CN113823817A - Impedance measurement and control device and method for vehicle-mounted fuel cell - Google Patents

Impedance measurement and control device and method for vehicle-mounted fuel cell Download PDF

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CN113823817A
CN113823817A CN202111272264.9A CN202111272264A CN113823817A CN 113823817 A CN113823817 A CN 113823817A CN 202111272264 A CN202111272264 A CN 202111272264A CN 113823817 A CN113823817 A CN 113823817A
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fuel cell
current
voltage
galvanic pile
inspection device
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赵兴旺
盛有冬
李飞强
张国强
方川
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Beijing Sinohytec Co Ltd
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Beijing Sinohytec Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04992—Processes for controlling fuel cells or fuel cell systems characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04537—Electric variables
    • H01M8/04544—Voltage
    • H01M8/04552—Voltage of the individual fuel cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04537—Electric variables
    • H01M8/04574—Current
    • H01M8/04582—Current of the individual fuel cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04537—Electric variables
    • H01M8/04634—Other electric variables, e.g. resistance or impedance
    • H01M8/04641—Other electric variables, e.g. resistance or impedance of the individual fuel cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04746—Pressure; Flow
    • H01M8/04753—Pressure; Flow of fuel cell reactants
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

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  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Fuel Cell (AREA)
  • Automation & Control Theory (AREA)
  • Artificial Intelligence (AREA)
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  • Evolutionary Computation (AREA)
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Abstract

The invention provides an impedance measurement and control device and method for a vehicle-mounted fuel cell, belongs to the technical field of fuel cell impedance measurement, and solves the problem that the prior art cannot effectively measure the alternating current impedance of a single cell and control the operation of a galvanic pile. The device comprises an electric pile, a DC-DC converter, a current sensor, a voltage inspection device and a controller. The DC-DC converter and the voltage inspection device are connected through a signal synchronization line; the current sensor is arranged inside the DC-DC converter; each electrode of the voltage inspection device is respectively connected with the output end of a single battery of the electric pile. And the controller is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal to the galvanic pile, starting the voltage inspection device after the numerical value of the current sensor is stable, combining the voltage of each single battery in the galvanic pile with the measured current at the same moment to obtain the alternating current impedance of each single battery according to the fed back voltage of each single battery, and controlling the operation of the galvanic pile. The functions of measuring and controlling the impedance of the single-chip cell of the electric pile are realized.

Description

Impedance measurement and control device and method for vehicle-mounted fuel cell
Technical Field
The invention relates to the technical field of fuel cell impedance measurement, in particular to an impedance measurement and control device of a vehicle-mounted fuel cell.
Background
The hydrogen energy fuel cell automobile is a new energy automobile with wide development prospect, and has the advantages of short hydrogenation time, long driving range and the like. The vehicle-mounted fuel cell system generally comprises an electric pile and peripheral hydrogen, air and cooling subsystems, wherein the electric pile comprises a proton exchange membrane, a catalyst layer, a gas diffusion layer, a bipolar plate and the like, and because the theoretical voltage of 1 cell is 1.23V, the high-power output is generally realized by connecting hundreds of cells in series.
Ac impedance is a method of monitoring the internal state of a fuel cell, and is generally implemented by a DC/DC device, but it can only collect impedance information at the level of the whole stack. For example, patent CN105699902A proposes an impedance measuring apparatus and method for fuel cell diagnosis, but only calculates the overall impedance of the stack. The electric pile is actually formed by a plurality of single batteries, and different single batteries have the problem of inconsistency of temperature, gas supply state and even current density due to different positions in the electric pile, so that the impedance of the single batteries is inconsistent. The reliability of the stack depends on the worst performing cell in the stack.
Patent CN111244505A proposes a method for monitoring single-chip ac impedance, in which current collection and single-chip voltage collection are implemented by the same device, but in the product integration process, in order to facilitate independent development of components, the current collection function and the single-chip voltage collection are implemented by different hardware, and in the process of implementing the ac impedance function, the problem of inaccurate impedance result due to asynchronous voltage and current signal collection may be encountered.
Disclosure of Invention
The embodiment of the invention aims to provide an impedance measurement and control device of a vehicle-mounted fuel cell, which is used for solving the problem that the prior art can not effectively measure the alternating current impedance of a single cell and control the operation of a galvanic pile.
On one hand, the embodiment of the invention provides an impedance measurement and control device of a vehicle-mounted fuel cell, which is characterized by comprising an electric pile, a DC-DC converter, a current sensor, a voltage inspection device and a controller; wherein the content of the first and second substances,
the DC-DC converter and the voltage inspection device are connected through a signal synchronization line; the current sensor is arranged inside the DC-DC converter; each electrode of the voltage inspection device is respectively connected with the output end of a single battery of the electric pile; the output ends of the current sensor and the voltage inspection device are respectively connected with the input end of the controller, and the control ends are respectively connected with the output end of the controller;
the controller is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal with preset frequency to the galvanic pile, starting the voltage inspection device after the value measured by the current sensor is stable, and controlling the operation of the galvanic pile by obtaining the alternating current impedance of each single battery according to the voltage of each single battery in the galvanic pile at the same feedback moment and the current measured by the current sensor.
The beneficial effects of the above technical scheme are as follows: the impedance measurement and control device of the fuel cell is provided, a synchronization mechanism of a signal synchronization line is combined with the alternating current impedance measurement and control structure, coupling design of impedance measurement and control functions is realized by combining different hardware with measurement and control programs, modularization, interchangeability and independent development of different hardware are facilitated, and flexibility and convenience are achieved.
Based on a further improvement of the above apparatus, the controller further comprises:
the data acquisition unit is used for acquiring real-time data information in output signals of the current sensor and the voltage inspection device and sending the real-time data information to the data processing and control unit; the data information comprises the amplitude or effective value of the output current of the electric pile, and the amplitude or effective value of the voltage of each single battery;
the data processing and control unit is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal with preset frequency to the galvanic pile, starting the voltage inspection device after the value measured by the current sensor is stable, combining the current amplitude with the voltage amplitude of each single battery at the same moment according to feedback to obtain the alternating current impedance of each single battery, and controlling the operation of the galvanic pile;
and the execution mechanism is used for changing the running state of the electric pile according to the control of the data processing unit.
The beneficial effects of the above further improved scheme are: the structure of the controller is limited, and the controller is used for realizing the collection of the state information of the fuel cell and the measurement and control of the impedance.
Further, the actuator further comprises:
the reactor gas control equipment is used for controlling the flow and pressure of reactor hydrogen and air; the output end of the controller is connected with the gas inlet of the galvanic pile, and the control end of the controller is connected with the output end of the controller;
a coolant temperature adjusting device for controlling a temperature of the cooling liquid fed into the stack; the control end of the controller is connected with the output end of the controller; and a coolant inlet of the cell stack is connected to a coolant outlet thereof through the coolant temperature adjusting apparatus.
The beneficial effects of the above further improved scheme are: the composition of the actuator is defined so that control of the flow rate of the input gas, the pressure and the water temperature of the coolant at the time of starting or shutting down the vehicle, removal of residual oxygen inside the fuel cell stack, and rapid heating of the fuel cell stack at the time of cold start of the vehicle can be performed to improve the activity of the fuel cell.
Furthermore, the actuating mechanism also comprises a controllable switch I and a controllable switch II; wherein the content of the first and second substances,
the controllable switch I is used for controlling the starting of the DC-DC converter, and the output end of the controllable switch I is connected with the control end of the DC-DC converter;
and the controllable switch II is used for controlling the starting of the voltage inspection device, and the output end of the controllable switch II is connected with the control end of the voltage inspection device.
The beneficial effects of the above further improved scheme are: the controllable switch I and the controllable switch II are added, so that the signal acquisition time can be strictly controlled, and the measurement and control process is more accurate.
Further, the data processing and control unit executes the following program:
acquiring real-time electric pile output current and judging whether the fuel cell normally operates or not; if the fuel cell is abnormally operated, adjusting the operation parameters of the fuel cell until the fuel cell is normally operated; the operation parameters comprise at least one of flow rate, pressure and water temperature of reactor entering cooling liquid of reactor entering hydrogen and air;
starting the DC-DC converter and sending an alternating current excitation signal with preset frequency to the galvanic pile;
monitoring the value measured by the current sensor, and starting the voltage inspection device after the value measured by the current sensor is stable;
obtaining the current measured by the current sensor at the same moment after the voltage inspection device is started and the voltage of each single battery measured by the voltage inspection device;
obtaining the amplitude and the phase of the alternating current impedance of each single battery under the preset frequency according to the voltage and the current;
and adjusting the operation parameters of the fuel cell according to the obtained amplitude and phase of the alternating current impedance of each single cell, and controlling the operation of the electric pile.
The beneficial effects of the above further improved scheme are: the execution program of the controller is limited, and the alternating current impedance measurement function, the coordination control function and the synchronization function can be realized.
Further, the controller executes the following program to determine whether the fuel cell is operating normally:
acquiring real-time output current of the galvanic pile in a preset time period;
determining the effective value and the maximum variation of the real-time output current;
judging whether the effective value of the real-time output current is within a preset range or not, and simultaneously, meeting the condition that the maximum variation does not exceed a preset threshold; if yes, judging that the fuel cell normally operates; otherwise, adjusting the operation parameters of the fuel cell, including the flow and pressure of the hydrogen and air in the stack and the water temperature of the cooling liquid in the stack, and judging again until the fuel cell is judged to normally operate.
The beneficial effects of the above further improved scheme are: the method for judging whether the fuel cell normally operates is limited, whether the effective value of the output current is in a preset range can be strictly judged through the real-time output current of the galvanic pile, and meanwhile the maximum variation is not more than a preset threshold. In fact, the accurate alternating current impedance of the fuel cell cannot be obtained by using the data of the fuel cell in abnormal operation, the judgment of a user is interfered, and the scheme lays a foundation for subsequent accurate data acquisition and fault correction (such as temperature regulation and control) of the fuel cell.
Further, the firstiAmplitude of AC impedance of single-chip batteryZ fi And phase (Z fi ) Is composed of
Z fi =ΔV i /ΔI
phase(Z fi )=β 2 -β i1
In the formula,. DELTA.VIs as followsiMagnitude of voltage vector, Delta, of individual monolithic cellsIIs the magnitude of the current vector and,β 2 is the phase angle of the current vector,β i1is as followsiThe phase angle of the voltage vector of the individual monolithic cells,i=1,…,n，nis the number of single cells in the stack.
The beneficial effects of the above further improved scheme are: the method for measuring the amplitude and the phase of the alternating current impedance of each single battery is defined. And a foundation is laid for the subsequent control of the operation of the galvanic pile.
Further, the controller executes the following program to control the operation of the electric pile:
obtaining the amplitude of the AC impedance of each single batteryZ fi And phase (Z fi ) And the magnitude of the voltage vector of each monolithic cellV；
Each of the amplitudes ΔVRespectively, are compared with a preset value one if the amplitude value deltaVIf the number of the single-chip batteries smaller than or equal to the preset value I exceeds a rated value, judging that the input gas of the galvanic pile is insufficient, and controlling the flow and pressure of the hydrogen and air entering the galvanic pile to increase, otherwise, maintaining the flow and pressure of the hydrogen and air entering the galvanic pile unchanged;
each of the amplitude valuesZ fi Comparing with the second preset value, if the amplitude value is larger than the second preset valueZ fi If the number of the single-chip batteries greater than or equal to the second preset value exceeds a rated value, the proton exchange membrane of the galvanic pile is judged to be in a dry state, the cooling liquid temperature regulating equipment is controlled to reduce the water temperature of the cooling liquid entering the galvanic pile, and if not, the current water temperature is maintained unchanged;
according to said phase (Z fi ) Determining the time from the next starting time of the voltage inspection device to the signal acquisition timet
t=∑phase(Z fi )/（2nπf）+t 0
In the formula (I), the compound is shown in the specification,t 0the time from the moment of starting the voltage inspection device to the moment of signal acquisition,fthe frequency of the ac excitation signal.
The beneficial effects of the above further improved scheme are: the method for controlling the operation of the galvanic pile according to the impedance of the single-chip battery is limited, so that the time from the moment of starting the voltage inspection device to the moment of signal acquisition can be more accurately controlled during low-temperature cold starttAnd the accuracy of the collected data is ensured.
Further, the data processing and control unit is provided with a display module; and the number of the first and second electrodes,
the display screen of the display module displays the integral internal resistance of the fuel cell stackZ f And the internal resistance of each single cell in the stackZ fi ；
The overall internal resistance of the fuel cell stackZ f Obtained by the following formula
Z f= ∑Z fi
In the formula (I), the compound is shown in the specification,t 0the time from the moment of starting the voltage inspection device to the moment of signal acquisition,fis the frequency of the ac excitation signal,i=1,…,n，nis the number of single cells in the stack.
The beneficial effects of the above further improved scheme are: the display module and the display content are limited, the fuel cell stack is composed of a plurality of single cells, different single cells have inconsistency problems in temperature, gas supply state and even current density of each single cell due to different positions of the single cells in the stack, and the problem of inconsistent impedance of the single cells is caused. The reliability of the stack depends on the state of the worst performing cell in the stack. The impedance of the single battery can provide the most accurate data for the fault diagnosis of the fuel cell.
On the other hand, an embodiment of the present invention provides an impedance measurement and control method for a vehicle-mounted fuel cell corresponding to the apparatus, including the following steps:
when the galvanic pile normally operates, starting the DC-DC converter, and sending an alternating current excitation signal with preset frequency to the galvanic pile;
starting the voltage inspection device after the value measured by the current sensor is stable;
and according to the voltage of each single battery in the galvanic pile at the same time and the current measured by the current sensor, the alternating current impedance of each single battery is obtained, and the galvanic pile is controlled to operate.
The beneficial effect who adopts above-mentioned scheme is: the impedance measurement and control method of the fuel cell is provided, a synchronization mechanism of a signal synchronization line is combined with the alternating current impedance measurement and control structure, coupling design of impedance measurement and control functions is achieved by means of a measurement and control program, and the method is flexible and convenient.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the disclosure, nor is it intended to be used to limit the scope of the disclosure.
Drawings
The foregoing and other objects, features and advantages of the disclosure will be apparent from the following more particular descriptions of exemplary embodiments of the disclosure as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the disclosure.
FIG. 1 is a schematic diagram showing the components of an impedance measurement and control device in embodiment 1;
FIG. 2 is a schematic circuit diagram of the impedance measurement and control device in the embodiment 1;
fig. 3 shows a schematic composition diagram of the impedance measurement and control device in embodiment 2.
Reference numerals:
41-end plate of the stack; 42-an insulating plate; 43-a current collector plate; 44-a monolithic cell; a 10-DC-DC converter; a current sensor inside the 11-DC-DC converter; 20-signal synchronization line; 30-a controller; 50-voltage inspection device.
Detailed Description
Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The term "include" and variations thereof as used herein is meant to be inclusive in an open-ended manner, i.e., "including but not limited to". Unless specifically stated otherwise, the term "or" means "and/or". The term "based on" means "based at least in part on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first," "second," and the like may refer to different or the same object. Other explicit and implicit definitions are also possible below.
Example 1
The invention discloses an impedance measurement and control device of a vehicle-mounted fuel cell, which comprises an electric pile, a DC-DC converter, a current sensor, a voltage inspection device and a controller, and is shown in figures 1-2.
The DC-DC converter and the voltage inspection device are connected through a signal synchronization line; the current sensor is arranged inside the DC-DC converter; each electrode of the voltage inspection device is respectively connected with the output end of a single battery of the electric pile; and the output ends of the current sensor and the voltage inspection device are respectively connected with the input end of the controller, and the control ends are respectively connected with the output end of the controller.
The signal synchronization line is used for acquiring a voltage signal of the single battery by the voltage inspection device and acquiring a trigger synchronization or clock synchronization function of a current signal by the DC-DC converter when the alternating current impedance function is started. Alternatively, an existing signal synchronization line, such as the signal synchronization line in patent CN201910237668.0, etc., may be used.
And the current sensor is used for acquiring the output current (signal) of the galvanic pile.
And the voltage inspection device is used for collecting the voltage (signal) of each single battery in the electric pile after starting.
And the controller is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal with preset frequency to the galvanic pile, starting the voltage inspection device after the value measured by the current sensor is stable, and controlling the operation of the galvanic pile by combining the voltage of each single battery in the galvanic pile with the current measured by the current sensor at the same time according to the feedback to obtain the alternating current impedance of each single battery.
Alternatively, in the program executed by the controller, the above-mentioned criterion for judging the normal operation of the stack may be the output current, voltage or power of the stack. And comparing the output current, voltage or power of the galvanic pile with a preset range of normal operation calibrated in advance, if the output current, voltage or power of the galvanic pile falls into the preset range, judging that the galvanic pile normally operates, and otherwise, abnormally operating.
Optionally, the controller executes a program in which the preset frequency is in the range of 0.1-10 kHz, preferably, the high frequency may be 1 kHz, and the low frequency may be 50 Hz. Illustratively, the preset frequency ac excitation signal may be a 5A sinusoidal ac excitation.
Optionally, in the program executed by the controller, the criterion for determining that the value measured by the current sensor is stable may be that the maximum current and the minimum current do not exceed a preset range, or that the effective value is within a preset range.
Alternatively, the controller may obtain the ac impedance of the monolithic battery by the following formulaZOr obtaining the amplitude and phase of the AC impedance of the monolithic battery by the method described in example 2
Z=U/I （1）
In the formula (I), the compound is shown in the specification,Ufor voltage inspection device to collectiThe voltage vector of the individual single-chip cells,Ia current vector collected for the current sensor.
Optionally, the operation of the stack is controlled, including controlling the flow rate and pressure of the stack hydrogen and air, the water temperature of the stack coolant, and the signal acquisition timing (or time), and those skilled in the art will understand that the operation is not particularly limited herein. For example, the amplitude or phase of the ac impedance may be compared with a plurality of thresholds, and then adjustment information of the flow rate, pressure, water temperature of the reactor coolant, and signal acquisition time of the reactor hydrogen and air may be obtained.
Compared with the prior art, the embodiment provides a novel impedance measurement and control device for a fuel cell, a synchronization mechanism of a signal synchronization line is combined with the alternating current impedance measurement and control structure, the coupling design of the impedance measurement function is realized by means of different hardware, the modularization, interchangeability and independent development of different hardware are facilitated, and the device is flexible and convenient.
Example 2
The improvement is carried out on the basis of the embodiment 1, and the controller further comprises a data acquisition unit, a data processing and control unit and an execution mechanism which are connected in sequence, as shown in fig. 3. The input end of the data acquisition unit is respectively connected with the output ends of the current sensor and the voltage inspection device; the output end of the actuating mechanism is respectively connected with the DC-DC converter, the voltage inspection device and the control end of the running state of the galvanic pile. Specifically, the control end of the operation state of the electric pile comprises the air hydrogen, the hydrogen input end, the cooling liquid inlet and the like of the electric pile.
The data acquisition unit is used for acquiring real-time data information in output signals of the current sensor and the voltage inspection device and sending the real-time data information to the data processing and control unit; the data information comprises the amplitude or effective value of the output current of the electric pile, and the amplitude or effective value of the voltage of each single battery.
And the data processing and control unit is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal with preset frequency to the galvanic pile, starting the voltage inspection device after the value measured by the current sensor is stable, combining the current amplitude with the voltage amplitude of each single battery at the same moment according to the feedback to obtain the alternating current impedance of each single battery, and controlling the operation of the galvanic pile.
And the executing mechanism is used for starting the DC-DC converter and the voltage inspection device or changing the running state of the galvanic pile according to the control of the data processing unit.
Preferably, the actuator further comprises a reactor gas control device, a coolant temperature adjusting device, and a controllable switch I and a controllable switch II. The output end of the reactor-entering gas control equipment is connected with a gas inlet of the galvanic pile, and the control end of the reactor-entering gas control equipment is connected with the output end of the controller; a cooling liquid inlet of the electric pile is connected with a cooling liquid outlet thereof through the cooling liquid temperature adjusting equipment; and the control end of the cooling liquid temperature adjusting device is connected with the output end of the controller. The output end of the controllable switch I is connected with the control end of the DC-DC converter; the output end of the controllable switch II is connected with the control end of the voltage inspection device.
And the reactor gas control equipment is used for controlling the flow and pressure of reactor hydrogen and air.
And the cooling liquid temperature adjusting device is used for controlling the temperature of the cooling liquid entering the pile.
And the controllable switch I is used for controlling the starting of the DC-DC converter.
And the controllable switch II is used for controlling the starting of the voltage inspection device.
Preferably, the data processing and control unit executes the following program:
SS1, acquiring real-time electric pile output current, and judging whether the fuel cell normally operates; if the fuel cell is abnormally operated, adjusting the operation parameters of the fuel cell until the fuel cell is normally operated; the operation parameters comprise at least one of flow rate, pressure and water temperature of reactor entering cooling liquid of reactor entering hydrogen and air;
SS2, starting the DC-DC converter, and sending an alternating current excitation signal with preset frequency to the galvanic pile;
SS3, monitoring the value measured by the current sensor, and starting the voltage inspection device after the value measured by the current sensor is stable;
SS4, obtaining the current measured by the current sensor at the same time after the voltage inspection device is started and the voltage of each single battery measured by the voltage inspection device;
SS5, obtaining the amplitude and the phase of the alternating current impedance of each single battery under the preset frequency according to the voltage and the current;
SS6, adjusting the operation parameters of the fuel cell according to the obtained amplitude and phase of the alternating current impedance of each single cell, and controlling the operation of the electric pile.
Preferably, the controller performs the following procedure to complete step SS 1:
SS11, acquiring the real-time output current of the galvanic pile in a preset time period;
SS12, determining the effective value and the maximum variation of the real-time output current;
SS13, judging whether the effective value of the real-time output current is in a preset range and simultaneously meeting the condition that the maximum variation does not exceed a preset threshold; if yes, judging that the fuel cell normally operates; otherwise, adjusting the operation parameters of the fuel cell, including the flow and pressure of the hydrogen and air in the stack and the water temperature of the cooling liquid in the stack, and judging again until the fuel cell is judged to normally operate.
Preferably, the controller obtains the second value by the following formulaiAmplitude of AC impedance of single-chip batteryZ fi And phase (Z fi ) Is composed of
Z fi =ΔV i /ΔI
phase(Z fi )=β 2 -β i1
In the formula,. DELTA.VIs as followsiMagnitude of voltage vector, Delta, of individual monolithic cellsIIs the magnitude of the current vector and,β 2 is the phase angle of the current vector,β i1is as followsiVoltage of single chip batteryThe phase angle of the quantity is determined,i=1,…,n，nis the number of single cells in the stack.
Preferably, the controller performs the following procedure to complete step SS 6:
SS61 obtaining the amplitude of the AC impedance of each monolithic cellZ fi And phase (Z fi ) And the magnitude of the voltage vector of each monolithic cellV；
SS62. every amplitude AVRespectively, are compared with a preset value one if the amplitude value deltaVIf the number of the single-chip batteries smaller than or equal to the preset value I exceeds a rated value, judging that the input gas of the galvanic pile is insufficient, and controlling the flow and pressure of the hydrogen and air entering the galvanic pile to increase, otherwise, maintaining the flow and pressure of the hydrogen and air entering the galvanic pile unchanged;
SS63. comparing each said amplitudeZ fi Comparing with the second preset value, if the amplitude value is larger than the second preset valueZ fi If the number of the single-chip batteries greater than or equal to the second preset value exceeds a rated value, the proton exchange membrane of the galvanic pile is judged to be in a dry state, the cooling liquid temperature regulating equipment is controlled to reduce the water temperature of the cooling liquid entering the galvanic pile, and if not, the current water temperature is maintained unchanged;
SS64 according to the phase (Z fi ) Determining the time from the next starting time of the voltage inspection device to the signal acquisition timet
t=∑phase(Z fi )/（2nπf）+t 0
In the formula (I), the compound is shown in the specification,t 0the time from the moment of starting the voltage inspection device to the moment of signal acquisition,fthe frequency of the ac excitation signal.
Preferably, the impedance measurement and control device further comprises a variable resistor. The variable resistor is connected with the power supply end of the fuel cell stack, and the control end of the variable resistor is connected with the output end of the controller.
Preferably, the impedance measurement and control device further comprises a heating resistor and a battery. The heating resistor is arranged between any two adjacent battery units of the fuel cell stack, and the power supply end of the heating resistor is connected with the output end of the battery.
Preferably, the data processing unit has a display module. And the display screen of the display module displays the whole internal resistance of the fuel cell stack (for example, the sum of the internal resistances of all single cells can be adopted), and the internal resistance of each single cell in the stack.
Overall internal resistance of fuel cell stackZ f Obtained by the following formula
Z f= ∑Z fi
In the formula (I), the compound is shown in the specification,t 0the time from the moment of starting the voltage inspection device to the moment of signal acquisition,fis the frequency of the ac excitation signal,i=1,…,n，nis the number of single cells in the stack.
Preferably, the DC-DC converter further comprises an input capacitor, an output capacitor and a multi-phase parallel branch.
The multiphase parallel branch comprises a plurality of boost branches which are mutually connected in parallel, and each boost branch comprises a power inductor, a switching tube and a diode. In each boost branch circuit, a collector of the switching tube is respectively connected with one end of the power inductor and an anode of the diode, an emitter of the switching tube is respectively connected with a cathode of the fuel cell stack and one end of the variable resistor, and a base of the switching tube is connected with an output end of the controller; the other end of the power inductor is connected with the anode of the fuel cell stack; the cathode of the diode is connected to the other end of the variable resistor.
Preferably, the reactor gas control apparatus further comprises a control valve and an air compressor. The input end of the control valve is connected with the hydrogen inlet pipe, the output end of the control valve is connected with the hydrogen inlet of the fuel cell stack, and the control end of the control valve is connected with the control end of the controller. And the output end of the air compressor is connected with the air inlet of the electric pile, and the control end of the air compressor is connected with the control end of the controller.
Preferably, the coolant control apparatus further includes a thermostat, a radiator, and a water pump. The output end of the cooling liquid of the fuel cell stack is respectively connected with the input end of the radiator and the second port of the thermostat through a water pump; the output end of the radiator is connected with a first port of the thermostat; and a third port of the thermostat is connected with a cooling liquid input end of the electric pile.
Compared with embodiment 1, this embodiment adds a variable resistor, a heating resistor, and a battery, as well as a stack gas control apparatus, a coolant temperature adjustment apparatus, and further defines the mechanism of the DC-DC converter, the controller. The device can measure the impedance of the fuel cell monomer, provides the most accurate data for regulating and controlling fault diagnosis of the cell, and the reliability of the galvanic pile depends on the monomer cell with the worst performance in the galvanic pile.
Example 3
The invention also provides an impedance measurement and control method of the vehicle-mounted fuel cell corresponding to the devices of the embodiments 1 and 2, which comprises the following steps:
s1, when the galvanic pile normally operates, starting the DC-DC converter, and sending an alternating current excitation signal with preset frequency to the galvanic pile;
s2, starting the voltage inspection device after the value measured by the current sensor is stable;
and S3, obtaining the alternating current impedance of each single cell according to the voltage of each single cell in the galvanic pile at the same time and the current measured by the current sensor, and controlling the operation of the galvanic pile.
Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles of the embodiments, the practical application, or improvements made to the prior art, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (10)

1. An impedance measurement and control device of a vehicle-mounted fuel cell is characterized by comprising an electric pile, a DC-DC converter, a current sensor, a voltage inspection device and a controller; wherein the content of the first and second substances,
the DC-DC converter and the voltage inspection device are connected through a signal synchronization line; the current sensor is arranged inside the DC-DC converter; each electrode of the voltage inspection device is respectively connected with the output end of a single battery of the electric pile; the output ends of the current sensor and the voltage inspection device are respectively connected with the input end of the controller, and the control ends are respectively connected with the output end of the controller;
the controller is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal with preset frequency to the galvanic pile, starting the voltage inspection device after the value measured by the current sensor is stable, and controlling the operation of the galvanic pile by obtaining the alternating current impedance of each single battery according to the voltage of each single battery in the galvanic pile at the same feedback moment and the current measured by the current sensor.
2. The impedance measurement and control device of the vehicle-mounted fuel cell according to claim 1, wherein the controller further comprises:
the data acquisition unit is used for acquiring real-time data information in output signals of the current sensor and the voltage inspection device and sending the real-time data information to the data processing and control unit; the data information comprises the amplitude or effective value of the output current of the electric pile, and the amplitude or effective value of the voltage of each single battery;
the data processing and control unit is used for starting the DC-DC converter when the galvanic pile normally operates, sending an alternating current excitation signal with preset frequency to the galvanic pile, starting the voltage inspection device after the value measured by the current sensor is stable, combining the current amplitude with the voltage amplitude of each single battery at the same moment according to feedback to obtain the alternating current impedance of each single battery, and controlling the operation of the galvanic pile;
and the execution mechanism is used for changing the running state of the electric pile according to the control of the data processing unit.
3. The impedance measurement and control device for the vehicle-mounted fuel cell according to claim 2, wherein the actuator further comprises:
the reactor gas control equipment is used for controlling the flow and pressure of reactor hydrogen and air; the output end of the controller is connected with the gas inlet of the galvanic pile, and the control end of the controller is connected with the output end of the controller;
a coolant temperature adjusting device for controlling a temperature of the cooling liquid fed into the stack; the control end of the controller is connected with the output end of the controller; and a coolant inlet of the cell stack is connected to a coolant outlet thereof through the coolant temperature adjusting apparatus.
4. The impedance measurement and control device of the vehicle-mounted fuel cell according to claim 2 or 3, wherein the actuator further comprises a first controllable switch and a second controllable switch; wherein the content of the first and second substances,
the controllable switch I is used for controlling the starting of the DC-DC converter, and the output end of the controllable switch I is connected with the control end of the DC-DC converter;
and the controllable switch II is used for controlling the starting of the voltage inspection device, and the output end of the controllable switch II is connected with the control end of the voltage inspection device.
5. The impedance measurement and control device of a vehicle-mounted fuel cell according to any one of claims 1 to 3, wherein the data processing and control unit executes the following program:
acquiring real-time electric pile output current and judging whether the fuel cell normally operates or not; if the fuel cell is abnormally operated, adjusting the operation parameters of the fuel cell until the fuel cell is normally operated; the operation parameters comprise at least one of flow rate, pressure and water temperature of reactor entering cooling liquid of reactor entering hydrogen and air;
starting the DC-DC converter and sending an alternating current excitation signal with preset frequency to the galvanic pile;
monitoring the value measured by the current sensor, and starting the voltage inspection device after the value measured by the current sensor is stable;
obtaining the current measured by the current sensor at the same moment after the voltage inspection device is started and the voltage of each single battery measured by the voltage inspection device;
obtaining the amplitude and the phase of the alternating current impedance of each single battery under the preset frequency according to the voltage and the current;
and adjusting the operation parameters of the fuel cell according to the obtained amplitude and phase of the alternating current impedance of each single cell, and controlling the operation of the electric pile.
6. The impedance measurement and control device of the vehicle-mounted fuel cell according to claim 5, wherein the controller executes the following program to determine whether the fuel cell is operating normally:
acquiring real-time output current of the galvanic pile in a preset time period;
determining the effective value and the maximum variation of the real-time output current;
judging whether the effective value of the real-time output current is within a preset range or not, and simultaneously, meeting the condition that the maximum variation does not exceed a preset threshold; if yes, judging that the fuel cell normally operates; otherwise, adjusting the operation parameters of the fuel cell, including the flow and pressure of the hydrogen and air in the stack and the water temperature of the cooling liquid in the stack, and judging again until the fuel cell is judged to normally operate.
7. The on-vehicle fuel cell impedance measurement and control device of claim 6, wherein the second step isiAmplitude of AC impedance of single-chip batteryZ fi And phase (Z fi ) Is composed of
Z fi =ΔV i /ΔI
phase(Z fi )=β 2 -β i1
In the formula,. DELTA.VIs as followsiMagnitude of voltage vector, Delta, of individual monolithic cellsIIs the magnitude of the current vector and,β 2 is the phase angle of the current vector,β i1is as followsiThe phase angle of the voltage vector of the individual monolithic cells,i=1,…,n，nis the number of single cells in the stack.
8. The on-vehicle fuel cell impedance measurement and control device according to any one of claims 1 to 3 and 6 to 7, wherein the controller executes the following program to control stack operation:
obtaining the amplitude of the AC impedance of each single batteryZ fi And phase (Z fi ) And the magnitude of the voltage vector of each monolithic cellV；
Each of the amplitudes ΔVRespectively, are compared with a preset value one if the amplitude value deltaVIf the number of the single-chip batteries smaller than or equal to the preset value I exceeds a rated value, judging that the input gas of the galvanic pile is insufficient, and controlling the flow and pressure of the hydrogen and air entering the galvanic pile to increase, otherwise, maintaining the flow and pressure of the hydrogen and air entering the galvanic pile unchanged;
each of the amplitude valuesZ fi Comparing with the second preset value, if the amplitude value is larger than the second preset valueZ fi If the number of the single-chip batteries greater than or equal to the second preset value exceeds a rated value, the proton exchange membrane of the galvanic pile is judged to be in a dry state, the cooling liquid temperature regulating equipment is controlled to reduce the water temperature of the cooling liquid entering the galvanic pile, and if not, the current water temperature is maintained unchanged;
according to said phase (Z fi ) Determining the time from the next starting time of the voltage inspection device to the signal acquisition timet
t=∑phase(Z fi )/（2nπf）+t 0
In the formula (I), the compound is shown in the specification,t 0the time from the moment of starting the voltage inspection device to the moment of signal acquisition,fthe frequency of the ac excitation signal.
9. The impedance measurement and control device of the vehicle-mounted fuel cell according to claim 8, wherein the data processing and control unit has a display module; and the number of the first and second electrodes,
the display screen of the display module displays the integral internal resistance of the fuel cell stackZ f And the internal resistance of each single cell in the stackZ fi ；
The overall internal resistance of the fuel cell stackZ f Obtained by the following formula
Z f= ∑Z fi
In the formula (I), the compound is shown in the specification,t 0the time from the moment of starting the voltage inspection device to the moment of signal acquisition,fis the frequency of the ac excitation signal,i=1,…,n，nis the number of single cells in the stack.
10. An impedance measurement and control method of a vehicle-mounted fuel cell corresponding to the device according to claims 1-9, characterized by comprising the following steps:
when the galvanic pile normally operates, starting the DC-DC converter, and sending an alternating current excitation signal with preset frequency to the galvanic pile;
starting the voltage inspection device after the value measured by the current sensor is stable;
and according to the voltage of each single battery in the galvanic pile at the same time and the current measured by the current sensor, the alternating current impedance of each single battery is obtained, and the galvanic pile is controlled to operate.
CN202111272264.9A 2021-10-29 2021-10-29 Impedance measurement and control device and method for vehicle-mounted fuel cell Pending CN113823817A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114976142A (en) * 2022-05-09 2022-08-30 中国华能集团清洁能源技术研究院有限公司 Fuel cell stack voltage monitoring device and monitoring method
CN115332582A (en) * 2022-10-17 2022-11-11 北京亿华通科技股份有限公司 Low-temperature starting control system for fuel cell
CN116008664A (en) * 2023-03-28 2023-04-25 石家庄杰泰特动力能源有限公司 Impedance detection device for fuel cell controller
WO2023227060A1 (en) * 2022-05-25 2023-11-30 上海氢晨新能源科技有限公司 Online diagnosis method and system for vehicle-mounted fuel cell

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114976142A (en) * 2022-05-09 2022-08-30 中国华能集团清洁能源技术研究院有限公司 Fuel cell stack voltage monitoring device and monitoring method
CN114976142B (en) * 2022-05-09 2023-09-19 中国华能集团清洁能源技术研究院有限公司 Fuel cell stack voltage monitoring device and monitoring method
WO2023227060A1 (en) * 2022-05-25 2023-11-30 上海氢晨新能源科技有限公司 Online diagnosis method and system for vehicle-mounted fuel cell
CN115332582A (en) * 2022-10-17 2022-11-11 北京亿华通科技股份有限公司 Low-temperature starting control system for fuel cell
CN116008664A (en) * 2023-03-28 2023-04-25 石家庄杰泰特动力能源有限公司 Impedance detection device for fuel cell controller
CN116008664B (en) * 2023-03-28 2023-08-29 石家庄杰泰特动力能源有限公司 Impedance detection device for fuel cell controller

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