Alternating current frequency detection circuit and battery management system

Abstract

The utility model provides an alternating current frequency detection circuit and a battery management system, and belongs to the technical field of frequency detection. The alternating current frequency detection circuit comprises an acquisition unit and a frequency detection unit, the acquisition unit comprises a first voltage division module and a second voltage division module, a first end of the first voltage division module is connected with one end of an alternating current power supply, and a second end is connected with a first direct current power supply; the fourth end of the second voltage dividing module is connected with the other end of the AC power supply, and the fifth end is connected with a first DC power supply which is used for enabling the third end and the sixth end to output positive voltage; the first input end of the frequency detection unit is connected with the third end, the second input end is connected with the sixth end, the first output end is used for outputting a level signal corresponding to the AC power supply, and the level signal is used for indicating the frequency corresponding to the AC power supply. According to the invention, the detection of the frequency of the alternating current is realized through a hardware circuit composed of the acquisition unit and the frequency detection unit, and the technical problem that the detection process of detecting the frequency of the alternating current through software is tedious is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of frequency detection, and particularly relates to an alternating current frequency detection circuit and a battery management system. BACKGROUND

[0002] With the vigorous development of electric vehicles in the new energy field and the continuous pursuit of reliability and intelligence of electric vehicles, the battery management system of the electric vehicle is also developing towards integration and intelligence. The high or low of the alternating current charging frequency directly affects the charging efficiency. Stable alternating current frequency can ensure the stability of current and voltage in the charging process, thereby avoiding unnecessary damage to the electric vehicle battery. Therefore, it is particularly necessary to detect the frequency of alternating current in the charging process. However, the traditional frequency detection method, especially the detection relying on algorithms and signal processing technology software, makes the detection process more cumbersome. CONTENT OF THE UTILITY MODEL

[0003] In view of the above problems, the application provides an alternating current frequency detection circuit and a battery management system, which solve the technical problem of cumbersome detection process of alternating current frequency detection by software.

[0004] The application embodiment provides an alternating current frequency detection circuit, which comprises a collection unit, the collection unit comprising a first voltage division module and a second voltage division module, the first voltage division module having a first end, a second end and a third end, the first end being connected to one end of an alternating current power supply, the second end being connected to a first direct current power supply, the second voltage division module having a fourth end, a fifth end and a sixth end, the fourth end being connected to the other end of the alternating current power supply, the fifth end being connected to the first direct current power supply, and the first direct current power supply being used to output a positive voltage from the third end and the sixth end.

[0005] The application embodiment provides an alternating current frequency detection circuit, which comprises a collection unit, the collection unit comprising a first voltage division module and a second voltage division module, the first voltage division module having a first end, a second end and a third end, the first end being connected to one end of an alternating current power supply, the second end being connected to a first direct current power supply, the second voltage division module having a fourth end, a fifth end and a sixth end, the fourth end being connected to the other end of the alternating current power supply, the fifth end being connected to the first direct current power supply, and the first direct current power supply being used to output a positive voltage from the third end and the sixth end.

[0006] In some embodiments, the first voltage division module comprises a first voltage division device and a second voltage division device, one end of the first voltage division device is configured as the first end, one end of the second voltage division device is configured as the second end, the other end of the first voltage division device is connected to the other end of the second voltage division device, and the other end of the first voltage division device and the other end of the second voltage division device are connected to the third end.

[0007] The second voltage division module comprises a third voltage division device and a fourth voltage division device, one end of the third voltage division device is configured as the fourth end, one end of the fourth voltage division device is configured as the fifth end, the other end of the third voltage division device is connected to the other end of the fourth voltage division device, and the other end of the third voltage division device and the other end of the fourth voltage division device are connected to the sixth end.

[0008] The voltage division ratios of the first voltage division module and the second voltage division module are the same.

[0009] In some embodiments, the frequency detection unit comprises a comparison module, the comparison module comprises a comparator, the comparator comprises a non-inverting input end, an inverting input end and a fourth output end, the non-inverting input end is connected to the first input end, the inverting input end is connected to the second input end, and the fourth output end is connected to the first output end.

[0010] In some embodiments, the frequency detection unit further comprises a processing module, the processing module comprises a voltage stabilizing circuit, an amplification circuit and an isolation circuit, the voltage stabilizing circuit and the amplification circuit are both connected to the fourth output end, the isolation circuit is connected to the amplification circuit, and the isolation circuit is further connected to the first output end.

[0011] In some embodiments, the voltage stabilizing circuit comprises a first voltage stabilizing unit and a second voltage stabilizing unit, one end of the first voltage stabilizing unit is connected to the fourth output end, the other end of the first voltage stabilizing unit is connected to the second direct current power supply, one end of the second voltage stabilizing unit is connected to the fourth output end, and the other end of the second voltage stabilizing unit is grounded.

[0012] In some embodiments, the amplification circuit comprises a triode, the base of the triode is connected to the fourth output end, the emitter of the triode is grounded, and the collector of the triode is connected to the isolation circuit.

[0013] In some embodiments, the isolation circuit comprises an optical coupler, the optical coupler comprises a third input end, a fourth input end, a second output end and a third output end, the third input end is connected to the amplification circuit, the fourth input end is connected to the second direct current power supply, the second output end is grounded, and the third output end is configured as the first output end and connected to the third direct current power supply.

[0014] In some embodiments, the processing module further comprises a first protection circuit, the first protection circuit comprises a diode, the positive electrode of the diode is connected to the base of the triode, and the negative electrode of the diode is connected to one end of the second voltage stabilizing unit.

[0015] In some embodiments, the processing module further comprises a second protection unit, the second protection unit comprises a first resistor, one end of the first resistor is connected to the third input end, and the other end of the first resistor is connected to the fourth input end.

[0016] Correspondingly, the application also provides a battery management system comprising the alternating current frequency detection circuit in the above embodiments.

[0017] The application has the beneficial effects that the alternating current frequency detection circuit of the embodiment of the application comprises a collection unit and a frequency detection unit, the collection unit comprises a first voltage division module and a second voltage division module, the first voltage division module has a first end, a second end and a third end, the first end is connected to one end of an alternating current power supply, the second end is connected to a first direct current power supply, the second voltage division module has a fourth end, a fifth end and a sixth end, the fourth end is connected to the other end of the alternating current power supply, the fifth end is connected to the first direct current power supply, and the first direct current power supply is used to output a positive voltage from the third end and the sixth end; the frequency detection unit has a first input end, a second input end and a first output end, the first input end is connected to the third end, the second input end is connected to the sixth end, and the first output end is used to output a level signal corresponding to the alternating current power supply, and the level signal is used to indicate the frequency corresponding to the alternating current power supply. The application realizes the detection of the frequency of the alternating current through the hardware circuit composed of the collection unit and the frequency detection unit, and solves the technical problem that the detection process of the frequency of the alternating current through software detection is complicated. Moreover, the application inputs both ends of the alternating current power supply into the frequency detection unit through the collection unit, so that the output level signal corresponding to the alternating current power supply is more stable.

[0018] The battery management system of the embodiment of the application comprises the alternating current frequency detection circuit in the above embodiment. Therefore, all the technical features and technical effects of the alternating current frequency detection circuit can be had, and details are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0020] Figure 1 The structure block diagram of an alternating current frequency detection circuit of the embodiment of the application is shown in FIG. 1.

[0021] Figure 2 Another structure block diagram of the alternating current frequency detection circuit of the embodiment of the application is shown in FIG. 2.

[0022] Figure 3 Still another structure block diagram of the alternating current frequency detection circuit of the embodiment of the application is shown in FIG. 3.

[0023] Figure 4 Still another structure block diagram of the alternating current frequency detection circuit of the embodiment of the application is shown in FIG. 4.

[0024] Figure 5 A circuit diagram of the alternating current frequency detection circuit of the embodiment of the application is shown in FIG. 5.

[0025] Explanation of reference signs: 10 - acquisition unit, 11 - first voltage division module, 111 - first end, 112 - second end, 113 - third end, 114 - first voltage division device, 115 - second voltage division device, 12 - second voltage division module, 121 - fourth end, 122 - fifth end, 123 - sixth end, 124 - third voltage division device, 125 - fourth voltage division device, 20 - alternating current power supply, 30 - first direct current power supply, 40 - frequency detection unit, 41 - first input end, 42 - second input end, 43 - first output end, 44 - comparison module, 45 - processing module, 451 - voltage stabilizing circuit, 4511 - first voltage stabilizing unit, 4512 - second voltage stabilizing unit, 452 - amplification circuit, 453 - isolation circuit, 454 - first protection circuit, 455 - second protection unit, 50 - second direct current power supply, 60 - third direct current power supply. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0027] In the description of the present application, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. The orientations or positional relationships indicated by the terms "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features.

[0028] The present application provides an alternating current frequency detection circuit and a battery management system, which are described in detail below. It should be noted that the description order of the following embodiments is not used as a limitation on the preferred order of the embodiments of the present application. In the following embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0029] As a preamble of the embodiments of the present application, with the vigorous development of electric vehicles in the new energy field, and people's continuous pursuit of reliability and intelligence of electric vehicles, the battery management system BMS of electric vehicles is also developing towards integration and intelligence, of course, various charging piles and charging guns also emerge. At present, most of the charging guns are AC-DC shared to provide more flexibility and charging options, and then in the charging process, AC-DC detection is needed to identify whether the charging gun input is AC or DC, and through the identification result, the corresponding charging relay is controlled to be closed and opened. In the case of detecting that the charging gun input is AC, in order to ensure the normal operation of the charging system, the compatibility and safety of the equipment, it is necessary to further detect the frequency of AC, and the high and low of the frequency of AC charging directly affects the efficiency of charging, and stable AC frequency can ensure the stability of current and voltage in the charging process, thereby avoiding unnecessary damage to the electric vehicle battery, and then, it is particularly necessary to detect the frequency of AC in the charging process. However, the traditional frequency detection method, especially the detection by relying on algorithm and signal processing technology and the like software, makes the detection process more cumbersome.

[0030] Therefore, the present application provides an AC frequency detection circuit, which realizes the detection of AC frequency through a hardware circuit composed of an acquisition unit and a frequency detection unit. The present application aims to solve at least one of the above technical problems.

[0031] Please refer to Figure 1 , Figure 1 is a structural block diagram of an AC frequency detection circuit according to an embodiment of the present application. The present application provides an AC frequency detection circuit, which comprises: an acquisition unit 10, the acquisition unit 10 comprising a first voltage dividing module 11 and a second voltage dividing module 12, the first voltage dividing module 11 having a first end 111, a second end 112 and a third end 113, the first end 111 being connected to one end of an AC power supply 20, the second end 112 being connected to a first DC power supply 30, the second voltage dividing module 12 having a fourth end 121, a fifth end 122 and a sixth end 123, the fourth end 121 being connected to the other end of the AC power supply 20, the fifth end 122 being connected to the first DC power supply 30, the first DC power supply 30 being used to output a positive voltage from the third end 113 and the sixth end 123; a frequency detection unit 40, the frequency detection unit 40 having a first input end 41, a second input end 42 and a first output end 43, the first input end 41 being connected to the third end 113, the second input end 42 being connected to the sixth end 123, the first output end 43 being used to output a level signal corresponding to the AC power supply 20, the level signal being used to indicate the frequency corresponding to the AC power supply 20.

[0032] It needs to be understood that the alternating power supply 20 can be the mains electricity connected by the charging gun through the charging pile, the voltage value of the first direct current power supply 30 can be designed according to the actual scheme requirement, the second end 112 and the fifth end 122 are connected to the positive pole of the first direct current power supply 30, which is used to lift the voltage output by the voltage dividing module at both ends of the alternating power supply 20, so that the third end 113 and the sixth end 123 output positive voltage, and then the frequency detection unit 40 outputs the level signal corresponding to the alternating power supply 20, in addition, the second end 112 and the fifth end 122 are connected to the positive pole of the first direct current power supply 30, and the second end 112 and the fifth end 122 are also connected; The acquisition unit 10 is used to input the voltage at both ends of the alternating power supply 20 into the corresponding first input end 41 and second input end 42 of the frequency detection unit 40 through the first voltage dividing module 11 and the second voltage dividing module 12 after voltage division; The first voltage dividing module 11 and the second voltage dividing module 12 are used to divide the voltage input from the alternating power supply 20 into smaller output voltage to the corresponding first input end 41 and second input end 42, so as to adapt to the circuit requirement, and reduce the voltage to the safe range, so as to protect the subsequent components from the influence of overvoltage; The level signal can be high level and low level which will change periodically with time, that is, the level signal is a square wave signal, and then the level signal can be used to indicate the frequency corresponding to the alternating power supply 20. In addition, it needs to be explained that G1 in the figure represents a device for detecting the level signal, and in some embodiments, the first output end 43 of the frequency detection unit 40 can be connected with the MCU or other control devices, so as to realize the detection of the frequency of the alternating power supply 20 based on the level signal output by the first output end 43 through the control device.

[0033] Through the above technical scheme, the acquisition unit 10 and the frequency detection unit 40 constitute a hardware circuit to realize the detection of the alternating current frequency, and the hardware circuit can provide more stable output signal, which solves the technical problem that the detection process of the alternating current frequency through software detection is complicated; and by inputting the voltage at both ends of the alternating power supply 20 into the frequency detection unit 40 through the acquisition unit 10, the frequency measurement error caused by inaccurate signal acquisition or other input signal interference can be avoided, so that the level signal corresponding to the output alternating power supply 20 is more stable, and the accuracy and reliability of the frequency detection are improved.

[0034] Please refer to Figure 2 shown, Figure 2Another structural block diagram of the alternating current frequency detection circuit is shown in the embodiments of the present application; in some embodiments, the first voltage division module 11 includes a first voltage division device 114 and a second voltage division device 115, one end of the first voltage division device 114 is configured as the first end 111, one end of the second voltage division device 115 is configured as the second end 112, the other end of the first voltage division device 114 is connected to the other end of the second voltage division device 115, and the other end of the first voltage division device 114 and the other end of the second voltage division device 115 are connected to the third end 113; the second voltage division module 12 includes a third voltage division device 124 and a fourth voltage division device 125, one end of the third voltage division device 124 is configured as the fourth end 121, one end of the fourth voltage division device 125 is configured as the fifth end 122, the other end of the third voltage division device 124 is connected to the other end of the fourth voltage division device 125, and the other end of the third voltage division device 124 and the other end of the fourth voltage division device 125 are connected to the sixth end 123; the voltage division ratio of the first voltage division module 11 and the second voltage division module 12 is the same.

[0035] It should be understood that the voltage division ratio of the first voltage division module 11 refers to the ratio between the voltage output by the third end 113 and the voltage input by the first end 111; the voltage division ratio of the second voltage division module 12 refers to the ratio between the voltage output by the sixth end 123 and the voltage input by the fourth end 121; the voltage division ratio of the first voltage division module 11 and the second voltage division module 12 is the same, so that when the voltage input by the first end 111 and the voltage input by the fourth end 121 changes, the voltage output by the third end 113 and the voltage output by the sixth end 123 also changes in the same proportion, thereby maintaining a stable voltage relationship, and then facilitating the frequency detection unit 40 to output a level signal indicating the frequency corresponding to the alternating current power supply 20. It should be noted that the first voltage division module 11 and the second voltage division module 12 can also include other voltage division devices, which are designed according to actual scheme design requirements.

[0036] For example, please refer to Figure 5 shown, Figure 5This is a circuit diagram of an AC frequency detection circuit according to an embodiment of the present application. The first voltage divider 114, the second voltage divider 115, the third voltage divider 124, and the fourth voltage divider 125 can all be resistors. The first voltage divider 114 is a resistor R1, the second voltage divider 115 is a resistor R4, the third voltage divider 124 is a resistor R2, and the fourth voltage divider 125 is R3. One end of the resistor R1 is configured as a first end 111 connected to one end of the AC power source 20, one end of the resistor R4 is configured as a second end 112 connected to the positive electrode of the first DC power source 30, the other end of the resistor R1 is connected to the other end of the resistor R4, and the other end of the resistor R1 and the other end of the resistor R4 are connected to the third end 113, that is, after the other end of the resistor R1 and the other end of the resistor R4 are connected, the other end of the resistor R1 and the other end of the resistor R4 are connected. There is a connection point between the other end to connect to the third end 113; one end of the resistor R2 is configured as the fourth end 121 connected to the other end of the AC power supply 20, and one end of the resistor R3 is configured as the fifth end 122 connected to the positive electrode of the first DC power supply 30. The other end of the resistor R2 is connected to the other end of the resistor R3, and the other end of the resistor R2 and the other end of the resistor R3 are connected to the sixth end 123, that is, after the other end of the resistor R2 and the other end of the resistor R3 are connected, there is a connection point between the other end of the resistor R2 and the other end of the resistor R3 to connect to the sixth end 123. It should be noted that after one end of the resistor R3 is connected to one end of the resistor R4, there is a connection point between one end of the resistor R3 and one end of the resistor R4 to connect to the positive electrode of the first DC power supply 30.

[0037] Through the above technical solution, the first voltage divider module 11 and the second voltage divider module 12 each include multiple voltage divider components. By connecting the multiple voltage divider components together, the parameters of the multiple voltage divider components can be adjusted as needed, achieving more flexible and precise voltage division to achieve the desired output voltage. In addition, the first voltage divider module 11 and the second voltage divider module 12 have the same voltage divider ratio, so that the voltage output by the third terminal 113 and the voltage output by the sixth terminal 123 maintain a stable voltage relationship, thereby facilitating the frequency detection unit 40 to output a level signal indicating the frequency corresponding to the AC power source 20, thereby ensuring a more accurate frequency corresponding to the AC power source 20.

[0038] See also Figure 3 and Figure 5 As shown, Figure 3 This is another structural block diagram of the AC frequency detection circuit according to an embodiment of the present application. Figure 5 This is a circuit diagram of an AC frequency detection circuit according to an embodiment of the present application. In some embodiments, the frequency detection unit 40 includes a comparison module 44, which includes a comparator. The comparator includes a non-inverting input terminal, an inverting input terminal, and a fourth output terminal. The non-inverting input terminal is connected to the first input terminal 41, the inverting input terminal is connected to the second input terminal 42, and the fourth output terminal is connected to the first output terminal 43.

[0039] It needs to be understood that the comparison module 44 is used to compare the size of the two input voltage signals of the first input end 41 and the second input end 42, and generate a corresponding output signal, and then the signal output by the comparison module 44 is a high level and a low level which will periodically change over time, that is, the signal output by the comparison module 44 is a corresponding square wave signal which can be used to indicate the corresponding frequency of the alternating power supply 20.

[0040] For example, the comparison module 44 includes a comparator U1, the non-inverting input end of the comparator U1 is connected to the first input end 41, the inverting input end is connected to the second input end 42, and the fourth output end is connected to the first output end 43, wherein the fourth output end is the output end of the comparator U1; in addition, the comparison module 44 also includes resistors R5 and R6, one end of the resistor R5 is configured as the first input end 41, the other end of the resistor R5 is connected to the non-inverting input end, one end of the resistor R6 is configured as the second input end 42, and the other end of the resistor R6 is connected to the inverting input end; and the comparator U1 also includes a power supply end and a ground end, the power supply end is used to connect the positive electrode of the second direct current power supply 50, and the ground end is used to ground; wherein the resistors R5 and R6 are used to provide voltage division and current limiting of the input signals of the first input end 41 and the second input end 42, so as to ensure the accuracy and stability of the comparator.

[0041] Through the above technical solution, the frequency detection unit 40 can output a square wave signal through the comparison module 44 including a comparator, that is, a level signal used to indicate the corresponding frequency of the alternating power supply 20, and then the corresponding frequency of the alternating power supply 20 can be obtained; it needs to be noted that the voltage signal waveform of the alternating power supply 20 is a sine waveform, and based on the fact that the waveforms on both ends of the alternating power supply 20 are opposite, the two ends of the alternating power supply 20 are respectively connected to the comparison module 44 through the acquisition unit 10, and the comparison module 44 outputs a corresponding square wave signal based on the comparator; in this application, on the one hand, connecting the two ends of the alternating power supply 20 to the comparison module 44 through the acquisition unit 10 can avoid introducing interference by using other reference signals, thereby improving the stability of the output of the comparison module 44, and then ensuring the accuracy and reliability of the square wave signal, and then realizing the accurate detection of the frequency of the alternating power supply 20, on the other hand, the output square wave signal facilitates obtaining the frequency information of the alternating power supply 20, and then facilitates the detection of the frequency.

[0042] Please refer to Figure 4 as shown, Figure 4Another structural diagram of the AC frequency detection circuit is shown in FIG. 6. In some embodiments, the frequency detection unit 40 further comprises a processing module 45, which comprises a voltage stabilizing circuit 451, an amplifying circuit 452, and an isolation circuit 453. The voltage stabilizing circuit 451 and the amplifying circuit 452 are both connected to the fourth output terminal, and the isolation circuit 453 is connected to the amplifying circuit 452 and the first output terminal 43.

[0043] It should be understood that the processing module 45 is used to process the signal output by the comparison module 44, so as to detect the frequency and ensure the stability and reliability of the signal; the voltage stabilizing circuit 451 is used to stabilize the voltage of the input signal at a fixed level, so as to facilitate subsequent processing and analysis; the amplifying circuit 452 is used to amplify the amplitude of the signal, so as to facilitate driving the isolation circuit 453; and the isolation circuit 453 is used to isolate the electrical connection between the frequency detection unit 40 and the subsequent circuit, so as to prevent interference and protect the safety of the subsequent circuit.

[0044] Further, please refer to Figure 4 , and Figure 4 Another structural diagram of the AC frequency detection circuit is shown in FIG. 6. In some embodiments, the voltage stabilizing circuit 451 comprises a first voltage stabilizing unit 4511 and a second voltage stabilizing unit 4512. One end of the first voltage stabilizing unit 4511 is connected to the fourth output terminal, and the other end of the first voltage stabilizing unit 4511 is connected to the second DC power supply 50. One end of the second voltage stabilizing unit 4512 is connected to the fourth output terminal, and the other end of the second voltage stabilizing unit 4512 is grounded.

[0045] It should be understood that the first voltage stabilizing unit 4511 and the second voltage stabilizing unit 4512 are used to ensure that the output terminal of the comparison module 44 maintains a stable output state. The presence of the first voltage stabilizing unit 4511 and the second voltage stabilizing unit 4512 can enhance the anti-interference ability of the circuit, so that the circuit can maintain a stable working state under external interference. In addition, the level range and driving capacity of the comparator output terminal can be flexibly adjusted by adjusting the parameters of the first voltage stabilizing unit 4511 and the second voltage stabilizing unit 4512, so as to adapt to different loads and circuit requirements.

[0046] For example, please refer to Figure 5 , and Figure 5 A circuit diagram of the AC frequency detection circuit is shown in FIG. 7. The first voltage stabilizing unit 4511 can be a resistor R7, and the second voltage stabilizing unit 4512 can be a resistor R8. One end of the resistor R7 is connected to the fourth output terminal, and the other end of the resistor R7 is connected to the positive electrode of the second DC power supply 50. One end of the resistor R8 is connected to the fourth output terminal, and the other end of the resistor R8 is grounded. That is, the fourth output terminal is connected to the pull-up resistor R7 and the pull-down resistor R8, respectively, so as to ensure that the fourth output terminal maintains a stable output state.

[0047] Further, please refer to Figure 4 and Figure 5 , it is shown that Figure 4 is another structural block diagram of the AC frequency detection circuit of the embodiment of the present application, Figure 5 is a circuit diagram of the AC frequency detection circuit of the embodiment of the present application. In some embodiments, the amplification circuit 452 includes a triode, the base of the triode is connected to the fourth output end, the emitter of the triode is grounded, and the collector of the triode is connected to the isolation circuit 453.

[0048] It needs to be understood that, please refer to Figure 5 , it is shown that the amplification circuit 452 includes a triode Q1; the amplification circuit 452 is arranged between the fourth output end and the isolation circuit 453, and is used for amplifying the signal output by the fourth output end, providing sufficient driving capability to drive the isolation circuit 453 to meet the input requirement of the isolation circuit 453, so that the isolation circuit 453 works normally. In addition, the triode can play a short-circuit protection role to prevent excessive current from damaging the subsequent circuit.

[0049] Further, please refer to Figure 4 and Figure 5 , it is shown that Figure 4 is another structural block diagram of the AC frequency detection circuit of the embodiment of the present application, Figure 5 is a circuit diagram of the AC frequency detection circuit of the embodiment of the present application. In some embodiments, the isolation circuit 453 includes an optical coupler, the optical coupler includes a third input end, a fourth input end, a second output end and a third output end, the third input end is connected to the amplification circuit 452, the fourth input end is connected to the second DC power supply 50, the second output end is grounded, and the third output end is configured as the first output end 43 and is connected to the third DC power supply 60.

[0050] Exemplarily, the isolation circuit 453 includes an optocoupler U2, the optocoupler U2 includes a light emitter and a light receiver, the light emitter can be a light emitting diode, and the light receiver can be a photo triode, wherein the negative electrode of the light emitting diode is configured to be connected to the collector of the triode Q1 in the amplification circuit 452 as the third input end, the positive electrode of the light emitting diode is configured to be connected to the second DC power supply 50 as the fourth input end, the emitter of the photo triode is configured to be grounded as the second output end, and the collector of the photo triode is configured to be connected to the positive electrode of the third DC power supply 60 as the third output end; in addition, the fourth input end is connected to the positive electrode of the second DC power supply 50 through a resistor R11, and the third output end is connected to the positive electrode of the third DC power supply 60 through a resistor R12, so as to ensure the safe operation and reliability of the light emitting diode and the photo triode, and at the same time, to protect the light emitting diode and the photo triode from being damaged by excessive current and voltage. It should be noted that the second DC power supply 50 is used to drive the light emitting diode to work, and the DC power supply connected to the light emitting diode and the DC power supply connected to the comparator can also be different DC power supplies, which can be designed according to actual scheme requirements; the third DC power supply 60 is used to drive the photo triode to work.

[0051] It should be understood that the isolation circuit 453 isolates the electrical connection between the frequency detection unit 40 and the subsequent circuit through the optocoupler U2, so as to prevent interference and protect the safety of the subsequent circuit. It should be noted that the third output end is configured to be connected to the third DC power supply 60 as the first output end 43, and the level signal output by the third output end is the level signal processed from the signal output by the fourth output end, so that the level signal output by the third output end is used as the signal for indicating the frequency corresponding to the AC power supply 20, and a more reliable and stable frequency indication signal can be obtained, thereby improving the accuracy and stability of the frequency measurement.

[0052] Please refer to Figure 5 In some embodiments, the level signals of the fourth output end and the first output end 43 can be detected respectively, wherein the level signals of the fourth output end and the first output end 43 are both square wave signals, and by detecting whether the level signals of the fourth output end and the first output end 43 both meet the expected square wave signal characteristics, it can be detected whether the circuit between the fourth output end and the first output end 43 is working normally, which helps to ensure the stability and reliability of the circuit.

[0053] Through the above technical solutions, the processing module 45 is configured to process the signal output by the comparison module 44, and provide a stable and reliable level signal for indicating the frequency corresponding to the AC power supply 20; and by using the stable voltage regulation circuit 451, the amplification circuit 452 and the isolation circuit 453, the detection of the frequency of the commercial power supply by the ordinary non-high-voltage MCU can be solved; the application realizes the detection of the frequency of the AC power supply by using the hardware circuit, and has the advantages of fast recognition speed, low cost and safety and reliability.

[0054] Please refer to Figure 4 and Figure 5 as shown, Figure 4 is another structural block diagram of the AC frequency detection circuit according to an embodiment of the application, Figure 5 is a circuit diagram of the AC frequency detection circuit according to an embodiment of the application. In some embodiments, the processing module 45 further comprises a first protection circuit 454, which comprises a diode, a positive electrode of the diode being connected to a base of a triode, and a negative electrode of the diode being connected to one end of a second voltage stabilizing unit 4512.

[0055] For example, the first protection circuit 454 comprises a diode D1, and in addition, the first protection circuit 454 further comprises a resistor R9, one end of the resistor R9 being connected to a positive electrode of the diode D1, and the other end of the resistor R9 being connected to a negative electrode of the diode D1.

[0056] Through the above technical solution, the first protection circuit 454 comprises the diode D1, and through the rapid recovery characteristic of the diode, the response speed and efficiency of the circuit can be improved. In addition, the first protection circuit 454 further comprises the resistor R9, which can play a role of current limiting in the circuit, for protecting the triode Q1, thereby helping to ensure the stability and reliability of the circuit.

[0057] Please refer to Figure 4 and Figure 5 as shown, Figure 4 is another structural block diagram of the AC frequency detection circuit according to an embodiment of the application, Figure 5 is a circuit diagram of the AC frequency detection circuit according to an embodiment of the application. In some embodiments, the processing module 45 further comprises a second protection unit, which comprises a first resistor, one end of the first resistor being connected to a third input end, and the other end of the first resistor being connected to a fourth input end.

[0058] For example, the first resistor is a resistor R10, one end of the resistor R10 being connected to the third input end, and the other end of the resistor R10 being connected to the fourth input end.

[0059] Through the above technical solution, the second protection unit avoids the leakage current of the triode in the off state from making the optocoupler misdirect on, thereby improving the stability of the circuit.

[0060] Correspondingly, the application further provides a battery management system, which comprises the AC frequency detection circuit according to the above embodiments. Therefore, the battery management system can have all the technical features and technical effects of the AC frequency detection circuit, which will not be described herein again.

[0061] In some embodiments, the alternating current frequency detection circuit proposed in the application can be applied but not limited to the battery management system of electric vehicles, and can also be applied to the fields of industrial automation, power systems, renewable energy, household appliances and medical devices, etc. to realize frequency monitoring.

[0062] The above describes in detail the alternating current frequency detection circuit and the battery management system provided by the application. The principles and implementation manners of the application are described by using specific examples. The above description of the embodiments is only used to help understand the method of the application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the application, the specific implementation manner and application range can be changed. In summary, the content of the specification should not be understood as a limitation of the application.

Claims

1. An AC frequency detection circuit, characterized in that: include: A collection unit, the collection unit comprising a first voltage divider module and a second voltage divider module, the first voltage divider module having a first end, a second end, and a third end, the first end being connected to one end of an AC power supply, the second end being connected to a first DC power supply, the second voltage divider module having a fourth end, a fifth end, and a sixth end, the fourth end being connected to the other end of the AC power supply, the fifth end being connected to the first DC power supply, the first DC power supply being configured to cause the third and sixth ends to output positive voltages; A frequency detection unit having a first input terminal, a second input terminal, and a first output terminal, wherein the first input terminal is connected to the third terminal, the second input terminal is connected to the sixth terminal, and the first output terminal is used to output a level signal corresponding to the AC power supply, wherein the level signal is used to indicate the frequency corresponding to the AC power supply.

2. The AC frequency detection circuit according to claim 1, wherein: The first voltage divider module includes a first voltage divider device and a second voltage divider device, one end of the first voltage divider device is configured as the first end, one end of the second voltage divider device is configured as the second end, the other end of the first voltage divider device is connected to the other end of the second voltage divider device, and the other end of the first voltage divider device and the other end of the second voltage divider device are connected to the third end; The second voltage divider module includes a third voltage divider device and a fourth voltage divider device, one end of the third voltage divider device is configured as the fourth end, one end of the fourth voltage divider device is configured as the fifth end, the other end of the third voltage divider device is connected to the other end of the fourth voltage divider device, and the other end of the third voltage divider device and the other end of the fourth voltage divider device are connected to the sixth end; The first voltage dividing module and the second voltage dividing module have the same voltage dividing ratio.

3. The AC frequency detection circuit according to claim 1, wherein: The frequency detection unit includes a comparison module, the comparison module includes a comparator, the comparator includes a non-phase input terminal, an inverting input terminal and a fourth output terminal, the non-phase input terminal is connected to the first input terminal, the inverting input terminal is connected to the second input terminal, and the fourth output terminal is connected to the first output terminal.

4. The AC frequency detection circuit according to claim 3, wherein: The frequency detection unit also includes a processing module, which includes a voltage stabilizing circuit, an amplifying circuit and an isolation circuit. The voltage stabilizing circuit and the amplifying circuit are both connected to the fourth output end, the isolation circuit is connected to the amplifying circuit, and the isolation circuit is also connected to the first output end.

5. The AC frequency detection circuit according to claim 4, characterized in that: The voltage stabilizing circuit includes a first voltage stabilizing unit and a second voltage stabilizing unit, one end of the first voltage stabilizing unit is connected to the fourth output end, the other end of the first voltage stabilizing unit is connected to the second DC power supply, one end of the second voltage stabilizing unit is connected to the fourth output end, and the other end of the second voltage stabilizing unit is grounded.

6. The AC frequency detection circuit according to claim 5, characterized in that: The amplifying circuit includes a transistor, a base of the transistor is connected to the fourth output terminal, an emitter of the transistor is grounded, and a collector of the transistor is connected to the isolation circuit.

7. The AC frequency detection circuit according to claim 6, characterized in that: The isolation circuit includes an optocoupler, which includes a third input terminal, a fourth input terminal, a second output terminal and a third output terminal. The third input terminal is connected to the amplifier circuit, the fourth input terminal is connected to the second DC power supply, the second output terminal is grounded, and the third output terminal is configured as the first output terminal and is connected to the third DC power supply.

8. The AC frequency detection circuit according to claim 6, wherein: The processing module further includes a first protection circuit, which includes a diode, wherein the anode of the diode is connected to the base of the transistor, and the cathode of the diode is connected to one end of the second voltage stabilizing unit.

9. The AC frequency detection circuit according to claim 7, wherein: The processing module further includes a second protection unit, which includes a first resistor, one end of the first resistor is connected to the third input end, and the other end of the first resistor is connected to the fourth input end.

10. A battery management system, characterized in that: The AC power frequency detection circuit comprises the AC power frequency detection circuit according to any one of claims 1 to 9.

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