Method, device and system for controlling a heating process of a fuel cell system

Abstract

Control procedure (10) for controlling a heating process of a fuel cell system (200), comprising the following steps: - Recording at least one component temperature profile (KT1, KT2, KT3) of at least one component (201, 202, 203) of the fuel cell system (200), characterized by - Determining a component temperature gradient (CTG) for the recorded component temperature profile (CT1, CT2, CT3), - Comparison of the determined component temperature gradient (CTG) with a gradient setpoint (CTS), and - Increasing the heating power (HL) of a heating device (190) for heating the component (201, 202, 203) until the determined component temperature gradient (KTG) reaches the gradient setpoint (KGS).

Description

[0001] The invention relates to a control method and a control device for monitoring the heating process of a fuel cell system, in which at least one component temperature profile of a component of the fuel cell system is recorded and the heating power of a heating device is adjusted. The invention further relates to a fuel cell system with the aforementioned control device.

[0002] Solid oxide fuel cells (SOFCs) and solid oxide electrolyzer cells (SOECs) operate at relatively high temperatures. Operating temperatures can range from 600°C to 1000°C. Accordingly, the components of such solid oxide systems are designed to withstand thermal stresses at these temperatures. Additional technical challenges, also related to the thermal stress on components, arise during the heating of these solid oxide systems. For example, some components have limited heating rates. This means that the components have a limit to the increase in their core temperature within a defined period. Excessive heating rates can lead to material fatigue or damage to the components. For instance, uneven expansion can occur, which can lead to breakage or impaired functionality of the components.Accordingly, a suitable heating strategy must be provided for the heating process of solid oxide systems.

[0003] It is known from the prior art to continuously increase the heating power required for the heating process. The necessary parameterization is determined in experiments on the solid oxide system with different heating curves. To limit the heating rate, the component with the lowest permissible heating rate is usually selected, and its core temperature is monitored during heating. After determining an optimal heating curve, this curve is saved and reused for controlling future heating processes.

[0004] One disadvantage of such solutions is that the components and their materials can change their thermal conductivity, heat absorption capacity, and heat losses over time. The heating components can also degrade over their lifespan. Consequently, the heat supplied for heating may be distributed differently within the solid oxide system as the operating time increases compared to when the optimal heating curve was determined. This can lead to a sensitive component being heated at an unsuitable, excessively high rate due to the reduced heat absorption of other components. Similar effects can occur when components are replaced or exchanged during maintenance. Re-determining an optimal heating curve is often not feasible due to time and cost constraints.Therefore, compliance with limitations in the heating rate of individual components cannot be guaranteed over the operating lifetime of the solid oxide system, which can have a detrimental effect on the safety and service life of sensitive components.

[0005] Another disadvantage of known solutions is that, for safety reasons, a heating curve with a deliberately low heating rate is often chosen, resulting in slower heating than actually necessary. Consequently, the heating efficiency is reduced and the heating process is unnecessarily prolonged.

[0006] Furthermore, it must be considered that the heating power requirement at the beginning of a heating process can often be higher than at the end. A purely continuous, constant increase in heating power can therefore be disadvantageous. This is because, with such a heating strategy, more heat is supplied from the outside at a certain point in the heating process than would be necessary to maintain the heating rate limitation. The location of this point is determined by the amount of heat input absorbed by the solid oxide system and is not precisely known. In particular, the location of this point may depend on environmental factors that, for example, were not present when determining the optimal heating curve. Thus, the solutions known from the prior art lack the flexibility to react to process-related changes in heat absorption by adjusting the heating rate.

[0007] It is therefore an object of the present invention to at least partially overcome the disadvantages described above. In particular, an object of the invention is to control a heating process in such a way that a compromise can be achieved between rapid heating and the protection of the components of a solid oxide system from excessive heating and damage.

[0008] The foregoing problem is solved by a control method having the features of claim 1, by a control device having the features of claim 13 and a fuel cell system having the features of claim 15.

[0009] Further advantages and features of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the control method according to the invention naturally also apply in connection with the control device and / or the fuel cell system according to the invention, and vice versa, so that the disclosure regarding the individual aspects of the invention always refers to and can refer to each other.

[0010] One aspect of the present invention relates to a control method for monitoring the heating process of a fuel cell system. The method comprises a step in which at least one component temperature profile of at least one component of the fuel cell system is recorded. Furthermore, a component temperature gradient is determined for the recorded component temperature profile. The determined component temperature gradient is compared with a gradient setpoint. In a further step, the heating power of a heating device for heating the component is increased until the determined component temperature gradient reaches the gradient setpoint. The gradient setpoint corresponds, in particular, to a gradient limit of the weakest component of the fuel cell system. Thus, within the scope of the invention, the gradient setpoint can also be referred to as the component gradient setpoint.

[0011] In other words, the invention provides a control method that enables and implements the control of a heating process in a fuel cell system. In particular, it makes it possible to control the heating process even when, for example, system parameters such as air mass flow change and / or different ambient conditions cause different heat losses.

[0012] Within the scope of the invention, a fuel cell system can be understood in particular as a system of fuel cells. The fuel cells can preferably be operated as electrolyzer units and / or as converter units for converting fuels into electrical energy. The fuel cell system according to the invention can in particular be a high-temperature fuel cell system, a solid oxide fuel cell system (SOFC), and / or a solid oxide electrolyzer system (SOEC).

[0013] Within the scope of the invention, a heating process can be understood in particular as a temporal sequence in which the fuel cell system is gradually heated by a defined heat input.

[0014] Furthermore, controlling a heating process can be understood in particular as controlling and regulating it. For example, the sequence and intensity of the heating process can be controlled.

[0015] In the method according to the invention, at least one component temperature profile of at least one component is recorded.

[0016] Capturing a component temperature profile can be understood, in particular, as providing temperature data available at various times. However, it is also conceivable that, when capturing the component temperature profile, such temperature data is directly obtained from a sensor.

[0017] A component of a fuel cell system can be understood as, in particular, a part or functional section of the fuel cell system. For example, the fuel cell stack itself or a component required for the operation of the fuel cell system can be considered a component. These latter components are often grouped under the term Balance of Plant (BoP) and can include, for example, reformers, sensors, pumps, compressors, blowers, heat exchangers, or seals.

[0018] According to the invention, a component temperature gradient is determined for the detected component temperature profile.

[0019] Within the scope of the invention, a temperature gradient can be understood in particular as a rate of change of temperature normalized to a unit of time. Determining can be understood in particular as calculating, approximating, and / or estimating the temperature gradient.

[0020] The determined component temperature gradient is compared with a target gradient value. In a further step, the heating power of a heating device is increased to heat the component until the determined component temperature gradient reaches the target gradient value.

[0021] Within the scope of the invention, heating power can be understood in particular as thermal energy occurring per unit of time, which is to be supplied to the fuel cell system.

[0022] Furthermore, within the scope of the invention, reaching the gradient setpoint can be understood, in particular, as the component temperature gradient approaching the gradient setpoint from below. The gradient setpoint can also be undershot or exceeded by the component temperature gradient within a tolerance range. Exceedances of the gradient setpoint are preferably only temporary and for relatively short periods, for example, up to 10 seconds. The tolerance range can, for example, be defined by a symmetrical deviation of 5%, 2%, 1%, or 0.5% of the gradient setpoint on both sides. Of course, it is also conceivable that the tolerance range is asymmetrical. Thus, the tolerance range for exceedances of the limit value can be smaller than for falls below it.

[0023] The invention thus makes it possible to control the heating process using a gradient-based approach. It enables the implementation of heating process control based on a variable that is not directly measurable. Since the control method determines the instantaneous heating rate of at least one component, it allows for flexible responses to changes in the fuel system's heat absorption behavior and / or heat losses. At the same time, there is no need to intentionally reduce the heating rate to safeguard the integrity of sensitive components. In this way, the fuel cell system can be heated as quickly as possible. This is advantageous because no safety-related reduction of the heating rate is required.On the other hand, the control method only observes the actual temperature gradient, thus always allowing an increase in heating power if the limit is undershot. Unlike solutions known from the prior art, the control method according to the invention therefore allows limitations on the heating rate of individual components to be observed without having to unnecessarily reduce the heating rate. Furthermore, it enables an increase in the degree of automation of heating processes in a fuel cell system.

[0024] According to a preferred embodiment, the heating power can be increased according to a heating control function, in particular according to a defined heating gradient. Preferably, the heating power can be limited between two limit values ​​according to the heating control function. Alternatively or additionally, the heating power can be increased at least partially monotonically continuously and / or monotonically incrementally according to the heating control function.

[0025] This allows for precise and continuous adjustment of the heating output. In particular, the heating control function can be adapted to the specific control situation, thus reducing the risk of over-regulation.

[0026] The heating control function can be understood in particular as a function for determining the heating output to be increased.

[0027] According to a further preferred embodiment, the heating control function can include a gradient PID controller. The gradient PID controller can take the determined component temperature gradient and the gradient setpoint as input parameters.

[0028] This method thus makes it possible to consider the response of the component temperature gradient to past increases in heating power when increasing the heating output, as well as to incorporate forecasts of the future course of the component temperature gradient. Furthermore, this design allows for a reactive increase in heating power.

[0029] According to a preferred embodiment, the heating control function can be based on the detected component temperature profile of at least one other component of the fuel cell system as an input parameter. The heating control function can include at least one additional PID controller to limit the heating power depending on the detected component temperature profile. Preferably, the heating power can also be limited by the additional PID controller depending on a temperature limit specific to the other component. Furthermore, the heating control function can include a selection criterion to choose between the heating power to be increased according to the heating control function of the gradient PID controller and the heating power to be limited according to the heating control function of the additional PID controller.For example, the selection criterion can be a minimum of the heating power to be increased according to the heating control function of the gradient PID controller and the heating power to be limited according to the temperature limit of the additional PID controller.

[0030] This allows for an increase in heating power while considering the temperature profiles of multiple components. Furthermore, local variations in the temperature behavior of the fuel cell system can also be taken into account. Using simultaneously running PID controllers, it can be ensured that, before increasing the heating power, the system verifies how to increase it without damaging fuel cell system components through excessively rapid heating. This selection criterion allows the user to integrate such safety mechanisms into the control procedure.

[0031] Alternatively or additionally, the selection criterion can be based on a comparison of at least one of the recorded component temperature profiles with a temperature range limit. The heating power can then be increased according to the heating control function of the gradient PID controller for temperatures corresponding to the recorded component temperature profile within a first temperature range. The heating power can be limited according to the heating control function of the additional PID controller for temperatures corresponding to the recorded component temperature profile within a further temperature range. Selecting the minimum ensures that none of the limit values / setpoints are exceeded. Alternatively or additionally, a further limitation can be inserted at the end of the minimum selection to protect the heating component. This limitation can correspond to the maximum permissible heating power of the heating component at various operating points.

[0032] This makes it possible to implement component temperature gradient-based control for one or more temperature ranges. For example, this allows for a smooth transition from controlling a heating process to controlling the temperature of an operating state. By stipulating that the heating power of the additional PID controller must be increased by at least the heating power determined by the heating control function of the gradient PID controller, this transition can be made seamless.

[0033] According to a preferred embodiment, the gradient setpoint can be specific to the component of the detected component temperature profile. Preferably, the component can have a permissible heating rate that is lower than that of other components of the fuel cell system. Alternatively or additionally, the gradient setpoint can be specified according to a limit function. Preferably, the limit function can have at least a partially constant profile. Preferably, the limit function can have the detected component temperature profile as an input parameter.

[0034] In this way, the control procedure can be tailored to monitor the heating process of a specific component. Furthermore, the gradient setpoint can be flexibly adjusted to suit the situation. For example, the temperature-dependent strain behavior of a material or multiple materials that are part of a component can be taken into account. For instance, the strain of one material might only be problematic in a specific temperature range, while the strain of a second material becomes problematic when entering a different temperature range. Naturally, the gradient setpoints of different components can also be considered. This allows the control procedure to be adapted with exceptional flexibility to the specific fuel cell system.

[0035] According to a further preferred embodiment, determining the component temperature gradient can include a step in which average temperatures are calculated from the component temperature profile. The average temperatures can preferably be averaged over successive averaging periods of the same or variable length of the component temperature profile. In a further step, the component temperature gradient can be calculated as a change over time from the calculated average temperatures. The average temperatures are available within a change period of the component temperature profile. Preferably, the change period can be an observation time window for the recorded component temperature profile.

[0036] This provides a way to efficiently and accurately determine the component temperature gradient from the component temperature profile.

[0037] For the purposes of the invention, the means can be understood to be, in particular, an arithmetic or geometric mean. The observation time window can be understood, in particular, as a moving time window with which temperature data from the component temperature profile are selected. For example, the duration of the component temperature profile can be defined. Similarly, the change period can also be understood as a moving time window by which it can be specified which of the average temperatures are to be used for calculating the change over time.

[0038] Preferably, the determined component temperature gradient can be limited to an upper limit and / or lower limit.

[0039] This ensures, for example, that irregularities in the temperature data of the component temperature profile do not lead to a dangerous increase in heating power. For instance, measurement inaccuracies or outliers can lead to an inaccurate determination of the component temperature gradient and consequently to an inappropriate increase in heating power.

[0040] According to a preferred embodiment, parameters for determining the component temperature gradient can be determined from tests on the fuel cell system. These parameters can include the observation time window for the component temperature profile, the change period for calculating the component temperature gradient, and / or the length of the averaging periods.

[0041] The component temperature gradient can thus be determined even more precisely using the aforementioned calculation steps. The parameters can depend, in particular, on the settings and configuration of the measurement technology. For example, the measurement rate or accuracy of the measurement technology used can influence the required observation time window or change period. Furthermore, characteristics of the component within the component temperature profile can also affect the parameters. For instance, it may be necessary to capture the signal corresponding to a component temperature profile over a longer observation time window due to measurement noise or fluctuations. Experiments to determine the parameters could involve, for example, a sudden thermal excitation of the fuel cell system or a thermal excitation of the fuel cell system along a predefined curve.

[0042] According to a further preferred embodiment, a control signal for increasing the heating power of a heating device can be output in a further step. This control signal can be used to control an electric and / or catalytic heating device. For example, the control signal can be a pulse-width modulated signal.

[0043] This means that increasing the heating output can be easily implemented for a wide variety of heating devices.

[0044] It can also be advantageous to use the control method according to the invention for cooling a fuel cell system. The control method described above is preferably also used for cooling and / or reducing heating power. The comparison of the setpoint and the actual value determines the sign of the heating power to be increased, which can also be negative. The steps described above then apply accordingly, mutatis mutandis.

[0045] Another aspect of the invention relates to a computer program product. The computer program product includes instructions which, when executed by a computer, cause the computer to perform the steps of one of the aforementioned control methods.

[0046] Another aspect of the invention relates to a control device for monitoring the heating process of a fuel cell system. The control device comprises a detection module for recording at least one component temperature profile of at least one component of the fuel cell system. The control device further comprises a determination module for determining a component temperature gradient relative to the recorded component temperature profile, as well as a comparison module for comparing the determined component temperature gradient with a gradient setpoint. In addition, the control device includes a control module for increasing the heating power of a heating device for heating the component until the determined component temperature gradient reaches the gradient setpoint.

[0047] Preferably, the acquisition module, the investigation module, the comparison module and the control module can be configured to execute the procedure described above.

[0048] According to a further preferred embodiment, the control device can include a sensor device for detecting the component temperature profile.

[0049] The sensor device can preferably be arranged to detect the cathode temperature in the fuel system. Alternatively or additionally, the control device can include a controllable heating device for supplying heat to the component. Preferably, the sensor device and the heating device can be spaced apart from each other.

[0050] Another aspect of the invention relates to a fuel cell system. In particular, the fuel cell system can be a solid oxide fuel cell system. The fuel cell system comprises a fuel cell stack with an anode section and a cathode section, wherein a plurality of fuel cells are arranged in a stacked manner within the fuel cell stack. The anode section has an anode supply section for supplying anode supply gas and an anode discharge section for removing anode exhaust gas. The cathode section has a cathode supply section for supplying cathode supply gas and a cathode discharge section for removing cathode exhaust gas. Furthermore, the fuel cell system comprises the aforementioned control device.

[0051] The aforementioned computer program, control device, and fuel cell system achieve the same technical effects and advantages as those already described for the control procedure. Therefore, reference is made below only to the corresponding explanations.

[0052] Further advantages, features and details of the invention will also become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. Fig. Figure 1 shows a schematic representation of an embodiment of a control method according to the invention. Fig. Figure 2 shows a schematic representation of an embodiment of a control device according to the invention and an embodiment of a fuel cell system.

[0053] Fig. Figure 1 shows an exemplary embodiment of a control method 10 according to the invention. The control method 10 is adapted for controlling a heating process of a fuel cell system 200. The fuel cell system 200 has a component 201, which can, for example, be a fuel cell stack 210. The fuel cell system 200 is in Fig. 1 is only shown schematically, but will be explained with reference to the Fig. 2 will be explained in more detail in one of the following sections.

[0054] In control procedure 10, a component temperature profile KT1 of component 201 is recorded in a data acquisition step 20. Preferably, the component temperature profile KT1 can be recorded for a time-dependent observation window BF.

[0055] From this component temperature profile KT1, a component temperature gradient KTG is then determined in a calculation step 30. A series of processing steps can take place in calculation step 30 to determine the component temperature gradient KTG. For example, in an averaging step 31, average temperatures DT for individual averaging time periods MZA can be calculated from the component temperature profile KT1. Using the average temperatures DT, a change in the average temperatures DT over a change period AZ can then be calculated in a derivation step 32. In a restriction step 33, it can be checked, for example, whether the change in the average temperatures DT over time lies within a permissible range and, if necessary, whether the change should be limited to a permissible value.The component temperature gradient KTG can be determined from the component temperature profile KT1 in the manner described above.

[0056] Preferably, the control procedure 10 can include a parameter determination step 60 in which parameters required for the signal-based acquisition of the component temperature profile KT1 and the numerical determination of the component temperature gradient KTG are identified from a multitude of measured values ​​MW. The measured values ​​MW can be a temperature or other physical quantities of the fuel cell system 200. In parameter determination step 60, for example, the length of the observation period BF for the component temperature profile KT1, the change period AZ, and / or the averaging time intervals MZA can be determined.

[0057] In comparison step 40, the component temperature gradient (CTG) is compared with a gradient setpoint (KGS), also referred to as the component gradient setpoint (KGS). If, for example, the component temperature gradient (CTG) is significantly higher than the gradient setpoint (KGS), a warning can be issued to a user, including the component temperature gradient (CTG) in a notification step 80. However, this is merely an example, and the control procedure 10 can also react to an exceedance of the gradient setpoint (KGS) in other ways, such as by taking measures to reduce the component temperature gradient (CTG).

[0058] In a control step 50, the heating power HL of a heating device 190 is increased to heat component 201 until the determined component temperature gradient KTG reaches the gradient setpoint KGS. For this purpose, control step 50 can include a heating power determination step 51, in which the increase in heating power HL is determined, for example, according to a heating control function HKF. Thus, the increase in heating power HL can be determined from the component temperature gradient KTG and the gradient setpoint KGS using a transfer function of a controller as the heating control function HKF. The heating power HL to be increased in this way can be further adjusted or changed in a selection step 52 with respect to a selection criterion AK.For example, depending on a temperature range limit TBG of the component temperature profile KT1, the heating power HL to be increased can be limited before the increase in heating power HL is carried out. This can be done repeatedly.

[0059] Furthermore, it should be noted that the previously described comparison step 40 can also be part of control step 50 and, in particular, the heating control function HKF. For example, the comparison of the component temperature gradient KTG with the gradient setpoint KGS can be part of the heating control function HKF.

[0060] In an optional output step 70, a control signal KS can be output to increase the heating power HL of the heating device 190. The heating device 190 can be, for example, an electric and / or catalytic heating device. The control signal KS can, for example, be a pulse-width modulated signal for direct control of the heating device 190. Alternatively or additionally, the control signal KS can be used to transmit a fuel quantity or fuel concentration to the heating device 190, which is integrated into the fuel cell system 200.

[0061] Fig. Figure 2 shows an exemplary embodiment of the fuel system 200 according to the invention with a control device 100 according to the invention.

[0062] The control device 100 is designed to control a heating process of a fuel cell system 200.

[0063] The control device 100 has a detection module 120 by means of which the component temperature profiles KT1, KT2, KT3 of various components 201, 202, 203 of the fuel cell system 200 can be detected. This is in Fig. 2 is exemplified by the connection of the detection module 120 with associated sensor devices 180. The sensor device 180 can, for example, be a temperature sensor. As in Fig. As shown in Figure 2, the respective sensor device 180 can be part of the control device 100 or the fuel cell system 200. The acquisition module 120 can, for example, supply a parameter determination module 160 with the measured values ​​in MW, which are, for example, assigned to the component temperature profiles KT1, KT2, and KT3. The parameter determination module 160 can, for example, be used to determine the parameters mentioned in parameter determination step 60.

[0064] The control device 100 further comprises a determination module 130, by means of which the component temperature gradient KTG is determined for the corresponding recorded component temperature profile KT1. For example, the component temperature gradient KTG can also be determined for each or individual recorded component temperature profile KT1, KT2, KT3.

[0065] The control device 100 also includes a comparison module 140 for comparing the determined component temperature gradient KTG with the gradient setpoint KGS. The gradient setpoint KGS can be provided by a setpoint function GWF. The setpoint function GWF can, for example, have one or more system parameters as input parameters.

[0066] The control device 100 also has a control module 150, by means of which the heating power HL of the heating device 190 is increased for heating the component 201 until the determined component temperature gradient KTG reaches the gradient setpoint KGS.

[0067] The control module 150 can include a gradient PID controller GR implementing the heating control function HKF, which determines the required heating power HL from the component temperature gradient KTG and the gradient setpoint KGS. The comparison module 140 can, for example, be part of the gradient PID controller GR, in which the comparison between the component temperature gradient KTG and the gradient setpoint KGS is performed, for example, by subtraction, to determine a deviation from the setpoint. The required heating power HL is continuously summed in this module. This results in a steady increase in the heating power according to the component gradient setpoint.

[0068] Additionally, the control module 150 can include a first supplementary PID controller ZR1 and a second supplementary PID controller ZR2. These can also be part of the heating control function HKF. Of course, it is also conceivable that the control module 150 has further such supplementary PID controllers. Using the supplementary PID controllers ZR1 and ZR2, a heating power limit HL can be determined based on a temperature limit TG, which is specific to one of the other components 202 and 203, respectively.

[0069] Using a selection module 151, a suitable heating power HL to be increased can be selected from the heating powers HL determined in this way, based on the selection criterion AK. For this purpose, a minimum selection section 521 can be included in the selection module 151 to select a minimum from the aforementioned determined heating powers HL to be increased. It is also conceivable to determine the minimum from among several heating powers HL determined by the gradient PID controller GR for other component temperature profiles KT1, KT2, KT3. Alternatively or additionally, the selection module 151 can include a temperature range selection section 522 in which a selection can be made for at least one of the component temperature profiles KT1, KT2, KT3 with respect to the temperature range limit TBG, depending on the temperatures.

[0070] Preferably, the control module 150 can also include a limiting module 152, by means of which impermissible increases in the heating power HL can be limited. This implements a protective function for the heating component. Subsequently, for example, the heating power HL of the heating device 190 can be increased to heat the component 201 until the determined component temperature gradient KTG reaches the gradient setpoint KGS.

[0071] To control the heating device 190, the control device 100 can, for example, have an output module 170. One or more control signals KS can be output via the output module 170. The control signals KS represent, for example, the heating power HL to be increased. Fig. 2. For example, the current of an electric heating device 192 and the rotational speed of a rotor 191 can be adjusted by the control signals KS. The rotor 191 and the heating device 192 are components of the heating device 190, which is designed, for example, as a hot air device. The heating device 190 can be part of the control device 100 or also part of the fuel system 200. Preferably, the heating device 190 can be provided at a distance from the sensor device 180 in order to avoid interference and over-regulation.

[0072] The in Fig. The fuel cell system 200 shown in Figure 2 has the fuel cell stack 210, which has an anode section 212 and a cathode section 211. The cathode section 211 has component 201. The anode section 212 has further components 202 and 203. The sensor devices 180 are in Fig.2 as distributed in the fuel cell stack 210 and arranged adjacent to the respective components 201, 202, 203. In this way, for example, a cathode temperature can be detected by the sensor device 180.

[0073] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention. Reference symbol list 10 Control procedures 20 Recording step 30 Investigation Step 31st averaging step 32nd derivation step 33 Restriction step 40 Comparison step 50 Control Step 51 Heating output determination step 52 Selection step 60 Parameter determination step 70 Output step 80 reporting step 100 Control device 120 Data acquisition module 130 Investigation Module 140 Comparison module 150 Control module 151 Selection module 521 Minimum Choice Section 522 Temperature range selection section 152 Limiting module 160 Parameter determination module 170 Output module 180 Sensor device 190 Heating device 191 Rotor 192 electric heater 200 fuel cell systems 201 Component 202, 203 other components 210 fuel cell stacks 211 Cathode section 212 Anode section AK selection criterion AZ Change period BF observation period, observation window DT Average temperatures MZA averaging periods HKF heating control function GR Gradient PID Controller ZR1 first additional PID controller ZR2 second additional PID controller GWF limit function TG temperature limit TBG temperature range limit KT1 Component Temperature Profile KT2, KT3 further component temperature profiles KTG component temperature gradient KGSKGS HL heating output KS control signal MW measured values

Claims

[1] Control procedure (10) for controlling a heating process of a fuel cell system (200), comprising the following steps: - Recording at least one component temperature profile (KT1, KT2, KT3) of at least one component (201, 202, 203) of the fuel cell system (200), characterized by - Determining a component temperature gradient (CTG) for the recorded component temperature profile (CT1, CT2, CT3), - Comparison of the determined component temperature gradient (CTG) with a gradient setpoint (CTS), and - Increasing the heating power (HL) of a heating device (190) for heating the component (201, 202, 203) until the determined component temperature gradient (KTG) reaches the gradient setpoint (KGS). [2] Control method (10) according to claim 1, characterized by Increase in heating output (HL) after a heating control function (HKF), wherein preferably the heating output (HL) is limited between two limit values ​​according to the heating control function (HKF), and / or where the heating power (HL) is preferably increased at least partially monotonically continuously and / or monotonically intermittently according to the heating control function (HKF). [3] Control method (10) according to claim 2, characterized in that the heating control function (HKF) has a gradient PID controller (GR) which has the determined component temperature gradient (KTG) and the gradient setpoint (KGS) as input parameters. [4] Control method (10) according to claim 3, characterized in that the heating control function (HKF) is further based on the recorded component temperature profile (KT1, KT2, KT3) of at least one other component (201, 202, 203) of the fuel cell system (200) as an input parameter, wherein the heating control function (HKF) has at least one additional PID controller (ZR1, ZR2) to limit the heating power (HL) depending on the further detected component temperature profile (KT1, KT2, KT3) and preferably on a temperature limit value (TG) specific for the further component (201, 202, 203), and wherein the heating control function (HKF) further includes a selection criterion (AK) for selecting between the heating power (HL) to be increased according to the heating control function (HKF) of the gradient PID controller (GR) and the heating power (HL) to be limited according to the heating control function (HKF) of the additional PID controller (ZR1, ZR2). [5] Control method (10) according to claim 4, characterized in that the selection criterion (AK) is a minimum of the heating power (HL) to be increased according to the heating control function (HKF) of the gradient PID controller (GR) and the heating power (HL) to be limited according to the heating control function (HKF) of the additional PID controller (ZR1, ZR2). [6] Control method (10) according to claim 4 or claim 5, characterized in that the selection criterion (SC) is based on a comparison of at least one of the recorded component temperature profiles (KT1, KT2, KT3) with a temperature range limit (TBG), wherein the heating power (HL) is increased according to the heating control function (HKF) of the gradient PID controller (GR) for temperatures corresponding to the detected component temperature profiles (KT1, KT2, KT3) within a first temperature range, and where the heating power (HL) is limited according to the heating control function (HKF) of the additional PID controller (ZR1, ZR2) for temperatures of the corresponding component temperature profiles (KT1, KT2, KT3) within a further temperature range. [7] Control method (10) according to claim 6, characterized in that the heating power (HL) for the further temperature range is increased at least to the heating power (HL) to be increased according to the heating control function (HKF) of the gradient PID controller (GR). [8] Control method (10) according to any of the preceding claims, characterized by the fact that the gradient setpoint (KGS) is specific for component (201, 202, 203) of the recorded component temperature profile (KT1, KT2, KT3), and / or The gradient setpoint (KGS) is specified according to a setpoint function, wherein preferably the setpoint function has at least a partially constant profile and / or system parameters as input. [9] Control method (10) according to any of the preceding claims, characterized by the fact that the determination of the component temperature gradient (CTG) exhibits: - Calculating average temperatures (DT) from the component temperature profile (KT1, KT2, KT3), which are averaged over preferably successive averaging time periods (MZA) of the same or variable length of the component temperature profile (KT1, KT2, KT3), - Calculating the component temperature gradient (CTG) as a temporal change from the calculated average temperatures (DT) which are present within a change period (AZ) of the component temperature profile (KT1, KT2, KT3), wherein preferably the change period is an observation time window (BF) for the recorded component temperature profile (KT1, KT2, KT3), and - preferably limiting the calculated component temperature gradient (CTG) to an upper limit and / or lower limit. [10] Control method (10) according to claim 9, characterized by a determination of parameters for determining the component temperature gradient (CTG) from experiments on the fuel cell system (200), where the parameters include the observation time window (BF) for component temperature profile (KT1, KT2, KT3), the change period (AZ) for calculating the component temperature gradient (KTG) and the length of the averaging time periods (MZA). [11] Control method (10) according to any of the preceding claims, characterized by Output of a control signal (KS) to increase the heating power (HL) of a heating device (190), wherein the control signal (KS) is provided for controlling an electrical and / or catalytic heating device, wherein preferably the control signal (KS) is a pulse width modulated signal or another representative quantity for a heating power. [12] Computer program product, characterized by Commands which, when executed by a computer, cause it to perform the steps of a control procedure (10) having features of any one of claims 1 to 11. [13] Control device (100) for controlling a heating process of a fuel cell system (200), comprising - a recording module (120) for recording at least one component temperature profile (KT1, KT2, KT3) of at least one component (201, 202, 203) of the fuel cell system (200), characterized by - a determination module (130) for determining a component temperature gradient (CTG) for the recorded component temperature profile (CT1, CT2, CT3), - a comparison module (140) for comparing the determined component temperature gradient (CTG) with a gradient setpoint (CTS), and - a control module (150) for increasing the heating power (HL) of a heating device (190) for heating the component (201, 202, 203) until the determined component temperature gradient (KTG) reaches the gradient setpoint (KGS), wherein the detection module (120), the determination module (130), the comparison module (140) and the control module (150) are configured for an embodiment of a method (10) with the features of one of claims 1 to 11. [14] Control device (100) according to claim 13, characterized by - a sensor device (180) for detecting the component temperature profile (KT1, KT2, KT3), wherein the sensor device (180) is preferably arranged to detect a cathode temperature, and / or - a controllable heating device (190) for supplying a heating power (HL) to the component (201, 202, 203), wherein the sensor device (180), if present, is preferably provided spaced apart from the heating device (190). [15] Fuel cell system (200), in particular solid oxide fuel cell system, comprising - a fuel cell stack (210) with an anode section (212) and with a cathode section (211), wherein a plurality of fuel cells are arranged in a stacked manner in the fuel cell stack (210), wherein the anode section (212) has an anode supply section for supplying anode supply gas and an anode discharge section for discharging anode exhaust gas, and wherein the cathode section (211) has a cathode supply section for supplying cathode supply gas and a cathode discharge section for removing cathode exhaust gas, characterized by - a control device (100) according to one of claims 13 and 14.

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