CN111381172A - Microgrid-based battery testing and chemical composition capacitive coupling system and control method - Google Patents

Abstract

The invention discloses a micro-grid-based battery testing and chemical composition capacity coupling system, comprising a fuel cell test unit, an energy storage unit, a lithium ion battery chemical composition capacity unit, an inverter unit, and an energy management unit; the energy management unit The fuel cell test unit, the energy storage unit, the lithium ion battery forming capacity unit and the inverter unit are respectively connected for communication, and the DC interfaces of the fuel cell test unit, the energy storage unit and the lithium ion battery forming capacity unit are connected to the DC bus. On L1; one end of the inverter unit is connected to the external power grid, and the other end is connected to the DC bus L1; a control method of a battery-based capacitive coupling system based on a micro-grid is also disclosed. The invention avoids the energy waste of the conventional resistance type load consuming the electric energy generated by the fuel cell system through thermal energy, and also saves the extra electric energy consumption for cooling the resistance type load equipment.

Description

Microgrid-based battery testing and chemical composition capacitive coupling system and control method

technical field

The invention belongs to the technical field of fuel cell testing, and in particular relates to a microgrid-based battery testing and chemical composition capacitance coupling system and control method.

Background technique

Large-scale research, validation and testing of fuel cell stacks, fuel cell systems and fuel cell engines are essential steps before fuel cell applications. Since the fuel cell itself is a power generation device that continuously consumes hydrogen, the first solution in the traditional performance test process is to use a resistive load to consume the electrical energy generated by the fuel cell system through thermal energy, resulting in a waste of resources and an increase in cost. . In addition, the commonly used electronic loads also require cooling towers, large fans and even air conditioners to dissipate heat during the process of releasing heat energy to ensure the normal operation of the electronic loads, so additional power is required; For the fuel cell power system, whose power exceeds 30kW or even as high as 100kW, the test method using electronic load will generate a great waste of electric energy and the test cost will rise.

The second solution is to use a grid-feeding electronic load to feed back the electrical energy output during the fuel cell test to the grid. Although this solution can effectively avoid the heat consumption of the fuel cell during the test and discharge process, due to the complexity and diversity of the test process (such as frequent start-stop loading, acceleration, and test polarization curves, etc.) When feeding power to the power grid under certain circumstances, it will cause serious interference of high-frequency harmonics to the power grid, and it is difficult to deal with it, which seriously affects the power quality of the power grid, and even causes an impact on the power grid.

The third scheme is to obtain hydrogen by electrolyzing water to produce hydrogen from the electrical energy output during the fuel cell testing process and pass it into the fuel cell for recycling. However, the conversion efficiency of hydrogen into electricity during fuel cell operation is generally 50% (based on the low calorific value LHV of hydrogen), while the theoretical electrolysis efficiency of the electricity generated by electrolyzing water to hydrogen again is high (the apparent conversion efficiency is even up to 100% to 122%), but in order to increase the hydrogen production rate in industry, the power conversion efficiency is only 50% to 70% due to factors such as heating and the generated polarization overpotential. Then the complete cycle efficiency of hydrogen→fuel cell→electrolyzer→hydrogen is only 30%, the energy loss exceeds 70%, the energy utilization rate is extremely low, and the electrolysis of water to hydrogen production system (especially the precious metal platinum or iridium as a catalyst) The solid electrolyte membrane electrolysis water hydrogen production system) has higher cost and shorter lifespan. Therefore, this solution is not economical, and there are problems of complicated system and complicated maintenance.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a microgrid-based battery testing and chemical composition capacitance coupling system and control method.

In order to achieve the above object, the technical scheme of the present invention is achieved in this way:

An embodiment of the present invention provides a microgrid-based battery testing and chemical composition capacitance coupling system, which includes a fuel cell test unit, an energy storage unit, a lithium ion battery chemical composition capacity unit, an inverter unit, and an energy management unit; the energy The management unit is respectively connected in communication with the fuel cell test unit, the energy storage unit, the lithium ion battery forming capacity unit and the inverter unit, and the DC interface of the fuel cell test unit, the energy storage unit and the lithium ion battery forming capacity unit is connected to the on the DC bus L1; one end of the inverter unit is connected to the external power grid, and the other end is connected to the DC bus L1.

In the above solution, the fuel cell test unit includes several fuel cell test groups and a first circuit breaker, and the several fuel cell test groups are respectively connected to the DC bus L1 through the first circuit breaker; each fuel cell test group includes: A fuel cell test bench and a unidirectional DC/DC converter, wherein the DC output end of the fuel cell to be tested in the fuel cell test bench is electrically connected to the corresponding input end of the unidirectional DC/DC converter, and the unidirectional DC/DC converter is electrically connected. The output to the DC/DC converter is connected to the DC bus L1 through a first circuit breaker.

In the above solution, the energy storage unit includes an energy storage battery pack, a battery management system BMS, a first bidirectional DC/DC converter and a second circuit breaker, and the energy storage battery pack and the first bidirectional DC/DC converter One end of the first bidirectional DC/DC converter is electrically connected to one end, the other end of the first bidirectional DC/DC converter is connected to the DC bus L1 through the second circuit breaker, and the battery management system BMS is connected to the energy storage battery pack through a low-voltage signal line .

In the above solution, the energy storage battery pack adopts one or more of lead-acid batteries, lead-carbon batteries, lithium-ion batteries, flow batteries, and sodium-sulfur batteries.

In the above solution, the lithium-ion battery forming capacity unit includes several lithium ion battery forming capacity groups and a third circuit breaker, and the several lithium ion battery forming capacity groups pass through the third circuit breaker and the DC bus L1 respectively. connection; each lithium-ion battery cell-forming container includes a lithium-ion battery cell-forming container, a second bidirectional DC/DC converter, and the lithium-ion battery cell-forming container corresponds to the second One end of the bidirectional DC/DC converter is electrically connected, and the other end of the second bidirectional DC/DC converter is connected to the DC bus L1 through a third circuit breaker.

In the above solution, the inverter unit includes a bidirectional AC/DC inverter and a grid-connected isolation switch, the DC terminal of the bidirectional AC/DC inverter is electrically connected to the DC bus L1, and the bidirectional AC/DC inverter The AC end of the device is connected to the power grid through the grid-connected isolation switch, and is used to realize bidirectional energy transfer between the DC bus L1 and the external power grid through the conversion of AC and DC under certain circumstances.

In the above solution, the energy management unit communicates with the fuel cell test bench and the one-way DC/DC converter in the fuel cell test unit, the battery management system BMS in the energy storage unit and the first two-way through the CAN line respectively. The DC/DC converter, the lithium-ion battery cells in the lithium-ion battery are converted into a container, the second bidirectional DC/DC converter, and the bidirectional AC/DC inverter in the inverter unit connected to the voltage of the first circuit breaker in the fuel cell test unit, the second circuit breaker in the energy storage unit, the third circuit breaker in the lithium-ion battery conversion unit, and the DC bus L1 through the low-voltage signal line respectively The current Hall sensor and the grid-connected isolation switch of the inverter unit are connected.

The embodiment of the present invention also provides a control method for a microgrid-based battery into a capacitive coupling system, and the method is implemented by the following steps:

In step (1), the energy management unit starts a self-check and confirms that the grid-connected isolation switch of the inverter unit is in a disconnected state, so that the fuel cell test and the lithium-ion battery into a capacitive coupling system enter the initial off-grid control mode ;

In step (2), the energy management unit determines the total amount of electricity Q ₁ generated by the fuel cell in the entire testing process through the fuel cell testing unit, and the energy storage unit determines that the energy storage battery pack is discharged from the current SOC to the set value. The dischargeable capacity Q ₂ when the SOC is at the lower limit and the chargeable capacity Q′ ₂ when the current SOC is charged to the set SOC upper limit are determined by the lithium-ion battery formation and capacity unit to determine the formation and/or capacity division of the lithium-ion battery cells. The total capacity Q ₃ to be charged; according to the magnitude relationship of Q ₁ , Q ₂ , Q′ ₂ and Q ₃ , it is determined to enter the steady-state off-grid working mode, namely step (3), or the transient grid-connected working mode, namely step (4);

In step (3), the energy management unit starts the fuel cell test unit to test the electrochemical performance of the fuel cell to be tested, and starts the lithium-ion battery compositing unit to charge and discharge the lithium-ion battery cells that have entered the chemical compositing process, The grid-connected isolating switch of the inverter unit is always in an off state, wherein the energy management unit obtains the power Q _F generated by the fuel cell during the test process and the power required for charging the lithium-ion battery cell into a capacitor in real time. Q _C and the amount of electricity Q _D generated by discharge;

In step (4), the energy management unit starts the fuel cell test unit to perform an electrochemical performance test on the fuel cell to be tested, and starts the lithium ion battery compositing unit to charge and discharge the lithium ion battery cells that have entered the chemical compositing process, The energy management unit acquires, in real time, the amount of electricity Q _F generated by the fuel cell during the test, the state of charge SOC of the energy storage battery pack in the energy storage unit, and the amount of electricity Q _C required for charging the lithium-ion battery cells into components and the amount of electricity Q _D produced by the discharge.

In the above scheme, in the step (3), when it is detected that Q _F < Q _C or Q _F =0, that is, the fuel cell has not undergone an electrochemical test, the energy management unit provides the first bidirectional DC/ The DC converter and the second circuit breaker send a switch-on command and merge them into the DC bus L1 to convert the electric energy stored in the energy storage battery pack into a voltage matching the DC bus L1 via the first bidirectional DC/DC converter and then send it to the DC bus L1; when it is detected that Q _F ≥ Q _C or Q _D ≥ 0, that is, the lithium ion battery cells are in the discharge step or at rest, the energy management unit provides the first bidirectional DC/DC converter and the first bidirectional DC/DC converter in the energy storage unit. The second circuit breaker sends a switch-on command and merges it into the DC bus L1 to convert the surplus electric energy of the DC bus L1 into a voltage matching the charging voltage of the energy storage battery pack through the first bidirectional DC/DC converter and output it to the energy storage battery pack.

In the above solution, in the step (4), when it is detected that Q _F < _{QC or Q F =} 0, that is, the fuel cell has not undergone an electrochemical test, the energy management unit is ensuring grid-connected isolation in the inverter unit. In the case that the switch continues to be turned off, the electric energy stored in the energy storage battery pack in the energy storage unit is converted into a voltage matching the DC bus L1 through the first bidirectional DC/DC converter, and then sent to the DC bus L1 for charging. The lithium-ion battery cells in the process step supplement the electric energy, and when the energy management unit detects that the state of charge SOC of the energy storage battery pack in the energy storage unit has dropped to the set lower limit, the lithium-ion battery in the conversion process step When the cells still need to be charged, the grid-connected isolation switch of the inverter unit is closed, and the electric energy of the external grid is converted into a DC voltage that matches the DC bus L1 through the bidirectional AC/DC inverter, and then sent to the DC bus L1 to be the lithium battery that is being charged. Ion battery cells supply power; when it is detected that Q _F ≥ Q _C or Q _D ≥ 0, that is, the lithium ion battery cells are in the discharge step or at rest, the energy management unit is ensuring that the grid-connected isolation switch in the inverter unit In the case of continuing to keep disconnected, according to the voltage and current fluctuations of the DC bus L1 monitored in real time, the surplus electric energy in the DC bus L1 is converted into the energy storage battery pack through the first bidirectional DC/DC converter in the energy storage unit. After the charging voltage matches the voltage, it is output to the energy storage battery pack, and when the energy management unit detects that the state of charge SOC of the energy storage battery pack has risen to the set upper limit while the fuel cell test is still in progress and/or lithium ion When the battery cells are still discharging or standing still, the grid-connected isolation switch of the inverter unit is closed to convert the electric energy in the DC bus L1 into the specified AC voltage through the bidirectional AC/DC inverter of the inverter unit and then send it to the external grid. Ensure the orderly and smooth operation of fuel cell testing and lithium-ion battery formation.

Compared with the prior art, the present invention uses the electric energy generated in the electrochemical test process of the fuel cell for the chemical composition of the lithium-ion battery by constructing a DC microgrid, and on the one hand, avoids the conventional resistance load from converting the electric energy generated by the fuel cell system. The waste of energy consumed by thermal energy also saves additional power consumption for cooling the resistance load; Frequently taking electricity from the external power grid for charging and then discharging it in the form of resistive heat energy wastes electricity, and the more charging and discharging times, the greater the waste of electricity. Therefore, the microgrid-based battery-capacity coupling system provided by the present invention realizes the efficient utilization of electric energy in the fuel cell testing and the lithium-ion battery-capacity process, and thus greatly saves electricity costs.

Description of drawings

FIG. 1 is a schematic structural diagram of a microgrid-based battery testing and chemical composition capacitive coupling system according to an embodiment of the present invention.

FIG. 2 is a flowchart of a control method of a microgrid-based battery testing and chemical composition capacitive coupling system according to an embodiment of the present invention.

Detailed ways

The embodiments of the present invention will be further described below with reference to the accompanying drawings, and the advantages and features of the present invention will become more apparent with the description. However, the embodiments are only exemplary and do not limit the scope of the present invention in any way. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention can be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the protection scope of the present invention.

In addition, in order to better illustrate the present invention, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other embodiments, well-known methods, procedures, components and circuits are not described in detail so as to highlight the gist of the present invention.

An embodiment of the present invention provides a microgrid-based battery testing and chemical composition capacitance coupling system, as shown in FIG. 1, which includes a fuel cell test unit 1, an energy storage unit 2, a lithium ion battery chemical composition unit 3, an inverter Unit 4, energy management unit 5; the energy management unit 5 is respectively connected to the fuel cell test unit 1, the energy storage unit 2, the lithium-ion battery into a capacity unit 3, and the inverter unit 4. The fuel cell test unit 1 is in communication connection. The DC interface of the energy storage unit 2 and the lithium-ion battery into a capacity unit 3 is connected to the DC bus L1; one end of the inverter unit 4 is connected to the external power grid, and the other end is connected to the DC bus L1.

The fuel cell test unit 1 includes several fuel cell test groups and a first circuit breaker 13, and the several fuel cell test groups are respectively connected to the DC bus L1 through the first circuit breaker 13; each fuel cell test group Including a fuel cell test bench 11 and a unidirectional DC/DC converter 12, the DC output end of the fuel cell to be tested in the fuel cell test bench 11 corresponds to the input end of the unidirectional DC/DC converter 12 For electrical connection, the output end of the unidirectional DC/DC converter 12 is connected to the DC bus L1 through the first circuit breaker 13 .

The fuel cell test bench 11 in the fuel cell test unit 1 is used to test and evaluate the polarization curve, electrochemical impedance spectroscopy (EIS) and electrochemical performance of the fuel cell under various simulated working conditions, and the The one-way DC/DC converter 12 sends the electric energy generated by the fuel cell in the test process into the DC bus L1 after voltage conversion.

Further, the fuel cell test bench 11 described in the fuel cell test unit 1 may be a single set or multiple sets to form a fuel cell test bench array, and each of the fuel cell test benches in the fuel cell test bench array The battery test benches work independently and do not interfere with each other; and, the number of the one-way DC/DC converters 12 is consistent with the number of the fuel cell test benches 11 and forms a one-to-one correspondence.

Optionally, the fuel cell test bench 11 includes but is not limited to a hydrogen flow test unit, an air flow test unit, a water management unit, a thermal management unit and a control unit, and the tested fuel cells include but are not limited to single fuel cell, Fuel cell stacks, fuel cell systems, fuel cell engines, etc.; moreover, different fuel cells have different configurations of the corresponding fuel cell test benches, as long as the tested fuel cell type and test parameters are the same as the fuel cell test The table can be matched. Similarly, the configuration parameters of the unidirectional DC/DC converter 12 corresponding to the fuel cell test platform will also be different due to the voltage and current of the fuel cell to be tested, as long as the voltage and current range that can be converted is the same as the output of the fuel cell. The voltage and current can be matched. In other words, in the above fuel cell test bench array, the fuel cell test benches 11 may be of the same type or of different types; correspondingly, the unidirectional DC/DC converter 12 may also be of the same type, It can also be of different types, but the input configuration parameters of each unidirectional DC/DC converter 12 must match the electrical output parameters of the fuel cell test bench to which it is connected, and the output configuration parameters must also match the DC bus. The voltage and current parameters of L1 are matched.

The energy storage unit 2 includes an energy storage battery pack 21, a battery management system BMS22, a first bidirectional DC/DC converter 23 and a second circuit breaker 24. The energy storage battery pack 21 is connected to the first bidirectional DC/DC. One end of the converter 23 is electrically connected, the other end of the first bidirectional DC/DC converter 23 is connected to the DC bus L1 through the second circuit breaker 24, and the battery management system BMS22 is connected to the storage battery through a low-voltage signal line. The battery pack 21 can be connected.

The energy storage battery pack 21 of the energy storage unit 2 is used to realize the bidirectional transmission of DC power with the DC bus L1 through the first bidirectional DC/DC converter 23: The DC power generated by the fuel cell during the test process, the DC power released by the lithium-ion battery cells of the lithium-ion battery into the capacity unit 3 during the discharge step, and the AC power transmitted from the external power grid via the inverter unit 4 On the other hand, the lithium-ion battery is converted into a capacity unit 3 to directly provide DC power and feed power to the external grid through the inverter unit 4, and provide power auxiliary services for peak regulation, frequency regulation and reactive power compensation for the external grid.

Optionally, the energy storage battery pack 21 adopts one or more of lead-acid batteries, lead-carbon batteries, lithium-ion batteries, flow batteries, and sodium-sulfur batteries;

Preferably, the energy storage battery pack 21 preferably adopts a lithium titanate battery or an all-vanadium flow battery.

The battery management system BMS22 in the energy storage unit 2 is used to monitor the voltage, current and temperature of the energy storage battery pack 21, accurately estimate the state of charge SOC of the energy storage battery pack 21, and collect the data in real time. The data information is transmitted to the energy management unit 5 through the CAN line, and at the same time, energy balance is performed between the single cells of the energy storage battery pack 21 .

The lithium ion battery forming capacity unit 3 includes several lithium ion battery forming capacity groups and a third circuit breaker 33 , and the several lithium ion battery forming capacity groups are respectively connected to the DC bus L1 through the third circuit breaker 33 . ; Each lithium-ion battery cell composition container 31, a second bidirectional DC/DC converter 32, and the lithium-ion battery cell composition container 31 corresponding to the lithium-ion battery cell composition container 31 One end of the second bidirectional DC/DC converter 32 is electrically connected, and the other end of the second bidirectional DC/DC converter 32 is connected to the DC bus L1 through the third circuit breaker 33 .

The lithium-ion battery cell-forming container 31 in the lithium-ion battery cell-forming capacity unit 3 is used to enter the lithium-ion battery through the bidirectional energy transfer pair between the second bidirectional DC/DC converter 32 and the DC bus L1. The second bidirectional DC/DC converter 32 is used to convert the lithium-ion battery cells into the space between the storage cabinet 31 and the DC bus L1 by converting the DC voltage. and the number of the second bidirectional DC/DC converters 32 is consistent with the number of the lithium-ion battery cell-forming cabinets 31 and forms a one-to-one correspondence.

Further, the lithium-ion battery cell composition container 31 may be a single unit or multiple units to form a lithium-ion battery cell composition container array; and the lithium-ion battery cell composition container array Each of the lithium-ion battery cell components in the container works independently and does not interfere with each other.

Optionally, in the above-mentioned lithium-ion battery cell formation and composition container array, according to the difference in the type and capacity (amp-hours) of the lithium-ion battery cells entering the formation and composition process, the corresponding lithium ion The specific parameter configuration of the battery cells into the container 31 is also different, as long as the configuration matches the process parameters of the lithium-ion battery cells that need to be converted into capacity; similarly, with the lithium-ion battery cells The configuration parameters of the second bidirectional DC/DC converter 32 corresponding to the composition container 31 are also different due to the voltage and current of the lithium-ion battery cells that need to be converted into a capacity, as long as it can convert The voltage and current range of the battery can match the voltage and current of the lithium-ion battery cell charging and discharging. In other words, in the above-mentioned lithium-ion battery cell-forming cabinet array, the lithium-ion battery cell-forming cabinets 31 may be of the same type or different types; correspondingly, the second bidirectional DC/DC The converters 32 can also be of the same type or of different types, but the configuration parameters at both ends of each second bidirectional DC/DC converter 32 must be respectively combined with the lithium-ion battery cells connected to the container 31 . The input and output parameters match the voltage and current parameters of the DC bus L1.

The inverter unit 4 includes a bidirectional AC/DC inverter 41 and a grid-connected isolation switch 42. The DC terminal of the bidirectional AC/DC inverter 41 is electrically connected to the DC bus L1, and the bidirectional AC/DC inverter The AC end of the device 41 is connected to the power grid through the grid-connected isolation switch 42, for realizing bidirectional energy transfer between the DC bus L1 and the external power grid through AC-DC conversion under certain circumstances.

The energy management unit 5 communicates with the fuel cell test bench 11 and the one-way DC/DC converter 12 in the fuel cell test unit 1, the battery management system BMS22 in the energy storage unit 2, and the third battery through the CAN line, respectively. A bidirectional DC/DC converter 23 , the lithium ion battery cells in the lithium ion battery are converted into a container 31 , a second bidirectional DC/DC converter 32 and a battery in the inverter unit 4 The bidirectional AC/DC inverter 41 is connected to the first circuit breaker 13 in the fuel cell test unit 1, the second circuit breaker 24 in the energy storage unit 2, and the lithium ion battery through low-voltage signal lines, respectively, into a capacity unit The third circuit breaker 33 in 3, the voltage and current Hall sensor of the DC bus L1, and the grid-connected isolation switch 42 of the inverter unit 4 are connected to receive the fuel cell test unit 1, the energy storage unit 2, the lithium ion battery Convert the real-time parameter information of the capacity unit 3 and the DC bus L1, record, count, and analyze the power operation data of the entire microgrid system, and send the fuel cell test unit 1, energy storage unit 2, lithium battery to the fuel cell test unit 1, energy storage unit 2, lithium The control elements and circuit breakers of the ion battery are converted into capacity unit 3, inverter unit 4 and the circuit breaker issues operation instructions, and comprehensively manages and dispatches fuel cell testing, energy storage, lithium-ion battery cell conversion into capacity and grid energy exchange, enabling the entire microgrid The system operates in the best state and achieves better economic benefits.

The microgrid-based battery testing and chemical capacitive coupling system works in a steady-state off-grid working mode and a transient grid-connected working mode:

In the steady-state off-grid working mode, the energy management unit 5 sends a start signal to the fuel cell test bench 11 of the fuel cell test unit 1, and performs electrochemical performance test of the fuel cell to be tested according to preset parameters and working steps, and at the same time Send a switch-on command to the one-way DC/DC converter 12 and the first circuit breaker 13 corresponding to the fuel cell test bench 11 to convert the electric energy generated by the fuel cells tested online on the fuel cell test bench 11 through one-way DC/DC conversion The voltage of the device 12 is converted into a specified voltage and then sent to the DC bus L1; and according to the demand, the energy management unit 5 sends a start signal to the lithium-ion battery cell-forming container 31 in the lithium-ion battery cell-forming unit 3, according to The preset working step parameters and cycle parameters are used to charge and discharge the lithium-ion battery cells that have entered the chemical composition process, and at the same time, the lithium-ion battery cells are converted to the second bidirectional DC/DC converter 32 corresponding to the composition container 31. and the third circuit breaker 33 sends a turn-on command and is merged into the DC bus L1 to realize that the lithium-ion battery cells in the charging step will output the electrical energy in the DC bus L1 through the second bidirectional DC/DC converter 32 after voltage conversion to the lithium ion battery. The ion battery cells are converted into a container 31 for charging the lithium ion battery cells and the lithium ion battery cells convert the electric energy stored in the lithium ion battery cells into the specified voltage through the second bidirectional DC/DC converter 32 in the discharging step. The voltage is sent to the DC bus L1.

Wherein, the energy management unit 5 obtains in real time the power Q _F generated by the fuel cell during the test, the power Q _C required for charging the lithium-ion battery cells into a capacitor, and the power Q _D generated by the discharge: when the detection of Q _F < Q _C or Q _F = 0, that is, when the fuel cell is not electrochemically tested, the energy management unit 5 sends a turn-on command to the first bidirectional DC/DC converter 23 and the second circuit breaker 24 in the energy storage unit 2 to incorporate The DC bus L1 converts the electrical energy stored in the energy storage battery pack 21 into a specified voltage through the first bidirectional DC/DC converter 23 and then sends it to the DC bus L1, so as to charge and supplement the lithium-ion battery cells that are being converted into capacity. Provide electric energy; when it is detected that Q _F ≥ Q _C or Q _D ≥ 0, that is, the lithium ion battery cell is in the discharge step or at rest, the energy management unit 5 provides the first bidirectional DC/DC converter 23 in the energy storage unit 2 And the second circuit breaker 24 sends a closing command to merge into the DC bus L1 to convert the surplus electric energy of the DC bus L1 into a specified voltage through the first bidirectional DC/DC converter 23 and then output it to the energy storage battery pack 21, thereby maintaining fuel. The battery test and lithium-ion battery cell formation are carried out normally and the voltage fluctuation of the DC bus L1 is suppressed.

During the entire process of fuel cell testing and lithium-ion battery cell formation, the electrical energy generated by the fuel cell is only transferred between fuel cell test unit 1, energy storage unit 2, and lithium-ion battery formation and capacity unit 3. The grid-connected isolation switch 42 of the inverter unit 4 is always in an off state, and the entire microgrid-based coupling system operates in an island.

In the transient grid-connected working mode, the energy management unit 5 sends a start-up signal to the fuel cell test bench 11 in the fuel cell test unit 1, and performs electrochemical performance test of the fuel cell to be tested according to the preset parameters and working steps, and at the same time Send a switch-on command to the one-way DC/DC converter 12 and the first circuit breaker 13 corresponding to the fuel cell test bench 11 to convert the electric energy generated by the fuel cells tested online on the fuel cell test bench 11 through one-way DC/DC conversion The voltage of the device 12 is converted into a specified voltage and then sent to the DC bus L1; and according to the demand, the energy management unit 5 sends a start signal to the lithium-ion battery cell-forming container 31 in the lithium-ion battery cell-forming unit 3, according to The preset working step parameters and cycle parameters are used to charge and discharge the lithium-ion battery cells that have entered the chemical composition process, and at the same time, the lithium-ion battery cells are converted to the second bidirectional DC/DC converter 32 corresponding to the composition container 31. and the third circuit breaker 33 sends a turn-on command and is merged into the DC bus L1 to realize that the lithium-ion battery cells in the charging step will output the electrical energy in the DC bus L1 through the second bidirectional DC/DC converter 32 after voltage conversion to the lithium ion battery. The ion battery cells are converted into the container cabinet 31 for charging the lithium ion battery cells and the lithium ion battery cells in the discharging step convert the electric energy stored in the lithium ion battery cells through the second bidirectional DC/DC converter 32 into a predetermined voltage. The voltage is sent to the DC bus L1.

Wherein, the energy management unit 5 obtains in real time the quantity of electricity Q _F generated by the fuel cell during the test process, the state of charge SOC of the energy storage battery pack 21 in the energy storage unit 2 , and the energy required for charging the lithium-ion battery cells into components. The amount of electricity Q _C and the amount of electricity Q _D generated by discharge: when it is detected that Q _F < Q _C or Q _F =0, that is, the fuel cell has not been electrochemically tested, the energy management unit 5 preferentially stores the energy in the energy storage unit 2 The electric energy stored in the battery pack 21 is converted into a specified voltage by the first bidirectional DC/DC converter 23 and then sent to the DC bus L1 to supplement electric energy for the lithium-ion battery cells in the charging step. When the energy management unit 5 When it is detected that the state of charge SOC of the energy storage battery pack 21 has dropped to the set lower limit and the lithium-ion battery cells in the process of converting into capacity still need to be charged, the grid-connected isolation switch 42 of the inverter unit 4 is closed to connect the external grid. The electric energy is converted into a specified DC voltage by the bidirectional AC/DC inverter 41 of the inverter unit 4 and then sent to the DC bus L1 to supply power for the lithium-ion battery cells being charged; when it is detected that Q _F ≥ Q _C or Q _D ≥ 0, that is, when the lithium-ion battery cell is in the discharge step or at rest, the surplus electric energy in the DC bus L1 is converted into a specified voltage through the first bidirectional DC/DC converter 23 and then output to the energy storage battery pack 21. When The energy management unit 5 detects that the state of charge SOC of the energy storage battery pack 21 has risen to the set upper limit while the fuel cell test is still in progress. The electric energy is converted into a predetermined AC voltage through the bidirectional AC/DC inverter 41 of the inverter unit 4 and then sent to the external power grid. So as to ensure the orderly and stable operation of the fuel cell test and the lithium-ion battery composition and the stability of the DC bus L1 voltage.

The invention uses the electric energy generated in the electrochemical test process of the fuel cell for the chemical composition of the lithium-ion battery by constructing a DC microgrid, and on the one hand, avoids the energy waste of the conventional resistive load consuming the electric energy generated by the fuel cell system through thermal energy. At the same time, it also saves the extra power consumption for cooling the resistive load; on the other hand, the use of energy storage battery packs in the DC microgrid avoids the frequent use of electricity from the external grid during the process of converting lithium-ion batteries into capacitance. The electric energy that is charged and then discharged in the form of resistance heat energy is wasted, and the more charging and discharging times, the greater the electric energy waste. Therefore, the microgrid-based battery testing and chemical composition capacitance coupling system provided by the present invention realizes the efficient utilization of electric energy in the fuel cell test and the chemical composition and capacitance process of the lithium ion battery, and thus greatly saves the electricity cost.

In addition, when it is necessary to transmit power to the power grid in extreme cases, the coupling system provided by the present invention can avoid the serious interference of the high-frequency harmonics of the power grid caused by the usual grid-feeding electronic load due to the use of energy storage battery packs, and ensure the power grid. Power quality; on the other hand, it can realize peak shaving and valley filling, harmonic control and reactive power compensation of the power grid, and improve the power quality of the power grid; at the same time, the use of energy storage battery packs can also be used for valley power peaks, peak regulation and frequency regulation. Ancillary services bring additional benefits to the business.

The embodiment of the present invention also provides a microgrid-based battery testing and chemical composition capacitive coupling system control method, as shown in FIG. 2 , the method is implemented by the following steps:

In step 200, the energy management unit 5 starts a self-check, and confirms that the grid-connected isolation switch 42 of the inverter unit 4 is in a disconnected state, so that the microgrid-based battery testing and chemical-capacitive coupling system enters the initial isolation network control mode. Then go to step 201 .

In step 201, the energy management unit 5 obtains the number and test parameters of the fuel cells to be tested in the fuel cell test unit 1 to calculate the total amount of electricity Q ₁ generated by the fuel cell in the entire test process. The BMS 22 in the energy storage unit 2 obtains the SOC of the energy storage battery pack 21 to calculate the dischargeable amount Q ₂ when the energy storage battery pack 21 is discharged from the current SOC to the set SOC lower limit, and the current SOC is charged to the set SOC. When the upper limit is reached, the required charging amount Q′ ₂ is obtained, and the capacity model (namely the number of ampere hours) and the number of lithium-ion battery cells in the lithium-ion battery cell-forming capacity unit 3 in the lithium-ion battery cell-forming capacity cabinet 31 are obtained to calculate _Obtain the total capacity Q ₃ that needs to be charged during the formation and/or capacity separation _of the lithium _- ion battery cells _;

In step 202, when the energy management unit 5 detects that Q _{1 ≤Q} ' ₂ and Q ₃ ≤Q ₁ +Q ₂ >Q′ ₂ or Q ₃ >Q ₁ +Q ₂ , then enter step 220 , that is, enter the transient grid-connected working mode.

In step 210, the energy management unit 5 sends a start-up signal to the fuel cell test bench 11 in the fuel cell test unit 1, performs electrochemical performance test of the fuel cell to be tested according to preset parameters and steps, and simultaneously tests the fuel cell The one-way DC/DC converter 12 corresponding to the platform 11 and the first circuit breaker 13 send a switch-on command to convert the electric energy generated by the fuel cell tested online on the fuel cell test platform 11 through the one-way DC/DC converter 12. The voltage that matches the DC bus L1 is sent to the DC bus L1; and the energy management unit 5 sends a start signal to the lithium-ion battery cell-forming container 31 in the lithium-ion battery cell-forming capacity unit 3 according to requirements, Charge and discharge the lithium-ion battery cells that have entered the chemical composition process according to the preset process parameters and cycle parameters, and at the same time convert the lithium-ion battery cells into the second bidirectional DC/DC converter corresponding to the composition container 31 32 and the third circuit breaker 33 send a switch-on command and merge into the DC bus L1 to realize that the lithium-ion battery cells in the charging step will output the electric energy in the DC bus L1 through the second bidirectional DC/DC converter 32 after voltage conversion to the DC bus L1. The lithium ion battery cells are converted into a container 31 for charging the lithium ion battery cells and the lithium ion battery cells convert the electric energy stored in the lithium ion battery cells through the second bidirectional DC/DC converter 32 into a voltage in the discharging step. The voltage matched with the DC bus L1 is sent to the DC bus L1. During the whole process of fuel cell testing and lithium-ion battery cell formation, the electrical energy generated by the fuel cell is only transferred between fuel cell test unit 1, energy storage unit 2, and lithium-ion battery formation and capacity unit 3. The grid-connected isolating switch 42 of the inverter unit 4 is always in an off state, and the entire microgrid-based coupling system operates in an island.

Wherein, the energy management unit obtains the power Q _F generated by the fuel cell during the test process, the power Q _C required for the lithium-ion battery cell-forming capacity charging, and the power Q _D generated by discharge in real time, and then compares Q _F with The size between Q and _C and the situation of Q _D and go to step 211 .

In step 211, the energy management unit 5 starts to detect whether there is a situation where Q _F < _{QC or Q F =} 0, that is, the fuel cell has not been electrochemically tested: if so, go to step 212, if not, go to step 213 .

In step 212 , the energy management unit 5 sends a turn-on instruction to the first bidirectional DC/DC converter 23 and the second circuit breaker 24 in the energy storage unit 2 and merge them into the DC bus L1 to store the energy stored in the energy storage battery 21 . The electric energy is converted into a voltage matching the DC bus L1 through the first bidirectional DC/DC converter 23 and then sent to the DC bus L1, so as to supplement or provide electric energy for charging the lithium-ion battery cells that are being converted into capacity; The energy management unit 5 sends a disconnection signal to the third circuit breaker 33 corresponding to the one or more lithium-ion battery cell-forming cabinets 31 according to the voltage and current fluctuations of the DC bus L1 monitored in real time to collect the lithium-ion battery power. The strategy of timely charging delay of the core is used to ensure the stability of the DC bus L1 voltage.

In step 213, the energy management unit 5 starts to detect whether there is a situation where Q _F ≥ _{QC or Q D ≥} 0, that is, the lithium-ion battery cells are in the discharge step or at rest: if so, go to step 214, if not If there is, return to step 211 .

In step 214, the energy management unit 5 sends a turn-on command to the first bidirectional DC/DC converter 23 and the second circuit breaker 24 in the energy storage unit 2 to merge into the DC bus L1 so that the surplus electric energy of the DC bus L1 passes through the A bidirectional DC/DC converter 23 is converted into a voltage matching the charging voltage of the energy storage battery pack 21 and then output to the energy storage battery pack 21, so as to maintain the normal progress of fuel cell testing and lithium-ion battery cell formation; Meanwhile, when the fuel cell test and the lithium-ion battery cell discharge step are carried out simultaneously, the energy management unit 5 sends one or more fuel cell test benches to one or more fuel cell test benches according to the voltage and current fluctuations of the DC bus L1 monitored in real time. 11 Send a pause signal to adopt a strategy of timely delaying the fuel cell test to ensure the stability of the DC bus L1 voltage.

In step 220, the energy management unit 5 sends a start-up signal to the fuel cell test bench 11 in the fuel cell test unit 1, performs electrochemical performance test of the fuel cell to be tested according to preset parameters and steps, and simultaneously tests the fuel cell The one-way DC/DC converter 12 corresponding to the platform 11 and the first circuit breaker 13 send a switch-on command to convert the electric energy generated by the fuel cell tested online on the fuel cell test platform 11 through the one-way DC/DC converter 12. The voltage that matches the DC bus L1 is sent to the DC bus L1; and the energy management unit 5 sends a start signal to the lithium-ion battery cell-forming container 31 in the lithium-ion battery cell-forming capacity unit 3 according to requirements, Charge and discharge the lithium-ion battery cells that have entered the chemical composition process according to the preset process parameters and cycle parameters, and at the same time convert the lithium-ion battery cells into the second bidirectional DC/DC converter corresponding to the composition container 31 32 and the third circuit breaker 33 send a turn-on command and merge into the DC bus L1 to realize that the lithium-ion battery cells in the charging step will output the electric energy in the DC bus L1 through the second bidirectional DC/DC converter 32 after voltage conversion to the DC bus L1. The lithium-ion battery cells are converted into a container 31 for charging the lithium-ion battery cells, and the lithium-ion battery cells convert the electric energy stored in the lithium-ion battery cells through the second bidirectional DC/DC converter 32 into a voltage in the discharging step. The voltage matched with the DC bus L1 is sent to the DC bus L1.

The energy management unit acquires, in real time, the amount of electricity Q _F generated by the fuel cell during the test, the state of charge SOC of the energy storage battery pack in the energy storage unit, and the amount of electricity Q _C required for charging the lithium-ion battery cells into components and the amount of electricity Q _D generated by the discharge, then compare the magnitude between Q _F and Q _C and the condition of Q _D and enter step 221 .

In step 221, the energy management unit 5 starts to detect whether there is a situation where Q _F <Q _C or Q _F =0, that is, the fuel cell has not been electrochemically tested: if so, go to step 222, if not, go to step 225 .

In step 222 , the energy management unit 5 continues to detect whether the state of charge SOC of the energy storage battery pack 21 drops to the set lower limit: if not, go to step 223 , and if so, go to step 224 .

In step 223, the energy management unit 5 preferentially transfers the electrical energy stored in the energy storage battery pack 21 in the energy storage unit 2 via the first The bidirectional DC/DC converter 23 is converted into a voltage matching the DC bus L1 and then sent to the DC bus L1 to supplement the electric energy for the lithium-ion battery cells in the charging step; The voltage and current fluctuations of the DC bus L1 send a disconnection signal to the third circuit breaker 33 corresponding to one or more lithium-ion battery cell-forming cabinets 31 in the lithium-ion battery conversion unit 3 to take the lithium-ion battery The strategy of timely charging delay of cells ensures the stability of DC bus L1 voltage.

In step 224, the energy management unit 5 detects that the state of charge SOC of the energy storage battery pack 21 in the energy storage unit 2 has dropped to a set lower limit, and the lithium-ion battery cells in the process of converting into capacity are still When charging is required, the energy management unit 5 sends a closing signal to the grid-connected isolation switch 42 of the inverter unit 4 to convert the electric energy of the external grid into a DC voltage matching the DC bus L1 via the bidirectional AC/DC inverter 41 and then send it to the grid. The incoming DC bus L1 supplies power to the lithium-ion battery cells being charged.

In step 225, the energy management unit 5 starts to detect whether there is a situation where Q _F ≥ _{QC or Q D ≥} 0, that is, the lithium ion battery cells are in the discharge step or at rest: if so, go to step 226, if not If there is, return to step 221 .

In step 226 , the energy management unit 5 continues to detect whether the state of charge SOC of the energy storage battery pack 21 rises to the set upper limit: if not, go to step 227 , and if so, go to step 228 .

In step 227, the energy management unit 5, while ensuring that the grid-connected isolation switch 42 in the inverter unit 4 continues to be disconnected, switches the DC bus L1 to the DC bus L1 according to the voltage and current fluctuations of the DC bus L1 monitored in real time. The surplus electric energy is converted into a voltage matching the charging voltage of the energy storage battery pack 21 through the first bidirectional DC/DC converter 23 in the energy storage unit 2 and then output to the energy storage battery pack 21; When the discharge step of the lithium ion battery cell is performed simultaneously, the energy management unit 5 sends the information to one or more fuel cell test benches in the fuel cell test unit 1 according to the voltage and current fluctuations of the DC bus L1 monitored in real time. 11 Send a pause signal to adopt a strategy of timely delaying the fuel cell test to ensure the stability of the DC bus L1 voltage.

In step 228, the energy management unit 5 detects that the state of charge SOC of the energy storage battery pack 21 has risen to the set upper limit while the fuel cell test is still in progress and/or the lithium-ion battery cells are still discharged or static When set, the energy management unit 5 sends a closing signal to the grid-connected isolation switch 42 of the inverter unit 4 to convert the electric energy in the DC bus L1 into a specified AC voltage via the bidirectional AC/DC inverter 41 of the inverter unit 4 It is fed into the external power grid to ensure the orderly and smooth operation of fuel cell testing and lithium-ion battery formation.

The contents of the embodiments of the present invention are disclosed as above. However, the present embodiments are not intended to limit the scope of the present invention. Simple equivalent changes and modifications made according to the claims and descriptions of the present invention still belong to the technical solutions of the present invention. within the range.

Claims (10)

1. a microgrid-based battery testing and chemical composition capacitance coupling system, is characterized in that, it comprises fuel cell test unit, energy storage unit, lithium ion battery chemical composition capacity unit, inverter unit, energy management unit; Described The energy management unit is respectively connected with the fuel cell test unit, the energy storage unit, the lithium ion battery into a capacity unit and the inverter unit, and the fuel cell test unit, the energy storage unit and the lithium ion battery into the capacity unit are connected with the DC interface On the DC bus L1; one end of the inverter unit is connected to the external power grid, and the other end is connected to the DC bus L1. 2 . The microgrid-based battery testing and chemical composition capacitance coupling system according to claim 1 , wherein the fuel cell testing unit comprises several fuel cell testing groups and a first circuit breaker, and the several fuel cell testing The battery test groups are respectively connected to the DC bus L1 through the first circuit breaker; each fuel cell test group includes a fuel cell test stand 11 and a one-way DC/DC converter 12, and the fuel cell to be tested in the fuel cell test stand 11 The DC output end of the unidirectional DC/DC converter is electrically connected to the corresponding input end of the unidirectional DC/DC converter, and the output end of the unidirectional DC/DC converter is connected to the DC bus L1 through the first circuit breaker. 3. The microgrid-based battery testing and chemical composition-capacitive coupling system according to claim 1 or 2, wherein the energy storage unit comprises an energy storage battery pack, a battery management system BMS, a first bidirectional DC/DC a converter and a second circuit breaker, the energy storage battery pack is electrically connected to one end of the first bidirectional DC/DC converter, and the other end of the first bidirectional DC/DC converter passes through the second circuit breaker Connected to the DC bus L1, the battery management system BMS is connected to the energy storage battery pack through a low-voltage signal line. 4. The microgrid-based battery testing and chemical composition capacitance coupling system according to claim 3, wherein the energy storage battery pack adopts lead-acid battery, lead-carbon battery, lithium ion battery, flow battery, sodium One or more of sulfur batteries. 5 . The microgrid-based battery testing and chemical composition coupling system according to claim 4 , wherein the lithium ion battery chemical composition unit comprises several lithium ion battery chemical composition groups and a third circuit breaker. 6 . , the several lithium-ion battery-forming capacity groups are respectively connected to the DC bus L1 through the third circuit breaker; a converter, wherein the lithium-ion battery cells are formed into a container and electrically connected to one end of the corresponding second bidirectional DC/DC converter, and the other end of the second bidirectional DC/DC converter is disconnected through a third circuit The device is connected to the DC bus L1. 6 . The microgrid-based battery testing and chemical composition-capacitive coupling system according to claim 5 , wherein the inverter unit comprises a bidirectional AC/DC inverter and a grid-connected isolation switch, and the bidirectional AC/DC The DC terminal of the DC inverter is electrically connected to the DC bus L1, and the AC terminal of the bidirectional AC/DC inverter is connected to the grid through the grid-connected isolation switch, so as to realize DC through AC-DC conversion under certain circumstances Bidirectional energy transfer between bus L1 and external power grid. 7 . The microgrid-based battery testing and chemical composition capacitance coupling system according to claim 6 , wherein the energy management unit is connected to the fuel cell test bench and the single unit in the fuel cell testing unit through CAN lines, respectively. 8 . To the DC/DC converter, the battery management system BMS in the energy storage unit, the first bidirectional DC/DC converter, the lithium ion battery cells in the lithium ion battery into a container and the first Two bidirectional DC/DC converters and bidirectional AC/DC inverters in the inverter unit are connected to the first circuit breaker in the fuel cell test unit and the second circuit breaker in the energy storage unit respectively through low-voltage signal lines The circuit breaker, the third circuit breaker in the lithium-ion battery into a capacity unit, the voltage and current Hall sensor of the DC bus L1, and the grid-connected isolation switch of the inverter unit are connected. 8. A control method for a microgrid-based battery-forming capacitive coupling system, characterized in that the method is realized by the following steps: In step (1), the energy management unit starts a self-check and confirms that the grid-connected isolation switch of the inverter unit is in a disconnected state, so that the fuel cell test and the lithium-ion battery into a capacitive coupling system enter the initial off-grid control mode ; In step (2), the energy management unit determines the total amount of electricity Q ₁ generated by the fuel cell in the entire testing process through the fuel cell testing unit, and the energy storage unit determines that the energy storage battery pack is discharged from the current SOC to the set value. The dischargeable capacity Q ₂ when the SOC is at the lower limit and the chargeable capacity Q′ ₂ when the current SOC is charged to the set SOC upper limit are determined by the lithium-ion battery formation and capacity unit to determine the formation and/or capacity division of the lithium-ion battery cells. The total capacity Q ₃ to be charged; according to the magnitude relationship of Q ₁ , Q ₂ , Q′ ₂ and Q ₃ , it is determined to enter the steady-state off-grid working mode, namely step (3), or the transient grid-connected working mode, namely step (4); In step (3), the energy management unit starts the fuel cell test unit to test the electrochemical performance of the fuel cell to be tested, and starts the lithium-ion battery compositing unit to charge and discharge the lithium-ion battery cells that have entered the chemical compositing process, The grid-connected isolating switch of the inverter unit is always in an off state, wherein the energy management unit obtains the power Q _F generated by the fuel cell during the test process and the power required for charging the lithium-ion battery cell into a capacitor in real time. Q _C and the amount of electricity Q _D generated by discharge; In step (4), the energy management unit starts the fuel cell test unit to perform an electrochemical performance test on the fuel cell to be tested, and starts the lithium ion battery compositing unit to charge and discharge the lithium ion battery cells that have entered the chemical compositing process, The energy management unit acquires, in real time, the amount of electricity Q _F generated by the fuel cell during the test, the state of charge SOC of the energy storage battery pack in the energy storage unit, and the amount of electricity Q _C required for charging the lithium-ion battery cells into components and the amount of electricity Q _D produced by the discharge. 9 . The control method for a microgrid-based battery-based capacitive coupling system according to claim 8 , wherein in the step (3), when it is detected that Q _F < Q _C or Q _F =0, that is, the fuel When the battery is not electrochemically tested, the energy management unit sends a turn-on command to the first bidirectional DC/DC converter and the second circuit breaker in the energy storage unit, which is merged into the DC bus L1, and the electrical energy stored in the energy storage battery pack is passed through. The first bidirectional DC/DC converter is converted into a voltage matching the DC bus L1 and then sent to the DC bus L1; when it is detected that Q _F ≥ Q _C or Q _D ≥ 0, that is, the lithium-ion battery cell is in the discharge step or static state. When set, the energy management unit sends a turn-on command to the first bidirectional DC/DC converter and the second circuit breaker in the energy storage unit to merge into the DC bus L1 to convert the surplus electric energy of the DC bus L1 through the first bidirectional DC/DC The converter converts it into a voltage that matches the charging voltage of the energy storage battery pack and then outputs it to the energy storage battery pack. 10 . The method for controlling a microgrid-based battery-based capacitive coupling system according to claim 8 , wherein in the step (4), when it is detected that Q _F < Q _C or Q _F =0 That is, when the fuel cell is not electrochemically tested, the energy management unit transfers the electrical energy stored in the energy storage battery pack in the energy storage unit via the first energy storage unit under the condition that the grid-connected isolation switch in the inverter unit is kept disconnected. The bidirectional DC/DC converter is converted into a voltage matching the DC bus L1 and then sent to the DC bus L1 to supplement the electric energy for the lithium-ion battery cells in the charging step. When the energy management unit detects the energy storage in the energy storage unit When the state of charge (SOC) of the battery pack has dropped to the set lower limit, and the lithium-ion battery cells in the process of converting into capacity still need to be charged, the grid-connected isolation switch of the inverter unit is closed, and the electric energy of the external grid is passed through the bidirectional AC/DC. The inverter converts the DC voltage that matches the DC bus L1 into the DC bus L1 to supply power for the lithium-ion battery cells being charged; when it is detected that Q _F ≥ Q _C or Q _D ≥ 0, the lithium-ion battery cells are When in the discharge step or at rest, the energy management unit switches the DC bus L1 according to the voltage and current fluctuations of the DC bus L1 monitored in real time under the condition that the grid-connected isolation switch in the inverter unit is kept disconnected. The surplus electric energy in the energy storage unit is converted into a voltage matching the charging voltage of the energy storage battery pack through the first bidirectional DC/DC converter in the energy storage unit, and then output to the energy storage battery pack, and when the energy management unit detects that the energy storage battery The state of charge SOC of the group has risen to the set upper limit while the fuel cell test is still in progress and/or the lithium-ion battery cells are still discharging or standing still. The electric energy is converted into the specified AC voltage by the bidirectional AC/DC inverter of the inverter unit and then sent to the external power grid to ensure the orderly and stable operation of the fuel cell test and the lithium-ion battery composition.

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