PT power-taking open-loop protection circuit and power-taking device

Abstract

The embodiment of the utility model discloses a PT power-taking open-loop protection circuit and a power-taking device. The circuit comprises a resistor R1, a rectifier bridge BR1, a relay RELAY1, an operational amplifier U1A, a triode Q1, a voltage division circuit, a resistor R2 and a resistor R3. One end of the resistor R1 is connected with a positive electrode output end of the rectifier bridge BR1 and a direct current power supply end VDC, the other end of the resistor R1 is connected with an input pin of the relay RELAY1, a negative electrode output end of the rectifier bridge BR1 is connected with a ground wire pin of the relay RELAY1 and then is grounded GND, and two alternating current input ends of the rectifier bridge BR1 are respectively connected with a live wire end L and a zero wire end N. The utility model effectively solves the problem of rapid voltage rise in the abnormal open-loop state of PT power taking, and is simple in structure, low in cost, stable and reliable, and suitable for popularization and application.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of PT power supply, and in particular to a PT power supply open-loop protection circuit and a power supply device. Background Art

[0002] With the development of smart grids, power control systems are moving towards a highly intelligent direction. Potential Transformer (PT) power supply is increasingly widely used in power control systems. However, there is an open-loop problem in existing PT power supply applications. In the open-loop state, its output voltage is in a floating state, and the voltage will exceed the back-end load by several times, which will cause irreversible damage to the back-end. This problem needs to be solved urgently. Utility Model Content

[0003] In order to solve the related technical problems, the utility model provides a PT power taking open-loop protection circuit and a power taking device to solve the problems mentioned in the above background technology part.

[0004] To achieve the above purpose, the embodiment of the utility model adopts the following technical solutions:

[0005] In the first aspect, an embodiment of the utility model provides a PT power supply open-loop protection circuit, which includes: a resistor R1, a rectifier bridge BR1, a relay RELAY1, an operational amplifier U1A, a transistor Q1 and a voltage divider circuit; the voltage divider circuit includes a resistor R2 and a resistor R3; wherein, one end of the resistor R1 is connected to the positive output terminal of the rectifier bridge BR1 and the DC power supply terminal VDC, the other end of the resistor R1 is connected to the input pin of the relay RELAY1, the negative output terminal of the rectifier bridge BR1 is connected to the ground pin of the relay RELAY1 and then grounded GND, the two AC input terminals of the rectifier bridge BR1 are respectively connected to the live wire terminal L and the neutral wire terminal N, and the The power pin of relay RELAY1 is connected to the power supply VCC, the collector of the transistor Q1 is connected to the relay RELAY1, the emitter of the transistor Q1 is grounded GND, the base of the transistor Q1 is connected to the output end of the operational amplifier U1A, the positive power supply terminal of the operational amplifier U1A is connected to the power supply VCC, the negative power supply terminal of the operational amplifier U1A is grounded GND, the non-inverting input terminal of the operational amplifier U1A is connected to one end of the resistor R2 and one end of the resistor R3, the inverting input terminal of the operational amplifier U1A is connected to the reference voltage terminal VERF, the other end of the resistor R3 is grounded GND, and the other end of the resistor R2 is connected to the DC power supply terminal VDC.

[0006] As an optional implementation, the transistor Q1 is an NPN insulated gate bipolar transistor.

[0007] In a second aspect, an embodiment of the utility model provides a power taking device, which adopts the PT power taking open-loop protection circuit described in any one of the first aspects above.

[0008] The technical solution proposed in the embodiment of the utility model is a follow-up voltage detection, which has a fast response speed and a resistive load mode. It can adapt by increasing the load power according to the input power requirement without adding any peripheral circuits, and effectively solves the problem of rapid voltage rise in the abnormal open-loop state of PT power supply. The utility model has a simple structure, low cost, stability and reliability, and is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate and understand the technical solutions in the embodiments of the present invention, the following briefly introduces the background technology of the present invention and the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0010] Figure 1 This is a structural diagram of a PT power supply open-loop protection circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0011] In order to make the technical problems solved by the utility model, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0012] Embodiment 1

[0013] Please refer to Figure 1 As stated, Figure 1 The PT power supply open-loop protection circuit structure diagram provided by the embodiment of the utility model. As shown in the figure, the PT power supply open-loop protection circuit in this embodiment includes: resistor R1, rectifier bridge BR1, relay RELAY1, operational amplifier U1A, transistor Q1 and voltage divider circuit; the voltage divider circuit includes resistor R2 and resistor R3.

[0014] In this embodiment, one end of the resistor R1 is connected to the positive output terminal of the rectifier bridge BR1 and the DC power supply terminal VDC, the other end of the resistor R1 is connected to the input pin of the relay RELAY1, the negative output terminal of the rectifier bridge BR1 is connected to the ground pin of the relay RELAY1 and then grounded GND, the two AC input terminals of the rectifier bridge BR1 are respectively connected to the live wire terminal L and the neutral wire terminal N, the power supply pin of the relay RELAY1 is connected to the power supply VCC, the collector of the transistor Q1 is connected to the relay RELAY1, and the The emitter of the transistor Q1 is grounded GND, the base of the transistor Q1 is connected to the output end of the operational amplifier U1A, the positive power supply terminal of the operational amplifier U1A is connected to the power supply VCC, the negative power supply terminal of the operational amplifier U1A is grounded GND, the non-inverting input terminal of the operational amplifier U1A is connected to one end of the resistor R2 and one end of the resistor R3, the inverting input terminal of the operational amplifier U1A is connected to the reference voltage terminal VERF, the other end of the resistor R3 is grounded GND, and the other end of the resistor R2 is connected to the DC power supply terminal VDC.

[0015] In this embodiment, the transistor Q1 is an NPN insulated gate bipolar transistor.

[0016] During operation, when the input voltage of the live wire terminal L and the neutral wire terminal N is higher than the set voltage, the voltage of the DC power supply terminal VDC increases, and the rectifier bridge BR1 in the circuit is suitable for both AC and DC. The voltage divider circuit composed of resistors R2 and R3 changes with the change of the voltage of the DC power supply terminal VDC. When the divided voltage is higher than the reference voltage of the reference voltage terminal VERF, the control relay RELAY1 is opened, and the load resistor R1 is cut into the circuit, so that the output end presents a large load mode. Since the energy of the PT input end is limited, its input is in a clamped state, so that the back end will not be damaged due to the high input voltage after the input open-loop, and the protection effect is significant.

[0017] The PT power supply open-loop protection circuit proposed in the embodiment of the utility model effectively solves the problem of rapid voltage rise in the PT power supply under abnormal open-loop state, and has simple structure, low cost, stability and reliability, and is suitable for popularization and application.

[0018] Embodiment 2

[0019] The embodiment of the utility model provides a power taking device, which adopts the PT power taking open-loop protection circuit described in the above embodiment 1.

[0020] The power taking device proposed in the embodiment of the utility model adopts a PT power taking open-loop protection circuit to effectively solve the problem of rapid voltage rise in the PT power taking under abnormal open-loop state.

[0021] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A PT power supply open-loop protection circuit, characterized in that: The circuit comprises: a resistor R1, a rectifier bridge BR1, a relay RELAY1, an operational amplifier U1A, a transistor Q1 and a voltage divider circuit; the voltage divider circuit comprises a resistor R2 and a resistor R3; wherein one end of the resistor R1 is connected to the positive output end of the rectifier bridge BR1 and the DC power supply end VDC, the other end of the resistor R1 is connected to the input pin of the relay RELAY1, the negative output end of the rectifier bridge BR1 is connected to the ground pin of the relay RELAY1 and then connected to the ground GND, the two AC input ends of the rectifier bridge BR1 are respectively connected to the live wire end L and the neutral wire end N, the power supply pin of the relay RELAY1 is connected to the DC power supply end VDC, and the DC power supply end VDC is connected to the DC power supply end VDC. The power supply VCC, the collector of the transistor Q1 is connected to the relay RELAY1, the emitter of the transistor Q1 is grounded GND, the base of the transistor Q1 is connected to the output end of the operational amplifier U1A, the positive power supply terminal of the operational amplifier U1A is connected to the power supply VCC, the negative power supply terminal of the operational amplifier U1A is grounded GND, the non-inverting input terminal of the operational amplifier U1A is connected to one end of the resistor R2 and one end of the resistor R3, the inverting input terminal of the operational amplifier U1A is connected to the reference voltage terminal VERF, the other end of the resistor R3 is grounded GND, and the other end of the resistor R2 is connected to the DC power supply terminal VDC.

2. The PT power supply open-loop protection circuit according to claim 1, characterized in that: The transistor Q1 is an NPN insulated gate bipolar transistor.

3. A power extraction device, characterized in that: The power taking device adopts the PT power taking open-loop protection circuit described in any one of claims 1 or 2.

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