High-precision voltage sampling circuit and energy storage system

Abstract

The utility model discloses a high precision voltage sampling circuit and an energy storage system, the high precision voltage sampling circuit comprises a reference sampling circuit and a precision sampling circuit, the amplification factor of the reference sampling circuit is the same as that of the precision sampling circuit, and the amplification factor of the precision sampling circuit is the same as that of the reference sampling circuit. The sampling rate of the reference sampling circuit is higher than that of the precision sampling circuit; the reference sampling circuit is used for carrying out primary sampling and determining a reference voltage range, the precise sampling circuit is used for carrying out secondary sampling and obtaining a sampling voltage, and the sampling voltage is within the reference voltage range. Compared with the prior art, the sampling precision of the energy storage system can be effectively improved, a more accurate sampling result can be obtained, the operation of the energy storage system is more stable, and the purpose of accurate control is achieved.

Description

Technical Field

[0001] The utility model relates to an energy storage system, in particular to a high-precision voltage sampling circuit and an energy storage system. Background Art

[0002] In energy storage systems, DC-DC (Direct-Channel-Driven-Chip) circuits require voltage or current sampling to protect the system. However, factors such as sampling resistor accuracy, op amp zero-drift characteristics, and soldering errors between the sampling resistor and the PCB can lead to significant errors in the ADC sampled values, impacting system stability and performance.

[0003] Therefore, how to design a high-precision voltage sampling circuit and energy storage system is a technical problem that needs to be solved urgently in the industry. Utility Model Content

[0004] In view of the problem in the prior art that a large error may occur when an energy storage system samples voltage or current, the utility model proposes a high-precision voltage sampling circuit and an energy storage system.

[0005] The technical solution of the utility model is to propose a high-precision voltage sampling circuit, comprising a reference sampling circuit and a precision sampling circuit, wherein the reference sampling circuit has the same amplification factor as the precision sampling circuit, and the sampling rate of the reference sampling circuit is higher than that of the precision sampling circuit;

[0006] The reference sampling circuit is used for primary sampling and determining a reference voltage range, and the precision sampling circuit is used for secondary sampling and obtaining a sampled voltage, wherein the sampled voltage is within the reference voltage range.

[0007] Furthermore, the reference sampling circuit is an amplifier circuit composed of an amplifier and a plurality of voltage-dividing resistors;

[0008] The reference voltage range is determined according to a reference value output by the reference sampling circuit for sampling the voltage to be measured, and the amplification factor of the reference value compared to the voltage to be measured is set by the voltage dividing resistor.

[0009] Furthermore, the reference sampling circuit includes: a first amplifier U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a resistor R5;

[0010] The first input terminal of the first amplifier U1 is connected in series with the resistor R1 and then connected to the first terminal of the sampling resistor. The second input terminal of the first amplifier U1 is connected in series with the resistor R2 and then connected to the second terminal of the sampling resistor. The output terminal of the first amplifier U1 is connected in series with the resistor R5 and then outputs the reference value.

[0011] One end of the resistor R4 is connected to a 0.5V voltage, and the other end is connected between the resistor R1 and the first input terminal of the first amplifier U1. A preset voltage is also introduced on the side of the resistor R4 connected to the 0.5V voltage.

[0012] One end of the resistor R3 is connected between the resistor R2 and the second input end of the first amplifier U1 , and the other end is connected between the resistor R5 and the output end of the first amplifier U1 .

[0013] Furthermore, the calculation model satisfied by the reference value and the voltage to be measured is:

[0014] Vref=R3 / R2*Vsense+0.5;

[0015] Wherein, Vref is the reference value, Vsense is the voltage to be measured, R2 is the resistance value of the resistor R2, and R3 is the resistance value of the resistor R3.

[0016] Furthermore, the reference voltage range is set to (0.9*Vref, 1.1*Vref);

[0017] Wherein, Vref is the reference value.

[0018] Furthermore, the precision sampling circuit is an amplifier circuit composed of three amplifiers and a plurality of voltage-dividing resistors;

[0019] The amplification factor of the sampling value output by the precision sampling circuit compared to the voltage to be measured is set by the voltage dividing resistor.

[0020] Furthermore, the precision sampling circuit includes: a second amplifier U2, a third amplifier U3, a fourth amplifier U4, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a resistor R11;

[0021] One end of the resistor R6 is connected to the output end of the second amplifier U2, and the other end of the resistor R6 is connected to the output end of the third amplifier U3 after being connected in series with the resistor R7 and the resistor R8;

[0022] The first input terminal of the second amplifier U2 is connected to the first terminal of the sampling resistor, the second input terminal of the second amplifier U2 is connected between the resistor R6 and the resistor R7, and the output terminal of the second amplifier U2 is connected to the output terminal of the fourth amplifier U4 after being connected in series with the resistor R9 and the resistor R11;

[0023] The first input end of the third amplifier U3 is connected between the resistor R7 and the resistor R8, the second input end of the third amplifier U3 is connected to the second end of the sampling resistor, and the output end of the third amplifier U3 is connected in series with the resistor R10 and the resistor R12 and then grounded;

[0024] The first input terminal of the fourth amplifier U4 is connected between the resistor R9 and the resistor R11 , the second input terminal of the fourth amplifier U4 is connected between the resistor R10 and the resistor R12 , and the output terminal of the fourth amplifier U4 is used to output the sampling voltage.

[0025] Furthermore, the calculation model satisfied by the sampled voltage and the voltage to be measured is:

[0026] Vout=(R11 / R9)*[(R6+R8) / R7*Vsense]+R12 / R10*Vsense;

[0027] Among them, Vout is the sampling voltage, Vsense is the voltage to be measured, R6 is the resistance value of the resistor R6, R7 is the resistance value of the resistor R7, R8 is the resistance value of the resistor R8, R9 is the resistance value of the resistor R9, R10 is the resistance value of the resistor R10, R11 is the resistance value of the resistor R11, and R12 is the resistance value of the resistor R12.

[0028] Furthermore, the final sampling value of the high-precision voltage sampling circuit is:

[0029]

[0030] Wherein, V is the sampling value, N is the number of samplings, Vk is the filtered value of the k-th sampling voltage, Vmax is the maximum value of the filtered value of the sampling voltage in N samplings, and Vmin is the minimum value of the filtered value of the sampling voltage in N samplings.

[0031] The utility model also proposes an energy storage system, which has the above-mentioned high-precision voltage sampling circuit.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] The utility model performs two samplings through a reference sampling circuit and a precision sampling circuit. The first sampling is coarse sampling through the reference sampling circuit to complete the acquisition of the reference voltage range. The second sampling is precision sampling. Whether the result of the second sampling is valid is judged according to whether the result of the second sampling falls within the reference voltage range. The accuracy of sampling is improved by the two sampling results, thereby achieving the purpose of precise control. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 This is a block diagram of the overall principle of the utility model;

[0036] Figure 2 This is a circuit connection diagram of the reference sampling circuit in the present utility model;

[0037] Figure 3 This is a circuit connection diagram of the precision sampling circuit in the present utility model;

[0038] Figure 4 This is the overall workflow diagram of the utility model. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Thus, a feature indicated in this specification is intended to illustrate one of the features of one embodiment of the present invention, rather than implying that every embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although certain features can be combined together to illustrate possible system designs, these features can also be used in other, not explicitly described, combinations. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0041] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0042] In energy storage systems, DC-DC (Direct-Channel-Driven-Chip) circuits require voltage or current sampling to protect the system. However, factors such as sampling resistor accuracy, op amp zero-drift characteristics, and soldering errors between the sampling resistor and the PCB can lead to significant errors in the ADC sampled values, impacting system stability and performance.

[0043] In response to the above problems, the technical solution of the present invention is to set up a reference sampling circuit and a precision sampling circuit, and perform two samplings through the reference sampling circuit and the precision sampling circuit. The first sampling is coarse sampling through the reference sampling circuit to complete the acquisition of the reference voltage range. The second sampling is precision sampling. Whether the result of the second sampling is valid is judged based on whether the result of the second sampling falls within the reference voltage range. The accuracy of sampling is improved by the two sampling results, thereby achieving the purpose of precise control.

[0044] Based on the above ideas, the high-precision voltage sampling circuit proposed in the present invention includes a reference sampling circuit and a precision sampling circuit. The reference sampling circuit and the precision sampling circuit have the same amplification factor, and the sampling rate of the reference sampling circuit is higher than that of the precision sampling circuit.

[0045] The reference sampling circuit is used for primary sampling and determining the reference voltage range, and the precision sampling circuit is used for secondary sampling and obtaining the sampling voltage, and the sampling voltage is within the reference voltage range.

[0046] Here, setting the magnification of the reference sampling circuit and the precision sampling circuit to be the same is a necessary prerequisite for implementing the above solution. If the magnification is different, it cannot be guaranteed that the results of the two samplings are close.

[0047] The sampling rate of the reference sampling circuit is set higher than that of the precision sampling circuit because the reference sampling circuit is required to perform a sampling action first, and then determine a reference voltage range based on the sampling result of the reference sampling circuit for the precision sampling circuit to perform a second sampling action;

[0048] Here, the sampling accuracy of the precision sampling circuit is higher than that of the reference sampling circuit, and is used for further precise detection. The reference sampling circuit is used to set the reference voltage range. If the sampling result of the precision sampling circuit is not within the reference voltage range, it means that the sampling result is incorrect and needs to be re-sampling. Otherwise, the sampling result is considered valid. The utility model also performs multiple sampling to further improve the sampling accuracy.

[0049] like Figure 1 As shown, it is a logic block diagram of the entire utility model. The utility model mainly includes two parts: a precision sampling circuit and a reference sampling circuit. In addition to connecting the precision sampling circuit and the reference sampling circuit, the ADC channel of the chip also samples a voltage of 0.5V.

[0050] The reference sampling circuit is used to make the currently sampled voltage fall into a suitable voltage range, that is, the reference voltage range mentioned above. The precision sampling circuit amplifies and samples the voltage on the sampling resistor.

[0051] The sampling resistors in this utility model should be high-precision sampling resistors, and during operation, considering temperature factors, the input of each amplifier should not be greater than its supply voltage. If the sampled value exceeds the reference voltage range during the sampling process, it needs to be properly eliminated.

[0052] The utility model can obtain more accurate sampling results through the above two samplings, making the operation of the energy storage system more stable.

[0053] The following describes the settings of the reference sampling circuit and the precision sampling circuit in the present invention. For the reference sampling circuit:

[0054] The reference sampling circuit is an amplifier circuit composed of an amplifier and a plurality of voltage-dividing resistors;

[0055] The above-mentioned reference voltage range is determined according to the reference value output by the reference sampling circuit for sampling the voltage to be measured, and the amplification factor of the reference value compared to the voltage to be measured is set by the voltage divider resistor.

[0056] For details, see Figure 2 , the reference sampling circuit in the utility model includes: a first amplifier U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a resistor R5;

[0057] A first input terminal of the first amplifier U1 is connected in series with a resistor R1 and then to the first terminal of the sampling resistor. A second input terminal of the first amplifier U1 is connected in series with a resistor R2 and then to the second terminal of the sampling resistor. An output terminal of the first amplifier U1 is connected in series with a resistor R5 and then to output a reference value.

[0058] One end of the resistor R4 is connected to a 0.5V voltage, and the other end is connected between the resistor R1 and the first input terminal of the first amplifier U1. A preset voltage is also introduced to the side of the resistor R4 connected to the 0.5V voltage.

[0059] One end of the resistor R3 is connected between the resistor R2 and the second input end of the first amplifier U1 , and the other end is connected between the resistor R5 and the output end of the first amplifier U1 .

[0060] Here, the resistors R1, R2, R3, and R4 are set as the above-mentioned voltage divider resistors, the resistor Rsense is a sampling resistor, the voltage on the sampling resistor Rsense is the voltage to be measured Vsense, the first amplifier U1 is also the above-mentioned amplifier, and the preset voltage is Figure 1 and Figure 2 The voltage V1 in.

[0061] In the present invention, the first input terminal of the first amplifier U1 is connected to the first terminal of the sampling resistor Rsense via the resistor R1, and the second input terminal of the first amplifier U1 is connected to the second terminal of the sampling resistor Rsense via the resistor R2. According to the working principle of the first amplifier U1, it can be calculated that the relationship between the output voltage of the amplifier U1 and the voltage to be measured on the sampling resistor Rsense satisfies:

[0062] Vref=R3 / R2*Vsense+0.5;

[0063] Wherein, Vref is the reference value, Vsense is the voltage to be measured, R2 is the resistance value of resistor R2, and R3 is the resistance value of resistor R3.

[0064] In the above embodiment, it is preferred that R1 = R2 and R3 = R4 be satisfied, that is, the resistance values ​​of the resistors R1 and R2 are the same, and the resistance values ​​of the resistors R3 and R4 are the same.

[0065] It can be seen from the above calculation model that the magnitude of the reference value is determined by the resistance values ​​of the resistors R3 and R2 , and therefore the amplification factor of the reference sampling circuit can be set by setting the resistance values ​​of the resistors R3 and R2 .

[0066] After sampling and obtaining the reference value through the reference sampling circuit, the corresponding reference voltage range can be set according to the reference value. In the present invention, the reference voltage range is set to a deviation of 10% above and below the above reference value, that is, (0.9*Vref, 1.1*Vref);

[0067] Here, the reference voltage range is determined according to the actual required sampling accuracy. In other embodiments of the present invention, the reference voltage range may also be set to a reference value with a deviation of 3% above and below, that is, (0.97*Vref, 1.03*Vref);

[0068] After obtaining the above reference voltage range, a second sampling is required through a precision sampling circuit. The following describes the settings of the precision sampling circuit:

[0069] The precision sampling circuit in the utility model is an amplifier circuit composed of three amplifiers and multiple voltage-dividing resistors;

[0070] The amplification factor of the sampling value output by the precision sampling circuit compared to the voltage to be measured is set by the above-mentioned voltage divider resistor.

[0071] See Figure 3 , the precision sampling circuit in the utility model includes: a second amplifier U2, a third amplifier U3, a fourth amplifier U4, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a resistor R11;

[0072] One end of the resistor R6 is connected to the output end of the second amplifier U2, and the other end of the resistor R6 is connected in series with the resistor R7 and the resistor R8 and then connected to the output end of the third amplifier U3;

[0073] A first input terminal of the second amplifier U2 is connected to a first terminal of the sampling resistor, a second input terminal of the second amplifier U2 is connected between the resistor R6 and the resistor R7, and an output terminal of the second amplifier U2 is connected to an output terminal of the fourth amplifier U4 after being connected in series with the resistor R9 and the resistor R11;

[0074] A first input terminal of the third amplifier U3 is connected between the resistor R7 and the resistor R8, a second input terminal of the third amplifier U3 is connected to the second end of the sampling resistor, and an output terminal of the third amplifier U3 is connected in series with the resistor R10 and the resistor R12 and then grounded;

[0075] A first input terminal of the fourth amplifier U4 is connected between the resistor R9 and the resistor R11 , a second input terminal of the fourth amplifier U4 is connected between the resistor R10 and the resistor R12 , and an output terminal of the fourth amplifier U4 is used to output a sampling voltage.

[0076] The second amplifier U2 is used to amplify the voltage at the first end of the sampling resistor Rsense. Figure 3 As shown, its output voltage is Va;

[0077] The third amplifier U3 is used to amplify the voltage at the second end of the sampling resistor Rsense. Figure 3 As shown, its output voltage is Vb;

[0078] The fourth amplifier U4 is used to amplify the voltage Va output by the second amplifier U2 and the voltage Vb output by the third amplifier U3, and output the final sampling voltage, such as Figure 3 As shown, its output voltage is Vout;

[0079] The voltage divider resistors in the above-mentioned tight sampling circuit mainly refer to resistors R6, R7, R8, R9, R10, R11, and R12, and the amplifiers mainly refer to the second amplifier U2, the third amplifier U3, and the fourth amplifier U4.

[0080] In order to achieve accurate sampling of voltage in the present invention, R6=R8, R9=R10, and R11=R12 are set, that is, the resistance value of resistor R6 is the same as the resistance value of resistor R8, the resistance value of resistor R9 is the same as the resistance value of resistor R10, and the resistance value of resistor R11 is the same as the resistance value of resistor R12;

[0081] Here, the voltage output by the second amplifier U2 is set to Va, and the voltage output by the third amplifier U3 is set to Vb;

[0082] According to the working principle of the amplifier, the calculation model satisfied by the output voltage Va of the second amplifier U2 is:

[0083]

[0084] The calculation model satisfied by the output voltage Vb of the third amplifier U3 is:

[0085] Vb=Vsense;

[0086] The output voltage of the precision sampling circuit, that is, the sampling value is the calculation model of the output voltage of the fourth amplifier U4:

[0087]

[0088] Combining the above three calculation models, we can get the calculation model that the sampling voltage and the voltage to be measured satisfy:

[0089] Vout=(R11 / R9)*[(R6+R8) / R7*Vsense]+R12 / R10*Vsense;

[0090] Among them, Vout is the sampling voltage, Vsense is the voltage to be measured, R6 is the resistance value of resistor R6, R7 is the resistance value of resistor R7, R8 is the resistance value of resistor R8, R9 is the resistance value of resistor R9, R10 is the resistance value of resistor R10, R11 is the resistance value of resistor R11, and R12 is the resistance value of resistor R12.

[0091] Since R6=R8, R9=R10, and R11=R12 are set in the present invention, the above calculation model can also be optimized as follows:

[0092]

[0093] The present invention will be described below with reference to specific examples:

[0094] The total battery voltage of the energy storage system set by the utility model is 500V, the rated current is 50A, the sampling resistance is 1mΩ (1%), and the voltage on the sampling resistance is 0.05V;

[0095] In order to maximize the sampling accuracy, the present invention sets R3 / R2=36 in the above-mentioned reference sampling circuit, thereby obtaining a reference voltage of Vref=36Vsense+0.5;

[0096] The voltage range of the chip terminal voltage sampling (that is, the reference voltage range mentioned above) is Vref±10%Vref;

[0097] In the precision sampling circuit, the amplification factor is the same as that in the reference sampling circuit, so the sampling circuit can perform voltage calibration and calculation within the reference voltage range;

[0098] First determine whether the condition 0.90*Vref<Vout+V1<Vref*1.10 is met;

[0099] If the conditions are met, ΔU = Vout - (Vref - V1) can be calculated;

[0100] Finally, the corrected sampling value U=Vout+ΔU / 2 is obtained;

[0101] If 0.9*Vref<Vout+V1<Vref*1.1 is not satisfied, the above sampled voltage is discarded and resampled.

[0102] In order to further improve the sampling accuracy, the present invention needs to perform multiple samplings, and the final sampling value satisfies the calculation model:

[0103]

[0104] Wherein, V is the sampling value, N is the number of samplings, Vk is the filtered value of the k-th sampling voltage, Vmax is the maximum value of the filtered value of the sampling voltage in N samplings, and Vmin is the minimum value of the filtered value of the sampling voltage in N samplings.

[0105] See Figure 4 , which is the overall flow chart of the voltage sampling of the utility model, which includes the following steps:

[0106] When starting sampling, wait for the energy storage system, clock, etc. to initialize;

[0107] Then set the sampling times to zero (multiple samplings will be performed later, and the sampling times need to be counted, so the sampling times need to be set to zero in advance);

[0108] Then, a first coarse sampling is performed, wherein the first sampling is performed by a reference sampling circuit, and a reference voltage range is obtained after the reference sampling circuit samples the voltage;

[0109] Then, a second precision sampling is performed continuously for multiple times, and the second sampling is performed by a precision sampling circuit;

[0110] After completing a sampling of a precision circuit, first determine whether the number of sampling times reaches the preset number, where the preset number is set to N;

[0111] If the preset number of times is reached, the sampling stops, otherwise AD acquisition is performed;

[0112] Then perform numerical filtering and data storage, that is, perform the above-mentioned calculation steps of the final sample value;

[0113] After completing the above steps, add 1 to the current sampling number and re-judge whether the sampling number has reached the preset number;

[0114] If the preset number of times is reached, the sampling stops; otherwise, the above process is repeated.

[0115] The utility model also proposes an energy storage system, which has the above-mentioned high-precision voltage sampling circuit.

[0116] Compared with the prior art, the present invention has at least the following beneficial effects:

[0117] The utility model performs two samplings through a reference sampling circuit and a precision sampling circuit. The first sampling is coarse sampling through the reference sampling circuit to complete the acquisition of the reference voltage range. The second sampling is precision sampling. Whether the result of the second sampling is valid is judged according to whether the result of the second sampling falls within the reference voltage range. The accuracy of sampling is improved by the two sampling results, thereby achieving the purpose of precise control.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-precision voltage sampling circuit, characterized in that: The device comprises a reference sampling circuit and a precision sampling circuit, wherein the reference sampling circuit and the precision sampling circuit have the same amplification factor, and the sampling rate of the reference sampling circuit is higher than that of the precision sampling circuit; The reference sampling circuit is used for primary sampling and determining a reference voltage range, and the precision sampling circuit is used for secondary sampling and obtaining a sampled voltage, wherein the sampled voltage is within the reference voltage range.

2. The high-precision voltage sampling circuit according to claim 1, characterized in that: The reference sampling circuit is an amplifier circuit composed of an amplifier and a plurality of voltage-dividing resistors; The reference voltage range is determined according to a reference value output by the reference sampling circuit for sampling the voltage to be measured, and the amplification factor of the reference value compared to the voltage to be measured is set by the voltage dividing resistor.

3. The high-precision voltage sampling circuit according to claim 2, characterized in that: The reference sampling circuit includes: a first amplifier U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a resistor R5; The first input terminal of the first amplifier U1 is connected in series with the resistor R1 and then connected to the first terminal of the sampling resistor. The second input terminal of the first amplifier U1 is connected in series with the resistor R2 and then connected to the second terminal of the sampling resistor. The output terminal of the first amplifier U1 is connected in series with the resistor R5 and then outputs the reference value. One end of the resistor R4 is connected to a 0.5V voltage, and the other end is connected between the resistor R1 and the first input terminal of the first amplifier U1. A preset voltage is also introduced on the side of the resistor R4 connected to the 0.5V voltage. One end of the resistor R3 is connected between the resistor R2 and the second input end of the first amplifier U1 , and the other end is connected between the resistor R5 and the output end of the first amplifier U1 .

4. The high-precision voltage sampling circuit according to claim 3, characterized in that: The calculation model that the reference value and the voltage to be measured satisfy is: Vref=R3 / R2*Vsense+0.5; Wherein, Vref is the reference value, Vsense is the voltage to be measured, R2 is the resistance value of the resistor R2, and R3 is the resistance value of the resistor R3.

5. The high-precision voltage sampling circuit according to claim 3, characterized in that: The reference voltage range is set to (0.9*Vref, 1.1*Vref); Wherein, Vref is the reference value.

6. The high-precision voltage sampling circuit according to claim 2, characterized in that: The precision sampling circuit is an amplifier circuit composed of three amplifiers and a plurality of voltage-dividing resistors; The amplification factor of the sampling value output by the precision sampling circuit compared to the voltage to be measured is set by the voltage dividing resistor.

7. The high-precision voltage sampling circuit according to claim 6, characterized in that: The precision sampling circuit includes: a second amplifier U2, a third amplifier U3, a fourth amplifier U4, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a resistor R11; One end of the resistor R6 is connected to the output end of the second amplifier U2, and the other end of the resistor R6 is connected to the output end of the third amplifier U3 after being connected in series with the resistor R7 and the resistor R8; The first input terminal of the second amplifier U2 is connected to the first terminal of the sampling resistor, the second input terminal of the second amplifier U2 is connected between the resistor R6 and the resistor R7, and the output terminal of the second amplifier U2 is connected to the output terminal of the fourth amplifier U4 after being connected in series with the resistor R9 and the resistor R11; The first input end of the third amplifier U3 is connected between the resistor R7 and the resistor R8, the second input end of the third amplifier U3 is connected to the second end of the sampling resistor, and the output end of the third amplifier U3 is connected in series with the resistor R10 and the resistor R12 and then grounded; The first input terminal of the fourth amplifier U4 is connected between the resistor R9 and the resistor R11 , the second input terminal of the fourth amplifier U4 is connected between the resistor R10 and the resistor R12 , and the output terminal of the fourth amplifier U4 is used to output the sampling voltage.

8. The high-precision voltage sampling circuit according to claim 7, characterized in that: The calculation model satisfied by the sampled voltage and the voltage to be measured is: Vout=(R11 / R9)*[(R6+R8) / R7*Vsense]+R12 / R10*Vsense; Among them, Vout is the sampling voltage, Vsense is the voltage to be measured, R6 is the resistance value of the resistor R6, R7 is the resistance value of the resistor R7, R8 is the resistance value of the resistor R8, R9 is the resistance value of the resistor R9, R10 is the resistance value of the resistor R10, R11 is the resistance value of the resistor R11, and R12 is the resistance value of the resistor R12.

9. The high-precision voltage sampling circuit according to claim 1, characterized in that: The final sampling value of the high-precision voltage sampling circuit is: Wherein, V is the sampling value, N is the number of samplings, Vk is the filtered value of the k-th sampling voltage, Vmax is the maximum value of the filtered value of the sampling voltage in N samplings, and Vmin is the minimum value of the filtered value of the sampling voltage in N samplings.

10. An energy storage system, characterized in that: A high-precision voltage sampling circuit according to any one of claims 1 to 9.

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