DE102018216232A1 - Online optimization procedure for setting the mode of operation of a fuel cell system - Google Patents

Abstract

The invention relates to an online optimization method for setting the operating mode of a fuel cell system (1) with reference to at least two target variables, comprising the steps: determining operating parameters of the fuel cell system (1), determining in each case one quality factor (G1 - G4) for at least one determined operating parameters, each with a quality factor representing a target variable, calculating a quality function (J) based on the determined quality factors (G1 - G4), determining control variables using the calculated quality function (J), and setting the operating mode of the fuel cell system (1) based on the determined Control variables. The invention further relates to a computer program (6), a storage means, a control unit (7) and a fuel cell system (1) for executing the online optimization process according to the invention.

Description

The present invention relates to an online optimization method for setting the operating mode of a fuel cell system, in particular in the form of a fuel cell vehicle. The invention further relates to a computer program, a storage means and a control device for performing a generic online optimization method. Furthermore, the invention relates to a fuel cell system, in particular in the form of a fuel cell vehicle, with such a control unit.

State of the art

In the case of fuel cell vehicles, as with most mobile energy systems, an energy-optimal operating state should always be sought. For example, the consumption of hydrogen has to be optimized. However, aging or degradation processes can also occur in the fuel cell vehicle or in another fuel cell system, which must be taken into account. One-sided optimization of consumption at the expense of component aging must be avoided.

Current fuel cell vehicles are mostly designed as hybrid vehicles with a fuel cell system and an electrical energy store such as a traction battery or high-voltage battery or with supercapacitors, which together or separately can provide energy for an electric motor for driving the hybrid or fuel cell vehicle. These energy stores must also be taken into account in order to produce an operation that is as energy-optimal as possible with regard to aging or degradation processes.

A large number of different operating strategies are possible in known hybrid vehicles. These operating strategies can lead to different consumption levels and different load profiles or loads on the components and thus to different aging conditions.

From the DE 10 2007 014 617 A1 This shows, for example, a fuel cell system for mobile applications in a hybrid vehicle and a method for controlling such a fuel cell system. According to the DE 10 2007 014 617 A1 Different operating parameters of the hybrid vehicle are taken into account in order to optimally utilize the fuel cell system for driving and at the same time take into account an age-related deterioration in performance. For this purpose, for example, an air volume flow or a fuel mass flow are recorded as operating variables. In addition, a fictitious current is calculated, which is compared with a measured current.

Disclosure of the invention

Within the scope of the present invention, an improved online optimization method for setting the operating mode of a fuel cell system according to claim 1, a computer program according to claim 12, a storage medium according to claim 13, a control device according to claim 14 and a fuel cell system according to claim 15 are proposed. Further advantageous embodiments of the invention result from the description, the subclaims and the figures. Features and details that are described in connection with the online optimization method apply here, of course, also in connection with the computer program according to the invention, the storage medium according to the invention, the control device according to the invention, the fuel cell system according to the invention and vice versa, so that the individual aspects of the invention are always disclosed is or can be mutually referenced.

• - Ermitteln von Betriebsparametern des Brennstoffzellensystems,
• - Ermitteln von jeweils einem Gütefaktor zu jeweils wenigstens einem ermittelten Betriebsparameter, wobei je ein Gütefaktor eine Zielgröße abbildet,
• - Berechnen einer Gütefunktion anhand der ermittelten Gütefaktoren,
• - Ermitteln von Ansteuergrößen mittels der berechneten Gütefunktion, und
• - Einstellen der Betriebsweise des Brennstoffzellensystems anhand der ermittelten Ansteuergrößen.

According to a first aspect of the present invention, an online optimization method for setting the mode of operation of a fuel cell system with respect to at least two target variables is provided. The process has the following steps:

• Determining operating parameters of the fuel cell system,
• Determining a quality factor in each case for at least one determined operating parameter, a quality factor representing a target variable,
• Calculating a quality function based on the determined quality factors,
• - Determination of control variables using the calculated quality function, and
• - Setting the operating mode of the fuel cell system based on the determined control variables.

Using the quality factors in the context of online optimization, a desired trade-off between different target values can be achieved in order to achieve the most efficient, effective and yet system-friendly mode of operation of the fuel cell system. The various goals or the corresponding target values cannot all be optimized simultaneously or independently of one another. With the aid of the method according to the invention, however, an advantageous compromise can be determined with reference to different times and / or depending on operating states and / or an aging behavior of the fuel cell system. The operating mode or corresponding operating strategies used in the fuel cell system can accordingly be individually adapted for different environmental and / or system component states on the basis of the proposed online optimization.
In particular, a variable, changing and / or adjustable quality factor is determined. The quality factor can also be understood as a quality criterion. The quality factor can be determined by calculation or modeling, using sensor values and / or using characteristic maps.

Within the scope of the calculation of the quality function, the quality function can be minimized over a predetermined or definable time period and / or over a predetermined or definable route. The control variables can be determined accordingly using the minimized quality function. This means that various optimization processes can be carried out continuously as part of the calculation of the quality function. In particular, trajectories can be used which result in the minimum of the quality function or by means of which the minimum of the quality function can be determined. With the help of these trajectories, the optimal or desired mode of operation or a corresponding operating strategy can be displayed and then implemented, at least until an update takes place. The minimization or a corresponding optimization can accordingly be trajectories, i.e., courses of operating parameters, environmental parameters, target values and / or control values.

The target values are taken into account as part of the optimization process over a defined period, which can be short-term, medium-term, long-term and / or a combination of these, depending on the prediction options. This means that the trajectories of the operating parameters and the quality factors are taken into account and which are variable in the calculation of the quality function or in the optimization. Limitations or operating limits of individual subsystems of the fuel cell system such as the fuel cell stack, various batteries, the electric motor and / or supercapacitors are taken into account depending on time and / or condition. It should be noted here that the calculation of the quality function is not a calculation on a time step. In other words, as part of the calculation or the minimization or optimization contained therein, the trajectories of all location, time and condition-dependent parameters are taken into account where possible.

In the present case, the fuel cell system is designed in particular in the form of a fuel cell vehicle. The fuel cell vehicle can have a fuel cell, a high-voltage battery as an additional energy store, a starter battery, a supercapacitor and / or an electric motor for driving the fuel cell vehicle. Nevertheless, the present fuel cell system can also be designed in the form of a stationary fuel cell system. Although the fuel cell system is mainly described below with reference to a mobile fuel cell system, the essence of the present inventive concept can also be applied to the stationary fuel cell system. The fuel cell system can in principle be understood to mean any system with at least one fuel cell or with at least one fuel cell stack, for example a Powernet or an energy management system (EMS) with a fuel cell stack and a battery, for example in the form of a high-voltage battery and / or a starter battery for a motor vehicle, as a hybrid energy system or hybrid energy supply system. According to the invention, the fuel cell, power and / or energy flows of the fuel cell system, at least one high-voltage battery, at least one starter battery, at least one DC / DC converter and / or at least one electric motor of the fuel cell system can be set or adapted on the basis of the quality function

Using the proposed procedure, for example, the lowest possible fuel consumption with the least possible aging or with a high degree of protection of the system components of the fuel cell system, such as the battery or high-voltage battery, fuel cell stack, and / or compression system for compressing air for the fuel cell stack, can be achieved.

If the fuel cell system is designed in the form of the fuel cell vehicle, the online optimization can be model-based with models of the fuel cell vehicle, the environment and / or the route to be traveled, the drive system and the energy supply system of the fuel cell vehicle be implemented. The models and the operating strategy can always be dynamically or adaptively adapted to the current state of the fuel cell vehicle using the quality factors and the quality function. This can be achieved, for example, with regard to a vehicle mass, if a load is detected via a function, the surroundings, current air pressures, and / or temperatures by measurement via sensors of the vehicle. Furthermore, the operating limits of various system components can be flexibly adapted. Electrical operating limits such as a maximum and / or minimum power, currents and / or voltages for a high-voltage battery and / or the fuel cell stack can be adapted depending on the respective state of aging.

Für die Gütefunktion J bzw. eine entsprechende Optimierungsfunktion kann für einen Zeitraum t0 bis t1 Folgendes umgesetzt werden: $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[G_1-G_n\right]dt}\right\}$$

In the case of a fuel cell vehicle in the form of a hybrid vehicle, it can be taken into account in the modeling and optimization for an electrical power balance that the electrical power from the energy stores or converters is the sum of the energy of the fuel cell stack and the high-voltage battery, optionally also the energy of the starter battery, is. This can be represented as follows: $$P_{F\mathrm{C.}S,Stack}+P_{HVBat}=P_{EMDrive}+P_{PNT,lOss}+P_{Aux\mathrm{,\; 12th}V}+P_{Aux,HV}$$

The following can be implemented for the quality function J or a corresponding optimization function for a period t0 to t1: $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[G_1-G_n\right]dt}\right\}$$

The minimum of J results in a pareto front, which for example shows a partial quality or a corresponding quality factor G1 for fuel consumption of the fuel cell system and at least one further quality factor Gn for example for an aging state of a high-voltage battery of the fuel cell system in the form of a fuel cell vehicle and / or an aging state of a fuel cell stack Has fuel cell system. Here it can be determined that the better the aging condition, the higher the corresponding quality factors.

The online optimization can be solved, for example, using the Pontryagin minimum principle with the introduction of a Hamilton function, or the quality function can be calculated accordingly, other suitable optimization approaches and / or types of calculation depending on the computing capacity of the fuel cell system including cloud and / or server components, can be used.

entsprechen, wobei unter G1 ein Massenstrom von Wasserstoff bzw. einem anderen Brennstoff in Gewicht pro Zeit entsprechen kann. Gleichwohl ist diesbezüglich auch eine andere Normierung möglich.The quality factor for fuel, especially hydrogen consumption, can $$G_1={\dot{m}}_{H\mathrm{2nd}}$$

correspond, whereby under G1 a mass flow of hydrogen or another fuel can correspond in weight per time. Nevertheless, another standardization is possible in this regard.

wobei im Zähler der die aktuell noch verfügbare maximale Ladekapazität Cact der Hochvoltbatterie und im Nenner die nominale bzw. ursprünglich maximale Ladekapazität Cnominal der Hochvoltbatterie stehen. Unter Cact kann ein Betriebsparameter bzw. ein Zustand oder ein aktueller Grenzwert des Brennstoffzellensystems verstanden werden. Der Gütefaktor G2 kann auch als SOC (State of Charge oder Health) der Hochvoltbatterie bezeichnet werden. Alternativ kann der Gütefaktor G2 beispielsweise auch auf eine Leistungsreduktion bezogen sein. Dies würde sich wie folgt darstellen: $$G_2=\frac{P_{Bat,act}}{P_{Bat,nominal}}$$

Der Alterungszustand des Brennstoffzellenstapels bzw. ein entsprechender Gütefaktor G3 kann wie folgt ermittelt werden: $$G_3=\frac{P_{Stack,act}}{P_{Stack,nominal}}$$

Wobei im Zähler der aktuelle maximale Leistungszustand PStack,act und im Nenner der nominale bzw. maximale Leistungszustand PStack,nominal des Brennstoffzellenstapels stehen. Alternativ zur maximalen Leistung kann der Alterungszustand auch bei einer definierten Teillast ermittelt werden. PStack,act kann als Betriebsparameter bzw. ein Zustand oder ein aktueller Grenzwert des Brennstoffzellensystems verstanden werden.The aging status of the high-voltage battery or a corresponding quality factor G2 can be determined as follows: $$G_{\mathrm{2nd}}=\frac{{\mathrm{C.}}_{act}}{{\mathrm{C.}}_{nOminal}}$$

whereby the numerator contains the currently still available maximum charging capacity Cact of the high-voltage battery and the denominator shows the nominal or originally maximum charging capacity Cnominal of the high-voltage battery. Cact can be understood to mean an operating parameter or a state or a current limit value of the fuel cell system. The quality factor G2 can also be referred to as the SOC (State of Charge or Health) of the high-voltage battery. Alternatively, the quality factor G2 can also relate to a power reduction, for example. This would look like this: $$G_{\mathrm{2nd}}=\frac{P_{Bat,act}}{P_{Bat,nOminal}}$$

The aging condition of the fuel cell stack or a corresponding quality factor G3 can be determined as follows: $$G_{\mathrm{3rd}}=\frac{P_{Stack,act}}{P_{Stack,nOminal}}$$

The current maximum performance state PStack, act is in the numerator and the nominal or maximum performance state PStack, nominal of the fuel cell stack is in the denominator. As an alternative to the maximum output, the aging condition can also be determined at a defined partial load. PStack, act can be understood as an operating parameter or a state or a current limit value of the fuel cell system.

Die erfindungsgemäße Optimierung kann sich abhängig davon, welche Informationen zur Verfügung stehen bzw. wie hoch der Automatisierungsgrad und/oder der Vernetzungsgrad des Brennstoffzellensystems ist, auf verschiedene Zeithorizonte beziehen. So kann die Online-Optimierung über einen kurzfristen Zeitraum, einen mittelfristigen Zeitraum und/oder einen langfristigen Zeitraum durchgeführt und entsprechend adaptiv eingestellt werden. Die Online-Optimierung kann lokal über ein Steuergerät des Brennstoffzellensystems und/oder Server/Cloud-basiert durchgeführt werden. Die Optimierung kann periodisch, je nach Aufwand, Rechenkapazität, und/oder Rechenzeit, wiederholt, beispielsweise in einem 100ms oder 1000ms Raster oder in einem dynamischen Rechenraster durchgeführt werden. Diese Wiederholungsrate hat sich bei umfangreichen Versuchen im Rahmen der vorliegenden Erfindung für bestimmte Anwendungsfälle als überraschend vorteilhaft herausgestellt. Ein Ansteuervektor kann für alle Aktoren entsprechend aktualisiert werden. Entsprechend ist die Optimierung mittels der Trajektorien über einen Kurzzeit-, Mittelfrist, und/oder Langzeithorizont möglich bzw. kann über einen vordefinierbaren Zeithorizont durchgeführt werden.The quality function J would look as follows in the aforementioned case: $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[G_1-G_{\mathrm{2nd}}-G_{\mathrm{3rd}}\right]dt}\right\}$$

The optimization according to the invention can relate to different time horizons depending on what information is available or how high the degree of automation and / or the degree of networking of the fuel cell system is. In this way, online optimization can be carried out over a short-term period, a medium-term period and / or a long-term period and adjusted accordingly. The online optimization can be carried out locally via a control unit of the fuel cell system and / or server / cloud-based. The optimization can be carried out periodically, depending on the effort, computing capacity and / or computing time, repeatedly, for example in a 100 ms or 1000 ms grid or in a dynamic computing grid. This repetition rate has been found to be surprisingly advantageous for certain applications in extensive tests within the scope of the present invention. A control vector can be updated accordingly for all actuators. Accordingly, the optimization by means of the trajectories is possible over a short-term, medium-term, and / or long-term horizon or can be carried out over a predefinable time horizon.

The proposed method can be implemented or carried out in the operating strategy of fuel cell systems and / or in mobile applications with hybrid energy supply systems. The method can be used in particular in networked fuel cell vehicles. It can be used with different degrees of automation, i.e. in the context of partially automated systems to fully automated systems, for example in the form of autonomous fuel cell vehicles.

According to a further embodiment of the present invention, it is possible for a target variable to include an aging state of a compressor system for compressing air for a fuel cell stack of the fuel cell system. In extensive studies within the scope of the present invention, this has surprisingly proven to be particularly helpful for the desired setting of the mode of operation of the fuel cell system. The compressor system of the present fuel cell system preferably has a radial compressor.

According to the invention, it can be advantageous in a method if at least one further target variable comprises an aging condition of a high-voltage battery, an aging condition of a starter battery, an aging condition of a fuel cell stack, a hydrogen consumption of the fuel cell system and / or an aging condition of a supercapacitor.

Weiterhin ist es möglich, dass die Gewichtungsfaktoren bei einem erfindungsgemäßen Verfahren abhängig von den ermittelten Gütefaktoren erstellt werden. Dadurch kann unterschiedlichen Gütefaktoren in unterschiedlichen Betriebszuständen des Brennstoffzellensystems adaptiv und besonders einfach Rechnung getragen werden. Beispielsweise kann ein Gewichtungsfaktor erhöht werden, sobald erkannt wird, dass eine Batterie stark gealtert ist, wodurch die Batterie geschont werden kann.It can be a further advantage if, in a method according to the present invention, each quality factor for evaluating the respective target variable is multiplied by a weighting factor. It is also possible that the weighting factors are created depending on the state of the fuel cell system. This makes it possible to take different importance of different quality factors into account accordingly. This can also be done adaptively while the present optimization method is being carried out. The weighting factors can also be defined as a function of the operating states of the fuel cell system, that is to say, for example, as a function of a starting process, a stopping process, an idling operation, a power operation and / or a cold start. If a quality criterion is not required, the weighting factor can simply be set to zero. The quality function including the weighting factors can be represented as follows, G1 for example for the hydrogen consumption and Gn stands for further quality factors such as the aging condition of the battery, the aging condition of the fuel cell stack and / or the aging condition of the air compressor system. $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[f_1{G}_1-{\displaystyle \sum _{n=\mathrm{2nd}}^N{f}_n{G}_n}\right]dt}\right\}$$

Furthermore, it is possible for the weighting factors to be created in a method according to the invention depending on the quality factors determined. As a result, different quality factors can be taken into account adaptively and particularly simply in different operating states of the fuel cell system. For example, a weighting factor can be increased as soon as it is recognized that a battery has aged significantly, which can save the battery.

wobei NmaxDesign die für die Auslegung relevante Anzahl von zulässigen Start-Stopp-Vorgängen und Nact die bisherige bzw. aktuelle Anzahl von Start-Stopp-Vorgängen ist. Nact kann als Betriebsparameter des Brennstoffzellensystems verstanden werden. Alternativ könnte auch die Zeit und/oder eine vordefinierte Anzahl von Rotationen, beispielsweise eine Drehzahl unterhalb einer Abhebedrehzahl, herangezogen werden. Die vorstehend eingeführte Funktion könnte in diesem Fall wie folgt aussehen, wobei die Gewichtungsfaktoren optional sind. $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[f_1{G}_1-f_1{G}_4\right]dt}\right\}$$

Alternativ kann auch die Anzahl NnomToUse berücksichtigt werden, die bis zum aktuellen Stand, auf Betriebsstunden oder Fahrstrecke bezogen, gemäß Design des Verdichtersystems akzeptabel wäre. Dies kann sich wie folgt darstellen bzw. berechnen lassen. $$G_4=\{\begin{array}{ccc}1& f\ddot{u}r& N_{act}<N_{nomToUse}\\ 1-\frac{N_{act}-N_{nomToUse}}{N_{maxDesign}-N_{nomToUse}}& f\ddot{u}r& N_{act}\ge N_{nomToUse}\end{array}$$

Ist das Brennstoffzellensystem bei einer weiteren Ausgestaltungsvariante der vorliegenden Erfindung in Form eines Brennstoffzellenfahrzeugs ausgestaltet, ist es möglich, dass anhand der berechneten Gütefunktion ein Drehmoment eines Elektromotors des Brennstoffzellenfahrzeugs zum Antreiben des Brennstoffzellenfahrzeugs, eine verfügbare Gesamtleistung des Brennstoffzellenfahrzeugs und/oder eine Leistungsverzweigung zu verschiedenen Energielieferanten des Brennstoffzellensystems wie Hochvoltbatterie, Superkondensator, und/oder Starterbatterie eingestellt werden. D.h., die Stellvariablen für eine Optimierung bzw. entsprechende Einstellung der Betriebsweise des Brennstoffzellensystems kann das Drehmoment des Elektromotors bzw. eines entsprechenden Elektroantriebs und/oder die verfügbare und/oder benötigte Gesamtleistung des Brennstoffzellensystems und/oder die Aufteilung der Leistung auf die Energielieferanten sein. Anhand der Leistungsverzweigung kann festgelegt werden, wie viel Leistung bzw. Energie von welchem Energielieferanten angefordert werden soll. Ist die Stellvariable das Drehmoment des Elektromotors, kann für eine Optimierung bzw. verbesserte Einstellung der Betriebsweise des Brennstoffzellensystems die Aufteilung eines Bremsmomentes zwischen Elektromotor und Reibbremse, d.h., eine flexible Rekuperation, berücksichtigt werden. Wird die Rekuperation nicht flexibel mit Freiheitsgrad angewandt, kann die Stellvariable für die Optimierung die benötigte Gesamtleistung aus dem Brennstoffzellensystem bzw. dem entsprechenden Energiesystem des Brennstoffzellensystems sein. Eine Ansteuer-Vorgabe bzw. entsprechende Ansteuergrößen für die Leistungsverzweigung zwischen verschiedenen Energielieferanten wird bzw. werden bevorzugt mittels DC/DC-Wandler umgesetzt. D.h., der DC/DC-Wandler wird entsprechend einer Optimierungsvorgabe angesteuert, sodass die gewünschten Leistungen bzw. Energiemengen aus den jeweiligen Systemen geliefert werden. Zusätzlich oder alternativ kann das Start-Stopp-Verhalten des Verdichtersystems dem optimierten Kompromiss bzw. Trade-off entsprechend eingestellt werden.In addition, in a method according to the present invention, it is possible for a quality factor for the aging state of a compressor system to be based on a ratio of a number of start / stop processes of the compressor system in the fuel cell vehicle to a predefined number of start / stop processes of the compressor system is determined in the fuel cell vehicle. As mentioned above, particularly advantageous results could be achieved in experiments within the scope of the present invention. Since very high speeds are required in generic compressor systems, in particular radial compressors, the associated bearings are often designed as air-lubricated bearings or gas bearings. However, these are age-sensitive with regard to start-stop processes due to the increased friction that occurs. The number of start-stop operations N occurring can be used as a criterion for such arrangements. $$G_{\mathrm{4th}}=1-\frac{N_{act}}{N_{maxDesiGn}}$$

where NmaxDesign is the number of permitted start-stop processes relevant for the design and Nact is the previous or current number of start-stop processes. Nact can be understood as an operating parameter of the fuel cell system. Alternatively, the time and / or a predefined number of rotations, for example a speed below a lift-off speed, could also be used. In this case, the function introduced above could look as follows, with the weighting factors being optional. $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[f_1{G}_1-f_1{G}_{\mathrm{4th}}\right]dt}\right\}$$

Alternatively, the number of NnomToUse can be taken into account that would be acceptable up to the current status, based on operating hours or driving distance, according to the design of the compressor system. This can be represented or calculated as follows. $$G_{\mathrm{4th}}=\{\begin{array}{ccc}1& f\ddot{u}r& N_{act}<N_{nOmTOUse}\\ 1-\frac{N_{act}-N_{nOmTOUse}}{N_{maxDesiGn}-N_{nOmTOUse}}& f\ddot{u}r& N_{act}\ge N_{nOmTOUse}\end{array}$$

If the fuel cell system is configured in the form of a fuel cell vehicle in a further embodiment variant of the present invention, it is possible that, based on the calculated quality function, a torque of an electric motor of the fuel cell vehicle for driving the fuel cell vehicle, an available total power of the fuel cell vehicle and / or a power split to various energy suppliers Fuel cell systems such as high-voltage battery, supercapacitor, and / or starter battery can be set. That is, the control variables for an optimization or corresponding setting of the operating mode of the fuel cell system can be the torque of the electric motor or a corresponding electric drive and / or the available and / or required total power of the fuel cell system and / or the distribution of the power to the energy suppliers. The power split can be used to determine how much power or energy should be requested from which energy supplier. If the control variable is the torque of the electric motor, optimization or improved setting of the mode of operation of the fuel cell system, the division of a braking torque between the electric motor and friction brake, that is, flexible recuperation, are taken into account. If the recuperation is not used flexibly with a degree of freedom, the control variable for the optimization can be the total power required from the fuel cell system or the corresponding energy system of the fuel cell system. A control specification or corresponding control variables for the power split between different energy suppliers is or are preferably implemented by means of a DC / DC converter. This means that the DC / DC converter is controlled in accordance with an optimization specification, so that the desired outputs or amounts of energy are supplied from the respective systems. Additionally or alternatively, the start-stop behavior of the compressor system can be set according to the optimized compromise or trade-off.

According to a further aspect of the present invention, a computer program is provided, comprising instructions which, when the computer program is executed by a computer or another computing unit, cause the latter to carry out the method described above. The computer program according to the invention thus brings with it the same advantages as have been described in detail with reference to the device according to the invention. The computer program can be implemented as computer-readable instruction code in any suitable programming language such as, for example, JAVA, C ++ or C #. The computer program can be stored on a computer-readable storage medium such as a data disc, a removable drive, volatile or non-volatile memory, or a built-in memory / processor. The instruction code can program a computer or other programmable device such as the controller to perform the desired functions. Furthermore, the computer program can be provided in a network, such as the Internet, from which it can be downloaded by a user if required. The computer program can be implemented both by means of software and by means of one or more special electronic circuits, i.e. in hardware in the form of a computer program product, or in any hybrid form, i.e. by means of software components and hardware components.

In addition, a storage means, for example in the form of a hard disk or another mobile data storage device, with a computer program stored thereon, which is configured to carry out a method as described above, and a control device with a computer program installed thereon, to carry out a method as described above configured and configured, provided. In addition, a fuel cell system, in particular a fuel cell vehicle, is provided with such a control device for setting the operating mode of the fuel cell system or the fuel cell vehicle according to a method as described above. The storage means according to the invention, the control device according to the invention and the fuel cell system according to the invention thus also bring with them the advantages described above.

Further measures improving the invention result from the following description of some exemplary embodiments of the invention, which are shown schematically in the figures. All of the features and / or advantages arising from the claims, the description or the drawing, including structural details and spatial arrangements, can be essential to the invention both individually and in the various combinations.

• 1 ein Flussdiagramm zum Erläutern eines Online-Optimierungsverfahrens gemäß einer Ausführungsform der vorliegenden Erfindung,
• 2 ein Brennstoffzellenfahrzeug gemäß einer Ausführungsform der vorliegenden Erfindung, und
• 3 ein Blockschaltbild zum Erläutern der Betriebsweise eines Brennstoffzellensystems gemäß einer Ausführungsform der vorliegenden Erfindung.

Show it:

• 1 1 shows a flowchart for explaining an online optimization method according to an embodiment of the present invention.
• 2nd a fuel cell vehicle according to an embodiment of the present invention, and
• 3rd a block diagram for explaining the operation of a fuel cell system according to an embodiment of the present invention.

1 shows a flowchart for explaining an online optimization method for setting the operation of a fuel cell system 1 in the form of a fuel cell vehicle or a hybrid energy system with reference to different targets. According to a first step S1 are first operational parameters of the fuel cell system 1 determined. More specifically, operating parameters for a fuel or hydrogen consumption, a fuel cell stack 2nd , a high-voltage battery 3rd and a compressor of the fuel cell system 1 determined. In a subsequent step S2 a quality factor for each of the determined operating parameters is determined on the basis of various calculations, models and / or sensor values, a quality factor representing a target variable. After that, in a third step S3 a quality function J is calculated based on the determined quality factors. As mentioned above, in particular, optimization is carried out in the form of minimization. That is, the trajectories are determined so that the quality function J delivers a minimum value. The quality function J is calculated and optimized for an operating section, for example an entire route or a partial route. In a fourth step S4 control variables are determined using the calculated quality function. This is followed in a fifth step S5 the mode of operation of the fuel cell system 1 based on the determined control variables. More specifically, the operation of the fuel cell system 1 based on the result of the optimized quality function via a torque of an electric motor 5 or the drive motor of the fuel cell vehicle, set by the power split via DC / DC converter and / or a start-stop behavior of the compressor system of the fuel cell system. The control trajectory or a vector for the control of the various actuators, which leads to the smallest value of the quality function J, corresponds to the optimal control sought and is used in the step S5 implemented.

The optimization or the method is carried out again continuously, so that changed boundary conditions or disturbance variables or changed driver's request or changed route are continuously taken into account.

wobei bezüglich der einzelnen Faktoren zur Vermeidung redundanter Beschreibungsteile auf die vorstehende Erläuterung Bezug genommen werden soll. Wie aus der vorstehenden Formel und mit Bezug auf die vorstehende Ausführung zu G4 zu entnehmen, wird unter anderem der Betriebsparameter Nact zum Alterungszustand des Verdichtersystems zum Verdichten von Luft für den Brennstoffzellenstapel 2 des Brennstoffzellensystems 1 ermittelt. Genauer gesagt wird der Gütefaktor G4 anhand eines Verhältnisses einer Anzahl von bisher aufgetretenen Start-Stopp-Vorgängen des Verdichtersystems im Brennstoffzellenfahrzeug zu einer vordefinierten Anzahl an Start/Stopp-Vorgängen des Verdichtersystems im Brennstoffzellenfahrzeug ermittelt. Außerdem wird jeder Gütefaktor zur Bewertung des jeweiligen Betriebsparameters bzw. des daraus resultierenden Gütefaktors jeweils mit einem Gewichtungsfaktor multipliziert. Die Gewichtungsfaktoren werden hierbei abhängig von den ermittelten Gütefaktoren und von den Zuständen des Brennstoffzellensystems erstellt. Wenn Betriebsparameter zum Verdichtungssystem bzw. des Verdichtungssystems eine hohe Wichtigkeit haben wird der zugehörige Gewichtungsfaktor entsprechend hoch eingestellt. Wenn Betriebsparameter zur bzw. der Hochvoltbatterie eine geringe Wichtigkeit aufweisen, wird der zugehörige Gewichtungsfaktor entsprechend niedrig eingestellt oder auf null gesetzt. Die Gütefaktoren G1 bis G3 werden wie vorstehend im Detail beschrieben berechnet.According to a preferred embodiment, the following equation can be established on the basis of the Pontryagin minimum principle with the introduction of a Hamilton function and then solved. $$\text{min}\left\{J={\displaystyle \underset{t0}{\overset{t1}{\int }}\left[f_1{G}_1-f_{\mathrm{2nd}}{G}_{\mathrm{2nd}}-f_{\mathrm{3rd}}{G}_{\mathrm{3rd}}-f_{\mathrm{4th}}{G}_{\mathrm{4th}}\right]dt}\right\}$$

with regard to the individual factors to avoid redundant parts of the description, reference should be made to the above explanation. As can be seen from the above formula and with reference to the above version of G4, the operating parameter Nact, among other things, becomes the aging state of the compressor system for compressing air for the fuel cell stack 2nd of the fuel cell system 1 determined. More precisely, the quality factor G4 is determined on the basis of a ratio of a number of start-stop processes of the compressor system in the fuel cell vehicle to a predefined number of start / stop processes of the compressor system in the fuel cell vehicle. In addition, each quality factor is multiplied by a weighting factor in order to evaluate the respective operating parameter or the resulting quality factor. The weighting factors are created depending on the determined quality factors and on the states of the fuel cell system. If operating parameters for the compression system or the compression system are of great importance, the associated weighting factor is set accordingly high. If operating parameters for the high-voltage battery are of minor importance, the associated weighting factor is set correspondingly low or set to zero. The quality factors G1 to G3 are calculated as described in detail above.

2nd shows a fuel cell system 1 in the form of a fuel cell vehicle with a control unit 7 for setting the mode of operation of the fuel cell system 1 . For this is in the fuel cell system 1 a computer program 6 installed, which includes commands required to run the computer program 6 cause the control unit to carry out the procedure in question.

As in 2nd shown, the fuel cell vehicle further comprises a fuel cell stack 2nd , a high-voltage battery 3rd , a fuel tank 4th and an electric motor 5 on.

In 3rd FIG. 12 is a block diagram for explaining the operation of the fuel cell system 1 shown in the form of the fuel cell vehicle. The control unit plays a central role in this 7 of the fuel cell vehicle, although the functionality could also be implemented by a cloud and / or server solution. The control unit 7 receives information from the environment through a sensor system of the fuel cell vehicle and / or from a decentralized, networked system such as a cloud and / or a decentralized server 11 of the fuel cell vehicle, a driver 12th the fuel cell vehicle or its actions in the fuel cell vehicle, and other vehicle components 13 . In addition, the control unit receives 7 Information from diagnostic components 8th of the fuel cell vehicle. The control unit can provide further information 7 from an energy system 9 get in which of the fuel cell stack 2nd who have favourited High Voltage Battery 3rd , the fuel tank 4th and the compressor system are implemented. Based on this information and with the help of the computer program 6 can the control unit 7 now the mode of operation of the fuel cell vehicle via the drive train 10th the fuel cell vehicle as desired.

In addition to the illustrated embodiments, the invention permits further design principles. That is, the invention should not be considered limited to the exemplary embodiments described for the figures.

QUOTES INCLUDE IN THE DESCRIPTION

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Patent literature cited

• DE 102007014617 A1 [0005]

Claims (15)

Online optimization method for setting the operating mode of a fuel cell system (1) with reference to at least two target values, comprising the steps: - Determining operating parameters of the fuel cell system (1), - Determining a quality factor (G1 - G4) for at least one determined operating parameter, with a quality factor (G1 - G4) each representing a target variable, - calculating a quality function (J) based on the determined quality factors (G1 - G4), - Determination of control variables using the calculated quality function (J), and - Setting the mode of operation of the fuel cell system (1) based on the determined control variables. Procedure according to Claim 1 , characterized in that a target variable comprises an aging state of a compressor system for compressing air for a fuel cell stack (2) of the fuel cell system (1). Procedure according to Claim 2 , characterized in that a quality factor (G4) for the aging state of a compressor system is determined on the basis of a ratio of a number of start-stop processes that have occurred in the fuel cell vehicle to a predefined number of start / stop processes in the fuel cell vehicle. Method according to one of the preceding claims, characterized in that at least one further target variable comprises an aging state of a high-voltage battery, an aging state of a starter battery, an aging state of a fuel cell stack and / or an aging state of a supercapacitor. Method according to one of the preceding claims, characterized in that a still further target variable comprises a hydrogen consumption of the fuel cell system. Method according to one of the preceding claims, characterized in that each quality factor (G1 - G4) for evaluating the respective target variable is multiplied by a weighting factor (f1 - f4). Procedure according to Claim 6 , characterized in that the weighting factors (f1 - f4) are created depending on the determined quality factors. Procedure according to one of the Claims 6 and 7 , characterized in that the weighting factors (f1 - f4) are created depending on the state of the fuel cell system. Method according to one of the preceding claims, characterized in that the fuel cell system (1) is designed in the form of a fuel cell vehicle and, based on the calculated quality function (J), a torque of an electric motor (5) of the fuel cell vehicle for driving the fuel cell vehicle, an available total power of the fuel cell vehicle, a start / stop behavior of an air compressor system and / or a power split to different energy suppliers of the fuel cell system (1) are set. Method according to one of the preceding claims, characterized in that when calculating the quality function (J) to determine a minimum of the quality function (J), trajectories are calculated, the calculation of the trajectories being calculated over a predefinable time horizon and / or over a predefinable route . Method according to one of the preceding claims, characterized in that the calculation of the quality function (J) is carried out periodically, in particular with a time interval in a range between 100 ms and 1000 ms. Computer program (6), comprising commands which cause the computer program (6) to be executed by a computer, the method according to one of the Claims 1 to 11 to execute. Storage means with a computer program (6) stored thereon which is used to carry out a method according to one of the Claims 1 to 11 configured and configured. Control unit (7) with a computer program (6) installed thereon Claim 12 which is used to carry out a method according to one of the Claims 1 to 11 configured and configured. Fuel cell system (1) with a control unit (7) Claim 12 for setting the operating mode of the fuel cell system (1) according to a method according to one of the Claims 1 to 11 .

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