WO2020177637A1 - 电容校准电路、电容校准方法和电池管理系统 - Google Patents

电容校准电路、电容校准方法和电池管理系统 Download PDF

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WO2020177637A1
WO2020177637A1 PCT/CN2020/077262 CN2020077262W WO2020177637A1 WO 2020177637 A1 WO2020177637 A1 WO 2020177637A1 CN 2020077262 W CN2020077262 W CN 2020077262W WO 2020177637 A1 WO2020177637 A1 WO 2020177637A1
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module
sampling
circuit
capacitance
signal
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PCT/CN2020/077262
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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
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 WO2020177637A1 publication Critical patent/WO2020177637A1/zh

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/16Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line
    • G01R27/18Measuring resistance to earth, i.e. line to ground
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/3644Constructional arrangements
    • G01R31/3648Constructional arrangements comprising digital calculation means, e.g. for performing an algorithm
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R35/00Testing or calibrating of apparatus covered by the other groups of this subclass
    • G01R35/02Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating

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  • This application relates to the field of new energy, and in particular to a capacitance calibration circuit, a capacitance calibration method, and a battery management system.
  • Electric vehicles instead of fuel vehicles have become a trend in the development of the automotive industry.
  • the power battery pack is one of the key components of electric vehicles, and the safety of its high-voltage power must be one of the primary considerations of the power battery system. Therefore, the inspection of the insulation performance of electric vehicles is an essential part.
  • the current method of detecting insulation resistance is low-frequency injection.
  • the low-frequency injection method requires a capacitor module to be connected between the high-voltage side and the low-voltage side, and the sampling module needs to be connected between the capacitor module and the injected signal. Through the injection signal, the signal between the capacitor module and the sampling module, and the capacitance value of the capacitor module, etc. To calculate the insulation resistance of the vehicle.
  • the capacitance value of the capacitor module Due to factors such as materials and processes, the capacitance value of the capacitor module has a large factory error, and with the increase of the service life of the capacitor module, temperature influence and other environmental factors, the error of the capacitance value becomes larger. Since the capacitance value of the capacitor module needs to be used in the process of calculating the insulation resistance value, the error of the capacitance value will make the calculation value of the insulation resistance value too large, leading to false alarms or untimely alarms, resulting in insulation caused Dangerous, therefore, calibrating the capacitance is a problem to be solved.
  • the embodiment of the application provides a capacitance calibration circuit, a capacitance calibration method, and a battery management system, which realize the calibration of the capacitance value of the capacitance module.
  • a capacitance calibration circuit is provided, and the circuit includes:
  • one end of the first switch module is connected to the positive electrode of the power battery, and the other end of the first switch module is respectively connected to one end of the second switch module and one end of the capacitor module;
  • Capacitor module the other end of the capacitor module is connected to one end of the sampling module
  • Sampling module the other end of the sampling module is connected to one end of the signal generating module;
  • Signal generation module the other end of the signal generation module is connected to the power ground for outputting signals of predetermined frequency
  • the second switch module the other end of the second switch module is connected to the power ground;
  • the processing module is used to control the first switch module and the second switch module, and when the first switch module is in the open state and the second switch module is in the closed state, according to the first sampling signal collected from one end of the sampling module, the slave The second sampling signal and the predetermined frequency collected at one end of the signal generating module obtain the calibrated capacitance value of the capacitance module.
  • the sampling module includes a first resistor, which is respectively connected to the capacitance module and the signal generation module.
  • the processing module is specifically configured to calculate the capacitance module according to the phase shift of the first sampling signal relative to the second sampling signal, the resistance value of the sampling module, and the predetermined frequency Calibrated capacitance value.
  • the circuit further includes a resistance module connected to the second switch module.
  • the processing module is specifically configured to calculate the phase shift of the first sampling signal relative to the second sampling signal, the resistance value of the sampling module, the resistance value of the resistance module, and the The predetermined frequency is used to calculate the calibration capacitance value of the capacitance module.
  • the resistance module includes:
  • a second resistor one end of the second resistor is connected to the other end of the first switch module, and the other end of the second resistor is connected to the second switch module;
  • the third resistor is arranged between the second switch module and the power ground.
  • the circuit further includes:
  • the first sampling circuit the first end of the first sampling circuit is connected to one end of the sampling module, the second end of the first sampling circuit is connected to the processing module, and the first sampling circuit is used for slave One end of the sampling module collects the first sampling signal.
  • the circuit further includes:
  • the first filtering module is respectively connected to one end of the sampling module and the first isolation module;
  • the first isolation module is connected to the first sampling circuit, and the first isolation module is used to isolate the interference of the first sampling circuit on the first sampling signal.
  • the first isolation module includes:
  • a first voltage follower the first input terminal of the first voltage follower is connected to the first filter module, and the output terminal of the first voltage follower is respectively connected to the second input of the first voltage follower The terminal is connected to the first sampling circuit.
  • the circuit further includes:
  • a second sampling circuit the first end of the second sampling circuit is connected to one end of the signal generating module, the second end of the second sampling circuit is connected to the processing module, and the second sampling circuit is used for Collect the second sampling signal from one end of the signal generation module.
  • the circuit further includes:
  • the second filtering module is respectively connected to one end of the signal generating module and the second isolation module;
  • the second isolation module is connected to the second sampling circuit, and the second isolation module is used to isolate the interference of the second sampling circuit on the second sampling signal.
  • the second isolation module includes:
  • a second voltage follower the first input terminal of the second voltage follower is connected to the second filter module, and the output terminal of the second voltage follower is respectively connected to the second input of the second voltage follower Terminal and the second sampling circuit.
  • a battery management system including the capacitance calibration circuit provided in the embodiments of the present application.
  • a capacitance calibration method for use in the capacitance calibration circuit provided in the embodiments of the present application includes:
  • the calibrated capacitance value of the capacitor module is obtained.
  • the calibration of the capacitance module is obtained according to the first sampling signal collected from one end of the sampling module, the second sampling signal collected from one end of the signal generating module, and the predetermined frequency Capacitance value, including:
  • the calibration capacitance value of the capacitance module is obtained.
  • the circuit further includes a resistance module connected to the second switch module; wherein,
  • the obtaining the calibration capacitance value of the capacitance module according to the phase shift, the resistance value of the sampling module and the predetermined frequency includes:
  • the calibration capacitance value of the capacitance module is calculated according to the phase shift, the resistance value of the sampling module, the resistance value of the resistance module, and the predetermined frequency.
  • the calibration of the capacitor module is realized through the first sampling signal, the second sampling signal and the predetermined frequency, which overcomes the problems due to materials, processes, The problem of capacitance deviation of the capacitor module caused by different factors such as environment.
  • FIG. 1 is a schematic structural diagram of a capacitance calibration circuit provided by the first embodiment of the application
  • FIG. 2 is a schematic structural diagram of an insulation detection circuit provided by an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of a capacitance calibration circuit provided by a second embodiment of this application.
  • FIG. 4 is a schematic structural diagram of a capacitance calibration circuit provided by a third embodiment of this application.
  • FIG. 5 is a schematic structural diagram of a capacitance calibration circuit provided by a fourth embodiment of this application.
  • FIG. 6 is a schematic structural diagram of an equivalent circuit corresponding to FIG. 4;
  • FIG. 7 is a schematic structural diagram of an equivalent circuit corresponding to FIG. 5;
  • FIG. 8 is a schematic structural diagram of a capacitance calibration method provided by an embodiment of the application.
  • the power battery in the embodiments of the present 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.
  • the power battery can also be a single battery cell, or a battery module or a battery pack, which is not limited here.
  • FIG. 1 is a schematic structural diagram of a capacitance calibration circuit provided by some embodiments of the application. As shown in Figure 1, the capacitance calibration circuit includes:
  • one end of the first switch module K1 is connected to the positive electrode of the power battery, and the other end of the first switch module K1 is connected to one end of the second switch module K2 and one end of the capacitor module C, respectively.
  • Capacitor module C the other end of capacitor module C is connected to one end of sampling module H.
  • Sampling module H the other end of the sampling module H is connected to one end of the signal generating module S.
  • the signal generating module S the other end of the signal generating module S is connected to the power ground for outputting a signal of a predetermined frequency.
  • the second switch module K2 the other end of the second switch module K2 is connected to the power ground.
  • the processing module P is used to control the first switch module K1 and the second switch module K2, and when the first switch module K1 is in the open state and the second switch module K2 is in the closed state, according to the data collected from one end of the sampling module H
  • the first sampling signal, the second sampling signal collected from one end of the signal generating module S, and the predetermined frequency obtain the calibrated capacitance value of the capacitor module C.
  • Figure 1 also shows the positive capacitance CP, the negative capacitance CN, the positive insulation resistance RP and the negative insulation resistance RN of the power battery.
  • the positive capacitance CP is the equivalent capacitance of the positive electrode of the power battery relative to low-voltage ground
  • the negative capacitance CN is the equivalent capacitance of the negative power battery relative to the low-voltage ground
  • the positive insulation resistance RP is the positive electrode of the power battery relative to the low-voltage ground. (Namely, the power supply ground) insulation resistance
  • the negative insulation resistance RN is the insulation resistance of the negative pole of the power battery relative to the low-voltage ground.
  • the processing module P can collect the voltage signal between the sampling module H and the capacitor module C from one end of the sampling module H, that is, the above-mentioned first sampling signal.
  • the processing module P can collect the voltage signal injected by the signal generating module S from one end of the signal generating module S, that is, the above-mentioned second sampling signal.
  • the processing module P is further configured to control the first switch module K1 to be in the closed state and control the second switch module K2 to be in the off state after obtaining the calibrated capacitance value of the capacitor module C, and according to the capacitance module
  • the calibration capacitance value of C, the third sampling signal collected from one end of the sampling module H, and the fourth sampling signal collected from one end of the signal generating module S are used to calculate the insulation resistance value.
  • FIG. 2 is a detection circuit of the insulation resistance value when the first switch module K1 is in the closed state and the second switch module K2 is in the open state.
  • the effective insulation resistance value Rnp is smaller than RN and RP.
  • the insulation resistance value Rnp can be used as a standard to measure the insulation performance.
  • the sampling module H includes a sampling resistor R1, and the sampling resistor R1 is connected to the capacitor module C and the signal generating module S respectively.
  • ⁇ 1 is the phase shift of the third sampling signal between capacitor module C and sampling resistor R1 relative to the fourth sampling signal output by signal generation module S, based on the basis Erhoff’s law can be expressed as follows:
  • U is the amplitude of the voltage signal generated by the signal generation module S
  • u 1 is the amplitude of the voltage signal between the capacitor module C and the sampling resistor R1
  • the voltage signal generated by the signal generation module S and the capacitor module C and the sampling resistor The voltage signal between R1 is a signal of the same frequency.
  • the phase shift ⁇ 1 can be obtained by using a known phase shift calculation method between signals of the same frequency, which will not be repeated here.
  • C 0 is the calibration capacitance value of capacitance module C.
  • the insulation resistance value Rnp can be obtained.
  • the embodiments of the application effectively improve the accuracy of insulation detection, reduce after-sales costs, improve product reliability, and ensure the safety of vehicles and passengers.
  • the capacitor module C can isolate the high-voltage and low-voltage sampling signals on the power battery side, avoiding the interference of high-voltage to low-voltage, and improving the stability of insulation detection.
  • the signal generation module S may be a direct digital synthesis (DDS) waveform generator.
  • DDS direct digital synthesis
  • the frequency stability and accuracy of the signal sent by the DDS waveform generator can reach the same level as the reference frequency, and fine frequency adjustment can be performed in a wide frequency range.
  • the signal source designed by this method can work in the modulation state, can adjust the output level, and can also output various waveforms, such as sine wave, triangle wave and square wave.
  • FIG. 3 shows a schematic structural diagram of a capacitance calibration circuit provided according to other embodiments of the present application.
  • Figure 3 shows the component composition of some modules in Figure 1.
  • the first switch module K1 includes a switch S1
  • the second switch module K2 includes a switch S2.
  • the capacitor module C includes an isolation capacitor C1
  • the sampling module H includes a sampling resistor R1.
  • the capacitor module C may be a combination of multiple capacitors, and the embodiment of the present application does not specifically limit the connection manner of the multiple capacitors.
  • one end of the switch S1 is connected to the positive electrode of the power battery, and the other end of the switch S1 is respectively connected to one end of the isolation capacitor C1 and one end of the switch S2.
  • the other end of the switch S2 is connected to the power ground.
  • the signal generation module S includes a DDS waveform generator.
  • the other end of the isolation capacitor C1 is connected to one end of the sampling resistor R1, and the other end of the sampling resistor R1 is connected to the DDS waveform generator.
  • the DDS waveform generator is connected to the power ground.
  • the processing module P can directly collect the first sampling signal and the third sampling signal between the sampling resistor R1 and the isolation capacitor C1, and directly collect the second sampling signal from the signal generation module S and the sampling resistor R1.
  • the sampling signal and the fourth sampling signal can also be collected by a dedicated sampling circuit.
  • the capacitance calibration circuit further includes a first sampling circuit D1 and a second sampling circuit D2.
  • the first end of the first sampling circuit D1 is connected to one end of the sampling resistor R1, and the second end of the first sampling circuit D1 is connected to the processing module P.
  • the first sampling circuit D1 is used to collect the voltage signal between the sampling resistor R1 and the isolation capacitor C1 from one end of the sampling resistor R1, such as the first sampling signal or the third sampling signal.
  • the first end of the second sampling circuit D2 is connected to one end of the signal generating module S, the second end of the second sampling circuit D2 is connected to the processing module P, and the second sampling circuit D2 is used to collect DDS signals from one end of the signal generating module S
  • the voltage signal generated by the generator such as the second sampling signal or the fourth sampling signal.
  • the processing module P may be a Microcontroller Unit (MCU), which is used to receive the first sampling signal from the first sampling circuit, and the second sampling signal from the second sampling circuit, and according to the first sampling signal and the second sampling circuit.
  • MCU Microcontroller Unit
  • the sampling signal and the predetermined frequency calculate the capacitance value of the capacitance module C.
  • the processing module may also receive a third sampling signal from the first sampling circuit and a fourth sampling signal from the second sampling circuit, and calculate the insulation based on the second sampling signal, the fourth sampling signal, the capacitance calibration value of the capacitance module C, and a predetermined frequency. resistance.
  • the capacitance calibration circuit further includes: a first filter module B1, a first isolation module G1, a second filter module B2, and a second isolation module G2.
  • the first filter module B1 is respectively connected to one end of the sampling module H and the first isolation module G1.
  • the first isolation module G1 is connected to the first sampling circuit D1.
  • the first isolation module G1 is used to isolate the interference of the first sampling circuit D1 on the signal between the capacitor module C and the sampling module H.
  • the first filter module B1 filters the signal between the capacitor module C and the sampling module H, which can suppress noise and prevent interference, improve the sampling accuracy of the signal between the capacitor module C and the sampling module H, and thereby improve the insulation. Detection accuracy of resistance value.
  • the second filter module B2 is respectively connected to one end of the signal generating module S and the second isolation module G2.
  • the second isolation module G2 is connected to the second sampling circuit D2, and the second isolation module G2 is used to isolate the interference of the second sampling circuit D2 on the signal sent by the DDS waveform generator.
  • the second filter module B2 filters the signal sent by the DDS waveform generator, can suppress noise and prevent interference, improve the sampling accuracy of the signal sent by the DDS waveform generator, and thereby improve the detection accuracy of the insulation resistance value.
  • FIG. 4 shows a schematic structural diagram of a capacitance calibration circuit in some other embodiments of the present application. The difference from FIG. 3 is that FIG. 4 shows the specific structures of the first filter module B1, the first isolation module G1, the second filter module B2, and the second isolation module G2.
  • the first filter module B1 includes a resistor R2 and a capacitor C2.
  • the first isolation module G1 includes a first voltage follower A1.
  • one end of the resistor R2 is connected to one end of the sampling resistor R1, and the other end of the resistor R2 is respectively connected to one end of the capacitor C2 and the first input end of the first voltage follower A1.
  • the other end of the capacitor C2 is connected to the power ground.
  • the second input terminal of the first voltage follower A1 is connected to the output terminal of the first voltage follower A1, and the output terminal of the first voltage follower A1 is connected to the first sampling circuit D1.
  • the second filter module B2 includes a resistor R3 and a capacitor C3.
  • the second isolation module G2 includes a second voltage follower A2.
  • one end of the resistor R3 is connected to the DDS waveform generator, and the other end of the resistor R3 is respectively connected to one end of the capacitor C3 and the first input end of the second voltage follower A2.
  • the other end of the capacitor C3 is connected to the power ground.
  • the second input terminal of the second voltage follower A2 is connected to the output terminal of the second voltage follower A2, and the output terminal of the second voltage follower A2 is connected to the second sampling circuit D2.
  • both the first sampling circuit D1 and the second sampling circuit D2 may include a resistor divider and an MCU. Because the sine wave voltage output by the DDS waveform generator is relatively high, it exceeds the sampling range of the MCU in the first sampling circuit and the MCU in the second sampling circuit. Therefore, it is necessary to divide the voltage signal between the sampling resistor R1 and the isolation capacitor C1 through a resistor divider before sampling. Since the insulation resistance value is generally relatively large, the direct use of resistor divider will cause shunting, making the sampling of the voltage signal between the sampling resistor R1 and the isolation capacitor C1 inaccurate, so adding a voltage follower can increase the input impedance and prevent the first sampling The influence of circuit D1 on the sampled signal. In addition, the voltage follower can also play a role in further filtering.
  • the function of the second voltage follower A2 is similar to that of the first voltage follower A1, and will not be repeated here.
  • the capacitance calibration circuit in order to prevent the safety of the entire vehicle when the first switch module K1 fails, the capacitance calibration circuit further includes a resistance module connected to the second switch module K2.
  • the resistance module can be used to limit the current and ensure the safety of the capacitance calibration circuit and the vehicle.
  • the resistance module includes a resistance R4, one end of the resistance R4 is connected to the other end of the first switch module K1, and the other end of the resistance R4 is connected to the second switch module K2.
  • the resistance module includes a resistance R5, and the resistance R5 is disposed between the second switch module K2 and the power ground.
  • the resistance module may include both resistance R4 and resistance R5.
  • the resistance module can be connected to the second switch module K2.
  • the embodiment of the present application does not make specific restrictions.
  • the capacitance calibration method provided in the embodiments of this application can be used to calibrate the isolation capacitor of the low-frequency AC injection method at the factory, and can also be used for after-sales or the calibration of the isolation capacitor during maintenance in 4S shops. This method can eliminate Environmental factors cause the capacitance value of the capacitor to shift, thereby improving the accuracy of the insulation resistance value detection sample.
  • An embodiment of the present application also provides a battery management system, which includes the above insulation detection circuit.
  • the first switch module K1 when the first switch module K1 is in the open state and the second switch state is in the closed state, it can be based on the first sampling signal between the sampling module H and the capacitor module C and The second sampling signal sent by the signal generating module S obtains the calibrated capacitance value of the capacitor module C.
  • the calculation process for calibrating the capacitance value of the capacitor module C based on the foregoing capacitance calibration circuit in an embodiment of the present application will be described in detail below.
  • FIG. 4 can be equivalent to FIG. 6.
  • the processing module P collects the first sampling signal between the isolation capacitor C1 and the sampling resistor R1, and the second sampling signal with a predetermined frequency output by the signal generation module S.
  • the low-frequency AC signal injected into the circuit by the signal generation module S has the same amplitude as the signal injected by the (insulation detection circuit) in Figure 2, that is, the second sample with a predetermined frequency output by the signal generation module S
  • the voltage amplitude of the signal is U, and the angular frequency w of the injected signal is also the same.
  • the voltage amplitude of the voltage signal between the isolation capacitor C1 and the sampling resistor R1 is u 2 .
  • ⁇ 2 is the phase shift of the first sampling signal relative to the second sampling signal.
  • the phase shift ⁇ 2 can be obtained by using a known phase shift calculation method between signals with the same frequency, which will not be repeated here.
  • FIG. 5 can be equivalent to FIG. 7.
  • the capacitance calibration method in Figure 7 is similar to the calibration method in Figure 6, only the phase shift of the first sampling signal relative to the second sampling signal, the angular frequency w of the injected signal, the sampling resistance R1, the resistance R4, and the resistance
  • the value of R5 can calibrate the capacitance value of the isolation capacitor C1.
  • the processing module P can calibrate the capacitance value of the capacitor module C according to the phase shift of the first sampling signal relative to the second sampling signal, the angular frequency of the injected signal, the resistance value of the sampling module H, and the resistance value of the resistance module. .
  • the capacitance calibration circuit shown in FIG. 6 can be used for factory calibration, and the capacitance calibration circuit in FIG. 7 can be used for calibration of vehicles in after-sales maintenance. After the capacitance value of the capacitance module C is calibrated, the calibrated capacitance value can be used to calculate the insulation resistance value of the entire vehicle.
  • the capacitance calibration circuit provided by the embodiment of the present application can also be used to calibrate the capacitance value of the capacitor in different working environments, so as to improve the accuracy of the insulation resistance of the entire vehicle.
  • FIG. 8 is a schematic flow chart of a capacitance calibration method provided by some embodiments of the application, which is used in the capacitance calibration circuit shown in FIGS. 1 to 7.
  • the capacitance calibration method provided by the embodiment of the application includes the following steps:
  • S810 Control the first switch module K1 to be in the open state and the second switch module K2 to be in the closed state.
  • the capacitance calibration method provided by the embodiments of the present application can calibrate the capacitance module C by using the first sampling signal, the second sampling signal and the predetermined frequency, which is simple and convenient, and improves the accuracy of insulation detection.
  • step S820 includes the following steps:
  • S8202 Obtain a calibration capacitance value of the capacitance module according to the phase shift, the resistance value of the sampling module, and the predetermined frequency.
  • the capacitance calibration circuit further includes a resistance module connected to the second switch module K2, in step S8202, according to the phase shift of the first sampling signal relative to the second sampling signal, the injection signal
  • the capacitance value of the isolation capacitor C1 can be calibrated by the angular frequency w of, the sampling resistor R1, and the resistance values of the resistors R4 and R5 in the resistance module.
  • the embodiment of this application uses a sampling resistor to calibrate the isolation capacitor. Due to the material characteristics, the accuracy of the resistance can reach one-thousandth, and the accuracy can reach one-hundredth in the entire life cycle, so it can be used A higher-precision device can be used to calibrate a relatively lower-precision device.
  • the capacitance value of the isolation capacitor is calibrated through the sampling resistor, the phase shift of the first sampling signal relative to the second sampling signal, and the angular frequency of the injected signal, so as to improve the accuracy of the insulation resistance.

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Abstract

一种电容校准电路、电容校准方法和电池管理系统。该电路包括:第一开关模块(S1),第一开关模块(S1)的一端与动力电池的正极连接,第一开关模块(S1)的另一端分别与第二开关模块(S2)的一端和电容模块(C1)的一端连接;电容模块(C1),其另一端与采样模块(H)的一端连接;采样模块(H),其另一端与信号发生模块(S)的一端连接;信号发生模块(S),其另一端与电源地连接,用于输出预定频率的信号;第二开关模块(S2),其另一端与电源地连接;处理模块(P),用于在第一开关模块(S1)处于断开状态且第二开关模块(S2)处于闭合状态时,根据从采样模块(H)的一端采集的第一采样信号、从信号发生模块(S)的一端采集的第二采样信号以及预定频率,得到电容模块(C1)的校准电容值。根据本电路实现了校准电容模块(C1)的电容值。

Description

电容校准电路、电容校准方法和电池管理系统
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“电容校准电路、电容校准方法和电池管理系统”的中国专利申请201910156857.5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
本申请涉及新能源领域,特别是涉及一种电容校准电路、电容校准方法和电池管理系统。
背景技术
电动汽车替代燃油汽车已成为汽车业发展的趋势,电池包的续行里程、使用寿命及使用安全等对电动汽车的使用都显得尤为重要。动力电池包作为电动汽车的关键部件之一,其高压电的安全性必须放在动力电池系统的首要考虑对象之一。因此,对电动汽车绝缘性能的检测是必不可少的一部分。
目前检测绝缘电阻的方法有低频注入法。低频注入法需要在高压侧与低压侧之间跨接电容模块,电容模块与注入信号之间需要连接采样模块,通过注入信号、电容模块和采样模块之间的信号以及电容模块的电容值等参数来计算整车的绝缘阻值。
由于材料和工艺等因素的影响,电容模块的电容值出厂误差较大,并且随着电容模块使用寿命的增长、温度影响等环境因素,导致电容值的误差变得更大。由于在计算绝缘电阻值的过程中需要利用电容模块的电容值,电容值的误差会使得绝缘阻值的计算值误差偏大,导致绝缘报警误报或警报不及时,从而引起因绝缘带来的危险,因此,对电容进行校准是需要解决的问题。
发明内容
本申请实施例一种电容校准电路、电容校准方法和电池管理系统,实现了对电容模块电容值的校准。
根据本申请实施例的一方面,提供一种电容校准电路,电路包括:
第一开关模块,第一开关模块的一端与动力电池的正极连接,第一开关模块的另一端分别与第二开关模块的一端和电容模块的一端连接;
电容模块,电容模块的另一端与采样模块的一端连接;
采样模块,采样模块的另一端与信号发生模块的一端连接;
信号发生模块,信号发生模块的另一端与电源地连接,用于输出预定频率的信号;
第二开关模块,第二开关模块的另一端与电源地连接;
处理模块,用于控制第一开关模块和第二开关模块,并在第一开关模块处于断开状态且第二开关模块处于闭合状态时,根据从采样模块的一端采集的第一采样信号、从信号发生模块的一端采集的第二采样信号以及预定频率,得到电容模块的校准电容值。
在一个实施例中,所述采样模块包括第一电阻,分别与所述电容模块和所述信号发生模块连接。
在一个实施例中,所述处理模块具体用于根据所述第一采样信号相对于所述第二采样信号的相移、所述采样模块的电阻值和所述预定频率,计算所述电容模块的校准电容值。
在一个实施例中,所述电路还包括与所述第二开关模块连接的电阻模块。
在一个实施例中,所述处理模块,具体用于根据所述第一采样信号相对于所述第二采样信号的相移、所述采样模块的电阻值、所述电阻模块的电阻值和所述预定频率,计算所述电容模块的校准电容值。
在一个实施例中,所述电阻模块包括:
第二电阻,所述第二电阻的一端与所述第一开关模块的另一端连接,所述第二电阻的另一端与所述第二开关模块连接;
和/或,
第三电阻,设置于所述第二开关模块和所述电源地之间。
在一个实施例中,所述电路还包括:
第一采样电路,所述第一采样电路的第一端与所述采样模块的一端连接,所述第一采样电路的第二端与所述处理模块连接,所述第一采样电路用于从所述采样模块的一端采集所述第一采样信号。
在一个实施例中,所述电路还包括:
第一滤波模块,分别与所述采样模块的一端和第一隔离模块连接;
所述第一隔离模块,与所述第一采样电路连接,所述第一隔离模块用于隔离所述第一采样电路对所述第一采样信号的干扰。
在一个实施例中,所述第一隔离模块包括:
第一电压跟随器,所述第一电压跟随器的第一输入端与所述第一滤波模块连接,所述第一电压跟随器的输出端分别与所述第一电压跟随器的第二输入端和所述第一采样电路连接。
在一个实施例中,所述电路还包括:
第二采样电路,所述第二采样电路的第一端与所述信号发生模块的一端连接,所述第二采样电路的第二端与所述处理模块连接,所述第二采样电路用于从所述信号发生模块的一端采集所述第二采样信号。
在一个实施例中,所述电路还包括:
第二滤波模块,分别与所述信号发生模块的一端和第二隔离模块连接;
所述第二隔离模块,与所述第二采样电路连接,所述第二隔离模块用于隔离所述第二采样电路对所述第二采样信号的干扰。
在一个实施例中,所述第二隔离模块包括:
第二电压跟随器,所述第二电压跟随器的第一输入端与所述第二滤波模块连接,所述第二电压跟随器的输出端分别与所述第二电压跟随器的第二输入端和所述第二采样电路连接。根据本申请实施例的另一方面,提供一种电池管理系统,包括如本申请实施例提供的电容校准电路。
根据本申请实施例的再一方面,提供一种电容校准方法,用于如本申请实施例提供的电容校准电路,方法包括:
控制第一开关模块处于断开状态且第二开关模块处于闭合状态;
根据从采样模块的一端采集的第一采样信号、从信号发生模块的一端采集的第二采样信号以及预定频率,得到电容模块的校准电容值。
在一个实施例中,所述根据从所述采样模块的一端采集的第一采样信号、从所述信号发生模块的一端采集的第二采样信号以及所述预定频率,得到所述电容模块的校准电容值,包括:
获取所述第一采样信号相对于所述第二采样信号的相移;
根据所述相移、所述采样模块的电阻值和所述预定频率,得到所述电容模块的校准电容值。
所述电路还包括与所述第二开关模块连接的电阻模块;其中,
所述根据所述相移、所述采样模块的电阻值和所述预定频率,得到所述电容模块的校准电容值,包括:
根据所述相移、所述采样模块的电阻值、所述电阻模块的电阻值和所述预定频率,计算所述电容模块的校准电容值。
根据本申请实施例,在第一开关模块处于断开状态且第二开关处于闭合状态时,通过第一采样信号、第二采样信号和预定频率实现对电容模块的校准,克服由于材料、工艺、环境等不同因素带来的电容模块的容值偏移的问题。
附图说明
下面将通过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。
图1为本申请第一实施例提供的电容校准电路的结构示意图;
图2为本申请实施例提供的绝缘检测电路的结构示意图;
图3为本申请第二实施例提供的电容校准电路的结构示意图;
图4为本申请第三实施例提供的电容校准电路的结构示意图;
图5为本申请第四实施例提供的电容校准电路的结构示意图;
图6为与图4对应的等效电路的结构示意图;
图7为与图5对应的等效电路的结构示意图;
图8为本申请实施例提供的电容校准方法的结构示意图。
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理,但不能用来限制本申请的范围,即本申请不限于所描述的实施例。
需要说明的是,在本文中,诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来,而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且,术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含,从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素,而且还包括没有明确列出的其他要素,或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下,由语句“包括……”限定的要素,并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。
需要说明的是,本申请实施例中的动力电池可以为锂离子电池、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,动力电池也可以为电芯单体,也可以是电池模组或电池包,在此不做限定。
下面首先结合附图对本申请实施例提供的电容校准电路进行详细说明。
图1为本申请一些实施例提供的电容校准电路的结构示意图。如图1所示,电容校准电路包括:
第一开关模块K1,第一开关模块K1的一端与动力电池的正极连接,第一开关模块K1的另一端分别与第二开关模块K2的一端和电容模块C的一端连接。
电容模块C,电容模块C的另一端与采样模块H的一端连接。
采样模块H,采样模块H的另一端与信号发生模块S的一端连接。
信号发生模块S,信号发生模块S的另一端与电源地连接,用于输出预定频率的信号。
第二开关模块K2,第二开关模块K2的另一端与电源地连接。
处理模块P,用于控制第一开关模块K1和第二开关模块K2,并在第一开关模块K1处于断开状态且第二开关模块K2处于闭合状态时,根据从采样模块H的一端采集的第一采样信号、从信号发生模块S的一端采集的第二采样信号以及预定频率,得到电容模块C的校准电容值。
图1中还示出了动力电池的正极电容CP、负极电容CN、正极绝缘电阻RP和负极绝缘电阻RN。
可以理解地是,正极电容CP为动力电池的正极相对于低压地的等效电容,负极电容CN为动力电池负极相对于低压地的等效电容,正极绝缘电阻RP为动力电池正极相对于低压地(即电源地)的绝缘电阻,负极绝缘电阻RN为动力电池负极相对于低压地的绝缘电阻。
本申请的实施例中,处理模块P从采样模块H的一端可以采集到采样模块H和电容模块C之间的电压信号,即上述第一采样信号。处理模块P从信号发生模块S的一端能够采集到信号发生模块S注入的电压信号,即上述第二采样信号。在第一开关模块K1处于断开状态且第二开关模块K2处于闭合状态时,通过第一采样信号、第二采样信号和预定频率实现对电容模块C的校准,克服由于材料、工艺、环境等不同因素带来的电容模块C的电容值偏移的问题。
在本申请的实施例中,处理模块P还用于在获取电容模块C的校准电容值后,控制第一开关模块K1处于闭合状态且控制第二开关模块K2处于断开状态,并依据电容模块C的校准电容值、从采样模块H的一端采集的第三采样信号和从信号发生模块S的一端采集的第四采样信号,计算绝缘电阻值。如图2所示,图2为第一开关模块K1处于闭合状态且第二开关模块K2处于断开状态时,绝缘电阻值的检测电路。
假设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=RP//RN,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,在本申请实施例中,可以将绝缘阻值Rnp作为衡量绝缘性能的标准。
假设附图2中,Cnp和Rnp的等效阻抗为Z,基于基尔霍夫定律,以及电阻和电容的并联公式可得出以下表达式:
Figure PCTCN2020077262-appb-000001
其中,w为信号发生模块S输出信号的角频率,j为虚部符号。作为一个示例,参见图3,采样模块H包括采样电阻R1,采样电阻R1分别与电容模块C和信号发生模块S连接。
假设Z1为Cnp、Rnp以及电容模块C的总阻抗,θ 1为电容模块C与采样电阻R1之间的第三采样信号相对于信号发生模块S输出的第四采样信号的相移,则基于基尔霍夫定律可得出如下表达式:
Figure PCTCN2020077262-appb-000002
其中,U为信号发生模块S产生的电压信号的幅值,u 1为电容模块C与采样电阻R1之间的电压信号的幅值,信号发生模块S产生的电压信号和电容模块C与采样电阻R1之间的电压信号是同频率的信号。其中,相移θ 1可利用已知的同频信号之间的相移计算方法进行获取,在此不再赘述。
其中,Z1与Z之间的关系可以利用如下的表达式进行表示:
Figure PCTCN2020077262-appb-000003
其中,C 0为电容模块C的校准电容值。联合公式(1)、公式(2)和公式(3),即可以得出绝缘阻值Rnp。
由于在计算绝缘电阻值时,需要用到电容模块C的容值,因此通过校准电容模块C的电容值,能够降低绝缘电阻值检测的误差,避免绝缘误报警或绝缘未报警等情况带来的危险。本申请实施例通过对电容模块C的电容值进行校准,有效提高绝缘检测的精度,降低售后的成本,提高产品的可靠性以及保障车辆及乘车人的安全等问题。
在该实施例中,电容模块C能够将动力电池侧的高压和低压采样信号隔离开来,避免了高压对低压的干扰,提高了绝缘检测的稳定性。
在一些实施例中,信号发生模块S可以为直接数字频率合成(Direct Digital Synthesis,DDS)波形发生器。DDS波形发生器发出的信号的频率稳定度和准确度能够达到与基准频率相同的水平,并且可以在很宽的频率范围内进行精细的频率调节。采用这种方法设计的信号源可工作于调制状态,可以对输出电平进行调节,也可以输出各种波形,比如,正弦波、三角波和方波等波形。
图3示出根据本申请另一些实施例提供的电容校准电路的结构示意图。图3示出图1中部分模块的元器件组成。
参见图3,在一些示例中,第一开关模块K1包括开关S1,第二开关模块K2包括开关S2。电容模块C包括隔离电容C1,采样模块H包括采样电阻R1。其中,电容模块C可以为多个电容的组合,关于多个电容的连接方式,本申请实施例不做具体限制。
其中,开关S1的一端与动力电池的正极连接,开关S1的另一端分别与隔离电容C1的一端和开关S2的一端连接。开关S2的另一端与电源地连接。
在一些示例中,信号发生模块S包括DDS波形发生器。其中,隔离电容C1的另一端与采样电阻R1的一端连接,采样电阻R1的另一端与DDS波形发生器连接。并且,DDS波形发生器与电源地连接。
在本申请的实施例中,处理模块P可以直接从采样电阻R1和隔离电容C1之间采集第一采样信号和第三采样信号,以及直接从信号发生模块S和采样电阻R1之间采集第二采样信号和第四采样信号,也可以通过专用的采样电路采集。
参见图3,电容校准电路还包括第一采样电路D1和第二采样电路D2。
在一些实施例中,第一采样电路D1的第一端与采样电阻R1的一端连接,第一采样电路D1的第二端与处理模块P连接。第一采样电路D1用于 从采样电阻R1的一端采集采样电阻R1和隔离电容C1之间的电压信号,例如第一采样信号或第三采样信号。
第二采样电路D2的第一端与信号发生模块S的一端连接,第二采样电路D2的第二端与处理模块P连接,第二采样电路D2用于从信号发生模块S的一端采集DDS信号发生器产生的电压信号,例如第二采样信号或第四采样信号。
其中,处理模块P可以为微控制单元(Microcontroller Unit,MCU),用于从第一采样电路接收第一采样信号,从第二采样电路接收第二采样信号,并根据第一采样信号和第二采样信号以及预定频率计算电容模块C的电容值。
处理模块还可以从第一采样电路接收第三采样信号,从第二采样电路接收第四采样信号,并根据第二采样信号、第四采样信号、电容模块C的电容校准值以及预定频率计算绝缘电阻值。
参见图3,在本申请的一些实施例中,电容校准电路还包括:第一滤波模块B1、第一隔离模块G1、第二滤波模块B2和第二隔离模块G2。
其中,第一滤波模块B1分别与采样模块H的一端和第一隔离模块G1连接。第一隔离模块G1,与第一采样电路D1连接。第一隔离模块G1用于隔离第一采样电路D1对电容模块C和采样模块H之间信号的干扰。
其中,第一滤波模块B1对电容模块C和采样模块H之间的信号进行滤波,能够抑制噪声和防止干扰,提高了对电容模块C和采样模块H之间的信号的采样精度,进而提高绝缘电阻值的检测精度。
其中,第二滤波模块B2分别与信号发生模块S的一端和第二隔离模块G2连接。第二隔离模块G2,与第二采样电路D2连接,第二隔离模块G2用于隔离第二采样电路D2对DDS波形发生器发出的信号的干扰。
其中,第二滤波模块B2对DDS波形发生器发出的信号进行滤波,能够抑制噪声和防止干扰,提高了对DDS波形发生器发出的信号的采样精度,进而提高绝缘电阻值的检测精度。
图4示出本申请再一些实施例中电容校准电路的结构示意图。与图3不同的是,图4示出第一滤波模块B1、第一隔离模块G1、第二滤波模块B2和第二隔离模块G2的具体结构。
参见图4,在一些示例中,第一滤波模块B1包括电阻R2和电容C2。第一隔离模块G1包括第一电压跟随器A1。
其中,电阻R2的一端与采样电阻R1的一端连接,电阻R2的另一端分别与电容C2的一端和第一电压跟随器A1的第一输入端连接。电容C2的另一端与电源地连接。
第一电压跟随器A1的第二输入端与第一电压跟随器A1的输出端连接,第一电压跟随器A1的输出端与第一采样电路D1连接。参见图4,在一些示例中,第二滤波模块B2包括电阻R3和电容C3。第二隔离模块G2包括第二电压跟随器A2。
其中,电阻R3的一端与DDS波形发生器连接,电阻R3的另一端分别与电容C3的一端和第二电压跟随器A2的第一输入端连接。电容C3的另一端与电源地连接。
第二电压跟随器A2的第二输入端与第二电压跟随器A2的输出端连接,第二电压跟随器A2的输出端与第二采样电路D2连接。
其中,第一采样电路D1和第二采样电路D2均可以包括电阻分压器和MCU。由于DDS波形发生器输出的正弦波电压比较高,超过了第一采样电路中MCU和第二采样电路中MCU的采样范围。因此需要将采样电阻R1与隔离电容C1之间的电压信号通过电阻分压器分压后再进行采样。由于绝缘电阻值一般比较大,直接采用电阻分压会导致分流,使得对采样电阻R1与隔离电容C1之间的电压信号采样不准,因此加入电压跟随器可以增大输入阻抗,防止第一采样电路D1对采样信号的影响。并且,电压跟随器还可以起到进一步滤波的作用。
第二电压跟随器A2的作用与第一电压跟随器A1类似,在此不再赘述。
在本申请的一些实施例中,为了防止第一开关模块K1失效时提高整车安全性,电容校准电路还包括与第二开关模块K2连接的电阻模块。通 过利用电阻模块可以起到限流作用,保证了电容校准电路和整车的安全性。
参见图5,在一些示例中,电阻模块包括电阻R4,电阻R4的一端与第一开关模块K1的另一端连接,电阻R4的另一端与第二开关模块K2连接。在另一些示例中,电阻模块包括电阻R5,电阻R5设置于第二开关模块K2和电源地之间。在另一些示例中,电阻模块可以既包括电阻R4,也包括电阻R5。
也就是说,电阻模块与第二开关模块K2连接即可,至于电阻模块的具体结构和具体位置,本申请实施例不做具体限制。
本申请实施例提供的电容校准方法,既可应用于出厂对低频交流注入法的隔离电容做校准,也可用于售后,或者4S店进行保养时对隔离电容进行校准,通过此种方法可以消除因为环境因素导致的电容的容值偏移,从而提高绝缘阻值的检测样精度。
本申请实施例还提供一种电池管理系统,该电池管理系统包括如上的绝缘检测电路。
在本申请实施例中,基于上述电容校准电路,当第一开关模块K1处于断开状态且第二开关状态处于闭合状态时,可以根据采样模块H和电容模块C之间的第一采样信号以及信号发生模块S发出的第二采样信号,得到电容模块C的校准电容值。下面对本申请实施例的基于上述电容校准电路对电容模块C的电容值进行校准的计算过程进行详细说明。
请参照图6所示出的电容校准电路,当第一开关模块K1处于断开状态且第二开关状态处于闭合状态时,可以将图4等效为图6。
处理模块P采集隔离电容C1和采样电阻R1之间的第一采样信号,以及信号发生模块S输出的具有预定频率的第二采样信号。
假设在图6中,信号发生模块S向电路中注入的低频交流信号与附图2中(绝缘检测电路)注入的信号的幅值相同,即信号发生模块S输出的具有预定频率的第二采样信号的电压幅值为U,注入信号的角频率w也相同。假设隔离电容C1和采样电阻R1之间的电压信号的电压幅值为u 2
根据基尔霍夫定律,可得出以下表达式:
Figure PCTCN2020077262-appb-000004
其中,θ 2为第一采样信号相对于第二采样信号的相移。其中,相移θ 2可利用已知的同频信号之间的相移计算方法进行获取,在此不再赘述。
将以上公式(4)化简可以得出以下表达式:
U=u 2×(cosθ 2-C1×R1×w×sinθ 2+C1×R1×w×cosθ 2×j+sinθ 2×j)  (5)
由虚部等于0得以下表达式:
sinθ 2×j+C1×R1×w×cosθ 2×j=0      (6)
因此可以得出隔离电容C1的表达式:
Figure PCTCN2020077262-appb-000005
因此只需要得到第一采样信号相对于第二采样信号的相移θ2、注入信号的角频率w以及采样电阻R1的值,即可校准隔离电容C1的容值。
请参照图7所示出的电容校准电路,当第一开关模块K1处于断开状态且第二开关模块K2处于闭合状态时,可以将图5等效为图7。对于图7中电容校准的方法与图6中的校准方法相类似,只需要得到第一采样信号相对于第二采样信号的相移、注入信号的角频率w、采样电阻R1、电阻R4和电阻R5的值,即可校准隔离电容C1的容值。
也就是说,处理模块P根据第一采样信号相对于第二采样信号的相移、注入信号的角频率、采样模块H的电阻值和电阻模块的电阻值,即可校准电容模块C的容值。
对于图6所示的电容校准电路可以用于出厂校准,图7中的电容校准电路可用于车辆在售后维护中进行校准。当对电容模块C的电容值进行校准之后,则可以利用校准的电容值计算整车的绝缘电阻值。本申请实施例提供的电容校准电路也可用于在不同工作环境中对电容的容值进行校准,以提高整车绝缘阻值的精度。
图8为本申请一些实施例提供的电容校准方法的流程示意图,用于如图1-图7的电容校准电路。本申请实施例提供的电容校准方法包括以下步骤:
S810,控制第一开关模块K1处于断开状态且第二开关模块K2处于闭合状态。
S820,根据从采样模块H的一端采集的第一采样信号、从信号发生模块S的一端采集的第二采样信号以及预定频率,得到电容模块C的校准电容值。
本申请实施例提供的电容校准方法,通过利用第一采样信号、第二采样信号和预定频率即可以对电容模块C进行校准,简单方便,提高了绝缘检测的精准度。
在本申请的一些实施例中,参见图6,步骤S820包括以下步骤:
S8201,获取所述第一采样信号相对于所述第二采样信号的相移。
S8202,根据所述相移、所述采样模块的电阻值和所述预定频率,得到所述电容模块的校准电容值。
具体地,可参照上述介绍的基于电容校准电路对隔离电容进行校准的计算过程,在此不再赘述。
相类似地,参见图7,若电容校准电路还包括与所述第二开关模块K2连接的电阻模块,则在步骤S8202中,根据第一采样信号相对于第二采样信号的相移、注入信号的角频率w、采样电阻R1以及电阻模块中电阻R4和电阻R5的电阻值,即可校准隔离电容C1的容值。
在校准过程中,本申请实施例是通过采样电阻去校准隔离电容,由于材料特性,电阻的精度可以达到千分之一,在整个使用寿命周期里可以达到百分之一的精度,因此可以用一个精度更高的器件去校准精度相对较低的器件。通过采样电阻、第一采样信号相对于第二采样信号的相移,注入信号的角频率来校准隔离电容的容值,以提高绝缘阻值的精度。
需要明确的是,本说明书中的各个实施例均采用递进的方式描述,各个实施例之间相同或相似的部分互相参见即可,每个实施例重点说明的都是与其他实施例的不同之处。对于电容校准方法实施例而言,相关之处可 以参见电容校准电路的说明部分。本申请并不局限于上文所描述并在图中示出的特定步骤和结构。本领域的技术人员可以在领会本申请的精神之后,作出各种改变、修改和添加,或者改变步骤之间的顺序。并且,为了简明起见,这里省略对已知方法技术的详细描述。
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 (16)

  1. 一种电容校准电路,其中,所述电路包括:
    第一开关模块,所述第一开关模块的一端与动力电池的正极连接,所述第一开关模块的另一端分别与第二开关模块的一端和电容模块的一端连接;
    所述电容模块,所述电容模块的另一端与采样模块的一端连接;
    所述采样模块,所述采样模块的另一端与信号发生模块的一端连接;
    所述信号发生模块,所述信号发生模块的另一端与电源地连接,用于输出预定频率的信号;
    所述第二开关模块,所述第二开关模块的另一端与所述电源地连接;
    处理模块,用于控制所述第一开关模块和所述第二开关模块,并在所述第一开关模块处于断开状态且所述第二开关模块处于闭合状态时,根据从所述采样模块的一端采集的第一采样信号、从所述信号发生模块的一端采集的第二采样信号以及所述预定频率,得到所述电容模块的校准电容值。
  2. 根据权利要求1所述的电路,其中,所述采样模块包括第一电阻,分别与所述电容模块和所述信号发生模块连接。
  3. 根据权利要求1所述的电路,其中,所述处理模块具体用于根据所述第一采样信号相对于所述第二采样信号的相移、所述采样模块的电阻值和所述预定频率,计算所述电容模块的校准电容值。
  4. 根据权利要求1所述的电路,其中,所述电路还包括与所述第二开关模块连接的电阻模块。
  5. 根据权利要求4所述的电路,其中,所述处理模块,具体用于根据所述第一采样信号相对于所述第二采样信号的相移、所述采样模块的电阻值、所述电阻模块的电阻值和所述预定频率,计算所述电容模块的校准电容值。
  6. 根据权利要求4所述的电路,其中,所述电阻模块包括:
    第二电阻,所述第二电阻的一端与所述第一开关模块的另一端连接,所述第二电阻的另一端与所述第二开关模块连接;
    和/或,
    第三电阻,设置于所述第二开关模块和所述电源地之间。
  7. 根据权利要求1所述的电路,其中,所述电路还包括:
    第一采样电路,所述第一采样电路的第一端与所述采样模块的一端连接,所述第一采样电路的第二端与所述处理模块连接,所述第一采样电路用于从所述采样模块的一端采集所述第一采样信号。
  8. 根据权利要求7所述的电路,其中,所述电路还包括:
    第一滤波模块,分别与所述采样模块的一端和第一隔离模块连接;
    所述第一隔离模块,与所述第一采样电路连接,所述第一隔离模块用于隔离所述第一采样电路对所述第一采样信号的干扰。
  9. 根据权利要求8所述的电路,其中,所述第一隔离模块包括:
    第一电压跟随器,所述第一电压跟随器的第一输入端与所述第一滤波模块连接,所述第一电压跟随器的输出端分别与所述第一电压跟随器的第二输入端和所述第一采样电路连接。
  10. 根据权利要求1所述的电路,其中,所述电路还包括:
    第二采样电路,所述第二采样电路的第一端与所述信号发生模块的一端连接,所述第二采样电路的第二端与所述处理模块连接,所述第二采样电路用于从所述信号发生模块的一端采集所述第二采样信号。
  11. 根据权利要求10所述的电路,其中,所述电路还包括:
    第二滤波模块,分别与所述信号发生模块的一端和第二隔离模块连接;
    所述第二隔离模块,与所述第二采样电路连接,所述第二隔离模块用于隔离所述第二采样电路对所述第二采样信号的干扰。
  12. 根据权利要求11所述的电路,其中,所述第二隔离模块包括:
    第二电压跟随器,所述第二电压跟随器的第一输入端与所述第二滤波模块连接,所述第二电压跟随器的输出端分别与所述第二电压跟随器的第二输入端和所述第二采样电路连接。
  13. 一种电池管理系统,其中,包括如权利要求1-12任意一项所述的电容校准电路。
  14. 一种电容校准方法,用于如权利要求1至12中任意一项所述的电容校准电路,其中,所述方法包括:
    控制所述第一开关模块处于断开状态且所述第二开关模块处于闭合状态;
    根据从所述采样模块的一端采集的第一采样信号、从所述信号发生模块的一端采集的第二采样信号以及所述预定频率,得到所述电容模块的校准电容值。
  15. 根据权利要求14所述的方法,其中,所述根据从所述采样模块的一端采集的第一采样信号、从所述信号发生模块的一端采集的第二采样信号以及所述预定频率,得到所述电容模块的校准电容值,包括:
    获取所述第一采样信号相对于所述第二采样信号的相移;
    根据所述相移、所述采样模块的电阻值和所述预定频率,得到所述电容模块的校准电容值。
  16. 根据权利要求15所述的方法,其中,所述电路还包括与所述第二开关模块连接的电阻模块;其中,
    所述根据所述相移、所述采样模块的电阻值和所述预定频率,得到所述电容模块的校准电容值,包括:
    根据所述相移、所述采样模块的电阻值、所述电阻模块的电阻值和所述预定频率,计算所述电容模块的校准电容值。
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