CN111446467A

CN111446467A - Fuel cell cogeneration system and control method thereof

Info

Publication number: CN111446467A
Application number: CN202010227314.0A
Authority: CN
Inventors: 吴炎花; 郝传璞; 陈建平; 徐吉林; 李然
Original assignee: Shanghai Electric Group Corp
Current assignee: Shanghai Electric Group Corp
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2020-07-24
Anticipated expiration: 2040-03-27
Also published as: CN111446467B

Abstract

The invention discloses a fuel cell cogeneration system and a control method thereof, belonging to the technical field of fuel cell cogeneration. The fuel cell cogeneration system comprises a control module, a galvanic pile, a first power device, a reversing device, a heat exchange device, a heat dissipation device, a second power device and a heat storage device. The fuel cell cogeneration control system is provided with three liquid paths, namely a heat exchange liquid path, a heat dissipation liquid path and a heat storage liquid path, so that the heat storage liquid path and the heat exchange liquid path generate heat exchange, the heat dissipation liquid path dissipates heat to cooling liquid, the flow of the heat exchange liquid path and the flow of the heat dissipation liquid path are adjusted in a closed loop mode through the reversing device, the stacking temperature of the cooling liquid is finely controlled, and the accuracy and the stability of the stacking temperature are improved.

Description

Fuel cell cogeneration system and control method thereof

Technical Field

The invention relates to a fuel cell cogeneration technology, in particular to a fuel cell cogeneration system and a control method thereof.

Background

The fuel cell generates electricity by adopting the electrochemical reaction of hydrogen and oxygen, and heat is generated in the electricity generation process, wherein the electricity generation is carried out in the electric pile, and the generated heat is taken out of the electric pile through a medium. The electric efficiency range of the fuel cell is 35-55%, and if the rest heat energy can be recovered through a proper heat exchange mode, the total efficiency of the fuel cell can be improved; the system combining the fuel cell and the heat exchange mode is the fuel cell cogeneration system.

The fuel cell has higher requirement on the operation temperature, and the control mode, the heat exchange mode and the joint control mode of the fuel cell influence the accuracy and the stability of the operation temperature of the fuel cell. In the prior art, heat energy is recovered by setting a heat storage device and a heat exchanger, so that the heat storage device and a fuel cell exchange heat with a medium of the fuel cell at the heat exchanger, and the pile entering temperature of the fuel cell is regulated and controlled by adjusting the flow and the flow speed of hot water in the heat storage device, however, the temperature of the hot water before and after heat exchange is greatly influenced by the flow, and the control accuracy and the stability of the pile entering temperature are poor.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a fuel cell cogeneration system and a control method thereof.

The invention solves the technical problems through the following technical scheme:

a fuel cell cogeneration system is characterized by comprising a control module, a galvanic pile, a first power device, a reversing device, a heat exchange device, a heat dissipation device, a heat storage device and a second power device; the electric pile comprises a pile inlet and a pile outlet;

the reactor outlet, the first power device, the reversing device, the heat exchange device and the reactor inlet are communicated in sequence to form a heat exchange liquid path for heat exchange of cooling liquid;

the stack outlet, the first power device, the reversing device, the heat dissipation device and the stack inlet are sequentially communicated to form a heat dissipation liquid path for dissipating heat of cooling liquid;

the cold end of the heat storage device, the second power device, the heat exchange device and the hot end of the heat storage device are sequentially communicated to form a heat storage liquid path for heat exchange between the hot water and the heat exchange liquid path;

the control module is used for adjusting the mixing proportion of the cooling water in the heat exchange liquid path and the heat dissipation liquid path through the reversing device to control the reactor inlet temperature when the cooling liquid enters the reactor inlet in a closed-loop mode.

In this scheme, two confession coolant liquid circulations are in order to the return circuit to its control by temperature change to fuel cell part has set up two confession coolant liquid ways and heat-dissipating liquid way, and these two liquid ways all can realize the control by temperature change to the coolant liquid, through the flow on switching-over device closed loop regulation heat-transferring liquid way and heat-dissipating liquid way, realize the meticulous control to the income heap temperature of coolant liquid to the precision and the stability of the control of income heap temperature have been improved.

Preferably, the reversing device comprises a three-way regulating valve, and the control module is specifically configured to control a mixing ratio of the cooling liquids in the two liquid paths when the heat-radiating liquid path and the heat-exchanging liquid path operate simultaneously by regulating an opening degree of the three-way regulating valve; when the opening of the three-way regulating valve is 0%, the heat exchange liquid path is completely opened, and the heat dissipation liquid path is closed; when the opening of the three-way regulating valve is 100%, the heat exchange liquid path is closed, and the heat dissipation liquid path is completely opened.

Preferably, the heat dissipating device includes a heat dissipating fan for dissipating heat from the coolant; the control module is also used for controlling the temperature of the cooling liquid in the cooling liquid path by adjusting the rotating speed of the cooling fan.

Preferably, the fuel cell cogeneration system further comprises a hydrogen device, an air device and an inverter; the control module is also used for controlling the hydrogen device to supply hydrogen to the galvanic pile, controlling the air device to supply air to the galvanic pile, and controlling the inverter to feed the electric quantity generated by the galvanic pile back to the power grid.

A control method of a fuel cell cogeneration system, characterized in that the control method is used for controlling the fuel cell cogeneration system as described above;

the control method comprises the following steps:

s10, controlling the heat exchange liquid path, the heat dissipation liquid path and the heat storage liquid path to operate;

and S20, controlling the reactor temperature within a target temperature range by adjusting the mixing ratio of the cooling liquid in the heat exchange liquid path and the cooling liquid in the heat dissipation liquid path in a closed loop manner.

Preferably, the reversing device comprises a three-way regulating valve, and the control module is specifically configured to control a mixing ratio of the cooling liquids in the two liquid paths when the heat-radiating liquid path and the heat-exchanging liquid path operate simultaneously by regulating an opening degree of the three-way regulating valve; when the opening of the three-way regulating valve is 0%, the heat exchange liquid path is completely opened, and the heat dissipation liquid path is closed; when the opening of the three-way regulating valve is 100%, the heat exchange liquid path is closed, and the heat dissipation liquid path is completely opened;

step S20 specifically includes the following steps:

and S21, controlling the reactor temperature within the target temperature range by regulating the opening of the three-way regulating valve through PID.

Preferably, in step S21, the stack is further controlled to operate at the first power.

Preferably, the heat dissipating device includes a heat dissipating fan for dissipating heat from the coolant; the control module is also used for controlling the temperature of the cooling liquid in the cooling liquid path by adjusting the rotating speed of the cooling fan;

the control method further includes the following steps after step S20:

and S30, controlling the stack temperature to be within the target temperature range by adjusting the rotating speed of the cooling fan through PID.

Preferably, in step S30, the stack is further controlled to operate at the first power.

Preferably, the following steps are further included between step S21 and step S30:

s22, judging whether the stacking temperature is larger than a first temperature threshold value or not, and whether the opening degree of the three-way regulating valve is larger than a first opening degree threshold value or not, if so, executing a step S30, and otherwise, repeating the step S22.

Preferably, the control method further includes the following step before step S10:

and S09, controlling the heat exchange liquid path and the heat storage liquid path to operate, and disconnecting the heat dissipation liquid path, and controlling the stacking temperature within the target temperature range by adjusting the flow rate of the heat storage liquid path.

Preferably, step S09 specifically includes:

s091, controlling the opening of the three-way regulating valve to be 0%, and controlling the first power device to operate;

and S092, controlling the second power device to operate, and regulating the rotating speed of the second power device through PID to control the reactor temperature to be within the target temperature range.

Preferably, the following steps are further included between step S091 and step S092:

and S0911, controlling the first power device to operate at a first rotating speed, and controlling the electric pile to operate at a second power, wherein the second power is greater than the first power.

Preferably, step S09 further includes the following steps after step S092:

s093, judging whether the stacking temperature of the cooling liquid is greater than the first temperature threshold and whether the water temperature of the hot water is greater than a second temperature threshold, if so, executing the step S10, otherwise, returning to the step S092; wherein the first temperature threshold is greater than the second temperature threshold.

Preferably, the control method further includes the following step after step S30:

s40, judging whether the water temperature of the hot water is smaller than a third temperature threshold, if so, returning to the step S092, otherwise, executing the step S50; wherein the third temperature threshold is less than the second temperature threshold;

and S50, judging whether a shutdown instruction exists, if so, closing the galvanic pile, otherwise, returning to the step S30.

Preferably, the control method further includes the following step before step S09:

s081, judging whether the stacking temperature of the cooling water is less than the lowest temperature of the target temperature range, if so, executing a step S082, otherwise, executing a step S091;

s082, controlling the opening of the three-way regulating valve to be 0% and controlling the heat storage liquid path to be closed;

s083, controlling the first power device to operate at the second rotating speed, operating the electric pile at the third power, and returning to the step S081; wherein the second rotation speed is less than the first rotation speed, and the third power is less than the first power.

Preferably, the control method further includes the following step before step S08:

s071, receiving a starting-up instruction;

s072, judging whether the temperature of the hot water is lower than the third temperature threshold, if so, executing the step S081 after starting the electric pile, otherwise, returning to the step S071.

Preferably, the fuel cell cogeneration system further comprises a hydrogen device, an air device and an inverter; the control module is also used for controlling the hydrogen device to supply hydrogen to the galvanic pile, controlling the air device to supply air to the galvanic pile and controlling the inverter to feed the electric quantity generated by the galvanic pile back to the power grid;

the starting electric pile comprises the following steps:

s073, controlling the hydrogen device to supply hydrogen to the galvanic pile, and controlling the air device to supply air to the galvanic pile;

and S074, judging whether the voltage of the galvanic pile is established, if so, controlling the inverter to feed back the electric quantity to the power grid, otherwise, returning to the step S073.

On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The positive progress effects of the invention are as follows:

according to the fuel cell cogeneration system, the three liquid paths of the heat exchange liquid path, the heat dissipation liquid path and the heat storage liquid path are arranged, the flow rates of the heat exchange liquid path and the heat dissipation liquid path are adjusted in a closed loop mode through the reversing device, the fine control of the stacking temperature of the cooling liquid is realized, and the accuracy and the stability of the control of the stacking temperature are improved.

The control method of the fuel cell cogeneration control system realizes accurate control of the reactor temperature by closed-loop regulation of the flow of the cooling liquid in the heat exchange liquid path and the cooling liquid path, thereby improving the accuracy and stability of the control of the reactor temperature.

Drawings

Fig. 1 is a fluid circuit diagram of a fuel cell cogeneration system according to an embodiment of the invention;

FIG. 2 is a gas diagram of a hydrogen plant according to an embodiment of the present invention;

FIG. 3 is a gas path diagram of an air device according to an embodiment of the present invention;

FIG. 4 is a schematic block diagram of a fuel cell cogeneration system according to one embodiment of the invention;

fig. 5 is a flowchart of a control method of a fuel cell cogeneration system according to an embodiment of the invention.

Description of reference numerals:

electric pile 10

Pile inlet 101

Discharge port 102

First power unit 20

Reversing device 30

First water inlet 301

First water outlet 302

Second water outlet 303

Heat exchange device 40

Heat sink 50

A second power unit 60

Heat storage device 70

Control module 80

Hydrogen device 90

Hydrogen storage tank 901

Pressure reducing proportional valve 902

Hydrogen circulation pump 903

Hydrogen tail valve 904

Air device 100

Air compressor 1001

Humidifier 1002

Inverter 110

Temperature sensor 120

Heat storage module 130

Detailed Description

The present invention is further illustrated by the following examples, but is not limited thereby in the scope of the examples described below.

Referring to fig. 1-4, an embodiment of the invention provides a fuel cell cogeneration system for recovering heat generated in a fuel cell power generation process to realize cogeneration.

The fuel cell cogeneration system comprises a control module 80, a stack 10, a first power device 20, a reversing device 30, a heat exchange device 40, a heat dissipation device 50, a second power device 60 and a heat storage device 70, wherein the stack 10 comprises a stack inlet 101 and a stack outlet 102.

The electric pile 10 has a cooling liquid therein for absorbing and taking away heat generated by the electric pile 10 during operation, the cooling liquid naturally dissipates heat, exchanges heat and/or dissipates heat outside the electric pile 10 and then flows back into the electric pile 10, a pile inlet 101 of the electric pile 10 is used for the inflow of the cooling liquid, and a pile outlet 102 of the electric pile 10 is used for the outflow of the cooling liquid. Controlling the stack temperature of the cooling fluid entering the stack inlet 101 within a suitable range ensures that the stack 10 operates at a preferred ambient temperature, wherein the stack temperature can be measured by the temperature sensor 120 and fed back to the control module 80.

The first power device 20 provides power for circulation of the cooling liquid, and is preferably arranged close to the inlet 101 of the electric pile 10 so as to draw the cooling liquid out of the electric pile 10; the start and stop of the first power plant 20 is controlled via a control module 80.

The reversing device 30 is used for switching the liquid path and regulating the flow rate in the liquid path, and the action of the reversing device 30 is controlled by the control module 80.

The heat exchange device 40 is used for exchanging heat between the cooling liquid and the hot water in the heat storage module 130 so as to realize temperature control of the cooling liquid and/or the hot water; indeed, when only one of the cooling liquid and the hot water participates in circulation and flows through the heat exchanging device 40, the heat exchanging device 40 only serves as a circulation channel; the start and stop of the heat exchange device 40 is controlled by the control module 80.

The heat sink 50 is used for diffusing heat of the cooling liquid to the outside to cool the cooling liquid; the start and stop of the heat dissipation device 50 are controlled by the control module 80. The heat dissipation device 50 and the heat exchange device 40 are arranged in parallel; the control module 80 controls at least one of the heat sink 50 and the heat exchanger 40 to operate via the inverter 30.

The heat storage device 70 is used for accommodating hot water. The hot water flows out of the heat storage device 70, exchanges heat with the coolant at the heat exchange device 40, and then flows into the heat storage device 70. The heat storage device 70 is connected to the user side to replenish water for the user and to the municipal water supply system to replenish water from time to time.

The second power device 60 is used for providing power for hot water circulation, and preferably, the second power device 60 is arranged at a position close to the water outlet end of the heat storage device 70; the start and stop of the second power plant 60 is controlled via a control module 80.

The control module 80 employs, for example, an ECU (electronic control unit).

In this embodiment, the fuel cell cogeneration system forms three liquid paths through the stack 10, the first power device 20, the reversing device 30, the heat exchanging device 40, the heat dissipating device 50, the heat storage device 70, and the second power device 60, and the three liquid paths are respectively:

a heat exchange liquid path for cooling liquid heat exchange formed by sequentially communicating the reactor outlet 102, the first power device 20, the reversing device 30, the heat exchange device 40 and the reactor inlet 101;

a heat dissipation liquid path for dissipating heat of the cooling liquid is formed by sequentially communicating the stack outlet 102, the first power device 20, the reversing device 30, the heat dissipation device 50 and the stack inlet 101; and the number of the first and second groups,

and the cold end of the heat storage device 70, the second power device 60, the heat exchange device 40 and the hot end of the heat storage device 70 are sequentially communicated to form a heat storage liquid path for heat exchange between the hot water and the heat exchange liquid path.

The heat exchange liquid path and the heat dissipation liquid path can cool the cooling liquid; when the heat exchange liquid path is used for cooling the cooling liquid, the heat exchange liquid path exchanges heat with the hot water and simultaneously realizes the heating effect of the hot water so as to cool the cooling liquid, and the cooling amplitude of the cooling liquid is relatively small; the heat dissipation liquid path is used for diffusing the heat energy of the cooling liquid to the outside, and the cooling amplitude of the cooling liquid is relatively large. In other words, when the heat exchange liquid path is used for cooling the cooling liquid, the heat exchange liquid path and the heat dissipation liquid path have different cooling effects on the same cooling liquid based on different working modes.

The heat exchange liquid path and the heat dissipation liquid path can be operated independently or simultaneously. When the two liquid paths run simultaneously, the control module 80 adjusts the mixing ratio of the cooling water in the two liquid paths through the reversing device 30 to perform closed-loop control on the stacking temperature of the cooling liquid.

Therefore, the fuel cell cogeneration system of the embodiment of the invention is provided with three liquid paths, namely the heat exchange liquid path, the heat dissipation liquid path and the heat storage liquid, and the reversing device 30 is used for adjusting the flow rates of the heat exchange liquid path and the heat dissipation liquid path in a closed loop manner, so that the fine control of the stacking temperature of the cooling liquid is realized, and the accuracy and the stability of the control of the stacking temperature are improved.

Referring to fig. 1, in the example of the present invention, the reversing device 30 includes a three-way regulating valve, and the control module 80 is specifically configured to control a mixing ratio of the cooling liquids in the two liquid paths when the heat-dissipating liquid path and the heat-exchanging liquid path operate simultaneously by regulating an opening degree of the three-way regulating valve; when the opening of the three-way regulating valve is 0%, the heat exchange liquid path is completely opened, and the heat dissipation liquid path is completely closed; when the opening of the three-way regulating valve is 100%, the heat exchange liquid path is closed, and the heat dissipation liquid path is completely opened.

The three-way regulating valve comprises a first water inlet, a first water outlet 302 and a second water outlet 303, the first water inlet is communicated with the first power device 20, the first water outlet 302 is communicated with the heat exchange device 40, and the second water outlet 303 is communicated with the heat dissipation device 50; when the opening degree of the three-way regulating valve is 0%, the first water outlet 302 is completely communicated with the first water inlet, and when the opening degree of the three-way regulating valve is 100%, the second water outlet 303 is completely communicated with the first water inlet; when the opening degree of the three-way regulating valve is between 0% and 100% (excluding end point values), the first water outlet 302 is communicated with the first water inlet, and the second water outlet 303 is communicated with the first water inlet; the opening degree of the three-way control valve is inversely proportional to the flow rate of the coolant flowing to the heat exchanging device 40 and directly proportional to the flow rate of the coolant flowing to the heat radiating device 50.

Continuing to refer to fig. 1, in an example of the present invention, the heat dissipation device 50 includes a heat dissipation fan for dissipating heat from the cooling fluid; the control module 80 is also configured to control the temperature of the cooling fluid in the cooling fluid path by adjusting the rotational speed of the cooling fan.

The control module 80 preferably controls the temperature of the cooling fluid by controlling the rotation speed of the cooling fan in a closed loop.

With continued reference to fig. 2-4, in the exemplary embodiment of the present invention, the fuel cell cogeneration system further includes a hydrogen device 90, an air device 100, and an inverter 110; the control module 80 is also used for controlling the hydrogen device 90 to supply hydrogen to the stack 10, controlling the air device 100 to supply air to the stack 10, and controlling the inverter 110 to feed the electricity generated by the stack 10 back to the power grid.

As shown in fig. 2, the hydrogen device 90 includes a hydrogen storage tank 901, a pressure reduction proportional valve 902, a hydrogen circulation pump 903, and a hydrogen tail valve 904. The hydrogen storage tank 901 stores hydrogen gas; the control module 80 regulates the supply of hydrogen into the stack 10 through the pressure reducing proportional valve 902; the hydrogen gas which is in excess reaction in the electric pile 10 is discharged out of the electric pile 10 and then is discharged out of the fuel cell cogeneration system through a hydrogen tail discharge valve 904, or is pumped into the electric pile 10 again through a hydrogen circulating pump 903 for recycling.

As shown in fig. 3, the air device 100 includes an air compressor 1001 and a humidifier 1002, and the air is compressed by the air compressor 1001, enters the humidifier 1002 to adjust the humidity suitable for the operation of the stack 10, and then enters the stack 10. The air excess in the stack 10 may flow back into the humidifier 1002 again to adjust humidity for reuse, and in addition, the humidifier 1002 may have other interfaces connected to an external structure.

As shown in fig. 4, the hydrogen device 90, the air device 100, the DC/AC (inverter 110) and the heat storage module 130 are controlled by the stack 10 module, wherein the heat storage module 130 is understood as a general term for the components of the heat storage portion, and the heat storage module 130 may have different divisions under different standards, for example, in the example shown in fig. 4, the heat storage module 130 includes the heat storage device 70 and the second power device 60.

Embodiments of the present invention also provide a control method of a fuel cell cogeneration system, the control method being used for controlling the fuel cell cogeneration control system as described in any of the above examples.

Referring to fig. 1-5, the control method includes the following steps:

s071, receiving a starting-up instruction; the starting-up instruction is sent out through the user side, for example, the action of opening the water heater by the user triggers the starting-up instruction;

s072, judging whether the temperature of the hot water is lower than a third temperature threshold, if so, executing a step S081 after starting the electric pile 10, otherwise, returning to the step S071; a third temperature threshold is preset in the control module 80, and the hot water at the third temperature threshold meets the heat demand of the user to a certain extent, for example, the third temperature threshold is 45 ℃;

wherein, starting the galvanic pile 10 comprises the following steps:

s073, controlling the hydrogen device 90 to supply hydrogen to the stack 10, and controlling the air device 100 to supply air to the stack 10;

s074, determining whether the voltage of the stack 10 is established, if so, controlling the inverter 110 to feed back the electric quantity to the grid, otherwise, returning to step S073, in other words, controlling the hydrogen device 90 and the air device 100 to stop supplying the corresponding gas to the stack 10 until the voltage of the stack 10 is established.

Referring to fig. 5, after the inverter 110 generates power and feeds the grid, the following steps are continued:

s081, judging whether the reactor temperature of the cooling water is less than the lowest temperature of the target temperature range, if so, executing a step S082, otherwise, executing a step S091; the target temperature range is set according to the requirement of the galvanic pile 10 on the operating temperature, the operating efficiency of the galvanic pile 10 in a certain temperature range is relatively high, and the certain temperature range is the target temperature range; it should be noted that the target temperature range differs from stack 10 to stack 10, for example, in one example, the target temperature range is 59 ℃ to 61 ℃, and in another example, the target temperature range is 55 ℃ to 60 ℃, both examples being possible; in addition, it is preferable that the third temperature threshold is smaller than the lowest temperature of the target temperature range;

s083, controlling the first circulating pump to operate at the second rotating speed, operating the galvanic pile 10 at the third power, and returning to the step S081; wherein, the second rotating speed is preferably a certain rotating speed below the rated rotating speed of the first circulating pump, for example, the rated rotating speed is 4000r/min, and the second rotating speed is 2000 r/min; preferably, the third power is a power lower than the idle power of the stack 10.

Here, step S082 and step S083 are further explained: when the stacking temperature is lower than the target temperature in step S081, step S082 and step S083 are first executed to heat the coolant, and after the temperature of the coolant reaches the target temperature range, the electric stack 10 can heat the hot water in a better operation state, thereby implementing fine control of the fuel cell cogeneration system and improving the working efficiency thereof. In addition, in step S082 and step S083, the first circulating pump is controlled to operate at the first rotating speed, so that on one hand, the loss of natural heat dissipation of the cooling liquid in the circulating process is reduced, and on the other hand, the uniformity of the temperature of each part in the stack 10 is ensured by the circulating cooling liquid; the galvanic pile 10 is controlled to operate at the third power, so that the problem that the galvanic pile 10 is damaged due to direct high-power operation at a lower temperature is solved, and the stability and the reliability of the operation of the galvanic pile 10 are ensured.

Referring to fig. 5, if the step S081 is negative, the following steps are continued:

s09, controlling the heat exchange liquid path and the heat storage liquid path to operate, and disconnecting the heat dissipation liquid path, and controlling the stacking temperature within a target temperature range by adjusting the flow rate of the heat storage liquid path; the hot water starts to be heated at this stage, the heat exchange liquid path and the hot water storage path exchange heat at the heat exchange device 40, specifically, the hot water is heated by the cooling liquid, and the hot water acts on the cooling liquid and is controlled within a target temperature range.

Since step S09 is specifically implemented by the following steps, step S09 is identified in fig. 5:

s091, controlling the opening of the three-way regulating valve to be 0%, and controlling the first circulating pump to operate to enable the cooling liquid to circulate in the heat exchange liquid path; if the heat exchange liquid path is already operated when the step is carried out, the state of each part on the heat exchange liquid path is controlled to be kept in the step;

s0911, controlling the first circulating pump to operate at a first rotating speed, and controlling the galvanic pile 10 to operate at a second power, wherein the first rotating speed is greater than the second rotating speed, and preferably the first rotating speed is the rated rotating speed of the first circulating pump; the second power is higher than the third power, and preferably, the second power is the rated power of the stack 10.

And S092, controlling the second circulating pump to operate, enabling the heat storage liquid path to operate, and adjusting the rotating speed of the second circulating pump through PID to control the water temperature to be within the target temperature range.

S093, judging whether the stacking temperature of the cooling liquid is greater than a first temperature threshold value or not, and whether the water temperature of the hot water is greater than a second temperature threshold value or not, if so, executing the step S20 after executing the step S10, otherwise, returning to the step S092; wherein the first temperature threshold is preferably greater than the upper limit of the target temperature range; preferably, the second temperature threshold is less than the lower limit of the target temperature and greater than the third temperature threshold mentioned above, for example, when the target temperature range is 59 ℃ to 61 ℃, the first temperature threshold is 62 ℃, the second temperature threshold is 55 ℃, and the third temperature threshold is 45 ℃.

The specific steps of step S09 have been described above. When the coolant reaches the target temperature range, the coolant proceeds to step S09, and at this stage, the hot water is stored such that the temperature of the coolant in the stack is maintained within the target temperature range, and the temperature of the hot water is raised.

S10, controlling the heat exchange liquid path, the heat dissipation liquid path and the heat storage liquid path to operate; the heat exchange liquid path and the heat storage liquid path exchange heat at the heat exchange device 40, the heat dissipation liquid path dissipates heat of the cooling liquid through the heat dissipation device 50, and cooling water in the heat exchange liquid path and the heat dissipation liquid path flows into the electric pile 10 after being converged; in step S093, the heat exchange liquid path, the heat dissipation liquid path, and the heat storage liquid path are already substantially in an operating state, so in this step, the three-way regulating valve, the first circulating pump, the second circulating pump, and the stack are only required to be in a state, and step S10 is not shown in the flowchart illustrated in fig. 5.

S20, controlling the temperature of the reactor in the target temperature range by adjusting the mixing ratio of the cooling liquid in the heat exchange liquid path and the heat dissipation liquid path in a closed loop manner, wherein the step S20 is realized by the following steps, and correspondingly, the step S20 is not separately listed in FIG. 5:

s21, controlling the stacking temperature within a target temperature range by regulating the opening of the three-way regulating valve through PID; when the reactor inlet temperature exceeds a target temperature range or approaches the upper limit of the target temperature range, the opening degree of the three-way regulating valve is increased, so that the ratio of cooling liquid in the cooling liquid path is larger; when the reactor entering temperature is lower than the target temperature range or is close to the lower limit of the target temperature range, the opening degree of the three-way regulating valve is reduced, so that the ratio of the cooling liquid in the heat exchange liquid path is larger.

In step S21, the stack 10 is further controlled to operate at a first power, wherein the first power is greater than the third power and less than the second power, and preferably the first power is an idle power set for the stack 10 when the stack 10 is designed.

S22, judging whether the stacking temperature is larger than a first temperature threshold value or not and whether the opening degree of the three-way regulating valve is larger than a first opening degree threshold value or not, if so, controlling the opening degree of the three-way regulating valve to be unchanged and executing the step S30, otherwise, repeating the step S22; the first temperature threshold is a preset temperature, preferably the first temperature threshold is larger than the upper limit of the target temperature range, and the first temperature threshold is larger than the second temperature threshold; the first opening degree threshold is preferably 90%.

S30, controlling the stacking temperature by adjusting the rotating speed of the cooling fan through PID; when the reactor entering temperature exceeds or approaches the upper limit of the target temperature range, the rotating speed of the cooling fan is increased; and when the stacking temperature is lower than or close to the lower limit of the target temperature range, the rotating speed of the cooling fan is reduced.

It is preferable to control the stack 10 to operate at the first power in step S30.

And S40, judging whether the water temperature of the hot water is less than a third temperature threshold, if so, returning to the step S092, otherwise, executing the step S50.

S50, judging whether a shutdown instruction exists, if so, closing the galvanic pile 10, otherwise, returning to the step S30; wherein shutting down the stack 10 is understood to control the hydrogen device 90 to no longer supply hydrogen, the air device 100 to no longer supply air, and the inverter 110 to stop operating.

As can be seen from the above, the control method according to the embodiment of the present invention has at least the following technical effects:

firstly, the flow rates of a heat exchange liquid path and a heat dissipation liquid path are adjusted in a closed loop mode through a reversing device 30, so that the stacking temperature of cooling liquid is finely controlled, and the accuracy and the stability of the stacking temperature control are improved;

secondly, the control method is provided with a plurality of temperature control stages: a step of heating the cooling liquid through the steps S082 and S083, a step of rapidly heating the hot water through the step S09, a step of slowly heating the hot water and simultaneously radiating the cooling liquid through the step S20, and a step of radiating the cooling liquid through the step S30; the stages are arranged to control the fuel cell cogeneration system in detail, and the production efficiency of the system is improved through fine control;

thirdly, the running power of the galvanic pile 10 is set to be in three grades, the galvanic pile 10 is controlled to match the appropriate power in different stages, and the accuracy and the stability of the control of the temperature of the galvanic pile are improved.

The control method of the present invention is further illustrated by taking a specific application condition as follows:

the fuel cell cogeneration system is used for a household building (small building 4-8 households), the rated power of a galvanic pile 10 is 5kw, a heat storage device 70 is a water tank, the capacity of 2000L is selected, DC/AC is connected to the grid to supply power to household appliances, the water tank supplies heat to household hot water, the preset target temperature range is 59-61 ℃, the first temperature threshold is 62 ℃, the second temperature threshold is 55 ℃, the third temperature threshold is 45 ℃, the first rotating speed is 4000r/min, the second rotating speed is 2000r/min, when a startup instruction is received, the temperature of the hot water is less than 45 ℃, a switch is turned on, and the fuel cell cogeneration system starts to operate:

the control module 80 controls the air compressor 1001 of the air device 100 to operate to supply air to the stack 10 and controls the hydrogen device 90 to operate to supply hydrogen to the stack 10;

after the voltage of the electric pile 10 is established, the control module 80 starts to control the DC/AC output electric power, when the circulating water temperature in the electric pile 10 is lower than a target temperature range, the fuel cell works at a third power of 2kw, and the rotating speed of the first circulating pump is set at a low rotating speed of 2000 r/min;

and after the reactor entering water temperature reaches the target temperature range, opening a second circulating pump, increasing the power of the galvanic pile 10 to the rated power, and controlling the reactor entering temperature to be 59-61 ℃ by performing real-time closed-loop regulation on the rotating speed of the second circulating pump according to the reactor entering temperature.

When the temperature of the heat storage water reaches a second temperature threshold value of 55 ℃ and the temperature of the reactor is higher than 62 ℃, controlling the heat exchange liquid path and the heat dissipation liquid path to run, controlling the temperature of the reactor to be in a target temperature range by adjusting the opening degree of a three-way adjusting valve through a PID (proportion integration differentiation), and reducing the power of the fuel cell to the idle power of 3kw, which is the first running power;

when the reactor inlet temperature is greater than a first temperature threshold value of 62 ℃ and the opening of the three-way regulating valve is greater than 90%, the rotating speed of the PID regulating fan controls the reactor inlet temperature to keep a target temperature range, and the electric reactor 10 is controlled to operate at a first power;

when the user uses water to reduce the temperature of the hot water to below 45 ℃, returning to the step of PID (proportion integration differentiation) to adjust the rotating speed of the second circulating pump to control the stacking temperature and then continuing to circulate;

when a shutdown instruction is received, the control module 80 controls the DC/AC to stop working, and the air device 100 and the hydrogen device 90 stop working; and reducing the temperature of the cooling water path to room temperature.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.

Claims

1. A fuel cell cogeneration system is characterized by comprising a control module, a galvanic pile, a first power device, a reversing device, a heat exchange device, a heat dissipation device, a heat storage device and a second power device; the electric pile comprises a pile inlet and a pile outlet;

2. The fuel cell cogeneration system of claim 1, wherein the reversing device comprises a three-way regulating valve, and the control module is specifically configured to control a mixing ratio of the cooling liquids in the two liquid paths when the heat-dissipating liquid path and the heat-exchanging liquid path operate simultaneously by adjusting an opening degree of the three-way regulating valve; when the opening of the three-way regulating valve is 0%, the heat exchange liquid path is completely opened, and the heat dissipation liquid path is closed; when the opening of the three-way regulating valve is 100%, the heat exchange liquid path is closed, and the heat dissipation liquid path is completely opened.

3. The fuel cell cogeneration system of claim 2, wherein said heat dissipating means comprises a heat dissipating fan for dissipating heat from the coolant; the control module is also used for controlling the temperature of the cooling liquid in the cooling liquid path by adjusting the rotating speed of the cooling fan.

4. The fuel cell cogeneration system of claim 3, further comprising a hydrogen plant, an air plant, and an inverter; the control module is also used for controlling the hydrogen device to supply hydrogen to the galvanic pile, controlling the air device to supply air to the galvanic pile, and controlling the inverter to feed the electric quantity generated by the galvanic pile back to the power grid.

5. A control method of a fuel cell cogeneration system, characterized by controlling the fuel cell cogeneration system according to claim 1;

the control method comprises the following steps:

6. The control method according to claim 5, wherein the reversing device comprises a three-way regulating valve, and the control module is specifically configured to control a mixing ratio of the cooling liquids in the two liquid paths when the heat-radiating liquid path and the heat-exchanging liquid path operate simultaneously by regulating an opening degree of the three-way regulating valve; when the opening of the three-way regulating valve is 0%, the heat exchange liquid path is completely opened, and the heat dissipation liquid path is closed; when the opening of the three-way regulating valve is 100%, the heat exchange liquid path is closed, and the heat dissipation liquid path is completely opened;

step S20 specifically includes the following steps:

7. The control method of claim 6, wherein in step S21, the stack is further controlled to operate at the first power.

8. The control method according to claim 7, wherein the heat dissipating means includes a heat dissipating fan for dissipating heat from the coolant; the control module is also used for controlling the temperature of the cooling liquid in the cooling liquid path by adjusting the rotating speed of the cooling fan;

the control method further includes the following steps after step S20:

9. The control method of claim 8, wherein in step S30, the stack is further controlled to operate at the first power.

10. The control method of claim 9, further comprising, between the step S21 and the step S30, the steps of:

11. The control method according to claim 10, characterized by further comprising, before step S10, the steps of:

12. The control method according to claim 11, wherein step S09 specifically includes:

13. The control method of claim 12, wherein between step S091 and step S092 further comprising the step of:

14. The control method according to claim 13, wherein step S09 further includes the following steps after step S092:

15. The control method according to claim 14, characterized by further comprising, after step S30, the steps of:

16. The control method according to claim 15, characterized by further comprising, before step S09, the step of:

17. The control method according to claim 16, characterized by further comprising, before step S08, the step of:

s071, receiving a starting-up instruction;

18. The control method according to claim 17, wherein the fuel cell cogeneration system further comprises a hydrogen device, an air device, and an inverter; the control module is also used for controlling the hydrogen device to supply hydrogen to the galvanic pile, controlling the air device to supply air to the galvanic pile and controlling the inverter to feed the electric quantity generated by the galvanic pile back to the power grid;

the starting electric pile comprises the following steps: