Direct current acquisition and wireless isolation circuit for electricity meter

Abstract

The utility model discloses a direct current acquisition and wireless isolation circuit used for an ammeter, comprising a main module, a current acquisition circuit, a voltage acquisition circuit, a power supply module, a display module, an RS485 module and a wireless communication module, one side of the current acquisition circuit is provided with a first isolation circuit, one side of the voltage acquisition circuit is provided with a second isolation circuit, and the first isolation circuit is connected with the second isolation circuit. The first isolation circuit, the second isolation circuit, the display module, the RS485 module and the wireless communication module are all connected with the main module, and the power supply module supplies power to the main module, the first isolation circuit, the second isolation circuit, the power supply module, the display module, the RS485 module and the wireless communication module. According to the utility model, the current and voltage acquisition is adopted to set the isolation circuit, and even if the current direction is reverse, the voltage short circuit condition cannot occur, so that the occurrence of short circuit burn-in and tripping faults caused by the wrong wiring direction on site can be effectively avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to a current collection circuit, specifically a direct current collection and wireless isolation circuit for an electric meter. BACKGROUND

[0002] At present, the main method for supervising current is current sampling technology, which includes direct sampling, such as the way of generating voltage drop when current flows through a shunt, and then sampling and determining through proportional amplification of an operational amplifier, and indirect sampling, such as taking samples through the conversion of electricity-magnetism-electricity by a current transformer such as a Hall. Effective regulation and control are realized by controlling the switching frequency and phase of electronic components during sampling. In order to ensure the normal operation of the circuit, during the process of large current sampling, due to the factors of space, current accuracy, stability and response time, a shunt and a current collection IC are often used for sampling to ensure the accuracy of current sampling.

[0003] Direct current meter current collection generally adopts the shunt method. The shunt may be connected to the positive terminal or the negative terminal. The positive and negative directions of voltage and current may be connected reversely in the field. Since no other circuit is usually additionally provided between the current and voltage circuits, once the reverse connection problem occurs, short circuit, machine burning and tripping failure caused by incorrect connection direction will occur in the field, which increases the difficulty of connection and requires higher technical requirements for the operator. SUMMARY

[0004] In order to solve the above technical problems, the utility model provides a direct current collection and wireless isolation circuit for an electric meter.

[0005] In order to solve the above technical problems, the utility model adopts the following technical scheme:

[0006] A direct current collection and wireless isolation circuit for an electric meter, comprising a main module, a current collection circuit, a voltage collection circuit, a power module, a display module, an RS485 module and a wireless communication module, a first isolation circuit is arranged on one side of the current collection circuit, a second isolation circuit is arranged on one side of the voltage collection circuit, the first isolation circuit, the second isolation circuit, the display module, the RS485 module and the wireless communication module are connected with the main module, and the power module provides power supply for the main module, the first isolation circuit, the second isolation circuit, the power module, the display module, the RS485 module and the wireless communication module.

[0007] As a further improvement, the first isolation circuit and the second isolation circuit each comprise an isolation chip U2 and an input part circuit connected with the isolation chip U2, the first isolation circuit has a first output circuit, and the second isolation circuit has a second output circuit.

[0008] As a further improvement, the input part circuit comprises capacitors C22, C23, C7, C14 and C20 connected in parallel on one side of the isolation chip U2, an inductor L2 is connected between the capacitor C7 and the capacitor C14, a transformer T is arranged on the other side of the isolation chip U2, the primary side of the transformer T is connected with the isolation chip U2, a capacitor C5 is connected between the two sides of the isolation chip U2, and the primary side of the transformer T is connected with the first isolation chip through the capacitors C24 and C6.

[0009] As a further improvement, the second output circuit of the second isolation circuit comprises diodes D2 and D3 connected on the secondary side of the transformer T, and the negative poles of the diodes D2 and D3 are connected with the parallelly connected capacitor C21 and resistor R35.

[0010] As a further improvement, the first output circuit of the first isolation circuit comprises diodes D4 and D5 connected on the secondary side of the transformer T, and the negative poles of the diodes D4 and D5 are connected with the parallelly connected capacitor C25 and resistor R36.

[0011] As a further improvement, the voltage acquisition circuit comprises a voltage acquisition chip IC2, one side of which is connected with resistors R3, R4, R24 and R32 connected in series, the resistor R32 is connected back to the voltage acquisition chip IC2, a positive terminal is formed between the resistors R3 and R4, a negative terminal is formed between the resistors R24 and R32, and the resistor R4 and the resistor R24 are grounded; the other side of the voltage acquisition chip IC2 is connected with two paths, one of which is connected with resistors R2 and R1, and the other of which is connected with resistors R31, R30, R29 and R28 in sequence, and the two paths are connected with the parallelly connected capacitor C3, capacitor C4, resistor R10 and resistor R27, which are all grounded.

[0012] As a further improvement, the current acquisition circuit comprises a current acquisition chip IC3, one side of which is connected with resistors R38, R40, R44 and R46 connected in series, the resistor R46 is connected back to the voltage acquisition chip IC3, the resistor R38 and the resistor R40 form a positive terminal, the resistor R44 and the resistor R46 form a negative terminal, and the resistor R40 and the resistor R44 are grounded; the other side of the voltage acquisition chip IC3 is connected with two paths, one of which is connected with a resistor R37, the resistor R37 is connected with a fuse FB1, the fuse FB1 is connected with a voltage-dependent resistor RV3, the other path is connected with a resistor R45, the resistor R45 is connected with a fuse FB2, the fuse FB2 is connected with a voltage-dependent resistor RV3, the resistor R37 and the resistor R45 are connected with a voltage stabilizing tube TVS3, and the capacitor C28, the capacitor C29, the resistor R39 and the resistor R43 are connected in parallel.

[0013] As a further improvement, the isolation chip is TPT7740, TPT7741 or TPT7742.

[0014] Compared with the prior art, the utility model has the following beneficial technical effects:

[0015] The current and voltage are isolated by the isolation circuit, so that even if the current direction is reversed, the voltage short circuit condition will not occur, which can effectively avoid the short circuit and tripping failure caused by the error of the wiring direction. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 It is a frame schematic view of the utility model;

[0017] Fig. 2 It is a combination schematic view of the current acquisition circuit and the first isolation circuit in the utility model;

[0018] Fig. 3 It is a combination schematic view of the voltage acquisition circuit and the first isolation circuit in the utility model. DETAILED DESCRIPTION

[0019] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0020] In the description of the present application, it needs to be understood that, if there are terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0021] In the description of the present application, it needs to be understood that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected. It can be mechanical connection, or electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] As Figs. 1-3 shown, a direct current acquisition and wireless isolation circuit for an electric meter includes a main module, a current acquisition circuit, a voltage acquisition circuit, a power module, a display module, an RS485 module and a wireless communication module. The current acquisition circuit is provided with a first isolation circuit on one side, and the voltage acquisition circuit is provided with a second isolation circuit on one side. The first isolation circuit, the second isolation circuit, the display module, the RS485 module and the wireless communication module are connected with the main module. The power module provides power supply for the main module, the first isolation circuit, the second isolation circuit, the power module, the display module, the RS485 module and the wireless communication module. The current acquisition circuit and the voltage acquisition circuit are isolated through their respective isolation circuits, so that even if the current direction is reversed, there will be no voltage short circuit condition, which can effectively avoid the occurrence of short circuit and tripping failure caused by incorrect wiring direction on site. The display module displays the parameters during operation, which is convenient for viewing. The wireless communication module can realize remote communication, and the RS485 module can be connected by bus.

[0023] The first isolation circuit and the second isolation circuit each comprise an isolation chip U2 and an input part circuit connected with the isolation chip U2, the first isolation circuit has a first output circuit, and the second isolation circuit has a second output circuit.

[0024] The input part circuit comprises a capacitor C22, a capacitor C23, a capacitor C7, a capacitor C14 and a capacitor C20 connected with one side of the isolation chip U2, the capacitor C22, the capacitor C23, the capacitor C7, the capacitor C14 and the capacitor C20 are connected in parallel, an inductor L2 is connected between the capacitor C7 and the capacitor C14, a transformer T is arranged on the other side of the isolation chip U2, a primary side of the transformer T is connected with the isolation chip U2, a capacitor C5 is connected between the two sides of the isolation chip U2, and the primary side of the transformer T is connected with the first isolation chip through a capacitor C24 and a capacitor C6.

[0025] The second output circuit of the second isolation circuit comprises a diode D2 and a diode D3 connected on a secondary side of the transformer T, and the negative poles of the diode D2 and the diode D3 are connected with a capacitor C21 and a resistor R35 connected in parallel.

[0026] The first output circuit of the first isolation circuit comprises a diode D4 and a diode D5 connected on a secondary side of the transformer T, and the negative poles of the diode D4 and the diode D5 are connected with a capacitor C25 and a resistor R36 connected in parallel.

[0027] The voltage collection circuit comprises a voltage collection chip IC2, one side of the voltage collection chip IC2 is connected with resistors R3, R4, R24 and R32 connected in series, the resistor R32 is connected back to the voltage collection chip IC2, a positive terminal is formed between the resistors R3 and R4, a negative terminal is formed between the resistors R24 and R32, and the resistors R4 and R24 are grounded; the other side of the voltage collection chip IC2 is connected with two paths, one of which is connected with resistors R2 and R1, and the other of which is connected with resistors R31, R30, R29 and R28 in sequence, and the two paths are connected with a capacitor C3, a capacitor C4, a resistor R10 and a resistor R27 connected in parallel, and the capacitor C3, the capacitor C4, the resistor R10 and the resistor R27 are grounded. The primary side of the transformer has a connection point 1, a connection point 2 and a connection point 3, the connection point 1 is connected with the connection point 2 through a capacitor C24, the connection point 3 is connected with the isolation chip U2 through a capacitor C6, and the connection point 1 and the connection point 2 are connected with the isolation chip U2.

[0028] The current collection circuit comprises a current collection chip IC3, one side of the current collection chip IC3 is connected with resistors R38, R40, R44 and R46 connected in series, the resistor R46 is connected back to the voltage collection chip IC3, a positive terminal is formed between the resistors R38 and R40, a negative terminal is formed between the resistors R44 and R46, and the resistor R40 and the resistor R44 are grounded; the other side of the voltage collection chip IC3 is connected with two paths, one of the two paths is connected with the resistor R37, the resistor R37 is connected with a fuse FB1, the fuse FB1 is connected with a voltage-dependent resistor RV3, the other path is connected with a resistor R45, the resistor R45 is connected with a fuse FB2, the fuse FB2 is connected with the voltage-dependent resistor RV3, a voltage stabilizing tube TVS3 is connected between the resistor R37 and the resistor R45, and a capacitor C28, a capacitor C29, a resistor R39 and a resistor R43 are connected in parallel.

[0029] The isolation chip is TPT7740, TPT7741 or TPT7742.

[0030] In the utility model, the current and the voltage are respectively isolated by the isolation circuit, so that the power supply short circuit caused by the positive and negative poles being connected in error is avoided.

[0031] It should be noted that the above only for the preferred embodiments of the present application, and not for limiting the present application, although the present application is described in detail with reference to the embodiments, for the person skilled in the art, it still can modify the technical solutions recorded in the foregoing embodiments, or equivalent replacement to part of the technical features, but any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A direct current acquisition and wireless isolation circuit for an electricity meter, characterized in that, The current acquisition circuit side is provided with a first isolation circuit, the voltage acquisition circuit side is provided with a second isolation circuit, the first isolation circuit, the second isolation circuit, the display module, the RS485 module and the wireless communication module are connected with the main module, and the power module provides power supply for the main module, the first isolation circuit, the second isolation circuit, the power module, the display module, the RS485 module and the wireless communication module.

2. The DC acquisition and wireless isolation circuit for an electricity meter of claim 1, wherein, The first isolation circuit and the second isolation circuit both comprise an isolation chip U2 and an input part circuit connected with the isolation chip U2, the first isolation circuit has a first output circuit, and the second isolation circuit has a second output circuit.

3. The DC acquisition and wireless isolation circuit for an electricity meter of claim 2, wherein, The input part circuit comprises a capacitor C22, a capacitor C23, a capacitor C7, a capacitor C14 and a capacitor C20 connected with the isolation chip U2, the capacitor C22, the capacitor C23, the capacitor C7, the capacitor C14 and the capacitor C20 are connected in parallel, an inductor L2 is connected between the capacitor C7 and the capacitor C14, the isolation chip U2 is provided with a transformer T, a primary side of the transformer T is connected with the isolation chip U2, a capacitor C5 is connected between the two sides of the isolation chip U2, and the primary side of the transformer T is connected with the first isolation chip through a capacitor C24 and a capacitor C6.

4. The DC acquisition and wireless isolation circuit for an electricity meter of claim 3, wherein, The second output circuit of the second isolation circuit comprises a diode D2 and a diode D3 connected on a secondary side of the transformer T, and the negative poles of the diode D2 and the diode D3 are connected with a capacitor C21 and a resistor R35 connected in parallel.

5. The DC acquisition and wireless isolation circuit for an electricity meter of claim 3, wherein, The first output circuit of the first isolation circuit comprises a diode D4 and a diode D5 connected on a secondary side of the transformer T, and the negative poles of the diode D4 and the diode D5 are connected with a capacitor C25 and a resistor R36 connected in parallel.

6. The DC acquisition and wireless isolation circuit for an electricity meter of claim 1, wherein, The voltage acquisition circuit comprises a voltage acquisition chip IC2, one side of the voltage acquisition chip IC2 is connected with resistors R3, R4, R24 and R32 connected in series, the resistor R32 is connected back to the voltage acquisition chip IC2, a positive terminal is formed between the resistors R3 and R4, a negative terminal is formed between the resistors R24 and R32, and the resistors R4 and R24 are grounded; the other side of the voltage acquisition chip IC2 is connected with two paths, one of which is connected with resistors R2 and R1, and the other of which is connected with resistors R31, R30, R29 and R28 in sequence, and the two paths are connected with capacitors C3, C4, a resistor R10 and a resistor R27 connected in parallel, and the capacitors C3, C4, the resistor R10 and the resistor R27 are grounded.

7. The DC acquisition and wireless isolation circuit for an electricity meter of claim 1, wherein, The current collection circuit comprises a current collection chip IC3, one side of the current collection chip IC3 is connected with resistors R38, R40, R44 and R46 connected in series, the resistor R46 is connected back to the voltage collection chip IC3, a positive terminal is formed between the resistors R38 and R40, a negative terminal is formed between the resistors R44 and R46, and the resistor R40 and the resistor R44 are grounded; the other side of the voltage collection chip IC3 is connected with two paths, one of which is connected with a resistor R37, the resistor R37 is connected with a fuse FB1, the fuse FB1 is connected with a pressure sensitive resistor RV3, the other path is connected with a resistor R45, the resistor R45 is connected with a fuse FB2, the fuse FB2 is connected with the pressure sensitive resistor RV3, a voltage stabilizing tube TVS3 is connected between the resistors R37 and R45, and a capacitor C28, a capacitor C29, a resistor R39 and a resistor R43 are connected in parallel.

8. The DC acquisition and wireless isolation circuit for an electricity meter of claim 2, wherein, The model of the isolation chip is TPT7740, TPT7741 or TPT7742.

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