A high-voltage isolation detection alarm device

Abstract

The application provides a high-voltage isolation detection alarm device, which comprises a voltage sampling module for attenuating a collected high-voltage output signal into a low-voltage small signal, a signal processing module for processing the output of the voltage sampling module, a main control module for triggering an alarm module according to the signal output by the signal processing module, and the alarm module; the main control module comprises a dual-phase multi-threshold range comparator circuit and a trigger control circuit; the dual-phase multi-threshold range comparator circuit compares the output of the signal processing module according to different ranges to generate a trigger pulse signal to trigger a monostable trigger control circuit; and the trigger control circuit controls the alarm module to alarm. In the application, the dual-phase multi-threshold range comparator circuit is used to make the device a multi-threshold range high-voltage isolation detection alarm device, which meets the needs of users.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-voltage isolation detection alarm devices, in particular to a multi-threshold range high-voltage isolation detection alarm device. BACKGROUND

[0002] With the development of innovative technologies in China, high-voltage working is adopted in high-power equipment in the fields of rail transit, power grid, new energy, and industrial control. The detection control and alarm of these high-voltage power supply systems can ensure the safety of personnel and equipment.

[0003] For example, the overhead contact system of the rail transit power supply system needs to be isolated and detected in real time at 0.75KV, 1.5KV, and 3.6KV traction voltage. Once the traction voltage has a problem, the protection device will quickly disconnect the circuit breaker for protection treatment according to the alarm signal detected by the high-voltage isolation detection alarm device.

[0004] The rail potential of the rail transit power supply system is usually connected to the negative pole of the power supply grid. When the rail potential isolation detection alarm device detects that the voltage difference between the steel rail and the ground exceeds the set value (120V, 240V, 360V, 480V, 600V), the rail potential protection device controls the instantaneous short-circuit of the rail and the ground potential to release the voltage and current, thereby ensuring the safety of personnel and equipment on site.

[0005] Currently, a high-voltage isolation detection alarm device generally includes a voltage sampling module, a signal processing module, a main control module, and a warning module. The patent CN 115032444 A discloses such a high-voltage isolation detection device. The high-voltage isolation detection device samples the voltage of the measured circuit, processes the voltage signal, rectifies, amplifies, and peak filters the voltage signal, and then performs DC conditioning on the processed voltage to output a conditioning voltage signal with a preset voltage value. The conditioning voltage signal is then converted into a digital signal, and the digital signal is inversely operated based on a linear regression algorithm to obtain the corresponding voltage amplitude. The voltage amplitude is compared with the preset voltage threshold to determine whether the voltage signal of the measured circuit is a high-voltage signal. If the voltage signal of the measured circuit is not a high-voltage signal, a low-voltage warning signal is generated for alarm, thereby improving the accuracy of high-voltage warning. Since the overhead contact system of the rail transit power supply system needs to be isolated and detected in real time at different traction control voltages, different threshold values are needed for comparison. However, the above-mentioned high-voltage isolation detection alarm device is only a single threshold range and cannot meet the demand for multiple threshold ranges. SUMMARY

[0006] The present application provides a high-voltage isolation detection alarm device, which is a multi-threshold range high-voltage isolation detection alarm device, to address the problem that the current high-voltage isolation detection device is only a single threshold range and cannot meet the demand for multiple threshold ranges.

[0007] The technical scheme for achieving the technical purpose of the present application is: a high-voltage isolation detection alarm device, comprising a voltage sampling module for attenuating a collected high-voltage output signal into a low-voltage small signal, a signal processing module for processing the output signal of the voltage sampling module, a main control module for triggering an alarm module according to the signal output by the signal processing module, and the alarm module; the main control module comprises a dual-phase multi-threshold range comparator circuit and a trigger control circuit; the dual-phase multi-threshold range comparator circuit compares the output of the signal processing module with different ranges to generate a trigger pulse signal to trigger the monostable trigger control circuit; and the trigger control circuit controls the alarm module to alarm.

[0008] Further, in the high-voltage isolation detection alarm device described above: the dual-phase multi-threshold range comparator circuit comprises a digital potentiometer U2, a positive-phase multi-threshold range comparator, and a negative-phase multi-threshold range comparator.

[0009] The MCU control circuit outputs a control code to the digital potentiometer U2 to control the resistance ratio of the two groups of digital potentiometers of the digital potentiometer U2.

[0010] The positive-phase multi-threshold range comparator and the negative-phase multi-threshold range comparator compare the resistance ratio of the two groups of digital potentiometers with the measured signal output from the signal processing module to output a trigger signal.

[0011] Further, in the high-voltage isolation detection alarm device described above: the digital potentiometer U2 uses a chip of type AD8402ARZ50, and the MCU control circuit outputs control lines MCU-I / O-1, MCU-I / O-2, and MCU-I / O-3 to the 7th pin CS, the 8th pin SDI, and the 9th pin CLK of the digital potentiometer U2, respectively; the 5th pin and the 1st pin of the digital potentiometer U2 are connected to the reference ground of the input power supply of the device, the 6th pin and the 10th pin, and the 11th pin are connected to the input power supply Vcc1, the 14th pin and the 3rd pin are connected to the input power supply Vcc2, and the 12th pin and the 13th pin are connected to one end of the resistor R4, and the other end of the resistor R4 is connected to one end of the resistor R3 and one end of the resistor R7, and the 3rd pin of the negative-phase multi-threshold range comparator U3A.

[0012] The 2nd pin B2, the 4th pin W2, and the 3rd pin A2 of the digital potentiometer U2 constitute a second group of digital potentiometer outputs connected to the positive-phase multi-threshold range comparator.

[0013] The 14th pin B1, the 12th pin W1, and the 13th pin A1 of the digital potentiometer U2 constitute a first group of digital potentiometer outputs connected to the negative-phase multi-threshold range comparator.

[0014] Further, the high-voltage isolation detection alarm device described above: the positive-phase multi-threshold range comparator includes an operational amplifier U3B; the second group of digital potentiometer outputs of the digital potentiometer U2 are connected to the inverting input terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R5 and R1, and the measured signal output from the signal processing module is fed into the non-inverting input terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R6 and R9; the measured signal output from the signal processing module is connected to the output terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R6 and R8.

[0015] The inverting multi-threshold range comparator includes an operational amplifier U3A; the first group of digital potentiometer outputs of the digital potentiometer U2 are connected to the non-inverting input terminal of the operational amplifier U3A after being divided by the voltage dividing resistors R4 and R3, and the measured signal output from the signal processing module is fed into the inverting input terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R2 and R9; a resistor R7 is arranged between the non-inverting input terminal of the operational amplifier U3A and the output terminal of the operational amplifier U3A.

[0016] The output terminal of the operational amplifier U3A is connected to the anode of a diode D1, and the output terminal of the operational amplifier U3B is connected to the anode of a diode D2; the cathodes of the diode D1 and the diode D2 are connected and then output a trigger signal through a resistor R11.

[0017] Further, in the high-voltage isolation detection alarm device described above: the main control module further includes a pulse trigger driving circuit for pulse trigger driving the trigger signal output by the dual-phase multi-threshold range comparator circuit; the pulse trigger driving circuit includes a square wave oscillation circuit, a Schmitt inverter U12B, a Schmitt inverter U12C, a trigger signal feeding circuit, and a high-isolation embedded coupling transformer T1.

[0018] The trigger signal is connected to the base of a transistor Q11 through a current-limiting resistor R15, the collector of the transistor Q11 is connected to the input terminal of the square wave oscillation circuit, and the emitter is connected to the ground.

[0019] The output signals of the square wave oscillation circuit are respectively input to the input terminals of the Schmitt inverters U12B and U12C, the output terminals of the Schmitt inverters U12B and U12C are connected and then connected to the primary of the high-isolation embedded coupling transformer T1, and a pulse signal is output from the secondary of the high-isolation embedded coupling transformer T1.

[0020] Further, the high-voltage isolation detection alarm device has the square wave oscillation circuit, which comprises a Schmitt inverter U12A, a Schmitt inverter U12D, and the output end of the Schmitt inverter U12A is connected with the input end of the Schmitt inverter U12D, a resistor R14 is connected in series between the input end and the output end of the Schmitt inverter U12A, and a capacitor C12 is connected in series between the input end of the Schmitt inverter U12A and the output end of the Schmitt inverter U12D.

[0021] Further, the high-voltage isolation detection alarm device has the high-isolation embedded coupling transformer T1 arranged in the multi-layer PCB, which is a PCB-embedded high-isolation coupling transformer.

[0022] Further, the high-voltage isolation detection alarm device has the primary PCB coil, which is spirally coiled from outside to inside, and is connected with the primary PCB coil grounding shielding layer through a metallized via at the end of the inner coil.

[0023] The secondary PCB coil (40) is spirally coiled from outside to inside, and is connected with the secondary PCB coil grounding shielding layer (61) through a second metallized via (71) at the end of the inner coil, and the secondary PCB coil grounding shielding layer (61) is a large-area copper foil grounding shielding layer.

[0024] Further, the high-voltage isolation detection alarm device has the voltage sampling module, which comprises a high-voltage sampling voltage dividing circuit; the signal processing module comprises a low-pass filter circuit, a program-controlled preamplifier circuit and a program-controlled attenuation resistor array; the low-pass filter network circuit filters out the noise and interference in the sampling signal output by the high-voltage sampling voltage dividing circuit, and feeds the low-pass filtered signal into the program-controlled preamplifier circuit; the program-controlled preamplifier circuit is controlled by the MCU control circuit to adjust the gain resistor of the program-controlled amplifier circuit, and the output of the program-controlled preamplifier circuit is fed into the program-controlled attenuation resistor array; the program-controlled attenuation resistor array is adjusted by the MCU control circuit to adjust the resistance voltage dividing ratio of the program-controlled attenuation resistor array, and further attenuates and adjusts the collected voltage signal; and the alarm module comprises an LED alarm triggered by the trigger control circuit and a relay control alarm circuit.

[0025] In the application, the dual-phase multi-threshold range comparator circuit is used to make the device a multi-threshold range high-voltage isolation detection alarm device, which meets the needs of users.

[0026] The application will be described in greater detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0027] BRIEF DESCRIPTION OF DRAWINGS Figure 1 The principle block diagram of the multi-threshold range high-voltage isolation detection control alarm device;

[0028] BRIEF DESCRIPTION OF DRAWINGS Figure 2 The principle diagram of the dual-phase multi-threshold range comparator circuit;

[0029] BRIEF DESCRIPTION OF DRAWINGS Figure 3 The principle diagram of the trigger pulse driving circuit;

[0030] BRIEF DESCRIPTION OF DRAWINGS Figure 4 The structure diagram of the PCB embedded high-isolation coupling transformer. DETAILED DESCRIPTION

[0031] Embodiment 1: This embodiment is a multi-threshold range high-voltage isolation detection control alarm device for a rail transit power supply system, but it is not limited to the rail transit power supply system multi-threshold range high-voltage isolation detection control alarm device, and can also be used for high-voltage isolation detection alarm of other high-voltage and high-power power supply equipment.

[0032] As shown in Figure 1 , in this embodiment, the device includes a voltage sampling module that attenuates the collected high-voltage output signal into a low-voltage small signal, a signal processing module that processes the output of the voltage sampling module, a main control module that triggers the alarm module according to the signal output by the signal processing module, and an alarm module; the main control module includes a dual-phase multi-threshold range comparator circuit and a trigger control circuit.

[0033] The voltage sampling module includes a high-voltage sampling and dividing circuit; the signal processing module includes a low-pass filter network circuit, a program-controlled preamplifier circuit, and a program-controlled attenuation resistor array circuit; the main control module includes a dual-phase multi-threshold range comparator circuit, a trigger pulse driving circuit, a PCB embedded high-voltage isolation transformer, and a monostable trigger control circuit; the alarm module is an LED alarm and a relay control alarm circuit.

[0034] In this embodiment, the high-voltage resistance dividing sampling circuit attenuates the collected high-voltage output signal into a low-voltage small signal. Currently, using the dividing method to convert high-voltage signals into low-voltage signals for processing is a common method.

[0035] The low-voltage signal output by the high-voltage resistance voltage sampling circuit is fed into a subsequent low-pass filter network circuit, which filters noise and interference in the sampling signal, and feeds a low-pass filtered signal into a programmable preamplifier circuit. The programmable preamplifier circuit is controlled by the MCU control circuit to adjust the gain resistance of the programmable amplifier circuit, so as to meet the multi-threshold range amplitude adjustment of the multi-threshold range high-voltage isolation detection alarm device. After the measured voltage signal is output by the programmable preamplifier, it is fed into a programmable attenuation resistor array. The programmable attenuation resistor array is controlled by the MCU control circuit to adjust the resistance ratio of the programmable attenuation resistor array, so as to further attenuate and adjust the collected voltage signal. The multi-threshold range amplitude adjustment of the multi-threshold range high-voltage isolation detection alarm device is met. After the measured signal is adjusted by the programmable attenuation resistor array circuit, it is fed into a dual-phase multi-threshold range comparator circuit.

[0036] In this embodiment, the main control module is the key, and the dual-phase multi-threshold range comparator circuit changes the resistance ratio of the digital potentiometer U2 through the MCU control circuit, so as to change the threshold setting value of the dual-phase multi-threshold range comparator circuit. The dual-phase multi-threshold range comparator circuit outputs a trigger pulse signal through the dual-phase multi-threshold comparator circuit, and the trigger pulse signal is fed into a subsequent trigger pulse driving circuit. The digital potentiometer U2 uses a chip of AD8402ARZ50, which is a 2-group digital potentiometer.

[0037] In this embodiment, the dual-phase multi-threshold range comparator circuit is composed of a positive-phase multi-threshold range comparator, another negative-phase multi-threshold range comparator, and diodes or gates, as shown in Figure 2

[0038] The 6-pin reference comparison level of the operational amplifier U3B in the positive-phase multi-threshold range comparator is determined by the power supply voltage Vcc2, the 2nd group of digital potentiometers of the digital potentiometer U2, and the resistance R5 and R1 voltage dividing circuit. The MCU control circuit adjusts the resistance ratio of the 2nd group of digital potentiometers of the digital potentiometer U2, so as to adjust the threshold level of the positive-phase multi-threshold range comparator.

[0039] The threshold level hysteresis deviation of the positive-phase multi-threshold range comparator is determined by the 7-pin output voltage of the operational amplifier U3B at two different logic levels, through the positive feedback resistance R8 and the voltage dividing resistance R9. The difference between the upper offset value and the lower offset value of the positive threshold level is the threshold level hysteresis deviation of the positive-phase multi-threshold range comparator.

[0040] ​The 3-pin reference comparison level of the operational amplifier U3A in the inverting multi-threshold range comparator is determined by the power supply voltage Vcc2 and the 1st group of digital potentiometers of the digital potentiometer U2 and the voltage dividing circuit of resistors R4, R3. The MCU control circuit adjusts the resistance ratio of the 2nd group of digital potentiometers of the digital potentiometer U2, thereby adjusting the threshold level of the inverting multi-threshold range comparator.

[0041] The threshold level hysteresis deviation of the inverting multi-threshold range comparator is determined by the 1-pin output voltage of the operational amplifier U3A at two different logic levels, the positive feedback resistor R7 and the voltage dividing resistors R4, R3. The difference between the upper deviation value and the lower deviation value of the positive threshold level is the threshold level hysteresis deviation of the inverting multi-threshold range comparator.

[0042] In this embodiment, the specific circuit of the dual-phase multi-threshold range comparator circuit is shown in Figure 2 which is composed of the digital potentiometer U2, the non-inverting multi-threshold range comparator, the inverting multi-threshold range comparator and diode or gate, etc. The MCU control circuit outputs control codes to the 7-pin CS, 8-pin SDI and 9-pin CLK of the digital potentiometer U2. The resistance ratio of the two groups of digital potentiometers of the digital potentiometer U2 is adjusted to adjust the dual-phase multi-threshold range voltage of the DC high-voltage discharge device, thereby meeting the selection requirements of the dual-phase multi-threshold range voltage of the device.

[0043] The 6-pin reference comparison level of the operational amplifier U3B in the non-inverting multi-threshold range comparator is determined by the input power supply voltage Vcc2 and the 2nd group of digital potentiometers of the digital potentiometer U2 (B2, A2, W2 are the 2nd group of digital potentiometers) and the voltage dividing circuit of resistors R5, R6. The MCU control circuit adjusts the resistance ratio of the 2nd group of digital potentiometers of the digital potentiometer U2, thereby adjusting the threshold level of the non-inverting multi-threshold range comparator.

[0044] The threshold level hysteresis deviation of the non-inverting multi-threshold range comparator is determined by the 7-pin output voltage of the operational amplifier U3B at two different logic levels, the positive feedback resistor R8 and the voltage dividing resistor R9. The difference between the upper deviation value and the lower deviation value of the positive threshold level is the threshold level hysteresis deviation of the non-inverting multi-threshold range comparator.

[0045] The 3-pin reference comparison level of the inverting multi-threshold range comparator U3A is determined by the power supply voltage Vcc2 and the 1st group of digital potentiometers of the digital potentiometer U2 (W1, A1, B1 are the 1st group of digital potentiometers) and the voltage dividing circuit of resistors R4, R3. The MCU control circuit adjusts the resistance ratio of the 1st group of digital potentiometers of the digital potentiometer U2, thereby adjusting the threshold level of the inverting multi-threshold range comparator.

[0046] The threshold level hysteresis deviation of the inverting multi-threshold range comparator is the difference between the upper offset value and the lower offset value of the positive threshold level, which is determined by the positive feedback resistor R7, the voltage dividing resistors R4 and R3, when the 8-pin output voltage of U3A is at two different logic levels. The threshold level hysteresis deviation of the inverting multi-threshold range comparator is the difference between the upper offset value and the lower offset value of the positive threshold level.

[0047] In this embodiment, the specific connection of the dual-phase multi-threshold range comparator circuit is as shown in Figure 2

[0048] The positive multi-threshold range comparator includes an operational amplifier U3B; the 2 sets of digital potentiometer outputs of the digital potentiometer U2 are connected to the inverting input terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R5 and R1; the measured signal output from the signal processing module is fed into the non-inverting input terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R6 and R9; the measured signal output from the signal processing module is connected to the output terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R6 and R8;

[0049] The inverting multi-threshold range comparator includes an operational amplifier U3A; the 1 set of digital potentiometer outputs of the digital potentiometer U2 are connected to the non-inverting input terminal of the operational amplifier U3A after being divided by the voltage dividing resistors R4 and R3; the measured signal output from the signal processing module is fed into the inverting input terminal of the operational amplifier U3B after being divided by the voltage dividing resistors R2 and R9; the non-inverting input terminal of the operational amplifier U3A is connected to the output terminal of the operational amplifier U3A through the resistor R7;

[0050] The output terminal of the operational amplifier U3A is connected to the anode of the diode D1, and the output terminal of the operational amplifier U3B is connected to the anode of the diode D2; the cathodes of the diodes D1 and D2 are connected and then output a trigger signal through the resistor R11.

[0051] The output control lines MCU-I / O-1, MCU-I / O-2, MCU-I / O-3 of the MCU control circuit are respectively sent to the 7-pin CS, 8-pin SDI and 9-pin CLK of the digital potentiometer U2.

[0052] The 5-pin of the digital potentiometer U2 is connected to the reference ground of the input power supply of the device. The 11-pin of the digital potentiometer U2 is connected to the input power supply Vcc1 of the device, the 6-pin and the 10-pin of the digital potentiometer U2 are connected to the input power supply Vcc1 of the device, and the 1-pin of the digital potentiometer U2 is connected to the reference ground of the input power supply of the device.

[0053] ​The 14-pin of the digital potentiometer U2 is connected to the input power supply Vcc2 of the device, the 12-pin and 13-pin of the digital potentiometer U2 are connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the resistor R3 and one end of the resistor R7 and the 3-pin of the inverting multi-threshold range comparator U3A. The measured signal output by the programmable attenuating resistor array is fed into one end of the resistor R2, one end of the resistor R6 and one end of the resistor R9, the other end of the resistor R9 is connected to the reference ground of the input power supply of the device. The other end of the resistor R2 is connected to the 2-pin of the inverting multi-threshold range comparator U3A. The 8-pin of the non-inverting multi-threshold range comparator U3A is connected to the input power supply Vcc1 of the device. One end of the capacitor C1 is connected to the input power supply Vcc1 and the 8-pin of U3A. The other end of the capacitor C1 is connected to the reference ground of the input power supply of the device.

[0054] The 4-pin of the operational amplifier U3A in the non-inverting multi-threshold range comparator is connected to the reference ground of the input power supply of the device. The other end of the resistor R7 is connected to the 1-pin of the inverting multi-threshold range comparator U3A and the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2.

[0055] The 3-pin of the digital potentiometer U2 is connected to the input power supply Vcc2 of the device, the 2-pin and 4-pin of the digital potentiometer U2 are connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R1 and the 6-pin of the non-inverting multi-threshold range comparator U3B, the other end of the resistor R1 is connected to the reference ground of the input power supply of the device. The other end of the resistor R6 is connected to the 5-pin of the non-inverting multi-threshold range comparator U3B. The measured signal output by the programmable attenuating resistor array is fed into one end of the resistor R6, one end of the resistor R9 and one end of the resistor R8. The other end of the resistor R6 is connected to the 5-pin of the non-inverting multi-threshold range comparator U3B. The other end of the resistor R9 is connected to the reference ground of the input power supply of the device. The other end of the resistor R8 is connected to the positive electrode of the diode D2 and the 7-pin of the non-inverting multi-threshold range comparator U3B. The negative electrode of the diode D2 and the negative electrode of the diode D2 are connected to the resistor R11 to output the trigger signal.

[0056] If the single trigger pulse signal output by the dual-phase multi-threshold range comparator circuit is directly used to drive the PCB embedded high-voltage isolation transformer, that is, the single trigger pulse signal triggers the single-shot trigger control circuit behind the PCB embedded high-voltage isolation transformer, when the trigger pulse signal front edge is subjected to external high-frequency electromagnetic interference, the trigger pulse signal front edge may be distorted, resulting in loss or failure of the single trigger pulse signal. Therefore, a trigger pulse driving circuit is adopted here.

[0057] The trigger pulse driving circuit is as follows Figure 3As shown, is composed of the Schmitt inverter oscillation frequency of about 50 kHz Schmitt multivibrator. Schmitt multivibrator trigger pulse string signal feeding into two parallel Schmitt inverter, driving PCB embedded high-voltage isolation transformer.

[0058] In this embodiment, the trigger pulse drive circuit is a single trigger pulse signal output by the dual-phase multi-threshold range comparator circuit, which controls the power supply of the Schmitt multivibrator. When the trigger pulse signal passes through the switching transistor Q1 to turn on the ground 7 pin of the Schmitt inverter U12. A group of trigger pulse string signals are output by the Schmitt multivibrator composed of Schmitt inverters. When the front-end pulse signal of the trigger pulse string loses or fails due to external high-frequency electromagnetic interference, the pulse signal at the back end of the trigger pulse string can still pass through the PCB embedded high-voltage isolation transformer to continue to trigger the monostable trigger control circuit stably and reliably. Here chip U12 is a six-inverter, its 7 pin is VEE ground signal, the trigger signal is added to the Schmitt multivibrator through resistor R15 and transistor Q11, triggering the Schmitt multivibrator to oscillate.

[0059] The pulse trigger drive circuit is as shown: Figure 3 As shown: including square wave oscillator circuit, Schmitt inverter U12B, Schmitt inverter U12C, trigger signal feeding circuit, high-isolation embedded coupling transformer T1,

[0060] The trigger signal feeding circuit includes transistor Q11, the trigger signal passes through current-limiting resistor R15 to the base of transistor Q11, the collector of transistor Q11 is connected to the input of the square wave oscillator circuit, and the emitter is grounded; The output signal of the square wave oscillator circuit is input to the input terminals of Schmitt inverter U12B and Schmitt inverter U12C, and the output terminals of Schmitt inverter U12B and Schmitt inverter U12C are connected to the primary side of high-isolation embedded coupling transformer T1, and the pulse signal is output from the secondary side of high-isolation embedded coupling transformer T1.

[0061] In this embodiment, the square wave oscillator circuit includes Schmitt inverter U12A and Schmitt inverter U12D, the output terminal of Schmitt inverter U12A is connected to the input terminal of Schmitt inverter U12D, resistor R14 is connected in series between the input terminal and the output terminal of Schmitt inverter U12A, and capacitor C12 is connected in series between the input terminal of Schmitt inverter U12A and the output terminal of Schmitt inverter U12D.

[0062] Specifically, in the embodiment, the trigger pulse driving circuit is composed of a Schmitt inverter U12A, a Schmitt inverter U12D, a resistor R14 and a capacitor C12 to form a square wave oscillation circuit. The square wave output by the square wave oscillation circuit is output through U1B and U1C in parallel, and then is AC coupled through a capacitor C5 to drive a high-isolation embedded coupling transformer T1 to transmit the edge information of the PWM wave to the secondary monostable trigger control circuit.

[0063] The trigger pulse signal output by the dual-phase multi-threshold range comparator circuit is connected to the base of a switching triode Q11 through a resistor R15. The collector of the switching triode Q11 is connected to the pin 7 of the Schmitt inverter U12A. The emitter of the switching triode Q11 is connected to the reference ground of the input power supply in the embodiment. The pin 14 of the Schmitt inverter U12A is connected to the input power supply Vcc1. The pin 1 of the Schmitt inverter U12A is connected to one end of the resistor R14 and one end of the capacitor C12, respectively. The other end of the resistor R14 is connected to the pin 2 of the Schmitt inverter U12A and the pin 9 of the Schmitt inverter U12D. The other end of the capacitor C12 is connected to the pin 8 of the Schmitt inverter U12D, the pin 3 of the Schmitt inverter U12B and the pin 5 of the Schmitt inverter U12C. The pin 4 of the Schmitt inverter U12B and the pin 6 of the Schmitt inverter U12C are connected to one end of the capacitor C5. The other end of the capacitor C15 is connected to the pin 1 of the high-isolation embedded coupling transformer T1 and one end of the resistor R16. The pin 2 of the high-isolation embedded coupling transformer T1 and the other end of the resistor R16 are connected to the reference ground of the input power supply.

[0064] The PCB-embedded high-voltage isolation transformer is used to transmit the trigger pulse signal output by the trigger pulse driving circuit to the secondary PCB coil through electromagnetic coupling, and then trigger the monostable trigger control circuit.

[0065] The high-isolation PCB-embedded coupling transformer is arranged inside the multi-layer PCB. From top to bottom, there are a top layer PCB, a primary PCB coil, a large-area grounding shielding layer of the primary PCB coil, a large-area grounding shielding layer of the secondary PCB coil, a secondary PCB coil and a bottom layer PCB.

[0066] The primary PCB coil of the PCB-embedded high-voltage isolation transformer is spirally wound from outside to inside. At the end of the inner coil, the primary PCB coil is connected to the grounding shielding layer of the primary PCB coil through a metallized hole. The other end of the primary PCB coil is connected to the output of the trigger pulse driving circuit. The large-area grounding copper foil shielding layer of the primary PCB coil is connected to the reference ground of the trigger input end of the device through a metallized hole.

[0067] As shown in FIG. 1, the trigger pulse driving circuit is composed of a Schmitt inverter U12A, a Schmitt inverter U12D, a resistor R14 and a capacitor C12 to form a square wave oscillation circuit. The square wave output by the square wave oscillation circuit is output through U1B and U1C in parallel, and then is AC coupled through a capacitor C5 to drive a high-isolation embedded coupling transformer T1 to transmit the edge information of the PWM wave to the secondary monostable trigger control circuit. Figure 4As shown, the secondary PCB coil of the high-voltage isolation transformer embedded in the PCB spirals from the outside in, with both ends connected to the input port of the monostable trigger circuit. The large-area grounded copper foil shielding layer of the secondary PCB coil is connected to the reference ground of the trigger output terminal of this device through a metallized hole.

[0068] The high-isolation embedded coupling transformer T1 is a type of PCB embedded high-isolation coupling transformer installed inside a multi-layer PCB board. The PCB embedded high-isolation coupling transformer consists of the following components from top to bottom: top PCB 10, primary PCB coil 50, primary PCB coil grounding shield layer 60, secondary PCB coil large area copper foil grounding shield layer 61, secondary PCB coil 40, and bottom PCB 20.

[0069] The primary PCB coil 50 spirals from the outside to the inside, and at the end of the inner coil, it is connected to the primary PCB coil grounding shield 60 through a metallized via 70; the primary PCB coil grounding shield 60 is a large area copper foil grounding shield.

[0070] The secondary PCB coil 40 spirals from the outside in, and at the end of the inner coil, it is connected to the secondary PCB coil grounding shield 61 through the second metallized via 71. The secondary PCB coil grounding shield 61 is a large area copper foil grounding shield.

[0071] like Figure 4 The multilayer PCB shown has the following layers: the top layer is PCB10, the middle layer is the primary coil 50, the middle second layer is the primary coil grounding shield 60, the middle third layer is the secondary coil grounding shield 61, the middle fourth layer is the secondary coil 40, and the bottom layer is PCB20.

[0072] The primary PCB coil 50 spirals from the outside in, and at the end of the inner coil, it is connected to the grounding shield of the primary PCB coil through a metallized via 70. The other end is connected to the output of the trigger pulse drive circuit.

[0073] The secondary PCB coil 40 spirals from the outside in, with its two ends connected to the input terminals of the monostable trigger control circuit. The large-area copper foil grounding shield of the secondary PCB coil is connected to the reference ground of the trigger signal at the output terminal of this device through a metallized via 71.

[0074] The thickness of the substrate between the large-area grounding copper foil shielding layer 60 of the primary PCB coil and the large-area grounding copper foil shielding layer 61 of the secondary PCB coil ensures that the technical requirements for high-voltage isolation are met. The PCB substrate is made of FR4 board material, which has a high isolation voltage.

[0075] The interval of the PCB coil conductor, the number of turns of the PCB coil, the thickness of the copper foil of the PCB coil, the material of the PCB board, and the thickness of the PCB board are adjusted by simulation software to meet the set technical requirements, and then the quality factor is improved by optimization design to complete the design of the PCB embedded high-voltage isolation transformer.

[0076] 1. The process of embedding the coil in the PCB ensures the accuracy and stability of the self-resonant frequency of the PCB embedded high-voltage isolation transformer.

[0077] 2. The process of embedding the coil in the PCB obtains the maximum inductance in a limited space, and fully utilizes the middle 4-layer flat plate capacitance effect opposite to the primary and secondary coils to increase the stray capacitance of the coil and reduce the self-resonant frequency.

[0078] 3. The PCB embedded high-voltage isolation transformer fully utilizes the ordinary multi-layer PCB to achieve high insulation isolation, so that the isolation voltage reaches more than 20kV. Each group of coils uses a large-area copper foil grounding shielding layer, which has strong anti-interference ability and good electromagnetic compatibility.

[0079] In this embodiment, the monostable trigger circuit is a Schmidt monostable trigger composed of a 555 chip and other components. The pulse width time generated by the Schmidt monostable trigger is adjustable, and the width of the trigger pulse time can be adjusted by the RC charging and discharging time of the circuit. The output satisfies the requirements of the pulse width delay adjustable alarm signal.

[0080] The LED and relay alarm signal circuit displays the alarm signal through a group of contacts of a light-emitting diode and a solid-state relay. Another group of contacts of the solid-state relay is used to control the protection device.

[0081] In this embodiment, the power supply circuit is composed of an AC / DC conversion circuit, a PWM control circuit, a high-isolation flat transformer, an input rectification and filtering circuit, an input linear voltage stabilizing circuit, an output rectification and filtering circuit, and an output linear voltage stabilizing circuit.

[0082] In this embodiment, the MCU control circuit includes a MCU microprocessor, a memory, a timer, a reset circuit, and an I / O interface.

[0083] In this embodiment, the absolute value of the measured signal amplitude is compared with the set level threshold value. The trigger voltage signal obtained after comparison is transmitted to the output port control alarm circuit through the high-voltage isolation circuit. When the measured signal exceeds the set level threshold value, the relay of the output port of the device will change its port working state. The set level threshold value refers to the absolute value of the input detection alarm signal. When the measured signal exceeds the positive threshold value or the measured signal drops below the negative threshold value, the red LED light of the device is lit to alarm. The output relay A and B group ports will deliver a switching signal to the downstream control unit (such as PLC and other safety control equipment).

[0084] When the measured voltage rises to more than the positive threshold value, the LED lights up / the relay output port is in the overvoltage alarm control state. When the measured voltage from more than the positive threshold value offset value drops to the positive threshold value offset value above, the LED light is still on / the relay output port is still in the overvoltage alarm control state. When the measured signal continues to drop below the positive threshold value offset value, the LED light is off / the relay output port is in the no overvoltage alarm control state.

[0085] When the measured voltage is less than the negative threshold value offset value, the LED light is on / the relay output port is in the pressure alarm control state. When the measured voltage rises from less than the negative threshold value offset value to the negative threshold value offset value below, the LED light is still on / the relay output port is still in the pressure alarm control state. When the measured voltage continues to rise above the negative threshold value offset value, the LED light is off / the relay output port is in the no overvoltage alarm control state.

[0086] The threshold voltage range of the trigger signal of the embodiment is ± 50Vp-p ~ 5KVp-p.

[0087] The multi-threshold voltage range setting value of the embodiment is > 10 groups.

[0088] The measured input signal of the embodiment is positive and negative DC voltage or power frequency AC voltage.

[0089] The isolation voltage between the measured signal input end and the trigger control signal output end of the embodiment can reach AC 20kV, which is very suitable for application in high voltage and large current harsh electromagnetic application environment in rail transit power supply place. The device occupies very small PCB area, and is very easy to miniaturize.

[0090] The embodiment is vacuum filled in a module box of 67.5mm*99mm*110mm by high isolation epoxy resin, which can be buckled on the standard guide rail.

Claims

1. A high-voltage isolation detection alarm device, comprising a voltage sampling module for attenuating a collected high-voltage output signal into a low-voltage small signal, a signal processing module for processing the output of the voltage sampling module, a main control module for triggering an alarm module according to the signal output by the signal processing module, and the alarm module; characterized in that: The master control module comprises a dual-phase multi-threshold range comparator circuit, a trigger control circuit, and a pulse trigger driving circuit for pulse trigger driving of trigger signals output by the dual-phase multi-threshold range comparator circuit; the pulse trigger driving circuit comprises a square wave oscillation circuit, a Schmitt inverter U12B, a Schmitt inverter U12C, a trigger signal feeding circuit, and a PCB-embedded high-voltage isolation transformer T1; the dual-phase multi-threshold range comparator circuit generates trigger pulse signals to trigger the monostable trigger control circuit according to comparison of different ranges and outputs of the signal processing module; and the trigger control circuit controls the alarm module to alarm; The dual-phase multi-threshold range comparator circuit comprises a digital potentiometer U2, a positive-phase multi-threshold range comparator, and a negative-phase multi-threshold range comparator; The MCU control circuit outputs a control code to the digital potentiometer U2 to control the resistance ratio of the two groups of digital potentiometers of the digital potentiometer U2; The positive-phase multi-threshold range comparator and the negative-phase multi-threshold range comparator respectively compare the resistance ratio of the two groups of digital potentiometers with the measured signals output from the signal processing module and output trigger signals; The digital potentiometer U2 uses a chip of AD8402ARZ50, and the MCU control circuit outputs control lines MCU-I / O-1, MCU-I / O-2, and MCU-I / O-3 to the 7th pin CS, the 8th pin SDI, and the 9th pin CLK of the digital potentiometer U2, respectively; the 5th pin and the 1st pin of the digital potentiometer U2 are connected to a reference ground of an input power supply, the 6th pin and the 10th pin are connected to an input power supply Vcc1, the 14th pin and the 3rd pin are connected to an input power supply Vcc2, and the 12th pin and the 13th pin are connected to one end of a resistor R4, and the other end of the resistor R4 is connected to one end of a resistor R3 and one end of a resistor R7 and the 3rd pin of the negative-phase multi-threshold range comparator U3A, respectively; The 2nd pin B2, the 4th pin W2, and the 3rd pin A2 of the digital potentiometer U2 constitute a second group of digital potentiometer outputs connected to the positive-phase multi-threshold range comparator; The 14th pin B1, the 12th pin W1, and the 13th pin A1 of the digital potentiometer U2 constitute a first group of digital potentiometer outputs connected to the negative-phase multi-threshold range comparator; The positive-phase multi-threshold range comparator comprises an operational amplifier U3B; the second group of digital potentiometer outputs of the digital potentiometer U2 are connected to the inverting input end of the operational amplifier U3B through voltage division resistors R5 and R1, the measured signals output from the signal processing module are fed into the non-inverting input end of the operational amplifier U3B through voltage division resistors R6 and R9, and the measured signals output from the signal processing module are connected to the output end of the operational amplifier U3B through voltage division resistors R6 and R8; The inverse multiple threshold range comparator includes an operational amplifier U3A; the first group of digital potentiometer outputs of the digital potentiometer U2 are connected to the non-inverting input terminal of the operational amplifier U3A through voltage division resistors R4 and R3; the measured signal output from the signal processing module is fed into the inverting input terminal of the operational amplifier U3B through voltage division resistors R2 and R9; a resistor R7 is arranged between the non-inverting input terminal of the operational amplifier U3A and the output terminal of the operational amplifier U3A; The output terminal of the operational amplifier U3A is connected to the anode of a diode D1, and the output terminal of the operational amplifier U3B is connected to the anode of a diode D2; the cathodes of the diodes D1 and D2 are connected and then output a trigger signal through a resistor R11.

2. The high voltage isolation detection alarm apparatus according to claim 1, wherein: The trigger signal feeding circuit includes a transistor Q11, the trigger signal is connected to the base of the transistor Q11 through a current limiting resistor R15, the collector of the transistor Q11 is connected to the input terminal of the square wave oscillation circuit, and the emitter is connected to the ground; The output signal of the square wave oscillation circuit is input to the input terminals of the Schmitt inverter U12B and the Schmitt inverter U12C, the output terminals of the Schmitt inverters U12B and U12C are connected and then connected to the primary side of the PCB embedded high-voltage isolation transformer T1, and a pulse signal is output from the secondary side of the PCB embedded high-voltage isolation transformer T1.

3. The high voltage isolation detection alarm apparatus of claim 2, wherein: The square wave oscillation circuit includes the Schmitt inverters U12A and U12D, the output terminal of the Schmitt inverter U12A is connected to the input terminal of the Schmitt inverter U12D, a resistor R14 is connected in series between the input and output terminals of the Schmitt inverter U12A, and a capacitor C12 is connected in series between the input terminal of the Schmitt inverter U12A and the output terminal of the Schmitt inverter U12D.

4. The high voltage isolation detection alarm apparatus of claim 3, wherein: The PCB embedded high-voltage isolation transformer T1 is arranged inside a multi-layer PCB board, which is a PCB embedded high-voltage isolation coupling transformer; from top to bottom, the PCB embedded high-voltage isolation coupling transformer is a top layer PCB (10), a primary PCB coil (50), a primary PCB coil grounding shielding layer (60), a large-area copper foil grounding shielding layer (61) of a secondary PCB coil, a secondary PCB coil (40), and a bottom layer PCB (20).

5. The high-voltage isolation detection alarm device according to claim 4, wherein: The primary PCB coil (50) is spirally wound from outside to inside, and at the end of the inner coil, the primary PCB coil is connected to the primary PCB coil grounding shielding layer (60) through a metallized via hole (70); the primary PCB coil grounding shielding layer (60) is a large-area copper foil grounding shielding layer; The secondary PCB coil (40) is spirally wound from outside to inside, and at the end of the inner coil, the secondary PCB coil is connected to the secondary PCB coil grounding shielding layer (61) through a second metallized via hole (71); the secondary PCB coil grounding shielding layer (61) is a large-area copper foil grounding shielding layer.

6. The high-voltage isolation detection alarm device according to any one of claims 1 to 5, wherein: The voltage sampling module includes a high-voltage sampling voltage division circuit; The signal processing module comprises a low-pass filter circuit, a program-controlled preamplifier circuit and a program-controlled attenuation resistor array; the low-pass filter network circuit filters out the noise and interference in the sampling signal output by the high-voltage sampling voltage dividing circuit, and feeds the low-pass filtered signal into the program-controlled preamplifier circuit; the program-controlled preamplifier circuit is controlled by the MCU control circuit to adjust the gain resistor of the program-controlled amplifier circuit; the output of the program-controlled preamplifier circuit is fed into the program-controlled attenuation resistor array; the program-controlled attenuation resistor array is adjusted by the MCU control circuit to adjust the resistance voltage dividing ratio of the program-controlled attenuation resistor array, and further attenuates and adjusts the collected voltage signal. The alarm module comprises an LED alarm triggered by the trigger control circuit and a relay control alarm circuit.

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