Method of controlling power system of fuel cell electric vehicle

Abstract

The present disclosure relates to a computer-implemented method of controlling a power system of a fuel cell electric vehicle (FCEV) including a fuel cell and an energy storage system electrically connected to each other. An upcoming location is determined when the power system will assume a low load mode of operation, and the power system is controlled based on the power distribution scheme to reach the upcoming location at a state of charge level of the energy storage system below a predetermined threshold level, when the power system assumes a low load mode of operation at an upcoming location, the power system is controlled to feed power at least to the consumer.

Description

Technical Field

[0001] The present invention relates to an electric power system comprising an energy storage system and a fuel cell. In particular, the present invention relates to a method of controlling such an electric power system. The present invention is applicable to so-called fuel cell electric vehicles (FCEVs), in particular medium and heavy-duty FCEVs. Although the present invention will be described with respect to a heavy-duty FCEV in the form of a truck, the present disclosure is not limited to this particular vehicle but may also be used for other FCEVs. Background Art

[0002] Electric propulsion of passenger cars is becoming a common solution to reduce the environmental impact of vehicles. Heavy vehicles such as trucks are also evolving to be able to provide electric propulsion. An electric propulsion system includes one or more electric machines that are operable to generate propulsion torque at one or more wheels of the vehicle.

[0003] However, heavy vehicles require batteries with large energy capacity to feed electric motors with electricity in order to provide a desired vehicle operating range. Therefore, the capacity of the battery is a limiting factor for heavy vehicles.

[0004] The use of fuel cells to generate electricity during the operation of the vehicle is one method for increasing the operating range of heavy vehicles. The electricity generated by the fuel cell can be fed to a battery / multiple batteries, or directly fed to a motor that propels the vehicle. In order to reduce the degradation of the fuel cell, it is preferably not to shut down the fuel cell during the operation of the FCEV. However, during certain operating conditions, the energy storage system may not be able to receive the electricity generated by the fuel cell, for example because the state of charge level of the energy storage system is above a certain limit. In this case, the electricity generated by the fuel cell must be dissipated, or the fuel cell must be shut down. Dissipating electrical energy is not efficient, and as mentioned above, it is not desirable to shut down the fuel cell. Therefore, a solution that can avoid both of these situations is needed. Summary of the invention

[0005] Therefore, an object of the present disclosure is to alleviate the above-mentioned drawbacks.

[0006] According to a first aspect, there is provided a computer-implemented method of controlling an electrical system of a fuel cell electric vehicle (FCEV), the electrical system comprising: a fuel cell and an energy storage system electrically connected to each other, wherein the FCEV comprises a traction electric motor connected to the electrical system, the electrical system being configured to feed electrical power to the traction electric motor at a propulsion power level range during propulsion and to receive electrical power generated by the traction electric motor during braking, the electrical system being operable to assume a low-load operating mode in which electrical power is fed to an energy consumer of the FCEV at a power level below the propulsion power level range; and a processing circuit operable coupled to the energy storage system, the method comprising: determining, by the processing circuit, an upcoming location where the electric power system will assume the low-load operating mode; determining, by the processing circuit, a current state of charge level of the energy storage system; determining, by the processing circuit, a power distribution scheme between the electric power system and the traction electric motor to reach the upcoming location at a state of charge level of the energy storage system below a predetermined threshold level; controlling, by the processing circuit, the electric power system based on the power distribution scheme; and controlling, by the processing circuit, the electric power system to feed power to at least the energy consumer when the electric power system assumes the low-load operating mode at the upcoming location.

[0007] An electrical consumer is to be understood as a component or structure of a FCEV that consumes electrical power from the electrical power system. For example, an electrical consumer may be a vehicle headlight, an infotainment system of the vehicle or even a control unit of the FCEV that may be operated by electrical power. According to a preferred example embodiment, an electrical consumer may be a vehicle auxiliary system electrically connected to the electrical power system. A vehicle auxiliary device may be, for example, a crane that may be operated by an operator of the vehicle to load or unload materials onto or from the FCEV.

[0008] The location at which the power system will adopt the low-load operating mode can be determined based on, for example, map data, statistics from previous usage of the vehicle or other vehicles (i.e., historical data). Therefore, the upcoming location can be a predetermined upcoming location. Therefore, and according to an example embodiment, the method may also include determining, by the processing circuit, the upcoming location at which the power system will adopt the low-load operating mode based on the map data. The historical data may be received from, for example, artificial intelligence. In addition, the historical data may be received from a background or cloud storage memory, etc., or from a memory forming part of a control unit arranged in the vehicle. Therefore, and according to an example embodiment, the method may also include determining, by the processing circuit, the upcoming location at which the power system will adopt the low-load operating mode based on previous vehicle usage.

[0009] Thus, the upcoming position is a position when the power system assumes a low-load operating mode and feeds power to the energy consumers. According to a non-limiting example, the upcoming position may be a traffic jam in front of the vehicle. In this case, the power system feeds power to power electronics that control, for example, the operation of the vehicle headlights or other electrical consumers when the vehicle is stationary in a queue in a traffic jam. According to another non-limiting example, the upcoming position may be a loading / unloading position when the vehicle is stationary and is loaded / unloaded by an energy consumer in the form of the above-mentioned vehicle auxiliary equipment.

[0010] Furthermore, and as mentioned above, the low load operating mode is therefore a mode when the power level is below the propulsion level range. Thus, when the low load operating mode is assumed, the power system is preferably unable to feed sufficient power to the traction electric motor to propel the FCEV. The power fed to the energy consumer during the low load operating mode may be a range, i.e., not necessarily a fixed power level.

[0011] In addition, the processing circuit preferably determines the topology of the upcoming road path for reaching the upcoming location. Therefore, the energy consumption for operating the FCEV along the upcoming road path can be determined. Accordingly, an alternative to reaching the upcoming location at a state of charge level below a predetermined threshold level is given. Therefore, and according to an example embodiment, the power distribution scheme is based on the topology of the upcoming road path. In the present context, the road topology should be understood as the variation of uphill and downhill of the upcoming road path. Therefore, the upcoming road path may include one or more uphills with various angles and lengths, and one or more downhills with various angles and lengths. The power distribution scheme should be understood as the determined energy consumption of the power system along the road path until the upcoming location is reached. Therefore, the power distribution scheme preferably includes feeding power from the power system to the traction electric motor at different rates during propulsion, and charging the energy storage system at different rates by feeding the energy storage system with power generated by the traction electric motor during braking. Therefore, and according to an example embodiment, the method may also include determining, by the processing circuit, the electrical energy consumption of the traction electric motor to reach the upcoming location; wherein the power distribution scheme is based on the determined electrical energy consumption. The power distribution scheme also preferably includes the level of power that the fuel cell will produce prior to arriving at the upcoming location.

[0012] The present invention is based on the recognition that by determining a position at which the power system is about to adopt a low load mode of operation, the power system can be controlled in advance of reaching that position so that when the upcoming position is eventually reached, the state of charge level of the energy storage system is below a predetermined threshold level. The advantage is that when the position is reached, the state of charge level is at such a low level that the fuel cell can be operated to generate electricity, and any excess electricity not consumed by the energy consumer can be fed to the energy storage system. Therefore, the fuel cell does not need to be shut down or electricity dissipated. Therefore, the degradation rate of the fuel cell is reduced and electrical energy is not wasted.

[0013] According to an example embodiment, the method may also include: determining, by the processing circuit, an expected state of charge level of the energy storage system when the low-load operating mode is terminated; determining, by the processing circuit, an energy consumption level of the energy consumer during the low-load operating mode; and determining, by the processing circuit, a charge level of the energy storage system by the fuel cell during the low-load operating mode; wherein the predetermined threshold level of the energy storage system when the upcoming location is reached is based on the expected state of charge level and a difference between the charge level of the energy storage system and the energy consumption level of the energy consumer.

[0014] Thus, the predetermined threshold level of the energy storage system is based on, for example, the subsequent use of the FCEV when the low-load operating mode ends. Hereby, it can be guaranteed that the FCEV will also be able to manage future missions, i.e., the power system will be able to operate the traction electric motor in the desired manner. Preferably, and according to an example embodiment, the desired state of charge level of the energy storage system may be based on topological data of a road path that can be operated by the FCEV after the low-load operating mode ends.

[0015] In this context, road topology should be understood as the variation of uphill and downhill slopes of the upcoming road path. Thus, the upcoming road path may include one or more uphill slopes with various angles and lengths, and one or more downhill slopes with various angles and lengths.

[0016] According to an exemplary embodiment, when the low load operation mode is adopted, the power system can be controlled to feed power from the fuel cell to the energy consumer. Accordingly, the energy consumer mainly consumes the electrical energy from the fuel cell. As indicated above, the excess electrical energy is preferably fed to the energy storage system.

[0017] According to an example embodiment, the determined electrical energy consumption may be based on planned operating information of a traction electric motor for propelling the FCEV from the current location to the upcoming location. From this, a level of power consumed by the traction electric motor during propulsion and a level of power generated by the traction electric motor during braking may be determined. Alternatively or additionally, and according to an example embodiment, the method may further include: determining, by the processing circuit, a road topology of a road path from the current location to the upcoming location to be operated by the FCEV; and wherein the determined electrical energy consumption is based on a road topology from the current location to the upcoming location.

[0018] According to an example embodiment, the method may further include: dividing, by the processing circuit, an upcoming road path from the current location to the upcoming location into a plurality of road path portions, each road path portion being associated with separate road topology data; wherein the electrical energy consumption of the traction electric motor is determined for each road path portion.

[0019] By dividing the road path into a plurality of road path portions, the computational effort for estimating the power consumption along the entire road trip is reduced compared to estimating the power consumption along the entire road path to the upcoming location. Preferably, and according to an example embodiment, the method may further include: setting, by the processing circuit, an expected state of charge level of the energy storage system at the upcoming location, the expected state of charge level being lower than the predetermined threshold level; determining, by the processing circuit, an expected power capacity of the power system for each road path portion to reach the terminal location at the expected state of charge level of the energy storage system, the expected power capacity of each road path portion being based on its next upcoming road path portion; and controlling, by the processing circuit, the power system based on the expected power capacity of each road path portion. Thus, a reverse calculation is performed based on the expected state of charge level at the terminal location of the upcoming road path. Therefore, the FCEV should not only be able to operate without depleting the energy storage system, but also be able to reach the final location at the expected state of charge. If the processing circuit determines that this cannot be achieved by controlling the fuel cell to adopt a cruise mode, the fuel cell should be controlled to adopt a power mode throughout the upcoming road path (i.e., for each road path portion) until the terminal location is reached. Therefore, the end position corresponds to the upcoming position.

[0020] According to an example embodiment, the method may further comprise controlling, by the processing circuit, the power system to feed power only from the energy storage system to the traction electric motor during at least a portion of the driving distance from the current location to the upcoming location when the current state of charge level of the energy storage system is above an upper threshold level. It will therefore be appreciated that the fuel cell is still in operation, i.e. not shut down, and feeds power to the energy storage system. Since the traction electric motor consumes more electrical energy than is generated by the fuel cell, it is ensured that the energy storage system will be at least partially depleted of electrical energy when the upcoming location is reached. Furthermore, when the state of charge level is above the upper threshold level, it will be necessary to feed power only from the energy storage system to the traction electric motor in order to reach the upcoming location at a state of charge level below a predetermined threshold level. Therefore, in this example, the predetermined threshold level is a lower predetermined threshold level.

[0021] According to an example embodiment, the fuel cell is operable to assume an idle mode in which the fuel cell generates electricity at a first power level and a power mode in which the fuel cell generates electricity at a second power level that is higher than the first power level.

[0022] The idle mode should be understood as the "sweet spot" of the fuel cell, i.e., the fuel cell is operated to produce a power level at which the fuel degradation rate is kept to a minimum. When the idle mode is adopted, the fuel cell produces power somewhere in the middle of its power range (i.e., medium power). Therefore, the fuel cell should preferably adopt the idle mode as much as possible. Preferably, and according to an example embodiment, when the power system adopts the low-load operating mode, the fuel cell can adopt the idle mode. Therefore, the fuel cell is also operated in its optimal operating mode when adopting the low-load operating mode.

[0023] According to an example embodiment, the fuel cell may assume the idle mode when the power system is controlled to feed power from the energy storage system to the traction electric motor to reach the upcoming location. The advantage is that the fuel cell operates at its optimum state and the power consumed by the traction electric motor to reach the upcoming location is received from the energy storage system.

[0024] According to an example embodiment, when the power system assumes the low load operation mode, the FCEV may be placed in a stationary operation mode.

[0025] The stationary operating mode should be understood as a mode when the FCEV is stationary, preferably with the parking brake engaged. Thus, during the stationary operating mode, the traction electric motor does not propel the vehicle.

[0026] According to an example embodiment, the energy consumer may be a vehicle auxiliary system electrically connected to the electrical system.

[0027] The vehicle auxiliary equipment can be, for example, a crane located behind the vehicle cab. Another vehicle auxiliary equipment can be a winch or the like.

[0028] According to an example embodiment, when the power system assumes the low load operation mode, the energy consumer may consume power at a power level lower than the power level generated by the fuel cell, wherein when the power system assumes the low load operation mode, the difference between the power generated by the fuel cell and the power consumed by the energy consumer is fed from the fuel cell to the energy storage system. Since the state of charge level of the energy storage system is controlled to be below a predetermined threshold level upon arrival at the upcoming location, the energy storage system will be able to receive the power generated by the fuel cell, and the electrical energy does not need to be dissipated and wasted.

[0029] According to a second aspect, there is provided an electric power system of a fuel cell electric vehicle (FCEV), the electric power system comprising: a fuel cell; an energy storage system electrically connected to the fuel cell; and a control unit connected to the fuel cell, the electric power system being configured to feed electric power to a traction electric motor of the FCEV during propulsion within a propulsion power level range and to adopt a low-load operation mode, wherein the electric power system feeds electric power to electrical consumers of the FCEV at a power level lower than the propulsion power level range, the control unit being configured to: determine an upcoming location where the electric power system will adopt the low-load operation mode; determine a current state of charge level of the energy storage system; determine a power distribution scheme between the electric power system and the traction electric motor to arrive at the upcoming location at a state of charge level of the energy storage system lower than a predetermined threshold level; control the electric power system based on the power distribution scheme; and control the electric power system to feed electric power to at least the energy consumer when the electric power system adopts the low-load operation mode at the upcoming location.

[0030] The control unit may include a microprocessor, a microcontroller, a programmable digital signal processor or another programmable device. The control unit may also include or alternatively include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device or a digital signal processor. In the case where the control unit includes a programmable device (such as a microprocessor, a microcontroller or a programmable digital signal processor mentioned above), the processor may also include a computer executable code that controls the operation of the programmable device.

[0031] The effects and features of the second aspect are largely similar to those described above with respect to the first aspect.

[0032] According to a third aspect, there is provided a fuel cell electric vehicle (FCEV) comprising the power system according to the second aspect.

[0033] According to a third aspect, a vehicle is provided, the vehicle comprising the system according to the second aspect.

[0034] According to a fourth aspect, there is provided a computer program comprising program code means for performing the method of any one of the embodiments described above in relation to the first aspect when the program is run on a computer.

[0035] According to a fifth aspect, there is provided a non-transitory computer readable medium carrying a computer program, the computer program comprising program code for executing any one of the methods in the embodiments of the first aspect above when the program product is run on a computer.

[0036] According to a sixth aspect, there is provided a control unit for controlling an auxiliary system of a transport vehicle, the control unit being configured to execute the method of any one of the embodiments described above with respect to the first aspect.

[0037] Effects and features of the third, fourth, fifth and sixth aspects are largely similar to those described above with respect to the first aspect.

[0038] Further features and advantages of the present disclosure will become apparent when studying the appended claims and the following description.Those skilled in the art realize that different features of the present disclosure can be combined to create examples other than those described in the following, without departing from the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and further objects, features and advantages of the present disclosure will be better understood through the following illustrative and non-limiting detailed description of exemplary examples of the present disclosure, in which:

[0040] Figure 1 is a side view of a transport vehicle in the form of a truck according to an example,

[0041] Figure 2 illustrates a vehicle operating at a road path to reach an upcoming location according to an example embodiment,

[0042] Figure 3 shows a vehicle operating at a road path to reach an upcoming location according to another example embodiment,

[0043] Figure 4 is a schematic diagram of a road path operable by a FCEV according to an example embodiment;

[0044] Figure 5 is a schematic diagram of a power system of a FCEV according to an example embodiment; and

[0045] Figure 6 is a flowchart of a method of controlling a power system according to an exemplary embodiment. DETAILED DESCRIPTION

[0046] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which illustrative examples are shown. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided for the sake of thoroughness and completeness. Throughout this specification, like reference numerals refer to like elements.

[0047] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "a kind of" and "the" are intended to also include plural forms. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should also be understood that the terms "comprises", "comprising", "includes" and / or "including" are used herein to clearly indicate the presence of the features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0048] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0049] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that these terms and those discussed above are intended to cover different device orientations in addition to the orientations depicted in the figures. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or directly coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0050] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that, unless otherwise clearly defined herein, the terms used herein should be interpreted as meanings consistent with their meanings in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0051] Specific reference Figure 1 , depicts a fuel cell electric vehicle (FCEV) 10 in the form of a truck. The FCEV 10 will hereinafter be referred to only as a vehicle, and comprises a traction electric motor 101 for propelling the wheels of the vehicle. In an exemplary embodiment, the traction electric motor 101 is arranged in the form of an electric machine. The traction electric motor 101 is arranged to receive power from an electric power system 102 during propulsion, and to feed power generated by the electric machine 101 during braking to an energy storage system 104 of the electric power system. The energy storage system 104 is preferably a high voltage battery of the vehicle 10. From the following disclosure (particularly in conjunction with Figure 5 ) It will be apparent that the power system 102 also includes a fuel cell 106 electrically connected to the energy storage system 104. The fuel cell 106 is configured to generate electricity when receiving hydrogen fuel and oxygen.

[0052] The vehicle 10 also includes a control unit 114 that is connected to the power system 102 for controlling its operation. The control unit 114 may include a microprocessor, a microcontroller, a programmable digital signal processor, or another programmable device. The control unit may also include or alternatively include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. In the case where the control unit 114 includes a programmable device (such as a microprocessor, a microcontroller, or a programmable digital signal processor mentioned above), the processor may also include computer executable code that controls the operation of the programmable device.

[0053] Furthermore, the vehicle 10 includes a plurality of energy consumers 110, 110', 110". Energy consumers 110, 110', 110" should be understood as components or structures of the vehicle 10 that receive electrical energy from the electrical system for use in their operation. Figure 1In the diagram, the electrical consumers 110, 110', 110" are illustrated as a vehicle headlight system 110, an infotainment system 110' arranged in a cab 108 of the vehicle 10, and a vehicle auxiliary device 110" in the form of a crane. In the latter example, the vehicle auxiliary device 110" preferably includes an electric motor 120 for operating the crane. Each of these energy consumers is electrically connected to the power system 102 and can be controlled by a control unit 114. Obviously, the vehicle 10 includes a variety of other energy consumers, but for the sake of simplicity and understanding of the reader, they are not described here.

[0054] During propulsion of the vehicle 10, the fuel cell 106 generates electricity, which is fed to the energy storage system 104, thereby charging the energy storage system 104. The energy generated by the fuel cell 106 can also be fed directly to the traction electric motor 101 during propulsion. During propulsion, electricity is also preferably fed from the energy storage system 104 to the traction electric motor 101. Therefore, when the vehicle 10 is propelled, the energy storage system 10 steadily depletes the electrical energy consumed by the traction electric motor 101.

[0055] In order to reduce the degradation of the fuel cell 106, the fuel cell 106 should preferably not be operated in a power mode, nor should it be shut down. Instead, the fuel cell 106 should preferably be operated in an idle mode in order to reduce its performance degradation. In the power mode, the fuel cell 106 generates electricity at a relatively high level, while in the idle mode, the fuel cell 106 generates electricity at a relatively medium level. When operating the vehicle 10 and reaching a position where the vehicle is stationary, that is, when the traction electric motor is turned off and no electricity is consumed from the power system 102, the fuel cell 106 should preferably not be shut down. In these cases, the power system 102 is operable to adopt a low-load operating mode, in which electricity is fed from the power system 102 to at least one of the above-mentioned energy consumers. When the power system 102 adopts the low-load operating mode, the power system feeds electricity to the energy consumer at a power level lower than the propulsion power level range fed to the traction electric motor 101 during propulsion.

[0056] However, if the state of charge level of the energy storage system 104 is above a predetermined threshold level when the vehicle 10 is stationary and power is being fed to the energy consumers 110, 110', 110", any excess power not consumed by the energy consumers 110, 110', 110" may not be absorbed by the energy storage system 104 because the energy storage system 104 may be "full". Accordingly, the fuel cell 106 may need to be shut down or excess power generated by the fuel cell 106 may need to be dissipated. Various operating scenarios will be described below in order to arrive at an upcoming location where the power system will assume a low load operating mode without shutting down the fuel cell 106 or dissipating valuable power. Therefore, reference will now be made to Figure 2 and Figure 3 .

[0057] First turn Figure 2 , which shows a vehicle 10 operating at a road 202 to reach an upcoming location 204 where a crane will load material 206 onto the vehicle 10. Figure 2 , the upcoming location 204 will also be referred to as the loading location 204. When the vehicle 10 reaches the upcoming location 204, the traction electric motor 101 will be turned off, and the vehicle auxiliary equipment 110" (i.e., the crane) will consume electrical energy from the power system 102 during loading. Specifically, when the vehicle 10 assumes a stationary operating mode at the upcoming location 204, the electric motor 120 of the crane will consume electrical energy. It should be readily understood that the distance 210 from the current location to the upcoming location 204 is only schematically shown, and the following description is for distances significantly greater than Figure 2 The distances depicted in are of course also valid.

[0058] During operation, and before vehicle 10 reaches upcoming location 204 , processing circuitry of control unit 114 determines that vehicle 10 is approaching location 204 to operate a crane to load material 206 onto the vehicle, i.e., power system 102 will assume a low load operating mode at that location 204 .

[0059] When the vehicle 10 is at the current position, i.e., at a distance 210 from the loading position 204, the processing circuit determines the current state of charge level of the energy storage system 104. Based on the current state of charge level, the processing circuit determines a power distribution scheme between the power system 102 and the traction electric motor so as to reach the loading position 204 at a state of charge level below the predetermined threshold level. Therefore, based on the predicted energy consumption of the traction electric motor 101 when the vehicle 10 is operated to travel the distance 210 to reach the loading position, a suitable power distribution scheme can be determined. Therefore, the power distribution scheme should ensure that the vehicle 10 will complete its mission to reach the loading position 204, but once the loading position is reached, the state of charge level should be below the predetermined threshold level. The power distribution scheme can take into account the road topology, where the energy storage system 104 can be charged from time to time when the traction electric motor is operated to generate electricity during braking. In addition, when the travel distance 210 reaches the loading position 204, although the fuel cell 106 may potentially be operated in a power mode from time to time (if required to reach the loading position), the fuel cell 106 should preferably be operated in an idle mode as much as possible. However, for at least a portion of the driving distance from the current location to the upcoming location, particularly when the current state of charge level of the energy storage system is above the upper threshold level, the power system 102 is controlled to feed power only from the energy storage system 104 to the traction electric motor 101 .

[0060] The processing circuitry may determine the loading location 204 based on previous vehicle usage. Specifically, the processing circuitry may know from previous operations that the vehicle 10 will soon reach the loading location 204. The processing circuitry may also receive the location 204 from map data such as, for example, GPS.

[0061] Therefore, the power system 102 is controlled to operate according to the power distribution scheme from the current location to the loading location 204 , whereby the state of charge level of the energy storage system 104 will be below the predetermined threshold level.

[0062] The predetermined threshold level of the energy storage system 104 upon arrival at the upcoming location 204 may be based on a desired state of charge level of the energy storage system 104 after the low load operating mode ends. Specifically, it may be desirable for the energy storage system 104 to have a sufficient state of charge level to operate the vehicle 10 at the roadway 240 after loading the material 206. Therefore, the desired state of charge level of the energy storage system 104 is preferably based on the topological data of the road path 240 operable by the vehicle 10 after the low-load operating mode ends (i.e., after the crane 110" has loaded the material 206 onto the vehicle 10 and the vehicle is ready to perform its next mission). Therefore, the topological data can be used as an indicator of the power distribution scheme between the power system 102 and the traction electric motor 101 when operating the subsequent road path 240. In other words, the processing circuit can determine the power level fed from the energy storage system 104 to the traction electric motor 101 at the road path operable after loading the material 206 during propulsion, or the power level fed from the traction electric motor 101 to the energy storage system 104 at the road path operable after loading the material 206 during braking.

[0063] The processing circuitry may also determine the energy consumption level of the energy consumers during the low-load operating mode. Thus, the processing circuitry determines how much energy is required to operate the crane while loading the material 206. The processing circuitry may also determine the charge level of the energy storage system 104 by the fuel cell 106 during the low-load operating mode. Accordingly, the predetermined threshold level of the energy storage system 104 upon reaching the upcoming location (i.e., the loading location 204 of the material) may be based on the desired state of charge level at the end of the low-load operating mode and the difference between the charge level of the energy storage system and the energy consumption level of the energy consumers. Thus, the predetermined threshold level is based on the energy level required to subsequently operate the vehicle when the material 206 has been loaded onto the vehicle, and the charge level of the energy storage system 104 while loading the material 206.

[0064] When the vehicle 10 reaches the loading position 204, the power system 102 is controlled to feed power to the crane electric motor 120. Preferably, when the vehicle reaches the loading position and the power system assumes a low-load operation mode, the fuel cell 106 is controlled to assume an idle mode. In addition, the power system 102 is also preferably controlled to feed power from the fuel cell 106 to the electric motor 120 of the crane.

[0065] When the power system is in a low-load operating mode, the electric motor 120 of the crane may consume a lower level of power than the power level generated by the fuel cell. In other words, the fuel cell 106 will generate more power than the electric motor 120 of the crane when in an idle mode. Since the state of charge level of the energy storage system 104 is below the predetermined threshold level, the difference between the power generated by the fuel cell and the power consumed by the energy consumer may be fed from the fuel cell to the energy storage system accordingly. When loading the material 206 onto the vehicle 10, no power dissipation will be required, and the fuel cell 106 does not need to be shut down.

[0066] Reference now Figure 3 , which shows that the control method of the power system 102 is the same as that described above Figure 2 Another similar situation. Figure 3 In the example of , the upcoming location 304 is a location along the road where a platoon has been formed, and the vehicle 10 will be arranged in a stationary operating mode, while the power system 102 will adopt a low-load operating mode. When arriving at the platoon, the power system 102 will feed power to, for example, the vehicle headlights 110, the infotainment system 110', etc. Therefore, these energy consumers will require power for their operation.

[0067] When the vehicle is located at a certain distance 310 from the platoon formation, the processing circuit may receive a signal indicating an upcoming stationary operating mode from, for example, a GPS system, an upper control system, etc. The processing circuit may accordingly proceed as described above with respect to Figure 2 The power allocation scheme is determined in a similar manner as described in the example of , and the power system is controlled accordingly. Once the queue formation is reached, the power system 102 feeds power to the energy consumer, and the excess power generated by the fuel cell 106 in the idle mode is fed from the fuel cell 106 to the energy storage system 104.

[0068] So it should be easy to understand. Figure 3 In the exemplary embodiment of the present invention, the control method of the power system 102 is similar to Figure 2 The control method of the power system in the exemplary embodiment is the same.

[0069] Reference now Figure 4 , Figure 44 is a schematic diagram of an upcoming road path 402 operable by vehicle 10 according to an exemplary embodiment. Vehicle 10 is illustrated as being operable between a current location 403 and an upcoming location 404 when power system 102 is operable to assume a low load operating mode. Before vehicle 10 leaves current location 403, processing circuitry divides upcoming road path 402 into a plurality of road path portions 406. Thus, the sum of all road path portions 406 corresponds to the length of upcoming road path 402. Each of the road path portions is associated with separate road topology data. From Figure 4 As can be seen in the figure, the first road path portion 408, the second road path portion 410 and the fourth road path portion 414 are uphill, where the power system 102 will feed power to the traction electric motor 101 to operate these portions, while the third road path portion 412, the fifth road path portion 416 and the sixth road path portion 418 are mainly downhill, where the energy storage system 104 will receive power from the traction electric motor 101 during braking. The processing circuit can therefore determine the electrical energy consumption of the traction electric motor for each road path portion 406.

[0070] The processing circuitry may preferably set an expected state of charge level for the energy storage system at the upcoming location 404. In order to operate the power system 102 to assume a low load operation mode at the upcoming location 404, the expected state of charge level should be below a predetermined threshold level. The processing circuitry also determines an expected electrical energy capacity of the power system for each road path portion to arrive at the terminal location at the expected state of charge level of the energy storage system, whereby the expected electrical energy capacity of each road path portion is based on its next upcoming road path portion. In other words, after the expected state of charge level at the upcoming location 404 has been determined, the expected electrical energy capacity of the power system 102 for the sixth road path portion 418 is determined. From this, the expected state of charge level at the starting point 419 of the sixth road path portion 418 can be determined. Thereafter, based on the expected state of charge level at the starting point 419 of the sixth road path portion 418, the expected electrical energy capacity of the power system 102 for the fifth road path portion 416 is determined, and so on. Accordingly, the power system 102 may be controlled from the current location 403 and for each road path portion 406 to arrive at the upcoming location at a desired state of charge level that is below a predetermined threshold level.

[0071] Now the last reference Figure 5 and Figure 6102 and a method of controlling the power system are described in more detail. During operation, the processing circuit of the control unit 114 determines S2 an upcoming location 204, 304, 404. The upcoming location 204, 304, 404 may be received from a location positioning module 502. The location positioning module 502 may determine the upcoming location based on any of the above examples (such as based on previous vehicle usage, map data, etc.).

[0072] The processing circuit determines S2 a current state of charge level of the energy storage system 104. Preferably, a signal is transmitted from the energy storage system 104 to the processing circuit so that the processing circuit can determine this information. Furthermore, a power distribution scheme between the electrical system 102 and the traction electric motor 101 is determined S3 to reach an upcoming location at a state of charge level of the energy storage system below a predetermined threshold level. Based on the power distribution scheme, the electrical system 102 is controlled S4 to feed power to the traction electric motor 101, e.g. during propulsion and to receive power from the traction electric motor 101 during braking. Furthermore, the electrical system 102 may be controlled to feed power to the traction electric motor 101, e.g. based on the power distribution scheme, from the fuel cell 106 only, from the energy storage system 104 only, or from a combination of the fuel cell 106 and the energy storage system 104.

[0073] Finally, when reaching the upcoming location 204 , 304 , 404 with a state of charge level below a predetermined threshold level and when the power system 102 assumes a low load operation mode, controlling S5 the power system 102 to feed power to at least the energy consumer 110 , 110 ′, 110 ″.

[0074] It should be understood that the present disclosure is not limited to the examples described above and shown in the accompanying drawings; rather, a person skilled in the art will recognize that many changes and modifications may be made within the scope of the appended claims. For example, a low-load operating mode may occur when the operator of the vehicle is at rest, and the energy consumer in this case is a control unit operating in the vehicle to track the vehicle alarm system, etc.

Claims

1. A computer-implemented method of controlling a power system of a fuel cell electric vehicle (FCEV), the power system comprising: a fuel cell and an energy storage system electrically connected to each other, wherein the FCEV comprises a traction electric motor connected to the electric power system, the electric power system being configured to feed electric power to the traction electric motor at a propulsion power level range during propulsion and to receive electric power generated by the traction electric motor during braking, the electric power system being operable to assume a low load operating mode in which electric power is fed to energy consumers of the FCEV at a power level below the propulsion power level range; and a processing circuit operatively coupled to the energy storage system, the method comprising: - determining, by the processing circuit, an upcoming position at which the power system will assume the low load mode of operation; - determining, by the processing circuit, a current state of charge level of the energy storage system; - determining, by the processing circuit, a power distribution scheme between the electrical system and the traction electric motor to reach the upcoming location at a state of charge level of the energy storage system below a predetermined threshold level; - controlling, by the processing circuit, the power system based on the power allocation scheme; and - When the power system assumes the low-load operation mode at the upcoming location, the power system is controlled by the processing circuit to feed power at least to the energy consumer.

2. The computer-implemented method of claim 1 , further comprising: - determining, by the processing circuit, a desired state of charge level of the energy storage system at the time of terminating the low load operating mode; - determining, by the processing circuit, an energy consumption level of the energy consumer during the low load operating mode; as well as - determining, by the processing circuit, a charge level of the fuel cell to the energy storage system during the low load operating mode; Wherein the predetermined threshold level of the energy storage system when the upcoming location is reached is based on the desired state of charge level and a difference between the charge level of the energy storage system and the energy consumption level of the energy consumer. 3 . The computer-implemented method of claim 2 , wherein the desired state of charge level of the energy storage system is based on topological data of a road path operable by the FCEV after the low load operating mode ends.

4. A computer implemented method according to any one of the preceding claims, wherein when the low load operation mode is assumed, the power system is controlled to feed power from the fuel cell to the energy consumer.

5. The computer-implemented method of any preceding claim, further comprising: - determining, by the processing circuit, the electric energy consumption of the traction electric motor to reach the upcoming position; The power allocation scheme is based on the determined power consumption. 6 . The computer-implemented method of claim 5 , wherein the determined electrical energy consumption is based on planned operating information of the traction electric motor for propelling the FCEV from a current location to the upcoming location.

7. The computer-implemented method of any one of claims 5 or 6, further comprising: - determining, by the processing circuit, a road topology of a road path from a current location to the upcoming location to be operated by the FCEV; and Wherein the determined power consumption is based on the road topology from the current location to the upcoming location.

8. The computer-implemented method of any one of claims 5 to 7, further comprising: - dividing, by the processing circuit, an upcoming road path from a current location to the upcoming location into a plurality of road path portions, each road path portion being associated with separate road topology data; Therein the electrical energy consumption of the traction electric motor is determined for each road path portion.

9. The computer-implemented method of claim 8, further comprising: - setting, by the processing circuit, a desired state of charge level of the energy storage system at the upcoming location, the desired state of charge level being below the predetermined threshold level; - determining, by the processing circuitry, a desired electrical energy capacity of the electrical power system for each road path portion to arrive at the upcoming location at the desired state of charge level of the energy storage system, the desired electrical energy capacity of each road path portion being based on its next upcoming road path portion; as well as - controlling, by the processing circuit, the power system based on the desired electrical energy capacity for each road path portion.

10. The computer-implemented method of any preceding claim, further comprising: - when the current state of charge level of the energy storage system is above an upper threshold level, controlling, by the processing circuit, the electric power system to feed electric power only from the energy storage system to the traction electric motor during at least a portion of a travel distance from a current location to the upcoming location.

11. A computer-implemented method according to any one of the preceding claims, wherein the fuel cell is operable to adopt an idle mode and a power mode, wherein in the idle mode, the fuel cell generates electricity at a first power level, and in the power mode, the fuel cell generates electricity at a second power level, the second power level being higher than the first power level.

12. The computer-implemented method of claim 11, wherein the fuel cell assumes the idle mode when the power system assumes the low-load operating mode.

13. A computer implemented method according to any one of claims 11 or 12, wherein the fuel cell assumes the idle mode when the power system is controlled to feed power from the energy storage system to the traction electric motor to reach the upcoming location.

14. The computer implemented method of any one of the preceding claims, wherein when the power system assumes the low load operating mode, the FCEV is arranged in a stationary operating mode.

15. The computer implemented method of any one of the preceding claims, wherein the energy consumer is a vehicle auxiliary system electrically connected to the power system.

16. A computer-implemented method according to any one of the preceding claims, wherein when the power system adopts the low-load operating mode, the energy consumer consumes power at a power level lower than the power level generated by the fuel cell, and wherein when the power system adopts the low-load operating mode, the difference between the power generated by the fuel cell and the power consumed by the energy consumer is fed from the fuel cell to the energy storage system.

17. The computer-implemented method of any preceding claim, further comprising: - determining, by the processing circuitry based on previous vehicle usage, the upcoming location at which the power system will assume the low load mode of operation.

18. The computer-implemented method of any one of claims 1 to 17, further comprising: - determining, by the processing circuitry based on map data, the upcoming location at which the power system will assume the low load mode of operation.

19. A power system for a fuel cell electric vehicle (FCEV), the power system comprising: Fuel cells; an energy storage system electrically connected to the fuel cell; and a control unit connected to the fuel cell, the power system being configured to feed power to the traction electric motor of the FCEV during propulsion in a propulsion power level range and to assume a low load operation mode, wherein the power system feeds power to the electrical consumers of the FCEV at a power level lower than the propulsion power level range, the control unit being configured to: - determining an upcoming location where the power system will adopt said low load operation mode; - determining a current state of charge level of the energy storage system; - determining a power distribution scheme between the electrical system and the traction electric motor to reach an upcoming location at a state of charge level of the energy storage system below a predetermined threshold level; - controlling the power system based on the power allocation scheme; as well as - When the power system assumes the low-load operation mode at the upcoming location, controlling the power system to feed power at least to the energy consumer.

20. A fuel cell electric vehicle (FCEV) comprising the power system according to claim 19.

21. A computer program comprising program code means for performing the method according to any one of claims 1 to 18 when said program is run on a computer.

22. A non-transitory computer readable medium carrying a computer program, the computer program comprising program code for executing the method of any one of claims 1 to 18 when the program product is run on a computer.

23. A control unit for controlling an auxiliary system of a transport vehicle, the control unit being configured to perform the method according to any one of claims 1 to 18.

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