Fuel cell device, and method for fuel cell device
The fuel cell facility incorporates an electrical power resistor network to convert surplus energy into waste heat during network failures, addressing the risk of damage from sudden load changes and ensuring system stability.
Patent Information
- Application Number
- JP2024564681
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-13
- Filing Date
- 2023-06-12
- Publication Date
- 2025-06-26
AI Technical Summary
Fuel cell facilities face damage due to sudden load changes or network failures, which can lead to unacceptable heating and potential complete damage, especially when combustion gas energy is not converted into electrical energy.
A fuel cell facility with an electrical power resistor network that maintains the load point of the fuel cell stacks during network failures by converting surplus electrical energy into waste heat, thereby preventing damage and ensuring system stability.
The solution effectively prevents damage to the fuel cell facility by maintaining the load point during network failures, ensuring the fuel cell stacks operate within safe power dynamics and reducing the risk of overheating.
Smart Images
Figure 2025519329000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to fuel cell equipment, and more particularly to a method for protecting the load point of a fuel cell stack of a fuel cell system in a fuel cell equipment when a failure, particularly a network failure of an electrical output network system, occurs.
Background Art
[0002] From the prior art, a usage method is known in which electrical energy generated by a SOFC fuel cell stack (the abbreviation SOFC represents "Solid Oxide Fuel Cell" in English and a solid oxide type fuel cell in German) is supplied to an AC three-phase current network.
[0003] The power dynamics of such a fuel cell stack are low. There are multiple reasons for this, for example, due to a sudden temperature gradient that may occur during a load jump, there is a risk of crack formation in the battery. Therefore, such a fuel cell stack cannot follow rapid electrical load changes.
[0004] In addition to the fuel cell stack itself, the entire fuel cell system may also be damaged by a sudden load drop. The combustion gas is not converted into electrical energy in this case, which may lead to unacceptable heating in, for example, the oxidation catalyst of the fuel cell system, and in the worst case, to complete damage.
[0005] The risk that combustion gas energy is not converted into electrical energy also occurs in the case of a supply network outage. Regionally, and according to the so-called "grid code", the requirements regarding network stability that are stipulated also require a special electrical design for such a situation (for example, the so-called low voltage ride through).
[0006] Yet another fuel cell facility and a method for maintaining the load point of a fuel cell stack in a fuel cell system of such a fuel cell facility are known from German Patent Application Publication No. 102013207349, European Patent No. 1968142, German Patent Application Publication No. 10106219, European Patent Application Publication No. 3333951, and German Patent Application Publication No. 102019111462.
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0007] The problem of the present invention is to provide a fuel cell facility having a simple and low-cost electrical design optimized so that a failure, particularly a network failure, particularly a network outage, does not result in damage to the fuel cell facility.
MEANS FOR SOLVING THE PROBLEM
[0008] The above problems are solved by a fuel cell facility having the constituent elements of claim 1 and a method having the constituent elements of claim 10. Other constituent elements and details of the present invention will become apparent from the dependent claims, the detailed description of the invention, and the drawings. At this time, the constituent elements and details described in connection with the fuel cell according to the present invention naturally also apply in connection with the method according to the present invention, and vice versa. Therefore, mutual reference is always made or can be made regarding the disclosure of each inventive aspect.
[0009] According to the present invention, a fuel cell facility having a fuel cell system is contemplated. The fuel cell system includes a plurality of fuel cell stacks, and the fuel cell system is connected to, or connectable to, an electrical output network system including an electrical output network for supplying electrical energy generated by the operation of the fuel cell stacks to the electrical output network. The fuel cell facility further includes an electrical power resistor network including an electrical power resistor for maintaining the load point of the fuel cell stacks when a failure occurs, particularly a network failure of the electrical output network system, and the fuel cell system is connected to the electrical power resistor network for supplying electrical energy generated by the operation of the fuel cell stacks to the electrical power resistor network.
[0010] Accordingly, the present invention provides a network outage fuel cell facility in which, when a failure occurs, particularly a network failure, particularly a network outage, the fuel cell stack does not have to move away from its operating point or load point. At least the fuel cell stack does not have to change the load point beyond a pre-set level based on power dynamics that can be considered harmless with respect to the risk of possible damage to the fuel cell system. At this time, the network failure is characterized in that only a reduced amount of electrical energy can flow into the electrical output network, or in particular, in the case of a network outage, electrical energy cannot flow. Such a network outage can occur, for example, when a short circuit occurs outside the fuel cell facility. The electrical energy generated by the fuel cell stack is normally released into the electrical output network during normal operation, so this is called the output network. Alternatively, this can also be called the supply network. That is, due to a network failure, when the generated power cannot be released into the electrical output network, particularly an AC and / or three-phase current network, the surplus energy can be supplied to an electrical power resistor. When the network failure is resolved, the network voltage returns to its original value and the electrical energy can flow back into the electrical output network instead of the electrical power resistor.
[0011] The fuel cell facility according to the present invention relates in particular to the preservation of the load point of the fuel cell stack of the fuel cell system of the fuel cell facility when a network failure of the electrical output network occurs, but can also be preferably applied for load point preservation in the case of a non-network-constrained system. Accordingly, all the components described in connection with the occurrence of a network failure are also applicable in the case of a non-network-constrained system.
[0012] The fuel cell stack is very preferably a solid oxide fuel cell stack. Accordingly, the fuel cell system may in particular be a solid oxide fuel cell system or a solid oxide electrolytic cell system (SOFC system representing "Solid Oxide Fuel Cell System" in English). Furthermore, the individual fuel cell stacks may be electrically connected in parallel to each other, in particular via an electrical (voltage) intermediate circuit which will be described in detail later. Alternatively, it is also possible to electrically connect the individual or all of the fuel cell stacks in series with each other.
[0013] The electrical power resistor is preferably set up to convert electrical energy into waste heat. For example, surplus electrical energy that cannot be released from the fuel cell facility via the electrical output network in the event of a network failure can be removed from the fuel cell facility in a preferred manner, namely as waste heat. Accordingly, waste heat in particular means that heat converted from electrical energy to thermal energy is released. It is very preferable that the waste heat is released to the outside of the fuel cell stack and the fuel cell system. That is, preferably, the waste heat is not supplied to the fuel cell stack, for example, such a supply would increase the efficiency but is not suitable for the purpose. This is because in that case, even more electrical energy would have to be converted into waste heat.
[0014] Furthermore, the electrical power resistor is preferably arranged outside the fuel cell stack. As described above, this is preferable in order not to utilize the heat generated by the electrical power resistor inside the fuel cell stack. Instead, the external design space of the fuel cell system having the fuel cell stack can be utilized for the electrical power resistor network. An optional cooling section can be arranged and designed well technically in the design space.
[0015] Furthermore, for example, the fuel cell facility preferably includes a cooling unit for cooling an electrical power resistor. The cooling unit may be an air-cooled and / or water-cooled cooling unit, that is, it may be set up for cooling by air, particularly by ambient air, and / or for cooling by water. Within the framework of the present invention, water is preferably understood to be any coolant that is particularly in a liquid state. Air can be circulated, for example, by a fan. Water can be actively cooled by a cooling assembly. Thereby, a particularly large amount of electrical energy can be dissipated by the electrical power resistor without it being damaged, which is particularly preferable in the case of a network outage where no electrical energy can be dissipated via the electrical output network. In principle, cooling may preferably be carried out by natural convection in some cases.
[0016] Furthermore, the electrical power resistor network preferably includes power electronics set up to activate the electrical power resistor when a network fault occurs. The activation of the electrical power resistor here means that the electrical energy generated by the fuel cell system is supplied to the electrical power resistor, whereby it dissipates electrical energy, particularly converting it into waste heat, or, in other words, converting it into thermal energy and dissipating it.
[0017] At this time, it is highly preferable that the power electronics continuously measure the voltage of the electrical intermediate circuit between the fuel cell system and the electrical output network system and are set up to activate the electrical power resistor when a voltage increase occurs in the electrical intermediate circuit. The electrical intermediate circuit may in particular be a DC intermediate circuit. For example, the power electronics can very quickly determine a fault with reference to the voltage measurement and any occurring voltage increase. Thus, in order to avoid damage to the fuel cell installation, the electrical power resistor can be activated with a minimum time delay in the event of a fault. At this time, the voltage increase required for activation of the power electronics may in particular be pre-defined. At this time, the voltage increase may in particular be pre-defined as an absolute maximum voltage value and / or as a voltage change in a predetermined time period. Thus, the electrical power resistor can in particular be activated when the actual voltage measured continuously exceeds the pre-defined maximum absolute voltage value or when it undergoes a predetermined voltage change in a predetermined time period.
[0018] Furthermore, it is preferable that the power electronics have a controller for controlling the electrical energy supplied to the electrical power resistor depending on the voltage measured in the electrical intermediate circuit. In that way, the electrical energy can be dissipated by the electrical power resistor only within the range required by the degree of the fault, in particular when a total stop or network stop has not occurred. It can also be easily determined that the fault has been resolved and that the electrical output network system is available again.
[0019] The fuel cell system preferably maintains the operating point when a network failure occurs. However, the fuel cell system may also be set up to lower the load point of the operating fuel cell stack when a failure, particularly a network failure, occurs. In other words, the operating point of the fuel cell stack can be decreased when a failure, particularly a network failure, occurs. This enables the electrical energy generated by the fuel cell stack to be reduced in the fuel cell facility, relieving the electrical power resistor of load and reducing the resource consumption in the fuel cell stack. Also in this case, the controller described above or other controllers can be used to control the load point of the fuel cell stack, particularly depending on the voltage measured by the power electronics. At this time, the power dynamics of the fuel cell stack can be considered, thereby preventing the fuel cell stack from being lowered beyond its power dynamics with respect to its load point and avoiding damage to the fuel cell stack. Power dynamics represent how fast the fuel cell stack can be lowered without damage with respect to its load. That is, power dynamics are an operating setting and can be represented, for example, by the current change rate.
[0020] Furthermore, an electrical power resistor network is arranged in an electrical intermediate circuit between the DC / DC converter of the fuel cell stack and the DC / AC converter of the electrical output network system. The DC / AC converter is configured bidirectionally and connected to the electrical output network, so that electrical energy can be released from the electrical intermediate circuit to the electrical output network and supplied from the electrical output network to the electrical intermediate circuit.
[0021] In that sense, the voltage measurement described above can be performed in this electrical intermediate circuit, particularly in a DC intermediate circuit. At this time, the voltage in the electrical intermediate circuit is preferably controlled to a constant voltage by the electrical output network system. That is, at least one DC / AC converter preferably has an operating mode of maintaining a constant voltage in the electrical intermediate circuit. At this time, the electrical power resistor network, the DC / DC converter of the fuel cell stack, and the DC / AC converter may be arranged in parallel with each other. At this time, it is possible to attach one DC / DC converter to each fuel cell stack, or in other words, to be electrically connected thereto. It is also possible to provide a plurality of electrical output networks, and each electrical output network can have a DC / AC converter. The DC / AC converter is intended to have bidirectional functionality. In principle, two DC / AC converters connected in series may be provided, and these may have unidirectional functionality, but it is also possible to operate in opposite directions to each other. In this way, electrical energy can also be drawn from the electrical output network as necessary, which is particularly for supplying the electrical facility peripheral equipment network during the warm-up and cooling stages of the fuel cell stack for the operation of the fuel cell facility.
[0022] Furthermore, the fuel cell facility preferably includes an electrical balance-of-plant network including equipment peripheral devices for supporting the operation of the fuel cell system. The fuel cell system is connected to the electrical balance-of-plant network to supply the electrical energy generated by the operation of the fuel cell stack to the electrical balance-of-plant network. At this time, the electrical balance-of-plant network may also be connected to an electrical intermediate circuit, and in particular, may be connected in parallel with an electrical power resistor network, a fuel cell system, and an electrical output network system. The equipment peripheral devices are also called "Balance of Plant" in English. In particular, the equipment peripheral devices can include a plurality of or all components of the fuel cell system except for the fuel cell stack itself. Such components include, for example, pumps, sensors, heat exchangers, seals, compressors, recirculation fans, charge air coolers, humidifiers, and the like. These receive a supply of electrical energy for operation by the balance-of-plant network, whereby these components can utilize the proper operation of the fuel cell stack for the generation of electrical energy. Accordingly, the bi-directionality of the DC / AC converter in the electrical output network system described above is preferable when starting and stopping the fuel cell stack, or in other words, during warming up and cooling. This is because the fuel cell stack itself typically does not generate electrical energy at this time, or does not generate enough to reliably supply electrical energy to the equipment peripheral devices. It is possible to optionally provide an electrical accumulator, but this results in a cost-intensive investment due to the high capacitance required.
[0023] A method for protecting the load point of the fuel cell stack of the fuel cell system of the fuel cell facility according to the present invention when a failure occurs in the electrical output network system that receives the supply of electrical energy generated by the operation of the fuel cell stack, particularly a network failure, is also an object of the present invention. This method has the following steps: - The occurrence of a failure, particularly a network failure in the electrical output network system, - It is determined that a failure has occurred, particularly a network failure, and - Between the fuel cell system and the electrical output network system, electrical energy in the fuel cell facility is converted into waste heat by an electrical power resistor.
[0024] Accordingly, the method according to the invention provides the same advantages as detailed in connection with the fuel cell facility according to the invention.
[0025] In particular, the fuel cell facility according to the invention may be set up or configured to carry out the method according to the invention. Conversely, the method according to the invention can in particular be carried out by or within the fuel cell facility according to the invention.
[0026] The failure that occurs, particularly a network failure, is preferably determined by measuring the voltage rise in the electrical intermediate circuit between the fuel cell system and the electrical output network system.
[0027] More preferably, the electrical energy converted by the electrical power resistor is controlled depending on the voltage measured in the electrical intermediate circuit.
[0028] Finally, the operating point of the fuel cell stack can preferably be reduced within the power dynamics available on the side of the fuel cell stack after a failure, particularly a network failure, has been determined. If the power resistor is designed to be sufficiently large, it may be preferable for the operating point to remain unchanged.
[0029] Other advantages, components, and specific details of the invention will become apparent from the following description, which details embodiments of the invention with reference to the drawings. The drawings schematically show the following:
Brief Description of the Drawings
[0030]
Figure 1
Figure 2
Figure 3
Figure 4
Mode for Carrying Out the Invention
[0031] The same members or functions are given the same reference numerals in FIGS. 1 to 4, respectively.
[0032] FIG. 1 shows a circuit diagram of a fuel cell facility 1 based on one embodiment of the present invention. This fuel cell facility 1 includes a number of fuel cell stacks 10 each electrically connected in parallel to an electrical intermediate circuit 40. As an alternative to the fuel cell facility 1 of FIG. 1, as shown in FIG. 4, the fuel cell stacks 10 may alternatively be connected in series with each other.
[0033] In addition to the fuel cell stacks 10, an electrical output network system 20, an electrical facility peripheral device network 30, and an electrical power resistor network 50 are each wired to each other and to the fuel cell stacks 10 in parallel by an electrical intermediate circuit 40.
[0034] FIG. 2 shows a part of the fuel cell facility 1 of FIG. 1 indicated by the symbol A in FIG. 1. This fuel cell facility here includes, by way of example, 10 fuel cell stacks 10, but alternatively, there may be more or fewer fuel cell stacks 10. Accordingly, FIG. 2 shows in detail only 3 fuel cell stacks 10 by way of example, and the other fuel cell stacks 10 in FIG. 1 are not shown here or may be omitted as an alternative.
[0035] The fuel cell stack 10 is part of a fuel cell system 12 that further includes a DC / DC converter 14, with one DC / DC converter 14 attached to each fuel cell stack 10. Each of the DC / DC converters 14 electrically connects each fuel cell stack 10 to an electrical intermediate circuit 40 so as to form a DC intermediate circuit in this example (DC means "Direct Current" and in German means direct current or DC voltage).
[0036] Furthermore, the electrical output network system 20 has a DC / AC converter 22 connected to an electrical output network 24. The DC / AC converter 22 is configured as a bidirectional DC / AC converter 22 (AC means "Alternating Current" and in German means alternating current or AC voltage). Thereby, depending on the operating direction of the DC / AC converter 22, electrical energy, or in other words current, can be discharged from the electrical intermediate circuit 40 to the electrical output network 24, or supplied from the electrical output network 24 to the electrical intermediate circuit 40.
[0037] Furthermore, the electrical peripheral equipment network 30 has peripheral equipment 34 such as pumps, sensors, heat exchangers, seals, compressors, recirculation fans, charge air coolers, and / or humidifiers, etc. for supporting the operation of the fuel cell system 12. The peripheral equipment 34 is connected to the electrical intermediate circuit 40 via a converter 32. The converter 32 is manufactured here as a DC / AC converter, but alternatively it may be manufactured as a DC / DC converter.
[0038] The electrical power resistor network 50 has an electrical power resistor 52 and power electronics 54 electrically connected to an electrical intermediate circuit 40. Furthermore, the power electronics 54 can have various components, in particular a voltage measuring device for measuring the voltage in the electrical intermediate circuit 40 and / or a controller for controlling the electrical energy supplied from the electrical intermediate circuit 40 to the electrical power resistor 52, etc.
[0039] FIG. 3 shows the progress of a method 100 according to one embodiment of the present invention illustrated by way of example using the fuel cell system - power transition 120 in kW units with respect to time of the fuel cell system 12 and the facility peripheral equipment network - power transition in kW units with respect to time of the facility peripheral equipment network 30.
[0040] Here, in the first step 102 of the method, the fuel cell system 12 operates at full output and supplies, by way of example, 60 kW here (see the fuel cell system - power transition 120 in the time domain of the first step 102). At this time, a part of this power of the fuel cell system 12 is provided to the electrical facility peripheral equipment network 30 as can be seen by referring to the facility peripheral equipment network - power transition 130.
[0041] Here, as the second step of the method 100, it is assumed that a network fault 104 in the electrical output network 24, in particular a network shutdown, occurs, whereby the electrical output network 24 can no longer receive electrical energy from the electrical intermediate circuit 40. The occurrence of such a network fault 104 can preferably be determined by the power electronics 54 that determines a voltage in the electrical intermediate circuit 40 by means of a voltage measuring device that exceeds a predefined maximum voltage for the network fault 104, whereby the network fault 104 is determined.
[0042] Subsequently, in the third step 106 of method 100, the electrical power resistor 52 is activated by the power electronics 54. Subsequently, the electrical energy in the electrical intermediate circuit 40, which is generated by the fuel cell system 12 and supplied to the electrical intermediate circuit 40, is supplied to the electrical power resistor 52, which converts the electrical energy into waste heat. This conversion takes place outside the fuel cell system 12. The electrical power resistor 52 is preferably cooled during operation, and particularly preferably water-cooled.
[0043] In parallel with or subsequent to the third step 106, the fourth step 108 of method 100 is initiated to reduce the load point of the operating fuel cell stack 10 within the power dynamics available on the side of the fuel cell stack 10 after the determination of the network fault 104. Thereby, as can be seen by referring to the time region of the third step 106 of the fuel cell system - power transition 120, the electrical energy generated thereby decreases over time. That is, it is only necessary to release less electrical energy from the electrical intermediate circuit 40 to the electrical power resistor 52.
[0044] When the network fault 104 is resolved, at a specific point in time, the network restoration 110 of the electrical output network 24 is performed as the fifth step of method 100. Then, the electrical output network 24 can be reused for the supply of electrical energy from the electrical intermediate circuit 40.
[0045] Accordingly, in the sixth step 112 of method 100, electrical energy is supplied again to the electrical output network 24 instead of to the electrical power resistor 52. In that sense, the electrical power resistor 52 is switched off by the power electronics 54. At this time, the determination of network return 110 can also be performed by voltage measurement on the side of the power electronics 54. In parallel with or subsequent to the sixth step 112, the seventh step 114 of method 100 is executed, and the operating point of the fuel cell stack 10 in operation is raised again within the power dynamics available on the side of the fuel cell stack 10 after the determination of network return 110.
[0046] FIG. 4 shows an alternative embodiment of the fuel cell installation 1 in which the fuel cell stacks 10 of the fuel cell system 12 are wired in series with each other as an example. In addition to this, a common DC / AC converter 22 is used for the electrical output network 24 and the installation peripheral equipment 34.
[0047] However, in particular, the electrical power resistor 52 is arranged not in the electrical intermediate circuit 40 but between the DC connection of the fuel cell stack 10 and the DC / AC converter 22. The power electronics 54 responsible for the control and / or regulation of the electrical power resistor 52 is preferably a part of the DC / AC converter 22 here.
[0048] That is, the electrical power resistor 52 can be connected directly to the DC connection of the fuel cell stack 10 or to the electrical intermediate circuit 40 as shown in FIGS. 1 and 2. The control circuit for the control can be implemented in a separate control unit having a transistor switch for the electrical power resistor or in a central control device.
[0049] The above description of each embodiment has described the present invention only within the framework of examples. (Other possible items) (Item 1) A fuel cell facility (1) for a fuel cell system (12) including a plurality of fuel cell stacks (10), wherein the fuel cell system (12) is connected to or connectable to an electrical output network system (20) including the electrical output network (24) for supplying electrical energy generated by the operation of the fuel cell stack (10) to the electrical output network (24). In the fuel cell facility, the fuel cell facility (1) further includes an electrical power resistor network (50) including an electrical power resistor (52) for maintaining the load point of the fuel cell stack (10) when a failure, particularly a network failure (104) of the electrical output network system (20), occurs. The fuel cell system (12) is connected to the electrical power resistor network (50) for supplying electrical energy generated by the operation of the fuel cell stack (10) to the electrical power resistor network (50). (Item 2) The fuel cell facility (1) according to item 1, wherein the electrical power resistor (52) is set up to convert electrical energy into waste heat. (Item 3) The fuel cell facility (1) according to item 1 or 2, wherein the electrical power resistor (52) is arranged outside the fuel cell stack (12). (Item 4) The fuel cell facility (1) according to any one of the preceding items, wherein the fuel cell facility (1) includes a cooling unit for cooling the electrical power resistor (52). (Item 5) The fuel cell facility (1) according to any one of the preceding items, wherein the electrical power resistor network (50) includes power electronics (54) set up to activate the electrical power resistor (52) when a network failure (104) occurs. (Item 6) The power electronics (54) is set up to continuously measure the voltage of an electrical intermediate circuit (40) between the fuel cell system (12) and the electrical output network system (20), and to activate the electrical power resistor (52) when a voltage increase occurs in the electrical intermediate circuit (40). The fuel cell facility (1) according to item 5. (Item 7) The power electronics (54) has a controller for controlling the electrical energy supplied to the electrical power resistor (52) depending on the voltage measured in the electrical intermediate circuit (40). The fuel cell facility (1) according to item 6. (Item 8) The fuel cell system (12) is set up to reduce the load point of the fuel cell stack (10) in operation when a failure occurs. The fuel cell facility (1) according to any one of the preceding items. (Item 9) The electrical power resistor network (50) is arranged in an electrical intermediate circuit (40) between the DC / DC converter (16) of the fuel cell stack (10) and the DC / AC converter (22) of the electrical output network system (20). The fuel cell facility (1) according to any one of the preceding items. (Item 10) The electrical power resistor network (50) is arranged between the DC connection of the fuel cell stack (10) and the DC / AC converter (22) of the electrical output network (24). The fuel cell facility (1) according to any one of items 1 to 8. (Item 11) The fuel cell equipment (1) includes an electrical peripheral equipment network (30) including peripheral equipment (34) for the operation of the fuel cell system (12), and the fuel cell system (12) is connected to the electrical peripheral equipment network (30) to supply electrical energy generated by the operation of the fuel cell stack (10) to the electrical peripheral equipment network (30). The fuel cell equipment (1) according to any one of the preceding items. (Item 12) In a method (100) for load point protection of the fuel cell stack (10) of the fuel cell system (12) of the fuel cell equipment (1) when a failure occurs in the electrical output network system (20) that receives the supply of electrical energy generated by the operation of the fuel cell stack (10), the method (100) includes the following steps: - A failure occurs, particularly a network failure (104) of the electrical output network system (20). - The occurred failure, particularly the network failure (104), is determined, and - Electrical energy is converted into waste heat by an electrical power resistor (52) in the fuel cell equipment (1) between the fuel cell system (12) and the electrical output network system (20). The method is characterized by having the above. (Item 13) The method (100) according to item 12, wherein the failure that occurs, particularly the network failure (104), is determined by measuring the voltage rise in the electrical intermediate circuit (40) between the fuel cell system (12) and the electrical output network system (20). (Item 14) The method (100) according to item 13, wherein the electrical energy converted by the electrical power resistor (52) is controlled depending on the voltage measured in the electrical intermediate circuit (40). (Item 15) The load point of the fuel cell stack (10) during operation is reduced within the framework of the power dynamics available on the side of the fuel cell stack (10) after a fault, in particular a network fault (104), has been determined, according to the method (100) according to any one of claims 12 to 14.
Explanation of Signs
[0050] 1 Fuel cell facility 10 Fuel cell stack 12 Fuel cell system 14 DC / DC converter 20 Electrical output network system 22 (DC / AC converter of the electrical output network system) 24 Electrical output network 30 Electrical equipment peripheral network 32 (Converter of the electrical equipment peripheral network) 34 Equipment peripheral equipment 40 Electrical intermediate circuit 50 Electrical power resistor network 52 Electrical power resistor 54 Power electronics 100 Method 102 First step 104 Network fault 106 Third step 108 Fourth step 110 Network recovery 112 Sixth step 114 Seventh step 120 Fuel cell system - power transition 130 Equipment peripheral network - power transition
Claims
1. A fuel cell facility for a fuel cell system including a plurality of fuel cell stacks, wherein the fuel cell system is connected to, or connectable to, an electrical output network system including the electrical output network for supplying electrical energy generated by the operation of the fuel cell stacks to the electrical output network, and the fuel cell facility further includes an electrical power resistor network including an electrical power resistor for maintaining the load point of the fuel cell stacks when a failure, particularly a network failure of the electrical output network system, occurs, and the fuel cell system is connected to the electrical power resistor network for supplying electrical energy generated by the operation of the fuel cell stacks to the electrical power resistor network. In the fuel cell facility, the electrical power resistor network is arranged in an electrical intermediate circuit between a DC / DC converter of the fuel cell stack and a DC / AC converter of the electrical output network system, and the DC / AC converter is configured bidirectionally and connected to the electrical output network, whereby electrical energy can be discharged from the electrical intermediate circuit to the electrical output network and supplied from the electrical output network to the electrical intermediate circuit.
2. The fuel cell facility according to claim 1, wherein the electrical power resistor is set up to convert electrical energy into waste heat.
3. The fuel cell facility according to claim 1, wherein the electrical power resistor is arranged outside the fuel cell stack.
4. The fuel cell facility according to claim 1, wherein the fuel cell facility includes a cooling unit for cooling the electrical power resistor.
5. The fuel cell facility according to claim 1, wherein the electrical power resistor network includes power electronics set up to activate the electrical power resistor when a network failure occurs.
6. The power electronics is set up to continuously measure the voltage of an electrical intermediate circuit between the fuel cell system and the electrical output network system, and to activate the electrical power resistor when a voltage increase occurs in the electrical intermediate circuit. The fuel cell facility according to claim 5.
7. The power electronics has a controller for controlling the electrical energy supplied to the electrical power resistor depending on the voltage measured in the electrical intermediate circuit. The fuel cell facility according to claim 6.
8. The fuel cell system is set up to lower the load point of the operating fuel cell stack when a failure occurs. The fuel cell facility according to claim 1.
9. The fuel cell facility includes an electrical peripheral equipment network including equipment peripheral equipment for supporting the operation of the fuel cell system. The fuel cell system is connected to the electrical peripheral equipment network to supply electrical energy generated by the operation of the fuel cell stack to the electrical peripheral equipment network. The fuel cell facility according to claim 1.
10. When a failure occurs in the electrical output network system that receives the electrical energy generated by the operation of the fuel cell stack, in the method for maintaining the load point of the fuel cell stack of the fuel cell system of the fuel cell facility according to any one of claims 1 to 9, the method includes the following steps: - A failure occurs, in particular a network failure in the electrical output network system. - The occurring failure is determined, in particular the network failure. And, - Electrical energy is converted into waste heat by an electrical power resistor in the fuel cell facility between the fuel cell system and the electrical output network system. The method has.
11. The occurring failure, in particular the network failure, is determined by measuring the voltage increase in the electrical intermediate circuit between the fuel cell system and the electrical output network system. The method according to claim 10.
12. The electrical energy converted by the electrical power resistor is controlled depending on the voltage measured in the electrical intermediate circuit. The method according to claim 11.
13. The load point of the fuel cell stack during operation is reduced within the framework of the power dynamics available on the side of the fuel cell stack after a fault, in particular a network fault, has been determined, according to the method of claim 10.