CN111208328A - Detection circuit and electric energy metering chip and equipment based on detection circuit - Google Patents
Detection circuit and electric energy metering chip and equipment based on detection circuit Download PDFInfo
- Publication number
- CN111208328A CN111208328A CN201811398987.1A CN201811398987A CN111208328A CN 111208328 A CN111208328 A CN 111208328A CN 201811398987 A CN201811398987 A CN 201811398987A CN 111208328 A CN111208328 A CN 111208328A
- Authority
- CN
- China
- Prior art keywords
- signal
- detection circuit
- coupled
- circuit
- sampling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
Abstract
The application relates to the technical field of electric energy metering, and discloses a detection circuit, and an electric energy metering chip and equipment based on the detection circuit. The circuit comprises a reference current source, a sampling circuit, a self-adaptive filtering module, a signal processing module, a disconnection working condition detection circuit and protective measures taken aiming at the working conditions. The self-adaptive filtering module is adopted, metering errors caused by the change of the frequency of the reference current source or interference in a sampling signal are greatly reduced, the measurement precision of the detection circuit is improved, meanwhile, the detection circuit is designed for various wire breakage working conditions in the detection circuit, wire breakage protective measures are correspondingly designed, and the reliability and the safety of the operation of a metering system are improved.
Description
Technical Field
The application relates to the technical field of electric energy metering, in particular to a detection circuit and an electric energy metering chip and equipment based on the detection circuit.
Background
In the electric energy measurement of the intelligent electric energy meter, generally, a power grid current and voltage signal are converted into a voltage signal meeting an input voltage safety range of an ADC (Analog to Digital Converter) through the electric energy meter, a sensor and a sampling network, and a Digital signal converted by the ADC is input to a Digital processing unit for power calculation and metering.
In a power supply system, the accuracy of an electric energy metering device is directly related to economic benefits of both power supply and power utilization, although the electric energy metering equipment can be calibrated by a standard meter with a higher precision grade before leaving a factory to obtain the standard specified accuracy grade of the electric energy metering equipment, after the electric energy metering equipment is installed on site, the electric energy metering equipment can generate metering errors due to various reasons such as external environment change, component aging and invalidation and the like. Whether the electric energy metering equipment can produce the metering error at the scene, whether can take measures to reduce the metering error, whether metering circuit trouble can in time discover, is the problem that supply and power consumption both sides are focused on.
At present, a manager of an electric energy meter adopts a method for periodically and offline sampling and detecting errors of the electric energy meter in the whole life cycle management process after the electric energy meter is connected with a network, the precision change of each connected electric energy metering device cannot be timely found through real-time online monitoring, the electric energy metering circuit fault is self-diagnosed, the errors of electric energy charging are caused, and unnecessary troubles and losses are brought to power supply and utilization parties.
Disclosure of Invention
The application aims to provide a detection circuit, and an electric energy metering chip and equipment based on the detection circuit, so that the metering error caused by the change of the frequency of a reference current source or the existence of an interference signal in a sampling signal is greatly reduced, and the metering precision and the reliability of a metering system are improved.
In order to solve the above problem, the present application discloses a detection circuit including:
a reference current source for outputting a second frequency alternating current signal;
a sampling circuit coupled to the reference current source, the sampling circuit further coupled to a first signal source that outputs a first frequency ac signal, the sampling circuit outputting a sampling signal of a mixed signal of the first frequency ac signal and the second frequency ac signal;
the adaptive filtering module comprises an adaptive filter and a subtracter, wherein the sampling circuit is respectively coupled to an input end of the adaptive filter and a first input end of the subtracter, an output end of the adaptive filter is coupled to a second input end of the subtracter, the adaptive filter is used for filtering the sampling signal to obtain the first frequency alternating current signal, and the subtracter is used for subtracting the sampling signal of the first input end and the first frequency alternating current signal of the second input end and then outputting the second frequency alternating current signal;
and the signal processing module is coupled with the self-adaptive filtering module and is used for processing the second frequency alternating current signal output by the self-adaptive filtering module.
In a preferred embodiment, before the adaptive filter is used, the order parameters of the adaptive filter are calculated and fixed, and the order parameters are determined based on the steepest descent method.
In a preferred embodiment, the parameters of each order are determined based on a least mean square method, and according to an iterative formula of the parameters of each order of the FIR filter, the mean square expected value of the output of the adder tends to be minimum through multiple iterations, so as to obtain the parameters of each order of the adaptive filter.
In a preferred embodiment, the adaptive filter further comprises an analog-to-digital converter coupled to the sampling circuit, the analog-to-digital converter being coupled to the adaptive filter module.
In a preferred embodiment, the apparatus further comprises a first detection module coupled to two input terminals of the analog-to-digital converter, the first detection module is coupled to the signal processing module, and the first detector is configured to detect whether an abnormal ac signal exists in signals at the first input terminal and the second input terminal of the analog-to-digital converter.
In a preferred embodiment, the method further comprises the following steps:
an RC filter having an input coupled to the sampling circuit, an output coupled to the input of the analog-to-digital converter;
a first impedance element coupled across the sampling circuit.
In a preferred embodiment, the method further comprises the following steps:
the input end of the second detection module is coupled with the reference current source, and the output end of the second detection module is coupled with the signal processing module and used for detecting whether the reference current source has an open-circuit fault or not and feeding back the open-circuit fault to the signal processing module;
a second impedance element having one end coupled to the reference current source and the other end coupled to ground.
In a preferred example, the sampling circuit uses a manganin or current transformer for sampling.
The application also discloses an electric energy metering chip which comprises the detection circuit as described in the foregoing.
The application also discloses an electric energy metering device, which comprises the electric energy metering chip described in the foregoing.
In the embodiment of the application, the detection circuit comprises a reference current source, a sampling circuit, a self-adaptive filtering module, a signal processing module, a disconnection working condition detection circuit and a protection measure adopted by the working condition, and the detection circuit has the following advantages:
the adaptive filtering module comprises an adaptive filter and a subtracter:
(1) before the adaptive filter is used, each order parameter of the adaptive filter needs to be calculated and fixed, the each order parameter is determined based on a steepest descent method, further, the each order parameter is determined based on a least mean method, and according to an iterative formula of each order parameter of the FIR filter, the mean square expected value of the output of the adder tends to be minimum through multiple iterations, so that each order parameter of the adaptive filter is obtained;
(2) the self-adaptive filter comprises an FIR filter with adjustable order, when the target signal is closed and only an alternating current signal exists, the parameters of each order of the FIR filter are calculated through the self-adaptive filtering algorithm, the output of the adder is zero, and the parameters of each order of the filter are fixed; when a target signal is opened and only alternating current signals pass (all sampling signals pass at the moment), the signals pass through the adaptive filter with fixed parameters of each order, and the target signal can be accurately obtained after subtraction is carried out on all sampling signals and the sampling signals except the target signal through the subtracter;
(3) when the target signal or the sampling signal is interfered by an external signal or changes, the adaptive filtering algorithm can recalculate the optimal parameters of the adaptive filter, so as to obtain an accurate target signal;
because the self-adaptive filtering module physically separates the reference current source by filtering other signals, the frequency of the reference current source before and after separation cannot be responded, and the change of the frequency of the reference current source cannot cause metering error; if there is an interference signal in the sampled signal, the adaptive filtering module may recalculate the optimal parameters of the adaptive filter so that the interference signal is within the filtering range of the adaptive filter, and thus the frequency f1 of the reference current source is not affected.
Moreover, by adopting the self-adaptive filtering module, the metering error of the detection circuit caused by the change of the frequency of the reference current source or the interference signal in the sampling signal is greatly reduced, and the measurement precision and the reliability of the detection circuit are improved.
Two ends of the sampling circuit are connected with an RC filter:
the two ends of the sampling circuit are connected to the RC filter, so that a sampling signal passes through the RC filter before being input into the adaptive filter, the RC filter adopts a differential structure, common-mode interference in the signal can be effectively inhibited, and metering errors caused by signal interference of the detection circuit are greatly reduced.
Thirdly, detecting and taking emergency protection measures aiming at the wire breakage working condition:
the method is characterized in that a reference current source disconnection detection and protection measure, a sampling line disconnection detection and protection measure and a live wire disconnection detection and protection measure are respectively introduced, a detection circuit and a protection circuit are designed according to the disconnection working condition, and the reliability and the safety of the operation of a metering system where the detection circuit is located are improved to a great extent.
The present specification describes a number of technical features distributed throughout the various technical aspects, and if all possible combinations of technical features (i.e. technical aspects) of the present specification are listed, the description is made excessively long. In order to avoid this problem, the respective technical features disclosed in the above summary of the invention of the present application, the respective technical features disclosed in the following embodiments and examples, and the respective technical features disclosed in the drawings may be freely combined with each other to constitute various new technical solutions (which are considered to have been described in the present specification) unless such a combination of the technical features is technically infeasible. For example, in one example, the feature a + B + C is disclosed, in another example, the feature a + B + D + E is disclosed, and the features C and D are equivalent technical means for the same purpose, and technically only one feature is used, but not simultaneously employed, and the feature E can be technically combined with the feature C, then the solution of a + B + C + D should not be considered as being described because the technology is not feasible, and the solution of a + B + C + E should be considered as being described.
Drawings
FIG. 1 is a circuit block diagram of a detection circuit according to a first embodiment of the present application
FIG. 2(a) is a schematic block diagram of an adaptive filtering module according to a first embodiment of the present application
FIG. 2(b) is a schematic block diagram of an adaptive filter module according to a first embodiment of the present application in a training state
FIG. 2(c) is a schematic block diagram of an adaptive filtering module according to the first embodiment of the present application in an operating state
FIG. 3 is a functional block diagram of an adaptive filtering module according to the present application
FIG. 4 is a functional block diagram of a parameter fixing algorithm for an FIR transversal filter according to the present application
FIG. 5 is an embodiment of an RC filter according to the present application
FIG. 6 is a diagram of an exemplary current sensing device with current self-calibration functionality according to the present application
FIG. 7 is a diagram of one embodiment of a current sensing device with current self-calibration functionality according to the present application
Detailed Description
In the following description, numerous technical details are set forth in order to provide a better understanding of the present application. However, it will be understood by those skilled in the art that the technical solutions claimed in the present application may be implemented without these technical details and with various changes and modifications based on the following embodiments.
Description of partial concepts:
submerging: when the electric energy meter is operated or checked, the phenomenon that the dial plate still continuously rotates when only voltage is applied and the load current is zero often occurs, and the phenomenon is called voltage shunt running, which is called shunt running for short.
Steepest descent method: also known as gradient, which is the oldest one of the analytical methods, other analytical methods are either variants thereof or are inspired by it, and thus are the basis of optimization methods. The steepest descent method is an important analytical method for the unconstrained nonlinear programming problem minf (x) of the n-ary function, and the research on the steepest descent method principle and the algorithm implementation thereof have extremely important significance to us.
Least mean square algorithm: the least mean square algorithm, called LMS algorithm for short, is an improved algorithm of steepest descent algorithm, and is an optimized extension after applying a fast descent method on the wiener filtering theory, the algorithm does not need to know the statistical characteristics of input signals and expected signals, and the weight coefficient of the current moment is obtained by the weight coefficient of the previous moment and a proportional term of a negative mean square error gradient. The method has the characteristics of low computational complexity, good convergence in an environment with stable signals, unbiased convergence of expected values to wiener solutions, realization of stability of the algorithm by using limited precision and the like, so that the LMS algorithm becomes the algorithm with the best stability and the most wide application in the self-adaptive algorithm.
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
A first embodiment of the present application relates to a detection circuit, a block circuit diagram of which is shown in fig. 1, the detection circuit including: (1) a reference current source for outputting a second frequency alternating current signal; (2) a sampling circuit coupled to the reference current source, the sampling circuit further coupled to a first signal source that outputs a first frequency ac signal, the sampling circuit outputting a sampling signal that is a mixed signal of the first frequency ac signal and the second frequency ac signal; (3) the adaptive filtering module comprises an adaptive filter and a subtracter, wherein the sampling circuit is respectively coupled to an input end of the adaptive filter and a first input end of the subtracter, an output end of the adaptive filter is coupled to a second input end of the subtracter, the adaptive filter is used for filtering the sampling signal to obtain the first frequency alternating current signal, and the subtracter is used for subtracting the sampling signal of the first input end and the first frequency alternating current signal of the second input end and then outputting the second frequency alternating current signal; (4) and the signal processing module is coupled with the self-adaptive filtering module and is used for carrying out signal processing on the second frequency alternating current signal output by the self-adaptive filtering module.
Alternatively, as shown in fig. 2, the adaptive filtering module includes an adaptive filter and a subtractor, and before the adaptive filter is used, the parameters of each order of the adaptive filter need to be calculated and fixed.
Alternatively, as shown in fig. 2, the adaptive filtering module includes two working states: a training state and a working state; wherein the training state is used for calculating and fixing parameters of the adaptive filtering.
Specifically, taking the first signal source as an electric network as an example, when the adaptive filtering module is in a training state, the connection mode of the adaptive filtering module is as shown in fig. 2(b), the target signal is turned off, only a 50Hz electric network signal is added to the input signal, and the output end of the adaptive filtering module is made to be zero through training of the adaptive filter; after the training operation is completed, the adaptive filtering module can normally operate (i.e., is in an operating state), the connection mode is shown in fig. 2(c), the input signal is a mixed signal of a target signal and a 50HZ grid signal, the mixed signal is filtered by an adaptive filter, other signals only remain signals related to the 50HZ grid, and then the signals are output to the second input end of the subtractor, and finally, the signals of the second input end are subtracted from the mixed signal of the first input end of the subtractor, so that the target signal is obtained.
Alternatively, the training state of the adaptive filter may be controlled by setting a switch at the target signal output.
Alternatively, the order parameters of the adaptive filter are determined based on the steepest descent method.
Optionally, the order parameters of the adaptive filter are determined based on a least mean method.
Alternatively, as shown in fig. 3, the adaptive filter is an order-adjustable FIR filter, and the desired mean square value of the output of the subtractor in the adaptive filtering module may be minimized through multiple iterations according to an iteration formula of each order parameter, so as to obtain each order parameter of the adaptive filter.
One embodiment of the adaptive filter with fixed parameters of each order is as follows: after an adaptive filtering module (comprising a subtracter and an adaptive filter) is connected with a sampling circuit and a reference current source, the reference current source is closed and only an alternating current signal passes through the adaptive filter, so that the output of the adder is zero, then according to an iterative formula of each order of parameters, the mean square expected value of the output of the adder tends to be minimum through multiple iterations to obtain an optimal parameter, and then each order of parameters of the filter are fixed.
One embodiment of the adaptive filter of the present application is a FIR transversal filter, the internal structure of which is shown in fig. 4, wherein,
the weight sequence is as follows: h (k) ═ h1(k),h2(k),…,hM(k)]T(1)
Return toQuantity: x (k) ═ x (k), x (k-1), …, x (k-M +1)]T(2)
According to equations (1) and (2), the FIR transversal filter output is:
it should be understood that the iterative formula of each order of parameters described in the present application is set by the algorithm module according to the situation.
Optionally, the present application is to determine the magnitude of the metering error of the detection circuit according to a change of information (e.g., amplitude, phase, etc.) of a target signal (e.g., a second frequency signal output by a reference current source) from a preset calibration value by a signal processing module.
Optionally, in the present application, when the sampling signal is interfered by an external signal or changes itself, the adaptive filtering module recalculates parameters of each order of the adaptive filter through "training", so as to obtain an accurate target signal.
Optionally, the detection circuit according to the present application further includes an analog-to-digital converter coupled to the sampling circuit, the analog-to-digital converter being coupled to an input of the adaptive filtering module, and the analog-to-digital converter performing analog-to-digital conversion on the sampling signal output by the sampling circuit.
Optionally, the detection circuit according to the present application further includes a first detection module coupled to two input terminals of the analog-to-digital converter, the first detection module being coupled to the signal processing module, and the first detector being configured to detect whether an abnormal ac signal (e.g., a jamming signal) is present in the signals at the first input terminal and the second input terminal of the analog-to-digital converter.
Optionally, the first detection module further includes a detector and a detection algorithm, in order to prevent erroneous judgment caused by interference signals existing at the first input end and the second input end of the analog-to-digital converter, the detection algorithm may reliably detect abnormal alternating-current signals at the first input end and the second input end of the analog-to-digital converter to judge whether the live wire of the detection circuit is actually disconnected, and feed the abnormal alternating-current signals back to the signal processing module for processing, or the signal processing module transmits the judgment result to the maintenance staff of the electricity meter through communication with the outside.
Optionally, the detection circuit related to the present application further includes an RC filter having an input end coupled to the sampling circuit, and an output end of the RC filter is coupled to the input end of the analog-to-digital converter, and the RC filter can effectively suppress common mode interference in the signal, thereby improving the accuracy of the measurement of the detection circuit.
An embodiment of the RC filter in the present application is composed of a resistor R1, a capacitor C1, a resistor R2, and a capacitor C2, as shown in fig. 5, and adopts a symmetric differential form, which can effectively suppress common mode interference in signals.
Optionally, the detection circuit related to the present application further includes a first impedance element coupled to two ends of the sampling circuit, and the first impedance element may hide a signal when a sampling line of the detection circuit is disconnected or dropped, so as to prevent occurrence of phenomena of serious distortion in metering and multiple electricity charges.
Optionally, the detection circuit according to the present application further comprises a second detection module and a second impedance element; the input end of the second detection module is coupled with the reference current source, the output end of the second detection module is coupled with the signal processing module, and the second detection module monitors the output voltage condition of the reference current source at any moment, is used for detecting whether the reference current source has an open-circuit fault or not and feeds back the open-circuit fault to the signal processing module; the second impedance element is coupled with the reference current source at one end and is coupled with the ground at the other end, and the first impedance element provides a follow current loop when the reference current source has an open circuit fault, so that the function of protection is achieved.
It should be understood by those skilled in the art that, since the current self-calibration theory is constant based on the reference current source, once the reference current source is open, the system will change the sampling resistance involved in the sampling circuit to a small value, so as to calibrate the first signal source (such as a power grid) to a large value, which is the most intuitive result in overcharging of the power meter in terms of metering of the power meter, and thus, the loss is caused to the user. In addition, the open circuit of the current source will cause uncontrollable damage to the system.
Alternatively, the impedance element referred to in the present application may be a resistor, a capacitor, or an inductor.
Optionally, the sampling circuit in the detection circuit related to the present application uses a manganin or current transformer for sampling.
The function of the signal processing module in the present application is versatile and scalable, optionally, the signal processing module is used to calculate the current signal of the detection circuit; optionally, the signal processing module is configured to compare a change of a reference current source output signal (e.g., an amplitude) with respect to a preset calibration value to determine a measurement error of the detection circuit, so as to fix each order parameter of the adaptive filter again; optionally, the signal processing module is configured to receive and process a disconnection condition; optionally, the signal processing module communicates with the outside.
The second embodiment of the present application relates to an electric energy metering chip, which includes the detection circuit according to the first embodiment of the present application and has the beneficial effects of the detection circuit.
When the electric energy metering chip is used, the electric energy metering chip can accurately obtain a target signal through the detection circuit, if an alternating current signal is interfered by an external signal, the interference can be filtered through an RC filter with a differential structure accessed by the sampling circuit, or if the target signal or the target signal changes, an adaptive filtering module adopted by the detection circuit can recalculate the optimal parameter of the adaptive filter, so that an accurate target signal is obtained; therefore, the metering error of the electric energy metering chip is greatly reduced.
The third embodiment of the present application relates to an electric energy metering device that includes the detection circuit according to the first embodiment of the present application and has the advantageous effects of the detection circuit.
When the electric energy metering device is used, the electric energy metering device can accurately obtain a target signal through the detection circuit, if an alternating current signal is interfered by an external signal, the interference can be filtered through an RC filter with a differential structure accessed by the sampling circuit, or if the target signal or the target signal changes, an adaptive filtering module adopted by the detection circuit can recalculate the optimal parameter of the adaptive filter, so that an accurate target signal is obtained; thus, the metering error of the electric energy metering equipment is greatly reduced.
In order to better understand the technical solution of the present application, a specific example is described below.
FIG. 6 is a typical current sensing device with current self calibration, R0Is a sampling resistor, and the load current on the live line L is set as IloadFrequency of f0Current I generated by a reference current sourcerefFrequency of f1The reference current source is connected with the live line L in parallel at R0Two ends. ADC module acquisition V1P/V1NThe voltage of (a) can be obtained while including IloadAnd IrefUsing a filter bank to filter the signal to isolate IloadAnd IrefThereby realizing the pair IloadThe measurement of (2). At the same time, the current I generated by the reference signal sourcerefIs constant, so I is obtained from the filter bankrefThe signal size can realize the monitoring of the sampling circuit parameters and self calibration.
In practical application, the ①, ②, ③, ④ and ⑤ wires connect the detection metering module and the sampling module through wires and connecting terminals, and for example, a single-phase electric meter inevitably has vibration during installation and transportation of the electric meter, so that the wires fall off.
Specifically, the method comprises the following steps:
case 1: the self-calibration principle of the detection circuit is that a signal with the frequency f1 is extracted from an output signal of an ADC module to judge whether an external circuit parameter changes, in practical application, f1 is difficult to keep an ideal state fixed, and if the frequency f1 of a reference current source changes or an interference signal exists, the final detection result is affected, and metering errors are caused.
In case 2, if at least one of the conductors ② and ③ is broken, the electric meter cannot live, and the phenomena of serious measurement distortion and more electric charge are caused.
Case 3, if at least one of conductors ① and ④ is broken, the current self-calibration theory is constant based on the reference current source, and once the reference current source is opened, the system can consider that R is the open circuit0Change to a very small value, thereby changing IloadThe calibration is carried out to a large value, and the most intuitive result on the metering of the electric meter is that the electric meter is overcharged, and the loss is caused to a user. In addition, the open circuit of the current source will cause uncontrollable damage to the system.
In case 4, if the ⑤ conductor is broken, the phenomena of excessive effective value and irregular electricity charge also occur.
According to the detection circuit according to the first embodiment of the present application, the current detection device and the problems proposed in the current detection device shown in fig. 6 are improved, and as shown in fig. 7, the detailed configuration is as follows:
for case 1: adding adaptive filtering module
The detection circuit is additionally provided with an adaptive filtering module which comprises an adaptive filter and a subtracter, wherein the adaptive filter is an FIR transverse filter, and each order parameter of the adaptive filter is calculated and fixed before being used;
the specific calculation and fixing method comprises the following steps: an adaptive filtering module (comprising a subtracter and an adaptive filter) and a sampling circuit R0And a reference current source IrefAfter connection, close IrefAnd only an alternating signal (including I)load) The alternating current signal passes through the adaptive filter to enable the output of the adder to be zero, then according to an iterative formula of each order of parameters, the mean square expected value of the output of the adder tends to be minimum through multiple iterations to obtain the maximum parameters, and then each order of parameters of the filter are fixed.
An adaptive filtering module (comprising a subtracter and an adaptive filter) with fixed parameters of each order and a sampling circuit R0And a reference current source IrefAfter connection, the reference current source I is switched onrefAnd only an alternating signal (including I)refAnd Iload) The AC signal is respectively input into the input end of the adaptive filter with fixed parameters and the first input end of the subtracter, and the adaptive filter with fixed parameters filters (i.e. filters I) the AC signalref) Inputting the obtained alternating current signal to a second input end of a subtracter, and outputting to obtain a reference current source I by subtracting the alternating current signal of the first input end and the alternating current signal of the second input end by the subtracterrefOf the signal of (1).
Because the self-adaptive filtering module physically separates the reference current source by filtering other signals, the frequency of the reference current source before and after separation cannot be responded, and the change of the frequency of the reference current source cannot cause metering error;
if an interference signal is present, the adaptive filtering module may recalculate the fixed parameters of the adaptive filter so that the interference signal is within the filtering range of the adaptive filter, and thus the frequency f1 of the reference current source is not affected.
For case 2: adding detection and protection measures for dropping sampling line
As shown in FIG. 7, R is added on the basis of FIG. 63And a first detection module for detecting signals of the V1P/V1N pins to determine whether the conductors of the sampling lines ② and ③ are disconnected, and simultaneously, a 1K resistor R is connected between the sampling lines ② and ③3When the working condition of the sampling line is dropped, the 1K jumper resistor can pull the differential mode signal V of the sampling line1P-V1NThereby preventing voltage creeping caused by dropping the sampling line.
For case 3: method for increasing reference current source disconnection detection and protection measures
In FIG. 7, R is added to that in FIG. 64And a second detection module. Taking a 5V metering system as an example, under a normal working condition, the IAMS port voltage V of the reference current source1Substantially equal to 0V, V being substantially equal to 0V when the reference current source is tripped (at least one of ① or ④ being open)1Will become high level of about 5V, and the detection module at the momentThe wire breaking working condition is sent to the signal processing module; meanwhile, once the second detection module monitors the disconnection condition of the reference current source, the resistor R4The follow current loop is provided when the reference current source has an open circuit fault, so that the charging fault of the ammeter or the system breakdown is avoided.
For case 4: adds the measures of detecting and protecting the falling live wire
As shown in fig. 7, a first detection module is added on the basis of the figure, and the first detection module is used for detecting V1P/V1NWhether the signals of the pins have abnormal alternating current signals or not; at the same time, to prevent the cause of V1P/V1NThe first detection module further comprises a detection algorithm module for reliably detecting V by relating to the detection algorithm1P/V1NAnd judging whether the fire wire is actually disconnected or not by the abnormal alternating current signal, and feeding back to the signal processing module.
Meanwhile, when No. ⑤ is disconnected, V of the detection module is measured1P/V1NConnected to the live line L and forming a loop with the system GND, the loop between the neutral line N to the live line L is therefore: zero line N->System GND->Measurement detection module>V1P/V1N—>Manganin signal line 2/3->The voltage difference between the N-L and the L of the live line is periodically passed through V1P/V1NESD protection diode to AVCC (input voltage supplied by power supply module) is turned on to form V1P/V1NAnd the clamping alternating voltage of the system GND is protected.
Further, as shown in fig. 7, an RC filter is added to the circuit of fig. 6, and the RC filter is composed of a resistor R1Capacitor C1A resistor R2And a capacitor C2The differential structure is adopted, so that common-mode interference in signals can be effectively inhibited, and the metering accuracy of the detection circuit is improved.
It is noted that, in the present patent application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the use of the verb "comprise a" to define an element does not exclude the presence of another, same element in a process, method, article, or apparatus that comprises the element. In the present patent application, if it is mentioned that a certain action is executed according to a certain element, it means that the action is executed according to at least the element, and two cases are included: performing the action based only on the element, and performing the action based on the element and other elements. The expression of a plurality of, a plurality of and the like includes 2, 2 and more than 2, more than 2 and more than 2.
All documents mentioned in this application are to be considered as being incorporated in their entirety into the disclosure of this application so as to be subject to modification as necessary. Further, it is understood that various changes or modifications may be made to the present application by those skilled in the art after reading the above disclosure of the present application, and such equivalents are also within the scope of the present application as claimed.
Claims (10)
1. A detection circuit, comprising:
a reference current source for outputting a second frequency alternating current signal;
a sampling circuit coupled to the reference current source, the sampling circuit further coupled to a first signal source that outputs a first frequency ac signal, the sampling circuit outputting a sampling signal of a mixed signal of the first frequency ac signal and the second frequency ac signal;
the adaptive filtering module comprises an adaptive filter and a subtracter, wherein the sampling circuit is respectively coupled to an input end of the adaptive filter and a first input end of the subtracter, an output end of the adaptive filter is coupled to a second input end of the subtracter, the adaptive filter is used for filtering the sampling signal to obtain the first frequency alternating current signal, and the subtracter is used for subtracting the sampling signal of the first input end and the first frequency alternating current signal of the second input end and then outputting the second frequency alternating current signal;
and the signal processing module is coupled with the self-adaptive filtering module and is used for carrying out signal processing on the second frequency alternating current signal output by the self-adaptive filtering module.
2. The detection circuit of claim 1, wherein the adaptive filter requires calculation and fixing of each order parameter of the adaptive filter before use, and the each order parameter is determined based on a steepest descent method.
3. The detection circuit of claim 2, wherein the parameters of each order are determined based on a least mean square method, and the parameters of each order of the adaptive filter are obtained by minimizing an expected mean square value of the output of the adder through a plurality of iterations according to an iteration formula of the parameters of each order of the FIR filter.
4. The detection circuit of claim 1, further comprising an analog-to-digital converter coupled to the sampling circuit, the analog-to-digital converter coupled to an input of the adaptive filtering module.
5. The detection circuit of claim 4, further comprising a first detection module coupled to two inputs of the analog-to-digital converter, the first detection module being coupled to the signal processing module, the first detector being configured to detect whether an abnormal AC signal is present in the signals at the first input and the second input of the analog-to-digital converter.
6. The detection circuit of claim 5, further comprising:
an RC filter having an input coupled to the sampling circuit, an output of the RC filter being coupled to an input of the analog-to-digital converter;
a first impedance element coupled across the sampling circuit.
7. The detection circuit of claim 6, further comprising:
the input end of the second detection module is coupled with the reference current source, and the output end of the second detection module is coupled with the signal processing module and used for detecting whether the reference current source has an open-circuit fault or not and feeding back the open-circuit fault to the signal processing module;
a second impedance element having one end coupled to the reference current source and another end coupled to ground.
8. The detection circuit of claim 7, wherein the sampling circuit samples using a manganin or current transformer.
9. An electric energy metering chip, characterized in that it comprises a detection circuit according to any one of claims 1 to 8.
10. An electric energy metering device, characterized in that it comprises the electric energy metering chip of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811398987.1A CN111208328A (en) | 2018-11-22 | 2018-11-22 | Detection circuit and electric energy metering chip and equipment based on detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811398987.1A CN111208328A (en) | 2018-11-22 | 2018-11-22 | Detection circuit and electric energy metering chip and equipment based on detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111208328A true CN111208328A (en) | 2020-05-29 |
Family
ID=70786615
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811398987.1A Pending CN111208328A (en) | 2018-11-22 | 2018-11-22 | Detection circuit and electric energy metering chip and equipment based on detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111208328A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113376509A (en) * | 2021-06-09 | 2021-09-10 | 深圳麦歌恩科技有限公司 | Chip self-checking circuit, chip and self-checking method |
-
2018
- 2018-11-22 CN CN201811398987.1A patent/CN111208328A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113376509A (en) * | 2021-06-09 | 2021-09-10 | 深圳麦歌恩科技有限公司 | Chip self-checking circuit, chip and self-checking method |
| CN113376509B (en) * | 2021-06-09 | 2022-10-18 | 深圳麦歌恩科技有限公司 | Chip self-checking circuit, chip and self-checking method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107102236B (en) | A kind of fault line selection method for single-phase-to-ground fault based on waveform correlation analysis after failure | |
| WO2015139587A1 (en) | Method for detecting ground fault of distribution network area and system for positioning ground fault area of distribution network | |
| CN107091969B (en) | Intelligent detection device and method for direct current looped network | |
| RU2583452C2 (en) | Directed detection of resistive ground fault and rupture of conductor of medium voltage | |
| CN105548719A (en) | Detection circuit and method of grounding insulation resistors | |
| CN111505405A (en) | On-line power measurement | |
| CN103728481A (en) | Method and device for detecting metal oxide arrester resistive current | |
| CN106707030B (en) | Method and device for measuring ground impedance and power loss of distribution transformer | |
| CN111095000A (en) | High fidelity voltage measurement using capacitively coupled voltage transformers | |
| CN105823954B (en) | Detection device and method for grounding point of storage battery pack and direct-current power supply system | |
| CN109142993A (en) | A kind of multifunction insulating detector suitable for DC power system | |
| CN102495328B (en) | Differential power reactor fault on-line monitoring instrument | |
| CN109375120A (en) | The monitoring method of alternating current is scurried into DC power system | |
| CN207817128U (en) | A kind of looped network of DC power intelligent detection device | |
| CN105717426A (en) | Insulation monitoring device and method capable of preventing buses from misoperation | |
| CN111208328A (en) | Detection circuit and electric energy metering chip and equipment based on detection circuit | |
| Nordman et al. | A wireless sensor concept for managing electrical distribution networks | |
| CN112083299B (en) | DC system insulation fault prediction method based on Kalman filtering | |
| CN209387708U (en) | A kind of detection circuit and electric energy computation chip and equipment based on this circuit | |
| CN111654109B (en) | Automatic parameter correction method for intelligent low-voltage shunt monitoring unit | |
| CN105403808B (en) | A kind of localization method and device of DC line earth fault | |
| CN213091801U (en) | Insulation monitoring device and track-assisted inverter system | |
| CN212379482U (en) | One-point-to-ground insulation fault H bridge monitoring device for direct current system of transformer substation | |
| CN105203886A (en) | Capacitive type current transformer online detection device and method | |
| CN104391145A (en) | Online low voltage detection device for electric leakage and electric energy steal and implement method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |