Electric leakage detection device for mining intrinsic safety type mining equipment

Abstract

The invention discloses a mining intrinsic safety type mining equipment electric leakage detection device, which comprises a power supply circuit module, a boost switch module and a differential current detection module, and is characterized in that the power supply circuit module is used for converting provided direct current into voltage output; the boost switch module is used for upgrading the voltage output by the power supply circuit module to form boost current, the boost switch module outputs the output boost current to two branches, one branch is directly input to the differential current detection module, and the other branch is input to the differential current detection module after passing through detected equipment; the differential current detection module can amplify different differential voltages by configuring different gains according to the currents input by the two branches, and then judges whether the detected object has an electric leakage condition. According to the scheme, electric leakage detection is carried out by adopting an additional direct-current power supply method, the electric leakage detection work of a power grid can be improved through the electric leakage detection method, and coal mine production operation is stabilized.

Description

Technical Field

[0001] The present invention relates to the technical field of detection devices, and particularly to a intrinsically safe mining excavation equipment leakage detection device. Background Art

[0002] With the high attention paid to the safety of coal mine power systems by people, the leakage detection technology for underground low-voltage power supply systems has become an effective technical means to maintain the safe and efficient operation of coal mine power grids. It detects abnormal signals and automatically disconnects faulty lines to ensure the safety of coal mine underground power grids.

[0003] Generally, the zero-sequence current and voltage method is used for leakage detection in underground power grids. The advantages of the zero-sequence current and voltage method are: leakage selection can be performed, and the faulty circuit can be effectively cut off. The disadvantages of the zero-sequence current and voltage method are: large equipment volume, high cost, and easy misoperation due to immature technology.

[0004] Therefore, the existing methods for equipment leakage detection have the technical problem of low reliability due to the above-mentioned defects. It can be seen that how to improve the reliability of equipment leakage detection methods is a problem to be solved in this field. Summary of the Invention

[0005] Aiming at the technical problem of low reliability existing in the existing equipment leakage detection methods, the purpose of the present invention is to provide a intrinsically safe mining excavation equipment leakage detection device, which can improve the power grid leakage detection work and stabilize the coal mine production operation through this leakage detection method, effectively overcoming the problems existing in the prior art.

[0006] To achieve the above purpose, the present invention provides a intrinsically safe mining excavation equipment leakage detection device, including a power supply circuit module, a boost switch module, and a differential current detection module. The power supply circuit module is used to convert the provided direct current into a voltage output. The power supply circuit module is connected to the boost switch module. The boost switch module is used to upgrade the voltage output by the power supply circuit module to form a boost current. The boost switch module outputs the output boost current to two branches respectively. One branch is directly input to the differential current detection module, and the other branch is input to the differential current detection module after passing through the device under test. The differential current detection module can amplify and obtain different differential voltages by configuring different gains according to the currents input by the two branches, and then judge whether there is a leakage in the object to be detected.

[0007] Further, the power circuit module includes a power chip, a first input unit, a second input unit, a first output unit, and a second output unit. The first input unit is used to input direct current, and the second input unit is grounded. The power chip converts the direct current into voltage and forms two branches through the first output unit and the second output unit for transmission. The first output unit is used to transmit to each detection chip, and the second output unit outputs an electrical signal to the boost switch circuit module for boosting.

[0008] Further, the boost switch module includes a piezoelectric tactile driver chip, an inductor, a third output unit, and a fourth output unit. The electrical signal output by the second output unit is output to the inductor, and the inductor outputs to the piezoelectric tactile driver chip. The boosted current output by the boost switch module enters the differential current detection module through two branches respectively via the first output unit and the second output unit.

[0009] Further, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor are provided between the third output unit and the input end of the differential current detection module. The output of the third output unit passes through the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, and the tenth resistor and then outputs to the differential current detection circuit.

[0010] Further, a twelfth resistor, a thirteenth resistor, a circuit under test, a fourteenth resistor, and a fifteenth resistor are provided between the fourth output unit and the input end of the differential current detection module. The output of the fourth output unit sequentially passes through the twelfth resistor and the thirteenth resistor and then accesses the pin of the circuit under test to test the object to be measured, and then outputs and passes through the fourteenth resistor and the fifteenth resistor and then inputs to the differential current detection module.

[0011] Further, the differential current detection module compares the currents of the two branches. If the resistance of the object to be detected is the resistance value of the tenth resistor or is open and infinite, the currents of the two branches are equal, and both the differential voltage and the output voltage are zero; as the resistance value decreases, the voltage increases; if the resistance value of the object to be detected drops to zero or is short-circuited, the voltage is the maximum at this time.

[0012] Further, an isolation module is cooperatively provided between the differential current detection module and the controller. The isolation module is a linear optocoupler chip, which ensures the high stability and high linearity of the linear optocoupler.

[0013] Further, a first operational amplifier and a second operational amplifier are respectively provided at the input end and the output end of the linear optocoupler chip. The two amplifiers cooperate with the surrounding resistor-capacitor elements to form an electrical isolation circuit, realizing the isolation of analog signals.

[0014] The leakage detection device for intrinsically safe mining excavation equipment provided by the present invention uses the additional DC power supply method for leakage detection. Compared with the zero-sequence current and voltage method, it is not only simpler and easier to implement, but also more reliable and effective. The leakage detection work of the power grid can be improved through this leakage detection method, and the stable operation of coal mine production can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0016] Figure 1 It is the electrical schematic diagram of the leakage detection device for the intrinsically safe mining excavation equipment of the present mine. SPECIFIC EMBODIMENTS

[0017] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific drawings.

[0018] Aiming at the technical problem of low reliability existing in the leakage detection method of existing equipment, the purpose of the present invention is to provide a leakage detection device for intrinsically safe mining excavation equipment, which uses the additional DC power supply method for leakage detection, that is, uses the DC added between the cable and the ground to detect whether there is a leakage fault in the cable. When the equipment is running normally, the insulation resistance value to the ground is very high, and the current of the additional DC detection circuit is very small, which is not enough to trigger the protection device to act. When the insulation level drops (leakage), the DC current increases and triggers the protection action. This protection principle can reliably detect the leakage fault of the motor circuit and is an effective method to realize the leakage protection of electrical equipment.

[0019] The leakage detection device for intrinsically safe mining excavation equipment provided by the present invention includes a detection circuit, a single-chip microcomputer digital circuit and an isolation circuit. The analog ground and the single-chip microcomputer digital ground of the detection circuit are isolated through the isolation circuit to realize the isolation of analog signals.

[0020] The detection circuit includes a power supply circuit module, a boost switch module and a differential current detection module.

[0021] Among them, the power supply circuit module is a DC-DC power supply module, which is used to convert the provided direct current into voltage and then output.

[0022] See Figure 1 , the power supply circuit module includes a power supply chip U29, a first input unit, a second input unit, a first output unit and a second output unit.

[0023] The first input unit is used to input 24V direct current, and the second input unit is connected to 0v current and connected to the GND of the power supply chip U29.

[0024] A first filtering unit is provided between the first input unit and the input of the power supply chip U29. After filtering the direct current input by the first input unit through the first filtering unit, it is transmitted to the power supply chip U29.

[0025] Among them, the first filtering unit is composed of a first filter B25, a first capacitor C118, a second capacitor C119, and a third capacitor C120 connected together, and they cooperate to form a filtering circuit for filtering the frequency of the output direct current.

[0026] The power supply chip U29 converts 24V direct current into 5V voltage and then forms two branches through the first output unit and the second output unit for transmission.

[0027] Furthermore, the first output unit is used to transmit to each detection chip. The first output unit is cooperatively provided with a second filtering unit composed of a fourth capacitor C121, a fifth capacitor C122, a sixth capacitor C123, and a first resistor R125. It can filter the alternating current signal, adjust and delay it, and then output it to each detection chip.

[0028] The second output unit outputs an electrical signal to the boost switch circuit module for boosting. A second filter B26 is cooperatively provided between the output of the second output unit and the input of the boost switch circuit module. The second filter B26 is used to filter the electrical signal input to the boost switch circuit module.

[0029] The boost switch module is used to boost the input electrical signal. It includes a piezoelectric tactile driver chip U30, an inductor L1, a third output unit, and a fourth output unit.

[0030] The EN pin of the piezoelectric tactile driver chip U30 is connected to the electrical signal output by the power supply circuit module, and a second resistor R127 is connected in series in the middle.

[0031] The GAIN1 and GAIN0 pins of the piezoelectric tactile driver chip U30 are connected to the electrical signal output by the power supply circuit module, and a third resistor R129 is connected in series in the middle.

[0032] The REXT pin of the piezoelectric tactile driver chip U30 is grounded, and a fourth resistor R130 is connected in series in the middle.

[0033] The electrical signal output by the second output unit is output to the inductor L1, and the inductor L1 outputs to the SW1 and SW2 pins of the piezoelectric tactile driver chip U30. When the electrical signal passes through the inductor L1, a magnetic field will be formed, and this magnetic field will store energy. When the input voltage changes, the magnetic field in the inductor L1 also changes accordingly, thereby generating an induced electromotive force and increasing the output voltage.

[0034] The piezoelectric tactile driver chip U30 here uses DRV8662, which integrates a boost power supply rail of a DC-DC converter inside. The boost operation does not require a transformer, only an inductor L1. When the level of the EN pin changes from low to high, the boost power supply switch is turned on, and the voltage of the V_BST pin can rise to between 15V and 105V.

[0035] The specific voltage regulation is determined by the boost feedback resistor of the V_BST pin and the resistor to ground of the FB pin:

[0036] V_Boost = V_FB(1 + R_1 / R_2) 【1】

[0037] Where V_FB = 1.32V, and the sum of R1 and R2 is recommended to be greater than 500kΩ and less than 1MΩ.

[0038] The peak current I_LIM passing through the inductor L1 is determined by the resistance of the R_EXT pin (the fourth resistor R130):

[0039] R_EXT = (K V_REF / I_LIM) - R_IN 【2】

[0040] Where K = 10500, V_REF = 1.35V, R_INT = 60Ω, and I_LIM is the desired peak current limit passing through the inductor.

[0041] A second filtering unit is provided between the output circuit of the power supply circuit module and the inductor L1. The second output unit outputs to the second filtering unit, and the second filtering unit filters the output electrical signal.

[0042] Here, the second filtering circuit is formed by connecting the third filter B27, the seventh capacitor C124, the eighth capacitor C126, and the ninth capacitor C127. They cooperate to form a filtering circuit for filtering the frequency of the output direct current.

[0043] The boost current output by the boost switch module outputs two branches through the third output unit and the fourth output unit respectively and enters the differential current detection module.

[0044] A third filtering circuit is provided at the output end of the boost switch module. The third filtering circuit is a filtering circuit formed by connecting the fourth filter B28, the fifth resistor R126, and the tenth capacitor C125, and is used for filtering the boost current output by the boost switch module.

[0045] Among them, a sixth resistor R154, a seventh resistor R153, an eighth resistor R152, a ninth resistor R151, and a tenth resistor R150 are provided between the third output unit and the input end of the differential current detection module. The output of the third output unit is output to the differential current detection circuit after passing through the sixth resistor R154, the seventh resistor R153, the eighth resistor R152, the ninth resistor R151, and the tenth resistor R150. The sixth resistor R154, the seventh resistor R153, the eighth resistor R152, the ninth resistor R151, and the tenth resistor R150 are connected in series.

[0046] A fourth filter circuit is cooperatively provided and filtered between the tenth resistor R150 and the differential current detection module. Here, the fourth filter circuit is a filter circuit formed by connecting a fifth filter B29, an eleventh resistor R147, and an eleventh capacitor C139, and is used to filter the boost current input to the differential current detection module.

[0047] A twelfth resistor R132, a thirteenth resistor R133, a detected circuit TP5, a fourteenth resistor R144, and a fifteenth resistor R143 are provided between the fourth output unit and the input end of the differential current detection module. The output of the fourth output unit is sequentially connected to the pin TP5 of the detected circuit after passing through the twelfth resistor R132 and the thirteenth resistor R133 to test the object to be measured, and then is input to the differential current detection module after passing through the fourteenth resistor R144 and the fifteenth resistor R143.

[0048] A fifth filter circuit is cooperatively provided and filtered between the fifteenth resistor R143 and the differential current detection module. Here, the fifth filter circuit is a filter circuit formed by connecting a sixth filter B30, a sixteenth resistor R149, and a twelfth capacitor C145, and is used to filter the boost current input to the differential current detection module.

[0049] A diode core U33 and a protection circuit formed by cooperating resistive-capacitive elements are connected in parallel in the circuits output by the third output unit and the fourth output unit, and are used for rectification, voltage stabilization, etc.

[0050] Here, the differential current detection module is a differential current detection chip U35, which can obtain different differential voltages and output voltages by amplifying through configuring different gains.

[0051] V_OUT = G(V_(+IN) - V_(-IN)) + V_REF 【3】

[0052] Where the gain G = 1 + R_2 / R_1

[0053] If the resistance of the object to be detected is the resistance value of the tenth resistor R150 or is open and infinite, the currents in the two branches are equal, and the differential voltage and the output voltage are both zero; as the resistance value decreases, the voltage increases; if the resistance value of the object to be detected drops to zero or is short-circuited, the voltage is the largest at this time. It has been proved by experiments that there is a good linear relationship between the two within a certain resistance range.

[0054] The voltage output by the differential current detection module is isolated and linearly converted by the isolation module and then sent to the core of the controller. Here, the isolation module is a linear optocoupler chip U31. A first operational amplifier U32 and a second operational amplifier U34 are respectively arranged at the input end and the output end of the linear optocoupler chip U31. The two amplifiers cooperate with the surrounding resistor-capacitor elements to form an electrical isolation circuit, realizing the isolation of analog signals.

[0055] At the same time, the linear optocoupler unit here uses an HCNR201 chip, and its internal structure ensures the high stability and high linearity of the linear optocoupler.

[0056] The controller can sense the resistance value of the object to be detected by sampling the voltage change, so as to judge whether there is a leakage situation in the motor loop to be detected. After the controller makes a sampling judgment, the action signal is sent to the high-voltage relay K5 through the I / O respectively, and the action instruction information is transmitted to the main control CPU module (PLC) of the roadheader electric control system equipment through the RS485 bus Modbus protocol.

[0057] For the mine intrinsically safe type mining equipment leakage detection device constituted by the above scheme, the following is an example to illustrate its working process in specific applications. It should be noted that this working process is only for example and does not limit this scheme.

[0058] It is independently powered by a DC 24V through the power module and is converted to 5V through DC-DC to supply power to each detection chip.

[0059] The boost switch circuit boosts the input voltage. When the level of the EN pin changes from low to high, the boost power supply switch is turned on. When the electrical signal passes through the inductor, a magnetic field will be formed, and this magnetic field will store energy. When the input voltage changes, the magnetic field in the inductor also changes accordingly, generating an induced electromotive force, causing the output voltage to increase. The voltage of the V_BST pin can rise between 15V and 105V. The specific voltage adjustment is determined by the boost feedback resistor of the V_BST pin and the resistor to ground of the FB pin.

[0060] The boost current enters the AD8237 through two branches. One branch passes through 4 resistors of 470 kΩ and a resistor of 150 kΩ, and the other branch passes through 4 resistors of 470 kΩ and the object to be detected such as the motor housing. The AD8237 differential current detection chip can obtain different differential voltages and output voltages by configuring different gains.

[0061] If the resistance of the object to be detected is 150 kΩ or open infinite, the currents in the two branches are equal, and both the differential voltage and the output voltage are zero; as the resistance value decreases, the voltage increases; if the resistance value of the object to be detected drops to zero or is short-circuited, the voltage is the largest at this time. This output voltage is isolated and linearly converted through the HCNR201 chip and then sent to the core of the stm32f407 controller. By sampling the voltage change, the controller can sense the resistance value of the object to be detected, so as to judge whether there is a leakage in the motor loop to be detected.

[0062] After the controller makes a sampling judgment, the action signals are transmitted to the high-voltage relay through I / O respectively, and the action instruction information is transmitted to the main control CPU module (PLC) of the roadheader electric control system equipment through the Modbus protocol of the RS485 bus.

[0063] The mine intrinsically safe mining equipment leakage detection device composed of the above scheme uses the additional DC power supply method to detect leakage. Compared with the zero-sequence current voltage method, it is not only simpler and easier to implement, but also more reliable and effective. This leakage detection method can be used to improve the power grid leakage detection work and stabilize the coal mine production operation.

[0064] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A mine intrinsically safe mining equipment leakage detection device, characterized in that: It includes a power circuit module, a boost switch module and a differential current detection module. The power circuit module is used to convert the provided direct current into a voltage output. The power circuit module is connected to the boost switch module. The boost switch module is used to upgrade the voltage output by the power circuit module to form a boost current. The boost switch module outputs the output boost current into two branches respectively, one branch is directly input into the differential current detection module, and the other branch is input into the differential current detection module after passing through the device under test. The differential current detection module can amplify different differential voltages by configuring different gains according to the currents input by the two branches, and then judge whether there is leakage in the object under test.

2. A leakage detection device for mining intrinsically safe mining equipment according to claim 1, characterized in that: The power circuit module includes a power chip, a first input unit, a second input unit, a first output unit and a second output unit. The first input unit is used to input direct current, and the second input unit is grounded. The power chip converts the direct current into voltage and the first output unit and the second output unit form two branches for transmission. The first output unit is used to transmit to each detection chip, and the second output unit outputs an electrical signal to the boost switch circuit module for boosting.

3. A leakage detection device for mining intrinsically safe mining equipment according to claim 1, characterized in that: The boost switch module includes a piezoelectric tactile driver chip, an inductor, a third output unit and a fourth output unit. The electrical signal output by the second output unit is output to the inductor, and the inductor is output to the piezoelectric tactile driver chip. The boost current output by the boost switch module is output to two branches through the first output unit and the second output unit respectively and enters the differential current detection module.

4. A leakage detection device for mining intrinsically safe mining equipment according to claim 3, characterized in that: A sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor are provided between the third output unit and the input end of the differential current detection module. The output of the third output unit passes through the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor and the tenth resistor and is output to the differential current detection circuit.

5. A mine intrinsically safe mining equipment leakage detection device according to claim 4, characterized in that: A twelfth resistor, a thirteenth resistor, a detected circuit, a fourteenth resistor, and a fifteenth resistor are provided between the fourth output unit and the input end of the differential current detection module. The output of the fourth output unit passes through the twelfth resistor and the thirteenth resistor in sequence and is connected to the pin of the detected circuit to test the object to be tested. Then, the output passes through the fourteenth resistor and the fifteenth resistor and is input into the differential current detection module.

6. A leakage detection device for mining intrinsically safe mining equipment according to claim 5, characterized in that: The differential current detection module compares the currents of the two branches. If the resistance of the object being detected is the resistance of the tenth resistor or is disconnected and infinite, the currents of the two branches are equal, and the differential voltage and the output voltage are both zero; as the resistance decreases, the voltage increases accordingly; if the resistance of the object being detected drops to zero or is short-circuited, the voltage is maximum at this time.

7. A mine intrinsically safe mining equipment leakage detection device according to claim 1, characterized in that: An isolation module is provided between the differential current detection module and the controller. The isolation module is a linear optocoupler chip, which ensures high stability and high linearity of the linear optocoupler.

8. A mine intrinsically safe mining equipment leakage detection device according to claim 7, characterized in that: The input end and the output end of the linear optocoupler chip are respectively provided with a first operational amplifier and a second operational amplifier. The two amplifiers cooperate with surrounding resistors and capacitors to form an electrical isolation circuit, thereby realizing the isolation of analog signals.

Images