CN-122013258-A - Cell voltage monitoring system and method for electrolytic cell

CN122013258ACN 122013258 ACN122013258 ACN 122013258ACN-122013258-A

Abstract

The invention discloses a cell voltage monitoring system and method for an electrolytic tank, relates to the technical field of monitoring of hydrogen production equipment by using electrolytic water, and solves the technical problems of low cell voltage measurement precision, weak anti-interference capability, poor expansibility and insufficient reliability in the high common-mode voltage and strong electromagnetic interference environment in the prior art. The system comprises an upper computer, a communication board and a collection group, wherein a layered distributed communication topology of a first-class star-shaped daisy chain and a second-class daisy chain is adopted, the collection group realizes high-voltage photoelectric isolation collection through optocoupler switching, differential conditioning and an independent ADC architecture, and the communication board integrates an isolation protection and DMA scheduling mechanism. The invention realizes high-precision in-situ automatic measurement of the voltages of multiple cells under high common-mode voltage.

Inventors

LI JINXING
LI WENQIANG
XIE SHUNDONG
LI YIYANG
ZHANG JIANSUO
LI GUIZHEN
ZHANG MINGRUI
JI JINXU
HAN CHAO
ZHAO XIAOHAN
WANG XIA
YU HONGYING

Assignees

天津市大陆制氢设备有限公司

Dates

Publication Date: 20260512
Application Date: 20260123

Claims (9)

1. The cell voltage monitoring system of the electrolytic cell is characterized by comprising an upper computer, a communication board and a collection group, wherein the communication board is upwards connected with the upper computer and downwards connected with the collection group through an RS-485 bus; the upper computer is used for parameter configuration, instruction issuing and data visual monitoring; The communication board is used as a central host and a Modbus gateway, an RS-485 isolation circuit, TVS anti-surge protection and magnetic isolation transceiver are integrated, and an internal main control chip of the communication board realizes real-time transfer and protocol conversion of data by executing an upward response upper computer task and a downward polling acquisition group task in parallel; The acquisition group is formed by physically dividing a plurality of acquisition boards, and each acquisition board acquires voltage signals of the electrolysis cell in real time through optocoupler switching, differential conditioning and an independent ADC architecture; the communication boards and the acquisition groups adopt hierarchical communication topology, the primary network is a star-shaped framework taking the communication boards as the center and is connected with the acquisition groups, and the secondary network is a daisy chain cascade framework among the acquisition boards in the groups.
2. The system for monitoring cell voltage of an electrolytic cell according to claim 1, wherein the communication board adopts a DMA scheduling mechanism, executes lower computer active polling when no upper computer instruction is available, and responds to an upper computer request preferentially when an upper computer interrupt instruction is detected.
3. The system for monitoring the cell voltage of the electrolytic cell according to claim 1, wherein the collecting group comprises a collecting main board and a plurality of collecting slave boards, the collecting main board and the collecting slave boards in the collecting group jointly form a distributed collecting system, the collecting main board and each collecting slave board are responsible for collecting the voltage of the cell and set a unique equipment address through a dial switch assembly, and the collecting main board is used for collecting data of each collecting slave board and uniformly packaging the collected group data.
4. A cell voltage monitoring system according to claim 3, characterized in that: The acquisition main board and the acquisition slave board respectively comprise an isolation power supply management module, an address detection module, a multiplexing switching module, a signal conditioning module, an ADC analog-to-digital conversion module, a main control module and a communication interface module, wherein the output end of the isolation power supply management module is respectively connected with the address detection module, the multiplexing switching module, the signal conditioning module, the ADC analog-to-digital conversion module, the main control module and the communication interface module, the main control module is respectively connected with the address detection module, the multiplexing switching module, the signal conditioning module, the ADC analog-to-digital conversion module and the communication interface module in a two-way manner, and the output end of the main control module is connected with the input end of the isolation power supply management module; The address detection module is provided with a dial switch assembly, and flexible setting and accurate detection of addresses and system addresses in the acquisition group are realized by manually configuring gears of the dial switch assembly so as to meet the address distinguishing and communication addressing requirements of multiple devices in the distributed acquisition system; The multiplexing switching module is internally integrated with an isolation optocoupler switching circuit, and the main control module is configured to gate the voltages at two ends of the target electrolysis cells to the signal conditioning module by controlling the on-off state of the isolation optocoupler switching circuit; The signal conditioning module adopts a differential amplifying circuit with high common mode rejection ratio and is used for stripping and amplifying differential mode voltage signals of the single cells from high common mode background voltage to obtain conditioned analog signals, and transmitting the conditioned analog signals to a next-stage circuit; the ADC module adopts an independent ADC chip with 16-bit resolution ratio to convert the conditioned analog signal into a digital signal; the isolation power supply management module adopts a multi-stage isolation design, and converts an external input power supply into a plurality of mutually independent power supply branches through the DC-DC and the isolation power supply management module, and respectively supplies power to the main control module, the signal conditioning module, the ADC module and the communication interface module independently; The master control module adopts master control chips of STM32 series microcontrollers, and the master control chips are integrated with independent watchdog modules and are used for monitoring the running state in real time and preventing program from being blocked to cause system halt; the communication interface module adopts an isolated transceiver chip to match a multistage surge protection network comprising a gas discharge tube, a piezoresistor and a TVS transient suppression diode array, and combines the miniaturization, high-speed transmission, antistatic discharge, electric fast transient pulse group and lightning surge interference capability; The acquisition main board also comprises a data summarizing module, wherein the data summarizing module is integrated in the main control circuit of the acquisition main board, the input end of the data summarizing module is connected with the acquisition slave boards through an inter-board communication interface and is used for receiving voltage digital signals transmitted by the acquisition slave boards, and the module splices and temporarily stores the received data of the acquisition slave boards and the data of the acquisition main board according to a preset physical address sequence.
5. The cell voltage monitoring system of claim 1, wherein the master control module of the acquisition board controls the switching of the optocoupler relay according to the time sequence of gating-stabilizing-sampling-disconnecting, so as to ensure the physical isolation between channels and the high signal-to-noise ratio of sampling.
6. A cell voltage monitoring method is characterized in that the monitoring method is realized based on the cell voltage monitoring system of any one of claims 1-5, and comprises the following steps: S1, initializing a system, after a communication board and an acquisition board are electrified, executing bottom hardware abstraction layer initialization, clock configuration, peripheral initialization and Modbus protocol stack parameter configuration, and starting a watchdog mechanism and a core task thread; S2, carrying out hierarchical polling collection, wherein a communication board is used as a host to periodically poll each collection group and collection boards in the groups through an RS-485 bus, and the collection board controls an optocoupler relay according to a gating-stabilizing-sampling-disconnecting time sequence, reads voltage data of each path of cells through an ADC chip and stores the voltage data temporarily; s3, data aggregation and uploading, wherein the acquisition board aggregates the processed voltage data to the group head end acquisition main board through the daisy chain architecture, and then transmits the voltage data to the communication board through the star architecture; And the communication board stores the data of each acquisition board into the shared buffer area, captures the query instruction of the upper computer, performs CRC16 check, encapsulates the query instruction into a Modbus-RTU protocol frame, and uploads the Modbus-RTU protocol frame to the upper computer to complete the cell voltage monitoring process at the current moment.
7. The cell voltage monitoring system according to claim 6, wherein in step S1, the peripheral initialization includes GPIO, UART, SPI, TIM and IWDG initialization, the core task thread includes a status indication task and a Modbus-RTU communication task, the Modbus protocol stack supports a Master host mode and a Slave Slave mode, the Master mode is used for a communication board to poll an acquisition board, and the Slave mode is used for the acquisition board to respond to a communication board instruction.
8. The method for monitoring cell voltage of an electrolytic cell according to claim 6, wherein in step S2, the specific implementation method of the hierarchical polling acquisition is as follows: The communication board polls each acquisition group in turn according to a preset period, the acquisition main board in each acquisition group is used as a Modbus master station in the group, 2-3 acquisition slave boards in the group are polled, and ADC data of the acquisition boards are subjected to double-window trimming mean value filtering and median filtering combination algorithm processing and then are calibrated in real time through compensation coefficients.
9. The method of claim 6, further comprising exception handling, wherein the system captures variable length data frames via serial port idle interrupts, and wherein the system uses a watchdog to monitor the operating status in real time, and wherein the automatic execution module is restarted when the monitoring communication is disconnected or the data is out of range.

Description

Cell voltage monitoring system and method for electrolytic cell Technical Field The invention relates to the technical field of monitoring of hydrogen production equipment by water electrolysis, relates to a voltage monitoring system, and in particular relates to a cell voltage monitoring system and method of an electrolytic cell. Background The cell voltage is a core operation parameter of the water electrolysis hydrogen production equipment, is directly related to the health state, hydrogen production efficiency and operation safety of the electrolytic cell, and has irreplaceable monitoring value in the industries of chemical industry, new energy, hydrogen energy storage and the like. In order to improve the hydrogen yield and reduce the unit hydrogen production cost, a design scheme for improving the current density and increasing the serial number of cells is commonly adopted for a large alkaline electrolytic cell (ALK) and a proton exchange membrane electrolytic cell (PEM), so that hundreds of volts of high common mode background voltage exists when the electrolytic cell operates, and the strong electromagnetic interference of an industrial site can further superimpose noise, so that weak differential mode voltage signals (millivolts) of single cells are seriously submerged, and great challenges are brought to accurate measurement. The existing cell voltage monitoring technology has the following key defects: the anti-interference capability is insufficient, the existing system mostly adopts a single isolation means (such as power isolation or communication isolation), a full-link high-voltage photoelectric isolation system is not formed, and high common mode voltage and electromagnetic interference are easy to invade a measuring loop through a power supply, a signal or a communication link, so that signal distortion is caused, and the crosstalk suppression ratio is generally lower than 40dB; the measurement precision is limited, namely, an 8-12-bit ADC chip is adopted, a targeted signal conditioning and temperature drift compensation mechanism is lacked, the measurement error is usually more than +/-1%, the high-precision monitoring requirement of 0.5% level cannot be met, and potential faults such as diaphragm breakdown, counter electrode and the like are difficult to identify in an early stage; the architecture has poor expansibility, namely a centralized acquisition architecture is adopted, all acquisition channels are concentrated in a single device, high-voltage wiring is required to be rearranged when monitoring points are newly added, the hardware change amount is large, the maintenance cost is high, and the whole monitoring system is paralyzed due to single device faults; The real-time performance and the reliability are unbalanced, namely, a single polling mechanism is adopted for communication, a priority-free scheduling strategy is adopted, the instruction response of an upper computer is delayed, a perfect fault isolation and automatic recovery mechanism is lacked, channel faults are easy to spread to the whole world, and the unattended operation requirement of an industrial field cannot be met. Although partial prior art attempts adopt a distributed architecture or a photoelectric isolation technology, deep fusion of a layered distributed architecture and high-voltage photoelectric isolation is not realized, wherein the distributed architecture does not optimize communication topology aiming at a high common mode environment, so that signal reflection and interference superposition are caused, the photoelectric isolation is only applied to a local module, full link isolation is not formed, and the interference problem cannot be fundamentally solved. Therefore, developing a monitoring system and method with high anti-interference capability, high precision, high expansibility and high reliability becomes a key for breaking through the bottleneck of the prior art. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides an electrolytic cell voltage monitoring system and method based on layered distributed architecture and high-voltage photoelectric isolation, which solve the problem of accurate monitoring under the environment of high common-mode voltage and strong electromagnetic interference and simultaneously consider expansibility, instantaneity and reliability through hardware architecture innovation and software cooperative scheduling. The invention solves the technical problems by adopting the following technical scheme: The cell voltage monitoring system of the electrolytic cell is characterized by comprising an upper computer, a communication board and a collection group, wherein the communication board is upwards connected with the upper computer and downwards connected with the collection group through an RS-485 bus; the upper computer is used for parameter configuration, instruction issuing and data visual monitoring; The communication bo