Power supply protection circuit, sampling circuit and battery management system

Abstract

The utility model provides a power supply protection circuit, a sampling circuit and a battery management system. The power supply protection circuit comprises an interference suppression sub-circuit, a first filtering sub-circuit and a second filtering sub-circuit. The interference suppression sub-circuit is respectively connected with the battery module, the first filtering sub-circuit, the second filtering sub-circuit and a ground end, the first filtering sub-circuit is connected with a first power supply pin of the AFE chip, and the second filtering sub-circuit is connected with a second power supply pin of the AEF chip. According to the scheme provided by the utility model, the interference suppression sub-circuit can be used for filtering and suppressing interference signals of a ground wire and offsetting differential mode interference, and the first filtering sub-circuit and the second filtering sub-circuit are matched, so that clutter and noise interference in a power supply loop where the battery module is connected with the AFE chip can be filtered, the anti-interference capability of an AFE sampling power supply part is improved, and the reliability of the AFE sampling power supply part is improved. The stability of an AFE sampling power supply part is improved, and the problems that the power supply part is easily influenced by total voltage fluctuation and the stability is poor in an AFE sampling link are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply protection, and in particular to a power supply protection circuit, a sampling circuit and a battery management system. Background Art

[0002] The AFE (Analog Front End) chip is an indispensable part of the sampling function in the battery management system, and is mainly used for battery cell voltage collection, module temperature collection and balancing functions.

[0003] In the related art, since the AFE chip mainly draws power from the battery module, when the series or parallel relationship of the battery module changes, the power supply voltage fluctuates, and the power supply circuit of the AFE chip is prone to oscillation, causing the AFE chip to have invalid sampling within a certain period of time, thereby affecting the sampling accuracy.

[0004] It is not difficult to find that the power supply part in the current AFE sampling link is easily affected by total voltage fluctuations and has poor stability. Utility Model Content

[0005] The utility model provides a power supply protection circuit, a sampling circuit and a battery management system, which are used to solve the defects that the power supply part in the current AFE sampling link is easily affected by the total voltage fluctuation and has poor stability.

[0006] On the one hand, the utility model provides a power supply protection circuit, which is arranged on a power supply loop connecting a battery module and an AFE chip, and the circuit comprises: an interference suppression subcircuit, a first filtering subcircuit and a second filtering subcircuit;

[0007] The interference suppression subcircuit is respectively connected to the battery module, the first filtering subcircuit, the second filtering subcircuit and the ground terminal. The first filtering subcircuit is connected to the first power supply pin of the AFE chip, and the second filtering subcircuit is connected to the second power supply pin of the AEF chip.

[0008] According to the power supply protection circuit provided by the utility model, the interference suppression subcircuit includes: at least one common mode inductor;

[0009] The first pin of the common-mode inductor is connected to the positive electrode of the battery module, the second pin of the common-mode inductor is connected to the negative electrode of the battery module, the third pin of the common-mode inductor is respectively connected to the first filter subcircuit and the second filter subcircuit, and the fourth pin of the common-mode inductor is grounded.

[0010] According to the power supply protection circuit provided by the utility model, the first filtering subcircuit includes: a first magnetic bead and a first decoupling module;

[0011] One end of the first magnetic bead is connected to the interference suppression sub-circuit, the other end of the first magnetic bead is connected to the first decoupling module, and the first decoupling module is connected to a first power supply pin of the AFE chip.

[0012] According to the power supply protection circuit provided by the utility model, the first decoupling module includes: a first decoupling capacitor and a second decoupling capacitor;

[0013] The first decoupling capacitor and the second decoupling capacitor are connected in parallel to form a first parallel branch, one end of the first parallel branch is grounded, and the other end of the first parallel branch is respectively connected to the first magnetic bead and the first power supply pin of the AFE chip.

[0014] According to the power supply protection circuit provided by the utility model, the other end of the first parallel branch is connected to the first power supply pin of the AFE chip through the first peripheral sub-circuit;

[0015] The first peripheral sub-circuit includes: a first resistor, a first capacitor, a transistor and a second capacitor;

[0016] The other end of the first parallel branch is connected to the first resistor, the first resistor, the first capacitor and the second capacitor are all connected to the triode, and the triode and the second capacitor are all connected to the first power supply pin of the AFE chip.

[0017] According to the power supply protection circuit provided by the utility model, the second filtering subcircuit includes: a second magnetic bead and a second decoupling module;

[0018] One end of the second magnetic bead is connected to the interference suppression sub-circuit, the other end of the second magnetic bead is connected to the second decoupling module, and the second decoupling module is connected to the second power supply pin of the AEF chip.

[0019] According to the power supply protection circuit provided by the utility model, the second decoupling module includes: a third decoupling capacitor and a fourth decoupling capacitor;

[0020] The third decoupling capacitor and the fourth decoupling capacitor are connected in parallel to form a second parallel branch, one end of the second parallel branch is grounded, and the other end of the second parallel branch is respectively connected to the second magnetic bead and the second power supply pin of the AFE chip.

[0021] According to the power supply protection circuit provided by the utility model, the second filtering subcircuit is connected to the interference suppression subcircuit and the second power supply pin of the AEF chip through the second peripheral subcircuit;

[0022] The second peripheral sub-circuit includes: a diode, a third capacitor, a second resistor and a fourth capacitor;

[0023] The diode and the third capacitor are respectively connected to the interference suppression sub-circuit and the second magnetic bead, one end of the second resistor is connected to the second decoupling module, and the other end of the second resistor and the fourth capacitor are both connected to the second power supply pin of the AEF chip.

[0024] On the other hand, the utility model further provides a sampling circuit for collecting the cell voltage and module temperature of the battery module through an AFE chip, and the circuit includes any one of the power supply protection circuits described above.

[0025] On the other hand, the utility model further provides a battery management system, comprising any one of the above-mentioned power supply protection circuits or the above-mentioned sampling circuits.

[0026] The power supply protection circuit, sampling circuit and battery management system provided by the utility model are provided with an interference suppression subcircuit, a first filtering subcircuit and a second filtering subcircuit, the interference suppression subcircuit is respectively connected to the battery module, the first filtering subcircuit and the second filtering subcircuit, the first filtering subcircuit is connected to the first power supply pin of the AFE chip, and the second filtering subcircuit is connected to the second power supply pin of the AFE chip. The interference suppression subcircuit can filter and suppress the interference signal of the ground line, offset the differential mode interference, and cooperate with the first filtering subcircuit and the second filtering subcircuit to further filter out the clutter and noise interference in the power supply circuit connecting the battery module and the AFE chip, improve the anti-interference ability of the AFE sampling power supply part, and then improve the stability of the AFE sampling power supply part, and solve the problem that the power supply part in the AFE sampling link is easily affected by the total voltage fluctuation and has poor stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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 work.

[0028] Figure 1 This is a schematic diagram of the hardware structure for sampling the cell voltage and module temperature of the battery module;

[0029] Figure 2 This is a schematic diagram of the circuit structure of the traditional AFE chip power supply and sampling part;

[0030] Figure 3 It is a structural schematic diagram of a power supply protection circuit provided by an embodiment of the utility model;

[0031] Figure 4It is a schematic diagram of the statistical results of sampling data of each cell voltage after the relay S2 is closed during the cell voltage sampling process using a traditional AFE power supply circuit;

[0032] Figure 5 It is a schematic diagram of the statistical results of the sampling data of each battery cell voltage after the relay S2 is closed during the battery cell voltage sampling process after the power supply protection circuit is added. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] The present embodiment relates to the field of power supply protection, and can be specifically applied to a scenario in which the cell voltage and module temperature of a battery module are sampled through an AFE chip. Figure 1 The sampling architecture of the cell voltage and module temperature of the battery module is shown as an example. Figure 1 As shown, the sampling architecture includes two battery modules. AFE chip Ua and AFE chip Ub collect the cell voltage and module temperature of battery module PACKA, and AFE chip Uc and AFE chip Ud collect the cell voltage and module temperature of battery module PACKB. The collected data will be transmitted to the main control chip Ue. Battery module PACKA and battery module PACKB can be connected in series through relay S2, and the two battery modules can be connected in parallel through relay S1 and relay S3.

[0035] When relay S2 is closed, battery module PACKA and battery module PACKB are connected in series. The voltage across relay S2 will increase from about -200V to about 300V before and after closing. The voltage fluctuates violently by about 500V, which will cause the power supply circuit of the AFE chip to oscillate, making the AFE chip invalid for a certain period of time.

[0036] In practical applications, the power supply and sampling architecture of the AFE chip can be found in Figure 2 As shown, after the AFE chip U1 draws power from the battery module PACK, one path passes through the magnetic bead Qa for high-frequency filtering, and then passes through the diode D1, the third capacitor C3, and the RC filtering circuit composed of the second resistor R2 and the fourth capacitor C4 to supply power to the second power supply pin VPWER.

[0037] The other path passes through an RC filter circuit composed of a first resistor R1 and a first capacitor C1, and then passes through a transistor Qb and a second capacitor C2 to supply power to the first power supply pin LDO-IN.

[0038] The disadvantages of this power supply circuit are limited filtering capability and insufficient power supply stability. When the high voltage inside the battery module changes drastically during the vehicle power-on process, it is easy to cause oscillation in the two power supply pins VPWER and LDO-IN, resulting in unstable power supply for the AFE chip, resulting in loss of acquisition accuracy or packet loss, and failure to power on the high voltage normally.

[0039] In view of the above technical problems, this embodiment provides relevant solutions. Figures 3 to 5 The detailed scheme of the power supply protection circuit, sampling circuit and battery management system provided by the embodiment of the utility model is described.

[0040] Figure 3 It is a structural schematic diagram of a power supply protection circuit provided in an embodiment of the utility model.

[0041] like Figure 3 As shown, the power supply protection circuit provided by the embodiment of the utility model is specifically arranged on the power supply loop connecting the battery module PACK and the AFE chip U1. The circuit specifically includes: an interference suppression subcircuit 110, a first filtering subcircuit 120 and a second filtering subcircuit 130.

[0042] The interference suppression subcircuit 110 is respectively connected to the battery module PACK, the first filtering subcircuit 120, the second filtering subcircuit 130 and the ground terminal GND1. The first filtering subcircuit 120 is connected to the first power supply pin LD0-IN of the AFE chip U1, and the second filtering subcircuit 130 is connected to the second power supply pin VPWER of the AFE chip U1.

[0043] The solution provided in this embodiment can filter and suppress the interference signal of the ground line through the interference suppression subcircuit 110, offset the differential mode interference, and cooperate with the first filtering subcircuit 120 and the second filtering subcircuit 130 to further filter out the clutter and noise interference in the power supply circuit connecting the battery module PACK and the AFE chip U1, thereby improving the anti-interference ability of the AFE sampling power supply part, and thus improving the stability of the AFE sampling power supply part.

[0044] In one embodiment, see Figure 3 The interference suppression sub-circuit 110 specifically includes: at least one common-mode inductor L1.

[0045] The first pin of the common-mode inductor L1 is connected to the positive electrode of the battery module PACK, the second pin of the common-mode inductor L1 is connected to the negative electrode of the battery module PACK, the third pin of the common-mode inductor L1 is respectively connected to the first filtering subcircuit 120 and the second filtering subcircuit 130, and the fourth pin of the common-mode inductor L1 is grounded.

[0046] In practical applications, one or more common-mode inductors may be provided. When multiple common-mode inductors are provided, the multiple common-mode inductors may be connected in series to achieve a better interference suppression function.

[0047] In one embodiment, see Figure 3 The first filtering sub-circuit 120 specifically includes: a first magnetic bead Q1 and a first decoupling module.

[0048] One end of the first magnetic bead Q1 is connected to the interference suppression sub-circuit 110 , and the other end of the first magnetic bead Q1 is connected to the first decoupling module, and the first decoupling module is connected to the first power supply pin LDO-IN of the AFE chip U1 .

[0049] In one embodiment, see Figure 3 The first decoupling module specifically includes: a first decoupling capacitor C5 and a second decoupling capacitor C6.

[0050] The first decoupling capacitor C5 and the second decoupling capacitor C6 are connected in parallel to form a first parallel branch, one end of the first parallel branch is grounded GND1, and the other end of the first parallel branch is respectively connected to the first magnetic bead Q1 and the first power supply pin LDO-IN of the AFE chip U1.

[0051] In one embodiment, see Figure 3 The other end of the first parallel branch is specifically connected to the first power supply pin LDO-IN of the AFE chip U1 through the first peripheral sub-circuit.

[0052] The first peripheral sub-circuit includes: a first resistor R1, a first capacitor C1, a transistor Qb and a second capacitor C2.

[0053] The other end of the first parallel branch is connected to the first resistor R1, the first resistor R1, the first capacitor C1 and the second capacitor C2 are all connected to the transistor Qb, and the transistor Qb and the second capacitor C2 are all connected to the first power supply pin LDO-IN of the AFE chip U1.

[0054] In this embodiment, for the power supply part of the LDO-IN pin, after the AFE chip U1 takes power from the battery module PACK, it passes through the common-mode inductor L1, the first magnetic bead Q1, the first decoupling capacitor C5, the second decoupling capacitor C6, the RC filter circuit composed of the first resistor R1 and the first capacitor C1, the transistor Qb and the second capacitor C2 in sequence, and then supplies power to the first power supply pin LDO-IN.

[0055] Among them, the common-mode inductor L1 can effectively filter and suppress the interference signal of the ground line, offset the differential mode interference, and reduce the impact of interference on the power supply. Combined with the first magnetic bead Q1, the first decoupling capacitor C5 and the second decoupling capacitor C6, it can further filter out clutter and noise and enhance the filtering capability of the entire power supply circuit.

[0056] In one embodiment, see Figure 3 The second filtering sub-circuit 130 specifically includes: a second magnetic bead Q2 and a second decoupling module.

[0057] One end of the second magnetic bead Q2 is connected to the interference suppression sub-circuit 110 , and the other end of the second magnetic bead Q2 is connected to the second decoupling module, and the second decoupling module is connected to the second power supply pin VPWER of the AEF chip U1 .

[0058] In one embodiment, see Figure 3 The second decoupling module specifically includes: a third decoupling capacitor C7 and a fourth decoupling capacitor C8.

[0059] The third decoupling capacitor C7 and the fourth decoupling capacitor C8 are connected in parallel to form a second parallel branch, one end of the second parallel branch is grounded, and the other end of the second parallel branch is respectively connected to the second magnetic bead Q2 and the second power supply pin VPWER of the AFE chip U1.

[0060] In one embodiment, see Figure 3 The second filtering sub-circuit 130 is specifically connected to the interference suppression sub-circuit 110 and the second power supply pin VPWER of the AEF chip U1 through the second peripheral sub-circuit.

[0061] The second peripheral sub-circuit specifically includes: a diode D1, a third capacitor C3, a second resistor R2 and a fourth capacitor C4.

[0062] One end of the diode D1 and one end of the third capacitor C3 are respectively connected to the interference suppression sub-circuit 110 and the second magnetic bead Q2, the other end of the diode D1 and the other end of the third capacitor C3 are grounded, one end of the second resistor R2 is connected to the second decoupling module, and the other end of the second resistor R2 and the fourth capacitor C4 are connected to the second power supply pin VPWER of the AEF chip U1.

[0063] In this embodiment, for the power supply part of the VPWER pin, after the AFE chip takes power from the battery module PACK, it passes through the common-mode inductor L1, the diode D1, the third capacitor C3, the second magnetic bead Q2, the third decoupling capacitor C7, the fourth decoupling capacitor C8 and the RC filter circuit composed of the second resistor R2 and the fourth capacitor C4 to supply power to the second power supply pin VPWER.

[0064] Among them, the common-mode inductor L1 can form an LC filtering circuit with the third capacitor C3, which can not only block the interference caused by high-frequency signals, but also block the interference caused by low-frequency signals. The filtering capability is effectively improved. In conjunction with the second magnetic bead Q2, the third decoupling capacitor C7 and the fourth decoupling capacitor C8, clutter and noise can be further filtered out.

[0065] It should be noted that Figure 2 and Figure 3 The CTn-1 pin, CTn and CTn+1 in the AFE chip shown are all sampling pins, which can cooperate with the relevant devices on the corresponding branches to realize the sampling of the battery cell voltage. Since the battery cell voltage sampling process is a public scheme and does not fall within the protection scope of the present utility model, it is not described in detail here.

[0066] In summary, the optimized power supply protection circuit can effectively solve the problem of invalid cell voltage sampling when the power supply voltage fluctuates. The effectiveness of the improvement scheme provided in this embodiment is verified in combination with specific test data in actual applications.

[0067] Figure 4 Is adopted Figure 2 The AFE power supply circuit shown in the figure realizes the sampling process of the battery cell voltage, and after the relay S2 is closed, the sampling data statistics diagram of each battery cell voltage; Figure 5 Is adopted Figure 3 The figure shows a statistical diagram of sampling data of each cell voltage after the relay S2 is closed during the cell voltage sampling process after the power supply protection circuit is added.

[0068] Will Figure 4 The data shown are Figure 5 After comparing the data shown, it can be found that Figure 4 After the relay S2 is closed, there is a sampling invalid section M of more than 300ms in the voltage sampling link. Figure 5 After the relay S2 is repeatedly closed and opened, the voltage sampling link is effective. Based on this, it can be proved that the power supply protection circuit provided in this embodiment can effectively improve the power supply stability and anti-interference ability of the AFE chip.

[0069] In addition, an embodiment of the utility model further provides a sampling circuit, which is specifically an AFE sampling circuit, mainly used to collect the cell voltage and module temperature of the battery module through the AFE chip. The circuit includes the power supply protection circuit provided in the above embodiments.

[0070] In addition, an embodiment of the utility model further provides a battery management system, including the power supply protection circuit provided by the above embodiments or the above sampling circuit.

[0071] It should be noted that the power supply protection circuit, sampling circuit and battery management system provided in the embodiments of the utility model can be applied to energy storage devices, and the energy storage devices can be vehicles, operating machinery, etc.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A power supply protection circuit, characterized in that: The circuit is provided on a power supply circuit connecting the battery module and the AFE chip, and includes: an interference suppression subcircuit, a first filtering subcircuit and a second filtering subcircuit; The interference suppression subcircuit is connected to the battery module, the first filtering subcircuit, the second filtering subcircuit and the ground terminal respectively, the first filtering subcircuit is connected to the first power supply pin of the AFE chip, and the second filtering subcircuit is connected to the second power supply pin of the AFE chip; The first filtering subcircuit comprises: a first magnetic bead and a first decoupling module; One end of the first magnetic bead is connected to the interference suppression sub-circuit, the other end of the first magnetic bead is connected to the first decoupling module, and the first decoupling module is connected to a first power supply pin of the AFE chip.

2. The power supply protection circuit according to claim 1, characterized in that: The interference suppression subcircuit includes: at least one common mode inductor; The first pin of the common-mode inductor is connected to the positive electrode of the battery module, the second pin of the common-mode inductor is connected to the negative electrode of the battery module, the third pin of the common-mode inductor is respectively connected to the first filter subcircuit and the second filter subcircuit, and the fourth pin of the common-mode inductor is grounded.

3. The power supply protection circuit according to claim 1, characterized in that: The first decoupling module includes: a first decoupling capacitor and a second decoupling capacitor; The first decoupling capacitor and the second decoupling capacitor are connected in parallel to form a first parallel branch, one end of the first parallel branch is grounded, and the other end of the first parallel branch is respectively connected to the first magnetic bead and the first power supply pin of the AFE chip.

4. The power supply protection circuit according to claim 3, characterized in that: The other end of the first parallel branch is connected to the first power supply pin of the AFE chip through a first peripheral sub-circuit; The first peripheral sub-circuit includes: a first resistor, a first capacitor, a transistor and a second capacitor; The other end of the first parallel branch is connected to the first resistor, the first resistor, the first capacitor and the second capacitor are all connected to the triode, and the triode and the second capacitor are all connected to the first power supply pin of the AFE chip.

5. The power supply protection circuit according to claim 1, characterized in that: The second filtering subcircuit comprises: a second magnetic bead and a second decoupling module; One end of the second magnetic bead is connected to the interference suppression sub-circuit, the other end of the second magnetic bead is connected to the second decoupling module, and the second decoupling module is connected to the second power supply pin of the AFE chip.

6. The power supply protection circuit according to claim 5, characterized in that: The second decoupling module includes: a third decoupling capacitor and a fourth decoupling capacitor; The third decoupling capacitor and the fourth decoupling capacitor are connected in parallel to form a second parallel branch, one end of the second parallel branch is grounded, and the other end of the second parallel branch is respectively connected to the second magnetic bead and the second power supply pin of the AFE chip.

7. The power supply protection circuit according to claim 5, characterized in that: The second filtering subcircuit is connected to the interference suppression subcircuit and the second power supply pin of the AFE chip through a second peripheral subcircuit; The second peripheral sub-circuit includes: a diode, a third capacitor, a second resistor and a fourth capacitor; The diode and the third capacitor are respectively connected to the interference suppression sub-circuit and the second magnetic bead, one end of the second resistor is connected to the second decoupling module, and the other end of the second resistor and the fourth capacitor are both connected to the second power supply pin of the AFE chip.

8. A sampling circuit, characterized in that: Used to collect the cell voltage and module temperature of the battery module through the AFE chip, the circuit includes the power supply protection circuit as described in any one of claims 1 to 7.

9. A battery management system, characterized in that: It comprises the power supply protection circuit as claimed in any one of claims 1 to 7 or the sampling circuit as claimed in claim 8.

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