CN111007313A - Electricity stealing identification circuit and method and electricity meter - Google Patents
Electricity stealing identification circuit and method and electricity meter Download PDFInfo
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Abstract
The invention discloses an electricity stealing identification circuit and method and an electricity meter. The electricity stealing identification circuit comprises a mutual inductance rectification power supply circuit, a voltage sampling circuit and a microcontroller; the mutual inductance rectification power supply circuit is connected with the microcontroller after penetrating through a live wire and a zero line respectively, converts commercial power into direct current and supplies power to the microcontroller; the voltage sampling circuit is respectively connected with the zero line and the microcontroller, collects voltage and sends a voltage signal to the microcontroller; and the microcontroller calculates the effective value of the voltage according to the voltage signal, obtains the converted voltage value according to the effective value and the voltage scaling factor, and judges that electricity stealing behavior exists when the voltage value is smaller than a preset value. The mutual inductance rectification power supply circuit forms a supplementary power supply through the live wire and the zero wire, so that the electric meter can continuously run when the live wire or the zero wire is separated from the connection of the electric meter, the problem that the maintenance cost is too high due to the fact that the battery needs to be replaced when the battery is used as the supplementary power supply is solved, and great convenience is brought to recognition of electricity stealing behaviors and calculation of electricity stealing amount.
Description
Technical Field
The invention relates to the technical field of electricity stealing prevention, in particular to an electricity stealing identification circuit, an electricity stealing identification method and an electricity meter.
Background
At present, most of electric meters used by domestic and foreign users are electronic electric energy meters, and the general types of the electronic electric meters are as follows: the electric energy meters of the types are all provided with an alternating current power supply by an external power supply line, then the alternating current power supply is converted into direct current by a power supply conversion module inside the electric energy meter, and the direct current is supplied to an MCU system inside the electric energy meter, so that the electric quantity metering function required by the electric energy meter is completed. The system operation of ammeter does not leave the supply of external power source, consequently steals the electric action and takes place, when breaking away from the ammeter line with arbitrary inlet wire (live wire or zero line) in the power supply passively, the ammeter can be because of there is not the unable operation of external power supply, causes the user to steal the power consumption under the electric environment, and the ammeter does not measure the electric quantity, brings the power consumption loss for electric power company.
To solve this problem, there is currently a scheme that: when no external alternating current power supply supplies power, the battery supplies power to enable the electric meter system to run, and the electric meter meters the power consumption. Because the battery capacity is limited, the time for supporting the operation of the electricity meter is limited, if the battery is replaced, the battery is very troublesome, if the rechargeable battery is adopted, defects exist, if a power thief does not periodically recover the power supply, the rechargeable battery cannot be charged, and the situation that the battery does not have power also occurs, so the battery power supply scheme is not the optimal scheme.
Disclosure of Invention
The invention mainly aims to provide an electricity stealing identification circuit, an electricity stealing identification method and an electricity meter, and aims to solve the technical problem that a scheme that the electricity meter uses a battery for power supply is not ideal in the prior art.
To achieve the above object, the present invention provides an electricity stealing identification circuit, comprising:
the mutual inductance rectification power supply circuit, the voltage sampling circuit and the microcontroller are connected; wherein the content of the first and second substances,
the mutual inductance rectification power supply circuit is connected with the microcontroller after penetrating through a live wire and a zero line respectively, and is used for converting commercial power into direct current and supplying power to the microcontroller;
the voltage sampling circuit is respectively connected with the zero line and the microcontroller, and is used for collecting voltage and sending a voltage signal to the microcontroller;
and the microcontroller is used for calculating the effective value of the voltage according to the voltage signal, obtaining the converted voltage value according to the effective value of the voltage and the voltage scaling factor, and judging that electricity stealing behavior exists when the converted voltage value is smaller than a preset value.
Preferably, the mutual inductance rectification power supply circuit comprises a mutual inductance unit, a rectification power supply unit and a DC-DC unit; the mutual inductance unit is connected with the rectification power supply unit after penetrating through the live wire and the zero line respectively; the rectification power supply unit is connected with the DC-DC unit; the DC-DC unit is connected with the microcontroller.
Preferably, the mutual inductance unit comprises a first mutual inductor and a second mutual inductor, the first mutual inductor is respectively connected with the zero line and the rectification power supply unit, and the second mutual inductor is respectively connected with the live line and the rectification power supply unit.
Preferably, the rectifying power supply unit includes a first rectifying bridge, a second rectifying bridge, a first resistor, a second resistor, a voltage regulator diode, a first capacitor, and a second capacitor; wherein the content of the first and second substances,
two input ends of the first rectifier bridge are connected with the first mutual inductor, a positive output end of the first rectifier bridge is connected with a first end of the first resistor, and a negative output end of the first rectifier bridge is grounded;
two input ends of the second rectifier bridge are connected with the second mutual inductor, a positive output end of the second rectifier bridge is connected with a first end of the second resistor, and a negative output end of the second rectifier bridge is grounded;
the voltage stabilizing diode, the first capacitor and the second capacitor are connected in parallel, the cathode of the voltage stabilizing diode is respectively connected with the second end of the first resistor, the second end of the second resistor and the DC-DC unit, and the anode of the voltage stabilizing diode is grounded.
Preferably, the DC-DC unit includes a first diode, a second diode, a third capacitor, a third resistor, a voltage reduction chip, a battery, and a transfer point; wherein the content of the first and second substances,
the anode of the first diode is connected with the cathode of the voltage stabilizing diode, and the cathode of the first diode is respectively connected with the cathode of the second diode and the input end of the voltage reduction chip;
the anode of the second diode is connected with the anode of the battery through the third resistor and the switching point in sequence;
the output end of the voltage reduction chip is respectively connected with the microcontroller and the first end of the third capacitor;
and the negative electrode of the battery and the second end of the third capacitor are both grounded.
Preferably, the voltage sampling circuit comprises a fourth resistor, a fifth resistor and a fourth capacitor; wherein the content of the first and second substances,
the fourth resistor is formed by connecting six resistors in series, and the first end of the fourth resistor is connected with the zero line;
the fifth resistor is connected in parallel with the fourth capacitor, the first end of the fourth capacitor is connected with the second end of the fourth resistor and the microcontroller respectively, and the second end of the fourth capacitor is grounded.
The invention also provides an electricity stealing identification method, which comprises the following steps:
the mutual inductance rectification power supply circuit penetrating through the live wire and the zero line converts commercial power into direct current and supplies power to the microcontroller;
collecting voltage through a voltage sampling circuit, and sending a voltage signal to a microcontroller;
and calculating the effective value of the voltage according to the voltage signal through a microcontroller, obtaining a converted voltage value according to the effective value of the voltage and the voltage scaling factor, and judging that electricity stealing behavior exists when the converted voltage value is smaller than a preset value.
Preferably, the effective value of the voltage is calculated from the voltage signal by:
Value_u＝V×G×K；
wherein Value _ u is an effective Value of voltage, V is a voltage signal, G is a preset voltage gain, K is a constant, and K is 1.8117 × 109。
Preferably, after the step of determining that there is electricity stealing activity, the method further comprises:
collecting current through a current sampling circuit, and sending a current signal to the microcontroller;
calculating the effective value of the current according to the current signal through a microcontroller, and obtaining a converted current value according to the effective value of the current and the current scaling factor;
and calculating the electricity stealing capacity according to the converted voltage value and the converted current value.
The invention also provides an electricity stealing identification electric meter which comprises the electricity stealing identification circuit or applies the electricity stealing identification method.
The mutual inductance rectification power supply circuit, the voltage sampling circuit and the microcontroller are arranged in the electricity stealing identification circuit; the mutual inductance rectification power supply circuit is connected with the microcontroller after penetrating through a live wire and a zero line respectively, and is used for converting commercial power into direct current and supplying power to the microcontroller; the voltage sampling circuit is respectively connected with the zero line and the microcontroller and is used for collecting voltage and sending a voltage signal to the microcontroller; the microcontroller is used for converting the voltage signal to obtain a converted voltage value, and when the converted voltage value is smaller than a preset value, the existence of electricity stealing behavior is judged. The mutual inductance rectification power supply circuit forms a supplementary power supply through the live wire and the zero wire, so that the electric meter can continuously run when the live wire or the zero wire is separated from the electric meter connection, the problem that the maintenance cost is too high due to the fact that the battery needs to be replaced when the battery serves as the supplementary power supply is avoided, and great convenience is brought to recognition of electricity stealing behaviors and calculation of electricity stealing electric quantity.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a functional block diagram of an embodiment of a theft identification circuit of the present invention;
FIG. 2 is a schematic diagram of an alternative configuration of the tamper identification circuit of FIG. 1;
fig. 3 is a flow chart of an embodiment of the electricity stealing identification method of the invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) | |
| 100 | Mutual inductance rectification power supply circuit | U1～U3 | First to |
|
| 200 | Voltage sampling circuit | R1～R5 | First to |
|
| 300 | Current sampling circuit | D1～D2 | First to |
|
| 400 | Power management circuit | C1～C4 | First to |
|
| 110 | Mutual induction unit | ZD | |
|
| 120 | Rectifying power supply unit | | Transformer device | |
| 130 | DC-DC unit | RV | Voltage |
|
| 310 | Manganese copper sampling unit | RT | |
|
| 320 | CT sampling unit | P | Transfer point | |
| MCU | Micro-controller | B | Battery with a battery cell | |
| IC | Step-down chip |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides an electricity stealing identification circuit.
Referring to fig. 1, in an embodiment, the electricity stealing identification circuit includes a mutual inductance rectification power supply circuit 100, a voltage sampling circuit 200 and a microcontroller MCU; the mutual inductance rectification power supply circuit 100 is respectively connected with the microcontroller MCU after penetrating through a live wire L and a zero wire N, and is used for converting commercial power into direct current and supplying power to the microcontroller MCU; the voltage sampling circuit 200 is respectively connected with the zero line N and the microcontroller MCU, and is used for collecting voltage and sending a voltage signal to the microcontroller MCU; and the microcontroller MCU is used for calculating an effective value of voltage according to the voltage signal, obtaining a converted voltage value according to the effective value of voltage and the voltage scaling factor, and judging that electricity stealing behavior exists when the converted voltage value is smaller than a preset value.
It should be noted that, in order to prevent the electricity meter from being unable to operate due to no external power supply when the incoming line (live line or zero line) in the power supply is disconnected from the connection line of the electricity meter, the user uses electricity in an electricity stealing environment and the electricity meter does not measure the electric quantity, in the prior art, a battery is usually used as a supplementary power supply of the electricity meter, and the electricity meter is powered when the power supply is powered off. This embodiment is through increasing mutual inductance rectification power supply circuit 100, gets the electricity from live wire L or zero line N to convert the commercial power to the direct current and supply power for microcontroller MCU, need frequently change the problem of battery when having solved the use battery as supplementary power.
It can be understood that, after the microcontroller MCU obtains the converted voltage value, if the voltage value is 0 (or is defined as lower than 30V, or lower than 50% of the normal voltage value, which can be defined according to practical situations), it can be determined that the power consumption is in a power stealing mode (i.e. the live wire or the neutral wire is disconnected), and the power consumption can be separately put into the register of the management table for recording, and if the voltage value is smaller than the preset value, it is determined that the power consumption is normal.
In a specific implementation, the effective value of the voltage calculated by the microcontroller MCU according to the voltage signal may be represented by the following formula 1:
value _ u ═ V × G × K; ....... (formula 1)
Wherein: v is a voltage signal, G is a preset voltage gain, K is a constant, and K is 1.8117 multiplied by 109。
Taking the sampling voltage signal of the voltage channel as 18mV and the gain as 1 as an example, the value of the voltage valid value register should be: value _ u is 0.018 × 1 × 1.8117 × 109＝0x1F19927
Before obtaining the converted voltage value according to the effective value and the voltage scaling factor, the voltage scaling factor needs to be determined, and the voltage scaling factor can be determined by the following method: and calibrating the effective value U0 of the collected voltage to a standard voltage Un, and obtaining D (D is a voltage scaling factor and is a fixed coefficient) according to a formula U0 multiplied by D-Un.
Specifically, the standard voltage Un is set to 220.00V, and 2-bit decimal is retained for calculation, taking the effective value of the voltage 0x1F19927 as an example, and 0x1F19927 × D22000, that is, 32610599 × D22000, to finally obtain the voltage scaling factor D6.746 × 10-4
The converted voltage value is obtained according to the effective value of the voltage and the voltage scaling factor, that is, the converted voltage value is calculated by adopting the following formula 2:
vx is Value _ u × D; ..
Where Vx is the converted voltage Value, Value _ u is the effective Value of the voltage shown in the voltage register, and D is the voltage scaling factor.
Further, the electricity stealing identification circuit further comprises a current sampling circuit 300, the input end of the current sampling circuit 300 is connected with the live wire L and penetrates through the zero line N, and the output end of the current sampling circuit 300 is connected with the microcontroller MCU.
It should be understood that, after sampling the current, the microcontroller MCU may obtain the converted current value in the same processing manner as the voltage signal, and may calculate the electric quantity running under the electricity stealing behavior according to the converted current value and the converted voltage value, thereby avoiding the problem that the electric quantity of electricity stealing cannot be measured.
It should be noted that, the processing of the current signal by the microcontroller MCU may be performed in the same manner as the voltage signal processing, taking the sampled current signal of the current channel as 2.35mV and the gain as 16 as an example, the value of the current effective value register should be: value _ i is 0.00235 × 16 × 1.8117 × 109After obtaining the effective value of the current, the converted current value may be obtained by the same method, which is not described herein again. According to the conversionThe power can be calculated by the current value and the voltage value after conversion, and the electric quantity can be obtained by multiplying the power by the time. Therefore, the electricity consumption of the electricity meter in the electricity stealing state can be calculated through the method.
Of course, the power calculation method may also adopt other manners, such as calculating the power value by using the following formula 3:
value _ p is Vi × Gi × Vv × Gv × K × cos θ; ....... (formula 1)
Where Vi is a current signal, Vv is a voltage signal, Gi is a preset current gain, Gv is a preset voltage gain, K is a constant, K is 1.5413 × 109And cos θ is the power factor.
Taking the example when Vv is 18mV, Gv is 1, Vi is 2.3mV, Gi is 16, cos θ is 1, for active metering, the value of the power register should be: value _ p is 0.0023 × 0.018 × 1 × 16 × 1.5413 × 109×1＝0xF941D。
Further, the electricity stealing identification circuit further comprises a power management circuit 400, wherein the power management circuit 400 is connected with the mutual inductance rectification power supply circuit 100 and is used for supplying power to the microcontroller MCU when no electricity stealing behavior is identified.
It should be noted that, when the microcontroller MCU determines that there is no electricity stealing behavior, it may switch to the power management circuit 400 to supply power to the microcontroller MCU, and the microcontroller MCU enters a normal operating state, and stores the power consumption in the normal power management table register for standby.
In the embodiment, the mutual inductance rectification power supply circuit, the voltage sampling circuit and the microcontroller are arranged in the electricity stealing identification circuit; the mutual inductance rectification power supply circuit is connected with the microcontroller after penetrating through a live wire and a zero line respectively, and is used for converting commercial power into direct current and supplying power to the microcontroller; the voltage sampling circuit is respectively connected with the zero line and the microcontroller and is used for collecting voltage and sending a voltage signal to the microcontroller; the microcontroller is used for converting the voltage signal to obtain a converted voltage value, and when the converted voltage value is smaller than a preset value, the existence of electricity stealing behavior is judged. The mutual inductance rectification power supply circuit forms a supplementary power supply through the live wire and the zero wire, so that the electric meter can continuously run when the live wire or the zero wire is separated from the electric meter connection, the problem that the maintenance cost is too high due to the fact that the battery needs to be replaced when the battery serves as the supplementary power supply is avoided, and great convenience is brought to recognition of electricity stealing behaviors and calculation of electricity stealing electric quantity.
Referring to fig. 2, fig. 2 is a schematic diagram of an alternative structure of the electric larceny identification circuit of fig. 1.
In this embodiment, the mutual inductance rectification power supply circuit 100 includes a mutual inductance unit 110, a rectification power supply unit 120, and a DC-DC unit 130; the mutual inductance unit 110 is connected with the rectification power supply unit 120 after penetrating through the live line L and the zero line N respectively; the rectifying power supply unit 120 is connected to the DC-DC unit 130; the DC-DC unit 130 is connected to the microcontroller MCU.
Further, the mutual inductance unit 110 includes a first mutual inductor (not marked) and a second mutual inductor (not marked), the first mutual inductor is respectively connected with the zero line N and the rectification power supply unit 120, and the second mutual inductor is respectively connected with the live line L and the rectification power supply unit 120.
It should be noted that, in the electricity utilization process, the electricity stealing user may disconnect the zero line N or the live line L, in order to ensure the uninterrupted power supply, the embodiment is provided with two transformers, which are respectively matched with the rectification power supply unit 120 and the DC-DC unit 130 through the live line L and the zero line N to form a transformer power supply module, and a power supply generated by the transformer by using the electromagnetic principle is incorporated into the power supply of the electric meter MCU system to serve as a supplementary power source for the MCU to operate.
Further, the rectifying power supply unit 100 includes a first rectifying bridge U1, a second rectifying bridge U2, a first resistor R1, a second resistor R2, a zener diode ZD, a first capacitor C1 and a second capacitor C2; two input ends of the first rectifier bridge U1 are connected with the first transformer, a positive output end of the first rectifier bridge U1 is connected with a first end of the first resistor R1, and a negative output end of the first rectifier bridge U1 is grounded; two input ends of the second rectifier bridge U2 are connected with the second transformer, a positive output end of the second rectifier bridge U2 is connected with a first end of the second resistor R2, and a negative output end of the second rectifier bridge U2 is grounded; the zener diode ZD, the first capacitor C1 and the second capacitor C2 are connected in parallel, a cathode of the zener diode ZD is connected to the second end of the first resistor R1, the second end of the second resistor R2 and the DC-DC unit 130, respectively, and an anode of the zener diode ZD is grounded.
It can be understood that a rectifier bridge and a resistor are connected behind each mutual inductor, so that alternating voltage generated by each mutual inductor can be effectively rectified, and short circuit is prevented; the first capacitor C1 and the second capacitor C2 are both filter capacitors, and are used for filtering the signal output to the DC-DC unit 130 to form a stable direct current.
It should be noted that the rectifying power supply unit 120 rectifies the 220V voltage to obtain a voltage of about 12V, and then steps down the voltage by the DC-DC unit 130 to obtain a power supply voltage of about 3.3V for the microcontroller MCU.
Further, the DC-DC unit 130 includes a first diode D1, a second diode D2, a third capacitor C3, a third resistor R3, a buck chip IC, a battery B, and a transfer point P; wherein, the anode of the first diode D1 is connected to the cathode of the zener diode ZD, and the cathode of the first diode D1 is connected to the cathode of the second diode D2 and the input terminal of the buck chip IC, respectively; the anode of the second diode D2 is connected to the anode of the battery B through the third resistor R3 and the transfer point P in sequence; the output end of the voltage reduction chip IC is respectively connected with the microcontroller MCU and the first end of the third capacitor C3; the negative electrode of the battery B and the second end of the third capacitor C3 are both grounded.
In a specific implementation, the battery B is a power supply source of a clock in a carrying device (such as an electricity meter) of the electricity stealing identification circuit, and in order to prevent the electricity consumption of the battery B during production, a switching point P can be set in the DC-DC circuit 130, and the switching point P is switched on only when the circuit is in use.
Further, the voltage sampling circuit 200 includes a fourth resistor R4, a fifth resistor R5, and a fourth capacitor C4; the fourth resistor R4 is formed by six resistors connected in series, and the first end of the fourth resistor R4 is connected with the zero line N; the fifth resistor R5 is connected in parallel with the fourth capacitor C4, a first end of the fourth capacitor C4 is connected to a second end of the fourth resistor R4 and the microcontroller MCU, respectively, and a second end of the fourth capacitor C4 is grounded.
It should be noted that, a plurality of resistors with small resistance values are connected in series to form a sampling resistor with large resistance value, and the resistors are connected in series to divide voltage, so that the voltage of the zero line can be reduced to the sampling range of the microcontroller MCU, and the sampling precision of the voltage of the zero line can be effectively improved.
Further, the current sampling circuit 300 includes a manganin sampling unit 310 and a CT sampling unit 320; the manganin sampling unit 310 comprises a manganin resistor (not labeled), the manganin resistor is connected with the live wire L, and the manganin sampling unit 310 is used for sampling current of the live wire through the manganin resistor; the CT sampling unit 320 includes a CT coil (not labeled), the CT coil penetrates the zero line N, and the CT sampling unit 320 is configured to sample a zero line current through the CT coil.
It should be understood that the sampling is carried out through the manganin resistor during the sampling of live wire current, and the sampling of alternating current component and direct current component can be carried out simultaneously, and normal measurement is guaranteed, but if the manganin resistor is adopted in two ways of the current channel, the short circuit of a power grid can be caused, so that the CT coil is used for sampling on the zero line channel in the embodiment, and the circuit safety is effectively guaranteed.
Further, the power management circuit 400 includes a third rectifier bridge U3, a transformer T1, a voltage dependent resistor RV, and a thermistor RT; the first end of the piezoresistor RV is connected with the zero line N, and the second end of the piezoresistor RV is connected with the live line L; a first end of the thermistor RT is connected with the zero line N and a first end of the piezoresistor RV respectively, and a second end of the thermistor RT is connected with a first end of a primary coil of the transformer T1; a second end of the primary coil of the transformer T1 is connected to the live line L, and a first end of the secondary coil of the transformer T1 and a second end of the secondary coil of the transformer T1 are respectively connected to two input ends of the third rectifier bridge U3; the positive output end of the third rectifier bridge U3 is connected to the cathode of the zener diode ZD, and the negative output end of the third rectifier bridge U3 is grounded.
It should be noted that, the varistor RV is used to protect a power management circuit, for example, if a general mains supply is 220V voltage input, once the mains supply is unstable and exceeds a voltage specification (for example, 245V), the varistor RV may be turned on immediately to absorb redundant voltage, so as to protect a back-end circuit; the thermistor RT is used for preventing the service life of the capacitor and the rectifier bridge from being shortened due to overlarge current during starting.
According to the embodiment, through the specific design of the mutual inductance rectification power supply circuit and the specific design of the power management circuit, more stable direct current can be obtained to supply power for the electricity larceny prevention circuit, and meanwhile, the reliability of the whole power supply circuit is also improved. In addition, through the specific design of the voltage sampling circuit, a more accurate voltage signal can be obtained, so that the judgment result of the electricity stealing behavior is more accurate.
Referring to fig. 3, fig. 3 is a flow chart illustrating an embodiment of a method for identifying electricity stealing according to the present invention.
In this embodiment, the electricity stealing identification method includes the following steps:
s10: the mutual inductance rectification power supply circuit penetrating through the live wire and the zero line converts commercial power into direct current and supplies power to the microcontroller;
s20: collecting voltage through a voltage sampling circuit, and sending a voltage signal to a microcontroller;
s30: and calculating the effective value of the voltage according to the voltage signal through a microcontroller, obtaining a converted voltage value according to the effective value of the voltage and the voltage scaling factor, and judging that electricity stealing behavior exists when the converted voltage value is smaller than a preset value.
It can be understood that, after the microcontroller MCU obtains the converted voltage value, if the voltage value is 0 (or is defined as lower than 30V, or lower than 50% of the normal voltage value, which can be defined according to practical situations), it can be determined that the power consumption is in a power stealing mode (i.e. the live wire or the neutral wire is disconnected), and the power consumption can be separately put into the register of the management table for recording, and if the voltage value is smaller than the preset value, it is determined that the power consumption is normal.
In a specific implementation, the effective value of the voltage calculated by the microcontroller MCU according to the voltage signal may be represented by the following formula 1:
value _ u ═ V × G × K; ....... (formula 1)
Wherein: v is a voltage signal, G is a preset voltage gain, K is a constant, and K is 1.8117 multiplied by 109。
Taking the sampling voltage signal of the voltage channel as 18mV and the gain as 1 as an example, the value of the voltage valid value register should be: value _ u is 0.018 × 1 × 1.8117 × 109＝0x1F19927
Before obtaining the converted voltage value according to the effective value and the voltage scaling factor, the voltage scaling factor needs to be determined, and the voltage scaling factor can be determined by the following method: and calibrating the effective value U0 of the collected voltage to a standard voltage Un, and obtaining D (D is a voltage scaling factor and is a fixed coefficient) according to a formula U0 multiplied by D-Un.
Specifically, the standard voltage Un is set to 220.00V, and 2-bit decimal is retained for calculation, taking the effective value of the voltage 0x1F19927 as an example, and 0x1F19927 × D22000, that is, 32610599 × D22000, to finally obtain the voltage scaling factor D6.746 × 10-4
The converted voltage value is obtained according to the effective value of the voltage and the voltage scaling factor, that is, the converted voltage value is calculated by adopting the following formula 2:
vx is Value _ u × D; ..
Where Vx is the converted voltage Value, Value _ u is the effective Value of the voltage shown in the voltage register, and D is the voltage scaling factor.
Further, after the step of determining that there is electricity stealing activity, the method further comprises: collecting current through a current sampling circuit, and sending a current signal to the microcontroller; calculating the effective value of the current according to the current signal through a microcontroller, and obtaining a converted current value according to the effective value of the current and the current scaling factor; and calculating the electricity stealing capacity according to the converted voltage value and the converted current value.
It should be noted that the processing of the current signal by the microcontroller MCU may be performed in the same manner as the voltage signal processing, so as to adopt the current channelThe sample current signal is 2.35mV, the gain is 16 for example, and the value of the current effective value register should be: value _ i is 0.00235 × 16 × 1.8117 × 109After obtaining the effective value of the current, the converted current value may be obtained by the same method, which is not described herein again. The power can be calculated according to the converted current value and the converted voltage value, and the electric quantity can be obtained by multiplying the power by the time. Therefore, the electricity consumption of the electricity meter in the electricity stealing state can be calculated through the method.
Of course, the power calculation method may also adopt other manners, such as calculating the power value by using the following formula 3:
value _ p is Vi × Gi × Vv × Gv × K × cos θ; ....... (formula 1)
Where Vi is a current signal, Vv is a voltage signal, Gi is a preset current gain, Gv is a preset voltage gain, K is a constant, K is 1.5413 × 109And cos θ is the power factor.
Taking the example when Vv is 18mV, Gv is 1, Vi is 2.3mV, Gi is 16, cos θ is 1, for active metering, the value of the power register should be: value _ p is 0.0023 × 0.018 × 1 × 16 × 1.5413 × 109×1＝0xF941D。
In the embodiment, commercial power is converted into direct current through the mutual inductance rectification power supply circuit and is supplied to the microcontroller; collecting voltage through a voltage sampling circuit, and sending a voltage signal to a microcontroller; and calculating the effective value of the voltage according to the voltage signal through a microcontroller, obtaining a converted voltage value according to the effective value of the voltage and the voltage scaling factor, and judging that electricity stealing behavior exists when the converted voltage value is smaller than a preset value. Wherein, microcontroller can judge automatically whether there is the electricity consumption of stealing the action, need not artificial intervention to can take notes the power consumption electric quantity, avoid the unable measurement problem of electric quantity of stealing the electricity.
The invention also provides an electricity stealing identification ammeter which comprises the electricity stealing identification circuit or the electricity stealing identification method, and the circuit structure of the electricity stealing identification circuit of the electricity stealing identification ammeter can refer to the embodiment and is not repeated herein; it can be understood that, since the electricity stealing identification electric meter of the embodiment adopts the technical scheme of the electricity stealing identification circuit or the electricity stealing identification method, the electricity stealing identification electric meter has all the beneficial effects.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. The electricity stealing identification circuit is characterized by comprising a mutual inductance rectification power supply circuit, a voltage sampling circuit and a microcontroller; wherein the content of the first and second substances,
the mutual inductance rectification power supply circuit is connected with the microcontroller after penetrating through a live wire and a zero line respectively, and is used for converting commercial power into direct current and supplying power to the microcontroller;
the voltage sampling circuit is respectively connected with the zero line and the microcontroller, and is used for collecting voltage and sending a voltage signal to the microcontroller;
and the microcontroller is used for calculating the effective value of the voltage according to the voltage signal, obtaining the converted voltage value according to the effective value of the voltage and the voltage scaling factor, and judging that electricity stealing behavior exists when the converted voltage value is smaller than a preset value.
2. The electricity stealing identification circuit of claim 1, wherein said mutual inductance rectified power supply circuit comprises a mutual inductance unit, a rectified power supply unit, and a DC-DC unit; the mutual inductance unit is connected with the rectification power supply unit after penetrating through the live wire and the zero line respectively; the rectification power supply unit is connected with the DC-DC unit; the DC-DC unit is connected with the microcontroller.
3. The electricity stealing identification circuit according to claim 2, wherein said mutual inductance unit comprises a first mutual inductor and a second mutual inductor, said first mutual inductor being connected to a neutral line and said rectifying power supply unit, respectively, and said second mutual inductor being connected to a live line and said rectifying power supply unit, respectively.
4. The electricity stealing identification circuit according to claim 3, wherein said rectified power supply unit comprises a first rectifying bridge, a second rectifying bridge, a first resistor, a second resistor, a zener diode, a first capacitor and a second capacitor; wherein the content of the first and second substances,
two input ends of the first rectifier bridge are connected with the first mutual inductor, a positive output end of the first rectifier bridge is connected with a first end of the first resistor, and a negative output end of the first rectifier bridge is grounded;
two input ends of the second rectifier bridge are connected with the second mutual inductor, a positive output end of the second rectifier bridge is connected with a first end of the second resistor, and a negative output end of the second rectifier bridge is grounded;
the voltage stabilizing diode, the first capacitor and the second capacitor are connected in parallel, the cathode of the voltage stabilizing diode is respectively connected with the second end of the first resistor, the second end of the second resistor and the DC-DC unit, and the anode of the voltage stabilizing diode is grounded.
5. The electricity stealing identification circuit according to claim 4, wherein said DC-DC unit includes a first diode, a second diode, a third capacitor, a third resistor, a voltage dropping chip, a battery and a transfer point; wherein the content of the first and second substances,
the anode of the first diode is connected with the cathode of the voltage stabilizing diode, and the cathode of the first diode is respectively connected with the cathode of the second diode and the input end of the voltage reduction chip;
the anode of the second diode is connected with the anode of the battery through the third resistor and the switching point in sequence;
the output end of the voltage reduction chip is respectively connected with the microcontroller and the first end of the third capacitor;
and the negative electrode of the battery and the second end of the third capacitor are both grounded.
6. The electricity stealing identification circuit according to any one of claims 1 to 5, wherein said voltage sampling circuit comprises a fourth resistor, a fifth resistor and a fourth capacitor; wherein the content of the first and second substances,
the fourth resistor is formed by connecting six resistors in series, and the first end of the fourth resistor is connected with the zero line;
the fifth resistor is connected in parallel with the fourth capacitor, the first end of the fourth capacitor is connected with the second end of the fourth resistor and the microcontroller respectively, and the second end of the fourth capacitor is grounded.
7. An electricity stealing identification method, characterized by comprising the steps of:
the mutual inductance rectification power supply circuit penetrating through the live wire and the zero line converts commercial power into direct current and supplies power to the microcontroller;
collecting voltage through a voltage sampling circuit, and sending a voltage signal to a microcontroller;
and calculating the effective value of the voltage according to the voltage signal through the microcontroller, obtaining the converted voltage value according to the effective value of the voltage and the voltage scaling factor, and judging that the electricity stealing behavior exists when the converted voltage value is smaller than a preset value.
8. The electricity theft identification method according to claim 7, wherein the effective value of the voltage is calculated from the voltage signal by:
Value_u＝V×G×K；
wherein Value _ u is an effective Value of voltage, V is a voltage signal, G is a preset voltage gain, K is a constant, and K is 1.8117 × 109。
9. The electricity theft identification method according to claim 8, wherein after the step of determining the existence of an electricity theft action, the method further comprises:
collecting current through a current sampling circuit, and sending a current signal to the microcontroller;
calculating the effective value of the current according to the current signal through a microcontroller, and obtaining a converted current value according to the effective value of the current and the current scaling factor;
and calculating the electricity stealing capacity according to the converted voltage value and the converted current value.
10. An electricity stealing identification electricity meter comprising an electricity stealing identification circuit according to any one of claims 1 to 6 or using an electricity stealing identification method according to any one of claims 7 to 9.
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| CN201911145037.2A CN111007313A (en) | 2019-11-20 | 2019-11-20 | Electricity stealing identification circuit and method and electricity meter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111983276A (en) * | 2020-07-01 | 2020-11-24 | 宁波三星医疗电气股份有限公司 | Electricity stealing prevention method for double-loop electric energy meter |
| CN111999554A (en) * | 2020-08-25 | 2020-11-27 | 成都长城开发科技有限公司 | Zero line detection circuit, ammeter and zero line detection method |
| CN112067891A (en) * | 2020-09-02 | 2020-12-11 | 成都长城开发科技有限公司 | Electric quantity metering circuit and ammeter |
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2019
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111983276A (en) * | 2020-07-01 | 2020-11-24 | 宁波三星医疗电气股份有限公司 | Electricity stealing prevention method for double-loop electric energy meter |
| CN111999554A (en) * | 2020-08-25 | 2020-11-27 | 成都长城开发科技有限公司 | Zero line detection circuit, ammeter and zero line detection method |
| CN112067891A (en) * | 2020-09-02 | 2020-12-11 | 成都长城开发科技有限公司 | Electric quantity metering circuit and ammeter |
| CN112067891B (en) * | 2020-09-02 | 2023-09-08 | 成都长城开发科技股份有限公司 | Electric quantity metering circuit and ammeter |
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