An insulation detection method, system, and device based on frequency conversion small signal injection.

Abstract

This invention discloses an insulation detection method, system, and device based on frequency conversion small signal injection. The method generates a first sinusoidal AC voltage signal based on a first frequency and a second sinusoidal AC voltage signal based on a second frequency. A circuit model in the power battery system is preset. Based on the first sinusoidal AC voltage signal, a first voltage, a first current, and a first phase are obtained from the circuit model. The real part of a first impedance is calculated. Based on the second sinusoidal AC voltage signal, a second voltage, a second current, and a second phase are obtained from the circuit model. The real part of a second impedance is calculated. Based on the circuit model, a first equivalent value of the real part of the first impedance and a second equivalent value of the real part of the second impedance are calculated. Based on the first real part of the first impedance, the real part of the second impedance, the first equivalent value, and the second equivalent value, the insulation resistance value of the circuit model is calculated. This invention improves the insulation detection speed and enables insulation detection before high voltage is applied to the power system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of insulation detection, and in particular to an insulation detection method, system and device based on variable-frequency small-signal injection. BACKGROUND

[0002] The insulation resistance of a power battery system is measured by using an external resistance method. Since the external resistance method usually uses an unbalanced bridge for detection, the detection method has the problems of slow detection speed, influence of Y capacitor, high cost, and inability to realize insulation detection before high voltage on the power system. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the prior art. To this end, the present application provides an insulation detection method, system and device based on variable-frequency small-signal injection, which can improve the insulation detection speed and realize insulation detection before high voltage on the power system.

[0004] In a first aspect, the present application provides an insulation detection method based on variable-frequency small-signal injection, which comprises:

[0005] generating a first sinusoidal alternating voltage signal according to a first frequency and a second sinusoidal alternating voltage signal according to a second frequency;

[0006] presetting a circuit model in a power battery system, obtaining a first voltage, a first current and a first phase from the circuit model according to the first sinusoidal alternating voltage signal;

[0007] calculating a first impedance real part according to the first voltage, the first current and the first phase;

[0008] obtaining a second voltage, a second current and a second phase from the circuit model according to the second sinusoidal alternating voltage signal;

[0009] calculating a second impedance real part according to the second voltage, the second current and the second phase;

[0010] calculating a first equivalent value of the first impedance real part and a second equivalent value of the second impedance real part based on the circuit model;

[0011] calculating an insulation resistance value of the circuit model according to the first impedance real part, the second impedance real part, the first equivalent value and the second equivalent value.

[0012] Compared with the prior art, the first aspect of the present application has the following beneficial effects:

[0013] The method is used to improve the insulation detection speed, and the first sinusoidal alternating voltage signal is generated according to the first frequency, and the second sinusoidal alternating voltage signal is generated according to the second frequency; the circuit model in the power battery system is preset, the first voltage, the first current and the first phase are obtained from the circuit model according to the first sinusoidal alternating voltage signal; the first impedance real part is calculated according to the first voltage, the first current and the first phase; the second voltage, the second current and the second phase are obtained from the circuit model according to the second sinusoidal alternating voltage signal; the second impedance real part is calculated according to the second voltage, the second current and the second phase. In order to realize insulation detection before high voltage on the power system, based on the circuit model, the first equivalent value of the first impedance real part and the second equivalent value of the second impedance real part are calculated; the insulation resistance value of the circuit model is calculated according to the first impedance real part, the second impedance real part, the first equivalent value and the second equivalent value. The insulation resistance value is obtained under the first frequency and the second frequency of the sinusoidal alternating voltage signal, which can improve the insulation detection speed. The method does not need external resistance, and only needs to obtain the insulation resistance value under the first frequency and the second frequency of the sinusoidal alternating voltage signal in the preset circuit model in the power battery system, so as to realize insulation detection before high voltage on the power battery system. The method does not need to set a high voltage switch, can reduce the cost, and the method uses an alternating signal, which is not affected by Y capacitor.

[0014] According to some embodiments of the application, the first voltage, the first current and the first phase are obtained from the circuit model according to the first sinusoidal alternating voltage signal, including:

[0015] According to the first sinusoidal alternating voltage signal, the first voltage is obtained from the circuit model by a voltage detection module, the first current is obtained from the circuit model by a current detection module, and the first phase is obtained from the circuit model by a phase detection module.

[0016] According to some embodiments of the application, the first impedance real part is calculated according to the first voltage, the first current and the first phase, including:

[0017] The first input impedance is calculated according to the first voltage and the first current:

[0018]

[0019] Wherein, Z0 represents the first input impedance, V0 represents the first voltage, and I0 represents the first current;

[0020] The first impedance real part is calculated according to the first input impedance and the first phase:

[0021] Re0 = |Z0| x cos(θ0)

[0022] Where Re0 represents the real part of the first impedance, and θ0 represents the first phase.

[0023] According to some embodiments of the present invention, obtaining the second voltage, the second current, and the second phase from the circuit model based on the second sinusoidal AC voltage signal includes:

[0024] Based on the second sinusoidal AC voltage signal, a second voltage is obtained from the circuit model through a voltage detection module, a second current is obtained from the circuit model through a current detection module, and a second phase is obtained from the circuit model through a phase detection module.

[0025] According to some embodiments of the present invention, calculating the real part of the second impedance based on the second voltage, the second current, and the second phase includes:

[0026] Calculate the second input impedance based on the second voltage and the second current:

[0027]

[0028] Among them, Z n V represents the second input impedance. n Indicates the second voltage, I n This indicates the second current;

[0029] Calculate the real part of the second impedance based on the second input impedance and the second phase:

[0030] Re n =|Z n |×cos(θ n )

[0031] Among them, Re n θ represents the real part of the second impedance. n This indicates the second phase.

[0032] According to some embodiments of the present invention, calculating the first equivalent value of the real part of the first impedance based on the circuit model includes:

[0033] Based on the circuit model, the equivalent value of the first input impedance is calculated as follows:

[0034]

[0035] in, ω0 represents the angular frequency at the first frequency, ω0=2×π×f0, ω represents the angular frequency, and C represents the capacitance value in the circuit model. yThe capacitance value of Y in the circuit model is represented by , R represents the insulation resistance value in the circuit model, j represents the imaginary part of the impedance expression, and f0 represents the first frequency.

[0036] Based on the equivalent value of the first input impedance, a first equivalent value of the real part of the first impedance is obtained:

[0037]

[0038] According to some embodiments of the present invention, calculating the second equivalent value of the real part of the second impedance based on the circuit model includes:

[0039] Based on the circuit model, the equivalent value of the second input impedance is calculated as follows:

[0040]

[0041] in, ω0 represents the angular frequency at the second frequency, ω0=2×π×f0, ω represents the angular frequency, and C represents the capacitance value in the circuit model. y Let Y represent the capacitance value of the Y capacitor in the circuit model, R represent the insulation resistance value of the circuit model, and j represent the imaginary part of the impedance expression. f n f0 represents the second frequency;

[0042] Based on the equivalent value of the second input impedance, a second equivalent value of the real part of the second impedance is obtained:

[0043]

[0044] Secondly, embodiments of the present invention also provide an insulation detection system based on frequency conversion small signal injection, the insulation detection system based on frequency conversion small signal injection comprising:

[0045] A voltage signal generation unit is used to generate a first sinusoidal AC voltage signal according to a first frequency and a second sinusoidal AC voltage signal according to a second frequency.

[0046] The first data acquisition unit is used to preset the circuit model in the power battery system and obtain the first voltage, the first current and the first phase from the circuit model according to the first sinusoidal AC voltage signal.

[0047] The first impedance real part calculation unit is used to calculate the real part of the first impedance based on the first voltage, the first current and the first phase;

[0048] The second data acquisition unit is used to obtain the second voltage, the second current, and the second phase from the circuit model based on the second sinusoidal AC voltage signal.

[0049] The second impedance real part calculation unit is used to calculate the real part of the second impedance based on the second voltage, the second current and the second phase;

[0050] An equivalent value calculation unit is used to calculate, based on the circuit model, a first equivalent value of the real part of the first impedance and a second equivalent value of the real part of the second impedance;

[0051] An insulation resistance value acquisition unit is used to calculate the insulation resistance value of the circuit model based on the real part of the first impedance, the real part of the second impedance, the first equivalent value, and the second equivalent value.

[0052] Thirdly, embodiments of the present invention also provide an insulation detection device based on frequency conversion small signal injection, including at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, the instructions being executed by the at least one control processor to enable the at least one control processor to perform an insulation detection method based on frequency conversion small signal injection as described above.

[0053] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions for causing a computer to execute an insulation detection method based on frequency conversion small signal injection as described above.

[0054] It is understood that the beneficial effects of the second to fourth aspects compared with the related technologies are the same as the beneficial effects of the first aspect compared with the related technologies. Please refer to the relevant description in the first aspect above, which will not be repeated here. Attached Figure Description

[0055] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0056] Figure 1 This is a flowchart of an insulation detection method based on frequency conversion small signal injection according to an embodiment of the present invention;

[0057] Figure 2 This is a schematic diagram of the circuit model in a power battery system according to an embodiment of the present invention;

[0058] Figure 3 This is a structural diagram of an insulation detection system based on frequency conversion small signal injection according to an embodiment of the present invention. Detailed Implementation

[0059] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0060] In the description of this invention, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0061] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0062] In the description of this invention, it should be noted that, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0063] The external resistance method is used to measure the insulation resistance of the power battery system. However, since the external resistance method often uses an unbalanced bridge for detection, this detection method has problems such as slow detection speed, susceptibility to Y capacitors, high cost, and inability to perform insulation detection before high voltage is applied to the power system.

[0064] To address the aforementioned problems, this invention improves insulation detection speed by generating a first sinusoidal AC voltage signal based on a first frequency and a second sinusoidal AC voltage signal based on a second frequency. A circuit model of the power battery system is pre-defined. Based on the first sinusoidal AC voltage signal, a first voltage, a first current, and a first phase are obtained from the circuit model. The real part of a first impedance is calculated based on the first voltage, first current, and first phase. Similarly, based on the second sinusoidal AC voltage signal, a second voltage, a second current, and a second phase are obtained from the circuit model. The real part of a second impedance is then calculated based on the second voltage, second current, and second phase. To enable insulation detection before high voltage is applied to the power system, a first equivalent value of the real part of the first impedance and a second equivalent value of the real part of the second impedance are calculated based on the circuit model. The insulation resistance value of the circuit model is then calculated based on the first and second real impedances, the first equivalent value, and the second equivalent value. This invention improves insulation detection speed by obtaining the insulation resistance value under sinusoidal AC voltage signals at the first and second frequencies. This invention eliminates the need for external resistors. It obtains insulation resistance values ​​using a pre-defined circuit model within the power battery system and sinusoidal AC voltage signals at first and second frequencies, enabling insulation detection before high voltage is applied to the power battery system. Furthermore, this invention eliminates the need for a high-voltage switch, reducing costs. Since it uses AC signals, it is unaffected by the Y capacitor.

[0065] Reference Figure 1 This invention provides an insulation detection method based on frequency conversion small signal injection, which includes, but is not limited to, steps S100 to S700:

[0066] Step S100: Generate a first sinusoidal AC voltage signal according to a first frequency, and generate a second sinusoidal AC voltage signal according to a second frequency;

[0067] Step S200: Preset the circuit model in the power battery system, and obtain the first voltage, first current and first phase from the circuit model based on the first sinusoidal AC voltage signal;

[0068] Step S300: Calculate the real part of the first impedance based on the first voltage, the first current, and the first phase;

[0069] Step S400: Based on the second sinusoidal AC voltage signal, obtain the second voltage, second current, and second phase from the circuit model;

[0070] Step S500: Calculate the real part of the second impedance based on the second voltage, the second current, and the second phase;

[0071] Step S600: Based on the circuit model, calculate the first equivalent value of the real part of the first impedance and the second equivalent value of the real part of the second impedance;

[0072] Step S700: Calculate the insulation resistance value of the circuit model based on the real part of the first impedance, the real part of the second impedance, the first equivalent value, and the second equivalent value.

[0073] In steps S100 to S700 of some embodiments, this embodiment, in order to improve the insulation detection speed, generates a first sinusoidal AC voltage signal according to a first frequency and a second sinusoidal AC voltage signal according to a second frequency; a circuit model in the power battery system is preset, and a first voltage, a first current, and a first phase are obtained from the circuit model based on the first sinusoidal AC voltage signal; the real part of the first impedance is calculated based on the first voltage, the first current, and the first phase; a second voltage, a second current, and a second phase are obtained from the circuit model based on the second sinusoidal AC voltage signal; and the real part of the second impedance is calculated based on the second voltage, the second current, and the second phase. To enable insulation detection before high voltage is applied to the power system, a first equivalent value of the real part of the first impedance and a second equivalent value of the real part of the second impedance are calculated based on the circuit model; the insulation resistance value of the circuit model is calculated based on the real part of the first impedance, the real part of the second impedance, the first equivalent value, and the second equivalent value. This embodiment improves the insulation detection speed by obtaining the insulation resistance value under sinusoidal AC voltage signals at the first and second frequencies. This embodiment requires no external resistor. It only needs to obtain the insulation resistance value through a pre-defined circuit model of the power battery system and sinusoidal AC voltage signals at the first and second frequencies, enabling insulation detection before high voltage is applied to the power battery system. This embodiment eliminates the need for a high-voltage switch, reducing costs. Furthermore, this embodiment uses AC signals, making it unaffected by the Y capacitor.

[0074] In some embodiments, obtaining a first voltage, a first current, and a first phase from a circuit model based on a first sinusoidal AC voltage signal includes:

[0075] Based on the first sinusoidal AC voltage signal, the first voltage is obtained from the circuit model through the voltage detection module, the first current is obtained from the circuit model through the current detection module, and the first phase is obtained from the circuit model through the phase detection module.

[0076] It should be noted that the voltage detection module and current detection module in this embodiment use ADC (analog-to-digital converter). The first phase can be obtained by the phase detection module or by the phase difference between the first voltage phase and the first current phase. This embodiment does not make any specific limitation.

[0077] In some embodiments, calculating the real part of the first impedance based on the first voltage, the first current, and the first phase includes:

[0078] Calculate the first input impedance based on the first voltage and the first current:

[0079]

[0080] Where Z0 represents the first input impedance, V0 represents the first voltage, and I0 represents the first current;

[0081] Calculate the real part of the first impedance based on the first input impedance and the first phase:

[0082] Re0 = |Z0| × cos(θ0)

[0083] Where Re0 represents the real part of the first impedance and θ0 represents the first phase.

[0084] In some embodiments, obtaining a second voltage, a second current, and a second phase from a circuit model based on a second sinusoidal AC voltage signal includes:

[0085] Based on the second sinusoidal AC voltage signal, the second voltage is obtained from the circuit model through the voltage detection module, the second current is obtained from the circuit model through the current detection module, and the second phase is obtained from the circuit model through the phase detection module.

[0086] It should be noted that in this embodiment, the second phase can be obtained by a phase detection module or by the phase difference between the second voltage phase and the second current phase. This embodiment does not impose any specific limitations.

[0087] In some embodiments, calculating the real part of the second impedance based on the second voltage, the second current, and the second phase includes:

[0088] Calculate the second input impedance based on the second voltage and the second current:

[0089]

[0090] Among them, Z n Represents the second input impedance, V n Indicates the second voltage, I n Indicates the second current;

[0091] Calculate the real part of the second impedance based on the second input impedance and the second phase:

[0092] Re n =|Z n |×cos(θ n )

[0093] Among them, Re n θ represents the real part of the second impedance. n This indicates the second phase.

[0094] In some embodiments, based on a circuit model, calculating a first equivalent value of the real part of the first impedance includes:

[0095] Based on the circuit model, the equivalent value of the first input impedance is calculated as follows:

[0096]

[0097] in, ω0 represents the angular frequency at the first frequency, ω0=2×π×f0, where ω represents the angular frequency and C represents the capacitance value in the circuit model. y C represents the capacitance value of the Y capacitor in the circuit model. y =(C′) p +C″ p ) / / (C′ n +C″ n ), where Cp represents the parasitic capacitance between the positive terminal of the battery pack and ground, Cn represents the parasitic capacitance between the negative terminal of the battery pack and ground, / / represents parallel connection, R represents the insulation resistance value in the circuit model, j represents the imaginary part of the impedance expression, and f0 represents the first frequency;

[0098] Based on the equivalent value of the first input impedance, the first equivalent value of the real part of the first impedance is obtained:

[0099]

[0100] In some embodiments, calculating a second equivalent value of the real part of the second impedance based on a circuit model includes:

[0101] Based on the circuit model, the equivalent value of the second input impedance is calculated as follows:

[0102]

[0103] in, ω0 represents the angular frequency at the second frequency, ω0=2×π×f0, ω represents the angular frequency, and C represents the capacitance value in the circuit model. y Let Y represent the capacitance value of the Y capacitor in the circuit model, R represent the insulation resistance value of the circuit model, and j represent the imaginary part of the impedance expression. f n f0 represents the second frequency;

[0104] Based on the equivalent value of the second input impedance, the second equivalent value of the real part of the second impedance is obtained:

[0105]

[0106] To facilitate understanding by those skilled in the art, the following set of preferred embodiments is provided:

[0107] Reference Figure 2 A first sinusoidal AC voltage signal with a first frequency of f0 is generated in the variable frequency sinusoidal signal generator, and then passed through the circuit model of the preset power battery system (refer to...). Figure 2 Based on the first sinusoidal AC voltage signal, the first voltage V0 is obtained from the circuit model through the voltage detection module. Figure 2 As can be seen, one end of the voltage detection module is connected to the left end of capacitor C in the circuit model, and the other end is grounded. The first current I0 is obtained from the circuit model through the current detection module. Figure 2 As can be seen, the two ends of the current detection module are connected to the two ends of the resistor respectively, and the first phase θ0 is obtained from the circuit model through the phase detection module.

[0108] Calculate the first input impedance based on the first voltage and the first current:

[0109]

[0110] Where Z0 represents the first input impedance, V0 represents the first voltage, and I0 represents the first current;

[0111] Calculate the real part of the first impedance based on the first input impedance and the first phase:

[0112] Re0 = |Z0| × cos(θ0)

[0113] Where Re0 represents the real part of the first impedance and θ0 represents the first phase.

[0114] Switching the first frequency to f0, a second frequency of f is generated in the frequency converter sine wave generator. n The second sinusoidal AC voltage signal is used to obtain the second voltage V from the circuit model through the voltage detection module. n The second current I is obtained from the circuit model through the current detection module. n The second phase θ is obtained from the circuit model through the phase detection module. n .

[0115] Calculate the second input impedance based on the second voltage and the second current:

[0116]

[0117] Among them, Z n Represents the second input impedance, V n Indicates the second voltage, I n Indicates the second current;

[0118] Calculate the real part of the second impedance based on the second input impedance and the second phase:

[0119] Re n =|Z n |×cos(θ n )

[0120] Among them, Re n θ represents the real part of the second impedance. n This indicates the second phase.

[0121] Based on the circuit model, at the first frequency f0, the equivalent value of the first input impedance is calculated as follows:

[0122]

[0123] in, ω0 represents the angular frequency at the first frequency, ω0=2×π×f0, where ω represents the angular frequency and C represents the capacitance value in the circuit model. y denoted by Y, the capacitance value of the Y capacitor in the circuit model; R, the insulation resistance value of the circuit model; j, the imaginary part of the impedance expression; and f0, the first frequency.

[0124] Based on the equivalent value of the first input impedance, the first equivalent value of the real part of the first impedance is obtained:

[0125]

[0126] Based on the circuit model, when at the second frequency f n The equivalent value of the second input impedance is calculated as follows:

[0127]

[0128] in, ω0 represents the angular frequency at the second frequency, ω0=2×π×f0, ω represents the angular frequency, and C represents the capacitance value in the circuit model. y Let Y represent the capacitance value of the Y capacitor in the circuit model, R represent the insulation resistance value of the circuit model, and j represent the imaginary part of the impedance expression. f n f0 represents the second frequency;

[0129] Based on the equivalent value of the second input impedance, the second equivalent value of the real part of the second impedance is obtained:

[0130]

[0131] By combining the calculation equations for the real part of the first impedance, the real part of the second impedance, the first equivalent value of the real part of the first impedance, and the second equivalent value of the real part of the second impedance, the insulation resistance value of the circuit model is calculated as follows:

[0132] It should be noted that the variable frequency sine wave generator in this embodiment can use PWM modulation or PDM modulation; this embodiment does not impose a specific limitation. Furthermore, the circuit model in the preset power battery system can be modified according to actual needs; this embodiment does not impose a specific limitation.

[0133] Previously, the insulation resistance value R was calculated using the formula R = (R′) p +R″ p ) / / (R′ n +R″ n In this embodiment, Rp represents the insulation resistance between the positive terminal of the battery pack and ground, and Rn represents the insulation resistance between the negative terminal of the battery pack and ground. Since there is only one insulation resistance R in this embodiment, the circuit model is simplified. In this embodiment, the insulation resistance value can be obtained by switching two sinusoidal AC voltage signals of different frequencies, which improves the insulation detection speed. Furthermore, this embodiment does not require an external resistor; by pre-setting the circuit model in the power battery system and switching between the first and second frequency sinusoidal AC voltage signals, the insulation resistance value can be obtained, enabling insulation detection before high voltage is applied to the power battery system. This embodiment does not require a high-voltage switch, reducing costs, and because it uses AC signals, it is unaffected by the Y capacitor.

[0134] Reference Figure 3 This invention also provides an insulation detection system based on frequency conversion small signal injection. This insulation detection system includes a voltage signal generation unit 100, a first data acquisition unit 200, a first impedance real part calculation unit 300, a second data acquisition unit 400, a second impedance real part calculation unit 500, an equivalent value calculation unit 600, and an insulation resistance value acquisition unit 700, wherein:

[0135] The voltage signal generation unit 100 is used to generate a first sinusoidal AC voltage signal according to a first frequency and a second sinusoidal AC voltage signal according to a second frequency.

[0136] The first data acquisition unit 200 is used to preset the circuit model in the power battery system and obtain the first voltage, the first current and the first phase from the circuit model based on the first sinusoidal AC voltage signal.

[0137] The first impedance real part calculation unit 300 is used to calculate the real part of the first impedance based on the first voltage, the first current and the first phase;

[0138] The second data acquisition unit 400 is used to obtain the second voltage, the second current, and the second phase from the circuit model based on the second sinusoidal AC voltage signal.

[0139] The second impedance real part calculation unit 500 is used to calculate the real part of the second impedance based on the second voltage, the second current and the second phase;

[0140] The equivalent value calculation unit 600 is used to calculate, based on the circuit model, the first equivalent value of the real part of the first impedance and the second equivalent value of the real part of the second impedance.

[0141] The insulation resistance value acquisition unit 700 is used to calculate the insulation resistance value of the circuit model based on the real part of the first impedance, the real part of the second impedance, the first equivalent value, and the second equivalent value.

[0142] It should be noted that since the insulation detection system based on frequency conversion small signal injection in this embodiment is based on the same inventive concept as the insulation detection method based on frequency conversion small signal injection described above, the corresponding content in the method embodiment is also applicable to this system embodiment, and will not be described in detail here.

[0143] This invention also provides an insulation detection device based on frequency conversion small signal injection, comprising: at least one control processor and a memory for communicatively connecting to the at least one control processor.

[0144] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0145] The non-transient software program and instructions required to implement the insulation detection method based on frequency conversion small signal injection in the above embodiments are stored in memory. When executed by the processor, the insulation detection method based on frequency conversion small signal injection in the above embodiments is executed, for example, the method described above is executed. Figure 1 The method steps S100 to S700.

[0146] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0147] This invention also provides a computer-readable storage medium storing computer-executable instructions. These instructions, when executed by one or more control processors, cause the processors to perform an insulation detection method based on frequency conversion small-signal injection as described in the above-described method embodiments. For example, they can execute the methods described above. Figure 1 The functions of steps S100 to S700 in the method.

[0148] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0149] The above is a detailed description of the preferred embodiments of this application. However, the embodiments of this application are not limited to the above-described implementation methods. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the embodiments of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of the embodiments of this application.

Claims

1. An insulation detection method based on variable frequency small signal injection, characterized in that, The insulation detection method based on the variable-frequency small signal injection comprises: generating a first sinusoidal alternating voltage signal according to a first frequency and a second sinusoidal alternating voltage signal according to a second frequency; presetting a circuit model in a power battery system, obtaining a first voltage, a first current and a first phase from the circuit model according to the first sinusoidal alternating voltage signal; calculating a first impedance real part according to the first voltage, the first current and the first phase, comprising: calculating a first input impedance according to the first voltage and the first current: wherein, denotes the first input impedance, denotes the first voltage, denotes the first current; calculating the first impedance real part according to the first input impedance and the first phase: wherein, denotes the first impedance real part, denotes the first phase; obtaining a second voltage, a second current and a second phase from the circuit model according to the second sinusoidal alternating voltage signal; calculating a second impedance real part according to the second voltage, the second current and the second phase, comprising: calculating a second input impedance according to the second voltage and the second current: wherein, denotes the second input impedance, denotes the second voltage, denotes the second current; calculating the second impedance real part according to the second input impedance and the second phase: wherein, denotes the second impedance real part, denotes the second phase; calculating a first equivalent value of the first impedance real part and a second equivalent value of the second impedance real part based on the circuit model, comprising: calculating an equivalent value of the first input impedance based on the circuit model in the following way: wherein a= , b= , c= , denotes the angular frequency at the first frequency, , denotes the angular frequency, denotes the capacitance value in the circuit model, denotes the Y-capacitance value in the circuit model, denotes the insulation resistance value in the circuit model, denotes the imaginary part of the impedance expression, denotes the first frequency; obtaining the first equivalent value of the first impedance real part according to the equivalent value of the first input impedance: ； calculating an equivalent value of the second input impedance based on the circuit model in the following way: wherein a= , b= , c= , denotes the angular frequency at the second frequency, , denotes the angular frequency, denotes the capacitance value in the circuit model, denotes the Y-capacitance value in the circuit model, denotes the insulation resistance value in the circuit model, denotes the imaginary part of the impedance expression, , denotes the second frequency, denotes the second frequency; obtaining the second equivalent value of the second impedance real part according to the equivalent value of the second input impedance: ； calculating an insulation resistance value of the circuit model according to the first impedance real part, the second impedance real part, the first equivalent value and the second equivalent value.

2. The variable frequency small signal injection based insulation detection method of claim 1, wherein, The obtaining of the first voltage, the first current and the first phase from the circuit model according to the first sinusoidal alternating voltage signal comprises: obtaining the first voltage from the circuit model through a voltage detection module, obtaining the first current from the circuit model through a current detection module and obtaining the first phase from the circuit model through a phase detection module according to the first sinusoidal alternating voltage signal.

3. The variable frequency small signal injection based insulation detection method of claim 1, wherein, The obtaining of the second voltage, the second current and the second phase from the circuit model according to the second sinusoidal alternating voltage signal comprises: obtaining the second voltage from the circuit model through a voltage detection module, obtaining the second current from the circuit model through a current detection module and obtaining the second phase from the circuit model through a phase detection module according to the second sinusoidal alternating voltage signal.

4. An insulation detection system based on variable frequency small signal injection, characterized in that, The insulation detection system based on the variable-frequency small signal injection comprises: a voltage signal generation unit configured to generate a first sinusoidal alternating voltage signal according to a first frequency and a second sinusoidal alternating voltage signal according to a second frequency; a first data acquisition unit configured to preset a circuit model in a power battery system and obtain a first voltage, a first current and a first phase from the circuit model according to the first sinusoidal alternating voltage signal; The first impedance real part calculation unit is configured to calculate a first impedance real part according to the first voltage, the first current, and the first phase, and includes: calculating a first input impedance according to the first voltage and the first current; wherein, denotes the first input impedance, denotes the first voltage, denotes the first current; calculating the first impedance real part according to the first input impedance and the first phase; wherein, denotes the first impedance real part, denotes the first phase; The second data acquisition unit is configured to obtain a second voltage, a second current, and a second phase from the circuit model according to the second sinusoidal alternating voltage signal; The second impedance real part calculation unit is configured to calculate a second impedance real part according to the second voltage, the second current, and the second phase, and includes: calculating a second input impedance according to the second voltage and the second current; wherein, denotes the second input impedance, denotes the second voltage, denotes the second current; calculating the second impedance real part according to the second input impedance and the second phase; wherein, denotes the second impedance real part, denotes the second phase; The equivalent value calculation unit is configured to calculate a first equivalent value of the first impedance real part and a second equivalent value of the second impedance real part based on the circuit model, and includes: calculating an equivalent value of the first input impedance based on the circuit model in the following manner: wherein a= , b= , c= , denotes the angular frequency at the first frequency, , denotes the angular frequency, denotes the capacitance value in the circuit model, denotes the Y-capacitance value in the circuit model, denotes the insulation resistance value in the circuit model, denotes the imaginary part of the impedance expression, denotes the first frequency; obtaining the first equivalent value of the first impedance real part according to the equivalent value of the first input impedance; ； calculating an equivalent value of the second input impedance based on the circuit model in the following manner: wherein a= , b= , c= , denotes the angular frequency at the second frequency, , denotes the angular frequency, denotes the capacitance value in the circuit model, denotes the Y-capacitance value in the circuit model, denotes the insulation resistance value in the circuit model, denotes the imaginary part of the impedance expression, , denotes the second frequency, denotes the second frequency; obtaining the second equivalent value of the second impedance real part according to the equivalent value of the second input impedance; ； The insulation resistance value acquisition unit is configured to calculate an insulation resistance value of the circuit model according to the first impedance real part, the second impedance real part, the first equivalent value, and the second equivalent value.

5. An insulation detection device based on variable frequency small signal injection, characterized in that, The at least one control processor and the memory connected in communication with the at least one control processor; The memory stores instructions executable by the at least one control processor, and the instructions are executed by the at least one control processor to enable the at least one control processor to perform the insulation detection method based on variable-frequency small-signal injection according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the insulation detection method based on variable-frequency small-signal injection according to any one of claims 1 to 3.

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