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

Abstract

The present invention provides a voltage measurement temperature effect calibration circuit, method, battery management system and vehicle, including: a temperature detection module, which detects and outputs a temperature detection signal; a sampling module, which samples the voltage to be measured; a reference voltage generation module, which generates a reference voltage; a quantization module, which converts the analog signal output by the sampling module into a digital signal; a compensation parameter calculation module, which obtains the compensation parameter by quadratic fitting calculation; and a temperature effect correction module, which corrects the output signal of the quantization module at the current temperature to obtain a corrected voltage detection signal. The present invention does not require the addition of complex circuit design within the analog circuit domain, making the design easier to implement; reduces the requirements for the temperature coefficient of the device in the process, so that the technical solution can be applied to a variety of different process nodes; calibration is performed at the digital back end, and only one full temperature range scan is required during the chip factory test process, eliminating the need to spend a lot of high and low temperature testing time, effectively saving costs.

Description

Technical Field

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

[0002] Measuring voltage is the most common and fundamental operation in the field of microelectronics. The accuracy of voltage measurements directly affects the judgment and execution results of subsequent circuits. Therefore, it is necessary to ensure high accuracy of voltage measurements. In particular, in automotive-grade battery management system chips (BMS ICs), the absolute value of the voltage measurement accuracy of the battery cells in the battery pack must be high (generally <±5mV). This is to meet the requirements for battery operating status monitoring from a safety perspective and to meet the requirements for battery power estimation accuracy from an efficiency perspective.

[0003] Automotive-grade battery management system chips are used in high temperature ranges (generally >100°C). These high temperature ranges can cause the reference voltage to drift during voltage measurement due to the temperature coefficients of circuit components. This can cause the digital code obtained from the voltage measurement to deviate from the actual ideal value, ultimately resulting in errors and low precision in the measured voltage.

[0004] Therefore, how to avoid or reduce the impact of reference voltage temperature drift and achieve high-precision voltage measurement (especially in automotive-grade battery management system chips) has become one of the urgent problems to be solved by technical personnel in this field.

[0005] It should be noted that the above technical background is merely provided to provide a clear and complete description of the technical solutions of the present invention and to facilitate understanding by those skilled in the art. Simply because these solutions are described in the technical background section of the present invention, it should not be assumed that the above technical solutions are well known to those skilled in the art. Summary of the Invention

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

[0007] To achieve the above-mentioned and other related objectives, the present invention provides a voltage measurement temperature effect calibration circuit, the voltage measurement temperature effect calibration circuit comprising at least:

[0008] Temperature detection module, sampling module, reference voltage generation module, quantization module, compensation parameter calculation module and 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 the voltage to be measured and samples the voltage to be measured;

[0011] The reference voltage generating module generates a reference voltage;

[0012] 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;

[0013] The compensation parameter calculation module is connected to the output end of the temperature detection module and the reference voltage generation module, and calculates the compensation parameter based on a quadratic fit of at least three sets of temperature detection signals and corresponding reference voltage data;

[0014] 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 and the compensation parameter at the current temperature, and corrects the output signal of the quantization module at the current temperature to obtain a corrected voltage detection signal.

[0015] Optionally, the temperature detection module includes a temperature sensor and a quantizer, the temperature sensor detects the working environment temperature of the reference voltage generating module and obtains a corresponding voltage value; the quantizer is connected to the output end 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 DSP or MCU.

[0017] Optionally, the temperature effect correction module includes 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 includes a non-volatile storage module, which is connected between the output end of the compensation parameter calculation module and the input end of the temperature effect correction module and is used to store the compensation parameters.

[0019] To achieve the above-mentioned and other related objects, the present invention further provides a voltage measurement temperature effect calibration method, which is implemented based on the above-mentioned voltage measurement temperature effect calibration circuit, and is characterized in that the voltage measurement temperature effect calibration method at least includes:

[0020] S1: Perform a full temperature range scan and record at least three sets of temperature detection signals and reference voltage data corresponding to dispersed temperature points; perform a second-order fitting on the three sets of data to calculate the compensation parameters;

[0021] S2: When measuring the voltage to be measured, the temperature compensation coefficient at the current temperature is calculated according to the compensation parameter and the temperature detection signal at the current working environment temperature; the voltage to be measured is collected and converted into a digital signal, and the digital signal of the voltage to be measured is corrected based on the temperature compensation coefficient to obtain a voltage detection signal after temperature compensation.

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

[0023] S11: Establish a second-order polynomial model that satisfies: 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;

[0024] S12: Determine the compensation parameter based on the least square method.

[0025] More optionally, the temperature compensation coefficient satisfies:

[0026] R(t)=at 2 +bt+c.

[0027] Wherein, R(t) is the temperature compensation coefficient, a, b, and c are the compensation parameters, and t is the temperature detection signal at the current working environment temperature.

[0028] More optionally, the voltage detection signal satisfies:

[0029] D OUT_CORRECT =D OUT ·R(t);

[0030] Among them, D OUT_CORRECT is the voltage detection signal, D OUT is the digital signal of the voltage to be measured.

[0031] To achieve the above and other related objectives, the present invention further provides a battery management system, which includes at least:

[0032] Battery pack, control circuit and the above voltage measurement temperature effect calibration circuit;

[0033] The voltage measurement temperature effect calibration circuit is connected to the battery pack to sample and calibrate the voltage of at least one cell in the battery pack;

[0034] 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.

[0035] To achieve the above-mentioned object and other related objects, the present invention also provides a vehicle, which at least includes: the above-mentioned battery management system.

[0036] As described above, the voltage measurement temperature effect calibration circuit, method, battery management system, and vehicle of the present invention have the following beneficial effects:

[0037] 1. The voltage measurement temperature effect calibration circuit, method, battery management system, and vehicle of the present invention reduce the performance requirements for the reference voltage generation module, and do not require additional complex circuit design in the analog circuit domain, making the design easier to implement.

[0038] 2. The voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the present invention reduce the requirements for the temperature coefficient of the devices in the process, so that the technical solution can be applied to a variety of different process nodes.

[0039] 3. The voltage measurement temperature effect calibration circuit, method, battery management system and vehicle of the present invention perform digital back-end calibration for the error caused by the reference voltage temperature drift effect. During the chip factory test process, only one full temperature range scan is required, and a large amount of high and low temperature testing time is not required, which effectively saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The diagram shows the principle of generating a zero temperature coefficient voltage by superimposing positive and negative temperature coefficient voltages.

[0041] Figure 2 The figure shows the actual reference voltage waveform generated by superimposing positive and negative temperature coefficient voltages.

[0042] Figure 3 The diagram shows the principle of compensating the reference voltage in high and low temperature ranges.

[0043] Figure 4 Shown is a waveform diagram of the compensation current in high and low temperature ranges.

[0044] Figure 5 The figure shows the actual reference voltage waveform after corresponding compensation in high and low temperature ranges.

[0045] Figure 6 Shown is a schematic structural diagram of the voltage measurement temperature effect calibration circuit of the present invention.

[0046] Figure 7 Shown is a structural schematic diagram of the battery management system of the present invention.

[0047] Component number description

[0048] 1 Voltage Measurement Temperature Effect Calibration Circuit

[0049] 11. Temperature detection module

[0050] 111 Temperature Sensor

[0051] 112 Quantizer

[0052] 12 Sampling Module

[0053] 13. Reference voltage generation module

[0054] 14 Quantization Module

[0055] 15 Compensation parameter calculation module

[0056] 16 Temperature Effect Correction Module

[0057] 17 Non-volatile storage module

[0058] 2 battery packs

[0059] 3 Control circuit DETAILED DESCRIPTION

[0060] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0061] See also Figures 1 to 7 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0062] In order to avoid or reduce the impact of reference voltage temperature drift, the design of a reference voltage generation circuit with low temperature drift effect can be considered from the source. Specifically, to construct a zero temperature coefficient (Zero-TC) reference voltage generation circuit, it is necessary to realize an output voltage Va(T) with a positive temperature coefficient and an output voltage Vb(T) with a negative temperature coefficient through circuit design. By superimposing the two, the final output reference voltage is guaranteed to have a zero temperature coefficient. In order to achieve the zero temperature coefficient of the superimposed voltage, the temperature derivative coefficients of Va(T) and Vb(T) must strictly obey the opposite of each other, that is, satisfy:

[0063] Va(T)+Vb(T)=C(1);

[0064]

[0065] Where C is a constant; thus we get Figure 1 The dashed line shows the ideal result. During the chip factory test phase, the reference voltage generation circuit is adjusted in the analog domain based on the test results of the reference voltage generation circuit under the full temperature range to compensate for the temperature drift effect. However, the analog circuit design in the chip requires high complexity, and the temperature coefficient of the process used in the chip is also required to be high. In addition, there are many non-ideal factors in the design and manufacturing process, and the reference voltage obtained is nonlinear (such as a quadratic convex function) in the high and low temperature ranges. Figure 2 shown.

[0066] To overcome Figure 2 The nonlinearity of the reference voltage can be compensated in the high and low temperature ranges to further reduce the temperature drift effect caused by the temperature coefficient. Specifically, first, through the first full temperature scan, the reference voltage data corresponding to the temperature is obtained, such as Figure 2 As shown; then in the low temperature range, a compensation current I with a negative temperature coefficient is introduced on the compensation resistor Rc. NTC In the high temperature range, a compensation current I with a positive temperature coefficient is introduced into the compensation resistor Rc. PTC , thus obtaining the compensation voltage, such as Figure 3 and Figure 4 As shown, the reference voltage is adjusted based on the compensation voltage; after adjustment, a second full temperature scan is required to obtain the compensated reference voltage data corresponding to the temperature, such as Figure 5 As shown, confirm that the temperature compensation adjustment results meet the accuracy requirements. If the accuracy of the result after the first compensation does not meet the requirements, it is necessary to iterate and adjust again, and scan the full temperature range again until the accuracy requirements are met. Because the cost of high and low temperature testing is much higher than that of normal temperature chip testing, and the high and low temperature range compensation adjustment of the reference voltage generation circuit requires at least two full temperature scan tests, the high and low temperature testing time and test cost of the chip testing will be significantly increased.

[0067] Based on the above reasons, the present invention provides a voltage measurement temperature effect calibration circuit, which can effectively reduce the complexity, difficulty and testing cost of the design.

[0068] like Figure 6 As shown, the voltage measurement temperature effect calibration circuit 1 of the present invention includes:

[0069] The system includes a temperature detection module 11 , a sampling module 12 , a reference voltage generation module 13 , a quantization module 14 , a compensation parameter calculation module 15 and a temperature effect correction module 16 .

[0070] like Figure 6 As shown, the temperature detection module 11 detects the working environment temperature of the reference voltage generation module 13 and outputs a temperature detection signal D T , where the temperature detection signal D T For digital signals.

[0071] Specifically, in this embodiment, the temperature detection module 11 includes 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), that is, the voltage value V output by the temperature sensor 111 T It is related to the working environment temperature and can be based on the voltage value V T The size represents the working environment temperature; the voltage-temperature relationship satisfies: V T =k·T+A(3), where k and A are constants. The quantizer 112 is connected to the output of the temperature sensor 111 and converts the voltage value V output by the temperature sensor 111 into T Converted into temperature detection signal D T ; Satisfied: D T =Q(V T )(4), namely the temperature detection signal D T is the voltage value V T The quantized digital value, in this embodiment, D T The high-order terms of -T are ignored (because the errors in the high-order terms are small compared to the final reference voltage compensation), and the relationship is approximately linear. In actual use, any device that can detect the working environment temperature and output a digital temperature detection signal can be used, and is not limited to the structure of this embodiment.

[0072] like Figure 6 As shown, the sampling module 12 is connected to the voltage to be measured, samples the voltage to be measured, and obtains the sampled voltage V in (Analog quantity).

[0073] like Figure 6As shown, the reference voltage generating module 13 generates a reference voltage V REF (T), no structure limit.

[0074] Specifically, the reference voltage generating module 13 is designed and configured based on theoretical values, but the output reference voltage V REF (T)Due to the influence of temperature, there will be drift, which is different from the theoretical value of reference voltage V REF_ideal There is a deviation, and the amount of deviation is different at different temperatures.

[0075] like Figure 6 As shown, the quantization module 14 is connected to the output end 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 the sampling module 12 (ie, the sampling voltage V in ) is converted into a digital signal D OUT .

[0076] Specifically, without considering noise and other channel nonlinearities, the actual measured value of the voltage to be measured (ignoring the deviation introduced by the sampling module) is quantized into a digital signal D OUT satisfy:

[0077]

[0078] Among them, D MAX is the maximum range of the quantization module 14.

[0079] like Figure 6 As shown, the compensation parameter calculation module 15 is connected to the output ends of the temperature detection module 11 and the reference voltage generation module 13, and calculates the compensation parameters based on quadratic fitting of at least three sets of temperature detection signals and corresponding reference voltage data.

[0080] Specifically, the compensation parameter calculation module 15 obtains the temperature detection signal D from the temperature detection module 11. T , obtain the reference voltage V from the reference voltage generating 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.

[0081] Specifically, the compensation parameter calculation module 15 is implemented based on methods including but not limited to DSP (Digital Signal Processing), MCU (Microcontroller Unit), and PC (Personal Computer), which are not described in detail here.

[0082] like Figure 6 As shown, the temperature effect correction module 16 is connected to the output end of the temperature detection module 11, the quantization module 14 and the compensation parameter calculation module 15, and is based on the temperature detection signal D at the current temperature. T The temperature compensation coefficient R(t) is determined by the compensation parameter, and the output signal D of the quantization module 14 at the current temperature is quantified. OUT Correction is performed to obtain the corrected voltage detection signal D OUT_CORRECT .

[0083] Specifically, in this embodiment, the temperature effect correction module 16 includes a multiplier, which multiplies the output signal D of the quantization module 14. OUT Multiply it by the temperature compensation coefficient R(t) to get the voltage detection signal D OUT_CORRECT In actual use, any method that can achieve temperature compensation based on the temperature compensation coefficient R(t) is applicable to the present invention and is not limited to this embodiment.

[0084] As another implementation of the present invention, the voltage measurement temperature effect calibration circuit 1 further includes a non-volatile storage module 17, which is connected between the output of the compensation parameter calculation module 15 and the input of the temperature effect correction module 16 and is used to store the compensation parameters. This allows the compensation parameters to be calculated only once and can be directly retrieved for subsequent use, even during a power outage, improving convenience.

[0085] like Figure 6 As shown, if based on the digital signal D OUT Calculate the voltage V in′' , then, there is a reference voltage V REF (T) The temperature effect error introduced satisfies:

[0086]

[0087] According to the above formula (6), the ideal voltage detection signal can be obtained satisfy:

[0088]

[0089] Among them, the reference voltage V REF (T) and the theoretical value of the reference voltage V REF_idealThere is a nonlinear error (second-order error) caused by the temperature coefficient, namely:

[0090] V REF (T)=(aT 2 +bT+c)·V REF_ideal (8); where a, b, c are compensation parameters;

[0091] Therefore, for different temperatures T, there exists a compensation function R(T) that satisfies:

[0092]

[0093] So that:

[0094] D OUT_CORRECT =D OUT ·R(T) (10);

[0095] The compensation parameters can be obtained by adjusting the reference voltage V REF (T) was fitted to the test scan.

[0096] Based on the above principles, the voltage measurement temperature effect calibration circuit 1 of the present invention is used to implement a voltage measurement temperature effect calibration method, including:

[0097] S1: Scan the entire temperature range and record the temperature detection signals D corresponding to at least three groups of dispersed temperature points. T and reference voltage V REF (T) data; perform second-order fitting on the three sets of data and calculate the compensation parameters.

[0098] Specifically, the second-order fitting methods include:

[0099] 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), Among them, y is the actual value of the reference voltage (dependent variable), x is the temperature (independent variable), a, b, and c are compensation parameters (undetermined coefficients), and d is the theoretical value of the reference voltage (known quantity).

[0100] S12: Determine compensation parameters a, b, and c so that the sum of squared errors between the fitted curve and the data points is minimized. In this embodiment, the least squares method is used to determine the compensation parameters. In practice, any method that can estimate the compensation parameters based on a second-order polynomial and a data set is applicable to the present invention, and is not limited to this embodiment. Thus, the compensation function of equation (9) above can be obtained.

[0101] It should be noted that after estimating the compensation parameters, a curve can be fitted and the compensation parameters can be adjusted by evaluating the fitting effect to ensure a better fit between the fitted curve and the data points. This will not be described in detail here. Furthermore, step S1 can be performed during the testing phase or at the initial stage of measurement. In this embodiment, the compensation parameters a, b, and c are determined and stored in the non-volatile storage module 17 for easy recall.

[0102] S2: When measuring the voltage to be measured, the temperature detection signal D is calculated based on the compensation parameters and the current working environment temperature. T Calculate the temperature compensation coefficient R(t) at the current temperature; collect the voltage to be measured and convert it into a digital signal, and calculate the digital signal D of the voltage to be measured based on the temperature compensation coefficient R(t). OUT Correction is performed to obtain the temperature compensated voltage detection signal D OUT_CORRECT .

[0103] Specifically, when performing voltage measurement, there is a certain working environment temperature; Figure 6 As shown, the temperature effect correction module 16 obtains the compensation parameters a, b, c and the current temperature detection signal D T And the compensation parameters a, b, c and the temperature detection signal D at the current working environment temperature T Substituting into the compensation function (Equation (9) above), we get the temperature compensation coefficient R(t) at the current temperature t, which satisfies:

[0104] R(t)=at 2 +bt+c (12);

[0105] Where a, b, c, and t are all known quantities, and the compensation coefficient R(t) is a fixed value (different temperatures correspond to different compensation coefficients).

[0106] Specifically, if Figure 6 As shown, the temperature effect correction module 16 obtains the digital signal D of the voltage to be measured output by the quantization module 14. OUT , based on the above formula (10), the final voltage detection signal D OUT_CORRECT satisfy:

[0107] D OUT_CORRECT =D OUT ·R(t) (13).

[0108] The voltage measurement temperature effect calibration circuit and voltage measurement temperature effect calibration method of the present invention reduce the direct requirements for the reference voltage generation module itself, thereby reducing the complexity and difficulty of circuit design; at the same time, the temperature effect of the reference voltage generation circuit is compensated in the digital domain, which has low overhead, high stability, and reduces the cost required for high and low temperature compensation adjustments; and only one scan of the entire temperature range is required, further reducing testing costs.

[0109] like Figure 7 As shown, the present invention also provides a battery management system, which includes:

[0110] The present invention includes a voltage measurement temperature effect calibration circuit 1, a battery pack 2 and a control circuit 3.

[0111] like Figure 7 As shown, the voltage measurement temperature effect calibration circuit 1 is connected to the battery pack 2 to sample and calibrate the voltage of at least one cell in the battery pack 2. The specific structure and principle are described above and will not be repeated here.

[0112] like Figure 7 As shown, the control circuit 3 is connected to the output end of the voltage measurement temperature effect calibration circuit 1, and is based on the voltage detection signal D output by the voltage measurement temperature effect calibration circuit 1. OUT_CORRECT Control the charging and discharging of the battery pack 2 and / or protect the safety of the battery pack 2.

[0113] Specifically, the control circuit 3 obtains the calibrated voltage measurement signal (ie, the voltage detection signal D OUT_CORRECT ), based on which the status of the battery pack is grasped and corresponding control signals are generated to control the charging and discharging of the battery pack 2 and / or protect the battery pack 2.

[0114] It should be noted that the battery management system of the present invention can be applied to any occasion where batteries are required, including but not limited to automotive-grade battery management systems.

[0115] The present invention also provides a vehicle, comprising: the battery management system of the present invention; the vehicle includes but is not limited to two-wheeled, three-wheeled and four-wheeled electric vehicles.

[0116] In summary, the present invention provides a voltage measurement temperature effect calibration circuit, method, battery management system and vehicle, including: 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 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 end 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 end of the temperature detection module and the reference voltage generation module, and calculates the compensation parameter based on quadratic fitting of at least three groups of temperature detection signals and corresponding reference voltage data; the temperature effect correction module is connected to the output end 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 and the compensation parameter at the current temperature, 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 invention have lower performance requirements for the reference voltage generation module, eliminating the need for complex circuit design within the analog circuit domain, making the design easier to implement. The requirements for the device temperature coefficient in the process are lowered, allowing the technical solution to be applied to a variety of different process nodes. Digital back-end calibration is performed for errors caused by the reference voltage temperature drift effect, requiring only a single full temperature range scan during chip factory testing, eliminating the need for extensive high and low temperature testing time and effectively saving costs. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial utilization value.

[0117] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A voltage measurement temperature effect calibration circuit, applied to automotive-grade battery management systems, characterized in that: The voltage measurement temperature effect calibration circuit at least includes: Temperature detection module, sampling module, reference voltage generation module, quantization module, compensation parameter calculation module and 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 generating 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 end of the temperature detection module and the reference voltage generation module, and calculates the compensation parameter based on a quadratic fit of at least three sets of temperature detection signals and corresponding reference voltage data; 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 and the compensation parameter at the current temperature, 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 according to claim 1, characterized in that: The temperature detection module includes 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. The quantizer is connected to the output end 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 according to claim 1, wherein: The temperature effect correction module includes 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 includes a non-volatile storage module connected between the output end of the compensation parameter calculation module and the input end of the temperature effect correction module for storing the compensation parameters.

5. A voltage measurement temperature effect calibration method, implemented based on the voltage measurement temperature effect calibration circuit according to any one of claims 1 to 4, characterized in that: The voltage measurement temperature effect calibration method at least includes: S1: Perform a full temperature range scan and record at least three sets of temperature detection signals and reference voltage data corresponding to dispersed temperature points; perform a second-order fitting on the three sets of data to calculate the compensation parameters; S2: When measuring the voltage to be measured, the temperature compensation coefficient at the current temperature is calculated according to the compensation parameter and the temperature detection signal at the current working environment temperature; the voltage to be measured is collected and converted into a digital signal, and the digital signal of the voltage to be measured is corrected based on the temperature compensation coefficient to obtain a voltage detection signal after temperature compensation.

6. The voltage measurement temperature effect calibration method according to claim 5, characterized in that: The second-order fitting method in step S1 includes: S11: Establish a second-order polynomial model that satisfies: 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 2 +bt+c; Wherein, R(t) is the temperature compensation coefficient, a, b, and c are the compensation parameters, and t is the temperature detection signal at the current working environment temperature.

8. The voltage measurement temperature effect calibration method according to claim 7, characterized in that: The voltage detection signal satisfies: D OUT_CORRECT =D OUT ·R(t); Among them, D OUT_CORRECT is the voltage detection signal, D OUT is the digital signal of the voltage to be measured.

9. A battery management system, characterized in that: The battery management system at least includes: A battery pack, a control circuit, and a voltage measurement temperature effect calibration circuit according to any one of claims 1 to 4; The voltage measurement temperature effect calibration circuit is connected to the battery pack to sample and calibrate 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, 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.

10. A vehicle, characterized in that: The vehicle at least includes: the battery management system according to claim 9.

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