Hydrogen-electricity-storage coupling system and energy management method thereof

Abstract

The invention belongs to the technical field of hybrid energy storage, and particularly relates to a hydrogen-electricity-storage coupling system and an energy management method thereof. The hydrogen-electricity-storage coupling system comprises a wind generating set, a hydrogen energy storage device, a super capacitor and a user; the wind generating set, the hydrogen energy storage device and the super capacitor form an electric energy-hydrogen energy-electric energy closed-loop structure; the hydrogen energy storage device is used for playing an energy-type energy storage role to stabilize long-time electric power fluctuation and realize a peak clipping and valley filling target of a power grid; the super capacitor is used for playing a power type energy storage role to stabilize short-time electric power fluctuation and realize a power grid frequency modulation target; the hydrogen energy storage device comprises an electrolytic cell, a hydrogen storage tank and a fuel cell, and the electrolytic cell is connected with the fuel cell through the hydrogen storage tank; the wind generating set and the fuel cell are connected with the power grid and the storage unit through a direct-current bus. According to the invention, a cooperative working mode of the hydrogen energy storage device and the super capacitor under isolated island operation is introduced, and meanwhile, an energy management method corresponding to each working mode is formulated, so that cooperative work of each device of the hydrogen-electricity-storage coupling system is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of hybrid energy storage, and in particular relates to a hydrogen-electricity-storage coupling system and an energy management method thereof. Background Art

[0002] The current social demand for electricity is increasing, which has led to more and more attention paid to renewable energy power generation methods such as wind power and photovoltaics. However, due to its own fluctuating power generation characteristics, renewable energy will affect the safety and stability of the power grid, and easily cause a sharp drop in voltage or power grid collapse. In this regard, renewable energy local isolated grid power supply is often used, but due to the lack of large power grid support and power fluctuations, the system will face many difficulties in stability and reliability when operating in an isolated grid. Therefore, energy storage technology is used to solve the problems of system peak-to-valley differences and large-scale power consumption and release.

[0003] Hybrid energy storage composed of energy-type devices and power-type devices has the best power smoothing effect. The energy management strategy of hybrid energy storage has always been the focus and difficulty in energy storage systems. Energy storage elements are generally composed of energy-type elements such as battery packs and power-type elements such as supercapacitor groups. The energy storage elements achieve efficient charging and discharging, and improve the service life of the energy storage elements. These have always been difficult problems that need to be solved in hybrid energy storage research.

[0004] Therefore, it is necessary for the present application to provide a hydrogen-electricity-storage coupling system and an energy management method thereof to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art and to propose a hydrogen-electricity-storage coupling system and an energy management method thereof.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A hydrogen-electricity-storage coupling system, comprising a wind turbine generator set, a hydrogen energy storage device, a super capacitor and a user; the wind turbine generator set, the hydrogen energy storage device and the super capacitor form an energy closed loop structure of electric energy-hydrogen energy-electric energy;

[0008] The hydrogen energy storage device is used to play an energy storage role to smooth long-term power fluctuations and achieve the goal of peak shaving and valley filling in the power grid;

[0009] The supercapacitor is used to play a role in power-type energy storage to smooth short-term power fluctuations and achieve the goal of power grid frequency regulation;

[0010] The hydrogen energy storage device includes an electrolyzer, a hydrogen storage tank and a fuel cell. The electrolyzer is connected to the fuel cell through the hydrogen storage tank; the wind turbine generator set and the fuel cell are connected to the power grid and the storage unit through a DC bus, the wind turbine generator set is connected to the DC bus through an AC / DC step-down transformer, the DC bus is connected to the electrolyzer through a DC / DC step-down transformer, the fuel cell is connected to the DC bus through a DC / DC step-down transformer, the supercapacitor as a power-type energy storage device is connected to the DC bus through a DC / DC step-down transformer, and the DC bus is connected to the user through a DC / AC step-down transformer.

[0011] By adopting the above technical solution: the main function of the hydrogen energy storage device is to complete the energy conversion between electricity, hydrogen and electricity. When the wind power output is sufficient and there is excess user load, the electrolyzer is used to consume the excess wind power to produce hydrogen and realize the electricity-hydrogen conversion. The process has a fast adjustment speed and is highly adaptable to the unstable power output of the wind turbine. The generated hydrogen can be stored in the hydrogen storage device as a reaction product of the fuel cell; when the wind turbine output is insufficient to meet the user load, the fuel cell burns hydrogen to discharge.

[0012] Among them, both the AC / DC step-down transformer and the DC / DC step-down transformer help regulate the power flowing from the power supply into the DC bus and from the DC bus into the storage device. The DC side of the system controls the charging of the electrolyzer to produce hydrogen and the discharge of the fuel cell and supercapacitor. The AC side transmits the power supplemented by the fuel cell and supercapacitor to the grid side while maintaining the DC bus voltage stable, thereby achieving power peak and frequency regulation.

[0013] The present invention also provides an energy management method for a hydrogen-electricity-storage coupling system, such as Figure 2-Figure 3 As shown, the energy management method uses a hydrogen-electricity-storage coupling system to smooth the fluctuation between wind power load and user load, including the following operation modes:

[0014] Mode S1: The electrolyzer operates normally, the fuel cell and supercapacitor are shut down, the wind turbine generator set abandons wind, and an external peak-shaving and frequency-regulating unit is required to increase output;

[0015] Mode S2: The electrolyzer operates at rated speed, the fuel cell is shut down, and the supercapacitor is charged;

[0016] Mode S3: The electrolyzer operates at rated speed, the fuel cell and supercapacitor are shut down, the wind turbine generator set abandons wind, and an external peak-shaving and frequency-regulating unit is required to increase output;

[0017] Mode S4: The electrolyzer operates at minimum output, the fuel cell is shut down, and the supercapacitor is discharged;

[0018] Mode S5: electrolyzer, fuel cell and supercapacitor are all shut down;

[0019] Mode S6: The electrolyzer is shut down, the fuel cell operates normally, and the supercapacitor is shut down;

[0020] Mode S7: The electrolyzer is shut down, the fuel cell is discharged at rated operation, and the supercapacitor is discharged;

[0021] Mode S8: electrolyzer shut down, fuel cell rated operation, supercapacitor shut down;

[0022] Mode S9: electrolyzer and fuel cell shut down, supercapacitor discharge;

[0023] Mode S10: The electrolyzer, fuel cell and supercapacitor are all shut down.

[0024] Furthermore, in the mode S1, the system needs to satisfy the following relationship:

[0025] P el-min ≤P W -P L ≤P el-max

[0026] in:

[0027] P el-min ——Minimum residual power of electrolyzer

[0028] P el-max ——The maximum residual power of the electrolyzer

[0029] P W ——Wind power output

[0030] P L ——User load

[0031] The remaining power of the electrolyzer is as follows:

[0032] P el =P W -P L

[0033] in:

[0034] P el ——Residual power of electrolyzer

[0035] The electrolyzer now acts as a buffer for excess wind power, while the fuel cell and supercapacitor are in shutdown mode;

[0036] In the mode S2, the system needs to satisfy the following relationship:

[0037]

[0038] in:

[0039] SOC——Supercapacitor Mode of Charge

[0040] SOC m-min ——Supercapacitor minimum charge mode

[0041] SOC m-max ——Supercapacitor maximum charge mode

[0042] The electrolyzer is in rated operation mode at this time, the excess wind power is used to charge the supercapacitor, and the fuel cell is in stop mode. The specific relationship is as follows:

[0043]

[0044] in:

[0045] P sc-ref ——Excess wind power supplies supercapacitor charging power

[0046] P fc ——Fuel cell power.

[0047] Furthermore, in the mode S3, the system needs to satisfy the following relationship:

[0048] or

[0049] The electrolyzer is in rated operation mode, and the supercapacitor and fuel cell are in shutdown mode. If the wind turbine generator set abandons wind, additional peak-shaving and frequency-regulating units need to be installed to maintain the power balance of the system. The specific relationship is as follows:

[0050]

[0051] in:

[0052] P sc ——Supercapacitor power.

[0053] Furthermore, in the mode S4, the system needs to satisfy the following relationship:

[0054]

[0055] The electrolyzer is running in the minimum output mode at this time, and the supercapacitor plays the role of compensating the power shortage of the system. During the discharge of the supercapacitor, the SOC mode continues to decrease until it drops to SOC min , the fuel cell is still in shutdown mode, the specific relationship is as follows:

[0056]

[0057] Furthermore, in the mode S5, the system needs to satisfy the following relationship:

[0058] or

[0059] The electrolyzer, fuel cell and supercapacitor are all shut down and running, and the specific relationship is as follows:

[0060]

[0061] In the mode S6, the system needs to satisfy the following relationship:

[0062] P fc-min ≤P L -P W ≤P fc-max

[0063] in:

[0064] P fc-min ——Maximum power of fuel cell

[0065] P fc-min ——Minimum fuel cell power

[0066] The electrolyzer is in shutdown mode, the fuel cell acts to compensate for the power difference of the system, and the supercapacitor is in shutdown mode. The specific relationship is as follows:

[0067]

[0068] Furthermore, in the mode S7, the system needs to satisfy the following relationship:

[0069]

[0070] The electrolyzer is in shutdown mode, the fuel cell is in rated mode, and the supercapacitor is discharged to make up for the power shortage of the system. The specific relationship is as follows:

[0071]

[0072] In the mode S8, the system needs to satisfy the following relationship:

[0073] or

[0074] The electrolyzer is in shutdown mode, the fuel cell is in rated mode, and the supercapacitor is in shutdown mode. The system needs to increase output to maintain power balance. The specific relationship is as follows:

[0075]

[0076] Furthermore, in the mode S9, the system needs to satisfy the following relationship:

[0077]

[0078] The electrolyzer is in shutdown mode, and the supercapacitor discharges to compensate for the power shortage of the system. During the discharge of the supercapacitor, the SOC continues to decrease until it drops to SOCmin. The fuel cell is in shutdown mode. The specific relationship is as follows:

[0079]

[0080] Furthermore, in the mode S10, the system needs to satisfy the following relationship:

[0081] or

[0082] The electrolyzer, fuel cell and supercapacitor are in shutdown mode, and the relationship is as follows:

[0083]

[0084] Furthermore, in mode S2, the supercapacitor charge mode SOC has a value range of 0.1-0.9, and the specific calculation formula is as follows:

[0085]

[0086] in:

[0087] |P s |——The absolute value of the system net load, which is the absolute value of the difference between wind power output power and user load

[0088] P sc-min ——Supercapacitor SC minimum power

[0089] P sc-max ——Maximum power of supercapacitor SC.

[0090] By adopting the above technical solution: wind turbines are selected to supply power to the isolated grid system, and in order to achieve "peak shaving and valley filling" of electricity, hydrogen energy storage devices are introduced as energy-type energy storage devices to absorb long-term power fluctuations to achieve power peak regulation; supercapacitors are introduced as power-type energy storage devices to absorb short-term power fluctuations to achieve frequency regulation, giving full play to the complementary advantages of the two. In order to verify the good effect of the hydrogen-electricity-storage coupling system of the present invention in smoothing power fluctuations, the collaborative working mode of the hydrogen energy storage device and the supercapacitor under isolated island operation is innovatively introduced. At the same time, energy management methods corresponding to each working mode are formulated to achieve the collaborative work of each device of the hydrogen-electricity-storage coupling system.

[0091] From the above, compared with the prior art, the present invention has the following beneficial effects:

[0092] 1. The present invention operates in an isolated island mode without the support of a large power grid. Taking into account the influence of wind power and load factors, a hydrogen-electricity-storage coupling system joint control method is proposed to ensure the stability of system voltage and frequency, so as to meet the needs of efficient utilization of wind, solar, water, hydrogen and electricity in an isolated island state.

[0093] 2. The energy management method of the present invention is to use a hydrogen-electricity-storage coupling system to smooth the fluctuations between wind power load and user load. The hydrogen energy storage device plays an energy-type energy storage role to smooth long-term power fluctuations and achieve the goal of peak shaving and valley filling of the power grid; the supercapacitor plays a power-type energy storage role to smooth short-term power fluctuations and achieve the goal of power grid frequency regulation. All devices constitute an energy closed-loop structure of electric energy-hydrogen energy-electric energy.

[0094] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description in combination with the preferred embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0096] Figure 1 It is a schematic diagram of the structure of the hydrogen-electricity-storage coupling system in the present invention;

[0097] Figure 2 A block diagram of an energy management method for a hydrogen-electricity-storage coupling system in the present invention;

[0098] Figure 3 The energy management process of the hybrid energy storage system when the hydrogen-electricity-storage coupling system in the present invention is working normally;

[0099] Figure 4 This is the energy management flow chart of Example 1 of the present invention;

[0100] Figure 5 This is the energy management flow chart of Example 2 of the present invention. DETAILED DESCRIPTION

[0101] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings, which is a part of this specification and illustrates the principles of the present invention through examples. Other aspects, features and advantages of the present invention will become clear from the detailed description. In the referenced drawings, the same or similar components in different figures are represented by the same reference numerals.

[0102] Reference Figure 1-Figure 5 , a hydrogen-electricity-storage coupling system, comprising a wind turbine, a hydrogen energy storage device, a supercapacitor and a user; the wind turbine, the hydrogen energy storage device and the supercapacitor constitute an energy closed loop structure of electric energy-hydrogen energy-electric energy;

[0103] The hydrogen energy storage device is used to play an energy storage role to smooth long-term power fluctuations and achieve the goal of peak shaving and valley filling in the power grid;

[0104] The supercapacitor is used to play a role in power-type energy storage to smooth short-term power fluctuations and achieve the goal of power grid frequency regulation;

[0105] The hydrogen energy storage device includes an electrolyzer, a hydrogen storage tank and a fuel cell. The electrolyzer is connected to the fuel cell through the hydrogen storage tank; the wind turbine generator set and the fuel cell are connected to the power grid and the storage unit through a DC bus, the wind turbine generator set is connected to the DC bus through an AC / DC step-down transformer, the DC bus is connected to the electrolyzer through a DC / DC step-down transformer, the fuel cell is connected to the DC bus through a DC / DC step-down transformer, the supercapacitor as a power-type energy storage device is connected to the DC bus through a DC / DC step-down transformer, and the DC bus is connected to the user through a DC / AC step-down transformer.

[0106] Among them, the main function of the hydrogen energy storage device is to complete the energy conversion between electricity, hydrogen and electricity. When the wind power output is sufficient and there is excess user load, the electrolyzer is used to consume the excess wind power to produce hydrogen and realize the electricity-hydrogen conversion. The process has a fast adjustment speed and is highly adaptable to the unstable power output of the wind turbine. The generated hydrogen can be stored in the hydrogen storage device as a reaction product of the fuel cell; when the wind turbine output is not enough to meet the user load, the fuel cell burns hydrogen to discharge.

[0107] Among them, both the AC / DC step-down transformer and the DC / DC step-down transformer help regulate the power flowing from the power supply into the DC bus and from the DC bus into the storage device. The DC side of the system controls the charging of the electrolyzer to produce hydrogen and the discharge of the fuel cell and supercapacitor. The AC side transmits the power supplemented by the fuel cell and supercapacitor to the grid side while maintaining the DC bus voltage stable, thereby achieving power peak and frequency regulation.

[0108] Example 1: Normal operation mode of a single hydrogen energy storage device

[0109] This embodiment provides an energy management method for a hydrogen-electricity-storage coupling system in a normal operating mode of a single hydrogen energy storage device. If a supercapacitor in the hydrogen-electricity-storage coupling system fails and shuts down, that is, only the hydrogen energy storage device is in a normal operating mode, the specific requirements of the energy management control method in the system island operation mode are as follows:

[0110] ① When the output of the wind turbine generator set is greater than the user's load demand, the excess electricity needs to be consumed by the electrolyzer device and converted into hydrogen and stored in the hydrogen storage tank. Due to its own characteristics, the fuel cell only supports the discharge function, so the fuel cell is in shutdown mode in this mode;

[0111] ② When it is rainy, at night or in windless conditions, the wind turbines are unable to produce power and the wind power load is lower than the user's load demand, the electrolyzer will stop working and the fuel cell will work, releasing electrical energy to make up for the power shortage and achieve system power stabilization.

[0112] Both the electrolyzer and the fuel cell play the role of energy storage, which can bear the low-frequency power fluctuations of the power system and support long-term discharge. However, since the supercapacitors in the system are in shutdown mode, the system cannot bear high-frequency power fluctuations, so the power smoothing effect is not good in the system island operation mode in this mode.

[0113] If the supercapacitor in the hydrogen-electricity-storage coupling system fails and stops, that is, only the hydrogen energy storage device is in normal working mode, the hydrogen-electricity-storage coupling system can be divided into the following operating modes according to the operating mode of the hydrogen energy storage device. The specific energy management process is as follows: Figure 4 As shown:

[0114] Mode S1: The electrolyzer operates normally, and the fuel cell is shut down

[0115] When the system satisfies the following relationship:

[0116] P el-min ≤P W -P L ≤P el-max

[0117] in:

[0118] P el-min ——Minimum residual power of electrolyzer

[0119] P el-max ——The maximum residual power of the electrolyzer

[0120] P W ——Wind power output

[0121] P L ——User load

[0122] The remaining power of the electrolyzer is as follows:

[0123] P el =P W -P L

[0124] in:

[0125] P el ——Residual power of electrolyzer

[0126] The electrolyzer now serves to absorb excess wind power, and the fuel cell is in shutdown mode.

[0127] Mode S2: The electrolyzer operates at rated speed, the fuel cell is shut down, the wind turbine is abandoned, and an additional peak-shaving and frequency-regulating unit is required to increase output

[0128] When the system satisfies the following relationship:

[0129] P W -P L >P el-max

[0130] The electrolyzer is now in rated operation mode, and the specific relationship is as follows:

[0131]

[0132] in:

[0133] P fc Fuel cell power

[0134] The electrolyzer can only absorb part of the wind power at this time, so there is wind abandonment, and the fuel cell is also in shutdown mode.

[0135] Mode S3: The electrolyzer and fuel cell are shut down, the wind turbine is abandoned, and an additional peak-shaving and frequency-regulating unit is required to increase output

[0136] When the system satisfies the following relationship:

[0137] P W -P L <P el-min The electrolyzer is in shutdown mode, the wind turbine generator set is abandoned, and the fuel cell is also in shutdown mode. To maintain the power balance of the system, additional peak-shaving and frequency-regulating units need to be installed. The specific relationship is as follows:

[0138]

[0139] Mode S4: The electrolyzer is shut down and the fuel cell is discharged at rated power

[0140] When the system satisfies the following relationship:

[0141] P L -P W >P fc-max

[0142] P fc-min ≤P L -P W ≤P fc-max

[0143] in:

[0144] P fc-max ——Maximum power of fuel cell

[0145] The electrolyzer is in shutdown mode at this time, and the fuel cell is discharged at rated power to compensate for the power shortage of the system. The specific relationship is as follows:

[0146]

[0147] Mode S5: Electrolyzer shutdown, fuel cell discharge

[0148] When the system satisfies the following relationship:

[0149] P fc-min ≤P L -P W <P fc-max

[0150] in:

[0151] P fc-min ——Minimum fuel cell power

[0152] The electrolyzer is in shutdown mode, and the fuel cell is discharged in normal working mode, which plays a role in compensating the power shortage of the system. The specific relationship is as follows:

[0153]

[0154] Mode 6: The electrolyzer and fuel cell are shut down, the wind turbine is abandoned, and an additional peak-shaving and frequency-regulating unit is required to increase output

[0155] When the system satisfies the following relationship:

[0156] P L -P W <P fc-min

[0157] The electrolyzer and fuel cell are in shutdown mode, the wind turbine generator set is abandoned, and the fuel cell is also in shutdown mode. To maintain the power balance of the system, additional peak-shaving and frequency-regulating units are required. The specific relationship is as follows:

[0158]

[0159] Example 2: Normal operation mode of a single supercapacitor

[0160] If the hydrogen energy storage device in the hydrogen-electricity-storage coupling system fails and stops operating, that is, the electrolyzer, hydrogen storage tank and fuel cell power consumption path stop operating, and only the supercapacitor is in normal working mode, the specific requirements for the energy management control method in the isolated operation mode of the hydrogen-electricity-storage coupling system are as follows:

[0161] When the output of wind turbines is greater than the user load demand, or when it is cloudy, rainy, at night, or without wind, the wind turbines cannot output and the wind power load is lower than the user load demand. In these two cases, the electrolyzer and the fuel cell system cannot respond to electricity. At this time, only the supercapacitor works in the hydrogen-electricity-storage coupling system. However, since the supercapacitor plays a power-type energy storage role and charges and discharges rapidly, it can only respond to high-frequency power fluctuations. Its energy density is small, and it is very easy to have a charging mode over-limit mode, which in turn causes a reduction in life or even a shutdown mode. It cannot respond to long-term power fluctuations. Therefore, the power smoothing effect in the system island operation mode in this mode is not good.

[0162] If the hydrogen energy storage device in the hydrogen-electricity-storage coupling system fails and stops, that is, the electrolyzer, hydrogen storage tank and fuel cell power consumption path stop operating, and only the supercapacitor is in normal working mode, the hydrogen-electricity-storage coupling system can be divided into the following working modes. The specific energy management process is as follows: Figure 5 As shown:

[0163] Mode S1: Charging of supercapacitors in normal operation mode

[0164] When the system satisfies the following relationship:

[0165]

[0166] in:

[0167] P W ——Wind power output

[0168] P L ——User load

[0169] SOC——Supercapacitor Mode of Charge

[0170] SOC m-min ——Supercapacitor minimum charge mode

[0171] SOC m-max ——Supercapacitor maximum charge mode

[0172] The supercapacitor is charged in the normal operation mode, which plays the role of absorbing excess wind power. The specific relationship is as follows:

[0173] P sc =P w -P L

[0174] in:

[0175] P sc ——Supercapacitor power.

[0176] Mode 2: The supercapacitor is shut down, the wind turbine is abandoned, and an external peak-shaving and frequency-regulating unit is required to increase output

[0177] When the system satisfies the following relationship:

[0178] or

[0179] The supercapacitor exceeds the maximum charge mode or the minimum charge mode, so it is in the stop mode. The specific relationship is as follows:

[0180] P sc =0

[0181] Mode 3: The supercapacitor is shut down, the wind turbine is abandoned, and an additional peak-shaving and frequency-regulating unit is required to increase output

[0182] When the system satisfies the following relationship:

[0183] or

[0184] The supercapacitor exceeds the maximum charge mode or the minimum charge mode, so it is in the stop mode. The specific relationship is as follows:

[0185] P sc =0

[0186] Mode 4: Supercapacitor discharge in normal operation mode

[0187] When the system satisfies the following relationship:

[0188]

[0189] The supercapacitor discharges in normal operation mode to make up for the power shortage. The specific relationship is as follows:

[0190] P sc =P L -P w .

[0191] In summary, the present invention uses wind turbines to supply power to the isolated grid system. In order to achieve "peak shaving and valley filling" of electricity, a hydrogen energy storage device is introduced as an energy-type energy storage device to absorb long-term power fluctuations to achieve power peak regulation; a supercapacitor is introduced as a power-type energy storage device to absorb short-term power fluctuations to achieve frequency regulation, giving full play to the complementary advantages of the two. In order to verify the good effect of the hydrogen-electricity-storage coupling system of the present invention in smoothing power fluctuations, the collaborative working mode of the hydrogen energy storage device and the supercapacitor under isolated island operation is innovatively introduced. At the same time, energy management methods corresponding to each working mode are formulated to achieve the collaborative work of each device of the hydrogen-electricity-storage coupling system.

[0192] The above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principle of the present invention, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims

1. A hydrogen-electricity-storage coupling system, characterized in that: It includes a wind turbine generator set, a hydrogen energy storage device, a super capacitor and a user; the wind turbine generator set, the hydrogen energy storage device and the super capacitor form an energy closed loop structure of electric energy-hydrogen energy-electric energy; The hydrogen energy storage device is used to play an energy storage role to smooth long-term power fluctuations and achieve the goal of peak shaving and valley filling in the power grid; The supercapacitor is used to play a role in power-type energy storage to smooth short-term power fluctuations and achieve the goal of power grid frequency regulation; The hydrogen energy storage device includes an electrolyzer, a hydrogen storage tank and a fuel cell. The electrolyzer is connected to the fuel cell through the hydrogen storage tank; the wind turbine generator set and the fuel cell are connected to the power grid and the storage unit through a DC bus, the wind turbine generator set is connected to the DC bus through an AC / DC step-down transformer, the DC bus is connected to the electrolyzer through a DC / DC step-down transformer, the fuel cell is connected to the DC bus through a DC / DC step-down transformer, the supercapacitor as a power-type energy storage device is connected to the DC bus through a DC / DC step-down transformer, and the DC bus is connected to the user through a DC / AC step-down transformer.

2. The energy management method of a hydrogen-electricity-storage coupling system according to claim 1, characterized in that: The following operating modes are included: Mode S1: The electrolyzer operates normally, the fuel cell and supercapacitor are shut down, the wind turbine generator set abandons wind, and an external peak-shaving and frequency-regulating unit is required to increase output; Mode S2: The electrolyzer operates at rated speed, the fuel cell is shut down, and the supercapacitor is charged; Mode S3: The electrolyzer operates at rated capacity, the fuel cell and supercapacitor are shut down, the wind turbine generator set abandons wind, and an external peak-shaving and frequency-regulating unit is required to increase output; Mode S4: The electrolyzer operates at minimum output, the fuel cell is shut down, and the supercapacitor is discharged; Mode S5: electrolyzer, fuel cell and supercapacitor are all shut down; Mode S6: The electrolyzer is shut down, the fuel cell operates normally, and the supercapacitor is shut down; Mode S7: The electrolyzer is shut down, the fuel cell is discharged at rated operation, and the supercapacitor is discharged; Mode S8: electrolyzer shut down, fuel cell rated operation, supercapacitor shut down; Mode S9: electrolyzer and fuel cell shut down, supercapacitor discharge; Mode S10: The electrolyzer, fuel cell and supercapacitor are all shut down.

3. The energy management method of a hydrogen-electricity-storage coupling system according to claim 2, characterized in that: In the mode S1, the system needs to satisfy the following relationship: P el-min ≤P W -P L ≤P el-max in: P el-min ——Minimum residual power of electrolyzer P el-max ——The maximum residual power of the electrolyzer P W ——Wind power output P L ——User load The remaining power of the electrolyzer is as follows: P el =P W -P L in: P el ——Residual power of electrolyzer The electrolyzer now acts as a buffer for excess wind power, while the fuel cell and supercapacitor are in shutdown mode; In the mode S2, the system needs to satisfy the following relationship: in: SOC——Supercapacitor Mode of Charge SOC m-min ——Supercapacitor minimum charge mode SOC m-max ——Supercapacitor maximum charge mode The electrolyzer is in rated operation mode at this time, the excess wind power is used to charge the supercapacitor, and the fuel cell is in stop mode. The specific relationship is as follows: in: P sc-ref ——Excess wind power supplies supercapacitor charging power P fc ——Fuel cell power.

4. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In the mode S3, the system needs to satisfy the following relationship: or The electrolyzer is in rated operation mode, and the supercapacitor and fuel cell are in shutdown mode. If the wind turbine generator set abandons wind, additional peak-shaving and frequency-regulating units need to be installed to maintain the power balance of the system. The specific relationship is as follows: in: P sc ——Supercapacitor power.

5. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In the mode S4, the system needs to satisfy the following relationship: The electrolyzer is running in the minimum output mode at this time, and the supercapacitor plays the role of compensating the power shortage of the system. During the discharge of the supercapacitor, the SOC mode continues to decrease until it drops to SOC min , the fuel cell is still in shutdown mode, the specific relationship is as follows:

6. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In the mode S5, the system needs to satisfy the following relationship: or The electrolyzer, fuel cell and supercapacitor are all shut down and running, and the specific relationship is as follows: In the mode S6, the system needs to satisfy the following relationship: P fc-min ≤P L -P W ≤P fc-max in: P fc-max ——Maximum power of fuel cell P fc-min ——Minimum fuel cell power The electrolyzer is in shutdown mode, the fuel cell acts to compensate for the power difference of the system, and the supercapacitor is in shutdown mode. The specific relationship is as follows:

7. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In the mode S7, the system needs to satisfy the following relationship: The electrolyzer is in shutdown mode, the fuel cell is in rated mode, and the supercapacitor is discharged to make up for the power shortage of the system. The specific relationship is as follows: In the mode S8, the system needs to satisfy the following relationship: or The electrolyzer is in shutdown mode, the fuel cell is in rated mode, and the supercapacitor is in shutdown mode. The system needs to increase output to maintain power balance. The specific relationship is as follows:

8. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In the mode S9, the system needs to satisfy the following relationship: The electrolyzer is in shutdown mode, and the supercapacitor discharges to compensate for the power shortage of the system. During the discharge of the supercapacitor, the SOC continues to decrease until it drops to SOC m-min , the fuel cell is in shutdown mode, the specific relationship is as follows:

9. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In the mode S10, the system needs to satisfy the following relationship: or The electrolyzer, fuel cell and supercapacitor are in shutdown mode, and the relationship is as follows:

10. The energy management method of a hydrogen-electricity-storage coupling system according to claim 3, characterized in that: In mode S2, the supercapacitor charge mode SOC has a value range of 0.1-0.9, and the specific calculation formula is as follows: in: |P s |——The absolute value of the system net load, which is the absolute value of the difference between wind power output power and user load P sc-min ——Supercapacitor SC minimum power P sc-max ——Maximum power of supercapacitor SC.

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