Decentralised energy management

Abstract

The invention relates to a method for energy supply in an isolated network (1), the isolated network (1) comprising a first electrical energy supply module (6) and a second electrical energy supply module (7), in each of which energy is both provided directly by a battery (8) and by a fuel cell (9) via a DC / DC converter (9) and provided by the battery (8) and fuel cell (10) jointly, wherein electrical energy sources (4) of the isolated network (1) each calculate their own setpoint on the basis of the data from the respectively other electrical energy sources (4) and from the electrical loads (5) and communicate this setpoint to the respectively other energy sources (4), wherein, if required, the operating status of the first electrical energy supply module (6) is changed such that it is no longer available for the network supply, and the battery (8) of the first energy supply module (6) is charged to a previously determined charge state, wherein, in parallel therewith, the operating status of the second electrical energy supply module (7) is changed such that it is available for the network supply in order to cover a requested network load. The invention also relates to an isolated network (1).

Description

[0001] Description

[0002] Decentralized energy management

[0003] The invention relates to a method for energy supply in an island network and to an island network.

[0004] Island grids, e.g., on ships, especially special-purpose vessels or even onshore installations, require high grid availability to avoid increased risks for the operational operations being performed (e.g., dynamic positioning of ships, work on offshore facilities, power supply to computer systems, etc.) even in the event of partial system or subsystem failures. Environmental regulations are also increasing the demands for efficiency and the avoidance of harmful emissions. This is increasingly leading to a preferential consideration of fuel cells and energy storage systems for maintaining and providing the required energy for electric drives, e.g., for ship propulsion, and other highly available units and components.Since the characteristics of the fuel cell as an energy converter differ from those of traditional generator sets, the system design and the associated control must meet the new requirements in terms of operational reliability, availability and service life.

[0005] Energy storage devices such as batteries are fed into or charged from an AC grid via bidirectional DC / AC converters. In the DC grid, batteries are sometimes connected directly to the DC bus or via DC / DC controllers. With direct coupling, the energy flow follows the state of charge of the battery versus the intermediate circuit voltage, whereby the intermediate circuit voltage must be set according to the battery requirements. The converter (AC / DC or DC / DC) actively charges and discharges according to the state of charge (SOC) of the storage devices specified by the central Power Management System (PMS) or the control system. Fuel cells are controlled either by a PMS via the load requirement from the grid or via the state of charge of the battery (SOG). The dynamics of changing loads have a negative impact on the service life of the fuel cells.

[0006] Therefore, the load requirements on the fuel cells are often dampened with energy storage devices (batteries), as disclosed in US 11,621,432 B2.

[0007] The object of the invention is to provide a method for supplying energy in an island grid using fuel cells and batteries as electrical energy sources, particularly with regard to the service life of the components involved. A further object of the invention is to specify a corresponding island grid.

[0008] The invention solves the problem directed to a method for energy supply in an island network with fuel cells and batteries as electrical energy sources by providing that in such a method for energy supply in an island network, the island network comprising electrical lines and a plurality of electrical units which can be coupled to the electrical lines and which can be electrical energy sources or electrical loads, wherein the electrical energy sources comprise a first electrical energy supply module and a second electrical energy supply module, in each of which energy is provided both directly from a battery and via a DC / DC converter from a fuel cell, as well as jointly from the battery and fuel cell, wherein the electrical energy sources of the island network each provide the other electrical energy sources in the island network with data such as their respective actual values,Announce reserves and minimum setpoints, whereby the electrical loads of the island grid announce data such as their actual value and their achievable maximum value in the island grid, and whereby the electrical energy sources of the island grid each calculate their own setpoint based on the data of the other electrical energy sources and the electrical loads and communicate this setpoint to the other electrical energy sources, whereby a charge level of the battery of the first electrical energy supply module is determined and an operating point of its fuel cell or an operating point of its DC / DC converter is controlled depending on the charge level of its battery, whereby if the battery of the first electrical energy supply module falls below a lower charge limit, the power of the fuel cell of the first electrical energy supply module is increased,until the battery of the first electrical power supply module changes to the state of charge or until the fuel cell of the first electrical power supply module has reached an upper power limit and, if this is not sufficient to charge the battery of the first electrical power supply module, the operating status of the first electrical power supply module is changed so that it is no longer available for the grid supply and the battery of the first power supply module is charged to a predetermined state of charge, wherein in parallel the operating status of the second electrical power supply module is changed so that it is available for the grid supply to cover a requested grid load.

[0009] In the present invention, the term "battery" is used in a broad sense, meaning that it is to be understood as a storage device for electrical energy on an electrochemical basis.

[0010] The invention is based on the assumption that, in an island grid, fuel cells and batteries are combined in one energy supply module, and that, within each energy supply module, the charge level of the battery is kept within a defined range by means of an energy management system, and excessive dynamics with regard to the fuel cell are avoided. Energy can be made available to the grid from the battery or another energy storage device, as well as from the fuel cell. If a maximum charge level is exceeded, the fuel cell is reduced to its minimum load, and energy is taken exclusively from the energy storage device. If the charge in the storage device falls below the minimum, the power of the fuel cell is increased until it has reached its maximum power.According to the invention, if the measures described are not sufficient to charge the battery, the operating status of the corresponding electrical energy supply module is set to "off" and the electrical energy supply module is not available to the island grid until a defined charge level is reached. In parallel, another electrical energy supply module is connected to the island grid to cover the requested grid load. When the defined charge level is reached, the operating status of the first electrical energy supply module is set back to "on" so that this electrical energy supply module is again available to supply the grid. This can be implemented particularly flexibly if the electrical units and in particular the electrical energy sources have the same information at all times and this information is stored locally, i.e.Each electrical unit is evaluated individually and using the same algorithms. With each registration of an electrical power supply module in the island grid, it receives correspondingly defined parameters from the other electrical power supply modules in the island grid (e.g., operating hours, theoretical remaining service life, etc.) and, if applicable, a priority, so that the electrical power supply modules are switched on according to the power requirements of the loads in the grid and according to their priority.

[0011] It is advantageous if, when the battery of the first electrical power supply module reaches an upper charge limit, the operating status of the first electrical power supply module is set so that it is available for supplying the grid again. By making the first power supply module available for supplying the grid again, a continuous power supply is more easily guaranteed. Power demand in the island grid can also vary depending on the time of day, weather conditions, or other factors. Once the first power supply module is available again, the grid can respond better to fluctuations in power demand.

[0012] Advantageously, data from one electrical unit is communicated to the other electrical units, or at least to the electrical energy sources, in a time-controlled manner and in cycles. The electrical units in the island grid are controlled on the basis of the data and using an algorithm available to the electrical units. Well-coordinated data transmission avoids potential overloads or bottlenecks. This helps maintain consistent system performance and ensures stable operation. All electrical units in the island grid can calculate their setpoints and adhere to their limits based on their own parameters and the parameters reported back from the other electrical units. There is no central calculation or control of the electrical units. The electrical units each calculate the applicable requirements for themselves.This works because the same relevant algorithms are used in each electrical unit.

[0013] It is useful if the prioritization of electrical units is adjusted dynamically. In a power grid, the requirements and loads can change over time. Dynamic prioritization enables grid managers to better balance loads and prevent bottlenecks. Prioritization can be adjusted to optimally handle peak load times or special requirements, for example by prioritizing critical components. Furthermore, energy sources and consumers in a modern power grid are often diverse and decentralized. Static prioritization could limit the grid's ability to respond to changing circumstances. Dynamic adaptation makes it possible to integrate new units or technologies into the grid and make optimal use of them.Particularly with regard to the integration of renewable energies such as wind and solar power into the power grid, the dynamics of power generation are becoming more variable. Dynamic prioritization can help balance fluctuations in power generation and maintain grid stability.

[0014] On a ship, it is advantageous to specify priorities by selecting a driving profile. For example, in a profile with maximum energy efficiency, corresponding energy sources could be given priority. The situation is different in maneuvering operations on naval ships. There, a reliable and stable energy source is necessary, even if this comes at the expense of the environment or the economy. The opposite is true in port, where only minimal emissions are tolerated. Various operating states can be stored as fixed modes, and the corresponding number of power units can be kept ready.

[0015] It is advisable to define the prioritization of the electrical units using a priority list. This priority list can be advantageously adjusted based on an evaluation of the electrical units' operating hours.

[0016] Advantageously, a redundancy requirement is defined, and if the supply falls below a specified limit in the island grid, the operating status of at least one unused electrical energy source is changed so that it is available for grid supply to meet the requested redundancy. By selecting the number and power levels of the electrical energy sources according to the expected operating profile, every operating state can be mapped with sufficient reliability in accordance with the specifications. At the same time, the fuel cells can be operated optimally (for their lifetime).

[0017] Finally, it is advantageous if machine learning is used to

[0018] Optimization of the operating parameters of the electrical energy supply modules is used. The optimization of fuel cell performance to the charge level of the respective battery can be continuously adjusted using AI. To do this, the AI ​​monitors how often the fuel cell needs to change its performance to keep the battery charge level within the permissible operating range and proactively changes the fuel cell specifications.

[0019] The object directed to an island network is achieved by an island network comprising electrical lines and a plurality of electrical units which can be coupled to the electrical lines and which can be electrical energy sources or electrical loads, wherein the electrical energy sources comprise a first electrical energy supply module and a second electrical energy supply module, in each of which energy can be provided both directly from a battery and via a DC / DC converter from a fuel cell, as well as jointly from the battery and fuel cell, wherein the electrical energy sources of the island network are configured in such a way that they each communicate data such as their respective actual values, reserves and minimum setpoints to the other electrical energy sources in the island network, wherein the electrical loads of the island network are each configured in such a way thatthat they communicate data such as their actual value and their achievable maximum value in the island grid, and wherein the electrical energy sources of the island grid are configured in such a way that they each calculate their own setpoint based on the data of the other electrical energy sources and the electrical loads and communicate this setpoint to the other electrical energy sources, wherein the first electrical energy supply module is configured in such a way that a charge state of its battery is determined and an operating point of its fuel cell or an operating point of its DC / DC converter is controlled depending on the charge state of the battery, wherein if a lower charge limit of the battery of the first electrical energy supply module is undershot, the power of the fuel cell of the first electrical energy supply module is increased,until the battery changes to the state of charge or until the fuel cell has reached an upper power limit, whereby, if this is not sufficient to charge the battery of the first electrical power supply module, the operating status of the first electrical power supply module is changed so that it is no longer available for the grid supply and the battery of the first electrical power supply module is charged to a predetermined state of charge, whereby in parallel the operating status of a second electrical power supply module is changed so that it is available for the grid supply in order to cover a requested grid load.

[0020] State-of-the-art power grids typically featured a central, highly redundant control unit that handled power management. If this unit failed, or if communication with it was interrupted, the grid was in "emergency mode," requiring manual control, or parts of it failed completely.

[0021] According to the invention, central control is eliminated, as the participating units each take over control using the same relevant algorithms and data known throughout the entire network. Multiple units can fail without significantly impairing the control functions in the island grid. Furthermore, prioritization and redundancies can be specified and are adaptable during operation.

[0022] A combination of various energy sources, storage devices, and consumers is also possible. This means that the composition of the networks, in terms of the type and number of individual modules, is freely configurable.

[0023] Particularly with regard to the use of batteries and fuel cells, the invention proposes a solution that takes into account the dynamics of fuel cells and their service life. Until now, batteries were always centrally assigned to individual power supplies. In the method according to the invention, the fuel cell and battery, along with their control systems, are combined and assigned to the grid as a unit. This allows power generation to be freely configured depending on the application profile, as well as grid redundancy.

[0024] The invention is explained in more detail by way of example with reference to the drawings. They show schematically and not to scale:

[0025] Figure 1 is a simplified representation of an electrical energy distribution network with several electrical energy sources and electrical consumers and

[0026] Figure 2 shows an energy supply module with battery and fuel cell.

[0027] Figure 1 shows a schematic and exemplary electrical island network 1 according to the invention. In this figure, the selected network topology is represented as a bus. It is important to note that other network topologies such as a ring, mesh network, tree, and other conceivable variants can also be successfully used. The versatility of the invention is revealed in the ability to use different network topologies to meet the specific requirements and conditions of the respective application environment.

[0028] The island network 1 in the exemplary embodiment of Figure 1 comprises electrical lines 2 and a plurality of electrical units 3 which can be coupled into the island network 1 via electrical lines 2 and by means of switches 11 and which can be electrical energy sources 4 or electrical loads 5 or consumers. In the exemplary embodiment of Figure 1, the island network 1 comprises as energy sources 4 a diesel generator 12, a steam turbine 13, a shaft generator 14, a first energy supply module 6 and a second energy supply module 7, which can be identical in construction to the first energy supply module 6. Figure 2 shows a schematic and exemplary first energy supply module 6. The first energy supply module

[0029] 6 comprises consumer connections 15, a battery 8 which is coupled directly to the consumer connections 15, a fuel cell 10 which is coupled to the consumer connections 15 via a DC / DC converter 9, and an energy management system 16 with which the operating point of the fuel cell 10 or the operating point of the DC / DC converter 9 can be controlled as a function of a charge state of the battery 8. The first electrical energy supply module 6 can supply energy to the island grid 1 in various ways. The energy can be provided either directly by its battery 8 or via its DC / DC converter 8 from its fuel cell 9 or jointly by the battery 8 and fuel cell 10.The internal control of the first energy supply module 6 takes place via a bus system 17, which ensures communication between the energy management system 16 and a battery management system 18, communication between the energy management system 16 and a fuel cell controller 19 and communication between the energy management system 16 and the DC / DC converter 9. All data necessary for the operation of the first electrical energy supply module 6, such as, for example, data from the current measurement at the consumer connections 15, control values, warnings and error messages, are transmitted via this bus system 17. The electrical energy supply module 6 operates independently and can be easily integrated into a network as required, for example with several electrical energy supply modules 6 connected in parallel that are independent of one another with regard to control.

[0030] 7 .

[0031] According to the invention, the first electrical energy supply module 6 is configured such that a charge state of its battery 8 is determined and an operating point of its fuel cell 9 or an operating point of its DC / DC converter 9 is controlled depending on the charge state of the battery 8. If a lower charge limit of the battery 8 of the first electrical energy supply module 6 is undershot, a power of the fuel cell 10 of the first electrical energy supply module 6 is increased until the battery 8 changes to the charge state or until the fuel cell 10 has reached an upper power limit.If this is not sufficient to charge the battery 8 of the first electrical energy supply module 6, the operating status of the first electrical energy supply module 6 is changed so that it is no longer available for the grid supply and the battery 8 of the first electrical energy supply module 6 is charged to a predetermined charge level, wherein in parallel the operating status of a second electrical energy supply module 7 is changed so that it is available for the grid supply in order to cover a requested grid load.

[0032] According to the invention, the electrical energy sources 4 of the island network 1 are configured such that they each communicate data such as their respective actual values, reserves and minimum setpoints to the other electrical energy sources 4 in the island network 1, wherein the electrical loads 5 of the island network 1 are each configured such that they communicate data such as their actual value and their achievable maximum value in the island network 1, and wherein the electrical energy sources 4 of the island network 1 are configured such that they each calculate their own setpoint on the basis of the data of the other electrical energy sources 4 and the electrical loads 5 and communicate this setpoint to the other electrical energy sources 4.

[0033] An island network 1 according to the present invention is in no way limited to the specific exemplary embodiment according to Figure 1. The invention encompasses a multitude of possible designs and variations that may deviate from the embodiment shown in Figure 1. The decentralized energy management of the island network 1 offers the possibility of easily integrating additional electrical energy sources 4 and electrical loads 5 into the system. This applies both to electrical units 3 of the same type and to different types of electrical units 3. The present invention enables a broad spectrum of applications and technical implementations. This flexibility makes it possible to create alternative topologies and arrangements that better meet the specific requirements and needs of the respective environment or application.

Claims

Patent claims 1. A method for supplying energy in an island network (1), the island network (1) comprising electrical lines (2) and a plurality of electrical units (3) which can be coupled to the electrical lines (2), which are electrical energy sources (4) or electrical loads (5), wherein the electrical energy sources (4) comprise a first electrical energy supply module (6) and a second electrical energy supply module (7), in each of which energy is provided both directly by a battery (8) and via a DC / DC converter (9) from a fuel cell (9), as well as jointly by the battery (8) and the fuel cell (10), wherein the electrical energy sources (4) of the island network (1) each communicate data such as their respective actual values, reserves and minimum setpoint values ​​to the other electrical energy sources (4) in the island network (1),wherein the electrical loads (5) of the island grid (1) communicate data such as their actual value and their achievable maximum value in the island grid (1), and wherein the electrical energy sources (4) of the island grid (1) each calculate their own setpoint based on the data of the remaining electrical energy sources (4) and the electrical loads (5) and communicate this setpoint to the remaining electrical energy sources (4), wherein a charge state of the battery (8) of the first electrical energy supply module (6) is determined, and an operating point of its fuel cell (10) or an operating point of its DC / DC converter (9) is controlled depending on the charge state of its battery (8), wherein if the charge falls below a lower limit of the battery (8) of the first electrical energy supply module (6), the power of the fuel cell (10) of the first electrical energy supply module (6) is increased,until the battery (8) of the first electrical energy supply module (6) changes to the charging state or until the fuel cell, (10) of the first electrical energy supply module (6) has reached an upper power limit, characterized in that, if this is not sufficient to charge the battery (8) of the first electrical energy supply module (6), the operating status of the first electrical energy supply module (6) is changed so that it is no longer available for the mains supply and the battery (8) of the first energy supply module (6) is charged to a predetermined charge level, wherein in parallel the operating status of the second electrical energy supply module (7) is changed so that it is available for the mains supply in order to cover a requested network load.

2. The method according to claim 1, wherein upon reaching an upper charge limit of the battery (8) of the first electrical energy supply module (6), the operating status of the first electrical energy supply module (6) is set such that it is again available for the mains supply.

3. Method according to one of the preceding claims, wherein data of an electrical unit (3) are communicated to the other electrical units (3) in a time-controlled manner and in cycles, and the electrical units (3) of the island network (1) are controlled on the basis of the data and by means of an algorithm available to the electrical units (3).

4. Method according to one of the preceding claims, wherein a prioritization of the electrical units (3) is dynamically adjusted.

5. The method according to claim 4, wherein the method relates to the energy supply on a ship and the prioritization is specified by selecting a driving profile.

6. The method according to claim 4, wherein the prioritization is defined by means of a priority list.

7. The method according to claim 4, wherein the prioritization is adjusted based on an operating hour evaluation of the electrical units (3).

8. Method according to one of the preceding claims, wherein a redundancy requirement is defined and, when a predetermined limit is undershot in the island network (1), the operating status of at least one unused electrical energy source (4) is changed so that it is available for the grid supply in order to cover a requested redundancy.

9. Method according to one of the preceding claims, wherein machine learning is used to optimize the operating parameters of the electrical energy supply modules (6, 7).

10. An island network (1) comprising electrical lines (2) and a plurality of electrical units (3) which can be coupled to the electrical lines (2), which units can be electrical energy sources (4) or electrical loads (5), wherein the electrical energy sources (4) comprise a first electrical energy supply module (6) and a second electrical energy supply module (7), in each of which energy can be provided both directly by a battery (8) and via a DC / DC converter (8) from a fuel cell (9), as well as jointly by the battery (8) and the fuel cell (10), wherein the electrical energy sources (4) of the island network (1) are configured in such a way that they each communicate data such as their respective actual values, reserves and minimum setpoint values ​​to the other electrical energy sources (4) in the island network (1), wherein the electrical loads (5) of the island network (1) are each configured in such a way that they each communicate data such as their actual value and their achievable maximum malwert in the island network (1) and wherein the electrical energy sources (4) of the island network (1) are configured in such a way that they each calculate their own setpoint on the basis of the data of the other electrical energy sources (4) and the electrical loads (5) and communicate this setpoint to the other electrical energy sources (4), wherein the first electrical energy supply module (6) is configured in such a way that a charge state of its battery (8) is determined and an operating point of its fuel cell (9) or an operating point of its DC / DC converter (9) is controlled depending on the charge state of the battery (8), wherein, when the charge level of the battery (8) of the first electrical energy supply module (6) falls below a lower charge limit, the power of the fuel cell (10) of the first electrical energy supply module (6) is increased until the battery (8) changes to the charge state or until the fuel cell (10) has reached an upper power limit, characterized in that, if this is not sufficient to charge the battery (8) of the first electrical energy supply module (6), the operating status of the first electrical energy supply module (6) is changed so that it is no longer available for the mains supply and the battery (8) of the first electrical energy supply module (6) is charged to a predetermined charge state, wherein, in parallel, the operating status of a second electrical energy supply module (7) is changed,so that it is available for grid supply to cover a requested grid load.

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