CN111211549A

CN111211549A - Intrinsic safety output port surge protection circuit

Info

Publication number: CN111211549A
Application number: CN202010039615.0A
Authority: CN
Inventors: 陈辉; 陈向飞; 周远; 陈佩佩; 张兴华; 谢浩; 赵小兵; 刘冬
Original assignee: Tiandi Changzhou Automation Co Ltd; Changzhou Research Institute of China Coal Technology and Engineering Group Corp
Current assignee: Tiandi Changzhou Automation Co Ltd; Changzhou Research Institute of China Coal Technology and Engineering Group Corp
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2020-05-29

Abstract

The invention provides a surge protection circuit of an intrinsic safety output port, which comprises: the topological structure of the first-stage surge protection circuit and the topological structure of the second-stage surge protection circuit are connected in series, and the first inductor is a common-mode inductor. The surge protection circuit of the intrinsically safe output port meets the intrinsic safety requirement, can ensure that the output intrinsically safe circuit does not have the output protection phenomenon while realizing the surge protection function through the four-stage surge immunity test, and has the advantages of simple structure, good performance and convenient use.

Description

Intrinsic safety output port surge protection circuit

Technical Field

The invention relates to a protection circuit, in particular to a surge protection circuit for an intrinsically safe output port of a mining output intrinsic safety type power supply.

Background

The start and stop of high-power equipment, line faults, inductive load switching actions, the operation of frequency conversion equipment and the like in the coal mine power supply system can bring certain surge impact. The surge impact can bring adverse effect to the electric equipment, and the equipment is restarted, the data is lost or even the equipment is damaged.

The output intrinsic safety type power supply is used as a power supply of systems such as coal mine safety monitoring, personnel positioning, gas drainage and the like, and the reliability of the output power supply determines the stability of a supplied system. Due to the intrinsic safety requirement of the output intrinsic safety type power supply for the mine, the output port of the output intrinsic safety type power supply has an overvoltage and overcurrent protection function and limits the use of a large-capacity energy storage element. Therefore, the traditional surge protection circuit cannot be directly applied to the intrinsically safe output port of the output intrinsically safe power supply due to the fact that the traditional surge protection circuit has elements such as large differential mode inductance and the like. Moreover, because the traditional surge protection circuit has large residual voltage, the traditional surge protection circuit is directly applied to the intrinsically safe output port of the mining output intrinsically safe power supply, and the phenomena of output overcurrent and overvoltage protection still occur.

Disclosure of Invention

In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows: according to an embodiment of the present invention, there is provided an intrinsically safe output port surge protection circuit, including: the topological structure of the first-stage surge protection circuit and the topological structure of the second-stage surge protection circuit are connected in series, and the first inductor is a common-mode inductor.

In the above scheme, the topology of the first stage surge protection circuit includes: and the first capacitor is connected across the anode and the cathode of the intrinsic safety output port in a bridging manner.

In the above scheme, the first capacitor is a filter capacitor.

In the above scheme, the topology structure of the first stage surge protection circuit further includes: the second capacitor, the third capacitor, the fourth capacitor, the second capacitor includes first port and second port the third capacitor includes third port and fourth port, first port connects on this ampere of anodal of output port, the fourth port connects on this ampere of negative pole of output port, the fourth capacitor includes fifth port, sixth port, the second port with the third port with the fifth port is connected, the sixth port is connected with power shell.

In the above scheme, the second capacitor, the third capacitor and the fourth capacitor are all voltage-withstanding 3kV high-voltage ceramic chip capacitors.

In the above solution, the first inductor is a common mode inductor, and the inductance value is: 25 muH.

In the above scheme, the topology of the second-stage surge protection circuit includes: the device comprises a unidirectional TVS tube and a power resistor, wherein the unidirectional TVS tube is connected with the power resistor in parallel.

In the above scheme, the maximum reverse working voltage of the unidirectional TVS tube is higher than the intrinsic safety output voltage and does not exceed 2.0V.

In the scheme, the peak pulse power of the unidirectional TVS tube is 5 kW.

In the scheme, the power of the power resistor is 2W, and the resistance value of the power resistor is selected to ensure that the current flowing through the power resistor is 8mA-12mA under the condition that no surge is applied.

The surge protection circuit of the intrinsically safe output port meets the intrinsic safety requirement, can ensure that the output intrinsically safe circuit does not have the output protection phenomenon while realizing the surge protection function through the four-stage surge immunity test, and has the advantages of simple structure, good performance and convenient use.

Drawings

Fig. 1 is a schematic diagram of a surge protection circuit of an intrinsically safe output port according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. The following description is, therefore, to be understood as an extension of the idea of a person skilled in the art and not as a limitation of the invention.

In order to clearly describe all features of an actual embodiment. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific details must be set forth in order to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art.

The invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The gist and feature of the present invention will become apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to be construed as precise ratios as are necessary for a convenient and clear understanding of the embodiments of the present invention.

An embodiment of the present invention provides a surge protection circuit for an intrinsically safe output port, as shown in fig. 1, where fig. 1 is a schematic diagram of the surge protection circuit for the intrinsically safe output port provided in the embodiment of the present invention. This ampere of output port surge protection circuit includes: the topological structure of first order surge protection circuit, the topological structure of second level surge protection circuit, the topological structure of first order surge protection circuit with establish ties first inductance between the topological structure of second level surge protection circuit, first inductance is common mode inductance L1.

Optionally, the topology of the first stage surge protection circuit includes: the first capacitor C1 and the first capacitor C1 are connected across the positive pole Vout + and the negative pole Vout-of the intrinsic safety output port.

Optionally, the first capacitor C1 is a filter capacitor.

Optionally, the topology of the first stage surge protection circuit further includes: the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the second capacitor C2 includes a first port and a second port, the third capacitor C3 includes a third port and a fourth port, the first port is connected to a positive electrode Vout + of the output port, the fourth port is connected to a negative electrode Vout-, and the fourth capacitor C4 includes a fifth port and a sixth port, the second port is connected to the third port and the fifth port, and the sixth port is connected to the power supply housing.

Optionally, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 are all voltage-withstanding 3kV high-voltage ceramic chip capacitors.

Optionally, the first inductor L1 is a common mode inductor, and the inductance value is: 25 muH.

Optionally, the topology of the second-stage surge protection circuit includes: the device comprises a unidirectional TVS tube D1, a power resistor R1, and a unidirectional TVS tube D1 connected in parallel with the power resistor R1.

Optionally, the maximum reverse operation voltage of the unidirectional TVS tube D1 is not more than 2.0V higher than the intrinsic safety output voltage.

Optionally, the peak pulse power of the unidirectional TVS tube D1 is 5 kW.

Optionally, the power resistor R1 has power of 2W, and the R1 value is selected to ensure that the current flowing through the resistor is 8mA-12mA in the case of no surge applied.

The intrinsic safety output port surge protection circuit provided by the embodiment of the invention is applied to the intrinsic safety output port of the mine output intrinsic safety type power supply. The intrinsic safety output port surge protection circuit adopts a topological structure of a two-stage surge protection circuit, and an inductor is connected in series between the two-stage surge protection circuit to control a conduction time sequence. Because the use of a differential mode inductor with large capacity is limited by the intrinsic safety requirement of the mining output intrinsic safety type power supply, the L1 adopts a 25 muH common mode inductor with small inductance value, and the inductor plays the roles of inhibiting common mode interference and filtering while controlling the turn-on time sequence. However, since the inductance value of L1 is too small, L1 has a poor ability to suppress the on-timing when a surge is applied, and the first stage surge protection device is not needed.

The second stage protection adopts a unidirectional TVS tube D1 with lower residual voltage to suppress and clamp surge, and adopts a power resistor R1 to further absorb the residual voltage after D1.

Because 500VAC withstand voltage requirement exists between the intrinsic safety output and the power supply shell, at the first-stage surge protection position, the positive and negative stages of the output power supply are respectively connected with a second capacitor C2 and a third capacitor C3 of a Y capacitor with withstand voltage of 3kV to release common-mode surge, and the other ends of the second capacitor C2 and the third capacitor C3 are connected to the power supply shell through a fourth capacitor C4 of the Y capacitor with series withstand voltage of 3kV to improve withstand voltage, so that the Y capacitor is prevented from being broken down when common-mode surge is applied.

And at the first stage of surge protection, the positive and negative stages of an output power supply are connected with a first capacitor C1 of an X capacitor in parallel.

The unidirectional TVS tube D1 is a second-stage surge protection device and plays a role in clamping voltage and restraining differential mode surge. In order to obtain lower residual voltage, the D1 adopts a unidirectional TVS tube which is different from the traditional surge protection circuit, and the maximum reverse working voltage of the unidirectional TVS tube is not more than 2.0V higher than the intrinsic safety output voltage. Due to the absence of the first-stage surge absorption circuit, the D1 selects a high-power TVS with the peak pulse power of 5kW to resist the impact of the four-stage surge.

The first capacitor C1 is an output filter capacitor and has no surge protection function.

The power resistor R1 is a power resistor and is connected in parallel with the unidirectional TVS tube D1, and the power resistor R1 is used for further discharging surge energy and obtaining lower residual voltage. The power resistor R1 is typically selected to be a 2W power resistor. Depending on the operating voltage, the resistance of R1 is selected to ensure that the current flowing through the resistor is around 10mA without surge.

The overvoltage and overcurrent protection sensitivity of the intrinsic safety protection circuit is not set too high on the premise of ensuring intrinsic safety parameters, otherwise, the output protection phenomenon still easily occurs in surge and other EMC tests.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all modifications, equivalents, improvements and the like within the spirit and principle of the present invention should be included in the scope of the claims of the present application.

Claims

1. An intrinsically safe output port surge protection circuit, comprising: the topological structure of the first-stage surge protection circuit and the topological structure of the second-stage surge protection circuit are connected in series, and the first inductor is a common-mode inductor.

2. The intrinsically safe output port surge protection circuit of claim 1, wherein the topology of the first stage surge protection circuit comprises: and the first capacitor is connected across the anode and the cathode of the intrinsic safety output port in a bridging manner.

3. The intrinsically safe output port surge protection circuit of claim 2, wherein the first capacitor is a filter capacitor.

4. The intrinsically safe output port surge protection circuit of claim 2, wherein the topology of the first stage surge protection circuit further comprises: the second capacitor, the third capacitor, the fourth capacitor, the second capacitor includes first port and second port the third capacitor includes third port and fourth port, first port connects on this ampere of anodal of output port, the fourth port connects on this ampere of negative pole of output port, the fourth capacitor includes fifth port, sixth port, the second port with the third port with the fifth port is connected, the sixth port is connected with power shell.

5. The intrinsically safe output port surge protection circuit of claim 4, wherein the second capacitor, the third capacitor and the fourth capacitor are all high voltage ceramic chip capacitors capable of withstanding 3 kV.

6. The intrinsically safe output port surge protection circuit of claim 1, wherein the first inductor is a common mode inductor having an inductance value of: 25 muH.

7. The intrinsically safe output port surge protection circuit of claim 1, wherein the topology of the second stage surge protection circuit comprises: the device comprises a unidirectional TVS tube and a power resistor, wherein the unidirectional TVS tube is connected with the power resistor in parallel.

8. The intrinsically safe output port surge protection circuit of claim 7, wherein the unidirectional TVS tube maximum reverse working voltage is no more than 2.0V higher than the intrinsically safe output voltage.

9. The intrinsically safe output port surge protection circuit of claim 7, wherein the unidirectional TVS tube has a peak pulse power of 5 kW.

10. An intrinsically safe output port surge protection circuit as claimed in claim 7, wherein the power resistor is 2W in power and the resistance of the power resistor is chosen to ensure that the current flowing through the power resistor in the absence of an applied surge is 8mA-12 mA.