WO2020177639A1 - 绝缘检测电路及检测方法、电池管理*** - Google Patents

绝缘检测电路及检测方法、电池管理*** Download PDF

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Publication number
WO2020177639A1
WO2020177639A1 PCT/CN2020/077269 CN2020077269W WO2020177639A1 WO 2020177639 A1 WO2020177639 A1 WO 2020177639A1 CN 2020077269 W CN2020077269 W CN 2020077269W WO 2020177639 A1 WO2020177639 A1 WO 2020177639A1
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Prior art keywords
voltage
module
resistance value
insulation
sampling
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PCT/CN2020/077269
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English (en)
French (fr)
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李盟
但志敏
张伟
侯贻真
孙卫平
李前邓
刘昌鑑
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宁德时代新能源科技股份有限公司
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Publication of WO2020177639A1 publication Critical patent/WO2020177639A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/16—Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
    • G01R27/18—Measuring resistance to earth, i.e. line to ground
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/3644—Constructional arrangements

Definitions

  • This application relates to the field of battery technology, and in particular to an insulation detection circuit and detection method, and a battery management system.
  • the battery pack is responsible for providing electric energy for the electric motor of the electric vehicle, and the battery pack is connected to the load through the positive switch module and the negative switch module respectively.
  • the battery pack is one of the key components of electric vehicles, and the safety of its high-voltage power is the primary consideration of the power battery system. Therefore, the inspection of the insulation performance of electric vehicles is an essential part of the design, that is to say, in advance Detecting and issuing early warning of insulation abnormalities has become particularly important.
  • the purpose of this application is to provide an insulation detection circuit, a detection method, and a battery management system.
  • the insulation detection circuit can separately detect the insulation resistance of the positive high-voltage circuit on the side of the battery pack to be tested relative to the reference voltage terminal and the battery to be tested.
  • the insulation resistance of the negative high-voltage circuit on the side of the group relative to the reference reference voltage terminal so as to achieve independent alarms of high-voltage positive to ground voltage and high-voltage negative to low-voltage ground, avoiding the risk of false alarms.
  • an embodiment of the present application provides an insulation detection circuit, which includes: a first switch module, a first voltage dividing module, a second voltage dividing module, an isolation module, a third voltage dividing module, and a signal generator And the processor;
  • the first switch module, the first voltage dividing module and the second voltage dividing module are arranged in series between the positive electrode of the battery pack under test and the reference voltage terminal;
  • the isolation module, the third voltage dividing module and the signal generator are arranged in series between the positive electrode of the battery pack under test and the reference voltage terminal;
  • a first sampling point is arranged between the first voltage dividing module and the second voltage dividing module, a second sampling point is arranged between the isolation module and the third voltage dividing module, and a second sampling point is arranged between the third voltage dividing module and the signal generator.
  • the first sampling point is configured to provide a first sampling signal
  • the second sampling point is configured to provide a second sampling signal
  • the third sampling point is configured to provide a third sampling signal
  • the processor is configured to calculate the insulation resistance of the positive high voltage circuit on the side of the battery pack under test relative to the reference reference voltage terminal and the negative high voltage circuit on the side of the battery pack under test based on the first sampling signal, the second sampling signal and the third sampling signal Relative to the insulation resistance of the reference voltage terminal.
  • the first switching module includes a first switching device, the first voltage dividing module includes a first resistor network, the second voltage dividing module includes a second resistor network, and the first sampling point is located at Between the first resistance network and the second resistance network.
  • the isolation module includes a first capacitor
  • the third voltage divider module includes a third resistor network
  • the second sampling point is located between the first capacitor and the third resistor network
  • the third sampling The point is located between the third resistor network and the signal generator.
  • the insulation detection circuit further includes a first voltage follower and a second voltage follower; wherein, the first input terminal of the first voltage follower is connected to the second sampling point, and the first The second input terminal of a voltage follower is connected to the output terminal of the first voltage follower, and the output terminal of the first voltage follower is also connected to the processor; the first input terminal of the second voltage follower is connected to the third sampling point The second input terminal of the second voltage follower is connected with the output terminal of the second voltage follower, and the output terminal of the second voltage follower is also connected with the processor.
  • the insulation detection circuit further includes: a first filter module, a second filter module, and a third filter module; wherein the first end of the first filter module is connected to the first sampling point , The second end of the first filter module is connected to the processor; the first end of the second filter module is connected to the second sampling point, and the second end of the second filter module is connected to the first input end of the first voltage follower; The first end of the third filter module is connected to the third sampling point, and the second end of the third filter module is connected to the first input end of the second voltage follower.
  • the insulation detection circuit further includes a first voltage follower and a second voltage follower; wherein, the first input terminal of the first voltage follower is connected to the second sampling point, and the first The second input terminal of a voltage follower is connected to the output terminal of the first voltage follower, and the output terminal of the first voltage follower is also connected to the processor; the first input terminal of the second voltage follower is connected to the third sampling point The second input terminal of the second voltage follower is connected with the output terminal of the second voltage follower, and the output terminal of the second voltage follower is also connected with the processor.
  • an embodiment of the present application provides a battery management system, which includes the insulation detection circuit described above.
  • an embodiment of the present application provides a detection method of an insulation detection circuit, which is used in the above-mentioned insulation detection circuit, and the detection method includes:
  • the first sampling signal, the second sampling signal and the third sampling signal calculate the insulation resistance of the positive high-voltage circuit on the side of the battery pack under test relative to the reference reference voltage terminal and the negative high-voltage circuit on the side of the battery pack under test relative to the reference reference voltage The insulation resistance of the terminal.
  • the insulation resistance of the positive high-voltage circuit on the side of the battery pack to be tested relative to the reference voltage terminal and the standby Measuring the insulation resistance of the negative high-voltage circuit on the side of the battery pack relative to the reference reference voltage terminal includes: obtaining the first parallel resistance value according to the second sampling signal and the third sampling signal, where the first parallel resistance value is the side of the battery pack under test The parallel resistance of the insulation resistance of the positive high-voltage circuit relative to the reference reference voltage terminal and the insulation resistance of the negative high-voltage circuit on the side of the battery pack to be tested relative to the reference reference voltage terminal; according to the first sampling signal and the first parallel resistance, the waiting Measure the insulation resistance of the positive high-voltage circuit on the side of the battery pack relative to the reference reference voltage terminal and the insulation resistance of the negative high-voltage circuit on the side of the battery pack to be tested relative to the reference reference voltage end.
  • the positive switch module is controlled to be turned off, the negative switch module is turned off, and the first switch module is turned off, the second sampling signal is obtained from the second sampling point, and the second sampling signal is obtained from the third sampling point.
  • Obtaining the third sampling signal includes: controlling the positive switch module to close, the negative switch module to close, the first switch module to open, obtain the fourth sampling signal from the second sampling point, and obtain the fifth sampling signal from the third sampling point; The fourth sampling signal and the fifth sampling signal are used to obtain the second parallel resistance value.
  • the second parallel resistance value is the insulation resistance value of the positive high voltage circuit on the side of the battery pack to be tested relative to the reference reference voltage terminal, and the negative pole high voltage of the battery pack to be tested.
  • the second sampling signal is obtained from the second sampling point, and the third sampling signal is obtained from the third sampling point.
  • the detection method further includes: according to the second sampling signal and The third sampling signal is used to obtain the first parallel resistance value.
  • the first parallel resistance value is the insulation resistance value of the positive high-voltage circuit on the side of the battery pack under test relative to the reference reference voltage terminal and the negative high-voltage circuit on the side of the battery pack under test relative to the reference reference.
  • the parallel resistance value of the insulation resistance value of the voltage terminal according to the first parallel resistance value and the second parallel resistance value, the third parallel resistance value is obtained, and the third parallel resistance value is the parallel resistance value of the insulation resistance value of the three-phase end of the vehicle; If the third parallel resistance is less than the second alarm threshold, it is determined that the insulation resistance of the three-phase end of the load is faulty; if the third parallel resistance is greater than the second alarm threshold, it is determined that the insulation resistance of the battery pack to be tested is faulty .
  • the isolation module, the third voltage divider module and the signal generator are arranged in series, but also the first switch module is arranged in series.
  • the first voltage divider module and the second voltage divider module are arranged in series, but also the first switch module is arranged in series.
  • the first voltage divider module and the second voltage divider module are arranged in series.
  • a first sampling point is set between the first voltage dividing module and the second voltage dividing module
  • a second sampling point is set between the isolation module and the third voltage dividing module
  • the third voltage dividing module is between the signal generator
  • the processor can detect the battery pack under test based on the first sampling signal provided by the first sampling point, the second sampling signal provided by the second sampling point, and the third sampling signal provided by the third sampling point.
  • the insulation detection circuit in the embodiment of the present application is additionally provided with a first switch module, a first voltage divider module, and a second voltage divider module, the battery to be tested can be detected
  • the battery pack to be tested is further tested separately
  • FIG. 1 is a schematic structural diagram of an insulation detection circuit provided by an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of an insulation detection circuit provided by another embodiment of the application.
  • FIG. 3 is a schematic flowchart of a detection method of an insulation detection circuit provided by an embodiment of the application.
  • 5 is an equivalent circuit diagram of the insulation detection circuit when the positive switch module is disconnected, the negative switch module is disconnected, and the first switch module is disconnected according to an embodiment of the application;
  • FIG. 6 is a schematic flowchart of a detection method of an insulation detection circuit provided by another embodiment of the application.
  • FIG. 7 is an equivalent circuit diagram of the insulation detection circuit corresponding to FIG. 5;
  • FIG. 8 is a schematic flowchart of a detection method of an insulation detection circuit provided by another embodiment of this application.
  • 9 is an equivalent circuit diagram of the insulation detection circuit when the positive switch module is closed, the negative switch module is closed, and the first switch module is disconnected according to an embodiment of the application;
  • FIG. 10 is a schematic flowchart of a detection method of an insulation detection circuit provided by still another embodiment of the application.
  • the insulation test of the battery pack is mainly based on the AC injection method or the partial pressure method.
  • the AC injection method or the partial pressure method can only detect the parallel connection of the insulation resistance of the vehicle's high voltage positive to the low voltage ground and the high voltage negative to the low voltage ground.
  • the insulation resistance value of the vehicle's high-voltage positive to low-voltage ground is low, and the high-voltage negative to low-voltage ground insulation resistance is also low, the insulation resistance of the high-voltage positive to low-voltage ground and the high-voltage negative to low-voltage ground may be greater than the alarm threshold, but both
  • the parallel value is less than the alarm threshold, so there is a risk of false alarms.
  • the embodiments of the present application provide an insulation detection circuit, a detection method, and a battery management system.
  • the insulation resistance of the positive high-voltage circuit on the side of the battery pack to be tested relative to the reference reference voltage terminal can be separately detected.
  • Value i.e. the insulation resistance value of the high-voltage positive to the low-voltage ground
  • the insulation resistance value of the negative high-voltage circuit on the side of the battery under test relative to the reference voltage terminal i.e. the insulation resistance of the high-voltage negative to the low-voltage ground
  • the battery pack to be tested in the embodiment of the application may be a lithium ion battery, a lithium metal battery, a lead-acid battery, a nickel barrier battery, a nickel hydrogen battery, a lithium sulfur battery, a lithium air battery or a sodium ion battery, which is not limited here.
  • the battery pack to be tested can also be a single battery cell, a battery module or a battery pack, which is not limited here.
  • FIG. 1 is a schematic structural diagram of an insulation detection circuit provided by an embodiment of the application.
  • the insulation detection circuit includes: a first switch module K1, a first voltage divider module F1, a second voltage divider module F2, an isolation module C1, a third voltage divider module F3, a signal generator Y1, and a processor P1.
  • the first switch module K1, the first voltage dividing module F1, and the second voltage dividing module F2 are arranged in series between the positive electrode of the battery under test and the reference voltage terminal GND.
  • the sequence of the first switch module K1, the first voltage dividing module F1, and the second voltage dividing module F2 is adjustable, and a first sampling point S1 is provided between the first voltage dividing module F1 and the second voltage dividing module F2.
  • the sampling point S1 is configured to provide a first sampling signal.
  • the isolation module C1, the third voltage dividing module F3 and the signal generator Y1 are arranged in series between the positive electrode of the battery pack under test and the reference voltage terminal GND.
  • a second sampling point S2 is provided between the isolation module C1 and the third voltage dividing module F3, and the second sampling point S2 is configured to provide a second sampling signal; and the third voltage dividing module F3 and the signal generator Y1 are provided between There is a third sampling point S3, and the third sampling point S3 is configured to provide a third sampling signal.
  • the processor P1 is configured to calculate the insulation resistance RP of the positive high-voltage circuit on the side of the battery pack under test relative to the reference reference voltage terminal GND according to the first sampling signal, the second sampling signal, and the third sampling signal, and the battery pack under test The insulation resistance RN of the negative high-voltage circuit on the side relative to the reference voltage terminal GND.
  • the processor P1 may be a processor P1 dedicated to the insulation detection circuit, or may be a processor P1 shared with other circuits.
  • Figure 1 also shows CP, CN, Q1 ⁇ Q6, Ru, Rv and Rw, where CP and CN are the equivalent capacitances between the positive and negative electrodes of the battery under test and its case, and Q1 ⁇ Q6 are The full-bridge power unit is used to convert the DC voltage of the battery pack under test into the three-phase voltage required by the load (such as a motor). Ru, Rv and Rw are the equivalents between the three-phase branch and the body of the vehicle. Insulation resistance, Cx is X capacitance.
  • Figure 1 also shows the positive switch module K+ and the negative switch module K-.
  • the positive switch module K+ and the negative switch module K- can be understood as switching devices located between the battery pack to be tested and the load circuit, such as a relay. , Insulated Gate Bipolar Transistor (IGBT), etc.
  • IGBT Insulated Gate Bipolar Transistor
  • the on-off state of the positive switch module K+ and the negative switch module K- can be controlled by the processor P1 or other control devices, which is not limited here.
  • Figure 1 also shows the reference reference voltage terminal GND.
  • the actual voltage of the reference reference voltage terminal GND can be set according to the working scenario and requirements of the insulation detection circuit.
  • the reference reference voltage terminal GND can be the battery pack case.
  • the signal generator Y1 may be a direct digital frequency synthesizer (Direct Digital Synthesizer, DDS), which is used to generate an AC source signal with a stable and adjustable frequency and a small output voltage amplitude.
  • DDS Direct Digital Synthesizer
  • the AC source signal is injected and detected. After the loop, collect the amplitude signal of the signal source voltage (ie the sampling signal at the second sampling point S2), and the amplitude signal between the isolation module C1 and the third voltage divider module F3 (ie the sampling at the third sampling point S3) signal).
  • the isolation module C1 between the positive pole of the battery under test of the insulation detection circuit and the reference reference voltage terminal GND, not only the isolation module C1, the third voltage divider module F3 and the signal generator Y1 are arranged in series, but also The first switch module K1, the first voltage dividing module F1 and the second voltage dividing module F2.
  • a first sampling point S1 is provided between the first voltage dividing module F1 and the second voltage dividing module F2, a second sampling point S2 is provided between the isolation module C1 and the third voltage dividing module F3, and the third voltage dividing module is
  • a third sampling point S3 is provided between F3 and the signal generator Y1, and the processor P1 can be based on the first sampling signal provided by the first sampling point S1, the second sampling signal provided by the second sampling point S2, and the third sampling point S3.
  • the third sampling signal is provided, and the insulation resistance value RP of the positive high-voltage circuit on the side of the battery under test relative to the reference reference voltage terminal GND is detected and the insulation resistance of the negative high voltage circuit on the side of the battery under test relative to the reference reference voltage terminal GND is detected.
  • Value RN so as to realize the independent alarm of high pressure positive to ground pressure and high pressure negative to low pressure ground, avoiding the risk of false alarms.
  • the insulation detection circuit in the embodiment of this application is additionally provided with a first switch module K1, a first voltage divider module F1, and a second voltage divider module F2, it can be detected
  • the voltage dividing module F3 may be composed of components. The following will illustrate the specific structures of the first switch module K1, the first voltage dividing module F1, the second voltage dividing module F2, the isolation module C1, and the third voltage dividing module F3.
  • the first switching module K1 includes a first switching device
  • the first voltage dividing module F1 includes a first resistor network R1
  • the second voltage dividing module F2 includes a second resistor network R2
  • the first sampling point S1 is located at the first Between the resistance network R1 and the second resistance network R2.
  • the first switching device may be a relay, an IGBT, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), etc., and the on-off state of the first switching device may be determined by the processor P1 or other Control equipment control, not limited here.
  • MOSFET Metal-Oxide-Semiconductor Field-Effect Transistor
  • the first resistor network R1 and the second resistor network R2 play the role of voltage divider.
  • the positions of the first switching device and the first resistor network R1 and the second resistor network R2 are adjustable.
  • the first resistor network R1 and the second resistor network can be adjusted.
  • the resistance value of the network R2 adjusts the variation range of the first sampling signal obtained from the first sampling point S1.
  • the first sampling signal can be obtained from the first sampling point S1 by controlling the first switching device to turn on, the positive switch module K+ to turn off, and the negative switch module K- to turn off.
  • the isolation module C1 includes a first capacitor
  • the third voltage divider module F3 includes a third resistor network R3
  • the second sampling point S2 is located between the first capacitor and the third resistor network R3
  • the third sampling point S3 is located Between the third resistor network R3 and the signal generator Y1.
  • the third resistor network R3 plays a role of voltage divider.
  • the second sampling signal obtained from the second sampling point S2 and the third sampling signal obtained from the third sampling point S3 can be adjusted by adjusting the resistance of the third resistor network R3.
  • the first switching device can be controlled to open, the positive switch module K+ is closed, and the negative switch module K- is closed, and the second sampling signal is obtained from the second sampling point S2 and the third sampling signal is obtained from the third sampling point S3.
  • the insulation detection circuit further includes a first voltage follower G1 and a second voltage follower G2.
  • the first input terminal of the first voltage follower G1 is connected to the second sampling point S2, the second input terminal of the first voltage follower G1 is connected to the output terminal of the first voltage follower G1, and the first voltage follower G1
  • the output terminal of the second voltage follower G2 is also connected to the processor P1; the first input terminal of the second voltage follower G2 is connected to the third sampling point S3, and the second input terminal of the second voltage follower G2 is connected to the output terminal of the second voltage follower G2 Connected, the output terminal of the second voltage follower G2 is also connected to the processor P1.
  • the voltage follower shown in Figure 2 is composed of an operational amplifier. Because the sine wave voltage is relatively high and exceeds the sampling range of the processor P1, the voltage signal needs to be divided and resampled. Because the insulation resistance is generally large, it is directly The use of resistor divider will lead to shunting and make the sampling inaccurate. Using a voltage follower can increase the input impedance and improve the sampling accuracy, while also playing a filtering role.
  • the insulation detection circuit shown in Figure 2 also includes a first filter module, a second filter module, and a third filter module, which are used to filter out high-frequency interference caused by the high-frequency switching of the inverter during the driving of the electric vehicle, High-frequency interference will cause higher voltage fluctuations between the isolation capacitor and the sampling resistor, which exceeds the range of the sampling unit.
  • the first end of the first filter module is connected to the first sampling point S1, the second end of the first filter module is connected to the processor P1; the first end of the second filter module is connected to the second sampling point S2, and the second end of the second filter module is connected to the second sampling point S2.
  • the second end of the filter module is connected to the first input end of the first voltage follower G1; the first end of the third filter module is connected to the third sampling point S3, and the second end of the third filter module is connected to the second voltage follower
  • the first input terminal of G2 is connected.
  • first filter module the second filter module
  • FIG. 3 is a schematic flowchart of a detection method of an insulation detection circuit provided by an embodiment of the application. As shown in FIG. 3, the detection method includes step 301 to step 303.
  • step 301 control the positive switch module K+ to open, the negative switch module K- to open, and the first switch module K1 to close.
  • Figure 4 is an equivalent circuit diagram of the insulation detection circuit when the positive switch module K+ is off, the negative switch module K- is off, and the first switch module K1 is closed.
  • the first sampling signal U1 is obtained at point S1.
  • step 302 the positive switch module K+ is turned off, the negative switch module K- is turned off, and the first switch module K1 is turned off.
  • Figure 5 is an equivalent circuit diagram of the insulation detection circuit when the positive switch module K+ is off, the negative switch module K- is off, and the first switch module K1 is off according to an embodiment of the application.
  • the second sampling signal U2 is obtained at the sampling point S2, and the third sampling signal U3 is obtained from the third sampling point S3.
  • step 303 according to the first sampling signal U1, the second sampling signal U2, and the third sampling signal U3, the insulation resistance value RP of the positive high-voltage circuit on the side of the battery under test relative to the reference voltage terminal GND and the battery under test are calculated The insulation resistance RN of the negative high-voltage circuit on the side of the group relative to the reference voltage terminal GND.
  • FIG. 6 is a schematic flowchart of a detection method of an insulation detection circuit provided by another embodiment of the application. The difference between FIG. 6 and FIG. 3 is that step 303 in FIG. 3 can be refined into step 3031 and step 3032 in FIG. 6.
  • step 3031 according to the second sampling signal U2 and the third sampling signal U3, the first parallel resistance value Rnp is obtained.
  • the first parallel resistance value Rnp is the difference between the positive high voltage circuit on the side of the battery pack under test and the reference voltage terminal GND.
  • FIG. 7 is an equivalent circuit diagram of the insulation detection circuit corresponding to Figure 5.
  • the capacitance value after being connected in parallel with the negative capacitor CN, namely Cnp CN//CP, the equivalent insulation resistance value Rnp is smaller than RN and RP.
  • Those skilled in the art can refer to the relevant technical data, according to the second sampling The amplitude and phase shift of the signal U2 and the third sampling signal U3 obtain the first parallel resistance value Rnp, which will not be repeated here.
  • step 3032 according to the first sampling signal U1 and the first parallel resistance value Rnp, the insulation resistance value RP of the positive high voltage circuit on the side of the battery under test relative to the reference reference voltage terminal GND and the negative high voltage on the side of the battery under test are obtained.
  • Ubat is the voltage at both ends of the battery pack.
  • the insulation resistance values of RP and RN can be calculated.
  • the long hanging branch composed of the first resistor network R1, the second resistor network R2, and the first switch module K1 it is possible to avoid the inaccurate sampling of the insulation resistance due to the interference of the entire vehicle, which may cause the insulation error of the entire vehicle.
  • the problem with the alarm In specific implementation, if the measured insulation resistance of the whole vehicle is too low, it will be incorporated into the first resistance network R1 and the second resistance network R2 before performing insulation sampling. If the calculated insulation resistance of the whole vehicle is greater than the alarm value, then It is believed that a false detection has occurred.
  • FIG. 8 is a schematic flowchart of a detection method of an insulation detection circuit provided by another embodiment of the application. The difference between FIG. 8 and FIG. 3 is that step 302 in FIG. 3 can be refined into steps 3021 to 3024 in FIG. 8.
  • step 3021 control the positive switch module K+ to close, the negative switch module K- to close, and the first switch module K1 to open.
  • FIG. 9 is an equivalent circuit diagram of the insulation detection circuit when the positive switch module K+ is closed, the negative switch module K- is closed, and the first switch module K1 is disconnected according to an embodiment of the application.
  • the fourth sampling signal U4 is obtained from the second sampling point S2
  • the fifth sampling signal U5 is obtained from the third sampling point S3.
  • the second parallel resistance value Rnpuwv is obtained.
  • the second parallel resistance value Rnpuwv is the value of the positive high voltage circuit on the side of the battery pack under test relative to the reference reference voltage terminal GND.
  • Those skilled in the art can refer to relevant technical materials to obtain the second parallel resistance value Rnpuwv according to the amplitude and phase shift of the second sampling signal U2 and the third sampling signal U3, which will not be repeated here.
  • step 3023 it is determined whether the second parallel resistance value Rnpuwv is less than the first alarm threshold.
  • step 3024 if the second parallel resistance Rnpuwv is less than the first alarm threshold, the positive switch module K+ is controlled to be disconnected, the negative switch module K- is disconnected, and the first switch module K1 is disconnected, that is, the motor controller is requested to be disconnected ,
  • the equivalent circuit structure in FIG. 5 is obtained, the second sampling signal U2 is obtained from the second sampling point S2, the third sampling signal U3 is obtained from the third sampling point S3, and Rnp is calculated.
  • FIG. 10 is a schematic flowchart of a detection method of an insulation detection circuit provided by still another embodiment of the application. The difference between FIG. 10 and FIG. 3 is that after step 302 in FIG. 3, the detection method further includes steps 304 to 307 in FIG. 10.
  • step 304 the first parallel resistance value Rnp is obtained according to the second sampling signal U2 and the third sampling signal U3.
  • a third parallel resistance value Ruwv is obtained, that is, the parallel resistance value of the insulation resistance of the three-phase end of the vehicle.
  • step 306 if the third parallel resistance Ruwv is less than the second alarm threshold, it is determined that the insulation resistance of the three-phase terminal on the side where the load is located fails.
  • step 307 if the third parallel resistance Ruwv is greater than the second alarm threshold, it is determined that the insulation resistance of the side where the battery pack to be tested is located has failed.
  • the technical solutions in the embodiments of the present application are suitable for insulation resistance detection in power vehicles, and can distinguish which section of the battery pack high-voltage system has a low insulation resistance to ground.
  • the insulation resistance of the three-phase end of the vehicle By comparing the parallel resistance value of the vehicle with the alarm threshold of the insulation resistance of the vehicle, it can be determined whether the insulation resistance of the AC end of the vehicle is abnormal or abnormal; when the insulation resistance of the DC
  • the insulation resistance value RP of the positive high voltage circuit relative to the reference reference voltage terminal GND, and the insulation resistance value RN of the negative high voltage circuit on the side of the battery under test relative to the reference reference voltage terminal GND are respectively compared with the corresponding alarm thresholds, which can be distinguished as high voltage positive Whether the insulation resistance value of the low voltage ground is abnormal or the high voltage negative insulation resistance value is abnormal, so as to avoid the false alarm of the insulation resistance value.
  • using the embodiments of the present application can identify single-ended insulation resistance failures and improve the stability of insulation detection.
  • fault points can be identified faster, troubleshooting efficiency can be improved, and insulation resistance can be quickly located The location of the fault improves after-sales guarantee and maintenance quality.
  • An embodiment of the present application also provides a battery management system.
  • the battery management system includes the above-mentioned insulation detection circuit.
  • the insulation detection circuit may be an independent circuit structure or a part of the overall circuit structure.
  • the insulation detection circuit in the embodiment of the present application may be integrated in the battery management system of the battery pack, or a part of the overall circuit structure of the battery management system may be used for insulation detection.

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Abstract

一种绝缘检测电路及检测方法、电池管理***，该绝缘检测电路包括：第一开关模块（K1），第一分压模块（F1）、第二分压模块（F2）、隔离模块（C1）、第三分压模块（F3）、信号发生器（Y1）和处理器（P1）；其中，第一开关模块（K1）、第一分压模块（F1）和第二分压模块（F2）串联设置于待测电池组的正极和参考基准电压端（GND）之间；隔离模块（C1）、第三分压模块（F3）和信号发生器（Y1）串联设置于待测电池组的正极和参考基准电压端（GND）之间。采用方法，能够单独检测到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值，从而能够实现高压正对地压低以及高压负对低压地的独立报警，避免出现误报警的风险。

Description

绝缘检测电路及检测方法、电池管理***
相关申请的交叉引用
本申请要求享有于2019年03月01日提交的名称为“绝缘检测电路及检测方法、电池管理***”的中国专利申请第201910156503.0号的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，具体涉及一种绝缘检测电路及检测方法、电池管理***。
背景技术
电池组负责为电动汽车的电动机提供电能，电池组分别通过正极开关模块和负极开关模块与负载连接。电池组作为电动汽车的关键部件之一，其高压电的安全性是动力电池***的首要考虑对象，因此，对电动汽车绝缘性能的检测是设计中必不可少的一部分，也就是说，提前检测并发出绝缘异常的预警变得尤为重要。
发明内容
本申请的目的是提供一种绝缘检测电路及检测方法、电池管理***，所述绝缘检测电路能够单独检测到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值，从而实现高压正对地压低以及高压负对低压地的独立报警，避免出现误报警的风险。
一方面，本申请实施例提供了一种绝缘检测电路，该绝缘检测电路包括：第一开关模块，第一分压模块、第二分压模块、隔离模块、第三分压模块、信号发生器和处理器；其中，
第一开关模块、第一分压模块和第二分压模块串联设置于待测电池组的正极和参考基准电压端之间；
隔离模块、第三分压模块和信号发生器串联设置于待测电池组的正极和参考基准电压端之间；
第一分压模块和第二分压模块之间设置有第一采样点，隔离模块和第三分压模块之间设置有第二采样点，第三分压模块和信号发生器之间设置有第三采样点；
第一采样点被配置为提供第一采样信号，第二采样点被配置为提供第二采样信号，第三采样点配置为提供第三采样信号；
处理器被配置为根据第一采样信号、第二采样信号和第三采样信号，计算待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值。
在第一方面的一种可能的实施方式中，第一开关模块包括第一开关器件，第一分压模块包括第一电阻网络，第二分压模块包括第二电阻网络，第一采样点位于第一电阻网络和第二电阻网络之间。
在第一方面的一种可能的实施方式中，隔离模块包括第一电容，第三分压模块包括第三电阻网络，第二采样点位于第一电容和第三电阻网络之间，第三采样点位于第三电阻网络和信号发生器之间。
在第一方面的一种可能的实施方式中，绝缘检测电路还包括第一电压跟随器和第二电压跟随器；其中，第一电压跟随器的第一输入端与第二采样点连接，第一电压跟随器的第二输入端与第一电压跟随器的输出端连接，第一电压跟随器的输出端还与处理器连接；第二电压跟随器的第一输入端与第三采样点连接，第二电压跟随器的第二输入端与第二电压跟随器的输出端连接，第二电压跟随器的输出端还与处理器连接。
在第一方面的一种可能的实施方式中，绝缘检测电路还包括：第一滤波模块、第二滤波模块和第三滤波模块；其中，第一滤波模块的第一端与第一采样点连接，第一滤波模块的第二端与处理器连接；第二滤波模块的第一端与第二采样点连接，第二滤波模块的第二端与第一电压跟随器的第一输入端连接；第三滤波模块的第一端与第三采样点连接，第三滤波模块 的第二端与第二电压跟随器的第一输入端连接。
在第一方面的一种可能的实施方式中，绝缘检测电路还包括第一电压跟随器和第二电压跟随器；其中，第一电压跟随器的第一输入端与第二采样点连接，第一电压跟随器的第二输入端与第一电压跟随器的输出端连接，第一电压跟随器的输出端还与处理器连接；第二电压跟随器的第一输入端与第三采样点连接，第二电压跟随器的第二输入端与第二电压跟随器的输出端连接，第二电压跟随器的输出端还与处理器连接。
第二方面，本申请实施例提供一种电池管理***，该电池管理***包括如上所述的绝缘检测电路。
第三方面，本申请实施例提供一种绝缘检测电路的检测方法，用于如上所述的绝缘检测电路，该检测方法包括：
控制位于待测电池组的正极和负载之间的正极开关模块断开、位于待测电池组的负极和负载之间的负极开关模块断开、第一开关模块闭合，从第一采样点获得第一采样信号；
控制正极开关模块断开、负极开关模块断开、第一开关模块断开，从第二采样点获得第二采样信号，并从第三采样点获得第三采样信号；
根据第一采样信号、第二采样信号和第三采样信号，计算待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值。
在第二方面的一种可能的实施方式中，根据第一采样信号、第二采样信号和第三采样信号，计算待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值，包括：根据第二采样信号和第三采样信号，得到第一并联阻值，第一并联阻值为待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值的并联阻值；根据第一采样信号和第一并联阻值，得到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值。
在第二方面的一种可能的实施方式中，控制正极开关模块断开、负极 开关模块断开、第一开关模块断开，从第二采样点获得第二采样信号，并从第三采样点获得第三采样信号，包括：控制正极开关模块闭合、负极开关模块闭合，第一开关模块断开，从第二采样点获得第四采样信号，并从第三采样点获得第五采样信号；根据第四采样信号和第五采样信号，得到第二并联阻值，第二并联阻值为待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值、待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值以及整车三相端绝缘阻值的并联阻值；判断第二并联阻值是否小于第一报警阈值；若第二并联阻值小于第一报警阈值，则控制正极开关模块断开、负极开关模块断开、第一开关模块断开，从第二采样点获得第二采样信号，并从第三采样点获得第三采样信号。
在第二方面的一种可能的实施方式中，在从第二采样点获得第二采样信号，并从第三采样点获得第三采样信号之后，该检测方法还包括：根据第二采样信号和第三采样信号，得到第一并联阻值，第一并联阻值为待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值的并联阻值；根据第一并联阻值和第二并联阻值，得到第三并联阻值，第三并联阻值为整车三相端绝缘阻值的并联阻值；若第三并联阻值小于第二报警阈值，则确定负载所在侧三相端绝缘阻值发生故障；若第三并联阻值大于第二报警阈值，则确定待测电池组所在侧绝缘阻值发生故障。
在本申请实施例中，绝缘检测电路的待测电池组的正极和参考基准电压端之间，不仅串联设置有隔离模块、第三分压模块和信号发生器，而且串联设置有第一开关模块、第一分压模块和第二分压模块。其中，第一分压模块和第二分压模块之间设置有第一采样点，隔离模块和第三分压模块之间设置有第二采样点，第三分压模块和信号发生器之间设置有第三采样点，处理器能够根据第一采样点提供的第一采样信号、第二采样点提供的第二采样信号和第三采样点提供的第三采样信号，检测得到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值，从而实现高压正对地压低以及高压负对低压地的独立报警，避免出现误报警的风险。
与现有技术中的交流注入法不同，由于本申请实施例中的绝缘检测电路，增设有第一开关模块、第一分压模块和第二分压模块，因此，能够在检测得到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值的并联阻值的基础上，进一步单独检测得到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值。
附图说明
下面将参考附图来描述本申请示例性实施例的特征、优点和技术效果，其中的附图并未按照实际的比例绘制。
图1是本申请一实施例提供的绝缘检测电路的结构示意图；
图2为本申请另一实施例提供的绝缘检测电路的结构示意图；
图3为本申请一个实施例提供的绝缘检测电路的检测方法的流程示意图；
图4为本申请实施例提供的正极开关模块断开、负极开关模块断开、第一开关模块闭合时绝缘检测电路的等效电路图；
图5为本申请实施例提供的正极开关模块断开、负极开关模块断开、第一开关模块断开时绝缘检测电路的等效电路图；
图6为本申请另一实施例提供的绝缘检测电路的检测方法的流程示意图；
图7为与图5对应的绝缘检测电路的等效电路图；
图8为本申请又一实施例提供的绝缘检测电路的检测方法的流程示意图；
图9为本申请实施例提供的正极开关模块闭合、负极开关模块闭合、第一开关模块断开时绝缘检测电路的等效电路图；
图10为本申请再一实施例提供的绝缘检测电路的检测方法的流程示意图。
具体实施方式
下面将详细描述本申请的各个方面的特征和示例性实施例。在下面的详细描述中，提出了许多具体细节，以便提供对本申请的全面理解。
目前，主要基于交流注入法或者分压法对电池组进行绝缘检测，但是，交流注入法或者分压法只能检测到整车高压正对低压地以及高压负对低压地的绝缘阻值的并联值，当整车高压正对低压地绝缘阻值较低，高压负对低压地绝缘阻值同时较低时，可能高压正对低压地和高压负对低压地绝缘阻值大于报警阈值，但两者并联值却小于报警阈值，因此，会出现误报警的风险。
本申请实施例提供了一种绝缘检测电路及检测方法、电池管理***，采用本申请实施例中的技术方案，能够单独检测到待测电池组所在侧正极高压电路相对于参考基准电压端的绝缘阻值(即高压正对低压地的绝缘阻值)和待测电池组所在侧负极高压电路相对于参考基准电压端的绝缘阻值(即高压负对低压地的绝缘阻值)，从而实现高压正对地压低以及高压负对低压地的独立报警，避免出现误报警的风险。
本申请实施例中的待测电池组可以为锂离子电池、锂金属电池、铅酸电池、镍隔电池、镍氢电池、锂硫电池、锂空气电池或者钠离子电池，在此不做限定。从规模而言，待测电池组也可以为电芯单体，也可以是电池模组或电池包，在此不做限定。
图1为本申请一实施例提供的绝缘检测电路的结构示意图。如图1所示，该绝缘检测电路包括：第一开关模块K1，第一分压模块F1、第二分压模块F2、隔离模块C1、第三分压模块F3、信号发生器Y1和处理器P1。
其中，第一开关模块K1、第一分压模块F1和第二分压模块F2串联设置于待测电池组的正极和参考基准电压端GND之间。第一开关模块K1、第一分压模块F1和第二分压模块F2的顺序可调，且第一分压模块F1和第二分压模块F2之间设置有第一采样点S1，第一采样点S1被配置为提供第一采样信号。
隔离模块C1、第三分压模块F3和信号发生器Y1串联设置于待测电池组的正极和参考基准电压端GND之间。其中，隔离模块C1和第三分压模 块F3之间设置有第二采样点S2，第二采样点S2被配置为提供第二采样信号；第三分压模块F3和信号发生器Y1之间设置有第三采样点S3，第三采样点S3被配置为提供第三采样信号。
处理器P1被配置为根据第一采样信号、第二采样信号和第三采样信号，计算待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP，和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN。处理器P1可以是专用于绝缘检测电路的处理器P1，也可以为与其他的电路共用的处理器P1。
图1中还示出了CP、CN、Q1～Q6、Ru、Rv和Rw，其中，CP和CN分别为待测电池组的正极、负极与其壳体之间的等效电容，Q1～Q6为全桥功率单元，用于将待测电池组的直流电压转变为负载(比如电动机)所需的三相电压，Ru、Rv和Rw分别为三相支路与整车车体之间的等效绝缘阻值，Cx为X电容。
图1中还示出了正极开关模块K+和负极开关模块K-，正极开关模块K+和负极开关模块K-可以理解为位于待测电池组与负载用电回路之间的开关器件，比如，继电器、绝缘栅双极型晶体管IGBT(Insulated Gate Bipolar Transistor，IGBT)等，正极开关模块K+和负极开关模块K-的通断状态可以由处理器P1或其他控制设备进行控制，此处不做限定。
图1中还示出了参考基准电压端GND，参考基准电压端GND的实际电压可以根据绝缘检测电路的工作场景以及需求进行设定，在一示例中，参考基准电压端GND可以为电池组的壳体。
示例性地，信号发生器Y1可以为直接数字式频率合成器(Direct Digital Synthesizer，DDS)，用于生成一个频率稳定可调、输出电压幅值较小的交流源信号，该交流源信号注入检测回路之后，再采集信号源电压的幅值信号(即第二采样点S2的采样信号)，以及隔离模块C1与第三分压模块F3之间的幅值信号(即第三采样点S3的采样信号)。
在本申请实施例中，绝缘检测电路的待测电池组的正极和参考基准电压端GND之间，不仅串联设置有隔离模块C1、第三分压模块F3和信号发生器Y1，而且串联设置有第一开关模块K1、第一分压模块F1和第二分压 模块F2。其中，第一分压模块F1和第二分压模块F2之间设置有第一采样点S1，隔离模块C1和第三分压模块F3之间设置有第二采样点S2，第三分压模块F3和信号发生器Y1之间设置有第三采样点S3，处理器P1能够根据第一采样点S1提供的第一采样信号、第二采样点S2提供的第二采样信号和第三采样点S3提供的第三采样信号，检测得到待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN，从而实现高压正对地压低以及高压负对低压地的独立报警，避免出现误报警的风险。
与现有技术中的交流注入法不同，由于本申请实施例中的绝缘检测电路，增设有第一开关模块K1、第一分压模块F1和第二分压模块F2，因此，能够在检测得到待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN的并联阻值RP//RN的基础上，进一步单独检测得到待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN。
图2为本申请另一实施例提供的绝缘检测电路的结构示意图，如图2所示，第一开关模块K1，第一分压模块F1、第二分压模块F2、隔离模块C1和第三分压模块F3可以由元器件组成，下面将举例说明第一开关模块K1，第一分压模块F1、第二分压模块F2、隔离模块C1和第三分压模块F3的具体结构。
在一示例中，第一开关模块K1包括第一开关器件，第一分压模块F1包括第一电阻网络R1，第二分压模块F2包括第二电阻网络R2，第一采样点S1位于第一电阻网络R1和第二电阻网络R2之间。
其中，第一开关器件可以为继电器、IGBT、金属-氧化物半导体场效应晶体管(Metal-Oxide-Semiconductor Field-Effect Transistor,MOSFET)等，第一开关器件的通断状态可以由处理器P1或其他控制设备控制，此处不做限定。
第一电阻网络R1和第二电阻网络R2起到分压作用，第一开关器件和 第一电阻网络R1和第二电阻网络R2的位置可调，可通过调整第一电阻网络R1和第二电阻网络R2的阻值大小，调整从第一采样点S1得到的第一采样信号的变化范围。具体实施时，可以通过控制第一开关器件闭合、正极开关模块K+断开、负极开关模块K-断开，从第一采样点S1得到第一采样信号。
在一示例中，隔离模块C1包括第一电容，第三分压模块F3包括第三电阻网络R3，第二采样点S2位于第一电容和第三电阻网络R3之间，第三采样点S3位于第三电阻网络R3和信号发生器Y1之间。
其中，第三电阻网络R3起到分压作用，可通过调整第三电阻网络R3的阻值大小，调整从第二采样点S2得到的第二采样信号和从第三采样点S3得到的第三采样信号的变化范围。具体实施时，可以控制第一开关器件断开、正极开关模块K+闭合、负极开关模块K-闭合，从第二采样点S2得到第二采样信号并从第三采样点S3得到第三采样信号。
在一示例中，如图2所示，绝缘检测电路还包括第一电压跟随器G1和第二电压跟随器G2。其中，第一电压跟随器G1的第一输入端与第二采样点S2连接，第一电压跟随器G1的第二输入端与第一电压跟随器G1的输出端连接，第一电压跟随器G1的输出端还与处理器P1连接；第二电压跟随器G2的第一输入端与第三采样点S3连接，第二电压跟随器G2的第二输入端与第二电压跟随器G2的输出端连接，第二电压跟随器G2的输出端还与处理器P1连接。
图2中示出的电压跟随器由运算放大器构成，由于正弦波电压比较高，超过了处理器P1的采样范围，因此需要将电压信号进行分压再采样，由于绝缘阻值一般比较大，直接采用电阻分压会导致分流，使得采样不准，采用电压跟随器能够增大输入阻抗，提高采样精度，同时还能够起到滤波作用。
图2中示出的绝缘检测电路还包括第一滤波模块、第二滤波模块和第三滤波模块，用于滤除电动汽车在行驶过程中由于逆变器的高频切换导致的高频干扰，高频干扰会导致隔离电容与采样电阻之间产生较高电压的波动，超出采样单元的量程。
其中，第一滤波模块的第一端与第一采样点S1连接，第一滤波模块的第二端与处理器P1连接；第二滤波模块的第一端与第二采样点S2连接，第二滤波模块的第二端与第一电压跟随器G1的第一输入端连接；第三滤波模块的第一端与第三采样点S3连接，第三滤波模块的第二端与第二电压跟随器G2的第一输入端连接。
图2中示出的第一滤波模块、第二滤波模块和第三滤波模块的具体实现形式为RC滤波电路，本领域技术人员也可以选用其他结构的滤波电路，此处不进行限定。
下面举例说明本申请实施例中的绝缘检测电路的检测方法。
图3为本申请一个实施例提供的绝缘检测电路的检测方法的流程示意图。如图3所示，该检测方法包括步骤301至步骤303。
在步骤301中，控制正极开关模块K+断开、负极开关模块K-断开、第一开关模块K1闭合。参阅图4，图4为本申请实施例提供的正极开关模块K+断开、负极开关模块K-断开、第一开关模块K1闭合时绝缘检测电路的等效电路图，此时，从第一采样点S1获得第一采样信号U1。
在步骤302中，控制正极开关模块K+断开、负极开关模块K-断开、第一开关模块K1断开。参阅图5，图5为本申请实施例提供的正极开关模块K+断开、负极开关模块K-断开、第一开关模块K1断开时绝缘检测电路的等效电路图，此时，从第二采样点S2获得第二采样信号U2，并从第三采样点S3获得第三采样信号U3。
在步骤303中，根据第一采样信号U1、第二采样信号U2和第三采样信号U3，计算待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN。
图6为本申请另一实施例提供的绝缘检测电路的检测方法的流程示意图。图6与图3的不同之处在于，图3中的步骤303可细化为图6中的步骤3031和步骤3032。
在步骤3031中，根据第二采样信号U2和第三采样信号U3，得到第一并联阻值Rnp，第一并联阻值Rnp为待测电池组所在侧正极高压电路相对 于参考基准电压端GND的绝缘阻值和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值的并联阻值。
参阅图7，图7为与图5对应的绝缘检测电路的等效电路图，Rnp为正极绝缘电阻RP和负极绝缘电阻RN并联后的阻值，即Rnp＝RN//RP，Cnp为正极电容CP和负极电容CN并联后的容值，即Cnp＝CN//CP，等效后的绝缘阻值Rnp相对于RN和RP而言更小，本领域技术人员可以参考相关技术资料，根据第二采样信号U2和第三采样信号U3的幅值和相移，得到第一并联阻值Rnp，此处不进行赘述。
在步骤3032中，根据第一采样信号U1和第一并联阻值Rnp，得到待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP和待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN。
具体地，结合图4中的等效电路结构，可以将U1和Rnp代入公式(1)-公式(3)，其中，公式(1)-公式(3)根据基尔霍夫定律得到：
Figure PCTCN2020077269-appb-000001
Figure PCTCN2020077269-appb-000002
Figure PCTCN2020077269-appb-000003
其中，Ubat为电池组两端的电压，联立公式(1)(2)(3)，可计算得到RP及RN的绝缘阻值。
如上所述，通过增加第一电阻网络R1、第二电阻网络R2和第一开关模块K1组成的长挂支路，能够避免由于整车的干扰导致绝缘阻值采样不准而导致整车绝缘误报警的问题。具体实施时，如果测量到整车绝缘阻值过低，就并入第一电阻网络R1和第二电阻网络R2后再进行绝缘采样，若计算得到后的整车绝缘阻值大于报警值，则认为产生了误检。
图8为本申请又一实施例提供的绝缘检测电路的检测方法的流程示意图。图8与图3的不同之处在于，图3中的步骤302可细化为图8中的步骤3021至步骤3024。
在步骤3021中，控制正极开关模块K+闭合、负极开关模块K-闭合、 第一开关模块K1断开。参阅图9，图9为本申请实施例提供的正极开关模块K+闭合、负极开关模块K-闭合、第一开关模块K1断开时绝缘检测电路的等效电路图。此时，从第二采样点S2获得第四采样信号U4，并从第三采样点S3获得第五采样信号U5。
在步骤3022中，根据第四采样信号U4和第五采样信号U5，得到第二并联阻值Rnpuwv，第二并联阻值Rnpuwv为待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP、待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN以及整车三相端绝缘阻值(Ru、Rw和Rv)的并联阻值。本领域技术人员可以参考相关技术资料，根据第二采样信号U2和第三采样信号U3的幅值和相移，得到第二并联阻值Rnpuwv，此处不进行赘述。
在步骤3023中，判断第二并联阻值Rnpuwv是否小于第一报警阈值。
在步骤3024中，若第二并联阻值Rnpuwv小于第一报警阈值，则控制正极开关模块K+断开、负极开关模块K-断开以及第一开关模块K1断开，即请求断开电动机控制器，得到图5中的等效电路结构，并从第二采样点S2获得第二采样信号U2，从第三采样点S3获得第三采样信号U3，计算得到Rnp。
图10为本申请再一实施例提供的绝缘检测电路的检测方法的流程示意图。图10与图3的不同之处在于，在图3中的步骤302之后，该检测方法还包括图10中的步骤304至步骤307。
在步骤304中，根据第二采样信号U2和第三采样信号U3，得到第一并联阻值Rnp。
在步骤305中，根据第一并联阻值Rnp和第二并联阻值Rnpuwv，得到第三并联阻值Ruwv，即整车三相端绝缘阻值的并联阻值。
在步骤306中，若第三并联阻值Ruwv小于第二报警阈值，则确定负载所在侧三相端绝缘阻值发生故障。
在步骤307中，若第三并联阻值Ruwv大于第二报警阈值，则确定待测电池组所在侧绝缘阻值发生故障。
如上所述，本申请实施例中的技术方案适用于动力车辆中绝缘电阻检 测，能够区分出电池组高压***中哪一段对地的绝缘阻值偏低，比如，将整车三相端绝缘阻值的并联阻值与整车绝缘阻值的报警阈值进行比较，可以确定整车交流端的绝缘阻值是异常还是直流端异常；当直流端绝缘阻值异常时，通过将待测电池组所在侧正极高压电路相对于参考基准电压端GND的绝缘阻值RP、待测电池组所在侧负极高压电路相对于参考基准电压端GND的绝缘阻值RN分别与对应报警阈值进行比较，能够区分是高压正对低压地绝缘阻值异常还是高压负对地绝缘阻值异常，从而避免产生绝缘阻值误报的情况。
另外，采用本申请实施例能够识别单端绝缘阻值失效，提高绝缘检测的稳定性，通过识别单端RP或者RN故障，能够更快地识别故障点，提高故障排查效率，快速定位绝缘阻值故障的位置，提升售后保障维护质量。
本申请实施例还提供一种电池管理***，该电池管理***包括如上所述绝缘检测电路，该绝缘检测电路可以是独立的电路结构，也可以是整体电路结构的一部分。示例性地，本申请实施例中的绝缘检测电路可以集成在电池组的电池管理***中，也可以是将电池管理***的整体电路结构中的一部分用作绝缘检测。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (10)

  1. 一种绝缘检测电路，其中，包括：第一开关模块、第一分压模块、第二分压模块、隔离模块、第三分压模块、信号发生器和处理器；其中，
    所述第一开关模块、所述第一分压模块和所述第二分压模块串联设置于待测电池组的正极和参考基准电压端之间；
    所述隔离模块、所述第三分压模块和所述信号发生器串联设置于所述待测电池组的正极和所述参考基准电压端之间；
    所述第一分压模块和所述第二分压模块之间设置有第一采样点，所述隔离模块和所述第三分压模块之间设置有第二采样点，所述第三分压模块和所述信号发生器之间设置有第三采样点；
    所述第一采样点被配置为提供第一采样信号，所述第二采样点被配置为提供第二采样信号，所述第三采样点配置为提供第三采样信号；
    所述处理器被配置为根据所述第一采样信号、所述第二采样信号和所述第三采样信号，计算所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值和所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值。
  2. 根据权利要求1所述的绝缘检测电路，其中，所述第一开关模块包括第一开关器件，所述第一分压模块包括第一电阻网络，所述第二分压模块包括第二电阻网络，所述第一采样点位于所述第一电阻网络和所述第二电阻网络之间。
  3. 根据权利要求1所述的绝缘检测电路，其中，所述隔离模块包括第一电容，所述第三分压模块包括第三电阻网络，所述第二采样点位于所述第一电容和所述第三电阻网络之间，所述第三采样点位于所述第三电阻网络和所述信号发生器之间。
  4. 根据权利要求1所述的绝缘检测电路，其中，所述绝缘检测电路还包括第一电压跟随器和第二电压跟随器；其中，
    所述第一电压跟随器的第一输入端与所述第二采样点连接，第一电压跟随器的第二输入端与所述第一电压跟随器的输出端连接，所述第一电压跟随器的输出端还与所述处理器连接；
    所述第二电压跟随器的第一输入端与所述第三采样点连接，第二电压跟随器的第二输入端与所述第二电压跟随器的输出端连接，所述第二电压跟随器的输出端还与所述处理器连接。
  5. 根据权利要求4所述的绝缘检测电路，其中，所述绝缘检测电路还包括：第一滤波模块、第二滤波模块和第三滤波模块；其中，
    所述第一滤波模块的第一端与所述第一采样点连接，所述第一滤波模块的第二端与所述处理器连接；
    所述第二滤波模块的第一端与所述第二采样点连接，所述第二滤波模块的第二端与所述第一电压跟随器的第一输入端连接；
    所述第三滤波模块的第一端与所述第三采样点连接，所述第三滤波模块的第二端与所述第二电压跟随器的第一输入端连接。
  6. 一种电池管理***，其中，包括如权利要求1-5任一项所述的绝缘检测电路。
  7. 一种绝缘检测电路的检测方法，其中，用于如权利要求1-5任一项所述的绝缘检测电路，所述方法包括：
    控制位于所述待测电池组的正极和负载之间的正极开关模块断开、位于所述待测电池组的负极和负载之间的负极开关模块断开、所述第一开关模块闭合，从所述第一采样点获得第一采样信号；
    控制所述正极开关模块断开、所述负极开关模块断开、所述第一开关模块断开，从所述第二采样点获得第二采样信号，并从所述第三采样点获得第三采样信号；
    根据所述第一采样信号、所述第二采样信号和所述第三采样信号，计算所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值和所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值。
  8. 根据权利要求7所述的方法，其中，所述根据所述第一采样信号、所述第二采样信号和所述第三采样信号，计算所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值和所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值，包括：
    根据所述第二采样信号和所述第三采样信号，得到第一并联阻值，所述第一并联阻值为所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值和所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值的并联阻值；
    根据所述第一采样信号和所述第一并联阻值，得到所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值和所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值。
  9. 根据权利要求7所述的方法，其中，所述控制所述正极开关模块断开、所述负极开关模块断开、所述第一开关模块断开，从所述第二采样点获得第二采样信号，并从所述第三采样点获得第三采样信号，包括：
    控制所述正极开关模块闭合、所述负极开关模块闭合，所述第一开关模块断开，从所述第二采样点获得第四采样信号，并从所述第三采样点获得第五采样信号；
    根据所述第四采样信号和所述第五采样信号，得到第二并联阻值，所述第二并联阻值为所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值、所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值以及整车三相端绝缘阻值的并联阻值；
    判断所述第二并联阻值是否小于第一报警阈值；
    若所述第二并联阻值小于所述第一报警阈值，则控制所述正极开关模块断开、所述负极开关模块断开、所述第一开关模块断开，从所述第二采样点获得第二采样信号，并从所述第三采样点获得第三采样信号。
  10. 根据权利要求7所述的方法，其中，在所述从所述第二采样点获得第二采样信号，并从所述第三采样点获得第三采样信号之后，所述方法还包括：
    根据所述第二采样信号和所述第三采样信号，得到第一并联阻值，所述第一并联阻值为所述待测电池组所在侧正极高压电路相对于所述参考基准电压端的绝缘阻值和所述待测电池组所在侧负极高压电路相对于所述参考基准电压端的绝缘阻值的并联阻值；
    根据所述第一并联阻值和所述第二并联阻值，得到第三并联阻值，所 述第三并联阻值为整车三相端绝缘阻值的并联阻值；
    若所述第三并联阻值小于第二报警阈值，则确定负载所在侧三相端绝缘阻值发生故障；
    若所述第三并联阻值大于所述第二报警阈值，则确定所述待测电池组所在侧绝缘阻值发生故障。
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