Power system, direct current coupling device and control method of direct current coupling device

Abstract

The invention relates to an electric power system, a direct current coupling device and a control method thereof, the electric power system determines an operation mode according to the state and parameters of one or more of a power supply, an energy storage device and a hydrogen production device, selects an electric power source for hydrogen production and a corresponding electric power transmission path, and provides electric energy by using the selected electric power source; and electric energy conversion and transmission are carried out through the selected power transmission path so as to provide electric energy required by the hydrogen production device. The selected optimal power source and power transmission path can supply power to the hydrogen production device in a stable, continuous, high-efficiency and low-cost manner.

Description

Technical Field

[0001] This case relates to the field of hydrogen production technology, specifically a new energy power system, a DC coupling device, and its control method. Background Technology

[0002] Hydrogen energy can absorb large-scale and efficient renewable energy sources, redistribute energy across different industries and regions, act as an energy buffer to improve the resilience of the energy system, and reduce carbon emissions from transportation, industrial energy use, and building heating. The initial goal of the hydrogen energy industry is to develop with zero or low carbon emissions; therefore, hydrogen production using renewable energy will gradually replace current coal-based and natural gas-based hydrogen production methods.

[0003] Currently, mainstream water electrolysis hydrogen production equipment has a slow dynamic response and is difficult to start up or change loads quickly, thus requiring a relatively stable power supply for hydrogen production. However, renewable energy power generation is intermittent and fluctuates, making it poorly matched with hydrogen production needs.

[0004] Therefore, it is necessary to develop a new energy power system, DC coupling device and control method to power hydrogen production equipment in order to solve the problems faced by previous technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a power system, a DC coupling device, and a control method thereof, wherein the power system determines an operating mode based on the state and parameters of one or more of a power source, an energy storage device, and a hydrogen production device, selects a power source for hydrogen production and a corresponding power transmission path, uses the selected power source to provide electrical energy, and performs power conversion and transmission through the selected power transmission path to provide the electrical energy required by the hydrogen production device. The selected optimal power source and power transmission path can supply power to the hydrogen production device in a stable, continuous, efficient, and low-cost manner.

[0006] To achieve the above objectives, one embodiment of this invention provides an electrical system for supplying power to a hydrogen production device. The electrical system includes multiple power sources, an energy storage device, and a hydrogen production power supply device. The hydrogen production power supply device has an AC terminal, a DC output terminal, a DC coupling terminal, and a controller. The AC terminal is electrically connected to the multiple power sources via an AC bus. The DC output terminal is electrically connected to the hydrogen production device, and the DC coupling terminal is electrically connected to the energy storage device. The controller determines the operating mode based on the status and parameters of the multiple power sources, the energy storage device, and / or the hydrogen production device. It selectively receives and converts electrical energy provided by at least one of the multiple power sources and / or the energy storage device to supply power to the hydrogen production device using a power transmission path. The hydrogen production power supply device and / or the energy storage device provide the power transmission path.

[0007] To achieve the above objectives, another embodiment of this application provides a DC coupling device comprising an energy storage device and a power supply device. The power supply device has an AC terminal, a DC output terminal, a DC coupling terminal, and a controller. The AC terminal is electrically connected to at least one power source via an AC bus, the DC output terminal is electrically connected to an electrical load, and the DC coupling terminal is electrically connected to the energy storage device. The controller determines the operating mode based on the state and parameters of the at least one power source, the energy storage device, and / or the electrical load, selectively receiving and converting the power provided by the at least one power source and / or the energy storage device to supply power to the electrical load using a power transmission path. The power supply device and / or the energy storage device provide the power transmission path.

[0008] To achieve the above objectives, another embodiment of this application provides a control method applied to a power system for supplying power to a hydrogen production device. The control method includes the following steps: First, multiple power sources, energy storage devices, and a hydrogen production power supply device are configured. The hydrogen production power supply device has an AC terminal, a DC output terminal, and a DC coupling terminal. The AC terminal is electrically connected to the multiple power sources via an AC bus, the DC output terminal is electrically connected to the hydrogen production device, and the DC coupling terminal is electrically connected to the energy storage device. Next, an operating mode is determined based on the status and parameters of the multiple power sources, energy storage devices, and / or the hydrogen production device. Power is selectively received and converted from at least one of the multiple power sources and / or the energy storage device to supply power to the hydrogen production device using a power transmission path. The hydrogen production power supply device and / or the energy storage device provide the power transmission path. Attached Figure Description

[0009] Figure 1 This is the circuit topology diagram of the power system in this case;

[0010] Figure 2 for Figure 1 A detailed circuit topology diagram of a first embodiment of the power system is shown.

[0011] Figure 3A for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the first power supply mode under off-grid conditions.

[0012] Figure 3B for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the second power supply mode under off-grid conditions.

[0013] Figure 3C for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the third power supply mode under off-grid conditions.

[0014] Figure 3D for Figure 2The diagram shows the power transmission path and control block diagram of the power system in the fourth power supply mode under off-grid conditions.

[0015] Figure 3E for Figure 2 The diagram shows the power transmission path and control block diagram of the power system under the first power supply mode in grid-connected conditions.

[0016] Figure 3F for Figure 2 The diagram shows the power transmission path and control block diagram of the power system under the second power supply mode in grid-connected conditions.

[0017] Figure 3G for Figure 2 The diagram shows the power transmission path and control block diagram of the power system under the third power supply mode in grid-connected conditions.

[0018] Figure 3H for Figure 2 The diagram shows the power transmission path and control block diagram of the power system under the fourth power supply mode in grid-connected conditions.

[0019] Figure 4 for Figure 1 A detailed circuit topology diagram of a second embodiment of the power system is shown.

[0020] Figure 5 for Figure 1 A detailed circuit topology diagram of a third embodiment of the power system is shown.

[0021] Figure 6 for Figure 1 The diagram shows a detailed circuit topology of the fourth embodiment of the power system.

[0022] Figure 7 for Figure 1 The diagram shows a detailed circuit topology of the fifth embodiment of the power system.

[0023] Figure 8 for Figure 1 A detailed circuit topology diagram of the sixth embodiment of the power system shown;

[0024] Figure 9 for Figure 1 The diagram shows a detailed circuit topology of the seventh embodiment of the power system.

[0025] Figure 10A and Figure 10B The flowchart of the power system control method in this case; and

[0026] Figure 11 The graph shows the relationship between the power of the converter used in the power system of this case and the frequency of the AC bus.

[0027] The reference numerals in the attached figures are explained as follows:

[0028] 1, 1a, 1b, 1c, 1d, 1e, 1f: Power system

[0029] 20: AC busbar

[0030] 21: Power Grid

[0031] 2a: First power generation unit

[0032] 2b: Second power generation unit

[0033] 22: Wind Turbine

[0034] 23: Photovoltaic inverter

[0035] 24: Wind turbine

[0036] 25: Photovoltaic panels

[0037] 3, 3a, 3b, 3c, 3d: Hydrogen production and power supply unit

[0038] 31: Communication Terminal

[0039] 32: DC output terminal

[0040] 33: DC coupling terminal

[0041] 34: AC / DC converter

[0042] 35: DC / DC converter

[0043] 37: Controller

[0044] 371: Mode Selection Unit

[0045] 372: AC / DC control unit

[0046] 373: DC / DC Control Unit

[0047] 374: Energy Storage Control Unit

[0048] 4: Hydrogen production unit

[0049] 5: Energy storage devices

[0050] 51: Energy Storage Converter

[0051] 52: Energy storage components

[0052] 53: Second energy storage converter

[0053] 54: Second photovoltaic panel

[0054] P windOutput power signal

[0055] P pv Output power signal

[0056] P EC Hydrogen production power command

[0057] V bus_ref DC bus voltage command

[0058] I o_ref Current command

[0059] P o_ref Power command

[0060] V abc AC voltage

[0061] I abc Alternating current

[0062] V bus Bus voltage

[0063] V o Output voltage

[0064] I o Output current

[0065] I b :Voltage

[0066] V b Current

[0067] S1-S16: Steps Detailed Implementation

[0068] Some typical embodiments that embody the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention can have various variations in different forms, all of which do not depart from the scope of this invention, and the descriptions and drawings therein are essentially for illustrative purposes and not for limiting this invention.

[0069] Please see Figure 1This is a circuit topology diagram of the power system of the first embodiment of this case. The power system 1 of this case can be used to supply power to the hydrogen production device 4. As shown in the figure, the power system 1 of this case includes multiple power sources 21, 2a, 2b, a hydrogen production power supply device 3, and an energy storage device 5. The multiple power sources can be the power grid, green energy power generation devices, and the power generation devices can be, but are not limited to, wind power generation devices, photovoltaic power generation devices, fuel power generation devices, etc. The hydrogen production power supply device 3 is electrically connected to the multiple power sources 21, 2a, 2b through an AC bus 20. The hydrogen production power supply device 3 has an AC terminal 31, a DC output terminal 32, and a DC coupling terminal 33. The AC terminal 31 is electrically connected to the AC bus 20, and the DC output terminal 32 is electrically connected to the hydrogen production device 4. The energy storage device 5 is electrically connected to the DC coupling terminal 33 of the hydrogen production power supply device 3, and forms a DC coupling device with the hydrogen production power supply device 3. The hydrogen production power supply device 3 selectively receives power from at least one power source and / or the energy storage device 5, and converts the power into DC power to supply power to the hydrogen production device 4. Furthermore, the hydrogen production power supply unit 3 may also include a controller electrically connected to multiple power sources 21, 2a, 2b, energy storage device 5, and hydrogen production unit 4. Based on the status and parameters of one or more of these devices, the controller determines the operating mode and selects the power source and corresponding power transmission path for hydrogen production. Multiple power transmission paths exist between the multiple power sources 21, 2a, 2b, and hydrogen production unit 4. Each power transmission path includes at least one power converter, which is used to perform power conversion and transmission within the corresponding power transmission path. For example, based on the status and parameters of the multiple devices, the optimal power source is selected. A switch, relay, or power converter in the power transmission path is used to select the power transmission path. The selected power source provides electrical energy, and the selected power transmission path converts and transmits the power to provide the power required by the hydrogen production unit 4. The selected optimal power source and power transmission path supply power to the hydrogen production unit 4 in a stable, continuous, efficient, and low-cost manner.

[0070] The controller includes a mode selection unit and multiple power control units. The mode selection unit is electrically connected to multiple power sources and the hydrogen production unit, and is configured to: receive multiple first parameters, determine the power source for supplying the hydrogen production unit based on the first parameters, and generate multiple power commands. Each power control unit is electrically connected to the mode selection unit, a corresponding power transmission path, and a corresponding power converter, and is configured to: receive multiple second parameters and at least one power command output by the mode selection unit, and control the corresponding power converter to operate based on the second parameters and the received power command, so that the corresponding power transmission path provides power to the hydrogen production unit.

[0071] Furthermore, the selected optimal power source includes at least one power generation device and / or one energy storage device, the control method of which will be further explained below.

[0072] Please see Figure 2, it is Figure 1 The diagram shows a detailed circuit topology of a first embodiment of the power system. As shown, the power system 1 includes a power grid 21, a first power generation device 2a, a second power generation device 2b, an energy storage device 5, and a hydrogen production and power supply device 3. The hydrogen production and power supply device 3 is electrically connected to the power grid 21, the first power generation device 2a, and the second power generation device 2b via an AC bus 20. The first power generation device 2a is, for example but not limited to, a wind power generation device, and includes a wind turbine 24 and a wind turbine converter 22. The second power generation device 2b is, for example but not limited to, a photovoltaic power generation device, and includes a photovoltaic panel 25 and a photovoltaic inverter 23.

[0073] The hydrogen production power supply device 3 includes an AC / DC converter 34 and a DC / DC converter 35. The AC / DC converter 34 may be, but is not limited to, a PWM rectifier. The AC terminal of the AC / DC converter 34 forms the AC terminal 31 of the hydrogen production power supply device 3 or is electrically connected to the AC terminal 31 of the hydrogen production power supply device 3. The DC terminal of the AC / DC converter 34 forms the DC coupling terminal 33 of the hydrogen production power supply device 3 or is electrically connected to the DC coupling terminal 33 of the hydrogen production power supply device 3. The input terminal of the DC / DC converter 35 is electrically connected to the DC coupling terminal 33 of the hydrogen production power supply device 3, and the output terminal of the DC / DC converter 35 forms the DC output terminal 32 of the hydrogen production power supply device 3 or is electrically connected to the DC output terminal of the hydrogen production power supply device 3. The energy storage device 5 includes an energy storage converter 51 and an energy storage element 52. The energy storage converter 51 can be a full-power DC / DC converter or a partial-power DC / DC converter, such as a compensated DC / DC converter, to reduce the cost of the DC / DC converter. The first terminal 511 of the energy storage converter 51 is electrically connected to the DC coupling terminal 33 of the hydrogen production power supply device 3, and the second terminal 512 of the energy storage converter 51 is electrically connected to the energy storage element 52. The AC / DC converter 34, the DC / DC converter 35, and the energy storage converter 51 are coupled to the DC coupling terminal 33 to form a DC bus. The AC / DC converter 34 and / or the energy storage converter 51 provide and stabilize the DC bus voltage, and the DC / DC converter 35 converts the DC bus voltage into an output voltage to power the hydrogen production device 4. The hydrogen production device 4 is, for example, an electrolyzer. The voltage required for an alkaline electrolyzer is typically between 300V and 700V, while the voltage required for a PEM can reach up to 1500V.

[0074] In one specific implementation, the AC / DC converter 34, DC / DC converter 35, and energy storage converter 51 of the energy storage device 5 are located inside the same housing (not shown), while the energy storage element 52 of the energy storage device 5 is additionally disposed outside the housing. Thus, the AC / DC converter 34, DC / DC converter 35, and energy storage converter 51 form a three-port power device. The AC terminal of the AC / DC converter 34 (i.e., the AC terminal 31 of the hydrogen production power supply device 3) constitutes the first power terminal of the three-port power device, the output terminal of the DC / DC converter 35 (i.e., the DC output terminal 32 of the hydrogen production power supply device 3) constitutes the second power terminal of the three-port power device, and the second terminal 512 of the energy storage converter 51 constitutes the third power terminal of the three-port power device. In another specific implementation, the AC / DC converter 34, DC / DC converter 35, energy storage converter 51, and energy storage element 52 are located inside the same housing. Thus, the AC / DC converter 34, DC / DC converter 35, energy storage converter 51, and energy storage element 52 form a two-port power device. The AC terminal of the AC / DC converter 34 (i.e., the AC terminal 31 of the hydrogen production power supply device 3) constitutes the first power terminal of the two-port power device, and the output terminal of the DC / DC converter 35 (i.e., the DC output terminal 32 of the hydrogen production power supply device 3) constitutes the second power terminal of the two-port power device. In yet another specific implementation, the AC / DC converter 34 and DC / DC converter 35 share one housing, and the energy storage converter 51 and energy storage element 52 of the energy storage device 5 share another housing. Thus, the power conversion device formed by the AC / DC converter 34 and DC / DC converter 35 is a three-port power device. The AC terminal of the AC / DC converter 34 (i.e., the AC terminal 31 of the hydrogen production power supply device 3) constitutes the first power terminal of the three-port power device, the output terminal of the DC / DC converter 35 (i.e., the DC output terminal 32 of the hydrogen production power supply device 3) constitutes the second power terminal of the three-port power device, and the DC terminal of the AC / DC converter 34 constitutes the third power terminal of the three-port power device. The energy storage converter 51 and energy storage element 52 of the energy storage device 5 are mechanically attached to the third power terminal of the hydrogen production power supply device 3, i.e., the DC coupling terminal 33. In another specific implementation, the AC / DC converter 34, the DC / DC converter 35, and the energy storage converter 51 are all independent power modules, and the three independent power modules are mechanically connected at the DC coupling terminal 33. In one embodiment, the DC coupling terminal 33 can also be located within the DC / DC converter 35 or within the energy storage converter 51. The hydrogen production power supply device 3 and the energy storage device 5 of this invention can adopt integrated power modules for unified energy management and communication, or can adopt discrete power modules for easy maintenance.

[0075] Please continue to refer to this. Figure 2Multiple power transmission paths exist between the power grid 21, the first power generation device 2a, the second power generation device 2b, the energy storage device 5, and the hydrogen production and power supply device 3. Each power transmission path includes one or more power converters, switches, or relays. The hydrogen production and power supply device 3 will select a superior power source and power transmission path to supply power to the hydrogen production device 4 based on the status and parameters of one or more of the power grid 21, the first power generation device 2a, the second power generation device 2b, the hydrogen production device 4, and the energy storage device 5. Correspondingly, the hydrogen production and power supply device 3 further includes a controller 37, which is electrically connected to the power grid 21, the first power generation device 2a, the second power generation device 2b, the AC / DC converter 34, the DC / DC converter 35, the hydrogen production device 4, the energy storage converter 51, and the energy storage element 52. The controller 37 determines the operating mode and power source based on one or more first parameters and outputs multiple power commands. Based on the multiple power commands and multiple second parameters, it outputs multiple control signals, which control multiple power converters to select at least one power transmission path. One or more first parameters are parameters provided by multiple power sources or multiple power loads, such as one or more parameters from the power grid 21, the first power generation device 2a, the second power generation device 2b, the hydrogen production device 4, and / or the energy storage device 5. Multiple second parameters are parameters present in the power transmission path, such as AC bus voltage, output voltage, output current, etc. In this embodiment, the DC / DC converter 35 and the energy storage converter 51 of the hydrogen production power supply device 3 can independently control the hydrogen production device 4 and the energy storage device 5, thus improving control flexibility and compatibility with various application scenarios.

[0076] In this embodiment, the controller 37 includes a mode selection unit 371, an AC / DC control unit 372, a DC / DC control unit 373, and an energy storage control unit 374. The mode selection unit 371 is electrically connected to the first power generation device 2a, the second power generation device 2b, and the hydrogen production device 4, and is used to receive the output power signal P of the first power generation device 2a. wind The output power signal P of the second power generation device 2b pv The mode selection unit 371 also receives status signals from the hydrogen production unit 4 (e.g., port voltage, current, cycle, temperature, pressure, etc.). The mode selection unit 371 also receives grid signals from the grid 21 and hydrogen production power commands P. EC Among them, the grid signal and the hydrogen production power command P EC The grid signal can be generated by the controller 37 itself or from the upper-level controller, and can indicate the grid-connected or off-grid status of the grid 21. As explained above, the output power signal P of the first power generation device 2a... wind The output power signal P of the second power generation device 2b pv Status signals of hydrogen production unit 4, power grid signals, and hydrogen production power command P ECAll of these can be considered as first parameters. The mode selection unit 371 outputs multiple power commands based on one or more of the received first parameters, wherein the power commands may be, for example, the DC bus voltage command V. bus_ref Current command I o_ref or power command P o_ref Therefore, the controller 37 can utilize multiple power commands to complete energy scheduling of multiple power sources and determine the control modes of multiple power converters in the power transmission path, as will be explained below. The AC / DC control unit 372 is electrically connected to the mode selection unit 371 and the AC terminal (i.e., AC terminal 31 of the hydrogen production power supply device 3) and DC terminal (i.e., DC coupling terminal 33 of the hydrogen production power supply device 3) of the AC / DC converter 34, and receives at least one power command, such as the DC bus voltage command V. bus_ref The AC / DC control unit 372 also receives the AC voltage V from the AC terminal 31. abc Alternating current I abc DC bus voltage V at DC coupling terminal 33 bus The AC / DC control unit 372 outputs a first control signal to control the operation of the AC / DC converter 34, where the first control signal may be, for example, a first PWM signal. Therefore, the AC / DC control unit 372 operates according to the DC bus voltage command V provided by the mode selection unit 371. bus_ref Based on the relevant parameters of the AC / DC converter 34, the first PWM signal is output to control the AC / DC converter 34 to stabilize the DC bus voltage V. bus The DC / DC control unit 373 is electrically connected to the output terminal of the mode selection unit 371 and the DC / DC converter 35 (i.e., the DC output terminal 32 of the hydrogen production power supply device 3), and receives at least one power command, such as an output current command I. o_ref The DC / DC control unit 373 also receives the output voltage V from the DC output terminal 32. o and output current I o The DC / DC control unit 373 outputs a second control signal to control the operation of the DC / DC converter 35, wherein the second control signal may be, for example, a second PWM signal. Therefore, the DC / DC control unit 373, according to the output current command I provided by the mode selection unit 371, performs the operation. o_ref Based on the relevant parameters of the DC / DC converter 35, a second PWM signal is output to control the DC / DC converter 35, thereby controlling the output current I. o The energy storage control unit 374 is electrically connected to the second terminal 512 of the energy storage element 52 and the energy storage converter 51, and receives the voltage I from the energy storage element 52. b Current V b DC bus voltage V at DC coupling terminal 33 busThe energy storage control unit 374 outputs a third control signal to control the operation of the energy storage converter 51, which may be, for example, a third PWM signal. Therefore, the energy storage control unit 374 outputs a third PWM signal to control the charging and discharging current of the energy storage converter 51 based on the relevant parameters of the energy storage element 52 and the energy storage converter 51.

[0077] In another embodiment, the energy storage control unit 374 is electrically connected to the mode selection unit 371, the energy storage element 52, and the second terminal 512 of the energy storage converter 51, and receives at least one power command, such as a DC bus voltage command V. bus_ref The voltage I of energy storage element 52 b Current V b and bus voltage V bus The energy storage control unit 374 outputs a third control signal to control the operation of the energy storage converter 51, which may be, for example, a third PWM signal. The energy storage control unit 374 operates according to the DC bus voltage command V. bus_ref The third PWM signal is output based on the relevant parameters of the energy storage element 52 and the energy storage converter 51 to control the charging and discharging voltage of the energy storage converter 51, thereby stabilizing the DC bus voltage V. bus At this time, the AC / DC converter 34 does not need to stabilize the bus voltage V of the DC coupling terminal 33. bus .

[0078] The control methods of controller 37 and the selected power transmission paths will be explained below according to different modes. Please refer to [link / reference]. Figure 3A and cooperate Figure 2 ,in Figure 3A for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the first power supply mode under off-grid conditions. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal, confirming that the grid 21 is not connected to the AC bus 20 (i.e., in the off-grid condition). Next, the mode selection unit 371 selects the total output power (P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Equal to hydrogen production power command P EC The first power generation unit 2a and the second power generation unit 2b can be selected to simultaneously supply power to the hydrogen production unit 4. The AC / DC control unit 372 operates according to the DC bus voltage command V provided by the mode selection unit 371. bus_ref The AC voltage V at the AC terminal of the AC / DC converter 34 obtained by sampling. abc Alternating current I abc and bus voltage V busThe first control signal is output to control the AC / DC converter 34 to perform high-frequency switching, so that the AC / DC converter 34 receives AC power from the first power generation device 2a and the second power generation device 2b, and converts it into DC power to provide DC power to the DC / DC converter 35. At the same time, the bus voltage V at the DC coupling terminal 33 between the AC / DC converter 34 and the DC / DC converter 35 is stabilized. bus The DC / DC control unit 373 outputs current command I according to the mode selection unit 371. o_ref and the output voltage V of the sampled DC / DC converter 35 o and output current I o A second control signal is output to control the DC / DC converter 35 to perform high-frequency switching, so that the DC / DC converter 35 receives DC power from the AC / DC converter 34 and converts it into DC output power to supply the hydrogen production unit 4. When in off-grid mode, with good wind and sunlight conditions, and the total output power P of the first power generation unit 2a and the second power generation unit 2b is... green Equal to hydrogen production power command P EC At this time, the controller 37 selects the first power generation device 2a and the second power generation device 2b to supply power to the hydrogen production device 4, and selects the power transmission path formed by the AC / DC converter 34 and the DC / DC converter 35 to provide the power from the first power generation device 2a and the second power generation device 2b to the hydrogen production device 4, thus achieving green hydrogen production. At this time, the energy storage device 5 does not participate in power conversion and transmission; for the sake of simplicity, it is omitted. Figure 3A The energy storage control unit 374 is omitted. (By...) Figure 3A It can be seen that in the first power supply mode under off-grid conditions, all the electrical energy generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b) is used to supply hydrogen production device 4 to produce hydrogen, so as to provide the power required by hydrogen production device 4.

[0079] Please see Figure 3B and cooperate Figure 2 ,in Figure 3B for Figure 1 The diagram shows the power transmission path and control block diagram of the power system in the second power supply mode under off-grid conditions. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal, confirming that the grid 21 is not connected to the AC bus 20 (i.e., in the off-grid condition). Next, the mode selection unit 371 selects the total output power (P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Less than the hydrogen production power command P EC And further confirm the total output power Pgreen When the voltage is 0, the energy storage device 5 supplies power to the hydrogen production device 4 only. The energy storage control unit 374 operates according to the DC bus voltage command V provided by the mode selection unit 371. bus_ref The bus voltage V at the DC terminal of the AC / DC converter 34 obtained by sampling. bus and the voltage I of energy storage element 52 b Current V b The first control signal is output to control the energy storage converter 51 to perform high-frequency switching, so that the energy storage converter 51 receives the DC power provided by the energy storage element 52, and provides it to the DC / DC converter 35 after conversion, while stabilizing the bus voltage V of the DC coupling terminal 33. bus The DC / DC control unit 373 outputs current command I according to the mode selection unit 371. o_ref and the output voltage V of the sampled DC / DC converter 35 o and output current I o The controller outputs a second control signal to control the DC / DC converter 35 to perform high-frequency switching, enabling the DC / DC converter 35 to receive DC power from the energy storage converter 51 and convert it into DC output power to supply the hydrogen production device 4. When the power supplied by the first power generation device 2a and the second power generation device 2b is insufficient, the controller 37 selects the energy storage device 5 to supply power to the hydrogen production device 4, and selects the power transmission path formed by the energy storage converter 51 and the DC / DC converter 35 to supply the power of the energy storage element 52 to the hydrogen production device 4, thus realizing hydrogen production. At this time, the AC / DC converter 34 does not participate in power conversion and transmission; it is omitted for simplicity. Figure 3B The AC / DC control unit 372 is omitted. Figure 3B It can be seen that in the second power supply mode under off-grid conditions, all the electrical energy generated by the energy storage device 5 is used to supply the hydrogen production device 4 to produce hydrogen, so as to provide the power required by the hydrogen production device 4.

[0080] Please see Figure 3C and cooperate Figure 2 ,in Figure 3C for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the third power supply mode under off-grid conditions. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal, confirming that the grid 21 is not connected to the AC bus 20 (i.e., in the off-grid condition). Next, the mode selection unit 371 selects the total output power (i.e., P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Greater than the hydrogen production power command PEC The first power generation unit 2a and the second power generation unit 2b can be selected to simultaneously supply power to the hydrogen production unit 4 and the energy storage unit 5. The AC / DC control unit 372, based on the power command P provided by the mode selection unit 371, [continues to operate]. ref The AC voltage V at the AC terminal of the AC / DC converter 34 obtained by sampling. abc Alternating current I abc and bus voltage V bus The first control signal is output to control the AC / DC converter 34 to perform high-frequency switching, so that the AC / DC converter 34 receives AC power from the first power generation device 2a and the second power generation device 2b, and converts it into DC power to provide DC / DC converter 35 and energy storage converter 51, while stabilizing the AC side power of the AC / DC converter 34. The DC / DC control unit 373 outputs the output current command I provided by the mode selection unit 371. o_ref and the output voltage V of the sampled DC / DC converter 35 o and output current I o The second control signal is output to control the DC / DC converter 35 to perform high-frequency switching, so that the DC / DC converter 35 receives DC power from the AC / DC converter 34 and converts it into DC output power to supply the hydrogen production unit 4. The energy storage control unit 374 controls the DC bus voltage command V provided by the mode selection unit 371. bus_ref The bus voltage V at the DC terminal of the AC / DC converter 34 obtained by sampling. bus and the voltage I of energy storage element 52 b Current V b The third control signal is output to control the energy storage converter 51 to perform high-frequency switching, so that the energy storage converter 51 receives DC power provided by the AC / DC converter 34, converts it and provides it to the energy storage element 52, and at the same time stabilizes the bus voltage V of the DC coupling terminal 33. bus When the generator is off-grid and wind and sunlight conditions are favorable, and the total output power P of the first generator 2a and the second generator 2b is... green Greater than the hydrogen production power command P EC At the same time, the controller 37 selects the first power generation device 2a and the second power generation device 2b to simultaneously supply power to the hydrogen production device 4 and the energy storage device 5. It also selects a first power transmission path formed by the AC / DC converter 34 and the DC / DC converter 35 to supply power from the first power generation device 2a and the second power generation device 2b to the hydrogen production device 4, and simultaneously selects a second power transmission path formed by the AC / DC converter 34 and the energy storage converter 51 to supply power from the first power generation device 2a and the second power generation device 2b to the energy storage device 5, thereby achieving green hydrogen production and charging the energy storage element 52. Figure 3CIt can be seen that in the third power supply mode under off-grid conditions, the electrical energy generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b) is used to supply hydrogen production device 4 for hydrogen production and to supply energy storage element 52 for charging.

[0081] In another embodiment, if the energy storage device 5 is not allowed to be charged, the power system 1 can also limit the output power of the first power generation device 2a and the second power generation device 2b in the third power supply mode under off-grid conditions to match the power demand of the hydrogen production device 4.

[0082] Please see Figure 3D and cooperate Figure 2 ,in Figure 3D for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the fourth power supply mode under off-grid conditions. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal, confirming that the grid 21 is not connected to the AC bus 20 (i.e., in the off-grid condition). Next, the mode selection unit 371 selects the total output power (i.e., P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Less than the hydrogen production power command P EC And further confirm the total output power P green When the value is greater than 0, the first power generation device 2a, the second power generation device 2b, and the energy storage device 5 are selected to supply power to the hydrogen production device 4. The AC / DC control unit 372, based on the power command P provided by the mode selection unit 371, [continues to operate]. ref The AC voltage V at the AC terminal of the AC / DC converter 34 obtained by sampling. abc and alternating current I abc The first control signal is output to control the AC / DC converter 34 to perform high-frequency switching, so that the AC / DC converter 34 receives AC power from the first power generation device 2a and the second power generation device 2b, and converts it into DC power to supply DC / DC converter 35. Simultaneously, the AC-side power of the AC / DC converter 34 is controlled. The energy storage control unit 374 controls the DC bus voltage command V provided by the mode selection unit 371. bus_ref The bus voltage V at the DC terminal of the AC / DC converter 34 obtained by sampling. bus and the voltage I of energy storage element 52 b Current V bThe third control signal is output to control the energy storage converter 51 to perform high-frequency switching, so that the energy storage converter 51 receives the DC power provided by the energy storage element 52, and provides it to the DC / DC converter 35 after conversion, while stabilizing the bus voltage V of the DC coupling terminal 33. bus The DC / DC control unit 373 outputs current command I according to the mode selection unit 371. o_ref and the output voltage V of the sampled DC / DC converter 35 o and output current I o A second control signal is output to control the DC / DC converter 35 to perform high-frequency switching, enabling the DC / DC converter 35 to receive DC power from the AC / DC converter 34 and the energy storage converter 51, and convert it into DC output power to supply the hydrogen production unit 4. When the unit is off-grid, or when wind and sunlight conditions are weak and cannot fully meet the hydrogen production demand, the total power P output by the first power generation unit 2a and the second power generation unit 2b is [not specified]. green Less than the hydrogen production power command P EC And further confirm the total output power P green When the value is greater than 0, the controller 37 selects the first power generation device 2a, the second power generation device 2b, and the energy storage device 5 to simultaneously supply power to the hydrogen production device 4. It also selects the first power transmission path formed by the AC / DC converter 34 and the DC / DC converter 35 to supply power from the first power generation device 2a and the second power generation device 2b to the hydrogen production device 4, and simultaneously selects the second power transmission path formed by the energy storage device 5 and the DC / DC converter 35 to supply power from the energy storage device 5 to the hydrogen production device 4. Figure 3D It can be seen that in the fourth power supply mode under off-grid conditions, the electricity generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b) and the energy storage device 5 is used together to supply the hydrogen production device 4 to produce hydrogen, so as to meet the power requirements of the hydrogen production device 4.

[0083] Please see Figure 3E and cooperate Figure 2 ,in Figure 3E for Figure 2 The diagram shows the power transmission path and control block diagram of the power system under the first power supply mode in grid-connected conditions. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal, confirming that the grid 21 is connected to the AC bus 20 (i.e., under grid-connected conditions). Next, the mode selection unit 371 selects the total output power (P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Greater than the hydrogen production power command P ECWhen it is confirmed that the energy storage device 5 is not allowed to be charged, the first power generation device 2a and the second power generation device 2b are selected to simultaneously supply power to the hydrogen production device 4 and the power grid 21. At this time, the AC terminal power of the AC / DC converter 34 is the total output power of the first power generation device 2a and the second power generation device 2b (i.e., P). green =P pv +P wind Subtracting the power supplied to grid 21, the power transmission path and control method for powering hydrogen production unit 4 are similar to... Figure 3A The power transmission path and control method shown will not be described in detail here. Under grid-connected conditions and with favorable wind and sunlight conditions, the total power output P of the first power generation unit 2a and the second power generation unit 2b is... green Greater than the hydrogen production power command P EC When it is confirmed that the energy storage device 5 is not allowed to be charged, the controller 37 selects the first power generation device 2a and the second power generation device 2b to simultaneously supply power to the hydrogen production device 4 and the power grid 21. At this time, the energy storage device 5 does not participate in power conversion and transmission. For the sake of simplifying the diagram, it is omitted. Figure 3E The energy storage control unit 374 is omitted. (By...) Figure 3E It is known that in the first power supply mode under grid connection, the electrical energy generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b) is used to supply the hydrogen production device 4 to produce hydrogen, so as to provide the power required by the hydrogen production device, and at the same time supply power to the grid 21.

[0084] Please see Figure 3F and cooperate Figure 2 ,in Figure 3F for Figure 2 The diagram shows the power transmission path and control block diagram of the power system under the second power supply mode in grid-connected conditions. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal, confirming that the grid 21 is connected to the AC bus 20 (i.e., in grid-connected condition). Next, the mode selection unit 371 selects the total output power (P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Less than the hydrogen production power command P EC When it is confirmed that the energy storage device 5 is not allowed to discharge, the first power generation device 2a, the second power generation device 2b, and the power grid 21 are selected to simultaneously supply power to the hydrogen production device 4. At this time, the AC terminal power of the AC / DC converter 34 is the total output power of the first power generation device 2a and the second power generation device 2b (i.e., P). green =P pv +P windIn addition to the power provided by the power grid 21, the power transmission path and control method for powering the hydrogen production unit 4 are similar to those of the power grid 21. Figure 3A The power transmission path and control method shown will not be described again here. When in grid-connected mode, and wind and sunlight conditions do not meet hydrogen production requirements, the total power output P of the first power generation unit 2a and the second power generation unit 2b... green Less than the hydrogen production power command P EC When it is confirmed that the energy storage device 5 is not allowed to discharge, the controller 37 selects the first power generation device 2a, the second power generation device 2b, and the power grid 21 to simultaneously supply power to the hydrogen production device 4. At this time, the energy storage device 5 does not participate in power conversion and transmission. (This is omitted for simplicity in the diagram.) Figure 3F The energy storage control unit 374 is omitted. (By...) Figure 3F It is understood that in the second power supply mode under grid connection, the electrical energy generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b) and the electrical energy generated by the power grid 21 are used to supply the hydrogen production device 4 to produce hydrogen, so as to provide the power required by the hydrogen production device.

[0085] Please see Figure 3G and cooperate Figure 2 ,in Figure 3G for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the third power supply mode under grid connection. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal and confirms that the grid 21 is connected to the AC bus 20 (i.e., under grid connection). Next, the mode selection unit 371 selects the total output power (i.e., P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Greater than the hydrogen production power command P EC When it is confirmed that the energy storage device 5 is allowed to be charged, the first power generation device 2a, the second power generation device 2b, and the power grid 21 are selected to simultaneously supply power to the hydrogen production device 4 and the energy storage device 5. The power transmission path and control method for supplying power to the hydrogen production device 4 are similar to those of the first power generation device 2a, the second power generation device 2b, and the power grid 21. Figure 3C The power transmission path and control method shown will not be described again here. When in grid-connected condition, with good wind and sunlight conditions, and the total output power P of the first power generation device 2a and the second power generation device 2b... green Greater than the hydrogen production power command P EC When the energy storage device 5 is confirmed to be ready for charging, the controller 37 selects the first power generation device 2a, the second power generation device 2b, and the power grid 21 to simultaneously supply power to the hydrogen production device 4 and the energy storage device 5. Figure 3FIt can be seen that in the third power supply mode under grid connection, the electricity generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b) and the electricity generated by the power grid 21 are used to supply the hydrogen production device 4 to produce hydrogen, so as to provide the power required by the hydrogen production device and supply power to the energy storage device 5.

[0086] In another embodiment, when the electricity price of the power grid 21 is high, or during peak electricity consumption, or when green hydrogen production is desired, and the power system 1 is in the third power supply mode under grid connection, the power grid 21 does not participate in power supply, or the power of the first power generation device 2a and the second power generation device 2b are simultaneously supplied to the power grid 21 to complete grid-connected power generation.

[0087] Please see Figure 3H and cooperate Figure 2 ,in Figure 3H for Figure 2 The diagram shows the power transmission path and control block diagram of the power system in the fourth power supply mode under grid connection. First, the mode selection unit 371 determines the state of the grid 21 based on the grid signal and confirms that the grid 21 is connected to the AC bus 20 (i.e., under grid connection). Next, the mode selection unit 371 selects the total output power (i.e., P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare and confirm the total output power P green Less than the hydrogen production power command P EC And when it is confirmed that the energy storage device 5 is allowed to discharge, the first power generation device 2a, the second power generation device 2b, the power grid 21, and the energy storage device 5 are selected to simultaneously supply power to the hydrogen production device 4. The power transmission path and control method for supplying power to the hydrogen production device 4 are similar to those of... Figure 3D The power transmission path and control method shown will not be described again here. When in grid-connected mode, and wind and sunlight conditions do not meet hydrogen production requirements, the total power output P of the first power generation unit 2a and the second power generation unit 2b... green Less than the hydrogen production power command P EC When the energy storage device 5 is confirmed to be able to discharge, the controller 37 selects the first power generation device 2a, the second power generation device 2b, the power grid 21, and the energy storage device 5 to simultaneously supply power to the hydrogen production device 4. Figure 3G It can be seen that in the fourth power supply mode under grid connection, the electricity generated by renewable energy (i.e., the first power generation device 2a and the second power generation device 2b), the electricity generated by the power grid 21 and the electricity generated by the energy storage device 5 are simultaneously used to supply the hydrogen production device 4 to produce hydrogen, so as to provide the power required by the hydrogen production device.

[0088] In some embodiments, Figure 2The energy storage element 52 can also be a photovoltaic panel. In this case, there is only a discharge mode between the energy storage device 5 and the hydrogen production device 3, and no charging mode.

[0089] Please see Figure 4 , it is Figure 1 The diagram shows a detailed circuit topology of a second embodiment of the power system. Compared to... Figure 2 The hydrogen production power supply device 3 of the power system 1 shown includes an AC / DC converter 34 and a DC / DC converter 35. In this embodiment, the hydrogen production power supply device 3a of the power system 1a only includes the AC / DC converter 34. Therefore, the AC / DC converter 34 of the hydrogen production power supply device 3a and the energy storage converter 51 of the energy storage device 5 are electrically connected to the hydrogen production device 4. In this embodiment, the hydrogen production power supply device 3a only uses a single-stage converter for AC / DC conversion, thus improving hydrogen production efficiency. Furthermore, the controller 37 in this embodiment may also correspondingly omit the DC / DC control unit. In addition, since the AC / DC converter 34 is a boost converter, the DC terminal voltage of the AC / DC converter 34 must be higher than the AC terminal voltage. However, the port voltage of the hydrogen production device 4 during startup is lower than the DC terminal voltage of the AC / DC converter 34. Therefore, the AC / DC converter 34 cannot operate during the startup phase of the hydrogen production device 4. Before the hydrogen production unit 4 is started, the AC or DC terminal switch of the AC / DC converter 34 needs to be opened. The energy storage element 52 supplies power to the hydrogen production unit 4 via the energy storage converter 51 to control the current or voltage of the hydrogen production unit 4 to gradually increase. When the voltage of the hydrogen production unit 4 reaches the minimum voltage that allows the AC / DC converter 34 to start, the AC and DC terminals of the AC / DC converter 34 are closed, and the control signal is adjusted to control the power of the AC or DC terminal of the AC / DC converter 34. At the same time, the energy storage converter 51 controls the charging and discharging power of the energy storage element 52.

[0090] In this embodiment, the hydrogen production and power supply device 3a of the power system 1a operates in different power supply modes, whether off-grid or grid-connected, similar to... Figures 3A to 3H The power supply mode of the hydrogen production and power supply device 3 in the power system 1 is corresponding to the off-grid or grid-connected conditions. In different power supply modes in this embodiment, when the AC / DC converter 34 is running, the AC / DC control unit 372 is used to control the current or power of the DC and AC terminals of the AC / DC converter 34; and when the energy storage converter 51 is running, the energy storage control unit 374 is used to control the output current or power of the hydrogen production and power supply device 3.

[0091] Please see Figure 5 , it is Figure 1 The diagram shows a detailed circuit topology of a third embodiment of the power system. Compared to... Figure 2The energy storage device 5 of the power system 1 shown includes an energy storage converter 51 and an energy storage element 52. In this embodiment, the energy storage device 5 of the power system 1b only includes the energy storage element 52 and does not include the energy storage converter. The energy storage element 52 of the energy storage device 5 is electrically connected to the connection line between the AC / DC converter 34 and the DC / DC converter 35, i.e., the DC coupling terminal 33. In this embodiment, the hydrogen production and power supply device 3b directly supports the bus voltage between the AC / DC converter 34 and the DC / DC converter 35 by the energy storage device 5, and the energy storage converter connected to the energy storage device 5 can be omitted. Correspondingly, the controller 37 of this embodiment may not include an energy storage control unit.

[0092] In this embodiment, the hydrogen production and power supply device 3b of the power system 1b operates in different power supply modes, whether off-grid or on-grid. Figures 3A to 3H The power supply mode of the hydrogen production and power supply device 3 in the power system 1 is corresponding to the off-grid or grid-connected conditions. In different power supply modes in this embodiment, when the AC / DC converter 34 is running, the AC / DC control unit 372 is used to control the power or bus voltage of the AC terminal of the AC / DC converter 34; and when the DC / DC converter 35 is running, the DC / DC control unit 373 is used to control the output current or power of the hydrogen production and power supply device 3.

[0093] In some embodiments, the hydrogen production and power supply device and the energy storage device are mechanically attached to a DC terminal to form a DC-coupled hydrogen production system. This DC-coupled hydrogen production system can also integrate a DC photovoltaic power generation device to form a photovoltaic-storage-hydrogen multi-port energy network. Please refer to [link to relevant documentation]. Figure 6 , it is Figure 1 The diagram shows a detailed circuit topology of a fourth embodiment of the power system. Compared to... Figure 2The energy storage device 5 of the power system 1 shown includes only a single energy storage converter 51 and a single energy storage element 52. In this embodiment, the energy storage device 5 of the power system 1c further includes an additional energy storage converter (hereinafter referred to as the original energy storage converter 51, and the additional energy storage converter as the second energy storage converter 53) and another energy storage element (e.g., a second photovoltaic panel 54). One end of the second energy storage converter 53 is electrically connected to the DC coupling terminal 33 of the hydrogen production and power supply device 3c, and the other end of the second energy storage converter 53 is electrically connected to the second photovoltaic panel 54. The electrical energy provided by the second photovoltaic panel 54 can be transmitted to the DC coupling terminal 33 via the second energy storage converter 53 to stabilize the DC bus voltage or control the charging power of its hydrogen production and energy storage device 5. In one embodiment, the second photovoltaic panel 54 and the energy storage element 52 can provide each other with electrical energy. For example, when sunlight conditions are good during the day, the second photovoltaic panel 54 can provide excess energy to charge the energy storage element 52 or transmit it back to the grid 21, thereby reducing the energy demand on the energy storage element 52 and the grid 21 during hydrogen production, extending the service life of the energy storage element 52, and reducing the cost of purchasing electricity from the grid 21. Furthermore, since hydrogen production is carried out using the second photovoltaic panel 54, the losses of converter step-down or rectification can be reduced to improve energy conversion efficiency. Therefore, this embodiment is suitable for photovoltaic power plants using DC grids or for applications where photovoltaics can be integrated locally in hydrogen production stations.

[0094] Of course, the energy storage device described above can also be applied to similar applications. Figure 4 Please refer to the power system shown. Figure 7 , it is Figure 1 The diagram shows a detailed circuit topology of the fifth embodiment of the power system. Compared to... Figure 6 The power system 1c shown in this embodiment has a hydrogen production power supply device 3d that only includes an AC / DC converter 34. Therefore, the AC / DC converter 34 of the hydrogen production power supply device 3d and the energy storage converters 51 and 53 of the energy storage device 5 are electrically connected to the hydrogen production device 4. The hydrogen production power supply device 3d in this embodiment only uses a single-stage converter for AC / DC conversion, thus improving the hydrogen production efficiency. Furthermore, the controller 37 in this embodiment may also not include a DC / DC control unit.

[0095] Please see Figure 8 , it is Figure 1 The diagram shows a detailed circuit topology of the sixth embodiment of the power system. Compared to... Figure 6 The power system 1c shown in this embodiment has an energy storage device 5 that includes only an energy storage element 52, a second energy storage converter 53 and a second photovoltaic panel 54, but does not include a first energy storage converter. In other words, the energy storage element 52 can be directly connected to the DC coupling terminal 33 of the hydrogen production power supply device 3.

[0096] Please see Figure 9 , it is Figure 1 The diagram shows a detailed circuit topology of the seventh embodiment of the power system. Compared to... Figure 2 The energy storage device 5 of the power system 1 shown only includes a single energy storage converter 51 and a single energy storage element 52. The energy storage device 5 of the power system 1f in this embodiment further includes an additional photovoltaic panel (hereinafter referred to as the second photovoltaic panel 54), which is electrically connected to the DC coupling terminal 33 of the hydrogen production power supply device 3c.

[0097] Figure 10A and 10B This is a flowchart of the power system control method in this case. First, step S1 is executed to detect a first parameter and a second parameter. The first parameter can be the grid signal of the grid 21, the output power signal of the first generator 2a, the output power signal of the second generator 2b, the status signal of the hydrogen production device 4, and the hydrogen production power command. The second parameter can be a parameter in the power transmission path. Next, step S2 is executed to confirm whether the grid 21 is connected to the AC bus 20 of the power system 1. If the confirmation result of step S2 is negative, that is, the grid 21 is not connected to the AC bus 20 of the power system 1 (in the off-grid situation), step S3 is executed to compare the total output power (i.e., P) of the first generator 2a and the second generator 2b. green =P pv +P wind ) and hydrogen production power command P EC That is, compare the total output power P green Is it greater than or equal to the hydrogen production power command P? EC When the comparison result of step S3 is yes, that is, the total output power P green Greater than or equal to hydrogen production power command P EC Execute step S4 to confirm the total output power P. green Is it equal to the hydrogen production power command P? EC When the confirmation result of step S4 is yes, that is, the total output power P is confirmed. green Equal to hydrogen production power command P EC When step S5 is executed, the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production and power supply unit 3 are controlled to operate, so that the first power generation unit 2a and the second power generation unit 2b can provide the power required by the hydrogen production unit 4. When the confirmation result of step S4 is negative, that is, the total output power P is confirmed. green Greater than the hydrogen production power command P ECWhen step S6 is executed, the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production and power supply device 3 and the energy storage converter 51 of the energy storage device 5 are controlled to operate, so that the first power generation device 2a and the second power generation device 2b provide the power required by the hydrogen production device 4, and simultaneously provide power to the energy storage element 52 of the energy storage device 5 for charging. When the comparison result of step S3 is negative, that is, the total output power P green Less than the hydrogen production power command P EC Execute step S7 to confirm the total output power P green Is it greater than 0? If the confirmation result of step S7 is yes, then the total output power P is confirmed. green When the value is greater than 0, step S8 is executed, controlling the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production and power supply device 3 and the energy storage converter 51 of the energy storage device 5 to operate, so that the first power generation device 2a, the second power generation device 2b and the energy storage element 52 of the energy storage device 5 simultaneously provide the power required by the hydrogen production device 4. When the confirmation result of step S7 is negative, that is, the total output power P is confirmed. green When the output power is equal to 0, step S9 is executed, controlling the operation of the DC / DC converter 35 of the hydrogen production and power supply device 3 and the energy storage converter 51 of the energy storage device 5, so that the energy storage element 52 of the energy storage device 5 provides the power required by the hydrogen production device 4. When the confirmation result of step S2 is yes, that is, the power grid 21 is electrically connected to the AC bus 20 of the power system 1 (in the grid-connected case), step S10 is executed, comparing the total output power (i.e., P) of the first power generation device 2a and the second power generation device 2b. green =P pv +P wind ) and hydrogen production power command P EC Compare the total output power P green Is it greater than or equal to the hydrogen production power command P? EC When the comparison result of step S10 is yes, that is, the total output power P green Greater than or equal to hydrogen production power command P ECStep S11 is executed to confirm whether the energy storage device 5 is allowed to be charged. If the confirmation result of step S11 is yes, that is, it is confirmed that the energy storage device 5 is allowed to be charged, step S12 is executed to control the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production and power supply device 3 and the energy storage converter 51 of the energy storage device 5 to operate, so that the first power generation device 2a, the second power generation device 2b and the power grid 21 provide the power required by the hydrogen production device 4, and at the same time provide power to the energy storage element 52 of the energy storage device 5 for charging. If the confirmation result of step S11 is no, that is, it is confirmed that the energy storage device 5 is not allowed to be charged, step S13 is executed to control the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production and power supply device 3, so that the first power generation device 2a and the second power generation device 2b provide the power required by the hydrogen production device 4, and at the same time supply power to the power grid 21. If the comparison result of step S10 is no, that is, the total output power P green Less than the hydrogen production power command P EC Step S14 is executed to confirm whether the energy storage device 5 is allowed to discharge. If the confirmation result of step S14 is negative, i.e., the energy storage device 5 is not allowed to discharge, step S15 is executed to control the operation of the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production power supply device 3, so that the first power generation device 2a, the second power generation device 2b, and the power grid provide the power required by the hydrogen production device 4. If the confirmation result of step S14 is positive, i.e., the energy storage device 5 is allowed to discharge, step S16 is executed to control the operation of the AC / DC converter 34 and DC / DC converter 35 of the hydrogen production power supply device 3 and the energy storage converter 51 of the energy storage device 5, so that the first power generation device 2a, the second power generation device 2b, the power grid 21, and the energy storage element 52 of the energy storage device 5 simultaneously provide the power required by the hydrogen production device 4. In other words, the power system of this case selects the power source to supply the hydrogen production device based on the confirmation result of step S2, the comparison results of steps S3 and S10, and the confirmation results of steps S11 and S13.

[0098] It should be noted that the above method and steps are only one example. When the architecture, application scenario, or design requirements change, one or more of these steps will be adjusted accordingly. For example, when the output power of the first power generation device 2a and the second power generation device 2b is high, the energy storage element 52 is not allowed to charge, and the power grid 21 is not allowed to generate electricity in parallel with the grid or is in an off-grid state, power limiting control can be implemented on the first power generation device 2a and the second power generation device 2b to reduce their actual output power.

[0099] According to the above control method, the minimum power provided by the energy storage device 5 should be higher than the minimum load required by the hydrogen production device 4, for example, 20% of the rated load Pr of the hydrogen production device 4, i.e., 0.2Pr. This ensures that when the power supplied by the wind turbine 22 of the first power generation device 2a and the photovoltaic inverter 23 of the second power generation device 2b, or the power supplied by the power grid 21, is suddenly interrupted, the power provided by the energy storage device 5 can continue to produce hydrogen under the minimum load required by the hydrogen production device 4, and wait for the wind turbine 22 of the first power generation device 2a and the photovoltaic inverter 23 of the second power generation device 2b, or the power grid 21, to restore power supply. The maximum power provided by the energy storage device 5 can be equal to the maximum load of the hydrogen production device 4, for example, 110% of the rated load Pr of the hydrogen production device 4, i.e., 1.1Pr, so that the hydrogen production device 4 can produce hydrogen quickly. In one embodiment, the capacity of the energy storage device 5 can be adjusted according to the actual hydrogen production and the power interruption time of the wind turbine 22 of the first power generation device 2a and the photovoltaic inverter 23 of the second power generation device 2b. The power system of this invention can achieve energy dispatch in different modes according to the above control method, so that the hydrogen production device 4 can maintain high-efficiency operation, or maintain at least the minimum load required for hydrogen production in complete darkness, and ensure the hydrogen production efficiency and purity of the hydrogen production device 4. In one embodiment, the power system of this invention can switch to a suitable mode for hydrogen production according to the real-time electricity price of the grid 21 and the cost of the energy storage device 5, thereby reducing the cost of hydrogen production.

[0100] In this embodiment, the power system can communicate with the wind turbine 22 of the first power generation device 2a and / or the photovoltaic inverter 23 of the second power generation device 2b in three ways. The first communication method is high-speed site communication via interconnection cables, where the power system can communicate with the wind turbine 22 of the first power generation device 2a and / or the photovoltaic inverter 23 of the second power generation device 2b via communication cables. The second communication method is power line carrier communication, where the sender between the power system and the wind turbine 22 of the first power generation device 2a and / or the photovoltaic inverter 23 of the second power generation device 2b modulates the communication data at high frequency and transmits it over the power line; the receiver between the power system and the wind turbine 22 of the first power generation device 2a and / or the photovoltaic inverter 23 of the second power generation device 2b then modulates and separates the high-frequency communication data. The third communication method involves the power system using an AC / DC converter 34 to adjust the frequency of the AC bus voltage of the AC bus 20 according to the power required by the hydrogen production unit 4. When the wind turbine converter 22 of the first power generation unit 2a and / or the photovoltaic inverter 23 of the second power generation unit 2b detects a change in the frequency of the AC bus voltage, they can adjust the power supplied to the AC bus 20 by the wind turbine converter 22 of the first power generation unit 2a and / or the photovoltaic inverter 23 of the second power generation unit 2b according to the relationship between the corresponding frequency and power. The relationship curve between the power of the wind turbine converter 22 of the first power generation unit 2a and / or the photovoltaic inverter 23 of the second power generation unit 2b and the frequency of the AC bus 20 is shown in the figure below. Figure 11 As shown. When the power system uses the third communication method, no new interconnecting lines are needed; only the original power transmission lines are required, thereby reducing costs and offering advantages such as reduced difficulty in regulation and improved ease of implementation.

[0101] In summary, this invention provides a power system and its control method, wherein the power system determines an operating mode based on the state and parameters of one or more of a power source, an energy storage device, and a hydrogen production device, selects a power source for hydrogen production and a corresponding power transmission path, utilizes the selected power source to provide electrical energy, and performs power conversion and transmission through the selected power transmission path to provide the electrical energy required by the hydrogen production device. The selected optimal power source and power transmission path can supply power to the hydrogen production device in a stable, continuous, efficient, and low-cost manner.

Claims

1. An electrical system for supplying power to a hydrogen production unit, wherein the electrical system comprises: Multiple power supplies; An energy storage device; and A hydrogen production and power supply device has an AC terminal, a DC output terminal, a DC coupling terminal and a controller. The AC terminal is electrically connected to a plurality of power sources through an AC bus. The DC output terminal is electrically connected to the hydrogen production device and the DC coupling terminal is electrically connected to the energy storage device. The controller determines the operating mode according to the status and parameters of the plurality of power sources, the energy storage device and / or the hydrogen production device, and selectively receives and converts the electrical energy provided by at least one of the plurality of power sources and / or the energy storage device to supply power to the hydrogen production device using at least one power transmission path. in, The hydrogen production and power supply device and / or the energy storage device provide the at least one power transmission path.

2. The power system of claim 1, wherein there are multiple power transmission paths between the plurality of power sources and the hydrogen production device, each power transmission path including at least one power converter, the at least one power converter being used to realize power conversion and transmission in the corresponding power transmission path.

3. The power system of claim 2, wherein the controller comprises: A mode selection unit, electrically connected to the plurality of power sources and the hydrogen production device, is configured to: receive a plurality of first parameters, determine, based on the plurality of first parameters, the power source supplying the hydrogen production device, and generate a plurality of power commands; and Multiple power control units, each of which is electrically connected to the mode selection unit, a corresponding power transmission path, and a corresponding power converter, are configured to: receive multiple second parameters and at least one power command, and control the operation of the corresponding power converter according to the multiple second parameters and at least one power command, so that the corresponding power transmission path provides power to the hydrogen production device.

4. The power system as described in claim 3, wherein the plurality of first parameters correspond to the power parameters of the plurality of power sources and the hydrogen production device, and the plurality of second parameters correspond to the power parameters in the plurality of power transmission paths.

5. The power system as claimed in claim 3, wherein the plurality of power sources includes a first power generation device, a second power generation device, and a power grid, wherein the first power generation device, the second power generation device, and the power grid are respectively electrically connected to the AC bus.

6. The power system of claim 5, wherein the mode selection unit is further configured to: receive an output power signal of the first power generation device, an output power signal of the second power generation device, a status signal of the hydrogen production device, a grid signal of the power grid and / or a hydrogen production power command; determine the grid status based on the grid signal; compare the total output power of the first power generation device and the second power generation device with the hydrogen production power command to obtain a comparison result; and select at least one power source from the plurality of power sources based on the determined grid status and the comparison result.

7. The power system of claim 6, wherein the hydrogen production and power supply device comprises an AC / DC converter and a DC / DC converter, the AC / DC converter being electrically connected to the AC terminal, the DC / DC converter being electrically connected between the AC / DC converter and the DC output terminal, the AC / DC converter and the DC / DC converter being electrically connected to the DC coupling terminal, and the energy storage device comprising an energy storage converter and an energy storage element, the energy storage converter being electrically connected between the DC coupling terminal and the energy storage element.

8. The power system of claim 6, wherein the hydrogen production and power supply device includes an AC / DC converter electrically connected between the AC terminal and the DC coupling terminal, and the energy storage device includes an energy storage converter and an energy storage element, wherein the energy storage converter is electrically connected between the DC coupling terminal and the energy storage element.

9. The power system as claimed in claim 7 or 8, wherein the energy storage device further comprises another energy storage converter and a photovoltaic element, the other energy storage converter being electrically connected between the DC coupling terminal and the photovoltaic element.

10. The power system of claim 7, wherein the plurality of power control units comprises: An AC / DC control unit is configured to: receive at least one of the plurality of power commands, the AC voltage and AC current of the AC terminal and / or the DC bus voltage of the DC coupling terminal, and output a first control signal to control the operation of the AC / DC converter; A DC / DC control unit is configured to: receive at least one of the plurality of power commands, the output voltage and / or output current of the DC output terminal, and output a second control signal to control the operation of the DC / DC converter; as well as An energy storage control unit is configured to receive the voltage and current of the energy storage element and / or the DC bus voltage of the DC coupling terminal, and output a third control signal to control the operation of the energy storage converter.

11. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is not connected to the AC bus and the total output power of the first power generation device and the second power generation device is equal to the hydrogen production power command, it selects the first power generation device and the second power generation device to provide the power required by the hydrogen production device.

12. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is not connected to the AC bus and the total output power of the first power generation device and the second power generation device is greater than the hydrogen production power command, it selects the first power generation device and the second power generation device to provide the power required by the hydrogen production device, and simultaneously charges an energy storage element of the energy storage device.

13. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is not connected to the AC bus, and when the total output power of the first power generation device and the second power generation device is less than the hydrogen production power command, and the total output power is greater than 0, the first power generation device, the second power generation device, and the energy storage device are selected to provide the power required by the hydrogen production device.

14. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is not connected to the AC bus and the total output power of the first power generation device and the second power generation device is equal to 0, it selects the energy storage device to provide the power required by the hydrogen production device.

15. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is electrically connected to the AC bus, the total output power is greater than or equal to the hydrogen production power command, and the energy storage device is allowed to charge, it selects the first power generation device, the second power generation device, and the power grid to provide the power required by the hydrogen production device, and simultaneously charges an energy storage element of the energy storage device.

16. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is electrically connected to the AC bus, the total output power is greater than or equal to the hydrogen production power command, and the energy storage device is not allowed to be charged, it selects the first power generation device and the second power generation device to provide the power required by the hydrogen production device, and simultaneously provides power to the power grid.

17. The power system of claim 6, wherein when the mode selection unit confirms that the power grid is electrically connected to the AC bus, the total output power is less than the hydrogen production power command, and the energy storage device is not allowed to discharge, it selects the first power generation device, the second power generation device, and the power grid to provide the power required by the hydrogen production device.

18. The power system of claim 6, wherein the mode selection unit selects the first power generation device, the second power generation device, the power grid, and the energy storage device to provide the power required by the hydrogen production device when the power grid is electrically connected to the AC bus, the total output power is less than the hydrogen production power command, and the energy storage device is allowed to discharge.

19. The power system of claim 1, wherein when the total output power of the plurality of power sources is less than the hydrogen production power command of the hydrogen production device, the hydrogen production power supply device and the energy storage device jointly provide multiple power transmission paths to power the hydrogen production device; when the total output power of the plurality of power sources is greater than or equal to the hydrogen production power command, the hydrogen production power supply device provides the at least one power transmission path to power the hydrogen production device.

20. A DC coupling device, comprising: An energy storage device; and A power supply device has an AC terminal, a DC output terminal, a DC coupling terminal and a controller. The AC terminal is electrically connected to at least one power source through an AC bus, the DC output terminal is electrically connected to an electrical load, and the DC coupling terminal is electrically connected to the energy storage device. The controller determines the operating mode based on the status and parameters of the at least one power source, the energy storage device and / or the power load, and selectively receives and converts the power provided by the at least one power source and / or the energy storage device to supply power to the power load using a power transmission path. in, The power supply device and / or the energy storage device provide the at least one power transmission path.

21. The DC coupling device of claim 20, wherein there are multiple power transmission paths between the at least one power source and the power load, each power transmission path including at least one power converter for realizing power conversion and transmission in the corresponding power transmission path.

22. The DC coupling device of claim 21, wherein the controller comprises: A mode selection unit, electrically connected to the at least one power source and the power load, is configured to: receive a plurality of first parameters, determine, based on the first parameters, a power source for supplying power to the power load, and generate a plurality of power commands; and Multiple power control units, each of which is electrically connected to the mode selection unit, the corresponding power transmission path, and the corresponding power converter, are configured to: receive multiple second parameters and at least one power command, and control the operation of the corresponding power converter according to the multiple second parameters and at least one power command, so that the corresponding power transmission path provides power to the power load.

23. The DC coupling device as claimed in claim 22, wherein the plurality of first parameters correspond to the power parameters of the plurality of power sources and the power supply device, and the plurality of second parameters correspond to the power parameters in the plurality of power transmission paths.

24. The DC coupling device of claim 22, wherein the power supply device includes an AC / DC converter and a DC / DC converter, the AC / DC converter being electrically connected to the AC terminal, the DC / DC converter being electrically connected between the AC / DC converter and the DC output terminal, the AC / DC converter and the DC / DC converter being electrically connected to the DC coupling terminal, and the energy storage device including an energy storage converter and an energy storage element, the energy storage converter being electrically connected between the DC coupling terminal and the energy storage element.

25. The DC coupling device of claim 22, wherein the power supply device includes an AC / DC converter electrically connected between the AC terminal and the DC coupling terminal, and the energy storage device includes an energy storage converter and an energy storage element, wherein the energy storage converter is electrically connected between the DC coupling terminal and the energy storage element.

26. The DC-coupled device as claimed in claim 24 or 25, wherein the energy storage device further comprises another energy storage converter and a photovoltaic element, the other energy storage converter being electrically connected between the DC-coupled terminal and the photovoltaic element.

27. The DC coupling device of claim 20, wherein when the total output power of the at least one power source is less than the power command of the power load, the power supply device and the energy storage device jointly provide multiple power transmission paths to supply power to the power load; when the total output power of the at least one power source is greater than or equal to the power command of the power load, the power supply device provides the at least one power transmission path to supply power to the power load.

28. A control method applied to an electric power system for supplying power to a hydrogen production unit, wherein the control method comprises: (a) A plurality of power sources, an energy storage device, and a hydrogen production and power supply device are provided. The hydrogen production and power supply device has an AC terminal, a DC output terminal, and a DC coupling terminal. The AC terminal is electrically connected to the plurality of power sources via an AC bus. The DC output terminal is electrically connected to the hydrogen production device, and the DC coupling terminal is electrically connected to the energy storage device. (b) Determine the operating mode based on the status and parameters of the plurality of power sources, the energy storage device and / or the hydrogen production device, and selectively receive and convert the power provided by at least one of the plurality of power sources and / or the energy storage device to power the hydrogen production device using a power transmission path. in, The power supply device and / or the energy storage device provide the at least one power transmission path.

29. The control method of claim 28, wherein the plurality of power sources includes a power grid, a first power generation device, and a second power generation device, wherein step (b) further includes: (b1) Confirm whether the power grid is connected to the AC bus; (b2) Compare the total output power of the first power generation unit and the second power generation unit with the hydrogen production power command; (b3) Based on the confirmation result of step (b1) and the comparison result of step (b2), select the power source to supply the hydrogen production unit.

30. The control method of claim 29, wherein when the confirmation result of step (b1) is negative and the comparison result of step (b2) is that the total output power is equal to the hydrogen production power command, the hydrogen production power supply device is controlled to operate so that the first power generation device and the second power generation device provide the power required by the hydrogen production device.

31. The control method of claim 29, wherein when the confirmation result of step (b1) is negative and the comparison result of step (b2) is that the total output power is greater than the hydrogen production power command, the hydrogen production power supply device and the energy storage device are controlled to operate so that the first power generation device and the second power generation device provide the power required by the hydrogen production device, and at the same time charge an energy storage element of the energy storage device.

32. The control method of claim 29, wherein when the confirmation result of step (b1) is negative, and the comparison result of step (b2) is that the total output power is less than the hydrogen production power command and the total output power is greater than 0, the hydrogen production power supply device and the energy storage device are controlled to operate so that the first power generation device, the second power generation device and the energy storage device provide the power required by the hydrogen production device.

33. The control method of claim 29, wherein when the confirmation result of step (b1) is negative and the comparison result of step (b2) is that the total output power is equal to 0, the hydrogen production power supply device and the energy storage device are controlled to operate so that the energy storage device provides the power required by the hydrogen production device.

34. The control method of claim 29, wherein step (b) further includes step (b4) to confirm whether the energy storage device is allowed to charge and discharge, wherein step (b3) further selects a power source to supply power to the hydrogen production device based on the confirmation result of step (b1), the comparison result of step (b2), and the confirmation result of step (b4).

35. The control method of claim 34, wherein when the confirmation result of step (b1) is yes, the comparison result of step (b2) is that the total output power is greater than or equal to the hydrogen production power command, and the confirmation result of step (b4) is that the energy storage device is allowed to be charged, the hydrogen production power supply device and the energy storage device are controlled to operate so that the first power generation device, the second power generation device and the power grid provide the power required by the hydrogen production device, and at the same time charge an energy storage element of the energy storage device.

36. The control method as described in claim 34, wherein when the confirmation result of step (b1) is yes, the comparison result of step (b2) is that the total output power is greater than or equal to the hydrogen production power command, and the confirmation result of step (b4) is that the energy storage device is not allowed to charge, the hydrogen production power supply device is controlled to operate so that the first power generation device and the second power generation device provide the power required by the hydrogen production device and simultaneously supply power to the power grid.

37. The control method of claim 34, wherein when the confirmation result of step (b1) is yes, the comparison result of step (b2) is that the total output power is less than the hydrogen production power command, and the confirmation result of step (b4) is that the energy storage device is not allowed to discharge, the hydrogen production power supply device is controlled to operate so that the first power generation device, the second power generation device and the power grid provide the power required by the hydrogen production device.

38. The control method of claim 34, wherein when the confirmation result of step (b1) is yes, the comparison result of step (b2) is that the total output power is less than the hydrogen production power command, and the confirmation result of step (b4) is that the energy storage device is allowed to discharge, the hydrogen production power supply device and the energy storage device are controlled to operate so that the first power generation device, the second power generation device, the power grid and the energy storage device simultaneously provide the power required by the hydrogen production device.

39. The control method of claim 28, wherein when the total output power of the plurality of power sources is less than the hydrogen production power command of the hydrogen production device, the power supply device and the energy storage device jointly provide multiple power transmission paths to power the hydrogen production device; when the total output power of the plurality of power sources is greater than or equal to the hydrogen production power command, the power supply device provides the at least one power transmission path to power the hydrogen production device.

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