Detection circuit and method of voltage divider circuit parameters and electric energy metering chip

Abstract

The present application belongs to the field of voltage detection technology, and provides a detection circuit for parameters of a voltage divider circuit, including a voltage divider circuit coupled with a first signal source having a first frequency, the voltage divider circuit including a first voltage divider, a second voltage divider, and a third voltage divider connected in series, and the detection circuit also includes: a voltage measurement module, a second signal source, and a measurement correction module; the voltage measurement module is used to detect the first signal component of the first frequency on the second voltage divider, and perform voltage measurement according to the first signal component; the measurement correction module is used to detect the second signal component of the second frequency on the second voltage divider, and determine whether the circuit parameters of the voltage divider circuit are abnormal according to the second signal component. The measurement correction module does not affect the normal operation of the voltage measurement module, and at the same time corrects the detection of the second signal to improve the detection accuracy.

Description

Technical Field

[0001] The present application belongs to the field of voltage detection technology, and in particular, relates to a detection circuit and method for voltage divider circuit parameters and an electric energy metering chip. Background Art

[0002] The development of intelligent power metering system requires the establishment of smart grid, which can help strengthen the automation and informatization of power grid, enhance the self-protection ability of power grid, and better maintain the operation and safety of power grid. Smart power metering system requires the realization of digitalization, standardization, networking and intelligence of power metering. Its digitalization refers to the use of new technologies to realize new digital power metering devices and achieve the accuracy and reliability of basic data; its intelligence refers to the ability to store users' electricity consumption information, working information of power meters (such as whether the metering accuracy has changed), and abnormal conditions of power meters (short circuit, open circuit, power theft, etc.) on the basis of accurate power metering data. Therefore, power meters with accurate automatic fault detection are an important component of smart power metering systems.

[0003] At present, in a voltage measuring device with fault detection, in order to realize the fault detection function of the voltage measuring device, a set of special detection circuits and a special detection signal are introduced. In this voltage measuring device with fault detection, the normal voltage signal measurement and the detection signal measurement share the same analog-to-digital converter (ADC), and then the voltage signal measurement value and the detection signal measurement value are generated in the digital signal processing unit, wherein the detection signal has the characteristics of high common mode / weak differential, and the above characteristics of the detection signal determine that when the ADC itself has a mismatch, the strong common mode part of the detection signal will be converted into a differential signal, which ultimately affects the measurement accuracy of the detection signal. If the measurement accuracy of the detection signal is to be improved, it is necessary to add a correction circuit in the ADC part to perform special correction on the detection signal, but because the detection signal and the measurement signal share the same ADC, this correction will affect the normal measurement of the voltage measuring device. Summary of the invention

[0004] The purpose of the present application is to provide a detection circuit, method and electric energy metering chip for parameters of a voltage divider circuit, aiming to solve the problem that the detection signal and the measurement signal of the existing voltage measurement circuit share the same ADC, and the correction of the detection signal will affect the normal measurement of the voltage measurement device.

[0005] A first aspect of an embodiment of the present application provides a detection circuit for a voltage divider circuit parameter, comprising a voltage divider circuit coupled to a first signal source having a first frequency, the voltage divider circuit comprising a first voltage divider, a second voltage divider, and a third voltage divider connected in series, the detection circuit further comprising:

[0006] a voltage measurement module, connected in parallel to both ends of the second voltage divider, and configured to detect a first signal component of the first frequency on the second voltage divider, and perform voltage measurement according to the first signal component;

[0007] a second signal source, inputted at a connection end of the second voltage divider and the third voltage divider, the second signal source having a second frequency; and

[0008] A measurement and correction module is connected in parallel at both ends of the second voltage divider, and is used to detect a second signal component of the second frequency on the second voltage divider, and determine whether a circuit parameter of the voltage divider circuit is abnormal according to the second signal component.

[0009] A second aspect of an embodiment of the present application provides a method for detecting parameters of a voltage divider circuit, comprising:

[0010] A first signal source with a first frequency is loaded at both ends of a voltage divider circuit; wherein the voltage divider circuit comprises a first voltage divider, a second voltage divider and a third voltage divider connected in series;

[0011] A second signal source with a second frequency is connected to a connection end of the second voltage divider and the third voltage divider;

[0012] Setting a measurement correction branch to detect a second signal component of the second frequency on the second voltage divider;

[0013] determining whether a circuit parameter of the voltage divider circuit is abnormal according to the second signal component, and correcting the circuit parameter of the voltage divider circuit when the circuit parameter is abnormal;

[0014] Setting a voltage measurement branch to detect a first signal component of the first frequency on the second voltage divider;

[0015] Voltage measurement is performed according to the first signal component and the corrected circuit parameters of the voltage divider circuit.

[0016] A third aspect of the embodiments of the present application provides an electric energy metering chip, the electric energy metering chip comprising the above-mentioned detection circuit; the voltage divider circuit is arranged outside the electric energy metering chip.

[0017] A fourth aspect of the embodiments of the present application provides an electric energy metering chip, including a voltage divider circuit, and the electric energy metering chip also includes the above-mentioned detection circuit.

[0018] The detection circuit and method of the voltage divider circuit parameters add a special measurement correction channel on the basis of the voltage measurement channel of the current measurement circuit with fault detection, and measure the measurement signal and the fault detection signal separately, so that the normal measurement of the measurement signal can be achieved without affecting the correction of the fault detection signal; an additional signal source is introduced into the measurement correction channel, and the known information of the AC signal source and certain switch timing information are used to locate whether the off-chip component has a fault, so as to achieve the function of accurately locating the fault source. It avoids the simultaneous introduction of the detection signal and the measurement signal into the voltage measurement channel, and the correction of the detection signal will affect the normal measurement of the voltage measurement device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a detection circuit for parameters of a conventional voltage divider circuit;

[0020] Figure 2 for Figure 1 The voltage waveform measured when the positive and negative input terminals of the ADC are in the detection circuit of the voltage divider circuit parameters shown, and the voltage waveform measured when the positive and negative input terminals of the ADC are swapped;

[0021] Figure 3 A schematic diagram of a module of a voltage divider circuit parameter detection circuit provided in the first embodiment of the present application;

[0022] Figure 4 A schematic diagram of the principle of a detection circuit for a voltage divider circuit parameter provided in the first embodiment of the present application;

[0023] Figure 5 for Figure 4 The waveforms of the measurement signal and the detection signal in the detection circuit of the voltage divider circuit parameters are shown;

[0024] Figure 6 A schematic diagram of the principle of a detection circuit for voltage divider circuit parameters provided in the second embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] See also Figure 1 , where V m is the voltage to be measured; is the voltage sampling network 100 (i.e., the voltage divider circuit) composed of R ext1 ( Figure 1 Reference number 202), R int1 ( Figure 1 Reference number 203), R int2 ( Figure 1The sampling network 100 is mainly used to attenuate the signal to be detected to within the safe input range of the ADC. The signal processing unit 200 is composed of an analog-to-digital conversion unit 205 and digital signal processing units 209 and 210. In the traditional scheme, the signal processing unit 200 is used as both a measurement signal processing unit and a detection signal processing unit. The detection signal source 300 is composed of timing switches S1 and S2 ( Figure 1 In the conventional scheme, the detection signal is passed through the sampling network 100 to generate a detection signal at the input end of the analog-to-digital conversion unit 205, and the detection signal is passed through the digital signal processing units 209 and 210 to generate a detection value.

[0027] When switch S2 is closed and S1 is open, assume that the frequency of the AC current source is f i , assuming that the voltage signal to be measured is V m is an AC signal with a frequency of f u , and f i ≠f u The voltage signal generated by the AC current source through the resistor divider at the ADC input is defined as U 0,fi_1 .

[0028] Calculate the differential voltage signal U generated by the AC current source through the resistor divider separately 0,fi_1_dm :

[0029]

[0030] Calculate the common-mode voltage signal U generated by the AC current source through the resistor divider separately 0,fi_1_cm :

[0031]

[0032] In voltage measurement, the voltage to be measured is generally attenuated to within the safe range of the ADC input voltage through the sampling network 100. ext1 Yuanda R int1 , commonly used R ext1 For 1M ohms, R int1 / R int2 is 1K ohms, so from the above formula we can see that the detection signal U 0,fi_1 It is a high common mode signal / weak differential signal, and its common mode part is 2000 times higher than the differential mode part.

[0033] Since the voltage measurement ADC itself has random mismatch, the detection signal U 0,fi_1 The common-mode part of the ADC is converted to the differential part, which results in a decrease in the measurement accuracy of the detection signal. cmdm,adcGenerally, it is around -60dBc (0.001 times). Due to the insufficient common-mode suppression of the ADC, the common-mode to differential-mode signal U of the detection signal 0,fi_1_cmdm The calculation is as follows:

[0034]

[0035] The common-mode-to-differential-mode signal U after the detection signal passes through the ADC 0,fi_1_cmdm is the detection signal differential signal U 0,fi_1_dm It is about twice as large as the original one, which seriously affects the measurement accuracy of the detection signal.

[0036] In order to improve the measurement accuracy of the detection signal, the general method is to calibrate by exchanging the positive and negative input terminals of the voltage measurement ADC, but this method will cause the measured voltage V m The phase information will be destroyed, thus affecting the normal voltage measurement. Figure 2 As shown, V m1 is the measured voltage waveform when the positive and negative input terminals of the ADC are not swapped; V m2 In order to improve the accuracy of the detection signal, the voltage waveform is measured when the detection signal accuracy is corrected by exchanging the positive and negative input terminals of the ADC. Figure 2 It can be seen that in the T1 / T2 period, when the detection signal accuracy is corrected by exchanging the positive and negative input terminals of the voltage measurement ADC, the measured voltage V m The phase information is destroyed (see V m2 waveform), thus affecting the final measurement value of the electric energy meter.

[0037] In the energy meter, the voltage V m It is used for energy measurement. Assuming that the current I is measured in the energy meter m and measure voltage V m In phase, in the T1+T2 time period, the electric energy value obtained without the detection signal accuracy correction is W1, and the electric energy value obtained with the detection signal accuracy correction is W2. The following calculates W1 / W2 respectively:

[0038] W1=V m1 I m (T1+T2)=V m I m (T1+T2)

[0039] W2=V m2 I m ·(T1+T 2) =V m I m ·T1+V m cosπ·I m T2 = V mI m (T1-T2)

[0040] It can be seen from the formulas W1 and W2 that when there is a detection signal accuracy correction, the measurement value of the electric energy meter cannot obtain the correct result. Therefore, the detection signal accuracy is corrected and the measurement voltage V m Voltage measurements cannot be made simultaneously.

[0041] See also Figure 3 The detection circuit of the voltage divider circuit parameter provided in the embodiment of the present application is based on the above-mentioned traditional solution, and the signal processing unit 200 used for both measurement signal processing and detection signal processing is split into two parts, namely, a voltage measurement module 30 used for measurement signal processing and a measurement correction module 50 used for detection signal processing, and R can be omitted. ext1 , R int1 The signal source connected between.

[0042] Therefore, the detection circuit of the voltage divider circuit parameters provided in the embodiment of the present application includes a voltage divider circuit 20 coupled to a first signal source 10 having a first frequency, the voltage divider circuit 20 includes a first voltage divider 21, a second voltage divider 22 and a third voltage divider 23 connected in series, and the detection circuit also includes a voltage measurement module 30, a second signal source 40 and a measurement correction module 50.

[0043] The voltage measurement module 30 is connected in parallel at both ends of the second voltage divider 22, and is used to detect the first signal component of the first frequency on the second voltage divider 22, and perform voltage measurement according to the first signal component; the second signal source 40 is input at the connection end of the second voltage divider 22 and the third voltage divider 23, and the second signal source 40 has a second frequency; the measurement correction module 50 is connected in parallel at both ends of the second voltage divider 22, and the measurement correction module 50 is used to detect the second signal component of the second frequency on the second voltage divider 22, and determine whether the circuit parameters of the voltage divider circuit 20 are abnormal according to the second signal component. At the same time, it can be determined whether the circuit parameters of the second signal source 40 (the feedback resistor used in the signal source generation circuit) are abnormal.

[0044] It is understandable that the second signal source 40 can also be connected through the first switch (not shown), and the measurement correction module 50 detects the second signal component when only the first switch is connected. The second signal source 40 is an AC current source. In addition, the measured voltage V m The frequency of the second signal source 40 is different from the frequency of the second signal source 40, and the second frequency is a non-integer multiple of the first frequency. mWhen the frequency is 50 Hz, the frequency of the second signal source 40 can be selected as 432 Hz. The second signal source 40 is mainly a current source generated by a combination of a reference voltage source, an operational amplifier, a current mirror tube and a feedback resistor. The internal circuit of the actual current source can control the output waveform of this current source to be an AC signal through a switch. The first voltage divider 21, the second voltage divider 22 and the third voltage divider 2323 are all circuits composed of at least one of a resistor, an inductor and a capacitor.

[0045] As an example, see Figure 4 The measurement correction module 50 includes an analog-to-digital conversion unit 51, digital signal processing units 52 and 53, and an error correction switch 54. The error correction switch 54 is used to flip the positive and negative of the signal connected to the measurement correction module 50 / ADC. Figure 5 When the measurement correction module 50 starts the correction function, the error correction switch 54 exchanges the positive and negative input terminals of the measurement correction module 50 at the T1 time period and the T2 time end. The detection signal at the input terminal of the measurement correction module 50 is named V edt , Figure 4 shows the V of the measurement correction module 50 edt Waveform and voltage measurement module 30 V m Waveform, from Figure 5 It can be seen that when the detection signal processing unit is V edt When the signal is corrected, the voltage measurement module 30 V m The signal is completely unaffected and can work normally, so it does not affect the final energy metering of the energy meter. The voltage measurement module 30 includes an analog-to-digital conversion unit 31 and digital signal processing units 32 and 33 .

[0046] In a further embodiment, the voltage measurement module 30 or the measurement correction module 50 is further used to correct the circuit parameters of the voltage divider circuit 20 according to the first signal component and the second signal component. The voltage measurement module 30 specifically performs voltage measurement according to the first signal component and the circuit parameters of the corrected voltage divider circuit.

[0047] See also Figure 6 , the detection circuit also includes a third signal source 60 with a third frequency. The third signal source 60 is input at the connection end between the first voltage divider 21 and the second voltage divider 22; the measurement and correction module 50 is also used to detect the third signal component of the third frequency on the second voltage divider 22, and determine whether the circuit parameters of the voltage divider circuit 20 are abnormal according to the third signal component. As another embodiment, the third signal source 60 and the second signal source 40 are the same signal source, and are input at the connection end between the first voltage divider 21 and the second voltage divider 22 through another branch.

[0048] As a preferred embodiment, the measurement and correction module 50 is specifically used to process the second signal component and the third signal component to obtain the amplitude value and phase value of the second signal component and the amplitude value and phase value of the third signal component, respectively, and determine whether the circuit parameters of the voltage divider circuit 20 are abnormal based on at least one of the change in the amplitude value of the second signal component, the change in the amplitude value of the third signal component, the change in the phase of the second signal component, and the change in the phase of the third signal component.

[0049] The third signal source 60 is also an AC current source. The frequencies of the second signal source 40 and the third signal source 60 may be the same or different, and the amplitudes may be the same or different; Figure 2 The second signal source 40 and the third signal source 60 may be provided by the same signal source circuit.

[0050] The third signal source 60 / the second signal source 40 can also be connected through a second switch (not shown), and the measurement correction module 50 detects the second signal component when only the second switch is connected. The third signal source 60 is an AC current source, and the measured voltage V m The frequency of the third signal source 60 is different from the frequency of the third signal source 60, and the third frequency is a non-integer multiple of the first frequency. m When the frequency is 50 Hz, the frequency of the third signal source 60 can be selected as 432 Hz. The third signal source 60 is mainly a current source generated by a combination of a reference voltage source, an operational amplifier, a current mirror tube and a feedback resistor. The internal circuit of the actual current source can control the output waveform of this current source to be an AC signal through a switch.

[0051] As an embodiment, the internal resistance feedback resistor used in the signal source circuit of the second signal source 40 and the third signal source 60 has the same temperature coefficient as the first voltage divider 21. At the same time, the temperature coefficient of the first voltage divider 21 of the measurement channel can be offset by the temperature coefficient of the feedback resistor. In this way, the feedback resistors of the second signal source 40 and the third signal source 60 can be placed outside the chip, mainly because an AC current source with an arbitrary temperature coefficient can be obtained by selecting an off-chip resistor with an arbitrary temperature coefficient.

[0052] The second voltage divider 22, the third voltage divider 23, the voltage measurement module 30 and the measurement correction module 50 are on-chip devices of the integrated circuit, and the feedback resistors used in the generation circuits of the first voltage divider 21, the second signal source 40 and the third signal source 60 are off-chip devices of the integrated circuit. The main reason for placing the feedback resistor of the second signal source 40 off-chip is that a current source with an arbitrary temperature coefficient can be obtained by selecting an off-chip resistor with an arbitrary temperature coefficient. At the same time, the temperature coefficient of the feedback resistor can be used to offset the first resistor R ext1 The temperature coefficient of

[0053] refer to Figure 6The voltage divider circuit 20 is not limited to the impedance type. For example, Z0, Z1, and Z2 in the following figure can be impedances such as resistors, capacitors, and inductors, or a combination thereof, such as impedances such as resistors and capacitors in parallel. If the sampling network includes components such as capacitors and inductors, the fault source can be located by simultaneously monitoring the amplitude and phase change of the detection signal.

[0054] An additional AC current source is introduced into the conventional voltage measurement channel, and the known information of the AC current source and certain switch timing information are used to locate whether the off-chip component has failed, so as to achieve the function of accurately locating the fault source. At the same time, through this voltage measurement device and voltage measurement method, the off-chip resistors with the same temperature coefficient are reasonably selected, so that the voltage measurement system can have a temperature compensation effect, which can further improve the voltage measurement accuracy and reduce the influence of temperature drift on the voltage measurement result.

[0055] The applied alternating current source signal may be various periodic signals, such as a sine wave signal, a square wave signal, a triangle wave signal, etc.

[0056] In addition, a method for detecting parameters of a voltage divider circuit is disclosed, comprising the following steps:

[0057] Step 1:

[0058] A first signal source having a first frequency is loaded at both ends of a voltage divider circuit; wherein the voltage divider circuit comprises a first voltage divider, a second voltage divider and a third voltage divider connected in series;

[0059] Step 2:

[0060] A second signal source with a second frequency is connected to a connection end of the second voltage divider and the third voltage divider;

[0061] Step 3:

[0062] Setting a measurement correction branch to detect a second signal component of the second frequency on the second voltage divider;

[0063] Step 4:

[0064] determining whether a circuit parameter of the voltage divider circuit is abnormal according to the second signal component, and correcting the circuit parameter of the voltage divider circuit when the circuit parameter is abnormal;

[0065] Step 5:

[0066] Setting a voltage measurement branch different from the measurement correction branch to detect the first signal component of the first frequency on the second voltage divider;

[0067] Step 6:

[0068] Voltage measurement is performed according to the first signal component and the corrected circuit parameters of the voltage divider circuit.

[0069] Among them, step three and step five can be performed simultaneously or in reverse order.

[0070] In a further embodiment, the measurement correction branch first performs a positive and negative flip on the received signal before determining whether the circuit parameter of the voltage divider circuit is abnormal based on the second signal component.

[0071] In a further embodiment, it also includes:

[0072] A third signal source having a third frequency is connected to the connection end between the first voltage divider and the second voltage divider;

[0073] The measurement correction branch detects the third signal component of the third frequency on the second voltage divider, and determines whether the circuit parameters of the voltage divider circuit are abnormal according to the third signal component.

[0074] In a further embodiment, in step 4, correcting the voltage divider circuit parameters when the circuit parameters are abnormal specifically comprises: correcting the circuit parameters of the voltage divider circuit according to the first signal component and the second signal component.

[0075] In a more specific embodiment, determining whether the parameter of the voltage divider circuit is abnormal according to the second signal component and the third signal component is specifically:

[0076] The second signal component and the third signal component are processed to obtain the amplitude value and phase value of the second signal component and the amplitude value and phase value of the third signal component respectively, and determine whether the circuit parameters of the voltage divider circuit are abnormal based on at least one of the change in the amplitude value of the second signal component, the change in the amplitude value of the third signal, the change in the phase of the second signal component, and the phase change of the third signal component.

[0077] The embodiment of the present application also provides an electric energy metering chip, which includes the aforementioned detection circuit. In the embodiment of the present application, the voltage divider circuit is arranged outside the electric energy metering chip. Specifically, the detection circuit is integrated inside the chip. At this time, the detection circuit inside the chip is not affected by the external environment. Further, the switch state of the first switch and the second switch can be pre-set in the voltage measurement module to automatically switch the switch state after startup.

[0078] The embodiment of the present application further proposes another electric energy metering chip, which includes a voltage divider circuit and the detection circuit as described above.

[0079] The detection circuit and method of the voltage divider circuit parameters add a special measurement correction channel on the basis of the voltage measurement channel of the current measurement circuit with fault detection, and measure the measurement signal and the fault detection signal separately, so that the fault detection signal can be corrected without affecting the normal measurement of the measurement signal; an additional signal source is introduced into the measurement correction channel, and the known information of the AC signal source and certain switch timing information are used to locate whether the off-chip component has a fault, so as to achieve the function of accurately locating the fault source. It avoids the simultaneous introduction of the detection signal and the measurement signal into the voltage measurement channel, and the correction of the detection signal will affect the normal measurement of the voltage measurement device.

[0080] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A detection circuit for a voltage divider circuit parameter, comprising a voltage divider circuit coupled to a first signal source having a first frequency, the voltage divider circuit comprising a first voltage divider, a second voltage divider and a third voltage divider connected in series, characterized in that: The detection circuit also includes: a voltage measurement module connected in parallel at both ends of the second voltage divider, used to detect a first signal component of the first frequency on the second voltage divider, and perform voltage measurement according to the first signal component, the voltage measurement module comprising a first analog-to-digital conversion module and a first digital signal processing module; a second signal source, inputted at a connection end of the second voltage divider and the third voltage divider, the second signal source having a second frequency; and a measurement and correction module connected in parallel at both ends of the second voltage divider, the measurement and correction module being used to detect a second signal component of the second frequency on the second voltage divider, and determining whether a circuit parameter of the voltage divider circuit is abnormal according to the second signal component, the measurement and correction module comprising a second analog-to-digital conversion unit, a second digital signal processing unit, and an error correction switch, the error correction switch being used to flip the positive and negative of a signal connected to the measurement and correction module / the second analog-to-digital conversion module; The measurement correction module is also used to correct the circuit parameters of the voltage divider circuit according to the first signal component and the second signal component.

2. The detection circuit according to claim 1, characterized in that: The detection circuit also includes: A third signal source having a third frequency inputted at a connection end between the first voltage divider and the second voltage divider; The measurement and correction module is further used to detect a third signal component of the third frequency on the second voltage divider, and determine whether a circuit parameter of the voltage divider circuit is abnormal according to the third signal component.

3. The detection circuit according to claim 2, characterized in that: The measurement and correction module is specifically used to process the second signal component and the third signal component to obtain the amplitude value and phase value of the second signal component and the amplitude value and phase value of the third signal component, respectively, and determine whether the circuit parameters of the voltage divider circuit are abnormal based on at least one of the change in the amplitude value of the second signal component, the change in the amplitude value of the third signal component, the change in the phase of the second signal component, and the change in the phase of the third signal component.

4. The detection circuit according to claim 2, characterized in that: The second signal source and the third signal source are alternating current sources; the second frequency and the third frequency are the same or different, and are both non-integer multiples of the first frequency.

5. The detection circuit according to claim 1, characterized in that: The first voltage divider, the second voltage divider and the third voltage divider are circuits composed of at least one of a resistor, an inductor and a capacitor.

6. The detection circuit according to claim 1, characterized in that: The second voltage divider, the third voltage divider, the voltage measurement module and the measurement correction module are on-chip devices of the integrated circuit, and the first voltage divider and the feedback resistor used in the second signal source generation circuit are off-chip devices of the integrated circuit.

7. A method for detecting parameters of a voltage divider circuit, applied to the detection circuit according to any one of claims 1 to 6, characterized in that: include: A first signal source with a first frequency is loaded at both ends of a voltage divider circuit; wherein the voltage divider circuit comprises a first voltage divider, a second voltage divider and a third voltage divider connected in series; A second signal source with a second frequency is connected to a connection end of the second voltage divider and the third voltage divider; Setting a measurement correction branch to detect a second signal component of the second frequency on the second voltage divider; The measurement correction branch determines whether the circuit parameters of the voltage divider circuit are abnormal according to the second signal component, and corrects the circuit parameters of the voltage divider circuit when the circuit parameters are abnormal; Setting a voltage measurement branch to detect a first signal component of the first frequency on the second voltage divider; Voltage measurement is performed according to the first signal component and the corrected circuit parameters of the voltage divider circuit.

8. The detection method according to claim 7, characterized in that The measurement correction branch first performs a positive and negative flip on the received signal before determining whether the circuit parameter of the voltage divider circuit is abnormal according to the second signal component.

9. The detection method according to claim 7, characterized in that: The specific method of correcting the voltage divider circuit parameters when the circuit parameters are abnormal is as follows: The circuit parameters of the voltage divider circuit are corrected according to the first signal component and the second signal component.

10. The detection method according to claim 7, 8 or 9, characterized in that: Also includes: A third signal source having a third frequency is connected to the connection end between the first voltage divider and the second voltage divider; The measurement correction branch detects the third signal component of the third frequency on the second voltage divider, and determines whether the circuit parameters of the voltage divider circuit are abnormal according to the third signal component.

11. The detection method according to claim 10, characterized in that: The determining whether the parameter of the voltage divider circuit is abnormal according to the second signal component and the third signal component is specifically: The second signal component and the third signal component are processed to obtain the amplitude value and phase value of the second signal component and the amplitude value and phase value of the third signal component respectively, and determine whether the circuit parameters of the voltage divider circuit are abnormal based on at least one of the change in the amplitude value of the second signal component, the change in the amplitude value of the third signal, the change in the phase of the second signal component, and the change in the phase of the third signal component.

12. An electric energy metering chip, characterized in that: The electric energy metering chip comprises the detection circuit according to any one of claims 1 to 6; the voltage divider circuit is arranged outside the electric energy metering chip.

13. An electric energy metering chip, comprising a voltage divider circuit, characterized in that: The electric energy metering chip further comprises a detection circuit as claimed in any one of claims 1 to 6.

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