CN218497029U - Voltage detection circuit and system - Google Patents

Abstract

The embodiment of the utility model provides a voltage detection circuit and system relates to the power supply technology field. The voltage detection circuit comprises a first voltage reduction unit, a second voltage reduction unit, a third voltage reduction unit, a rectification unit, a voltage division unit, a voltage stabilization unit, a first relay and a second relay which are arranged in an electric energy meter, wherein the first voltage reduction unit, the second voltage reduction unit, the rectification unit, the third voltage reduction unit and the voltage stabilization unit are sequentially connected in series on a zero line, and the second voltage reduction unit is connected with a load in parallel; the first voltage reduction unit, the second voltage reduction unit and the third voltage reduction unit are all used for reducing the voltage between the zero line and the live line; the rectifying unit is used for rectifying the voltage reduced by the first voltage reducing unit; the voltage division unit is used for dividing the voltage reduced by the third voltage reduction unit; the voltage stabilizing unit is used for stabilizing the voltage divided by the voltage dividing unit and outputting the voltage to the metering unit; the first relay and the second relay are both closed to supply power to the load or both open to disconnect power to the load. Reliable acquisition of voltage is achieved.

Description

Voltage detection circuit and system

Technical Field

The utility model relates to a power supply technical field particularly, relates to a voltage detection circuit and system.

Background

Along with the popularization of intelligent electric energy meters, the demand is increasing day by day, and the demand is different, and the function is various, and under most circumstances, a section of electric energy meter needs multiple functions such as integrated communication, demonstration, measurement, warning, control to need satisfy the special demand in some markets. Different markets and application scenes generate various special requirements, and data display, output terminal detection and power utilization safety are one of the most concerned scenes of various large markets.

The built-in relay of current mainstream electric energy meter draws the switching-on logic simply, only software issue draw the switching-on order can, unable real-time detection judges the various condition of electric energy meter output, because the condition that can't judge the electric energy meter output produces the threat to personal safety easily when the workman is overhauing, traditional solution is to increase voltage detection circuit with the electric energy meter output, voltage detection circuit's output and metering unit are connected, metering unit can judge the certain condition of electric energy meter output through the voltage of gathering the electric energy meter output, but traditional voltage detection circuit is more complicated, the component kind of use is many, the space that PCB occupied is big, whole cost is higher.

SUMMERY OF THE UTILITY MODEL

The utility model aims at including, for example, a voltage detection circuit and system are provided to realize that a circuit is simple and occupy the little voltage detection circuit in PCB space.

The embodiment of the utility model discloses a can realize like this:

in a first aspect, an embodiment of the present invention provides a voltage detection circuit, including a first voltage reduction unit, a second voltage reduction unit, a third voltage reduction unit, a rectification unit, a voltage division unit, a voltage stabilization unit, a first relay and a second relay, which are arranged in an electric energy meter, wherein the first voltage reduction unit, the second voltage reduction unit, the rectification unit, the third voltage reduction unit and the voltage stabilization unit are sequentially connected in series on a zero line, and the second voltage reduction unit is connected in parallel with a load;

the first voltage reduction unit, the second voltage reduction unit and the third voltage reduction unit are all used for reducing the voltage between the zero line and the live line;

the rectifying unit is used for rectifying the voltage reduced by the first voltage reducing unit;

the voltage dividing unit is connected in parallel between the output end of the third voltage reducing unit and the live wire and is used for dividing the voltage reduced by the third voltage reducing unit;

the output end of the voltage stabilizing unit is externally connected with a metering unit, and the voltage stabilizing unit is used for stabilizing the voltage divided by the voltage dividing unit and outputting the voltage to the metering unit for the metering unit to collect;

the first relay is connected with the first voltage reduction unit in parallel, the second relay is connected between the output end of the second voltage reduction unit and the live wire in parallel, and the first relay and the second relay are both closed to supply power to the load or both opened to disconnect the power supply of the load.

In an optional embodiment, the first voltage-reducing unit, the second voltage-reducing unit, and the third voltage-reducing unit each include a plurality of resistors connected in series, and each of the resistors is connected in series to a zero line.

In an optional embodiment, the rectifying unit is a rectifying diode, an anode of the rectifying diode is connected to the output end of the second voltage-reducing unit, and a cathode of the rectifying diode is connected to the input end of the third voltage-reducing unit.

In an alternative embodiment, the voltage regulator unit is a voltage regulator diode, an anode of the voltage regulator diode is connected to the output terminal of the third voltage reduction unit, and a cathode of the voltage regulator diode is connected to the metering unit.

In an optional embodiment, the voltage dividing unit is a voltage dividing resistor, and the voltage dividing resistor is connected in parallel between the output end of the third voltage dropping unit and the live line.

In an optional implementation manner, a communication unit is further disposed in the electric energy meter, the communication unit is connected with the metering unit, and the communication unit is configured to establish communication with the metering unit.

In an optional embodiment, the second voltage reduction unit is further connected in parallel with a switch unit, and the switch unit is connected with the communication unit;

the switch unit is used for establishing communication or breaking communication with the communication unit according to the on or off of the switch.

In an optional embodiment, the voltage detection circuit further comprises a safety unit, wherein the safety unit comprises a safety resistor and a safety capacitor;

the safety regulation unit is used for reducing the voltage between the output end of the voltage stabilizing unit and the live wire and then outputting the voltage to the metering unit.

In a second aspect, an embodiment of the present invention provides a voltage detection system, including an electric energy meter, a metering unit and a voltage detection circuit as in any one of the foregoing embodiments, the voltage detection circuit is disposed in the electric energy meter, the metering unit is disposed outside the electric energy meter and connected to the voltage detection circuit.

In an optional embodiment, the metering unit is an MCU.

The utility model discloses beneficial effect includes, for example:

the embodiment of the utility model provides a pair of voltage detection circuit and system, through first step-down unit, second step-down unit, third step-down unit, the rectifier unit, the voltage divider unit, the steady voltage unit, the design of first relay and second relay, the circuit is whole simple, the device that each unit used is common device, the logic is clear, with low costs and good reliability, the holistic PCB occupation space of circuit is little, be applicable to in the product that PCB layout pressure is big, it is more complicated to have solved traditional voltage detection circuit, the component kind of use is many, the big and higher problem of overall cost of the space that PCB occupied.

Furthermore, the voltage detection circuit can enable the metering unit externally connected with the electric energy meter to collect the voltage of the output end of the metering unit in real time, reliable detection of the voltage is achieved, and then various conditions of the output end of the electric energy meter can be judged by comparing the detected voltage with theoretical voltage values under various conditions calculated by the metering unit subsequently, so that the electricity utilization safety is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is an exemplary block diagram of a voltage detection system according to an embodiment of the present invention;

fig. 2 is an exemplary block diagram of a voltage detection circuit in a voltage detection system according to an embodiment of the present invention;

fig. 3 is a circuit diagram of a voltage detection circuit according to an embodiment of the present invention;

fig. 4 is a second exemplary block diagram of a voltage detection circuit in a voltage detection system according to an embodiment of the present invention;

fig. 5 is a third exemplary block diagram of a voltage detection circuit in a voltage detection system according to an embodiment of the present invention.

Icon: 100-voltage detection circuit; 101-a first voltage reduction unit; 102-a second voltage reduction unit; 103-a third voltage reduction unit; 104-a rectifying unit; 105-a voltage dividing unit; 106-a voltage stabilizing unit; 107-first relay; 108-a second relay; 109-safety unit; 110-a communication unit; 120-a switching unit; 200-an electric energy meter; 210-a metering unit; 300-voltage detection system.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "first", "second", "third", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1, fig. 1 is an exemplary block diagram of a voltage detection system 300 according to an embodiment of the present invention.

The voltage detection system 300 may include an electric energy meter 200, a voltage detection circuit 100 disposed in the electric energy meter 200, and a metering unit 210 disposed outside the electric energy meter 200, where the metering unit 210 is configured to collect a voltage at an output terminal of the voltage detection circuit 100. The actual power meter 200 needs to be powered on the user (i.e., power the load) or powered off the user by closing or opening the relay. Therefore, the voltage detection circuit 100 can add elements on the basis that the existing circuit has a relay to realize the voltage detection of the output end of the electric energy meter 200.

Further, the voltage at the output terminal of the voltage detection circuit 100 is collected by the metering unit 210 connected to the outside of the electric energy meter 200, and then, based on the comparison between the voltage value and the theoretical voltage value calculated by the metering unit 210 under each condition, each condition at the output terminal of the electric energy meter 200 can be determined.

For example, as shown in fig. 2, fig. 2 is an exemplary block diagram of a voltage detection circuit 100 in a voltage detection system 300 according to an embodiment of the present invention. The voltage detection circuit 100 comprises a first voltage reduction unit 101, a second voltage reduction unit 102, a third voltage reduction unit 103, a rectification unit 104, a voltage division unit 105, a voltage stabilization unit 106, a first relay 107 and a second relay 108 which are arranged in an electric energy meter 200, wherein the first voltage reduction unit 101, the second voltage reduction unit 102, the rectification unit 104, the third voltage reduction unit 103 and the voltage stabilization unit 106 are sequentially connected in series on a zero line, and the second voltage reduction unit 102 is connected in parallel with a load.

The first voltage reduction unit 101, the second voltage reduction unit 102 and the third voltage reduction unit 103 are all used for reducing the voltage between the zero line and the live line.

The rectifying unit 104 is configured to rectify the voltage dropped by the first voltage dropping unit 101.

The voltage dividing unit 105 is connected in parallel between the output end of the third voltage reducing unit 103 and the live line, and is configured to divide the voltage reduced by the third voltage reducing unit 103.

The output end of the voltage stabilizing unit 106 is externally connected to the metering unit 210, and the voltage stabilizing unit 106 is configured to stabilize the voltage divided by the voltage dividing unit 105 and output the voltage to the metering unit 210 for collection by the metering unit 210.

The first relay 107 is connected in parallel with the first voltage reduction unit 101, and the second relay 108 is connected in parallel between the output end of the second voltage reduction unit 102 and the live wire, and both the first relay 107 and the second relay 108 are closed to supply power to the load, or both the first relay 107 and the second relay 108 are opened to disconnect the power supply to the load.

The first voltage reduction unit 101, the second voltage reduction unit 102, the third voltage reduction unit 103, the rectification unit 104, the voltage division unit 105 and the voltage stabilization unit 106 are used for matching with the on-off of the first relay 107 and the second relay 108 to realize the detection of the output end of the electric energy meter 200.

For example, as shown in fig. 3, the first voltage-reducing unit 101 may be resistors R1, R2, and R3 connected in series in sequence, the second voltage-reducing unit 102 may be resistors R4, R5, and R6 connected in series in sequence, the third voltage-reducing unit 103 may be resistors R7, R8, and R9 connected in series in sequence, the rectifying unit 104 may be a diode VD1, the voltage-dividing unit 105 may be a resistor R10, and the voltage-stabilizing unit may be a diode VD2. When the first relay 107 and the second relay are closed, the first voltage reduction unit 101 and the third voltage reduction unit 103 are bypassed, the voltage between the zero line and the live line is set to be Vi, (i.e., the voltage between UN and UL in fig. 3 is set to be Vi), the Vi forms a loop through UN, a LOAD (i.e., LOAD in fig. 3), and UL, and the Vi supplies power to the LOAD through the loop, that is, supplies power to the user through the electric energy meter 200.

Further, a resistor and a capacitor (e.g., R11 and C1 in fig. 3) may be connected in parallel between the cathode and the hot line of VD2, when the first relay 107 and the second relay 108 are both closed, since the current is bypassed by the first relay 107 and the second relay 108 at this time, the voltage across VD2 will be less than 1.1v, vd2 enters the off state, and the VD2 cathode is pulled down to the ground by R11, and the signal at the VD2 cathode (e.g., the CHK point in fig. 3) is collected as a stable low-level signal by the metering unit 210 at this time.

Further, when the first relay 107 and the second relay 108 are both turned off, the voltage between the neutral line and the live line (i.e., the voltage Vi between UN and UL) may form a half-wave signal after passing through the first voltage-reducing unit 101, the second voltage-reducing unit 102, the rectifying unit 104, the third voltage-reducing unit 103, the voltage-dividing unit 105, and the voltage-stabilizing unit 106, and VD2 may be in a conducting state by configuring parameters of each element, and may have an effect of conducting in a half-sine cycle.

For example, the parameter of the configuration may be that Vi is 220V, the voltage drop of VD1 is subtracted from this value, the current is calculated through the resistors R1 to R10, and then the resistance values of R1 to R9 and R10 are adjusted, so that VD2 can be conducted by the voltage across R10.

The above operation makes the metering unit 210 detect that the signal at the CHK point is a signal with a half-sine cycle conducting, and the metering unit 210 calculates the actual voltage value Vchk' corresponding to the signal by collecting the signal and performing AD conversion. By calculating the actual voltage value Vchk 'and comparing the actual voltage value Vchk' with the voltage value Vchk at the theoretical CHK point, the value Vchk is calculated in advance according to the resistance values of the resistors of the first detecting unit and the second detecting unit and the value Vi under various conditions (for example, the conditions that the electric energy meter 200 does not supply power to users, the load end of the electric energy meter 200 is stolen by artificial short circuit, etc.) at the output terminal of the electric energy meter 200. In comparison, if the value of Vchk' is similar to the value of Vchk under a certain condition, the corresponding value of Vchk can be used to determine the condition of the output terminal of the electric energy meter 200.

The embodiment of the utility model provides a pair of voltage detection circuit 100 and system, through first voltage reduction unit 101, second voltage reduction unit 102, third voltage reduction unit 103, rectifier unit 104, partial pressure unit 105, voltage stabilization unit 106, the design of first relay 107 and second relay 108, the circuit is whole simple, the device that each unit used is the device commonly used, the logic is clear, with low costs and good reliability, the holistic PCB occupation space of circuit is little, be applicable to in the product that PCB overall arrangement pressure is big, it is more complicated to have solved traditional voltage detection circuit, the component kind of use is many, the big and higher problem of overall cost of space that PCB occupied.

Further, the voltage detection circuit 100 can enable the metering unit 210 externally connected to the electric energy meter 200 to collect the voltage at the output end of the metering unit in real time, so as to realize reliable detection of the voltage, and then subsequently, based on the detected voltage, the voltage detection circuit can compare the detected voltage with the theoretical voltage value calculated by the metering unit 210 under each condition to judge each condition of the output end of the electric energy meter, so that the electricity utilization safety is improved.

Referring to fig. 3, in an alternative embodiment, the first voltage-reducing unit 101, the second voltage-reducing unit 102, and the third voltage-reducing unit 103 each include a plurality of resistors connected in series, and each of the resistors is connected in series to a zero line.

For example, as shown in fig. 3, the first voltage-reducing unit 101 is resistors R1, R2, and R3 connected in series in this order, the second voltage-reducing unit 102 is resistors R4, R5, and R6 connected in series in this order, and the third voltage-reducing unit 103 is resistors R7, R8, and R9 connected in series in this order.

In an alternative embodiment, the rectifying unit 104 is a rectifying diode, an anode of the rectifying diode is connected to the output terminal of the second voltage-reducing unit 102, and a cathode of the rectifying diode is connected to the input terminal of the third voltage-reducing unit 103.

For example, as shown in fig. 3, the rectifying unit 104 is a rectifying diode VD1. Due to the complex environment of the user terminal, even a cable with a length of several hundred meters may be used, and at this time, the parasitic capacitance on the cable is large, and even after the first relay 107 and the second relay 108 are disconnected, the first voltage reduction unit 101 and the third voltage reduction unit 103 may be bypassed due to the ac characteristic of the parasitic capacitance, resulting in the failure of the detection circuit.

Therefore, by adding the rectifier diode VD1, when the field cable is long and reaches hundreds of meters and generates a large parasitic capacitance, the ac can be changed into dc by the VD1 rectification effect, and at this time, the parasitic capacitance is rapidly filled in a plurality of cycles, and simultaneously, 1S filtering can be added to the control command of the external metering unit 210 to ensure the normal operation of the whole detection circuit.

In an alternative embodiment, the voltage regulation unit 106 is a voltage regulation diode, an anode of the voltage regulation diode is connected to the output terminal of the third voltage reduction unit 103, and a cathode of the voltage regulation diode is connected to the metering unit 210.

For example, as shown in fig. 3, the voltage stabilizing unit 106 is a voltage stabilizing diode VD2. Before the signal at the output end of the third voltage-reducing unit 103 (i.e., the output end of R9 in fig. 4) is input into the metering unit 210 for being collected by the metering unit 210, VD2 will stabilize the signal, so that the metering unit 210 collects a relatively stable AD value.

In an alternative embodiment, the voltage dividing unit 105 is a voltage dividing resistor, and the voltage dividing resistor is connected in parallel between the output terminal of the third voltage dropping unit 103 and the live line. For example, as shown in fig. 3, the voltage dividing unit 105 is a voltage dividing resistor R10.

In an optional embodiment, a communication unit 110 is further disposed in the electric energy meter 200, the communication unit 110 is connected to the metering unit 210, and the communication unit 110 is configured to establish communication with the metering unit 210.

In this embodiment, the communication unit 110 can support RS485 communication, and in other embodiments, the communication unit 110 can support various wired and wireless communication means, such as power line carrier communication and/or mobile phone network communication.

Referring to fig. 4, in an alternative embodiment, the second voltage-reducing unit 102 is further connected in parallel to a switch unit 120, and the switch unit 120 is connected to the communication unit 110.

The switch unit 120 is used to establish or break communication with the communication unit 110 according to the closing or opening of the switch.

The switching unit 120 does not work in the normal operation mode of the electric energy meter 200, when the electric energy meter 200 needs to be maintained, the first relay 107 and the second relay 108 are disconnected, the switching unit 120 works, the second voltage reduction unit 102 is bypassed at the moment, the voltage at the load is 0, and the state of whether the electric energy meter 200 is maintained at the moment is represented by the work of the switching unit 120.

It should be noted that, when the electric energy meter 200 is maintained, an external power source needs to be connected to the output end of the electric energy meter 200 to supply power to corresponding maintenance equipment (for example, an electric screwdriver, etc.), and as shown in fig. 3, the voltage of the external power source is set to be Vn, and Vn is in phase with Vi.

Therefore, the theoretical voltage value Vchk at this CHK point, i.e., the value Vchk when the key unit operates, can be calculated in the presence of Vn with Vn in phase with Vi. The Vchk ' value in the actual state is detected, and the comparison of the Vchk ' value shows that the Vchk ' value is close to the theoretical voltage value Vchk, which indicates that the switching unit 120 is in operation, that is, the electric energy meter 200 is in maintenance operation.

Further, the switch unit 120 may be disposed on an outer surface of the power meter 200 as a separate module, for example, the switch unit 120 may be a key unit, and the key unit may communicate with the communication unit 110 in the power meter 200. When the electric energy meter 200 needs to be maintained, the key unit is pressed down, and the communication unit 110 sends a signal to the metering unit 210 externally connected to the electric energy meter 200. At this time, when Vn exists and Vn is in phase with Vi, the theoretical voltage value Vchk at the CHK point is calculated, the metering unit 210 collects the actual voltage value Vchk 'at the CHK point, and compares the value Vchk' to find that the value is close to the theoretical voltage value Vchk, which indicates that the switching unit 120 is in operation, that is, the electric energy meter 200 is in maintenance operation.

Meanwhile, since the switch unit 120 is not connected in parallel with the second voltage reduction unit 102, when the first relay 107 and the second relay 108 are disconnected, if the LOAD is stolen by a man-made short circuit, the second voltage reduction unit 102 is bypassed at this time, the voltage at the LOAD is 0, the theoretical voltage value Vchk at the CHK point can be calculated according to the situation that the LOAD is 0 in advance, the metering unit 210 collects the actual voltage value Vchk 'at the CHK point, and the theoretical voltage value Vchk is found to be close to the theoretical voltage value Vchk by comparing the value Vchk', so that the man-made short circuit electricity stealing of the LOAD can be judged. If the switch unit 120 is connected in parallel with the second voltage-dropping unit 102, and the voltage at the LOAD is 0, there are two cases that the LOAD is stolen by artificial short circuit or the switch unit 120 is closed.

Referring to fig. 5, in an alternative embodiment, the voltage detection circuit 100 further includes a safety unit 109, and the safety unit 109 includes a safety resistor and a safety capacitor.

The safety resistor and the safety capacitor are connected in parallel between the output end of the voltage stabilizing unit 106 and the live wire, and the safety unit 109 is configured to step down the voltage between the output end of the voltage stabilizing unit 106 and the live wire and output the voltage to the metering unit 210.

For example, as shown in fig. 3, the safety unit 109 includes a safety resistor R11 and a safety capacitor C1, and the safety capacitor C1 plays a role of filtering.

The following describes various cases of the voltage detection circuit 100 detecting the output terminal of the electric energy meter 200 with reference to the above contents:

first, the theoretical voltage value Vchk at the CHK point is calculated for various conditions that may exist at the output terminal of the electric energy meter 200 as follows:

when the resistance values of R1 to R9 are sufficiently large, the current of the whole circuit is small when the first relay 107 and the second relay 108 are closed, and at this time, the voltage drops of VD1 and VD2 are ignored, and there are:

in case one, when the load is not in operation, the first relay 107 and the second relay 108 are disconnected, and no external power source is connected to the second voltage reduction unit 102, that is, the electric energy meter 200 does not supply power to the user at this time, vchk can be calculated by the following formula:

vchk = Vi × R10/(R1 + R2+ R3+ R4+ R5+ R6+ R7+ R8+ R9+ R10) formula one

In case two, when the voltage at the load is 0, the first relay 107 and the second relay 108 are opened, and no external power is connected at the second voltage-reducing unit 102, that is, there are two cases where the load is stolen by a man-made short circuit or the switching unit 120 is closed, vchk can be calculated by the following formula:

vchk = Vi × R10/(R1 + R2+ R3+ R7+ R8+ R9+ R10) formula two

In case three, when the load operates, the first relay 107 and the second relay 108 are closed, and no external power source is connected to the second voltage reduction unit 102, that is, the electric energy meter 200 supplies power to the user, vchk can be calculated by the following formula:

vchk = Vi R10/{ R1+ R2+ R3+ [ (R4 + R5+ R6) × Rload ]/(R4 + R5+ R6+ Rl oad) + R7+ R8+ R9+ R10} formula three

Wherein Rload is the resistance of the load.

In case four, when the external power supply is connected to the second voltage reducing unit 102, the first relay 107 and the second relay 108 are disconnected, and the voltage Vn of the external power supply is in phase with Vi at this time, that is, it represents that the electric energy meter 200 is in the maintenance state at this time, vchk may be calculated by the following formula:

vchk = | Vi-Vn | × R10/(R1 + R2+ R3+ R7+ R8+ R9+ R10) formula four

In case five, when the external power source is connected to the second voltage-reducing unit 102, the first relay 107 and the second relay 108 are disconnected, and the voltage Vn of the external power source is opposite to Vi, the calculated value of Vchk at this time can evaluate the electrical performance of the metering unit 210, and Vchk can be calculated by the following formula:

vchk = (Vi + Vn) × R10/(R1 + R2+ R3+ R7+ R8+ R9+ R10) formula five

Next, after obtaining the theoretical voltage value Vchk under each condition, the metering unit 210 collects the actual voltage value Vchk 'at the CHK point, and compares the value Vchk' to find that the value Vchk is close to the theoretical voltage value Vchk under the first, second, and fourth conditions, which indicates that the terminal of the electric energy meter 200 belongs to the certain condition.

It should be noted that, in case three, since the value of Vchk is obtained from the above formula three, when the electric energy meter 200 supplies power to the user, the value of the user load Rload can be obtained by collecting the actual voltage value Vchk 'at the CHK point and substituting the actual voltage value Vchk' into the above formula three, so as to determine the size of the user load.

For the fifth case, since the electrical performance of the metering unit 210 can be evaluated in the fifth case, the switching unit 120 may be controlled not to operate at this time, the value of Vchk calculated by the above formula five is the maximum, and when the metering unit 210 is connected, it may be determined whether the metering unit 210 can normally operate at this time, so as to evaluate the electrical performance of the metering unit 210.

Further, since the Vchk value calculated in the fifth case is the maximum, at this time, an event may be generated according to the Vchk value and recorded in the metering unit 210, and if the actual voltage value Vchk' at the actually acquired CHK point is close to the Vchk value, the metering unit 210 will issue an alarm instruction to remind a field operator to further determine whether the electric energy meter 200 is abnormal.

The embodiment of the present invention further provides a voltage detection system 300, wherein the voltage detection system 300 includes an electric energy meter 200, a metering unit 210 and the voltage detection circuit 100 as in any one of the above embodiments, the voltage detection circuit 100 is disposed in the electric energy meter 200, the metering unit 210 is disposed outside the electric energy meter 200 and connected to the voltage detection circuit 100.

In an alternative embodiment, the metering unit 210 is an MCU.

The voltage detection circuit 100 and the metering unit 210 can detect the voltage at the output end of the electric energy meter 200, and based on the voltage, the theoretical voltage value calculated by the metering unit can be compared with the voltage value, so as to judge various conditions at the output end of the electric energy meter 200. The circuit has strong compatibility, and can also be applied to various output end voltage, load and switch scenes except the electric energy meter 200.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. The voltage detection circuit is characterized by comprising a first voltage reduction unit (101), a second voltage reduction unit (102), a third voltage reduction unit (103), a rectification unit (104), a voltage division unit (105), a voltage stabilization unit (106), a first relay (107) and a second relay (108) which are arranged in an electric energy meter (200), wherein the first voltage reduction unit (101), the second voltage reduction unit (102), the rectification unit (104), the third voltage reduction unit (103) and the voltage stabilization unit (106) are sequentially connected in series on a zero line, and the second voltage reduction unit (102) is connected with a load in parallel;

the first voltage reduction unit (101), the second voltage reduction unit (102) and the third voltage reduction unit (103) are all used for reducing the voltage between the zero line and the live line;

the rectifying unit (104) is used for rectifying the voltage reduced by the first voltage reducing unit (101);

the voltage dividing unit (105) is connected in parallel between the output end of the third voltage reducing unit (103) and the live wire, and is used for dividing the voltage reduced by the third voltage reducing unit (103);

the output end of the voltage stabilizing unit (106) is externally connected with a metering unit (210), and the voltage stabilizing unit (106) is used for stabilizing the voltage divided by the voltage dividing unit (105) and outputting the voltage to the metering unit (210) for collection by the metering unit (210);

the first relay (107) is connected with the first voltage reduction unit (101) in parallel, the second relay (108) is connected between the output end of the second voltage reduction unit (102) and the live wire in parallel, and the first relay (107) and the second relay (108) are closed to supply power to the load or opened to disconnect the power supply to the load.

2. The voltage detection circuit according to claim 1, wherein the first voltage reduction unit (101), the second voltage reduction unit (102), and the third voltage reduction unit (103) each include a plurality of resistors connected in series, and each of the resistors is connected in series to a neutral line.

3. The voltage detection circuit according to claim 2, wherein the rectifying unit (104) is a rectifying diode, an anode of the rectifying diode is connected to the output terminal of the second voltage-reducing unit (102), and a cathode of the rectifying diode is connected to the input terminal of the third voltage-reducing unit (103).

4. The voltage detection circuit according to claim 2, wherein the voltage regulator unit (106) is a zener diode, an anode of the zener diode is connected to the output terminal of the third voltage step-down unit (103), and a cathode of the zener diode is connected to the metering unit (210).

5. The voltage detection circuit according to claim 2, wherein the voltage divider unit (105) is a voltage divider resistor connected in parallel between the output terminal of the third voltage-dropping unit (103) and the live line.

6. The voltage detection circuit according to claim 1, wherein a communication unit (110) is further disposed in the electric energy meter (200), the communication unit (110) is connected to the metering unit (210), and the communication unit (110) is configured to establish communication with the metering unit (210).

7. The voltage detection circuit according to claim 6, wherein the second voltage reduction unit (102) is further connected in parallel with a switch unit (120), and the switch unit (120) is connected with the communication unit (110);

the switch unit (120) is used for establishing communication or disconnecting communication with the communication unit (110) according to the closing or opening of a switch.

8. The voltage detection circuit of claim 1, further comprising a safety unit (109), the safety unit (109) comprising a safety resistor and a safety capacitor;

the safety resistor and the safety capacitor are connected in parallel between the output end of the voltage stabilizing unit (106) and the live wire, and the safety unit (109) is used for reducing the voltage between the output end of the voltage stabilizing unit (106) and the live wire and then outputting the voltage to the metering unit (210).

9. A voltage detection system, characterized by comprising an electric energy meter (200), a metering unit (210) and a voltage detection circuit according to any one of claims 1-8, the voltage detection circuit being arranged within the electric energy meter (200), the metering unit (210) being arranged outside the electric energy meter (200) and being connected to the voltage detection circuit.

10. The voltage detection system according to claim 9, wherein the metering unit (210) is an MCU.

Images