Method for Controlling Power Supply System of Fuel Cell Electric Vehicle

Abstract

The present disclosure relates to a computer-implemented method for controlling a power supply system of a fuel cell electric vehicle (FCEV), the power supply system including a fuel cell and an energy storage system electrically connected to each other. A planned position at which the power supply system is to enter a low load operation mode is determined, and the power supply system is controlled based on a power distribution scheme to reach the planned position in a state where a state of charge level of the energy storage system is below a predetermined threshold level. Thereafter, when the power supply system enters the low load operation mode at the planned position, the power supply system is controlled to supply power to at least an energy consuming part.

Description

Technical Field

[0001] The present invention relates to an energy storage system and a power supply system including a fuel cell. In particular, the present invention relates to a method for controlling such a power supply system. The present invention is applicable to so-called fuel cell electric vehicles (FCEVs), particularly medium and large FCEVs. The present invention is described with respect to large FCEVs in the form of trucks, but the present disclosure is not limited to this particular vehicle and may be used in other FCEVs.

Background Art

[0002] The electric propulsion of passenger cars is becoming a conventional solution for reducing the environmental impact caused by vehicles. Development of large vehicles such as trucks is also continuing so that they can provide electric propulsion. The electric propulsion system includes one or more electric machines operable to generate propulsion torque on one or more wheels of the vehicle.

[0003] However, in large vehicles, it is necessary to increase the energy capacity of the battery that supplies power to the electric machine in order to provide a desired vehicle operating range. Therefore, the electrical capacity of the battery is a limiting factor for large vehicles.

[0004] Generating electricity using a fuel cell during vehicle operation is one approach to increasing the operating range of large vehicles. The electricity generated by the fuel cell can be supplied to one battery / multiple batteries or directly to the electromechanics that propel the vehicle. To reduce fuel cell degradation, it is preferable not to turn off the fuel cell during FCEV operation. However, during certain operating conditions, for example, because the state of charge of the energy storage system exceeds a certain limit, the energy storage system may not be able to receive the electricity generated by the fuel cell. In such cases, it is necessary to dissipate the electricity generated by the fuel cell or turn off the fuel cell. Dissipating electrical energy is not efficient, and as mentioned above, there is a desire not to shut down the fuel cell. Therefore, a solution that can avoid both is desired. Summary of the Invention

[0005] Accordingly, an object of the present disclosure is to mitigate the above deficiencies.

[0006] According to a first aspect, a computer-implemented method for controlling a power system of a fuel cell electric vehicle (FCEV) is provided, the power system including a fuel cell and an energy storage system electrically connected to each other, the FCEV including a traction motor connected to the power system, the power system being configured to supply power to the traction motor within a traction power level range during propulsion and to receive power generated by the traction motor during braking, the power system being operable to take a low-load operation mode in which power is supplied to an energy consumption part of the FCEV at a power level below the traction power level range, the method including a traction motor and a processing circuit operably coupled to the energy storage system, the method including determining, by the processing circuit, a planned position at which the power system is to take the low-load operation mode; determining, by the processing circuit, a current state of a charge level of the energy storage system; determining, by the processing circuit, a power distribution scheme between the power system and the traction motor for reaching the planned position in a state where the charge level of the energy storage system falls below a predetermined threshold level; controlling, by the processing circuit, the power system based on the power distribution scheme; and controlling, by the processing circuit, the power system to supply power to at least the energy consumption part when the power system takes the low-load operation mode at the planned position.

[0007] The energy consumption part is to be construed as a component or structure of the FCEV that consumes power from the power system. The energy consumption part may be, for example, vehicle headlights, an in-vehicle infotainment system, or further a control unit(s) of the FCEV operable with power. According to a preferred exemplary embodiment, the energy consumption part may be a vehicle auxiliary system electrically connected to the power system. The vehicle auxiliary part may be, for example, a crane operable by a driver of the vehicle to load and unload materials to / from the FCEV.

[0008] The position where the power system is expected to enter the low-load operation mode can be determined based on, for example, map data, statistical data from the previous usage status of one's own vehicle or other vehicles, i.e., historical data. Therefore, the expected position can be a predetermined position. As a result, according to an exemplary embodiment, the method may further include determining, by a processing circuit, based on map data, the position where the power system is expected to enter the low-load operation mode. The historical data can be received, for example, from artificial intelligence. Also, the historical data can be received from a memory stored in a back office or in the cloud, or from a memory forming part of a control unit arranged in the vehicle. Therefore, according to an exemplary embodiment, the method may further include determining, by a processing circuit, based on the previous usage status of the vehicle, the position where the power system is expected to enter the low-load operation mode.

[0009] Therefore, the expected position is the position where the power system enters the low-load operation mode and supplies power to the energy-consuming part. According to a non-limiting example, the expected position can be a traffic jam in front of the vehicle. In such a case, the power system supplies power to, for example, the power electronics that controls the operation of the vehicle's headlights, or the power electronics that controls the operation of other power-consuming parts that are active when the vehicle is stopped in a traffic jam queue. According to another non-limiting example, the expected position may be a loading / unloading position where the vehicle is stopped and is loaded / unloaded by the energy-consuming part in the form of the above-described vehicle auxiliary part.

[0010] Also, as described above, the low-load operation mode is a mode in which power is supplied at a level below the propulsion level range. Therefore, when the power system enters the low-load operation mode, it preferably cannot supply sufficient power to the traction motor for the propulsion of the FCEV. The power supplied to the energy-consuming part during the low-load operation mode can be within a range, that is, it does not need to be at a fixed power level.

[0011] Furthermore, the processing circuit preferably determines the topology of the planned road route to reach the planned position. Thus, the energy consumption for operating the FCEV along the planned road route can be determined. Thereby, an alternative is provided to reach the planned position in a state where the charge level is below a predetermined threshold level. Therefore, according to an exemplary embodiment, the power distribution scheme is based on the topology of the planned road route. In this context, the road topology is to be interpreted as the deformed form of the uphill and downhill of the planned road route. Therefore, the planned road route can include not only one or more uphill slopes of various angles and lengths but also one or more downhill slopes of various angles and lengths. The power distribution scheme is to be interpreted as the determined energy consumption of the power supply system along the road route until the planned position is reached. Therefore, the power distribution scheme preferably includes supplying power to the traction motor from the power supply system at different rates during propulsion and charging the energy storage system at different rates by supplying the power generated by the traction motor during braking to the energy storage system. Therefore, according to an exemplary embodiment, the method may further include determining, by the processing circuit, the electrical energy consumption of the traction motor to reach the planned position, and the power distribution scheme is based on the determined electrical energy consumption. The power distribution scheme preferably also includes the level of power generated by the fuel cell until the planned position is reached.

[0012] The present invention is based on the insight that by determining a planned position where the power supply system is to take a low-load operation mode, the power supply system can be controlled so that, before reaching this position, the state of the charge level of the energy storage system is below a predetermined threshold level when finally reaching the planned position. The advantage is that when reaching this position, the fuel cell can be operated to generate power, and the state of the charge level is at a low level so that any surplus power not consumed by the energy consuming part can be supplied to the energy storage system. Therefore, there is no need to turn off the fuel cell or dissipate the power. Therefore, the degradation rate of the fuel cell is reduced, and electrical energy is not wasted.

[0013] According to an exemplary embodiment, the method may further include determining, by a processing circuit, a desired state of a charge level of an energy storage system when ending a low load operation mode; determining, by the processing circuit, an energy consumption level of an energy consuming unit during the low load operation mode; and determining, by the processing circuit, a charge level of the energy storage system by a fuel cell during the low load operation mode, wherein a predetermined threshold level of the energy storage system when reaching a planned position is based on the desired state of the charge level and a difference between the charge level of the energy storage system and the energy consumption level of the energy consuming unit.

[0014] Accordingly, the predetermined threshold level of the energy storage system is based on, for example, subsequent usage of the FCEV when the low load operation mode ends. Thereby, it can be ensured that the FCEV can also manage future missions, that is, the power system can operate the drive motor in a desired manner. Preferably, according to an exemplary embodiment, the desired state of the charge level of the energy storage system may be based on topological data of a road route operable by the FCEV after the low load operation mode ends.

[0015] In this context, the road topology is desired to be interpreted as a deformed form of uphill and downhill of a planned road route. Accordingly, the planned road route may include not only one or more uphill slopes of various angles and lengths, but also one or more downhill slopes of various angles and lengths.

[0016] According to an exemplary embodiment, when taking the low load operation mode, the power system may be controlled to supply power from the fuel cell to the energy consuming unit. Thereby, the energy consuming unit mainly consumes electrical energy from the fuel cell. As described above, the surplus electrical energy is preferably supplied to the energy storage system.

[0017] According to an exemplary embodiment, the determined electrical energy consumption can be based on the scheduled operation information of the traction motor for propelling the FCEV from the current position to the planned position. Thereby, not only the power level consumed by the traction motor during propulsion but also the power level generated by the traction motor during braking can be determined. As an alternative or supplement, according to an exemplary embodiment, the method may further include determining, by a processing circuit, the road topology of a road route from the current position to the planned position where the FCEV operates, and the determined electrical energy consumption is based on the road topology from the current position to the planned position.

[0018] According to an exemplary embodiment, the method may further include dividing, by a processing circuit, the planned road route from the current position to the planned position into a plurality of road route sections, each road route section being associated with individual road topology data, and the electrical energy consumption of the traction motor being determined for each road route section.

[0019] By dividing a road route into a plurality of road route sections, the computational amount for estimating the electric energy consumption along the entire road trip is reduced as compared with the estimation of the electric energy consumption along the entire road route up to a planned position. Preferably, according to an exemplary embodiment, the method comprises setting, by a processing circuit, a desired state of a charge level of an energy storage system at a planned position, wherein the desired state of the charge level is less than a predetermined threshold level; determining, by the processing circuit, a desired electric energy capacity of a power supply system for each road route section to reach an end position in the desired state of the charge level of the energy storage system, wherein the desired electric energy capacity for each road route section is based on its next planned road route section; and further controlling, by the processing circuit, the power supply system based on the desired electric energy capacity for each road route section. Accordingly, a reverse calculation is performed based on the desired state of the charge level at the end position of the planned road route. Therefore, the FCEV needs to be able to operate without consuming the energy storage system and reach the end position in the desired state of the charge level. If the processing circuit determines that this is impossible by controlling the fuel cell to take a cruise mode, the fuel cell needs to be controlled to take a power mode throughout the planned road route until the end position is reached, i.e., for each road route section. Accordingly, the end position corresponds to the planned position.

[0020] According to an exemplary embodiment, the method may further include controlling, by a processing circuit, a power supply system to supply power to a traction motor only from an energy storage system during at least a portion of a travel distance from a current position to a planned position when a current state of a charge level of the energy storage system exceeds an upper threshold level. Thus, it should be understood that the fuel cell is still operating, i.e., not turned off, and supplying power to the energy storage system. Since the traction motor consumes more electrical energy than the electrical energy generated by the fuel cell, it can be ensured that at least a part of the electrical energy is consumed from the energy storage system when reaching the planned position. Also, when the state of the charge level exceeds the upper threshold level, it is necessary to supply power to the traction motor only from the energy storage system in order to reach the planned position in a state where the state of the charge level is below a predetermined threshold level. Thus, in this example, the predetermined threshold level is a lower predetermined threshold level.

[0021] According to an exemplary embodiment, the fuel cell may be operable to take an idle mode in which the fuel cell generates power at a first power level and a power mode in which the fuel cell generates power at a second power level, and the second power level is higher than the first power level.

[0022] The idle mode should be interpreted as the "sweet spot" of the fuel cell, i.e., the fuel cell operates to generate a power level at which the fuel degradation rate is kept to a minimum. When taking the idle mode, the fuel cell generates power at an intermediate position within its power range, i.e., at intermediate power. Thus, it is preferable that the fuel cell operates to take the idle mode as much as possible. Preferably, according to an exemplary embodiment, the fuel cell may take the idle mode when the power supply system takes a low-load operation mode. Thus, the fuel cell operates in its optimal operation mode even when taking the low-load operation mode.

[0023] According to an exemplary embodiment, when the power supply system is controlled to supply power from the energy storage system to the traction motor to reach a planned position, the fuel cell can enter an idle mode. The advantage is that the fuel cell operates optimally and additional power consumed by the traction motor to reach the planned position is received from the energy storage system.

[0024] According to an exemplary embodiment, when the power supply system enters a low load operation mode, the FCEV can be placed in a stopped state operation mode.

[0025] The stopped state operation mode is preferably interpreted as a mode in which the FCEV is in a stopped state with the parking brake engaged. Therefore, during the stopped state operation mode, the traction motor does not propel the vehicle.

[0026] According to an exemplary embodiment, the power consumption unit may be a vehicle auxiliary system electrically connected to the power supply system.

[0027] The vehicle auxiliary unit may be, for example, a crane positioned at the rear of the passenger compartment. Another vehicle auxiliary unit may be a winch or the like.

[0028] According to an exemplary embodiment, when the power supply system enters a low load operation mode, the energy consumption unit can consume power at a power level lower than the power level generated by the fuel cell. When the power supply system enters a low load operation mode, the difference between the power generated by the fuel cell and the power consumed by the energy consumption unit is supplied from the fuel cell to the energy storage system. Since the energy storage system is controlled to have a charge level below a predetermined threshold level when reaching the planned position, the energy storage system can 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, a power supply system for a fuel cell electric vehicle (FCEV) is provided. The power supply system includes a fuel cell, an energy storage system electrically connected to the fuel cell, and a control unit connected to the fuel cell. The power supply system is configured to supply power to the drive motor of the FCEV within a propulsion power level range during propulsion, and is also configured to take a low load operation mode in which the power supply system supplies power to the power consuming parts of the FCEV at a power level below the propulsion power level range. The control unit determines a planned position at which the power supply system is to take the low load operation mode, determines the current state of the charge level of the energy storage system, determines a power distribution scheme between the power supply system and the drive motor for reaching the planned position in a state where the charge level of the energy storage system is below a predetermined threshold level, controls the power supply system based on the power distribution scheme, and is configured to control the power supply system to supply power to at least the power consuming parts when the power supply system takes the low load operation mode at the planned position.

[0030] The control unit may include a microprocessor, a microcontroller, a programmable digital signal processor, or another programmable device. The control unit may further 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. When the control unit includes a programmable device such as the above-mentioned microprocessor, microcontroller, or programmable digital signal processor, the processor may further include computer-executable code for controlling the operation of the programmable device.

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

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

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

[0034] According to a fourth aspect, a computer program is provided, including program code means for performing any of the methods of the embodiments described above with respect to the first aspect when the program is executed on a computer.

[0035] According to a fifth aspect, a non-transitory computer-readable medium storing a computer program is provided, the computer program including program code for performing any of the methods of the embodiments described above with respect to the first aspect when the program is executed on a computer.

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

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

[0038] Further features of the present disclosure and advantages associated with the present disclosure will become apparent upon consideration of the appended claims and the following description. It will be recognized by those skilled in the art that different features of the present disclosure can be combined to create examples other than those described below without departing from the scope of the present disclosure.

[0039] The foregoing, as well as additional objects, features, and advantages of the present disclosure, will be better understood through the following non-limiting, detailed description of exemplary examples of the present disclosure.

Brief Description of the Drawings

[0040]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0041] The present disclosure will be described in more detail below with reference to the accompanying drawings showing exemplary examples. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the examples described herein. Rather, these examples are provided for completeness and thoroughness. Throughout the description, like reference characters refer to like elements.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The terms "comprises", "comprising", "includes" and / or "including", when used herein, specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0043] Terms such as "first", "second", etc. may be used in this specification to describe various elements, but it is also understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of the present disclosure, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element.

[0044] Relative terms such as "lower", "upper", "top", "bottom", "horizontal", "vertical", etc. may be used in this specification to describe the relationship of one element to another as shown in the figures. It will be understood that these terms, as well as the terms described above, are intended to encompass different orientations of the device in addition to the orientation shown in the figures. When an element is referred to as being "connected" or "coupled" to another element, it will be understood that the element may be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, no intervening elements are present.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that the terms used in this specification should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the related art, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0046] Referring specifically to FIG. 1, a fuel cell electric vehicle (FCEV) 10 is shown in the form of a truck. FCEV 10 is hereinafter simply referred to as a vehicle and includes a driving motor 101 for propelling the vehicle's wheels. In an exemplary embodiment, the driving motor 101 is arranged in the form of an electric machine. The driving motor 101 is arranged to receive power from the power system 102 during propulsion and supply the power generated by the electric machine 101 to the energy storage system 104 of the power system during braking. The energy storage system 104 is preferably a high-voltage battery of the vehicle 10. As will be apparent from the present disclosure, particularly with respect to FIG. 5 below, 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 power when receiving hydrogen fuel and oxygen.

[0047] The vehicle 10 also includes a control unit 114, which is connected to the power system 102 and controls 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 further 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. When the control unit 114 includes a programmable device such as the above-described microprocessor, microcontroller, or programmable digital signal processor, the processor may further include computer-executable code for controlling the operation of the programmable device.

[0048] Furthermore, vehicle 10 includes a plurality of energy consuming units 110, 110', 110''. The energy consuming units 110, 110', 110'' are to be interpreted as components or structures of vehicle 10 that receive electrical energy from the power supply system for their operation. In FIG. 1, the power consuming units 110, 110', 110'' are exemplified by the vehicle headlight system 110, the infotainment system 110' arranged in the passenger compartment 108 of vehicle 10, and the vehicle auxiliary unit 110'' in the form of a crane. In the latter example, the vehicle auxiliary unit 110'' preferably includes an electric motor 120 for operating the crane. Each of these energy consuming units is not only electrically connected to the power supply system 102 but also controllable by the control unit 114. Clearly, vehicle 10 includes a wide variety of additional energy consuming units, but they will not be described for the sake of clarity for the reader.

[0049] During the propulsion of vehicle 10, power is generated by the fuel cell 106, and the power is supplied to the energy storage system 104, whereby the electrical energy is charged into the energy storage system 104. Also, the energy generated by the fuel cell 106 may be directly supplied to the traction motor 101 during propulsion. Also, the power is preferably supplied from the energy storage system 104 to the traction motor 101 during propulsion. Therefore, when propelling vehicle 10, the energy storage system 10 is steadily consumed from the electrical energy consumed by the traction motor 101.

[0050] To reduce the degradation of the fuel cell 106, the fuel cell 106 preferably not only does not operate in the power mode but also is not turned off. Instead, the fuel cell 106 preferably operates in the idle mode to reduce its degradation. In the power mode, the fuel cell 106 generates power at a relatively high level, and in the idle mode, the fuel cell 106 generates power at a relatively medium level. When the vehicle 10 is operated and reaches a position where the vehicle is in a stopped state, that is, a position where the traction motor is turned off and does not consume power from the power system 102, the fuel cell 106 preferably does not turn off. In these situations, the power system 102 is operable to take a low-load operation mode, and in this low-load operation mode, power is supplied from the power system 102 to at least one of the aforementioned energy-consuming components. When the power system 102 takes the low-load operation mode, the power system supplies power to the energy-consuming component at a power level lower than the range of the traction power level supplied to the traction motor 101 during propulsion.

[0051] However, when the vehicle 10 is in a stopped state and power is being supplied to the energy-consuming component(s) 110, 110', 110'', if the state of charge level of the energy storage system 104 exceeds a predetermined threshold level, any surplus electrical energy not consumed by the energy-consuming component(s) 110, 110', 110'' may not be absorbed by the energy storage system 104 because the energy storage system 104 may be "full". Therefore, it may be necessary to turn off the fuel cell 106 or dissipate the surplus power generated by the fuel cell 106. In the following, various operation scenarios for reaching a position where the power system is scheduled to take the low-load operation mode without the need to turn off the fuel cell 106 or dissipate useful electrical energy will be described. Therefore, reference is made here to FIGS. 2 and 3.

[0052] First, referring to FIG. 2, FIG. 2 shows a vehicle 10 operating on a road route 202 for the crane to reach a planned position 204 where the material 206 is to be loaded onto the vehicle 10. The planned position 204 is also referred to as the loading position 204 hereinafter with reference to FIG. 2. When the vehicle 10 reaches this planned position 204, the driving motor 101 is turned off, and the vehicle auxiliary unit 110'', i.e., the crane, consumes electrical energy from the power supply system 102 during loading. Specifically, the motor 120 of the crane consumes electrical energy when the vehicle 10 takes the stopped state operation mode at the planned position 204. The distance 210 from the current position to the planned position 204 is only schematically illustrated, and it will be easily understood that the following description is of course also valid for distances significantly longer than the distance shown in FIG. 2.

[0053] During operation and before the vehicle 10 reaches the planned position 204, the processing circuit of the control unit 114 determines that the vehicle 10 is moving the crane towards the position 204 where the material 206 is to be loaded onto the vehicle, i.e., at this position 204, the power supply system 102 takes the low load operation mode.

[0054] 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 the charge level of the energy storage system 104. Based on the current state of the charge level, the processing circuit determines a power distribution scheme between the power supply system 102 and the traction motor for loading in a state where the charge level state is below a predetermined threshold level. Therefore, an appropriate power distribution scheme can be determined based on the predicted energy consumption of the traction motor 101 when operating the vehicle 10 over the distance 210 to the loading position. Therefore, the power distribution scheme needs to ensure that the vehicle 10 fulfills the mission of reaching the loading position 204, but when reaching the loading position, the charge level state needs to be below a predetermined threshold level. The power distribution scheme may consider a road topology where the energy storage system 104 may be charged at any time when the traction motor is operated to generate power during braking. Also, the fuel cell 106 may operate to take the power mode at any time when necessary to reach the loading position when traveling the distance 210 to the loading position 204, but the fuel cell 106 preferably operates to take the idle mode as much as possible. However, during at least a part of the distance traveled from the current position to the planned position, the power supply system 102 is controlled to supply power to the traction motor 101 only from the energy storage system, especially when the current state of the charge level of the energy storage system 104 exceeds the upper threshold level.

[0055] The loading position 204 can be determined by the processing circuit based on the previous usage status of the vehicle. In particular, the processing circuit may know from previous operations that the vehicle 10 will soon reach the loading position 204. Also, the processing circuit may receive the position 204 from map data, such as GPS for example.

[0056] Thereby, the power supply system 102 is controlled to operate according to the power distribution scheme from the current position to the loading position 204, so that the charge level state of the energy storage system 104 is below a predetermined threshold level.

[0057] The predetermined threshold level of the energy storage system 104 when reaching the scheduled position 204 can be based on the desired state of the charge level of the energy storage system 104 after the low-load operation mode has ended. In particular, when operating the vehicle 10 on the road route 240 after loading the material 206, it may be desirable to have a sufficient state of charge level of the energy storage system 104. Therefore, the desired state of the charge level of the energy storage system 104 is preferably based on the topological data of the road route 240 operable by the vehicle 10 after the low-load operation mode has ended, i.e., after the crane 110'' has loaded the material 206 onto the vehicle 10 and the vehicle is ready for its next assignment. Therefore, the topological data can function as an indicator of the power distribution scheme between the power supply system 102 and the traction motor 101 when operating the subsequent road route 240. In other words, the processing circuit can determine the power level supplied from the energy storage system 104 to the traction motor 101 during propulsion on a road route operable after loading the material 206, or the power level supplied from the traction motor 101 to the energy storage system 104 during braking on a road route operable after loading the material 206.

[0058] The processing circuit may also determine the energy consumption level of the energy-consuming unit during the low-load operation mode. Therefore, when loading the material 206, the processing circuit determines the amount of energy required to operate the crane. Furthermore, the processing circuit can determine the charge level of the energy storage system 104 by the fuel cell 106 during the low-load operation mode. The predetermined threshold level of the energy storage system 104 when reaching the scheduled position, i.e., the loading position 204 of the material, can thus be based on the desired state of the charge level when the low-load operation mode has ended and the difference between the charge level of the energy storage system and the energy consumption level of the energy-consuming unit. Therefore, the predetermined threshold level is based on the energy level required to operate the vehicle subsequently when the material 206 is loaded onto the vehicle and the charge level of the energy storage system 104 during loading of the material 206.

[0059] When the vehicle 10 reaches the loading position 204, the power supply system 102 is controlled to supply power to the crane's electric motor 120. Preferably, when the vehicle reaches the loading position and the power supply system takes the low-load operation mode, the fuel cell 106 is controlled to take the idle mode. Also, the power supply system 102 is preferably controlled to supply power from the fuel cell 106 to the crane's electric motor 120.

[0060] The crane's electric motor 120 can consume power at a power level lower than the power level generated by the fuel cell when the power supply system takes the low-load operation mode. In other words, when the fuel cell 106 takes the idle mode, it generates more power than the power consumed by the crane's electric motor 120. Since the state of charge level of the energy storage system 104 is below a predetermined threshold level, the difference between the power generated by the fuel cell and the power consumed by the energy-consuming part can be supplied from the fuel cell to the energy storage system. When loading the material 206 onto the vehicle 10, there is no need to dissipate electrical energy, nor is it necessary to turn off the fuel cell 106.

[0061] Referring now to FIG. 3, another situation is shown where the power supply system 102 is controlled in the same manner as described above with respect to FIG. 2. In the example of FIG. 3, the planned position 304 is a position where a queue has formed along the road, the vehicle 10 is placed in the stop state operation mode, and the power supply system 102 takes the low-load operation mode. When reaching the queue, the power supply system 102 supplies power to, for example, the vehicle's headlight 110, the infotainment system 110', etc. Therefore, these energy-consuming parts require power for their operations.

[0062] When the vehicle is at a position 310 away from forming a queue, the processing circuit may receive a signal indicating the planned stop state operation mode from, for example, a GPS system, an upper layer control system, etc. Thereby, the processing circuit can determine a power distribution scheme in the same manner as described above with respect to the example of FIG. 2, and control the power system accordingly. When reaching the queue formation, the power system 102 supplies power to the energy consumption unit, and the surplus power generated by the fuel cell 106 during the idle mode is supplied from the fuel cell 106 to the energy storage system 104.

[0063] Therefore, it will be easily understood that the power system 102 is controlled in the same manner as in the exemplary embodiment of FIG. 2 even in the exemplary embodiment of FIG. 3.

[0064] Referring now to FIG. 4, FIG. 4 is a schematic diagram of a planned road route 402 operable by a vehicle 10 according to an exemplary embodiment. The vehicle 10 is illustrated as being operable between a current position 403 and a planned position 404 where the power system 102 is operable to take a low-load operation mode. Before the vehicle 10 leaves the current position 403, the processing circuit divides the planned road route 402 into a plurality of road route sections 406. Therefore, the sum of all the road route sections 406 corresponds to the length of the planned road route 402. Each road route section is associated with individual road topology data. As can be seen from FIG. 4, the first road route section 408, the second road route section 410, and the fourth road route section 414 are uphill slopes, where the power system 102 supplies power to the traction motor 101 to operate in these sections, and the third road route section 412, the fifth road route section 416, and the sixth road route section 418 are mainly downhill slopes, where the energy storage system 104 receives power from the traction motor 101 during braking. Thereby, the processing circuit can determine the electrical energy consumption of the traction motor for each road route section 406.

[0065] The processing circuit can preferably set a desired state of the charge level of the energy storage system at the planned position 404. For the power supply system 102 to operate in a low-load operation mode at the planned position 404, the desired state of the charge level needs to be below a predetermined threshold level. Further, the processing circuit determines the desired electrical energy capacity of the power supply system for each road route section to reach the end position with the desired state of the charge level of the energy storage system. The desired electrical energy capacity for each road route section is based on the next planned road route section. In other words, after the desired state of the charge level at the planned position 404 is determined, the desired electrical energy capacity of the power supply system 102 for the sixth road route section 418 is determined. Thereby, the desired state of the charge level at the start 419 of the sixth road route section 418 can be determined. Then, based on the desired state of the charge level at the start 419 of the sixth road route section 418 and the like, the desired electrical energy capacity of the power supply system 102 for the fifth road route section 416 is determined. Thereby, the power supply system 102 can be controlled to reach the planned position with the desired state of the charge level below the predetermined threshold level from the current position 403 and for each road route section 406.

[0066] Finally, referring here to FIGS. 5 and 6, the power supply system 102 and its control method will be described in more detail. During operation, the processing circuit of the control unit 114 determines the planned positions 204, 304, 404 (S2). The planned positions 204, 304, 404 may be received from the position identification module 502. The position identification module 502 can determine the planned position according to any of the above examples, for example, based on the previous usage status of the vehicle, map data, and the like.

[0067] The processing circuit determines the current state of the charge level of the energy storage system 104 (S2). Preferably, a signal is transmitted from the energy storage system 104 to the processing circuit so that the processing circuit can determine this information. Further, a power distribution scheme between the power supply system 102 and the traction motor 101 is determined for reaching the planned position in a state where the charge level state of the energy storage system is below a predetermined threshold level (S3). Based on the power distribution scheme, the power supply system 102 is controlled to supply power to the traction motor 101 during propulsion and receive power from the traction motor 101 during braking, for example (S4). Also, the power supply system 102 may be controlled to supply power to the traction motor 101 from, for example, only the fuel cell 106, only the energy storage system 104, or a combination of the fuel cell 106 and the energy storage system 104, based on the power distribution scheme.

[0068] Finally, when the charge level state reaches the planned positions 204, 304, 404 in a state where it is below a predetermined threshold level, and when the power supply system 102 takes a low-load operation mode, the power supply system 102 is controlled to supply power to at least the energy consumption units 110, 110', 110'' (S5).

[0069] Naturally, it is understood that the present disclosure is not limited to the examples described above and illustrated in the drawings, but rather, as will be understood by those skilled in the art, many variations and modifications may be made within the scope of the appended claims. For example, the low-load operation mode may occur when the driver of the vehicle is resting, and the energy consumption unit is in a situation where it operates in the vehicle so that the control unit(s) can continue to monitor a vehicle warning system or the like.

Claims

1. A computer-implemented method for controlling a power system of a fuel cell electric vehicle (FCEV), wherein the power system includes a fuel cell and an energy storage system electrically connected to each other, and the FCEV is a traction motor connected to the power system, and the power system is configured to supply power to the traction motor within a propulsion power level range during propulsion and to receive power generated by the traction motor during braking, and the power system is operable to take a low-load operation mode in which power is supplied to an energy consuming part of the FCEV at a power level below the propulsion power level range, the method comprising: a traction motor; and a processing circuit operably coupled to the energy storage system, the method comprising: determining, by the processing circuit, a planned position at which the power system is to take the low-load operation mode; determining, by the processing circuit, a current state of a charge level of the energy storage system; determining, by the processing circuit, a power distribution scheme between the power system and the traction motor for reaching the planned position in a state where the charge level of the energy storage system is below a predetermined threshold level; controlling, by the processing circuit, the power system based on the power distribution scheme; controlling, by the processing circuit, the power system to supply power to at least the energy consuming part when the power system takes the low-load operation mode at the planned position; the method comprising the steps of.

2. the method comprising: determining, by the processing circuit, a desired state of a charge level of the energy storage system when ending the low-load operation mode; determining, by the processing circuit, an energy consumption level of the energy consuming part during the low-load operation mode; determining, by the processing circuit, a charge level of the energy storage system by the fuel cell during the low-load operation mode; further comprising: The computer-implemented method according to claim 1, wherein the predetermined threshold level of the energy storage system when reaching the planned position is based on a desired state of the charge level and a difference between the charge level of the energy storage system and the energy consumption level of the energy consuming part.

3. The desired state of the charging level of the energy storage system is based on topological data of a road route operable by the FCEV after the low load operation mode ends, the computer-implemented method according to claim 2.

4. The power supply system is controlled to supply power from the fuel cell to the energy consumption unit when taking the low load operation mode, the computer-implemented method according to any one of the preceding claims.

5. Further comprising determining, by the processing circuit, the amount of electrical energy consumption of the traction motor for reaching the planned position, The power distribution scheme is based on the determined amount of electrical energy consumption, the computer-implemented method according to any one of the preceding claims.

6. The determined amount of electrical energy consumption is based on the scheduled operation information of the traction motor for propelling the FCEV from the current position to the planned position, the computer-implemented method according to claim 5.

7. Further comprising determining, by the processing circuit, the road topology of the road route from the current position where the FCEV operates to the planned position, The determined amount of electrical energy consumption is based on the road topology from the current position to the planned position, the computer-implemented method according to any one of claims 5 or 6.

8. Further comprising dividing, by the processing circuit, the planned road route from the current position to the planned position into a plurality of road route sections, each road route section being associated with individual road topology data, The amount of electrical energy consumption of the traction motor is determined for each road route section, the computer-implemented method according to any one of claims 5 to 7.

9. Setting, by the processing circuit, a desired state of the charging level of the energy storage system at the planned position, wherein the desired state of the charging level is below the predetermined threshold level, the setting, Determining, by the processing circuit, a desired electrical energy capacity of the power supply system for each road route section for reaching the planned position in the desired state of the charging level of the energy storage system, wherein the desired electrical energy capacity for each road route section is based on the next planned road route section, the determining, controlling the power system by the processing circuit based on the desired electrical energy capacity for each of the road path sections; The computer-implemented method according to claim 8, further comprising.

10. When the current state of the charge level of the energy storage system exceeds an upper threshold level by the processing circuit, controlling the power system to supply power to the traction motor only from the energy storage system during at least a part of the driving distance from the current position to the planned position. The computer-implemented method according to any one of the preceding claims.

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

12. When the power system takes the low-load operation mode, the fuel cell takes the idle mode. The computer-implemented method according to claim 11.

13. When the power system is controlled to supply power from the energy storage system to the traction motor for reaching the planned position, the fuel cell takes the idle mode. The computer-implemented method according to any one of claims 11 or 12.

14. When the power system takes the low-load operation mode, the FCEV is arranged in a stopped state operation mode. The computer-implemented method according to any one of the preceding claims.

15. The energy consuming unit is a vehicle auxiliary system electrically connected to the power system. The computer-implemented method according to any one of the preceding claims.

16. When the power system takes the low-load operation mode, the energy consuming unit consumes power at a power level lower than the power level generated by the fuel cell, and when the power system takes the low-load operation mode, the difference between the power generated by the fuel cell and the power consumed by the energy consuming unit is supplied from the fuel cell to the energy storage system. The computer-implemented method according to any one of the preceding claims.

17. The computer-implemented method according to any one of the preceding claims, further comprising determining, by the processing circuit, a planned position at which the power supply system takes the low-load operation mode based on a previous vehicle usage situation.

18. The computer-implemented method according to any one of claims 1 to 17, further comprising determining, by the processing circuit, a planned position at which the power supply system takes the low-load operation mode based on map data.

19. A power supply system for a fuel cell electric vehicle (FCEV), the power supply system including a fuel cell, an energy storage system electrically connected to the fuel cell, and a control unit connected to the fuel cell, the power supply system being configured to supply power to a traction motor of the FCEV within a traction power level range during propulsion, and the power supply system being configured to take a low-load operation mode in which power is supplied to a power consumption unit of the FCEV at a power level below the traction power level range. The control unit is configured to determine a planned position at which the power supply system takes the low-load operation mode. configured to determine a current state of a charge level of the energy storage system. configured to determine a power distribution scheme between the power supply system and the traction motor for reaching the planned position in a state where the charge level of the energy storage system falls below a predetermined threshold level. configured to control the power supply system based on the power distribution scheme. The power supply system, configured to control the power supply system to supply power to at least the power consumption unit when the power supply system takes the low-load operation mode at the planned position.

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

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

22. A non-transitory computer-readable medium holding a computer program, the computer program including program code for performing the method according to any one of claims 1 to 18 when the program product is executed on a computer.

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

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