compensation parameter.

[0019] To achieve the above object and other related objects, the present application further provides a voltage measurement temperature effect calibration method, which is realized based on the voltage measurement temperature effect calibration circuit, and characterized in that the voltage measurement temperature effect calibration method at least comprises:

[0020] S1: performing a full temperature range scanning, and recording data of temperature detection signals and reference voltages corresponding to at least three groups of scattered temperature points; performing a second-order fitting on the three groups of data to calculate compensation parameters;

[0021] S2: when measuring a to-be-measured voltage, calculating a temperature compensation coefficient at a current temperature according to the compensation parameters and a temperature detection signal at a current working environment temperature; collecting the to-be-measured voltage and converting it into a digital signal, and correcting the digital signal of the to-be-measured voltage based on the temperature compensation coefficient to obtain a temperature-compensated voltage detection signal.

[0022] Optionally, the method of the second-order fitting in step S1 comprises:

[0023] S11: establishing a second-order polynomial model, satisfying: y=(ax 2 +bx+c)·d, wherein y is an actual value of a reference voltage, d is a theoretical value of the reference voltage, x is a temperature, and a, b and c are the compensation parameters;

[0024] S12: determining the compensation parameters based on a least square method.

[0025] More optionally, the temperature compensation coefficient satisfies: R(t)=at 2 +bt+c.

[0026] Wherein R(t) is the temperature compensation coefficient, a, b and c are the compensation parameters, and t is a temperature detection signal at a current working environment temperature.

[0027] More optionally, the voltage detection signal satisfies: D OUT_CORRECT =D OUT ·R(t).

[0028] Wherein D OUT_CORRECT is the voltage detection signal, and D OUT is the digital signal of the to-be-measured voltage.

[0029] To achieve the above object and other related objects, the present application further provides a battery management system, which at least comprises:

[0030] a battery pack, a control circuit and the voltage measurement temperature effect calibration circuit.

[0031] The voltage measurement temperature effect calibration circuit is connected to the battery pack, and the voltage of at least one battery cell in the battery pack is sampled and calibrated.

[0032] The control circuit is connected to the output end of the voltage measurement temperature effect calibration circuit, and controls the charging and discharging of the battery pack and / or protects the safety of the battery pack based on the voltage detection signal output by the voltage measurement temperature effect calibration circuit.

[0033] To achieve the above object and other related objects, the application further provides a vehicle, which at least comprises the above battery management system.

[0034] As described above, the voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the application have the following beneficial effects:

[0035] 1. The voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the application reduce the performance requirements of the reference voltage generation module, do not need to increase the complex circuit design in the analog circuit domain, and make the design easier to implement.

[0036] 2. The voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the application reduce the requirements for the temperature coefficient of the device in the process, so that the technical solution can be applied to various different process nodes.

[0037] 3. The voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the application calibrate the error caused by the reference voltage temperature drift effect in the digital back end, only need to scan the full temperature range once in the chip factory test process, do not need to spend a lot of high and low temperature test time, and effectively save the cost. BRIEF DESCRIPTION OF DRAWINGS

[0038] FIG. 1 shows a schematic diagram of generating zero temperature coefficient voltage by superimposing positive and negative temperature coefficient voltage.

[0039] FIG. 2 shows a schematic diagram of the actual reference voltage waveform generated by superimposing positive and negative temperature coefficient voltage.

[0040] FIG. 3 shows a schematic diagram of compensating the reference voltage in the high and low temperature range.

[0041] FIG. 4 shows a schematic diagram of the waveform of the compensation current in the high and low temperature range.

[0042] FIG. 5 shows a schematic diagram of the actual reference voltage waveform after corresponding compensation in the high and low temperature range.

[0043] FIG. 6 shows a schematic diagram of the structure of the voltage measurement temperature effect calibration circuit of the application.

[0044] FIG. 7 shows a structural schematic diagram of the battery management system of the present application.

[0045] Element No. Description 1 Voltage measurement temperature effect calibration circuit 11 Temperature detection module 111 Temperature sensor 112 Quantizer 12 Sampling module 13 Reference voltage generation module 14 Quantization module 15 Compensation parameter calculation module 16 Temperature effect correction module 17 Non-volatile storage module 2 Battery pack 3 Control circuit DETAILED DESCRIPTION

[0046] The present application is described below by way of specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied by other different embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application.

[0047] Please refer to FIG. 1-7. It is to be noted that the diagrams provided in the embodiments only schematically illustrate the basic concept of the present application, and the diagrams only show the components related to the present application rather than the number, shape and size of the components in actual implementation. The actual implementation of the components can be randomly changed in shape, number and proportion, and the layout of the components can be more complicated.

[0048] In order to avoid or reduce the influence of the reference voltage temperature drift, a reference voltage generation circuit with low temperature drift effect can be designed from the source. Specifically, a zero-temperature coefficient (Zero-TC) reference voltage generation circuit is constructed, and an output voltage Va(T) with positive temperature coefficient and an output voltage Vb(T) with negative temperature coefficient are realized by circuit design. The two are superimposed to ensure that the final output reference voltage is zero-temperature coefficient. In order to realize the zero-temperature coefficient of the superimposed voltage, the temperature first derivative coefficients of Va(T) and Vb(T) need to strictly comply with each other, i.e. satisfy: Va(T)+Vb(T)=C (1);

[0049] Wherein, C is a constant; so as to obtain the ideal result as shown by the dotted line in Fig. 1. In the chip factory test stage, the reference voltage generating circuit is adjusted in the analog domain according to the test result of the reference voltage generating circuit in the full temperature range, to compensate the temperature drift effect; however, the requirement of the complexity of the analog circuit design in the chip is higher, the requirement of the temperature coefficient of the process used in the chip is higher, and there are many non-ideal factors in the design and manufacturing, and finally the reference voltage obtained at high and low temperature ranges presents nonlinearity (such as quadratic convex function), as shown in Fig. 2.

[0050] In order to overcome the nonlinearity of Fig. 2, the reference voltage in the high and low temperature ranges can be compensated correspondingly, so as to further reduce the temperature drift effect caused by the temperature coefficient. Specifically, first, the reference voltage data corresponding to the temperature is obtained by the first full temperature scanning, as shown in Fig. 2; then in the low temperature range, a compensation current I NTC In the high temperature range, a compensation current I PTC is introduced on the compensation resistance Rc to introduce a positive temperature coefficient, so as to obtain the compensation voltage, as shown in Fig. 3 and Fig. 4, and the reference voltage is adjusted based on the compensation voltage; after the adjustment, the second full temperature scanning is needed to obtain the reference voltage data corresponding to the temperature after the compensation, as shown in Fig. 5, to confirm that the result of the temperature compensation adjustment meets the accuracy requirement; if the result after the first compensation does not meet the accuracy requirement, the adjustment needs to be iterated again, and the full temperature range scanning needs to be performed again until the accuracy requirement is met. Since the cost of high and low temperature test is much higher than that of normal temperature chip test, and the high and low temperature range compensation adjustment of the reference voltage generating circuit needs to be tested by at least two full temperature scans, the high and low temperature test time and test cost of the chip test will be greatly increased.

[0051] Based on the above reasons, the present application provides a voltage measurement temperature effect calibration circuit, which can effectively reduce the complexity, difficulty and test cost of the design.

[0052] As shown in Fig. 6, the voltage measurement temperature effect calibration circuit 1 of the present application comprises:

[0053] a temperature detection module 11, a sampling module 12, a reference voltage generating module 13, a quantization module 14, a compensation parameter calculation module 15 and a temperature effect correction module 16.

[0054] As shown in Fig. 6, the temperature detection module 11 detects the working environment temperature of the reference voltage generating module 13 and outputs a temperature detection signal D T , wherein the temperature detection signal D T is a digital signal.

[0055] Specifically, in the embodiment, the temperature detection module 11 comprises a temperature sensor 111 and a quantizer 112. The temperature sensor 111 detects the working environment temperature of the reference voltage generation module 13 and obtains the corresponding voltage value V T (analog quantity), i.e. the voltage value V T output by the temperature sensor 111. The voltage value V T is related to the working environment temperature and can characterize the high and low of the working environment temperature; wherein the voltage-temperature relationship satisfies: V T =k·T+A (3), wherein k and A are constants. The quantizer 112 is connected to the output end of the temperature sensor 111 and converts the voltage value V T output by the temperature sensor 111 into a temperature detection signal D T ; satisfying: D T =Q(V T ) (4), i.e. the temperature detection signal D T is the quantized digital quantity of the voltage value V T . In the embodiment, the high-order term of D T -T is ignored (because the high-order term error is small compared to the final reference voltage compensation) and is approximately linear. In actual use, any temperature detection signal that can detect the working environment temperature and output a digital quantity can be used, and is not limited to the structure of the embodiment. The quantizer comprises at least one of the following structures: an analog-to-digital converter (ADC) which converts the input analog voltage into a digital quantity by setting parameters such as quantization step and reference voltage; a combination of a comparator and a counter, wherein the comparator is used to compare the input analog voltage with a series of reference voltages, and the counter starts counting when the input voltage is greater than a certain reference voltage, thereby converting the analog voltage into a digital quantity; a special quantization chip which integrates complex circuits and algorithms inside to convert analog signals into digital signals.

[0056] As shown in FIG. 6, the sampling module 12 is connected to the to-be-measured voltage, samples the to-be-measured voltage, and obtains a sampling voltage V in (analog quantity). The sampling module 12 comprises at least one of the following hardware structures: an analog-to-digital converter (ADC) which has settable sampling frequency and resolution parameters and is used to convert the to-be-measured voltage into a digital form of sampling voltage; a special sampling chip which integrates specific sampling circuits and logic inside and can efficiently sample the to-be-measured voltage; an ADC module inside a microcontroller (MCU) which is connected to the to-be-measured voltage and performs sampling operation under software control.

[0057] As shown in FIG. 6, the reference voltage generation module 13 generates a reference voltage V REF (T), and the structure is not limited.

[0058] Specifically, the reference voltage generation module 13 is designed and configured based on theoretical values, but the output reference voltage V REF (T) Due to temperature effects, there will be drift, which will differ from the theoretical reference voltage V. REF_ideal There is a deviation, and the amount of deviation varies at different temperatures.

[0059] As shown in Figure 6, the quantization module 14 is connected to the output terminals of the sampling module 12 and the reference voltage generation module 13, based on the reference voltage V. REF (T) The analog signal output by sampling module 12 (i.e., sampling voltage V) in Converted to digital signal D OUT The quantization module includes at least one of the following structures: an analog-to-digital converter (ADC) that converts the input analog voltage into a digital quantity by setting parameters such as quantization step size and reference voltage; a comparator and counter combination, wherein the comparator compares the input analog voltage with a series of reference voltages, and the counter starts counting when the input voltage is greater than a certain reference voltage, thereby converting the analog voltage into a digital quantity; and a dedicated quantization chip that integrates complex circuits and algorithms for converting analog signals into digital signals.

[0060] Specifically, without considering noise and other channel nonlinearities, the actual measured value of the voltage under test (ignoring the deviation introduced by the sampling module) is quantized into a digital signal D. OUT satisfy:

[0061] Among them, D MAX This is the maximum range of the quantization module 14.

[0062] As shown in Figure 6, the compensation parameter calculation module 15 is connected to the output terminals of the temperature detection module 11 and the reference voltage generation module 13. It performs secondary fitting based on at least three sets of temperature detection signals and corresponding reference voltage data to calculate the compensation parameters.

[0063] Specifically, the compensation parameter calculation module 15 obtains the temperature detection signal D from the temperature detection module 11. T The reference voltage V is obtained from the reference voltage generation module 13. REF (T), and the temperature detection signal D T With reference voltage V REF (T) has a one-to-one correspondence; then a second-order polynomial model is established, and the compensation parameters are estimated based on the second-order polynomial model and the corresponding data set. In this embodiment, the least squares method is used to determine the parameters, and the compensation function can be constructed after obtaining the coefficients of the compensation function.

[0064] Specifically, the compensation parameter calculation module 15 is implemented based on, but not limited to, a DSP (Digital Signal Processing), a MCU (Microcontroller Unit), a PC (Personal Computer) mode, which will not be described here.

[0065] As shown in FIG. 6, the temperature effect correction module 16 is connected to the output ends of the temperature detection module 11, the quantization module 14 and the compensation parameter calculation module 15, and based on the temperature detection signal D T and the compensation parameter determines a temperature compensation coefficient R(t), and corrects the output signal D OUT of the quantization module 14 at the current temperature to obtain a corrected voltage detection signal D OUT_CORRECT .

[0066] Specifically, in the embodiment, the temperature effect correction module 16 includes a multiplier, which multiplies the output signal D OUT of the quantization module 14 with the temperature compensation coefficient R(t) to obtain the voltage detection signal D OUT_CORRECT . The inputs of the multiplier 14 include the digital signal output by the quantization module and the temperature compensation coefficient, both of which are digital quantities, and the output of the multiplier is the corrected voltage detection signal, which is also a digital quantity. In actual use, any mode capable of achieving temperature compensation based on the temperature compensation coefficient R(t) is applicable to the present application, which is not limited to the embodiment.

[0067] As another implementation mode of the present application, the voltage measurement temperature effect calibration circuit 1 further includes a non-volatile storage module 17 connected between the output end of the compensation parameter calculation module 15 and the input end of the temperature effect correction module 16, for storing the compensation parameter. That is, the compensation parameter is calculated once, and even if power is cut off, the compensation parameter can be directly called and used in subsequent use, improving convenience.

[0068] As shown in FIG. 6, if the voltage OUT is calculated based on the digital signal D , then there is a temperature effect error introduced by the reference voltage V REF (T), which satisfies:

[0069] According to the above formula (6), the ideal voltage detection signal satisfies:

[0070] wherein the reference voltage V REF (T) is different from the reference voltage theoretical value V REF_idealThere is a nonlinear error (second order error) caused by the temperature coefficient between them, that is:

[0071] V REF (T) = (aT 2 +bT+c)·V REF_ideal (8); wherein a, b, c are compensation parameters;

[0072] Therefore, for different temperatures T, there is a compensation function R(T) that satisfies:

[0073] So that: D OUT_CORRECT =D OUT ·R(T) (10);

[0074] Wherein the compensation parameters can be obtained by fitting the test scan of the reference voltage V REF (T).

[0075] Based on the above principle, the voltage measurement temperature effect calibration circuit 1 of the application is used to realize the voltage measurement temperature effect calibration method, comprising:

[0076] S1: Perform a full temperature range scan and record at least three groups of temperature detection signals D T and reference voltage V REF (T) corresponding to the scattered temperature points; second order fitting is performed on the three groups of data to calculate the compensation parameters. The full temperature range scan includes the following steps: placing the chip in a test environment that can accurately control the temperature (such as an incubator), recording the temperature detection signal output by the temperature detection module of the chip at room temperature, the reference voltage output by the reference voltage generation module, and the digital signal output by the quantization module; set the heating rate, start the heating program (determined according to the chip specifications and test standards), record the above three signals at certain time intervals during the heating process, continue to record after continuously heating to the set highest temperature and keeping for a period of time; set the cooling rate (determined according to the chip specifications and test standards), start the cooling program, record the above three signals at certain time intervals during the cooling process, continue to record after continuously cooling to the set lowest temperature and keeping for a period of time; analyze the recorded data in the full temperature range, calculate the compensation parameters by second order fitting and other methods, and judge whether the chip meets the temperature performance requirements according to the analysis results.

[0077] Specifically, the method of second order fitting includes:

[0078] S11: Establish a second order polynomial model, in this embodiment, based on the above formula (8), the second order polynomial satisfies: y = (ax 2+bx+c)·d (11), wherein y is a reference voltage actual value (dependent variable), x is temperature (independent variable), a, b, and c are compensation parameters (to-be-determined coefficients), and d is a reference voltage theoretical value (known quantity).

[0079] S12: Compensation parameters a, b, and c are determined so that the sum of squares of errors between the fitting curve and the data points is minimum, and in this embodiment, the compensation parameters are determined by using the least square method. In actual use, any method capable of estimating the compensation parameters based on the second-order polynomial and the data set is applicable to the present application, and is not limited to this embodiment. Thus, the compensation function of the above formula (9) is obtained.

[0080] It should be noted that after the compensation parameters are estimated, a curve can be fitted, and the compensation parameters can be adjusted by evaluating the fitting effect so that the fitting curve better matches the data points, which is not described herein. In addition, step S1 can be performed in the test phase or in the early stage of measurement. In this embodiment, after the compensation parameters a, b, and c are determined, they are stored in the non-volatile storage module 17 for calling.

[0081] S2: When measuring the to-be-measured voltage, the temperature compensation coefficient R(t) at the current working environment temperature is calculated based on the compensation parameters and the temperature detection signal D T at the current temperature; the to-be-measured voltage is collected and converted into a digital signal, the digital signal D OUT of the to-be-measured voltage is corrected based on the temperature compensation coefficient R(t), and the temperature-compensated voltage detection signal D OUT_CORRECT is obtained.

[0082] Specifically, when the voltage is measured, there is a determined working environment temperature; as shown in FIG. 6, the temperature effect correction module 16 obtains the compensation parameters a, b, and c and the temperature detection signal D T at the current working environment temperature, and substitutes the compensation parameters a, b, and c and the temperature detection signal D T at the current working environment temperature into the compensation function (the above formula (9)) to obtain the temperature compensation coefficient R(t) at the current temperature t, which satisfies: R(t) = at 2 +bt+c (12).

[0083] Wherein a, b, c, and t are known quantities, and the compensation coefficient R(t) is a determined value (the compensation coefficients corresponding to different temperatures are different).

[0084] Specifically, as shown in FIG. 6, the temperature effect correction module 16 obtains the digital signal D OUT of the to-be-measured voltage output by the quantization module 14, compensates based on the above formula (10), and finally obtains the voltage detection signal D OUT_CORRECT that satisfies: D OUT_CORRECT =D OUT• R(t) (13).

[0085] The voltage measurement temperature effect calibration circuit and the voltage measurement temperature effect calibration method of the present application reduce the direct requirements for the reference voltage generation module itself, reduce the complexity and difficulty of circuit design, compensate for the temperature effect of the reference voltage generation circuit in the digital domain, have small overhead, high stability, reduce the cost required for high and low temperature compensation adjustment, and only need to perform a full temperature range scan, further reducing the test cost.

[0086] As shown in FIG. 7, the present application also provides a battery management system, which comprises:

[0087] The voltage measurement temperature effect calibration circuit 1, the battery pack 2 and the control circuit 3 of the present application.

[0088] As shown in FIG. 7, the voltage measurement temperature effect calibration circuit 1 is connected to the battery pack 2, and samples and calibrates the voltage of at least one cell in the battery pack 2. For specific structure and principle, refer to the above, which will not be repeated here.

[0089] As shown in FIG. 7, the control circuit 3 is connected to the output end of the voltage measurement temperature effect calibration circuit 1, and based on the voltage detection signal D OUT_CORRECT controls the charging and discharging of the battery pack 2 and / or protects the safety of the battery pack 2.

[0090] Specifically, the control circuit 3 acquires the calibrated voltage measurement signal (i.e. the voltage detection signal D OUT_CORRECT ), thereby grasps the state of the battery pack, and generates a corresponding control signal to control the charging and discharging of the battery pack 2 and / or protect the safety of the battery pack 2.

[0091] It should be noted that the battery management system of the present application can be applied to any occasion requiring a battery, including but not limited to a vehicle-grade battery management system.

[0092] The present application also provides a vehicle, which comprises the battery management system of the present application, and the vehicle includes but is not limited to a two-wheeled, three-wheeled and four-wheeled electric vehicle.

[0093] In summary, the present application provides a voltage measurement temperature effect calibration circuit, method, battery management system and vehicle, comprising: a temperature detection module, a sampling module, a reference voltage generation module, a quantization module, a compensation parameter calculation module and a temperature effect correction module; the temperature detection module detects the working environment temperature of the reference voltage generation module and outputs a temperature detection signal, which is a digital signal; the sampling module connects to the voltage to be measured and samples the voltage to be measured; the reference voltage generation module generates a reference voltage; the quantization module is connected to the output ends of the sampling module and the reference voltage generation module, and converts the analog signal output by the sampling module into a digital signal based on the reference voltage; the compensation parameter calculation module is connected to the output ends of the temperature detection module and the reference voltage generation module, and performs quadratic fitting based on at least three groups of temperature detection signals and corresponding reference voltage data to calculate the compensation parameter; the temperature effect correction module is connected to the output ends of the temperature detection module, the quantization module and the compensation parameter calculation module, determines the temperature compensation coefficient based on the temperature detection signal at the current temperature and the compensation parameter, and corrects the output signal of the quantization module at the current temperature to obtain a corrected voltage detection signal. The voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the present application reduce the performance requirements of the reference voltage generation module, do not need to increase complex circuit design in the analog circuit domain, make the design easier to implement, reduce the requirements for the device temperature coefficient in the process, make the technical solution applicable to various different process nodes, calibrate the error caused by the reference voltage temperature drift effect in the digital back end, only need to scan the full temperature range once in the chip factory test process, do not need to spend a lot of high and low temperature test time, and effectively save the cost. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has high industrial utilization value.

[0094] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea disclosed by the present application should be covered by the claims of the present application.

Claims

1. A voltage measurement temperature effect calibration circuit, characterized by, The voltage measurement temperature effect calibration circuit at least comprises: The temperature detection module, the sampling module, the reference voltage generation module, the quantization module, the compensation parameter calculation module and the temperature effect correction module; The temperature detection module detects the working environment temperature of the reference voltage generation module and outputs a temperature detection signal, which is a digital signal; The sampling module is connected to the voltage to be measured and samples the voltage to be measured; The reference voltage generation module generates a reference voltage; The quantization module is connected to the output terminals of the sampling module and the reference voltage generation module, converts the analog signal output by the sampling module into a digital signal based on the reference voltage; The compensation parameter calculation module is connected to the output terminals of the temperature detection module and the reference voltage generation module, and calculates the compensation parameter based on the data of at least three groups of temperature detection signals and corresponding reference voltages through quadratic fitting; The temperature effect correction module is connected to the output terminals of the temperature detection module, the quantization module and the compensation parameter calculation module, determines the temperature compensation coefficient based on the temperature detection signal at the current temperature and the compensation parameter, and corrects the output signal of the quantization module at the current temperature to obtain a corrected voltage detection signal.

2. The voltage measurement temperature effect calibration circuit of claim 1, wherein: The temperature detection module comprises a temperature sensor and a quantizer, the temperature sensor detects the working environment temperature of the reference voltage generation module and obtains a corresponding voltage value, and the quantizer is connected to the output terminal of the temperature sensor and converts the voltage value output by the temperature sensor into the temperature detection signal.

3. The voltage measurement temperature effect calibration circuit of claim 1, wherein: The temperature effect correction module comprises a multiplier, which multiplies the output signal of the quantization module by the temperature compensation coefficient to obtain the voltage detection signal.

4. The voltage measurement temperature effect calibration circuit according to any one of claims 1 to 3, characterized in that: The voltage measurement temperature effect calibration circuit further comprises a non-volatile storage module connected between the output terminal of the compensation parameter calculation module and the input terminal of the temperature effect correction module for storing the compensation parameter.

5. A method of calibrating the temperature effect on voltage measurement, implemented based on the voltage measurement temperature effect calibration circuit according to any one of claims 1-4, characterized in that, The voltage measurement temperature effect calibration method at least comprises: S1: Perform a full temperature range scan and record the data of at least three groups of scattered temperature points corresponding to the temperature detection signal and the reference voltage; perform second-order fitting on the three groups of data to calculate the compensation parameter; S2: When measuring the voltage to be measured, calculate the temperature compensation coefficient at the current temperature based on the compensation parameter and the temperature detection signal at the current working environment temperature; collect the voltage to be measured and convert it into a digital signal, correct the digital signal of the voltage to be measured based on the temperature compensation coefficient to obtain the voltage detection signal after temperature compensation.

6. The voltage measurement temperature effect calibration method of claim 5, wherein: The method of second-order fitting in step S1 comprises: S11: Establish a second-order polynomial model satisfying: y = (ax 2 +bx+c)·d, where y is the actual value of the reference voltage, d is the theoretical value of the reference voltage, x is the temperature, and a, b, and c are the compensation parameters; S12: Determine the compensation parameter based on the least square method.

7. The voltage measurement temperature effect calibration method according to claim 5 or 6, characterized in that: The temperature compensation coefficient satisfies: R(t) = at + bt + c. 2 +bt+c. Wherein, R(t) is the temperature compensation coefficient, a, b, c is the compensation parameter, t is the temperature detection signal at the current working environment temperature.

8. The voltage measurement temperature effect calibration method of claim 7, wherein: The voltage detection signal satisfies: D OUT_CORRECT = D OUT • R(t); Wherein, D OUT_CORRECT is the voltage detection signal, D OUT is the digital signal of the voltage to be measured.

9. The voltage measurement temperature effect calibration method of claim 5, wherein: The temperature detection signal satisfies: D T = Q(V T ); where D T is a temperature detection signal, V T is a voltage value, and Q is a quantization function.

10. The voltage measurement temperature effect calibration method of claim 6, wherein: The method of second-order fitting in step S1 further comprises: fitting the curve after determining the compensation parameter, and adjusting the compensation parameter by evaluating the fitting effect.

11. The voltage measurement temperature effect calibration method of claim 6, wherein: The compensation parameters a, b and c are stored in a non-volatile storage module for calling.

12. The voltage measurement temperature effect calibration method of claim 8, wherein: In the absence of noise and other channel nonlinearities, the digital signal D OUT satisfies: where D MAX is the maximum range of the quantization module, V REF (T) is the reference voltage, V in is the sampled voltage.

13. The voltage measurement temperature effect calibration method of claim 5, wherein: The full-temperature-range scanning in step S1 includes placing the chip in a thermostat, adjusting the temperature of the thermostat within the working temperature range of the chip to be tested, and recording data; and the compensation parameter calculation is performed once for each temperature.

14. A battery management system, characterized by, The battery management system at least comprises: The battery pack, the control circuit and the voltage measurement temperature effect calibration circuit according to any one of claims 1-4; The voltage measurement temperature effect calibration circuit is connected to the battery pack, samples and calibrates the voltage of at least one cell in the battery pack; The control circuit is connected to the output end of the voltage measurement temperature effect calibration circuit, controls the charging and discharging of the battery pack and / or protects the safety of the battery pack based on the voltage detection signal output by the voltage measurement temperature effect calibration circuit.

15. A vehicle characterized by comprising: The vehicle at least comprises the battery management system according to claim 14.

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