AU2018401946B2

AU2018401946B2 - Water-borne vehicle having a power supply unit

Info

Publication number: AU2018401946B2
Application number: AU2018401946A
Authority: AU
Inventors: Michael Braunecker; Ottmar Voitlein
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2018-01-12
Filing date: 2018-12-20
Publication date: 2021-06-24
Anticipated expiration: 2038-12-20
Also published as: KR20200105715A; EP3685484A1; WO2019137787A1; AU2018401946A1; DE102018200485A1

Abstract

The invention relates to a water-borne vehicle comprising a power supply unit (24), said power supply unit (24) comprising fuel cell modules (1) and DC-to-DC converters (16). The DC-to-DC converters (16) are electrically connected, in series, to a DC bus (25). The DC-to-DC converters (16) have a galvanic isolation (18). The DC-to-DC converters (16) supply electricity, in series, to a DC bus (25).

Description

Water-borne vehicle having a power supply unit

The invention relates to a water-borne vehicle having a power supply unit, wherein the power supply unit has fuel cell modules, a power supply unit for a water-borne vehicle, a method for operating a power supply unit of a water-borne vehicle, or a method for operating a water-borne vehicle having a power supply unit.

A water-borne vehicle is a submarine or a ship, for example. The ship is a cruise ship, a container ship, a ferry, a fishing boat, a speedboat, a cruiser, etc., for example. The use of fuel cells in a submarine is known from DE 10 2004 004 624 B3, for example. Fuel cells are also known from WO 03/030291 A2, for example.

The use of fuel cells in connection with a DC-to-DC converter (DC/DC converter) is known from DE 10 2010 041625 Al and also from DE 10 2013 209 396 Al.

Fuel cell modules for supplying power to a submarine are known from WO 2005/073075 Al. Fuel cells make it possible to generate electrical power in maritime applications in an environmentally friendly and silent manner. This relates not only to submarines (e.g. also unnamed submarine vehicles) but also to ships.

Aspects of the present disclosure improve operational reliability or availability of a power supply for a ship and/or a submarine.

According to an aspect of the present invention, there is provided a water-borne vehicle having a power supply unit, wherein the power supply unit comprises fuel cell modules and DC-to-DC converters such that each fuel cell module is connected to one of the DC-to-DC converters, wherein the DC-to-DC converters are electrically connected in series to provide electrical power to a DC voltage bus, wherein each of the DC-to-DC converters and the corresponding fuel cell module are configured to be bypassed, wherein, when being bypassed, each fuel cell module is configured to be removable while one or more of the remaining fuel cell modules continue to provide the electrical power to the DC voltage bus, and wherein, when a fuel cell module is removed, the removed fuel cell module is replaced with another fuel cell module.

la

According to another aspect of the present invention, there is provided a method for operating a power supply unit of a water-borne vehicle, wherein the power supply unit comprises fuel cell modules such that each fuel cell module is connected to one of the DC-to-DC converters, wherein the DC-to-DC converters are electrically connected in series to provide electrical power to a DC voltage bus, the method comprising: bypassing one of the DC-to-DC converters and the corresponding the fuel cell module; removing the bypassed fuel cell module, while one or more of the remaining fuel cell modules continue to provide the electrical power to the DC voltage bus; and replacing the removed fuel cell module with another fuel cell module.

A water-borne vehicle has a power supply unit. The power supply unit has fuel cell modules and DC-to-DC converters, wherein the DC-to-DC converters are electrically connected in series to a DC voltage bus. A modular design arises therefrom, through which modular design a high level of operational reliability can be achieved. The serial connection of the DC-to-DC converters is a series connection. In addition to fuel cells, the power supply unit can also have rechargeable batteries and/or diesel generators. In particular, an electric motor is provided for driving the water-borne vehicle. The DC voltage bus is in particular a power bus for supplying the water-borne vehicle with electrical power.

If the DC-to-DC converters are electrically connected in series to a DC voltage bus, said DC voltage bus can thus be completely or partially powered by said DC-to-DC converters. Owing to the serial electrical connection of the DC-to-DC converters, each of these serially connected DC-to-DC converters can contribute its voltage swing component.

In one configuration of the water-borne vehicle or the power supply unit, the DC-to-DC converters can be disconnected from the DC voltage bus via switches.

In one configuration of the water-borne vehicle or the power supply unit, the DC-to-DC converters can be disconnected from the DC voltage bus via switches, wherein individual and/or a group of DC-to-DC converters can be bypassed in order to keep the DC voltage bus active.

In one configuration of the water-borne vehicle or the power supply unit, the fuel cell modules are spatially separated from the DC-to-DC converters. For example, the fuel cell modules and the DC-to-DC converters are located in different switch cabinets and/or in different spaces. As a result, reliability can be increased, for example.

In one configuration of the water-borne vehicle or the power supply unit, a fuel cell module with a DC-to-DC converter forms a complete module. In this case, a DC-to-DC converter and a fuel cell module are plugged together and/or are screwed together, for example. A space-efficient design can therefore be realized.

In one configuration of the water-borne vehicle or the power supply unit, one DC-to-DC converter (also called a DC/DC controller) is allocated to each fuel cell module respectively. This means that (precisely) one DC-to-DC converter is allocated to (precisely) one fuel cell module. This can relate to an electrical, spatial and/or structural allocation. One independent DC-to-DC converter is thus used for each fuel cell module. This makes it possible to adapt to different application purposes in a simple manner in the form of a series connection. It also results in the series-connected DC-to-DC converters being able to adapt to a failure/defect of a DC-to-DC converter in a simple manner, for example. A failed DC-to-DC converter can be compensated by remaining, active DC-to-DC converters by said DC to-DC converters increasing their voltage output. In this way, not only a failed DC-to-DC converter can be compensated, but also, where applicable, multiple failures of DC-to-DC converters, without the DC voltage on the DC voltage bus having to drop. Up to 2/3 of the DC-to-DC converters can fail depending on the number of series-connected DC-to-DC converters and depending on the maximum voltage swing. However, the cost of this supply reliability for the DC voltage bus may be that the efficiency of the overall system is lower. As a rule, the smaller the voltage swing, the lower the efficiency of a DC-to-DC converter.

In one configuration of the water-borne vehicle or the power supply unit, the fuel cell module has a fuel cell unit and a supply unit for operating materials for supplying the fuel cell unit with the operating materials, wherein the fuel cell unit and the supply unit for operating materials are connected to one another via a connecting plate arranged between the two units. In this case, high availability of the fuel cell system and thus also the individual modules must be ensured. In the event of a defect of a fuel cell, the entire module can be removed from the fuel cell system and, if necessary, can be replaced by an intact module. For this purpose, at least the defective module is in particular brought into a safe state by way of a shutdown procedure - controlled by a higher-level control unit and regulation unit. Once the defective module has been replaced, there is subsequently a power-on procedure. In this case, a "safe" state is intended to be understood to mean in particular a state in which, on the one hand, there are no dangerous contact voltages at the fuel cell unit (voltages lower than 120 V DC, for example) and, on the other hand, in which concentrations of operating materials fall below a predetermined threshold value (hydrogen concentration less than 4 % by volume, for example), so that disconnecting the fuel cell unit from the supply unit for operating materials and thus contacting the fuel cells with the ambient air does not then result in the formation of an explosive fuel/oxygen mixture.

In one configuration of the water-borne vehicle or the power supply unit, the DC-to-DC converters have a galvanic isolation. High supply voltages can thereby be realized by way of the direct galvanic isolation in the controller, i.e. the DC-to-DC converter. The system availability is guaranteed by bypassing one or a plurality of failed controllers, the output voltage of the remaining controllers is correspondingly regulated and/or controlled. Smaller units can make it easier to achieve an exchange. Standard fuel cell modules with DC/DC controllers (DC to-DC converters) can thus be used for smaller and larger systems.

In one configuration of the water-borne vehicle or the power supply unit, the DC-to-DC converters can be bypassed by means of a switch. It is thus possible to replace them when the power supply unit or the fuel cell modules are in operation.

In one configuration of the water-borne vehicle or the power supply unit, the fuel cell modules have an insulation which is different from the DC-to-DC converters. The insulation relates in particular to the insulation strength. High insulation resistances and thus high system voltages by means of water bridges in tubes and ducts are only possible to a limited extent, this can be more easily realized by galvanic isolation in the DC-to-DC converter (DC/DC controller). In this way, a DC voltage bus of over 900V up to several kV, in particular 2 to 3 kV, can be realized in a simple manner.

In one configuration of the water-borne vehicle or the power supply unit, a control unit is connected to the DC-to-DC converters in a data-technical manner. The control unit controls and/or regulates. Depending on the failure of one or a plurality of DC-to-DC converters in a serial circuit, the control unit can increase the voltage output of the remaining active DC-to-DC converters in the serial circuit. In one configuration, this increase completely compensates for the failure. In one configuration, the necessary increase is divided equally in equal parts over the remaining active DC-to-DC converters.

In one configuration of the water-borne vehicle or the power supply unit, the DC voltage bus is spread over the water-borne vehicle as an electrical supply bus. In particular, the DC voltage bus forms at least one part of the on-board power supply and/or represents a main busbar, for example. In one configuration of the water-borne vehicle or the power supply unit, the DC-to-DC converter (DC/DC controller) is specifically adapted to the fuel cell system. Additional redundancy is achieved by way of a parallel circuit of a respective second controller or controller input.

In one configuration of the water-borne vehicle or the power supply unit, the fuel cell modules are connected to a shared supply of operating materials (e.g. to a respective common storage tank for oxygen, hydrogen and nitrogen), for supplying operating materials (e.g. hydrogen, oxygen, cooling water, nitrogen). In this case, fuel cell modules can be used which have an electrical rated output in the single-digit to three digit kW range.

According to a method for operating a power supply unit of a water-borne vehicle or for operating the water-borne vehicle with the power supply unit, DC-to-DC converters electrically power a DC voltage bus in series. The DC-to-DC converters are thus in a series connection. Each DC-to-DC converter contributes its part to the voltage of the DC voltage bus. In particular, each DC-to-DC converter is allocated to one fuel cell module and is connected thereto in at least an electrical manner. This results in a high level of modularity.

In one configuration of the method, if one DC-to-DC converter fails or if a plurality of DC-to-DC converters fail, the output voltage of one or a plurality of remaining DC-to-DC converters is increased. Consequently, the voltage level of a DC voltage bus which is to be powered can be held constant or a voltage drop which is too great can be avoided.

In one configuration of the method, said method can be used in one of the described water-borne vehicles or in one of the described power supply units. The scalability and the reliability of such systems can be improved, in particular in comparison to systems in which one individual DC-to-DC converter outputs the full voltage level of the connected voltage network or voltage bus, by way of the described modularity with respect to the fuel cell modules and the DC-to-DC converters (DC/DC controllers). If fuel cell modules fail, the entire fuel cell system has to be switched off once the voltage falls below a minimum voltage. This can now be avoided. A required voltage level can also be reached by way of a pure series connection of fuel cell modules. This series connection of water-cooled fuel cell modules, for example, limits the voltage level by way of corresponding insulation resistances owing to the compactness, unless the DC-to-DC converters are also connected in series as described, in order to power a DC voltage network (DC voltage bus). If a DC/DC controller is used for the entire system, it is limited by the number of controller inputs. If the controller fails, the entire system can no longer be operated. This can be avoided by way of the series connection of the DC-to-DC converters (DC/DC controllers). The insulation strengths which are possible in conventional controllers cannot be achieved by fuel cell modules operated using waterways or can only be achieved by a very large overall size. This is particularly important for an application which is sensitive to installation sizes. Adapting new systems also requires the controller to be adapted. By connecting the DC-to-DC converters in series, it can be exploited that it is easier and/or more cost-effective to realize a high insulation strength, in particular of several kV, with these than with the fuel cell modules, which are in particular water-cooled. In order to achieve the voltage specifications, fuel cell modules can also be connected in series. The use of DC/DC controllers which are specifically adapted to the fuel cell system and which have a plurality of ducts can also increase reliability in the event of failure of fuel cell modules.

It is easier to realize the necessary insulation distance, i.e. the insulation strength, by means of the displacement of the high voltages and the insulation distances which are therefore necessary, onto the output side of the DC/DC controller. The modular design and the series-connected DC-to-DC converters (DC/DC controllers) increase the reliability of the fuel cell system. In this way, it is possible to develop customized and/or application-specific compact systems.

A variable scaling of fuel cell systems and the voltage specifications thereof is possible by directly linking a DC/DC controller, which is optimized for the voltage level, to a fuel cell module (compact unit made up of both components) and by the resulting displacement of the insulation onto the output side of the controller.

In one configuration of the method for operating the power supply unit of a water-borne vehicle, failures of individual units are compensated by actively regulating the total voltage, and thus the availability of the systems is increased.

Compact standard units made up of a fuel cell module and a DC to-DC converter make a fuel cell system more easily scalable. The modular system can also improve the maintainability of these systems.

The invention is explained in greater detail by way of example using drawings from which further information can be inferred, as well as from the subclaims. In the drawings:

FIG 1 shows a fuel cell module; FIG 2 shows a series connection of DC-to-DC converters and FIG 3 shows a series connection according to FIG 2 in the event of a fault.

The depiction according to FIG 1 shows an example of a configuration of a fuel cell module 1 which has a fuel cell unit 2 and a supply unit for operating materials 3 for supplying the fuel cell unit 2 with the operation materials. As depicted, the fuel cell module 1 has precisely one fuel cell unit 2 and precisely one supply unit for operating materials 3 which is only allocated to this fuel cell unit 2, i.e. the supply unit for operating materials 3 only serves to supply this one allocated fuel cell unit 2 with operating materials. However, it is also possible, but not depicted, that the fuel cell module 1 has precisely one supply unit for operating materials 3 and two or more fuel cell units 2 which are only allocated to this unit and are supplied with operating materials from this unit, for example. The fuel cell unit 2 has a stack 5 of PEM (polymer electrolyte membrane) fuel cells 5' and a stack 6 of humidification cells 6'. The stack 5 is cascaded and has two partial stacks with a stabilizing plate 15 arranged therebetween for this purpose. Cascading can make it possible for the fuel cells to operate very emission-free. The fuel cell unit 2 and the supply unit for operating materials 3 are connected to one another via a connecting plate 4 arranged between the two units. The fuel cell unit 2 additionally has an end plate 7, wherein the stacks 5, 6 are arranged between the connecting plate 2 and the end plate 7. The end plate 7 and the connecting plate 4 are clamped together by means of a tie rod, which is not depicted in greater detail, and thus hold the stacks 5, 6 together. The supply unit for operating materials 3 is likewise connected to the connecting plate 4 and has a terminal plate 9 with electrical connections 10 for tapping a current which is generated in the fuel cells 5' from outside the fuel cell module 1, sensor connections 11 as well as operating material connections 13 for supplying and discharging operating materials (oxygen, hydrogen, nitrogen) to or from the fuel cell module 1. Together with the plates 4, 7, a further intermediate plate 14 delimits the humidification cell stack 6 or the fuel cell stack 5. The plates 4, 14, 15 have a number of operating material ducts which run through the plates and are not shown in FIG 1. The plates 4, 7 outwardly terminate the fuel cell unit 2. The supply unit for operating materials 3 also has auxiliary components for operating the fuel cell module 1. In particular, these are valves for connecting and disconnecting the (external) supply of operating materials, pressure sensors, temperature sensors and/or water separators. Sensors and actuators of the fuel cell module 1 which are not shown in greater detail are connected to a higher-level control unit and regulation unit via corresponding connections in the terminal plate 9 or end plate 7 and signal lines and control lines, for example. The sensor connections 13 are depicted by way of example. Not depicted are any possible busbars which run along the outside of the fuel cell unit 2 and guide the current which is generated by the fuel cells into the supply unit for operating materials 3.

The depiction according to figure 2 shows a power supply unit 24 of a water-borne vehicle, wherein the power supply unit 24 has eight fuel cell modules 1 and eight DC-to-DC converters 16. The eight DC-to-DC converters 16 are electrically connected in series to a DC voltage bus 25. The DC-to-DC converters 16 can be bypassed by means of switches 20. The eight DC-to-DC converters 16 each have an input side 17 and an output side 19. The input side 17 is galvanically isolated from the output side 19 via an insulation 18. The series connection of the DC-to-DC converters 16 forms a part of a DC voltage bus 25. In this way, a DC voltage for a system of 8 x 120V = 960V can be formed, for example. A fuel cell module 1 together with a DC-to-DC converter 16 forms a complete module 22. The fuel cell modules 1 have a grounding 23.

The depiction according to FIG 3 corresponds to that of FIG 2, wherein a fault 26 is depicted. According to FIG 3, a fault has occurred in the fourth complete module with the fuel cell module l' and the DC-to-DC converter 16'. In order to continue to provide power to the DC voltage bus 25 and to make it possible to replace the faulty components l' or 16', the allocated switch ' is closed. The output voltage is increased in the remaining active components, i.e. the fuel cell modules 1 and the DC-to DC converters 16, so that the same DC voltage is set again in the same DC voltage bus 25 according to the equation 7 x 137V = 960V, as without faults. In a corresponding manner, if two or three complete modules fail, this can also be compensated, for example.

The concept of the series-connected DC-to-DC converters 16 makes it possible to achieve at least one of the following advantages: - scalable system concept depending on the vehicle electrical system voltage; - higher system voltages in the DC voltage bus; - small fuel cell units or controller units (DC-to-DC converters) are also suitable for special applications; - by tracking the controller output voltage, failures/faults can be compensated without interrupting operation; - cost-saving effects by standardizing the units; - an insulation strength which is more easily realized by incorporating the main insulation (galvanic isolation) into the controller (DC-to-DC converter) and not into the fuel cell module, which in particular has contact with water and - small units make it possible to carry out a replacement on board the water-borne vehicle more easily (it may be possible to separate a DC-to-DC converter and a fuel cell module (FCM)).

Claims

CLAIMS:

1. A water-borne vehicle having a power supply unit, wherein the power supply unit comprises fuel cell modules and DC-to-DC converters such that each fuel cell module is connected to one of the DC-to-DC converters, wherein the DC-to-DC converters are electrically connected in series to provide electrical power to a DC voltage bus, wherein each of the DC-to-DC converters and the corresponding fuel cell module are configured to be bypassed, wherein, when being bypassed, each fuel cell module is configured to be removable while one or more of the remaining fuel cell modules continue to provide the electrical power to the DC voltage bus, and wherein, when a fuel cell module is removed, the removed fuel cell module is replaced with another fuel cell module.

2. The water-bome vehicle as claimed in claim 1, wherein one DC-to-DC converter is allocated to each fuel cell module respectively.

3. The water-bome vehicle as claimed in claim 1 or 2, wherein the DC-to-DC converters have a galvanic isolation.

4. The water-bome vehicle as claimed in any one of claims I to 3, wherein the bypass of a DC-to-DC converter is performed using a switch.

5. The water-bome vehicle as claimed in any one of claims 1 to 4, wherein the fuel cell modules have an insulation which is different from the DC-to-DC converters.

6. The water-bome vehicle as claimed in any one of claims I to 5, wherein a control unit is connected to the DC-to-DC converters in a data-technical manner.

7. The water-bome vehicle as claimed in any one of claims 1 to 6, wherein the DC voltage bus is spread over the water-borne vehicle as an electrical supply bus.

8. The water-bome vehicle as claimed in any one of claims 1 to 7, wherein each of the fuel cell module comprises a fuel cell unit and a supply unit, wherein the supply unit is configured for supplying operating materials to the fuel cell unit, and wherein the fuel cell unit is configured for generating the electrical power using the supplied operating materials.

9. The water-bome vehicle as claimed in claim 8, wherein the replacement of the fuel cell module comprises disconnecting the supply unit from the fuel cell unit; and replacing the fuel cell unit.

10. The water-bome vehicle as claimed in claim 8 or 9, wherein the supply units are connected to a shared supply of the operating materials.

11. The water-bome vehicle as claimed in any one of claims 1 to 10, further comprising a second power supply unit providing electrical power to the DC voltage bus in parallel to the power supply unit.

12. A method for operating a power supply unit of a water-borne vehicle, wherein the power supply unit comprises fuel cell modules such that each fuel cell module is connected to one of the DC-to-DC converters, wherein the DC-to-DC converters are electrically connected in series to provide electrical power to a DC voltage bus, the method comprising: bypassing one of the DC-to-DC converters and the corresponding the fuel cell module; removing the bypassed fuel cell module, while one or more of the remaining fuel cell modules continue to provide the electrical power to the DC voltage bus; and replacing the removed fuel cell module with another fuel cell module.

13. The method as claimed in claim 12, the method further comprising: if one of the DC-to-DC converters fails, increasing the output voltage of one or a plurality of the remaining DC-to-DC converters.

14. The method as claimed in claim 12 or 13, wherein the bypass of a DC-to-DC converter is performed using a switch.

15. The method as claimed in any one of claims 12 to 14, wherein each of the fuel cell module comprises a fuel cell unit and a supply unit, wherein the supply unit is configured for supplying operating materials to the fuel cell unit, and wherein the fuel cell unit is configured for generating the electrical power using the supplied operating materials.

16. The method as claimed in claim 15, wherein the replacing of the fuel cell module comprises disconnecting the supply unit from the fuel cell unit; and replacing the fuel cell unit.

17. The method as claimed in claim 15 or 16, wherein the supply units are connected to a shared supply of the operating materials.

18. The method as claimed in any one of claims 12 to 17, further comprising providing a second power supply unit configured to provide electrical power to the DC voltage bus, wherein the second power supply unit is in parallel to the power supply unit.

19. The method as claimed in any one of claims 12 to 18, wherein a water-borne vehicle as claimed in one of claims 1 to 7 is used.

Siemens Aktiengesellschaft Patent Attorneys for the Applicant/Nominated Person SPRUSON&FERGUSON