An electric field critical breakdown detection circuit and method for a high-frequency electric dehydration (salt) power supply device

Abstract

The application discloses a kind of electric field critical breakdown detection circuit and method of high-frequency electric dehydration (salt) power supply device, circuit includes high-frequency sampling signal precision shaping unit, electric field critical breakdown judging unit and digital control unit, high-frequency sampling signal precision shaping unit is for the high-frequency alternating current sampling signal of electric field that high-frequency current sampling unit is collected to be converted into high-frequency direct current sampling signal;Electric field critical breakdown judging unit is for judging the electric field critical state of high-frequency high-voltage alternating current pulse according to sampling current, to judge whether critical breakdown has occurred to electric field;Digital control unit is for generating D / A signal, processing high-frequency direct current sampling signal and processing the judgment result transmitted by the electric field critical breakdown judging unit.This circuit can accurately judge whether critical breakdown has occurred to electric field, and can prevent overcurrent signal, interference signal and the like generated by power switch device commutation instant from being misjudged as electric field critical breakdown.

Description

Technical Field

[0001] This invention relates to the field of crude oil dehydration / salting technology, and in particular to an electric field critical breakdown detection circuit and method for a high-frequency electric dehydration (salting) power supply device. Background Technology

[0002] The reason why dispersed water particles can remain suspended in crude oil and remain stable for a considerable period of time is because of the emulsion film surrounding them. This emulsion film has strong binding forces with both the dispersed water particles and the crude oil itself. To induce rapid sedimentation of the dispersed water particles, the emulsion film must be broken up. Generally, small dispersed water particles in crude oil contain positive and negative ions of salts. When a high-frequency, high-voltage alternating electric field is applied to the crude oil, these small dispersed water particles become polarized. These positive and negative ions move rapidly in opposite directions of the electric field, generating internal frictional heat that continuously overcomes the film's strength. The polarized small dispersed water particles combine to form larger dispersed water particles, accelerating sedimentation and separating the water from the emulsion. There is also an optimal frequency for the alternating electric field used for dehydration, at which the average impact force is strongest. Crude oil electro-dehydration relies on the action of an electric field to break up and dehydrate water-in-oil emulsions. Due to its high efficiency and speed, it is widely used in various oil fields.

[0003] When power switching devices frequently commutate, they inevitably generate large pulse currents, which can cause digital control units to misjudge them as critical breakdown of the electric field. In actual production, this misjudgment can make it difficult to establish a high-voltage AC pulse electric field, thus affecting the dehydration (saltification) efficiency of the electro-dehydration (saltification) system. Summary of the Invention

[0004] This invention proposes a critical breakdown detection circuit and method for the electric field of a high-frequency electric dehydration (salt) power supply device to address the frequent "electric field collapse" phenomenon in the crude oil electro-dehydration process. It can accurately determine whether the electric field has experienced critical breakdown and prevent overcurrent signals and interference signals generated during the commutation of power switching devices from being misjudged as critical breakdown of the electric field.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A critical breakdown detection circuit for an electric field in a high-frequency electric dehydration (salt) power supply device, the detection circuit comprising a high-frequency sampling signal precision shaping unit, an electric field critical breakdown judgment unit, and a digital control unit, wherein:

[0007] The input end of the high-frequency sampling signal precision shaping unit is connected to an external high-frequency current sampling unit, and the output end is connected to the electric field critical breakdown judgment unit and the digital control unit respectively, which is used to convert the high-frequency AC sampling signal collected by the high-frequency current sampling unit into a high-frequency DC sampling signal.

[0008] The electric field critical breakdown judgment unit is connected to the digital control unit and the high-frequency sampling signal precision shaping unit, respectively, and is used to judge the electric field critical state of the high-frequency high-voltage AC pulse based on current sampling, thereby judging whether the electric field has undergone critical breakdown.

[0009] The electric field critical breakdown judgment unit includes an overcurrent detection circuit, a timing generation circuit for shielded commutation overcurrent and interference signals, and a critical breakdown signal identification circuit, wherein:

[0010] The overcurrent detection circuit is connected to the output terminal of the high-frequency sampling signal precision shaping unit and is used to receive the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit.

[0011] The overcurrent detection circuit is also connected to the digital control unit to receive the D / A signal sent by the digital control unit;

[0012] The timing generation circuit for shielded commutation overcurrent and interference signals is connected to the digital control unit and is used to receive the timing generated by the digital control unit.

[0013] The critical breakdown signal identification circuit is connected to the timing generation circuit for shielded commutation overcurrent and interference signals and the overcurrent detection circuit, respectively. It is used to receive the commutation overcurrent signal, the shielding timing of the interference signal and the overcurrent detection result, and to determine whether the electric field has experienced critical breakdown. At the same time, the judgment result is fed back to the digital control unit.

[0014] The digital control unit is used to generate D / A signals, process high-frequency DC sampling signals, and process the judgment results transmitted by the electric field critical breakdown judgment unit.

[0015] A method for determining the critical breakdown of the electric field in a high-frequency electric dehydration (salt) power supply device, the method comprising:

[0016] Step 1: First, sample the high-frequency DC sampling signal output by the precision shaping unit through the A / D channel, and determine whether the sampled high-frequency DC sampling signal exceeds the preset current threshold.

[0017] Step 2: If the high-frequency DC sampling signal is less than the preset current threshold, continue sampling;

[0018] Step 3: If the high-frequency DC sampling signal is greater than the preset current threshold and the overcurrent occurs within the critical breakdown period, it is determined to be a commutation overcurrent or interference signal generated during the commutation of the power switching device, and sampling continues.

[0019] Step 4: If the high-frequency DC sampling signal is greater than the preset current threshold and the overcurrent does not occur within the critical breakdown time period, it is determined to be an electric field critical breakdown.

[0020] As can be seen from the technical solution provided by the present invention, the circuit can accurately determine whether the electric field has undergone critical breakdown, and can prevent overcurrent signals and interference signals generated during the commutation of power switching devices from being misjudged as critical breakdown of the electric field, thereby improving the efficiency of dehydration (salting) and achieving the goal of high stability, high reliability and high performance of the electric dehydration (salting) device. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the electric field critical breakdown detection circuit of a high-frequency electric dehydration (salt) power supply device provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of one implementation circuit of the electric field critical breakdown judgment unit described in this embodiment;

[0024] Figure 3 This is a schematic diagram of another implementation circuit of the electric field critical breakdown judgment unit described in this embodiment;

[0025] Figure 4 This is a flowchart illustrating the electric field critical breakdown judgment method of the high-frequency electric dehydration (salt) power supply device according to an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, and do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0027] like Figure 1 The diagram shows a schematic of the electric field critical breakdown detection circuit of a high-frequency electric dehydration (salt) power supply device according to an embodiment of the present invention. The detection circuit includes a high-frequency sampling signal precision shaping unit, an electric field critical breakdown judgment unit, and a digital control unit, wherein:

[0028] The input end of the high-frequency sampling signal precision shaping unit is connected to an external high-frequency current sampling unit, and the output end is connected to the electric field critical breakdown judgment unit and the digital control unit respectively, which is used to convert the high-frequency AC sampling signal collected by the high-frequency current sampling unit into a high-frequency DC sampling signal.

[0029] The electric field critical breakdown judgment unit is connected to the digital control unit and the high-frequency sampling signal precision shaping unit, respectively. It is used to judge the electric field critical state of the high-frequency high-voltage AC pulse based on current sampling, thereby judging whether the electric field has undergone critical breakdown; and it is not affected by overcurrent, interference and other signals generated during the commutation of power switching devices.

[0030] The electric field critical breakdown judgment unit includes an overcurrent detection circuit, a timing generation circuit for shielded commutation overcurrent and interference signals, and a critical breakdown signal identification circuit, wherein:

[0031] The overcurrent detection circuit is connected to the output terminal of the high-frequency sampling signal precision shaping unit and is used to receive the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit.

[0032] The overcurrent detection circuit is also connected to the digital control unit to receive the D / A signal sent by the digital control unit;

[0033] The timing generation circuit for shielded commutation overcurrent and interference signals is connected to the digital control unit and is used to receive the timing generated by the digital control unit.

[0034] The critical breakdown signal identification circuit is connected to the timing generation circuit for shielded commutation overcurrent and interference signals and the overcurrent detection circuit, respectively. It is used to receive the commutation overcurrent signal, the shielding timing of the interference signal and the overcurrent detection result, and to determine whether the electric field has experienced critical breakdown. At the same time, the judgment result is fed back to the digital control unit.

[0035] The digital control unit is used to generate D / A signals, process high-frequency DC sampling signals, and process the judgment results transmitted by the electric field critical breakdown judgment unit. In specific implementation, the main control chip of the digital control unit can be implemented using a high-speed DSP.

[0036] like Figure 1 As shown, the high-frequency sampling signal precision shaping unit specifically includes a second operational amplifier U2, a third operational amplifier U3, and a fourth operational amplifier U4, wherein:

[0037] The positive input terminal of the second operational amplifier U2 is connected to +VC via the fifth resistor R5 and the first diode D1; the positive input terminal of the second operational amplifier U2 is connected to -VC via the sixth resistor R6 and the second diode D2; the positive input terminal of the second operational amplifier U2 is connected to an external high-frequency current sampling unit; the negative input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2.

[0038] The positive input terminal of the third operational amplifier U3 is connected to the output terminal of the third operational amplifier U3 via the ninth resistor R9 and the fourth diode D4; the positive input terminal of the third operational amplifier U3 is connected to the tenth resistor R 10 The third diode D3 is connected to the output terminal of the third operational amplifier U3; the negative input terminal of the third operational amplifier U3 is connected to ground via the eighth resistor R8.

[0039] The positive input terminal of the fourth operational amplifier U4 is connected to the twelfth resistor R. 12 The anode of the fourth diode D4 is connected; the positive input terminal of the fourth operational amplifier U4 is connected to the thirteenth resistor R. 13 The output of the fourth operational amplifier U4 is connected to the output of the digital control unit; the negative input of the fourth operational amplifier U4 is connected to the eleventh resistor R. 11 It is connected to the cathode of the third diode D3.

[0040] like Figure 2 The diagram shown is a schematic of one implementation circuit of the electric field critical breakdown judgment unit described in this embodiment. It includes a first comparator U8, a first NOT gate U5, a first capacitor C1, a second NOT gate U6, and a first AND gate U7. The first NOT gate U5 and the second NOT gate U6 form a timing generation circuit to shield commutation overcurrent and interference signals; the first comparator U8 and the resistors form an overcurrent detection circuit; and the first AND gate U7 serves as a critical breakdown signal identification circuit.

[0041] The positive input of the first comparator U8 is the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit, and the negative input of the first comparator U8 is connected to the fifteenth resistor R. 15 Fourteenth resistor R 14 Connect to +VC and ground respectively;

[0042] The input terminal of the first NOT gate U5 is connected to the digital control unit; the output terminal of the first NOT gate U5 is connected to the sixteenth resistor R. 16 Connect to the input terminal of the second NOT gate U6;

[0043] The two ends of the first capacitor C1 are connected to ground and the input terminal of the second NOT gate U6, respectively.

[0044] The first AND gate U7 input terminal 1 is connected to the output terminal of the second NOT gate U6; the other input terminal 2 of the first AND gate U7 is connected to the output terminal of the first comparator U8.

[0045] like Figure 3 The diagram shown is another implementation circuit diagram of the electric field critical breakdown judgment unit described in this embodiment. The electric field critical breakdown judgment unit includes a second comparator U. 10 Second AND gate U 11 Second comparator U 10 As an overcurrent detection circuit; the second AND gate U 11 As a critical breakdown signal discrimination circuit, in which:

[0046] Second comparator U 10 The positive input terminal is the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit; the second comparator U 10 The negative input terminal is the D / A signal emitted by the digital control unit;

[0047] Second AND gate U 11 Input terminal 1 is connected to the digital control unit; the second AND gate U 11 The other input terminal 2 is connected to the second comparator U 10 The output terminal is connected; the second AND gate U 11 The output judgment result is sent to the digital control unit.

[0048] Based on the above detection circuit, embodiments of the present invention also provide a method for determining the critical breakdown of the electric field in a high-frequency electric dehydration (salt) power supply device, such as... Figure 4 The diagram shown is a flowchart of the method described in an embodiment of the present invention. The method includes:

[0049] Step 1: First, sample the high-frequency DC sampling signal output by the precision shaping unit through the A / D channel, and determine whether the sampled high-frequency DC sampling signal exceeds the preset current threshold. The preset current threshold is set according to different power levels.

[0050] Step 2: If the high-frequency DC sampling signal is less than the preset current threshold, continue sampling;

[0051] Step 3: If the high-frequency DC sampling signal is greater than the preset current threshold and the overcurrent occurs within the critical breakdown period, it is determined to be a commutation overcurrent or interference signal generated during the commutation of the power switching device, and sampling continues.

[0052] Step 4: If the high-frequency DC sampling signal is greater than the preset current threshold and the overcurrent does not occur within the critical breakdown time period, it is determined to be an electric field critical breakdown.

[0053] It is worth noting that the contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0054] The detection circuit and method described in the embodiments of the present invention have the following advantages:

[0055] (1) It can accurately determine whether the electric field has undergone critical breakdown, and can prevent overcurrent signals and interference signals generated during the commutation of power switching devices from being misjudged as critical breakdown of the electric field.

[0056] (2) It solved the problem of unstable electric field and improved the dehydration (salt) efficiency;

[0057] (3) The goal of high stability, high reliability and high performance of the electro-dehydration (salt) device has been achieved.

[0058] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A critical breakdown detection circuit for the electric field of a high-frequency electro-dehydration or electro-desalination power supply device, characterized in that, The detection circuit includes a high-frequency sampling signal precision shaping unit, an electric field critical breakdown judgment unit, and a digital control unit, wherein: The input end of the high-frequency sampling signal precision shaping unit is connected to an external high-frequency current sampling unit, and the output end is connected to the electric field critical breakdown judgment unit and the digital control unit respectively, which is used to convert the high-frequency AC sampling signal collected by the high-frequency current sampling unit into a high-frequency DC sampling signal. The electric field critical breakdown judgment unit is connected to the digital control unit and the high-frequency sampling signal precision shaping unit, respectively, and is used to judge the electric field critical state of the high-frequency high-voltage AC pulse based on current sampling, thereby judging whether the electric field has undergone critical breakdown. The electric field critical breakdown judgment unit includes an overcurrent detection circuit, a timing generation circuit for shielded commutation overcurrent and interference signals, and a critical breakdown signal identification circuit, wherein: The overcurrent detection circuit is connected to the output terminal of the high-frequency sampling signal precision shaping unit and is used to receive the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit. The overcurrent detection circuit is also connected to the digital control unit to receive the D / A signal sent by the digital control unit; The timing generation circuit for shielded commutation overcurrent and interference signals is connected to the digital control unit and is used to receive the timing generated by the digital control unit. The critical breakdown signal identification circuit is connected to the timing generation circuit for shielded commutation overcurrent and interference signals and the overcurrent detection circuit, respectively. It is used to receive the commutation overcurrent signal, the shielding timing of the interference signal and the overcurrent detection result, and to determine whether the electric field has experienced critical breakdown. At the same time, the judgment result is fed back to the digital control unit. The digital control unit is used to generate D / A signals, process high-frequency DC sampling signals, and process the judgment results transmitted by the electric field critical breakdown judgment unit. The high-frequency sampling signal precision shaping unit includes a second operational amplifier U2, a third operational amplifier U3, and a fourth operational amplifier U4, wherein: The positive input terminal of the second operational amplifier U2 is connected to +VC via the fifth resistor R5 and the first diode D1; the positive input terminal of the second operational amplifier U2 is connected to -VC via the sixth resistor R6 and the second diode D2; the positive input terminal of the second operational amplifier U2 is connected to an external high-frequency current sampling unit; the negative input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2. The positive input terminal of the third operational amplifier U3 is connected to the output terminal of the third operational amplifier U3 via the ninth resistor R9 and the fourth diode D4; the positive input terminal of the third operational amplifier U3 is connected to the tenth resistor R 10 The third diode D3 is connected to the output terminal of the third operational amplifier U3; the negative input terminal of the third operational amplifier U3 is connected to ground via the eighth resistor R8. The positive input terminal of the fourth operational amplifier U4 is connected to the twelfth resistor R. 12 The anode of the fourth diode D4 is connected; the positive input terminal of the fourth operational amplifier U4 is connected to the thirteenth resistor R. 13 The output of the fourth operational amplifier U4 is connected to the output of the digital control unit; the negative input of the fourth operational amplifier U4 is connected to the eleventh resistor R. 11 Connected to the cathode of the third diode D3; The electric field critical breakdown judgment unit includes a first comparator U8, a first NOT gate U5, a first capacitor C1, a second NOT gate U6, and a first AND gate U7. The first NOT gate U5 and the second NOT gate U6 form a timing generation circuit to shield commutation overcurrent and interference signals; the first comparator U8 and the resistor device form an overcurrent detection circuit; the first AND gate U7 serves as a critical breakdown signal identification circuit, wherein: The positive input of the first comparator U8 is the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit, and the negative input of the first comparator U8 is connected to the fifteenth resistor R. 15 Fourteenth resistor R 14 Connect to +VC and ground respectively; The input terminal of the first NOT gate U5 is connected to the digital control unit; the output terminal of the first NOT gate U5 is connected to the sixteenth resistor R. 16 Connect to the input terminal of the second NOT gate U6; The two ends of the first capacitor C1 are connected to ground and the input terminal of the second NOT gate U6, respectively. The first AND gate U7 input terminal 1 is connected to the second NOT gate U6 output terminal; the other input terminal 2 of the first AND gate U7 is connected to the first comparator U8 output terminal.

2. The electric field critical breakdown detection circuit of the high-frequency electro-dehydration or electro-desalination power supply device according to claim 1, characterized in that, The electric field critical breakdown determination unit includes a second comparator U. 10 Second AND gate U 11 Second comparator U 10 As an overcurrent detection circuit; the second AND gate U 11 As a critical breakdown signal discrimination circuit, in which: Second comparator U 10 The positive input terminal is the high-frequency DC sampling signal output by the high-frequency sampling signal precision shaping unit; the second comparator U 10 The negative input terminal is the D / A signal emitted by the digital control unit; Second AND gate U 11 Input terminal 1 is connected to the digital control unit; the second AND gate U 11 The other input terminal 2 is connected to the second comparator U 10 The output terminal is connected; the second AND gate U 11 The output judgment result is sent to the digital control unit.

3. A method for determining critical breakdown of the electric field in the electric field critical breakdown detection circuit as described in claim 1, characterized in that, The method includes: Step 1: First, sample the high-frequency DC sampling signal output by the precision shaping unit through the A / D channel, and determine whether the sampled high-frequency DC sampling signal exceeds the preset current threshold. Step 2: If the high-frequency DC sampling signal is less than the preset current threshold, continue sampling; Step 3: If the high-frequency DC sampling signal is greater than the preset current threshold and the overcurrent occurs within the critical breakdown period, it is determined to be a commutation overcurrent or interference signal generated during the commutation of the power switching device, and sampling continues. Step 4: If the high-frequency DC sampling signal is greater than the preset current threshold and the overcurrent does not occur within the critical breakdown time period, it is determined to be an electric field critical breakdown.

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