Resistivity constant current power supply module

Abstract

The utility model discloses a resistivity constant current power supply module which comprises a synchronous signal isolation circuit, a shaping conditioning circuit, a microcontroller, a digital simulator, a power amplification and output buffer circuit, a communication interface circuit and a DC-DC power supply circuit, and the synchronous signal isolation circuit adopts A # and B # as input pins of external synchronous signals. The shaping and conditioning circuit is provided with a TB1 input end and a / INT output end, the microcontroller is provided with an external interrupt port PA7 connected with the / INT output end, the digital simulator is provided with an SPI serial data interface, the microcontroller is connected to the digital simulator through SI serial input and SO serial output, and the digital simulator is provided with an external interrupt port PA7 connected with the / INT output end. The output of the digital simulator and the output of the power amplification and output buffer circuit are connected with a wire, and the output of the power amplification and output buffer circuit is provided with an I-OUT interface.

Description

Technical Field

[0001] The utility model relates to the technical field of oil logging equipment, in particular to a resistivity constant current power supply module. Background Technique

[0002] Resistivity logging is the earliest and most basic logging method in geophysical logging methods. Resistivity logging is based on the resistivity difference of rocks and ores, and studies the borehole geological section by measuring the change of the artificial DC electric field along the borehole profile.

[0003] The basic principle of resistivity logging is to supply constant current to the bottom layer through the power supply electrodes A and B, forming a stable spherical electric field in the formation near the power supply electrodes. The distribution of the electric field current lines is affected by the conductivity difference of the surrounding rocks; at the same time, there are measurement electrodes M and N in the spherical electric field, which receive and measure the change of the weak potential difference signal between M and N in the electric field. After comparing and comprehensively analyzing with the measurement of other parameters of the same formation, the change curve of the resistivity along the wellbore moving with the fixed electrode arrangement can be understood, so as to calculate information such as the conductivity and porosity of the formation, and be used to identify rock types, aquifers, and oil and gas reservoirs, etc.

[0004] In related technologies, most resistivity logging instruments use fixed constant current sine wave power supply. The fixed constant current power supply cannot accurately measure the difference when measuring formations with a large resistivity change range, and the measurement dynamic range is low. Content of the Utility Model

[0005] In order to solve the above problems, the utility model provides a resistivity constant current power supply module to solve this problem.

[0006] To achieve the above object, the present application provides the following technical solutions:

[0007] A resistivity constant current power supply module includes a synchronous signal isolation circuit, a shaping and conditioning circuit, a microcontroller, a digital simulator, a power amplification and output buffer circuit, a communication interface circuit, and a DC-DC power supply circuit. The synchronous signal isolation circuit uses A# and B# as input pins for external synchronous signals. The shaping and conditioning circuit has a TB1 input terminal. The shaping and conditioning circuit has an / INT output terminal. The microcontroller has an external interrupt port PA7 connected to the / INT output terminal. The digital simulator has an SPI serial data interface. The microcontroller is connected to the digital simulator through SI serial input and SO serial output. There is a wire connecting the output of the digital simulator and the output of the power amplification and output buffer circuit. The output of the power amplification and output buffer circuit is provided with an I-OUT interface.

[0008] Further set as: The microcontroller exchanges data with the communication interface circuit through RX and TX, and the communication interface circuit is connected to the CAN bus through CANH and CANL.

[0009] Further set as: The synchronization signal isolation circuit includes an optocoupler U1. The A# and B# input pins are respectively connected to the positive input and negative input of the optocoupler U1. A resistor R2 is connected to the base of the optocoupler U1, and the other end of the resistor R2 is grounded. The collector of the optocoupler U1 is connected to the TB1 terminal. A resistor R3 is connected between the collector of the optocoupler U1 and the TB1 output terminal, and the other end of the resistor R3 is connected to the positive power supply. The emitter of the optocoupler U1 is grounded.

[0010] Further set as: The shaping and conditioning circuit includes a monostable flip-flop U2.1 and a D flip-flop U3 connected in series. The TB1 terminal is connected to the B pin of the monostable flip-flop U2.1. A capacitor C1 is connected to the C pin of the monostable flip-flop U2.1, and the other end of the capacitor C1 is connected to a resistor R4. The other end of the resistor R4 is connected to the positive power supply. A wire is connected between the capacitor C1 and the resistor R4, and the other end of this wire is connected to the RC pin of the monostable flip-flop U2.1. A resistor R5 is connected to the Q pin of the D flip-flop U3, and the resistor R5 is connected to the / INT output terminal. A resistor R6 is connected between the resistor R5 and the / INT output terminal, and the other end of the resistor R6 is grounded.

[0011] Further set as: The power amplification and output buffer circuit includes a low-pass filter U4.1 and a power amplifier U5 connected thereto. The digital simulator is connected to the non-inverting output terminal of the low-pass filter U4.1, and the I-OUT interface is connected to the output terminal of the power amplifier U5.

[0012] Further set as: The DC-DC power supply circuit supplies power to the entire system through VCC and VSS and is grounded through GND.

[0013] Further set as: The synchronization signal isolation circuit, shaping and conditioning circuit, microcontroller, digital simulator, power amplification and output buffer circuit, communication interface circuit, and DC-DC power supply circuit adopt thick film circuits with a thickness of more than 10 microns and DIP-28 dual in-line packages.

[0014] Further set as: The positive power supply connected to the resistor R3 and the resistor R4 is 15V.

[0015] Further set as: the optocoupler U1 uses an optocoupler U1 with the model number 4N25; the monostable flip-flop U2.1 uses a monostable flip-flop U2.1 with the model number CD4538; the D flip-flop U3 uses a D flip-flop U3 with the model number CD4013; the low-pass filter U4.1 uses a low-pass filter U4.1 with the model number OP2177ARMZ; the power amplifier U5 uses a power amplifier U5 with the model number STM32F103TBU6TR.

[0016] Further set as: the microcontroller uses a microcontroller with the model number STM32F103TBU6TR; the digital simulator uses a digital simulator with the model number TLV5638CDR.

[0017] Compared with the prior art, the beneficial technical effects of the present utility model are:

[0018] The present utility model can receive external synchronization signals and can work synchronously with other electrical logging instruments at the same frequency to reduce noise interference. The microcontroller (MCU) receives instructions from the external resistivity measurement circuit through the communication interface circuit (CAN), outputs a low current in the high-resistance layer, and outputs a high current in the low-resistance layer, greatly improving the dynamic range of formation resistivity measurement. At the same time, it improves the measurement accuracy of formation resistivity, can dynamically and automatically adjust the supply current in real time to improve the measurement range and measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is the circuit connection block diagram of the present utility model;

[0021] Figure 2 is the synchronization signal isolation circuit of the present utility model;

[0022] Figure 3 is the shaping and conditioning circuit of the present utility model;

[0023] Figure 4 is the power amplification and output buffer circuit of the present utility model;

[0024] Figure 5 is the microcontroller, digital simulator and communication interface circuit of the present utility model;

[0025] Figure 6This is the DC-DC power supply circuit of the present utility model;

[0026] Figure 7 This is the three-dimensional external view of the present utility model. Specific embodiments

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0028] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0029] Embodiment

[0030] Refer to Figures 1-7 , which discloses a resistivity constant current power supply module of the present utility model, including a synchronous signal isolation circuit, a shaping and conditioning circuit, a microcontroller (MCU), a digital simulator (DAC), a power amplification and output buffer circuit, a communication interface circuit (CAN), and a DC-DC power supply circuit;

[0031] The synchronous signal isolation circuit is used to reduce external noise interference and isolate other circuits and output a TTL square wave synchronous signal. The synchronous signal isolation circuit uses A# and B# as the input pins of the external synchronous signal. The shaping and conditioning circuit is provided with a TB1 input terminal for receiving the TTL square wave synchronous signal.

[0032] The shaping and conditioning circuit is used to remove the edge burrs of the TTL square wave synchronous signal. The shaping and conditioning circuit is provided with an / INT output terminal. The microcontroller is provided with an external interrupt port PA7 connected to the / INT output terminal. The TTL square wave synchronous signal enters the port PA7 through the / INT output terminal after being shaped and conditioned by the shaping and conditioning circuit, so as to trigger the external interrupt of the microcontroller. Under the periodic interruption of this signal, the microcontroller controls the digital simulator to output a 25Hz sine signal;

[0033] Specifically, the SRAM in the microcontroller stores a sine wave table. The digital simulator is updated with data at regular intervals by the TIM2 timer in the microcontroller. The microcontroller is responsible for executing program code to process data and control other circuit components.

[0034] The digital simulator has an SPI serial data interface. The microcontroller is connected to the digital simulator through SI serial input and SO serial output for data transmission and sending control signals to the digital simulator.

[0035] The output of the digital simulator is connected to the output of the power amplification and output buffer circuit by a wire. The power amplification and output buffer circuit has an I-OUT interface at its output. The sine signal output by the digital simulator passes through the power amplification and buffer circuit and finally outputs a constant current power supply signal through the I-OUT interface.

[0036] Furthermore, the microcontroller is provided with a general-purpose port for outputting a 25HZ square wave signal FB, and the square wave signal FB is used as a detection control signal for the resistivity measurement circuit.

[0037] The microcontroller also manages the communication interface circuit, exchanges data with the communication interface circuit through RX and TX, and the communication interface circuit is connected to the CAN bus through CANH and CANL to achieve data communication and receive current adjustment instructions.

[0038] The power supply of the entire module is provided by a DC-DC power circuit, which converts the 5V input voltage into the 3.3V voltage required by the microcontroller, digital simulator, communication interface circuit, etc., and can provide a maximum current of 2A. The DC-DC power circuit supplies power to the entire system through VCC and VSS and is grounded through GND.

[0039] In this embodiment, the main controller of the DC-DC power circuit adopts TPS40200Q of TI.

[0040] It is worth mentioning that the present utility model adopts a thick film circuit with a thickness of more than 10 microns and a DIP-28 dual in-line package. The thick film circuit deposits conductive, resistive or dielectric materials on an insulating substrate using screen printing technology to form circuit components and interconnections, which has significant advantages in terms of manufacturing process and cost, enabling the maximum operating temperature of the present utility model to reach 175°C.

[0041] The synchronous signal isolation circuit includes an optocoupler U1 of model 4N25. The A# and B# input pins are respectively connected to the positive input and negative input of the optocoupler U1. The base of the optocoupler U1 is connected to a resistor R2, and the other end of the resistor R2 is grounded. The collector of the optocoupler U1 is connected to the TB1 terminal. A resistor R3 is connected between the collector of the optocoupler U1 and the TB1 output terminal, and the other end of the resistor R3 is connected to the 15V positive power supply. The emitter of the optocoupler U1 is grounded.

[0042] The shaping and conditioning circuit includes a connected monostable flip-flop U2.1 and a D flip-flop U3. Among them, the model of the monostable flip-flop U2.1 is CD4538, and the model of the D flip-flop U3 is CD4013. The TB1 terminal is connected to the B pin of the monostable flip-flop U2.1. A capacitor C1 is connected to the C pin of the monostable flip-flop U2.1. The other end of the capacitor C1 is connected to a resistor R4. The other end of the resistor R4 is connected to the 15V positive power supply. A wire is connected between the capacitor C1 and the resistor R4, and the other end of this wire is connected to the RC pin of the monostable flip-flop U2.1; A resistor R5 is connected to the Q pin of the D flip-flop U3. The resistor R5 is connected to the / INT output terminal. A resistor R6 is connected between the resistor R5 and the / INT output terminal, and the other end of the resistor R6 is grounded;

[0043] The power amplification and output buffer circuit includes a low-pass filter U4.1 with the model of OP2177ARMZ and a power amplifier U5 with the model of OPA551UA / 2K5E4 connected thereto. The digital simulator is connected to the non-inverting output terminal of the low-pass filter U4.1, and the I-OUT interface is connected to the output terminal of the power amplifier U5;

[0044] In this embodiment, the model of the microcontroller is STM32F103TBU6TR. The microcontroller is based on the ARM 32-bit Cotex-M3 core, with a maximum operating frequency of 72MHz; up to 512KB of FLASH and 64KB of SRAM memory; two 12-bit D / A converters and three multi-channel 12-bit A / D converters; having multiple 16-bit timers and multiple communication interfaces. All GPIO ports can tolerate 5V signals. The digital simulator model is TLV5638CDR and uses 12-bit high resolution (DAC).

[0045] The working principle and beneficial effects of the present utility model are as follows:

[0046] The resistivity constant current power supply module can receive a sine wave or square wave signal with a signal frequency of 10 - 100HZ and a signal amplitude of ±15V as a synchronization signal. The main function of the synchronization signal is to synchronize with other electrical logging circuit signals and work at the same frequency to reduce signal interference. The present utility model can output a maximum 500mA sine wave constant current source. The output current size can be dynamically adjusted by real-time measuring the formation resistivity.

[0047] Specifically, the resistivity constant current power supply module receives an external synchronization signal. The external synchronization signal first enters the optocoupler U1 through pins A# and B#, and the optocoupler U1 outputs a TTL square wave synchronization signal. Then, through the signal shaping and conditioning circuit, the signal shaping and conditioning circuit removes the edge glitches of the TTL square wave synchronization signal. After the external synchronization signal is isolated and shaped, the high voltage signal with a high level of 15V is level-converted by the voltage division of resistor R5 and resistor R6, and a low voltage with a high level of 3.3V is output. Then, it enters the external interrupt port PA7 of the microcontroller. This signal is used to trigger the external interrupt of the microcontroller. Under the periodic interrupt of this drive signal, the microcontroller controls the digital simulator to output a sine wave signal of 25HZ. After passing through the low-pass filter U4.1, it is then input to the power amplifier U5, and finally, a constant current signal is output through the I-OUT interface.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A resistivity constant current power supply module, characterized in that: The invention comprises a synchronous signal isolation circuit, a shaping and conditioning circuit, a microcontroller, a digital simulator, a power amplifier and output buffer circuit, a communication interface circuit and a DC-DC power supply circuit. The synchronous signal isolation circuit adopts A# and B# as input pins of an external synchronous signal, the shaping and conditioning circuit is provided with a TB1 input terminal, the shaping and conditioning circuit is provided with a / INT output terminal, the microcontroller is provided with an external interrupt port PA7 connected to the / INT output terminal, the digital simulator has an SPI serial data interface, the microcontroller is connected to the digital simulator via an SI serial input and an SO serial output, the output of the digital simulator is connected to the output of the power amplifier and output buffer circuit via a wire, and the output of the power amplifier and output buffer circuit is provided with an I-OUT interface.

2. A resistivity constant current power supply module according to claim 1, characterized in that: The microcontroller exchanges data with the communication interface circuit through RX and TX, and the communication interface circuit is connected to the CAN bus through CANH and CANL.

3. A resistivity constant current power supply module according to claim 2, characterized in that: The synchronization signal isolation circuit includes a photocoupler U1, wherein the A# and B# input pins are respectively connected to the positive input and negative input of the photocoupler U1, the base of the photocoupler U1 is connected to a resistor R2, the other end of the resistor R2 is grounded, the electrode of the photocoupler U1 is connected to the TB1 end, a resistor R3 is connected between the electrode of the photocoupler U1 and the output end of TB1, the other end of the resistor R3 is connected to the positive power supply, and the emitter of the photocoupler U1 is grounded.

4. A resistivity constant current power supply module according to claim 3, characterized in that: The shaping and conditioning circuit includes a monostable trigger U2.1 and a D trigger U3 connected to each other, the TB1 end is connected to the B pin of the monostable trigger U2.1, the C pin of the monostable trigger U2.1 is connected to a capacitor C1, the other end of the capacitor C1 is connected to a resistor R4, the other end of the resistor R4 is connected to a positive power supply, a wire is connected between the capacitor C1 and the resistor R4, the other end of the wire is connected to the RC pin of the monostable trigger U2.1; the Q pin of the D trigger U3 is connected to a resistor R5, the resistor R5 is connected to the / INT output end, a resistor R6 is connected between the resistor R5 and the / INT output end, and the other end of the resistor R6 is grounded.

5. A resistivity constant current power supply module according to claim 4, characterized in that: The power amplification and output buffer circuit includes a low-pass filter U4.1 and a power amplifier U5 connected thereto. The digital simulator is connected to the in-phase output end of the low-pass filter U4.1, and the I-OUT interface is connected to the output end of the power amplifier U5.

6. A resistivity constant current power supply module according to claim 5, characterized in that: The DC-DC power supply circuit supplies power to the entire system through VCC and VSS and is grounded through GND.

7. A resistivity constant current power supply module according to claim 1, characterized in that: The synchronous signal isolation circuit, shaping and conditioning circuit, microcontroller, digital simulator, power amplification and output buffer circuit, communication interface circuit and DC-DC power supply circuit adopt thick film circuits of more than 10 microns and DIP-28 dual in-line package.

8. A resistivity constant current power supply module according to claim 6, characterized in that: The positive power supply connected to the resistor R3 and the resistor R4 is 15V.

9. A resistivity constant current power supply module according to claim 6, characterized in that: The photoelectric coupler U1 adopts a photoelectric coupler U1 of model 4N25; The monostable trigger U2.1 adopts a monostable trigger U2.1 of model CD4538; the D trigger U3 adopts a D trigger U3 of model CD4013; the low-pass filter U4.1 adopts a low-pass filter U4.1 of model OP2177ARMZ; the power amplifier U5 adopts a power amplifier U5 of model STM32F103TBU6TR.

10. The resistivity constant current power supply module according to claim 1, characterized in that: The microcontroller adopts a microcontroller of model STM32F103TBU6TR; the digital simulator adopts a digital simulator of model TLV5638CDR.

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