Reverse current detection device

Abstract

The invention discloses a reverse current detection device, which is applied to an alkaline water electrolytic tank connected with a direct-current power supply and comprises a state switching module, a data acquisition module and an upper computer, the state switching module is used for switching the working state of the alkaline water electrolytic tank; when the working state of the alkaline water electrolytic tank is normal operation, the direct-current power supply supplies power to the alkaline water electrolytic tank; and when the working state of the alkaline water electrolytic tank is that the alkaline water electrolytic tank stops running, the data acquisition module accelerates the discharge speed of the alkaline water electrolytic tank, so that the alkaline water electrolytic tank discharges to a preset safety voltage, and acquires the reverse current of the alkaline water electrolytic tank to be fed back to the upper computer for display. According to the invention, the high common-mode voltage interference of the alkaline water electrolyzer during operation is fundamentally eliminated, and the extreme requirement on the common-mode rejection ratio (CMRR) of a sensor for collecting reverse current is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alkaline water electrolyzer detection, and particularly to a reverse current detection device. BACKGROUND

[0002] The alkaline water electrolyzer is a core device in the large-scale electrolysis of water to produce hydrogen, and its working electric energy is supplied by an external direct current power supply to decompose water molecules to produce hydrogen. At the moment of system shutdown, the potential difference between the anode and the cathode, the electron (e-) path through the bipolar plate and the hydroxyl ion (OH-) path through the manifold will generate a reverse current. The reverse current will cause the positive shift of the cathode polarization potential, trigger the electrochemical corrosion of the cathode material and cause the passivation of the catalyst layer, and finally deteriorate the catalytic activity and service life of the electrode.

[0003] Since the working voltage of the alkaline water electrolyzer is usually several tens of volts or even thousands of volts, and the working current is usually several hundred or even tens of thousands of amperes, the reverse current is a very small current value generated at the moment of shutdown, and changes very quickly. To quickly capture and accurately measure the millivolt or ampere level change, the common mode rejection ratio CMRR requirement of the sensor is extremely high.

[0004] Therefore, there is an urgent need for a device that can detect the reverse current of the alkaline water electrolyzer to avoid the high common mode voltage interference on the reverse current sensor for collecting during the operation of the alkaline water electrolyzer. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a reverse current detection device which can avoid the high common mode voltage interference on the reverse current sensor for collecting during the operation of the alkaline water electrolyzer.

[0006] In order to solve the above problems, the present application is realized according to the following scheme: A reverse current detection device is provided, which is applied to an alkaline water electrolyzer connected with a direct current power supply, and comprises a state switching module, a data acquisition module and an upper computer. The state switching module is connected with the direct current power supply, the alkaline water electrolyzer and the data acquisition module, and the data acquisition module is connected with the alkaline water electrolyzer and the upper computer. The state switching module is used to switch the working state of the alkaline water electrolyzer. When the working state of the alkaline water electrolyzer is normal operation, the direct current power supply supplies power to the alkaline water electrolyzer. When the working state of the alkaline water electrolyzer is stop operation, the data acquisition module accelerates the discharging speed of the alkaline water electrolyzer, discharges the alkaline water electrolyzer to a preset safety voltage, and acquires the reverse current of the alkaline water electrolyzer to feed back to the upper computer for display.

[0007] Compared with the prior art, the reverse current detection device has the following advantages: the alkaline water electrolysis tank is disconnected from the data acquisition module for detecting the reverse current by the state switching module during normal operation, and the loop formed by the direct current power supply and the alkaline water electrolysis tank is disconnected at the moment when the alkaline water electrolysis tank stops, and the loop of the alkaline water electrolysis tank and the data acquisition module for detecting the reverse current is automatically connected, which fundamentally eliminates the high common-mode voltage interference of the alkaline water electrolysis tank during operation and greatly reduces the extreme requirement for the common-mode rejection ratio (CMRR) of the reverse current sensor.

[0008] Optionally, the state switching module comprises an interlocked first switch and a second switch, the first switch is connected with the direct current power supply and the alkaline water electrolysis tank, and the second switch is connected with the data acquisition module.

[0009] Optionally, the first switch and the second switch are both field effect tubes.

[0010] Optionally, the first switch and the second switch are both insulated gate bipolar transistors.

[0011] Optionally, the data acquisition module comprises a safety unit, an acquisition unit and a processing unit, the safety unit is connected with the state switching module, the acquisition unit is connected with the processing unit, the alkaline water electrolysis tank and the state switching module, and the processing unit is connected with the upper computer.

[0012] Optionally, the safety unit comprises a discharge resistor, and the discharge resistor is connected with the state switching module.

[0013] Optionally, the acquisition unit comprises a direct current sensor, and the direct current sensor is connected with the processing unit, the alkaline water electrolysis tank and the state switching module.

[0014] Optionally, the processing unit comprises a transmitter and a PLC, the transmitter is connected with the PLC and the acquisition unit, and the PLC is connected with the upper computer.

[0015] Optionally, the upper computer comprises a processor and a memory, and the memory stores at least one instruction, at least one program, a code set or an instruction set, the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 It is a structural block diagram of the detection device of the present application; Fig. 2 It is a structural schematic diagram of the detection device of the present application; The reference signs are explained as follows: 1, state switching module; 101, first switch; 102, second switch; 2, data acquisition module; 201, safety unit; 202, acquisition unit; 203, processing unit; 2031, transmitter; 2032, PLC; 3, upper computer; 4, DC power supply; 5, alkaline water electrolyzer. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present application will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0018] In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present application. It should be appreciated that the present application can be practiced in a variety of ways, and that the following examples are not limiting.

[0019] Reference Signs List Figs. 1-2 As shown in the drawings, the reverse current detection device of the present application is applied to the alkaline water electrolyzer 5 connected with the DC power supply 4, and comprises a state switching module 1, a data acquisition module 2 and an upper computer 3. The state switching module 1 is connected with the DC power supply 4, the alkaline water electrolyzer 5 and the data acquisition module 2, and the data acquisition module 2 is connected with the alkaline water electrolyzer 5 and the upper computer 3. The state switching module 1 is used to switch the working state of the alkaline water electrolyzer 5. When the working state of the alkaline water electrolyzer 5 is normal operation, the DC power supply 4 supplies power to the alkaline water electrolyzer 5. When the working state of the alkaline water electrolyzer 5 is stop operation, the data acquisition module 2 accelerates the discharging speed of the alkaline water electrolyzer 5, discharges the alkaline water electrolyzer 5 to a preset safety voltage, and acquires the reverse current of the alkaline water electrolyzer 5 to feed back to the upper computer 3 for display.

[0020] In one embodiment of the present application, the state switching module 1 comprises interlocked first switch 101 and second switch 102, the first switch 101 is connected with the direct current power supply 4 and the alkaline water electrolyzer 5, and the second switch 102 is connected with the data acquisition module 2; the present application ensures that the first switch 101 is closed and the second switch 102 is opened when the alkaline water electrolyzer 5 is running normally, so as to realize the physical isolation between the alkaline water electrolyzer 5 and the data acquisition module 2; when the alkaline water electrolyzer 5 stops running, the first switch 101 is opened and the second switch 102 is closed, so that the data acquisition module 2 can quickly acquire the reverse current of the alkaline water electrolyzer 5 at the moment when the alkaline water electrolyzer 5 stops running.

[0021] In one embodiment of the present application, the first switch 101 and the second switch 102 are both field effect tubes; or the first switch 101 and the second switch 102 are both insulated gate bipolar transistors, which can realize the rapid switching of the first switch 101 and the second switch 102.

[0022] In one embodiment of the present application, the data acquisition module 2 comprises a safety unit 201, an acquisition unit 202 and a processing unit 203, the safety unit 201 is connected with the state switching module 1, the acquisition unit 202 is connected with the processing unit 203, the alkaline water electrolyzer 5 and the state switching module 1, and the processing unit 203 is connected with the upper computer 3.

[0023] In one embodiment of the present application, the safety unit 201 comprises a discharge resistor; the discharge resistor is connected with the state switching module 1; in the actual application process, the resistance value of the discharge resistor should be balanced between the rapid and safe discharge and the reduction of power loss, that is, the resistance value thereof should be low enough to make the discharge time short and ensure that the alkaline water electrolyzer 5 can be discharged to the safe voltage as soon as possible; but the resistance value thereof should also be high enough to reduce the power loss of the resistor, prevent the resistor from sharply heating to affect the surrounding equipment, and limit the size of the reverse current.

[0024] In an embodiment of the present application, the resistance value of the discharge resistor is determined, including: determining the initial working voltage before the alkaline water electrolyzer 5 stops running, the equivalent capacitance value of the alkaline water electrolyzer 5, the safe discharge voltage, the discharge time constant, and the discharge time, etc. In order to cover various stop working conditions, the initial working voltage before stopping running is the highest working voltage Vmax, the equivalent capacitance value is C, the safe discharge voltage is Vsafe, and according to the safety specification, the limit value of the direct current safe voltage that the human body can continuously contact in a dry place under general environment is 50V, so the safe discharge voltage Vsafe is generally selected to be less than or equal to 50V. A smaller value can be selected according to the severity of the environment for extreme environments such as humidity or airtightness. The discharge time constant is τ=RC, which represents the time required for the voltage to drop to the initial value. The discharge time is t, which is usually 5-15 minutes according to industry practice, and 5 minutes is selected under normal circumstances, which can quickly reach a safe state and will not require too high power for the resistor, achieving a balance between safety and cost efficiency; and the resistance value calculation formula of the discharge resistor is as follows: R=-t / (C*ln(Vsafe / Vmax)) Wherein, R is the resistance value of the discharge resistor, Vmax is the initial working voltage, C is the equivalent capacitance value, Vsafe is the safe discharge voltage, and t is the discharge time.

[0025] In engineering practice, it is generally believed that after 5τ, the discharge process is essentially completed, and the remaining voltage is less than 1% of the initial working voltage, so the discharge time is usually 5τ. According to the formula: R≈t / 5C, the discharge time t is substituted to calculate the approximate value of the resistance value R of the discharge resistor.

[0026] According to the formula P=Vmax 2 / R, the maximum instantaneous power Pmax of the discharge resistor is calculated, and finally the resistance value of the discharge resistor is the resistance value calculated by 1.5 times or 2 times the maximum instantaneous power (1.5Pmax / 2Pmax) (Vmax 2 / 1.5Pmax or Vmax 2 / 2Pmax).

[0027] By determining the resistance value of the discharge resistor, the alkaline water electrolyzer 5 can be discharged to a safe voltage as soon as possible at the moment of shutdown, avoiding the risk of electric shock, and also reducing the power loss of the resistor and suppressing the size of the reverse current, avoiding the impact of the reverse current on the alkaline water electrolyzer 5.

[0028] In an embodiment of the present application, the discharge resistor is cooled by air cooling or water cooling.

[0029] In one embodiment of the present invention, the acquisition unit 202 includes a DC sensor; the DC sensor is connected to the processing unit 203, the alkaline water electrolyzer 5, and the state switching module 1; the DC sensor can be an isolated sensor with fast response and high accuracy, such as a zero-flux Hall current sensor, to ensure the measurement accuracy and safety of the reverse current of the alkaline water electrolyzer 5 at the moment of shutdown.

[0030] In one embodiment of the present invention, the processing unit 203 includes a transmitter 2031 and a PLC 2032; the transmitter 2031 is connected to the PLC 2032 and the acquisition unit 202, and the PLC 2032 is connected to the host computer 3; wherein, the transmitter 2031 is used to convert the reverse current signal acquired by the DC sensor into a 4mA-20mA current signal, and the PLC 2032 is used to upload the 4mA-20mA current signal transmitted from the transmitter 2031 to the host computer 3 for display and storage.

[0031] Fig. 2 The first switch 101 and the second switch 102 shown are field-effect transistors. The following will use... Fig. 2 The connection relationship and working principle between the detection device of the present invention, the DC power supply 4, and the alkaline water electrolysis cell 5 are explained in detail using the following example: The positive terminal of the DC power supply 4 is connected to the drain of the first switch 101. The positive terminal of the alkaline water electrolysis cell 5 is connected to the source of the first switch 101 and the discharge resistor. The negative terminal of the alkaline water electrolysis cell 5 is connected to the negative terminal of the DC power supply 4 and the DC sensor. The drain of the second switch 102 is connected to the discharge resistor. The source of the second switch 102 is connected to the DC sensor. The DC sensor is connected to the host computer 3 in sequence through the transmitter 2031 and the PLC 2032.

[0032] When a start signal is received, the first switch 101 closes and the second switch 102 opens. The DC power supply 4 provides the current required for normal operation of the alkaline water electrolysis cell 5. When the alkaline water electrolysis cell 5 suddenly stops, the first switch 101 opens and the second switch 102 closes. The reverse current is transmitted to the DC sensor through the discharge resistor and the second switch 102 so that the reverse current can be collected in real time by the DC sensor. The transmitter 2031 converts the reverse current collected by the DC sensor into a current signal that can be recognized by the PLC 2032 and transmits it to the host computer 3 for real-time display and storage.

[0033] The host computer 3 of the present invention includes a processor and a memory. The memory stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor.

[0034] The processor can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc.

[0035] The memory can be used to store the computer programs or modules, the processor runs or executes the computer programs or modules stored in the memory, and calls the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required by a function, etc.; the data storage area can store data created according to the use of the mobile phone, etc. In addition, the memory can include a high-speed random access memory, and can also include a nonvolatile memory, for example, a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one disk storage device, a flash memory device, or other volatile solid-state memory device.

[0036] The above are only the preferred embodiments of the present application, and are not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A reverse current detection device, applied to an alkaline water electrolysis cell connected to a DC power supply, characterized in that, include: Status switching module, data acquisition module and host computer; The state switching module is connected to the DC power supply, the alkaline water electrolysis cell, and the data acquisition module. The data acquisition module is connected to the alkaline water electrolysis cell and the host computer. The state switching module is used to switch the working state of the alkaline water electrolyzer; When the alkaline water electrolyzer is in normal operation, the DC power supply supplies power to the alkaline water electrolyzer. When the alkaline water electrolyzer is in a stopped operating state, the data acquisition module accelerates the discharge speed of the alkaline water electrolyzer, causing it to discharge to a preset safe voltage, and collects the reverse current of the alkaline water electrolyzer to feed back to the host computer for display.

2. The reverse current detection device according to claim 1, characterized in that, The state switching module includes an interlocked first switch and a second switch. The first switch is connected to the DC power supply and the alkaline water electrolysis cell, and the second switch is connected to the data acquisition module.

3. The reverse current detection device according to claim 2, characterized in that, Both the first switch and the second switch are field-effect transistors.

4. The reverse current detection device according to claim 2, characterized in that, Both the first switch and the second switch are insulated gate bipolar transistors.

5. A reverse current detection device according to claim 1, characterized in that, The data acquisition module includes a security unit, an acquisition unit, and a processing unit. The security unit is connected to the state switching module, the acquisition unit is connected to the processing unit, the alkaline water electrolysis cell, and the state switching module, and the processing unit is connected to the host computer.

6. A reverse current detection device according to claim 5, characterized in that, The safety unit includes a discharge resistor; the discharge resistor is connected to the state switching module.

7. A reverse current detection device according to claim 5, characterized in that, The acquisition unit includes a DC sensor; the DC sensor is connected to the processing unit, the alkaline water electrolysis cell, and the state switching module.

8. A reverse current detection device according to claim 5, characterized in that, The processing unit includes a transmitter and a PLC; the transmitter is connected to the PLC and the acquisition unit, and the PLC is connected to the host computer.

9. A reverse current detection device according to claim 1, characterized in that, The host computer includes a processor and a memory. The memory stores at least one instruction, at least one program, code set, or instruction set. The processor loads and executes at least one instruction, at least one program, code set, or instruction set.

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