ADBMS2950-based high-voltage relay adhesion detection circuit

Abstract

The utility model discloses a high-voltage relay adhesion detection circuit based on ADBMS2950, the circuit comprises a high-voltage diagnosis module and a voltage conversion circuit, before sampling, VREF1P25 is self-checked through an AuxADC in the high-voltage diagnosis module, before high voltage sampling, ADC in ADBMS2950 is self-checked through sampling VREF1P25 voltage, V1ADC and V2ADC are switched through MUX in the high-voltage diagnosis module to alternately sample high-voltage detection point voltage, and the ADBMS2950 high-voltage relay adhesion detection circuit based on ADBMS2950 is realized. VREF1P25 is self-detected through an AuxADC in the ADBMS2950 before sampling, sampling errors caused by pull-up are reduced, ADC such as a V1ADC, a V2ADC, a VBAT1 and a VBAT2 in the ADBMS2950 are self-detected through sampling the voltage of the VREF1P25 before high voltage sampling, voltages of detection points B, C, D, E and F of high voltage are alternately sampled through switching the V1ADC and the V2ADC by an MUX in the ADBMS2950, and the reliability of the system is improved through redundancy design.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric vehicle battery management, and particularly relates to a high-voltage relay adhesion detection circuit based on ADBMS2950. Background Art

[0002] Currently, high-voltage relay adhesion detection circuits are primarily implemented using current detection, voltage detection, and time detection. The voltage detection approach, which uses an MCU, ADC module, and voltage divider circuit, is particularly common. This approach is independent of the high-voltage, insulation, and current detection modules. Each ADC module has a different reference power supply, resulting in varying sampling accuracy and impacting system calibration and execution strategies. Achieving ASIL D functional safety with independent modules requires additional redundant design, resulting in significant design complexity and high material costs. Utility Model Content

[0003] To achieve the above-mentioned purpose, the technical solution of the utility model is as follows: a high-voltage relay adhesion detection circuit based on ADBMS2950, the circuit including a high-voltage diagnostic module and a voltage conversion circuit, self-checking VREF1P25 through the internal Aux_ADC of the high-voltage diagnostic module before sampling, self-checking the internal ADC of ADBMS2950 by sampling the VREF1P25 voltage before sampling the high voltage, and alternately sampling the high-voltage detection point voltage through switching V1ADC and V2ADC inside the high-voltage diagnostic module.

[0004] As an improvement of the present invention, the battery pack detection P is directly connected to the module system ground GND_A as a voltage reference point, and the battery pack high-voltage detection points A, B, C, D, E, and F are respectively connected to the high-voltage sampling input signals HV_VA, HV_VB, HV_VC, HV_VD, HV_VE, and HV_VF.

[0005] As an improvement of the present invention, the voltage conversion circuit includes resistors R1 to R6, R9 to R14, R17 to R22, R25 to R27, R29 to R31, R33 to R38, and R40 to R45.

[0006] As an improvement of the present invention, the circuit detects the total positive voltage HV_VA of the battery pack through VBAT1 and VBAT2; and enables MOSFET Q1, MOSFET Q2, and MOSFET Q3 through the high level of output pins EN_B&C&D.

[0007] As an improvement of the present invention, the circuit enables MOSFET Q4 and MOSFET Q5 through the high level of pins EN_E&F, and enables MOSFET Q6 and MOSFET Q7 through the high level of pin EN_A; the V1~V6 ports collect the voltage of the voltage divider circuit through the internal ADC.

[0008] As an improvement of the present invention, the battery pack high-voltage signal HV_VA signal is divided by R33~R38 and R40~R45 respectively to become ADC signals HV_VA_MON1 and HV_VA_MON2; the HV_VB signal is divided by R1~R6 to become the ADC signal HV_VB_MON; the HV_VC signal is divided by R9~R14 and VREF1P25 to become the ADC signal HV_VC_MON; the HV_VD signal is divided by R17~R22 and VREF1P25 to become the ADC signal HV_VD_MON; the HV_VE signal is divided by R25~R27 and VREF1P25 to become the ADC signal HV_VE_MON; the HV_VF signal R29~R31 and VREF1P25 to become the ADC signal HV_VF_MON; and is used for sampling of ADBMS2950.

[0009] Compared with the prior art, the beneficial effects of the present invention are:

[0010] ① Before sampling, self-check VREF1P25 through Aux_ADC (sampling accuracy 0.1%) inside ADBMS2950 to reduce the sampling error introduced by pull-up;

[0011] ② Before sampling high voltage, perform self-test on ADCs such as V1ADC, V2ADC, VBAT1, and VBAT2 inside ADBMS2950 by sampling the VREF1P25 voltage;

[0012] ③ The internal MUX of ADBMS2950 switches V1ADC and V2ADC to alternately sample the voltages of high-voltage detection points B, C, D, E, and F. The redundant design increases system reliability.

[0013] ④ Confirm the relay status by calculating the voltage difference between the detection points on both sides of the relay, select the appropriate voltage divider network, and improve the system's anti-interference ability;

[0014] ⑤ Integrate relay adhesion detection, high voltage detection, insulation detection, and current detection into one module, with high failure sampling accuracy, meeting functional safety ASIL D. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the electric vehicle relay status diagnostic circuit in this embodiment;

[0016] Figure 2Schematic diagram of high-voltage sampling point. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0018] Example: Figure 1 As shown, this embodiment is a high-voltage relay adhesion detection circuit based on ADBMS2950, which includes a high-voltage diagnostic module and a voltage conversion circuit. Before sampling, VREF1P25 is self-checked through the internal Aux_ADC of the high-voltage diagnostic module. Before sampling the high voltage, the internal ADC of ADBMS2950 is self-checked by sampling the VREF1P25 voltage. The high-voltage detection point voltage is alternately sampled by switching V1ADC and V2ADC through the internal MUX of the high-voltage diagnostic module.

[0019] The circuit includes a high voltage diagnostic module (ADBMS2950).

[0020] like Figure 2 As shown, the battery pack detection P is directly connected to the module system ground GND_A as the voltage reference point, and the battery pack high-voltage detection points A, B, C, D, E, and F are respectively connected to the high-voltage sampling input signals HV_VA, HV_VB, HV_VC, HV_VD, HV_VE, and HV_VF. The total positive voltage (HV_VA) of the battery pack can be detected through VBAT1 and VBAT2. The VREF1P25 port bypass capacitor 1.1uf outputs 1.25V to provide a pull-up level for the sampling circuit; the MOSFETs Q1, MOSFETQ2, and MOSFETQ3 are enabled by a high level on the output pins EN_B&C&D, the MOSFETs Q4 and MOSFETQ5 are enabled by a high level on the pins EN_E&F, and the MOSFETs Q6 and MOSFETQ7 are enabled by a high level on the pin EN_A; the V1~V6 ports collect the voltage of the voltage divider circuit through the internal ADC.

[0021] The circuit includes a voltage conversion circuit consisting of resistors R1, R2, R3, R4, R5, R6, R9, R10, R11, R12, R13, R14, R17, R18, R19, R20, R21, R22, R25, R26, R27, R29, R30, R31, R33, R34, R35, R36, R37, R38, R40, R41, R42, R43, R44, and R45. The battery pack high-voltage signal HV_VA is divided down by R33~R38 and R40~R45 to become ADC signals HV_VA_MON1 and HV_VA_MON2 respectively; the HV_VB signal is divided down by R1~R6 to become ADC signal HV_VB_MON; the HV_VC signal is divided down by R9~R14 and VREF1P25 to become ADC signal HV_VC_MON; the HV_VD signal is divided down by R17~R22 and VREF1P25 to become ADC signal HV_VD_MON; the HV_VE signal is divided down by R25~R27 and VREF1P25 to become ADC signal HV_VE_MON; the HV_VF signal is divided down by R29~R31 and VREF1P25 to become ADC signal HV_VF_MON; and is used for sampling of ADBMS2950.

[0022] This embodiment of the "electric vehicle relay adhesion diagnosis circuit" is combined with Figure 1 and Figure 2 For further explanation: Take the battery pack voltage FS=400VDC as an example:

[0023] ① The ADBMS2950 uses its internal Aux_ADC (sampling accuracy 0.1%) to self-test the output voltage of power supply VREF1P25, recorded as VREF. ② The ADBMS2950's internal V1ADC (sampling accuracy 0.1%) samples the voltages of HV_VC_MON, HV_VD_MON, HV_VE_MON, and HV_VF_MON. The maximum voltage difference between these four samples and VREF is recorded as △V1. When △V1 ≤ 0.05V, the pull-up power supply is considered normal. ③ Enable EN_A, sample HV_VA_MON1 voltage VA1 using R33-R37 and R38, and sample HV_VA_MON2 using R40-R44 and R45. The system then samples voltage VA2. Using different voltage divider resistors R38 and R45 to change the voltage divider structure, heterogeneous redundancy design improves reliability. ④ Enable EN_E&F, sample HV_VE_MON, record it as VE, close the main negative relay, sample the HV_VF_MON voltage, record it as VF, and refer to Table 1 to diagnose the status of the main negative and fast charge negative relays. ⑤ Enable EN_B&C&D, sample the HV_VB_MON, HV_VC_MON, and HV_VD_MON voltages, record them as VB, VC, and VD, and refer to Table 1 to diagnose the status of the main positive and fast charge positive relays. Figure 1 The resistors for R1-R5, R9-R13, R17-R21, R33-R37, and R40-R44 are 330kΩ, 0.1%, 1206Ω; the resistors for R6, R14, R22, and R38 are 3.3kΩ, 0.1%, 1206Ω; the resistors for R25, R26, R29, R27, R30, R31, and R45 are 5kΩ, 0.1%, 1206Ω; and the resistors for R8, R16, R24, R28, R32, R39, and R46 are 33Ω, 10%, 0603Ω. The following table shows the relay status comparison for a 400VDC battery pack system.

[0024]

[0025] It should be noted that the above content only illustrates the technical idea of the utility model and cannot be used to limit the protection scope of the utility model. For ordinary technicians in this technical field, they can make several improvements and modifications without departing from the principles of the utility model. These improvements and modifications all fall within the protection scope of the claims of the utility model.

Claims

1. A high-voltage relay adhesion detection circuit based on ADBMS2950, characterized in that: The circuit includes a high-voltage diagnostic module and a voltage conversion circuit. Before sampling, VREF1P25 is self-checked through the Aux_ADC inside the high-voltage diagnostic module. Before sampling high voltage, the ADC inside the ADBMS2950 is self-checked by sampling the VREF1P25 voltage. The high-voltage detection point voltage is alternately sampled by switching V1ADC and V2ADC through the MUX inside the high-voltage diagnostic module.

2. A high-voltage relay adhesion detection circuit based on ADBMS2950 according to claim 1, characterized in that, The battery pack detection P is directly connected to the module system ground GND_A as the voltage reference point, and the battery pack high-voltage detection points A, B, C, D, E, and F are connected to the high-voltage sampling input signals HV_VA, HV_VB, HV_VC, HV_VD, HV_VE, and HV_VF respectively.

3. A high-voltage relay adhesion detection circuit based on ADBMS2950 according to claim 1, characterized in that, The voltage conversion circuit includes resistors R1 to R6, R9 to R14, R17 to R22, R25 to R27, R29 to R31, R33 to R38, and R40 to R45.

4. A high-voltage relay adhesion detection circuit based on ADBMS2950 according to claim 1, characterized in that, The circuit detects the total positive voltage HV_VA of the battery pack through VBAT1 and VBAT2; and enables MOSFET Q1, MOSFET Q2, and MOSFET Q3 through a high level of output pins EN_B&C&D.

5. A high-voltage relay adhesion detection circuit based on ADBMS2950 according to claim 1, characterized in that, The circuit enables MOSFET Q4 and MOSFET Q5 through a high level of pins EN_E&F, and enables MOSFET Q6 and MOSFET Q7 through a high level of pin EN_A; ports V1 to V6 collect the voltage of the voltage divider circuit through an internal ADC.

6. A high-voltage relay adhesion detection circuit based on ADBMS2950 according to claim 1, characterized in that, The battery pack high-voltage signal HV_VA is divided down by R33~R38 and R40~R45 to become ADC signals HV_VA_MON1 and HV_VA_MON2 respectively; the HV_VB signal is divided down by R1~R6 to become ADC signal HV_VB_MON; the HV_VC signal is divided down by R9~R14 and VREF1P25 to become ADC signal HV_VC_MON; the HV_VD signal is divided down by R17~R22 and VREF1P25 to become ADC signal HV_VD_MON; the HV_VE signal is divided down by R25~R27 and VREF1P25 to become ADC signal HV_VE_MON; the HV_VF signal is divided down by R29~R31 and VREF1P25 to become ADC signal HV_VF_MON.

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