BMS controller current sampling circuit

Abstract

The utility model provides a BMS controller current sampling circuit. The BMS controller current sampling circuit comprises a first differential current sampling circuit, a second differential current sampling circuit and a microcontroller MCU. Two input ends of the first differential current sampling circuit are respectively connected with two ends of a battery pack to be sampled, and an output end of the first differential current sampling circuit is connected with a first A / D conversion input end of the MCU; the two input ends of the second differential current sampling circuit are connected with the two ends of the battery pack to be sampled respectively, and the output end of the second differential current sampling circuit is connected with the second A / D conversion input end of the MCU; wherein the differential amplification factor of the first differential current sampling circuit is not equal to the differential amplification factor of the second differential current sampling circuit. According to the utility model, the accuracy of current sampling is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to current sampling technical field, and specifically speaking, relate to a kind of BMS controller current sampling circuit. BACKGROUND

[0002] BMS (Battery Management System) controller, i.e. battery management system controller, is mainly used to monitor and manage the working state of battery pack to ensure that battery pack works in safe and reliable conditions. In order to control the charging and discharging of battery through BMS controller, the current data of battery needs to be collected first.

[0003] In the field of current sampling technology, there is a current data collection method in the prior art, that is, collecting current data through a differential amplification circuit. For example, the Chinese national patent application with publication number CN106646248A discloses a BMS current detection and overcurrent protection circuit, which includes a current sampling module that collects and amplifies the working current on the current sampling resistor and inputs it to the MCU microcontroller unit.

[0004] There is also a current data collection method in the prior art, such as the Chinese national patent with publication number CN221100886U, which discloses a BMS two-way current sampling circuit. It not only measures current through the sampling circuit inside BCC, but also measures current through a differential amplification circuit, with the purpose of improving the reliability and safety of current sampling.

[0005] However, the above-mentioned differential amplification circuit, due to the use of single-range sampling, may cause some small current data to be unable to be collected or the accuracy of collection to be low.

[0006] In order to solve the above problems, people have been seeking an ideal technical solution. SUMMARY

[0007] The utility model aims at the deficiency of prior art, and provides a kind of high-precision BMS controller current sampling circuit.

[0008] In order to achieve the above-mentioned purpose, the utility model provides a kind of BMS controller current sampling circuit, which includes:

[0009] a first differential current sampling circuit, a second differential current sampling circuit and a microcontroller MCU;

[0010] The two input terminals of the first differential current sampling circuit are respectively connected to the two ends of the battery pack to be sampled, and the output terminal of the first differential current sampling circuit is connected to the first A / D conversion input terminal of the microcontroller MCU.

[0011] Two input ends of the second differential current sampling circuit are connected with two ends of the battery group to be sampled respectively, and an output end of the second differential current sampling circuit is connected with a second A / D conversion input end of the micro controller MCU;

[0012] The differential amplification multiple in the first differential current sampling circuit is not equal to the differential amplification multiple of the second differential current sampling circuit.

[0013] The utility model discloses the beneficial effects are:

[0014] The utility model discloses two different amplification multiples of differential current sampling circuit (first differential current sampling circuit and second differential current sampling circuit), when sampling current is little, adopt the differential current sampling circuit of amplification multiple, when sampling current is big, adopt the differential current sampling circuit of amplification multiple little, to improve the precision of whole current sampling interval. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a circuit principle schematic view of BMS controller current sampling circuit. DETAILED DESCRIPTION

[0016] The technical scheme of the utility model will be described further in detail through specific implementation ways.

[0017] The terms "first", "second", "third", "fourth" and the like in the description, claims, and drawings of the application refer to such objects as distinguish from one another, and do not necessarily have to describe a particular sequential or chronological order, unless otherwise indicated. It is to be understood that the terms so used are interchangeable under appropriate circumstances and are merely employed to distinguish one object from another.

[0018] Embodiment 1

[0019] As shown in the accompanying drawings, Figure 1 The embodiment gives a specific implementation of the current sampling circuit based on the BMS controller.

[0020] A BMS controller current sampling circuit, comprising a first differential current sampling circuit, a second differential current sampling circuit and a micro controller MCU;

[0021] Two input ends of the first differential current sampling circuit are connected with two ends of the battery group to be sampled respectively, and an output end of the first differential current sampling circuit is connected with a first A / D conversion input end (Current1) of the micro controller MCU;

[0022] The two input ends of the second differential current sampling circuit are connected with the two ends of the battery to be sampled respectively, and the output end of the second differential current sampling circuit is connected with the second A / D conversion input end (Current2) of the microcontroller MCU.

[0023] The differential amplification multiple in the first differential current sampling circuit is not equal to the differential amplification multiple of the second differential current sampling circuit. The differential current sampling circuit comprises a differential amplification circuit.

[0024] The reason for setting the two differential current sampling circuits with different differential amplification multiples is that: if only one differential current sampling circuit is used to collect the current data of the battery, the differential amplification multiple of the differential current sampling circuit is fixed, when the current of the battery is too small and the differential amplification multiple is too small, the accuracy of the current data of the battery obtained through the differential current sampling circuit and the MCU is low, and thus the control of the battery according to the collected current data may be wrong, or the current data of the battery may not be collected through the differential current sampling circuit and the MCU, and thus the control of the battery is wrong.

[0025] Therefore, the utility model sets two differential current sampling circuits to collect the current data of the battery, and the differential amplification multiples of the two differential current sampling circuits are different, when the current of the battery is large, the current data can be collected through the differential current sampling circuit with a small differential amplification multiple to solve the above problem of exceeding the range, when the current of the battery is small, the current data can be collected through the differential current sampling circuit with a large differential amplification multiple to improve the accuracy of the collected current data.

[0026] In some embodiments, for a certain moment, if the current data of the battery can be collected through the two differential current sampling circuits, the current data collected through any one of the differential current sampling circuits can be selected as the basis for subsequent judgment processing.

[0027] Embodiment 2

[0028] The difference between the embodiment and the embodiment 1 is that a specific implementation scheme of the first differential current sampling circuit is provided.

[0029] The first differential current sampling circuit comprises a resistor R1, a resistor R2, a resistor R4, a resistor R5 and an operational amplifier U1A.

[0030] The inverting input end of the operational amplifier U1A is connected in series with the resistor R2 as the first input end of the first differential current sampling circuit, the non-inverting input end of the operational amplifier U1A is connected in series with the resistor R4 as the second input end of the first differential current sampling circuit, and the output end of the operational amplifier U1A is used as the output end of the first differential current sampling circuit.

[0031] The resistor R1 is connected in parallel between the inverting input end and the output end of the operational amplifier U1A.

[0032] The first reference power supply is connected to the non-inverting input end of the operational amplifier U1A through the resistor R5.

[0033] It should be noted that the resistance values in the first differential current sampling circuit should be properly selected to accurately amplify the weak voltage signal by a certain multiple, and the resistor R2 and the resistor R4 are equal to ensure that the non-inverting input and the inverting input are balanced and the differential mode interference is reduced.

[0034] The resistor R1 and the resistor R5 are equal. The differential amplification multiple in the first differential current sampling circuit is R5 / R4.

[0035] In some embodiments, the model of the MCU is STM32F103VCT6, the reference voltage is 3.3 volts, and the voltage of the first reference power supply can be 1.65 volts.

[0036] In some embodiments, the first differential current sampling circuit further comprises a capacitor C1, wherein the capacitor C1 is connected in parallel with the resistor R1. It should be noted that the resistor R1 and the capacitor C1 form a negative feedback network, wherein the capacitor C1 plays a compensating role to improve the amplification multiple of the signal.

[0037] In some embodiments, the first differential current sampling circuit further comprises a capacitor C2 and a capacitor C5, wherein one end of the capacitor C2 is connected to the inverting input end of the operational amplifier U1A, and the other end is grounded; one end of the capacitor C5 is connected to the non-inverting input end of the operational amplifier U1A, and the other end is grounded. The functions of the capacitor C2 and the capacitor C5 include eliminating high-frequency components in the circuit.

[0038] Embodiment 3

[0039] The difference between this embodiment and embodiment 1 is that a specific implementation of a second differential current sampling circuit is provided.

[0040] The second differential current sampling circuit comprises a resistor R6, a resistor R8, a resistor R10, a resistor R11 and an operational amplifier U1B.

[0041] The inverting input terminal of the operational amplifier U1B is connected in series with the resistor R8 as the first input terminal of the second differential current sampling circuit, the non-inverting input terminal of the operational amplifier U1B is connected in series with the resistor R10 as the second input terminal of the second differential current sampling circuit, and the output terminal of the operational amplifier U1B is the output terminal of the second differential current sampling circuit.

[0042] The resistor R6 is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier U1B.

[0043] The second reference power supply is connected to the non-inverting input terminal of the operational amplifier U1B through the resistor R11.

[0044] It should be noted that the resistor R8 is equal to the resistor R10, the resistor R6 is equal to the resistor R11, and the amplification factor of the differential amplification circuit of the second differential current sampling circuit is R11 / R10.

[0045] In some embodiments, the voltage of the second reference power supply can be 1.65 volts.

[0046] In some embodiments, the second differential current sampling circuit further comprises a capacitor C6, wherein the capacitor C6 is connected in parallel with the resistor R6.

[0047] In some embodiments, the second differential current sampling circuit further comprises a capacitor C7 and a capacitor C10, wherein one end of the capacitor C7 is connected to the inverting input terminal of the operational amplifier U1B, and the other end is grounded; and one end of the capacitor C10 is connected to the non-inverting input terminal of the operational amplifier U1B, and the other end is grounded.

[0048] The functions of the capacitors C6, C7 and C10 are not repeated here.

[0049] Embodiment 4

[0050] The difference between this embodiment and any one of embodiments 1-3 is that a specific implementation of the filter circuit is provided.

[0051] As shown in Figure 1 In order to make the current input to the MCU more stable, a first filter circuit is provided between the output terminal of the first differential current sampling circuit and the first A / D conversion input terminal, the first filter circuit comprising a magnetic bead L1 and a first π-shaped RC filter circuit connected in series, the first π-shaped RC filter circuit comprising a resistor R3, a capacitor C3 and a capacitor C4; a second filter circuit is provided between the output terminal of the second differential current sampling circuit and the second A / D conversion input terminal, the second filter circuit comprising a magnetic bead L2 and a second π-shaped RC filter circuit connected in series, the second π-shaped RC filter circuit comprising a resistor R9, a capacitor C8 and a capacitor C9.

[0052] Example 5

[0053] The difference between this embodiment and any one of Examples 1-3 is that the BMS controller current sampling circuit further comprises a differential sampling shunt resistor R7; the differential sampling shunt resistor R7 is connected in parallel across the battery pack to be sampled. One end of the differential sampling shunt resistor R7 can be grounded.

[0054] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can still be modified or some technical features can be replaced by equivalent ones; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range claimed by the present application.

Claims

1. A BMS controller current sampling circuit, characterized in that: The first differential current sampling circuit, the second differential current sampling circuit and the microcontroller MCU are included. Two input terminals of the first differential current sampling circuit are connected with two terminals of the battery to be sampled respectively, and an output terminal of the first differential current sampling circuit is connected with a first A / D conversion input terminal of the microcontroller MCU. Two input terminals of the second differential current sampling circuit are connected with two terminals of the battery to be sampled respectively, and an output terminal of the second differential current sampling circuit is connected with a second A / D conversion input terminal of the microcontroller MCU. The differential amplification multiple in the first differential current sampling circuit is not equal to the differential amplification multiple of the second differential current sampling circuit.

2. The BMS controller current sampling circuit of claim 1, wherein, The first differential current sampling circuit includes resistors R1, R2, R4, R5 and an operational amplifier U1A. The non-inverting input terminal of the operational amplifier U1A is connected with the resistor R2 in series as the first input terminal of the first differential current sampling circuit, the inverting input terminal of the operational amplifier U1A is connected with the resistor R4 in series as the second input terminal of the first differential current sampling circuit, and the output terminal of the operational amplifier U1A is connected as the output terminal of the first differential current sampling circuit. The resistor R1 is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier U1A. A first reference power supply is connected to the non-inverting input terminal of the operational amplifier U1A through the resistor R5.

3. The BMS controller current sampling circuit of claim 2, wherein, The first differential current sampling circuit further includes a capacitor C1. The capacitor C1 is connected in parallel with the resistor R1.

4. The BMS controller current sampling circuit of claim 2, wherein, The first differential current sampling circuit further includes capacitors C2 and C5. One end of the capacitor C2 is connected with the inverting input terminal of the operational amplifier U1A, and the other end is grounded; one end of the capacitor C5 is connected with the non-inverting input terminal of the operational amplifier U1A, and the other end is grounded.

5. The BMS controller current sampling circuit of claim 1, wherein, The second differential current sampling circuit includes resistors R6, R8, R10, R11 and an operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected with the resistor R8 in series as the first input terminal of the second differential current sampling circuit, the inverting input terminal of the operational amplifier U1B is connected with the resistor R10 in series as the second input terminal of the second differential current sampling circuit, and the output terminal of the operational amplifier U1B is connected as the output terminal of the second differential current sampling circuit. The resistor R6 is connected in parallel between the inverting input terminal and the output terminal of the operational amplifier U1B. A second reference power supply is connected to the non-inverting input terminal of the operational amplifier U1B through the resistor R11.

6. The BMS controller current sampling circuit of claim 5, wherein, The second differential current sampling circuit further includes a capacitor C6. The capacitor C6 is connected in parallel with the resistor R6.

7. The BMS controller current sampling circuit of claim 5, wherein, The second differential current sampling circuit further includes capacitors C7 and C10. One end of the capacitor C7 is connected with the inverting input terminal of the operational amplifier U1B, and the other end is grounded; one end of the capacitor C10 is connected with the non-inverting input terminal of the operational amplifier U1B, and the other end is grounded.

8. The BMS controller current sampling circuit of claim 1 or 2, wherein, A first filter circuit is arranged between the output end of the first differential current sampling circuit and the first A / D conversion input end, and the first filter circuit comprises a magnetic bead L1 and a first π-shaped RC filter circuit connected in series.

9. The BMS controller current sampling circuit of claim 1 or 5, wherein, A second filter circuit is arranged between the output end of the second differential current sampling circuit and the second A / D conversion input end, and the second filter circuit comprises a magnetic bead L2 and a second π-shaped RC filter circuit connected in series.

10. The BMS controller current sampling circuit of claim 1, wherein: The BMS controller current sampling circuit further comprises a differential sampling shunt resistor R7, which is connected in parallel across the battery pack to be sampled.

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