Power source assembly for aerial vehicle

Abstract

There is provided a power source assembly having: a fuel cell module configured to provide a first DC power output; a battery module configured to provide a second DC power output; a direct current bus configured to provide a net direct current power output to a load; a DC / DC converter electrically connected to the DC bus, the DC / DC converter configured to receive a first DC power output from the fuel cell module or a second DC power output from the battery module; and a controller operably coupled to the DC / DC converter and configured to receive data indicative of the first DC power output, the controller configured to control the DC / DC converter based on the data indicative of the first DC power output to maintain a slew rate from the fuel cell module within a slew rate range.

Description

Technical Field

[0001] The present disclosure relates to a power source assembly for an aerospace vehicle. Background Art

[0002] Aircraft vehicles use a variety of power sources to drive one or more propellers that can generate thrust for the vehicle. Many vehicles use gas turbine engines having a turbine and rotor assembly. While gas turbine engines have made significant advances over the years, it may be beneficial to investigate including other power sources as a primary or secondary power source for the vehicle. However, in the process of developing new power sources, it may be important to ensure that the new technology does not introduce other inefficiencies in the form of excess weight, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] A full and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0004] Figure 1 is a schematic perspective view of an aerial vehicle according to aspects of the present disclosure.

[0005] Figure 2 is a schematic perspective view of a gas turbine engine according to aspects of the present disclosure.

[0006] Figure 3 is a schematic perspective view of an electric thruster according to aspects of the present disclosure.

[0007] Figure 4 is a schematic diagram of a fuel cell module according to an exemplary aspect of the present disclosure.

[0008] Figure 5 is a schematic diagram of a power source assembly for an aerospace vehicle according to an exemplary aspect of the present disclosure.

[0009] Figure 6 is a schematic diagram of a power source assembly for an aerospace vehicle according to another exemplary aspect of the present disclosure.

[0010] Figure 7 is a graph depicting the division of net output power of power source components according to an exemplary aspect of the present disclosure.

[0011] Figure 8 is a schematic diagram of a power source assembly for an aerospace vehicle according to another exemplary aspect of the present disclosure.

[0012] Fig. 9 is a schematic diagram of a power source assembly for an aerospace vehicle according to yet another exemplary aspect of the present disclosure.

[0013] Fig.10is a schematic diagram of a power source assembly for an aerospace vehicle according to another exemplary aspect of the present disclosure.

[0014] Fig.11 is a schematic diagram of a controller according to an exemplary aspect of the present disclosure.

[0015] Fig.12 is a flow chart of a method for controlling a power source assembly of the present disclosure. DETAILED DESCRIPTION

[0016] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter references to refer to features in the drawings. Like or similar reference numbers in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0017] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. In addition, unless expressly stated otherwise, all embodiments described herein should be considered exemplary.

[0018] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0019] The term "at least one" in a context such as "at least one of A, B, and C" means only A, only B, only C, or any combination of A, B, and C.

[0020] The phrases "from X to Y" and "between X and Y" both refer to a range of values ​​including the endpoints (ie, to a range of values ​​including X and Y).

[0021] As used herein, the term "maximum power draw" refers to the maximum amount of electrical power required by a particular component during all expected non-fault mode and non-emergency mode operations of the particular component.

[0022] The present disclosure generally relates to a power source assembly for an aircraft vehicle. The power source assembly can be configured to drive a load, such as an electric propeller of an aircraft vehicle. The power source assembly can generally include: a fuel cell module configured to provide a first direct current (DC) power output; a battery module configured to provide a second DC power output; a DC / DC converter configured to receive a first DC power output from the fuel cell module or a second DC power output from the battery module; and a controller. The controller can be operably coupled to the DC / DC converter and configured to receive data indicating the first DC power output. The controller can also be configured to control the DC / DC converter based on the data indicating the first DC power output to maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module.

[0023] In this way, it should be understood that the DC / DC converter can ensure that the power output of the fuel cell module does not change too quickly in response to changes in the power output demand on the power source assembly. For example, it should be understood that rapid changes in the amount of power drawn from the fuel cell module during flight operations can have a negative impact on the life and reliability of the fuel cell module. For example, if a proton exchange membrane fuel cell (PEMFC) is subjected to rapid load changes, certain catalysts may dissolve, and / or low reactant conditions may occur. A battery module with a rated power comparable to the rated power of the fuel cell module can be provided to support the fuel cell module during sudden load demands. The power output assembly topology and control method disclosed herein allow the battery module to have a much smaller rated power without affecting the life of the fuel cell module.

[0024] For example, in response to a request to increase the net power output of the power source assembly, the controller can start a ramp-up of the first DC power output of the fuel cell module at a rate within the slew rate range of the fuel cell module. In order to ensure that the net power output of the power source assembly is sufficient to meet the power output demand on the power source assembly, the battery module can provide the difference between the current first DC power output and the power output demand essentially instantaneously. A second DC / DC converter can be provided to provide this functionality. As the first DC power output of the fuel cell module ramps up and reaches the power output demand, the second DC power output of the battery module is correspondingly reduced. This configuration can allow for a much smaller capacity battery module, allowing for an overall lighter system, while still providing a tightly regulated DC bus voltage for the load.

[0025] Referring now to the drawings, in which like numerals represent like elements throughout, Figure 1 is a schematic diagram of an air vehicle 100 according to an exemplary embodiment of the present disclosure. Figure 1The exemplary air vehicle 100 of is configured as an aircraft. The aircraft generally includes a fuselage 102 forming a main body of the vehicle 100, a first wing 104 extending from the port side of the aircraft, and a second wing 106 extending from the starboard side of the aircraft. The first and second wings 104, 106 each extend laterally from the fuselage 102. The aircraft also includes a tail 108 having one or more stabilizers 110, and in particular, vertical stabilizers and horizontal stabilizers.

[0026] The vehicle 100 also includes a propulsion system 112 that includes one or more thrusters 114 and one or more power sources 116. The propulsion system 112 also includes an electrical power distribution bus 118 that electrically couples the various components of the propulsion system 112.

[0027] Reference now Figure 2 , providing a way to combine Figure 1 1 is a schematic diagram of a propeller in an exemplary propulsion system 112 of a vehicle 100. More specifically, for the depicted embodiment, the propeller is configured as a gas turbine engine 120, and more specifically, Figure 2 The gas turbine engine 120 is configured as a turbofan engine. The turbofan engine includes a fan section 122 and a turbine 124 drivingly coupled to the fan section 122. The turbofan engine also includes an outer nacelle 126 that at least partially surrounds the fan section 122 and the turbine 124. The turbine 124 generally includes a compressor section 128, a combustion section 130, and a turbine section 132 arranged in a serial flow order, and one or more shafts 134 that connect, for example, the fan of the fan section 122, one or more compressors of the compressor section 128, and one or more turbines of the turbine section 132. In addition, for Figure 2 In an embodiment of the present invention, the turbofan engine further includes an electric motor 136 that can rotate with one or more shafts 134 of the turbine 124, the fan section 122, or both. The electric motor 136 can be configured to extract electrical power from the turbofan engine and provide such electrical power to the electrical power distribution bus 118, such as Figure 1 Additionally or alternatively, motor 136 may be configured to receive electrical power from electrical power distribution bus 118 to drive a fan of fan section 122, for example.

[0028] Reference now Figure 3 , provides another exemplary aspect of the present disclosure that can be combined with Figure 1 Schematic diagram of a propeller in an exemplary propulsion system 112 of a vehicle 100. Figure 3In the embodiment of the present invention, the propeller is configured as an electric fan 140. The electric fan 140 generally includes an inverter 142, a motor 144 and a fan 146.

[0029] The inverter 142 is configured to receive power from, for example, an electrical power distribution bus 118 (such as Figure 1 The electric power distribution bus 118 of the inverter 142 receives electric power and converts the received electric power from, for example, direct current ("DC") electric power to alternating current ("AC") electric power. The motor 136 is configured as an electric motor that receives electric power from the inverter 142 and converts the electric power into mechanical rotational force to drive the fan 146 and generate thrust.

[0030] Reference now Figure 4 According to exemplary aspects of the present disclosure, there is provided a method that can be combined with Figure 1 The power source in the exemplary propulsion system 112 of the vehicle 100 is shown in FIG. More specifically, the power source is a fuel cell 150. A fuel cell is an electrochemical device that can convert chemical energy from a fuel (such as hydrogen) into electrical energy through an electrochemical reaction of the fuel (such as hydrogen) with an oxidant (such as oxygen contained in the atmosphere).

[0031] Figure 4 The fuel cell 150 includes an anode 152, a cathode 154, and an electrolyte layer 156 positioned between the anode 152 and the cathode 154. During operation, a fuel (such as hydrogen fuel) is provided to the anode 152, and an oxygen-containing gas (such as air) is provided to the cathode 154. Within the anode 152, hydrogen molecules from the fuel can be separated into protons and electrons, wherein the electrolyte layer 156 only allows the protons to pass through to the cathode 154. The electrons travel through an external circuit 158, which can be electrically coupled to the electrical power distribution bus 118 through a junction box 160 (including, for example, various power electronics), such as Figure 1 The electrical power distribution bus 118. At the cathode 154, the protons, electrons and oxygen combine to form water as a byproduct.

[0032] As will be understood, Figure 1 The vehicle 100 depicted in FIG. 1 is provided as an example only, and in other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable aviation vehicle 100. Similarly, Figures 1 to 3The propellers depicted in are also provided as examples only. In other exemplary embodiments, aspects of the present disclosure may be incorporated into or otherwise used with any other suitable propeller, such as any other suitable gas turbine engine with an electric motor (e.g., other turbofan engines, open rotor turbofan engines, turboprop engines, turboshaft engines, turbojet engines), any other suitable electric fan (e.g., ducted fans, distributed fans, vertical thrust fans, horizontal thrust fans, combined fans), etc.

[0033] Furthermore, it should be understood that Figure 4 The fuel cell 150 depicted as a power source in FIG. 1 may be any suitable type of fuel cell. Figure 4 A single fuel cell is depicted in , but it should be understood that, as used herein, the term "fuel cell" may refer to a single fuel cell or a fuel cell array connected to each other to provide an electrical power output. In particular, since a single fuel cell may only generate about 1 volt, multiple fuel cells can be stacked together (which may be referred to as a fuel cell stack). One or more fuel cell stacks may form a fuel cell module, and one or more fuel cell modules may be used in a fuel cell system to generate a desired voltage. In addition, the fuel cell may have any suitable chemical substance. For example, the fuel cell 150 may include a solid oxide fuel cell (SOFC), a molten carbonate fuel cell (MCFC), a phosphoric acid fuel cell (PAFC), and a proton exchange membrane fuel cell (PEMFC), all of which are generally named after their respective electrolyte layers. Each of these fuel cells may have specific benefits in the form of a preferred operating temperature range, power generation capacity, efficiency, etc.

[0034] Reference now Figure 5 , a schematic diagram of a power source assembly 200 for an aerospace vehicle is provided according to an exemplary aspect of the present disclosure. Figure 5 The exemplary power source assembly 200 may be integrated into one or more of the exemplary aerospace vehicles described herein (see, e.g., Figure 1 100), which may be used with one or more of the thrusters described herein (see e.g. Figure 2 and Figure 3 ), and may utilize one or more of the exemplary power sources described herein (see e.g. Figure 4 ).

[0035] More specifically, Figure 5 Schematically depicted is the circuitry of power source assembly 200. As will be appreciated, power source assembly 200 includes fuel cell module 202, battery module 204, DC bus 206, battery DC / DC converter 208, fuel cell DC / DC converter 210, and controller 212.

[0036] In short, it should also be understood that for the depicted embodiment, the power source assembly 200 includes a controller 215 that is operably coupled to the battery DC / DC converter 208 and is configured to receive data indicating the regulated battery DC voltage output V2 (as shown by line 217). However, in other embodiments, the data received by the controller 215 may be a regulated power output, a regulated current output, or some combination thereof. The controller 215 is configured to control the battery module 204 based on the received data indicating the regulated battery DC voltage output V2.

[0037] The fuel cell module 202 may include one or more fuel cell stacks (which in turn may include a plurality of fuel cells, such as Figure 4 150) and is configured to provide a fuel cell module DC power output P during operating conditions such as the power source assembly 200. FC In particular, the fuel cell module 202 is configured to provide a fuel cell voltage output V during operating conditions of the power source assembly 200. FC and the fuel cell module current output I FC The fuel cell module 202 may be configured to generate a maximum power output of at least 100 kilowatts (kW) and up to 2000 kW, such as between 200 kW and 1200 kW.

[0038] The battery module 204 is configured to provide a battery DC power output P during operating conditions of the power source assembly 200, such as BAT Specifically, the battery module 204 is configured to provide a battery voltage output V during operating conditions of the power source assembly 200. BAT and battery current output I BAT Battery module 204 may be configured in any suitable manner to store electrical power. In certain exemplary embodiments, battery module 204 may include one or more lithium-ion batteries and / or one or more batteries of other suitable chemistries.

[0039] The battery module 204 may be configured to store at least 17 kilowatt-hours (kWh) and up to 30 kWh. In this manner, as will be appreciated from the description herein, the storage capacity of the battery module 204 may be relatively low compared to the maximum power output of the fuel cell module 202. For example, the ratio of the storage capacity of the battery module 204 to the maximum power output of the fuel cell module 202 may be less than 30 kWh to 850 kW (which is equivalent to less than 2 minutes and 7 seconds of maximum power output).

[0040] Battery DC / DC converter 208 is cascade electrically connected to battery module 204, and more specifically, directly cascade electrically connected to battery module 304. As used herein, the term "direct cascade electrically connected" refers to a cascade electrical connection between two components without power electronics in the electrical connection between them.

[0041] The battery DC / DC converter 208 is configured to regulate its output voltage V2 from the battery module 204 while allowing the battery current output I BAT The regulated battery DC power output can be positive, such as Figure 5 , or it may be negative (charging battery module 204).

[0042] The fuel cell DC / DC converter 210 is cascade-connected and electrically connected to the fuel cell module 202 to receive the DC power output P of the fuel cell module. FC More specifically, for the depicted embodiment, the fuel cell DC / DC converter 210 is directly cascaded electrically connected to the fuel cell module 202. The fuel cell DC / DC converter 210 is configured to regulate the fuel cell module voltage output V from the fuel cell module 202. FC (or fuel cell module current output I FC , or vice versa). As will be appreciated, the fuel cell DC / DC converter 210 is a unidirectional DC / DC converter, allowing current only from the fuel cell module 202.

[0043] The controller 212 is operably coupled to the fuel cell DC / DC converter 210 and is configured to receive a signal indicating the fuel cell module DC power output P FC For the embodiment shown, the DC power output P of the fuel cell module is indicated. FC The data is the fuel cell module current output I from the fuel cell module 202 FC However, as shown by the dashed line, in other embodiments, the DC power output P of the fuel cell module is indicated. FC The data may be the fuel cell module voltage output V from the fuel cell module 202 FC .

[0044] The controller 212 is configured to determine the DC power output P of the fuel cell module based on the received indication. FC202 to control the fuel cell DC / DC converter 210 based on the data from the fuel cell module 202 to maintain the slew rate from the fuel cell module 202 within the slew rate range of the fuel cell module 202, as discussed below. (It is worth noting that the controller 212 is therefore configured to operate in a different manner than the controller 215.) It should be understood that as used herein, the term "slew rate" related to the fuel cell module 202 refers to the fuel cell module DC voltage output V of the fuel cell module 202. FC The rate of change of is expressed as a measure of power per unit time (e.g., kilowatts per second (kW / s), volts per second (V / s), or amperes per second (A / s)).

[0045] Additionally, for the depicted embodiment, controller 212 is also configured to receive data indicating a reference power level (as shown by line 216). The reference power level may be a desired power output of power source assembly 200, such as a net DC power output P discussed in more detail below. NET When the reference power level indicates the DC power output P of the fuel cell module FC Need to be higher or lower than the current fuel cell module DC power output P FC , the controller 212 may change the control signal 218 to the fuel cell DC / DC converter 210 to increase or decrease the fuel cell module DC power output P FC , thereby meeting the power demand indicated by the reference power level. However, the fuel cell module DC power output P FC The increase and / or decrease of the power can be carried out at a controlled rate to ensure that the fuel cell module DC power output P FC The rate of change of is low enough to prevent or minimize premature wear of the fuel cell module 202.

[0046] The control signal 218 may be data indicating the duty cycle of the power switch. The duty cycle is a measure of the "on" time of the power switch relative to the total cycle period. By adjusting the duty cycle, the controller 212 can effectively regulate the power output of the fuel cell DC / DC converter 210 to ensure that the load 220 receives the necessary power.

[0047] In this manner, it should be understood that the fuel cell DC / DC converter 210 is based on the fuel cell module DC power output P provided to the fuel cell DC / DC converter 210 from the fuel cell module 202. FC , a reference power level, and a slew rate factor of the fuel cell module 202. The slew rate factor may indicate a maximum allowable slew rate of the fuel cell module 202 without premature degradation or wear of the fuel cell module 202.

[0048] Thus, the fuel cell DC / DC converter 210 may be based on the amount of power output from the fuel cell module 202 rather than on the commanded net DC power output P NET (eg, load power) to control the fuel cell module 202 .

[0049] Still reference Figure 5 , the fuel cell module 202 and the fuel cell DC / DC converter 210 are also electrically connected to the DC bus 206 to provide a regulated fuel cell module 202 power output P1 to the DC bus 206. In addition, for the illustrated embodiment, the battery DC / DC converter 208 and the battery module 204 are electrically connected in parallel with the fuel cell DC / DC converter 210 and the fuel cell module 202 to jointly provide a net DC power output P1 to the DC bus 206. NET .

[0050] In this manner, it should be appreciated that the controller 212 and the fuel cell DC / DC converter 210 may be used to control the fuel cell module 202 to react to changes in the reference power level of the power source assembly 200 without exceeding the slew rate range of the fuel cell module 202. To ensure that the power output demand (i.e., the net DC power output P NET At a desired level), the battery module can provide instantaneous increases and decreases in its power to meet the rate of increase and decrease of propulsion or load power (220) limited by the closed loop response of the DC / DC converter (208). In some embodiments, the DC / DC converter 208 can respond to load power changes in less than 10 milliseconds (ms), such as in less than 5 ms.

[0051] The DC bus 206 is also configured to provide a net DC power output P to the load 220. NET The load 220 may be, for example, an electric propeller of an aircraft vehicle (see, for example, Figure 2 and Figure 3 ). In this manner, it should be understood that the load 220 may include an inverter (not shown; for example, to convert the net DC power output P NET Converted to AC power output) and drive the propeller motor.

[0052] Reference now Figure 6 , a power source assembly 200 according to another exemplary aspect of the present disclosure is provided. Figure 6 The exemplary power source assembly 200 may be configured with Figure 5 The exemplary power source assembly 200 is constructed in a similar manner.

[0053] For example, Figure 6The exemplary power source assembly 200 generally includes a fuel cell module 202 configured to provide a fuel cell module DC power output P FC (and the fuel cell module DC voltage output V FC and the fuel cell module DC current output I FC ); battery module 204, which is configured to provide a battery DC power output P BAT (and the battery DC voltage output V BAT and battery DC current output I BAT ); a DC bus 206, which is configured to provide a net DC power output P to a load 220 NET ; battery DC / DC converter 208; and controller 212.

[0054] The battery DC / DC converter 208 is electrically connected in cascade with the battery module 204, and more specifically, is electrically connected in cascade directly with the battery module 304. However, for the depicted embodiment, the power source assembly 200 does not include a fuel cell DC / DC converter that is electrically connected in cascade directly with the fuel cell module 202, and instead, the power source assembly 200 includes a second DC / DC converter 222 that is electrically connected to the fuel cell module 202 and the battery DC / DC converter 208 for receiving electrical power from the fuel cell module 202 and the battery DC / DC converter 208. In particular, for the depicted embodiment, the battery DC / DC converter 208 (and the battery module 204) and the fuel cell module 202 are electrically connected in parallel with each other to provide electrical power to the second DC / DC converter 222.

[0055] In particular, for the depicted embodiment, the output terminals of the battery DC / DC converter 208 are electrically coupled to the output terminals of the fuel cell module 202 .

[0056] In addition, for Figure 6 In an embodiment, the controller 212 is operably coupled to the battery DC / DC converter 208 and is configured to receive a signal indicating the fuel cell module DC power output P FC (For example, the fuel cell module DC voltage output V FC 、Fuel cell module DC current output I FC , or both). Specifically, for the depicted embodiment, the battery DC / DC converter 208 is configured to receive data indicating the fuel cell module DC current output I FC data.

[0057] The controller 212 is configured to determine the DC power output P of the fuel cell module based on the received indication. FC200 to control the battery DC / DC converter 208 to maintain the slew rate from the fuel cell module 202 within the slew rate range of the fuel cell module 202. In this manner, it should be understood that the battery module 204 provides a sufficient amount of power in response to the increased electrical power demand from the power source assembly 200 to ensure that any changes in the power output from the fuel cell module 202 do not exceed the slew rate range of the fuel cell module 200.

[0058] Additionally, alternatively, it should be appreciated that the battery module 204 is configured to absorb a sufficient amount of power from the fuel cell module 202 in response to a reduced electrical power demand from the power source assembly 200 to ensure that the power output from the fuel cell module 202 does not exceed the slew rate range of the fuel cell module 202. Such a configuration may limit the rate at which the output power of the fuel cell module 202 may rise and fall.

[0059] Now briefly refer to Figure 7 , a graph 300 depicting the partitioning of net output power of a power source assembly is provided according to an exemplary aspect of the present disclosure. Figure 7 The exemplary power source components shown in the graph of can be the power source components described herein (such as Figure 5 The power source component 200 or Figure 6 One or more of the power source components 200).

[0060] Figure 7 The graph of 300 depicts time units (and more specifically, seconds) on the x-axis 302 and power output (and more specifically, kilowatts) on the y-axis 304. Fuel cell module DC power output P FC As indicated by line 306, the battery DC power output P BAT Indicated by line 308, and the net DC power output P NET Indicated by line 310 .

[0061] At time equal to zero seconds, the net DC power output is 200 kW. At time equal to zero seconds, the fuel cell module 202 provides substantially 100% of the net DC power output (ie, the fuel cell module DC power output P FC is equal to 200kW, and the battery DC power output P BAT equal to 0kW).

[0062] At time 1 second, the reference power level of the power source assembly 200 increases from the first power level (200 kW) to the second power level (850 kW). At time 1 second, the power output of the fuel cell module 202 remains at the first power level (200 kW), and the battery DC power output P BATThe power level of the power source assembly 200 is substantially instantaneously increased by an amount equal to the second power level minus the first power level (ie, from 0 kW to 650 kW), thereby allowing the net DC power output P of the power source assembly 200 to be NET Meet the reference power level requirements.

[0063] As the time increases from 1 second to 14 seconds, the DC power output P of the fuel cell module FC The power level gradually increases from the first power level to the second power level (200 kW to 850 kW), while the battery DC power output P BAT From an initial level (equal to the second power level minus the first power level; 650 kW) to 0 kW. As will be appreciated, the slew rate of the fuel cell module is graphically shown from time equal to 0 to time equal to 14 seconds, with a slew rate of 50 kW / s (650 kW divided by 13 seconds).

[0064] This configuration may allow the power source assembly to provide a continuous power output without prematurely wearing or degrading the fuel cell module in response to an increase in the reference power level demand on the power source assembly. In addition, this configuration may allow for significantly smaller capacity battery modules because the battery modules may only need to provide power during power changes in the propulsion system. As an example, when the propulsion power increases by 650kW in 100ms, a propulsion power system rated at 1MW may only require a 17kWh battery to regulate the voltage of the DC bus 206, where the voltage drop of a 3mF capacitor on the DC bus 206 is only 2%.

[0065] Still reference Figure 7 , it should be understood that, in further exemplary aspects, when the reference power level required by the power source assembly 200 may be reduced, the power "output" of the battery module can be negative so that it can receive electrical power from the fuel cell module to essentially instantaneously accommodate the required reduction in the reference power level requirement of the power source assembly while allowing the fuel cell module to more slowly drop to the required power level.

[0066] In particular, at a later time, such as at time equal to 100 seconds, as shown by interrupt 314, the net DC power output is 850 kW. At time equal to 100 seconds, the fuel cell module 202 provides substantially 100% of the net DC power output (i.e., the fuel cell module DC power output P FC =850kW, and the battery DC power output P BAT equal to 0kW).

[0067] At time 101 seconds, the reference power level of the power source assembly 200 is reduced from the third power level (850 kW) to the fourth power level (400 kW). At time 101 seconds, the power output of the fuel cell module 202 is maintained at the third power level (850 kW), and the battery DC power output P BAT The power source assembly 200 is substantially instantaneously reduced by an amount equal to the fourth power level minus the third power level (ie, from 0 kW to -450 kW) to allow the net DC power output P of the power source assembly 200 to be NET The reference power level requirement is met. In this manner, it will be appreciated that the battery module 204 can absorb 450 kW, effectively charging the battery module 204 .

[0068] As the time increases from 101 seconds to 110 seconds, the DC power output P of the fuel cell module FC The power level is gradually reduced from the third power level to the fourth power level (850 kW to 400 kW), while the amount of power absorbed by the battery module 204 is reduced from the initial level (equal to the fourth power level minus the third power level; -400 kW) to 0 kW. As will be appreciated, the slew rate of the fuel cell module is graphically shown from time equal to 101 seconds to time equal to 110 seconds, with a slew rate of 50 kW / s.

[0069] This configuration can allow the power source assembly to provide a continuous power output without causing premature wear or degradation of the fuel cell module in response to a reduction in the reference power level demand on the power source assembly. In addition, this configuration can allow the battery module 204 to be recharged during the transition period, thereby further reducing the necessary size of the battery module 204.

[0070] Reference now Figure 8 , a power source assembly 400 according to another exemplary aspect of the present disclosure is provided. Figure 8 The exemplary power source assembly 400 may be similar to that described above with reference to Figures 1 to 7 One or more of the described exemplary embodiments may be configured in a similar manner.

[0071] More specifically, for Figure 8 In the embodiment, the power source assembly 400 is similar to the above reference Figure 5 Thus, exemplary power source assembly 400 generally includes fuel cell module 402 , battery module 404 , battery DC / DC converter 408 , fuel cell DC / DC converter 410 , controller 412 , and DC bus 406 .

[0072] However, for the depicted embodiment, the fuel cell module 402, the battery module 404, the battery DC / DC converter 408, the controller 412, the fuel cell DC / DC converter 410, and the DC bus 406 together form a first power assembly 450, and the power source assembly 400 also includes a second power assembly 452. The second power assembly 452 is constructed in substantially the same manner as the first power assembly 450. Therefore, it should be understood that the second power assembly 452 also includes a fuel cell module 402', a battery module 404', a battery DC / DC converter 408', a controller 412', a fuel cell DC / DC converter 410', and a DC bus 406'. The second power assembly 452 can be constructed in substantially the same manner as the first power assembly 450, and can operate in substantially the same manner as the first power assembly 450. Therefore, the components of the second power assembly 452 can also be configured in the same manner as the above referenced embodiments. Figure 5 The components of the power source assembly 200 are constructed in the same manner as described.

[0073] However, for Figure 8 In an embodiment of the present invention, the power source assembly 450 includes redundancy benefits. In particular, the second power assembly 452 provides redundancy for the first power assembly 450. Therefore, it should be understood that the DC bus 406 of the first power assembly 450 includes a switch 454 to selectively electrically connect or disconnect the first power assembly 450 with the load 420, and similarly, the DC bus 406' of the second power assembly 452 includes a switch 455 to selectively electrically connect or disconnect the second power assembly 452 with the load 420.

[0074] In this manner, in the event that the first power assembly 450 fails, the second power assembly 452 can be connected to the load 420 to ensure that the load 420 continues to receive electrical power during the fault condition.

[0075] Additionally, alternatively, each of the first power assembly 450 and the second power assembly 452 can be configured to provide less than 100% of the expected maximum power draw requested by the load 420, such that during normal operating conditions (e.g., high power operating conditions), both the first power assembly 450 and the second power assembly 452 provide electrical power to the load 420. With such a configuration, in the event that one of the first power assembly 450 or the second power assembly 452 fails, the other of the first power assembly 450 or the second power assembly 452 can ensure that the load 220 is able to receive at least some electrical power during the fault state.

[0076] In addition, if Figure 8As shown by the dashed lines in FIG. 4 , the first power assembly 450 may alternatively include switches located at 454-1 (dedicated to the fuel cell module 402) and / or at 454-2 (dedicated to the battery module 404). This configuration may allow one of the fuel cell module 402 or the battery module 404 to contribute to the operation of the power source assembly 400 in the event of a failure of the other. Similarly, as shown in FIG. Figure 8 As shown in dashed lines in FIG. 4 , the second power assembly 452 may alternatively include switches located at 455-1 (dedicated to the fuel cell module 402') and / or 455-2 (dedicated to the battery module 404'). This configuration may similarly allow one of the fuel cell module 402' or the battery module 404' to contribute to the operation of the power source assembly 400 in the event of a failure of the other.

[0077] In addition, now refer to Fig. 9 , a power source assembly 400 according to yet another exemplary embodiment of the present disclosure is provided. Fig. 9 The exemplary power source assembly 400 is provided with Figure 8 The exemplary power source assembly 400 is constructed in substantially the same manner. However, for Fig. 9 In the embodiment of the present invention, the load 420 includes a first inverter 458 electrically coupled to the DC bus 406 of the first power assembly 450 and a second inverter 460 electrically coupled to the DC bus 406' of the second power assembly 452. The motor 462 of the load 420 can be configured to receive AC power from the first inverter 458, the second inverter 460, or both.

[0078] Fig. 9 The power source assembly 400 can be used with Figure 8 The power source assembly 400 operates in substantially the same manner, but may also provide redundancy in the load 220 by including dedicated inverters 458, 460 for the first power assembly 450 and the second power assembly 452, respectively.

[0079] Reference now Fig.10 , a schematic diagram of a power source assembly 500 according to yet another exemplary embodiment of the present disclosure is provided. Fig.10 The exemplary power source assembly 500 may be configured in a similar manner as one or more of the power source assemblies 200 , 400 described above.

[0080] For example, Fig.10 The exemplary power source assembly 500 generally includes a fuel cell module 502 configured to provide a fuel cell module DC power output P FC ; Battery module 504, which is configured to provide a battery DC power output P BATDC bus 506, which is configured to provide a net DC power output P to the load 520 NET ; a fuel cell DC / DC converter 510 electrically connected to the DC bus 506; and a controller 512 operably coupled to the fuel cell DC / DC converter 510. More specifically, for the depicted embodiment, the fuel cell DC / DC converter 510 is directly cascade electrically connected to the fuel cell module 502, and the controller 512 is configured to control the fuel cell DC / DC converter 510 based on the received data indicating the first DC power output to maintain the slew rate from the fuel cell module 502 within the slew rate range of the fuel cell module 501.

[0081] However, for Fig.10 In an embodiment, the power source assembly 500 includes a structure that introduces redundancy for the fuel cell module 502. Specifically, the fuel cell module 502 is a first fuel cell module 502A, the fuel cell DC / DC converter 510 is a first fuel cell DC / DC converter 510A, and the controller 512 is a first controller 512A. The power source assembly 500 also includes: a second fuel cell module 502B; a second fuel cell DC / DC converter 510B, which is arranged to be cascaded electrically connected to the second fuel cell module 502B; and a second controller 512B, which is operably connected to the second fuel cell DC / DC converter 510B and is configured to output a second fuel cell module DC power P from the second fuel cell module 502B based on the received indication. FC 2 to control the second fuel cell DC / DC converter 510B to maintain the slew rate from the second fuel cell module 502B within the slew rate range of the second fuel cell module 502B.

[0082] The power source assembly 500 also includes a first switch 530 downstream of the first fuel cell DC / DC converter 510A and a second switch 532 downstream of the second fuel cell DC / DC converter 510B. In this manner, the power source assembly 500 can electrically connect or disconnect the first fuel cell module 502A / first fuel cell DC / DC converter 510A from the DC bus 506 in response to, for example, a fault condition of one or more components of the power source assembly 500, and similarly, can selectively electrically connect or disconnect the second fuel cell module 502B / second fuel cell DC / DC converter 510B from the DC bus 506.

[0083] In short, it should also be understood that the power source assembly 500 also includes a battery module 504 and a battery DC / DC converter 508. The battery module 504 and the battery DC / DC converter 508 can provide the same as the above reference, for example Figure 5 and Figure 7 The battery module 204 and the battery DC / DC converter 208 have the same functionality as depicted.

[0084] As described above, the various power source components 200, 400, 500 of the present disclosure may include one or more controllers 212, 412, 412', 512A, 512B configured to receive data and, for example, make control decisions for the respective power source components 200, 400, 500 based on the received data.

[0085] In one or more exemplary embodiments, one or more controllers 212, 412, 412', 512A, 512B of the present disclosure may be independent controllers for the power source assembly 200, 400, 500, or alternatively, may be integrated into one or more of a controller for a vehicle integrated with the power source assembly 200, 400, 500, a controller for a thruster, and the like.

[0086] Furthermore, it should be understood that although Figure 8 The embodiments include the above reference Figure 5 The power source assembly 400 is constructed in a similar manner to the exemplary power source assembly 200 described above, but in other embodiments, the power source assembly 400 may alternatively be constructed in a similar manner to the exemplary power source assembly 200 described above. Figure 6 200 (eg, the first power assembly 450 and the second power assembly 452 may each be configured in a manner similar to that of the exemplary power source assembly 200 of FIG. 20 (eg, the first power assembly 450 and the second power assembly 452 may each be configured in a manner similar to that of FIG. 200 ). Figure 6 The components of the exemplary power source assembly 200 are constructed in the same manner, up to the DC bus 206).

[0087] Furthermore, it should be understood that although Fig. 9 The embodiments include the above reference Figure 5 The power source assembly 400 is constructed in a similar manner to the exemplary power source assembly 200 described above, but in other embodiments, the power source assembly 400 may alternatively be constructed in a similar manner to the exemplary power source assembly 200 described above. Figure 6 200 (eg, the first power assembly 450 and the second power assembly 452 may each be configured in a manner similar to that of the exemplary power source assembly 200 of FIG. 20 (eg, the first power assembly 450 and the second power assembly 452 may each be configured in a manner similar to that of FIG. 200 ). Figure 6 The components of the exemplary power source assembly 200 are constructed in the same manner, up to the DC bus 206).

[0088] Furthermore, it should be understood that although Figures 8 to 10 Two redundant fuel cell modules and battery module groups are each disclosed, but in other exemplary embodiments, the power source assembly may include any suitable number of redundant fuel cell modules and battery module groups (e.g., 3, 4, 5, 6, 7, 8, or up to 10).

[0089] Special References Fig.11 , the operation of the controller 600 will be described, and the controller 600 can be one or more of the controllers 212, 412, 412', 512A, 512B. In at least some embodiments, the controller 600 may include one or more computing devices 602. The computing device 602 may include one or more processors 602A and one or more memory devices 602B. The one or more processors 602A may include any suitable processing device, such as a microprocessor, a microcontroller, an integrated circuit, a logic device, and / or other suitable processing device. The one or more memory devices 602B may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, a hard drive, a flash drive, and / or other memory devices.

[0090] One or more memory devices 602B can store information accessible by one or more processors 602A, including computer-readable instructions 602C that can be executed by one or more processors 602A. Instructions 602C can be any instruction set that causes one or more processors 602A to operate when executed by one or more processors 602A. In some embodiments, instructions 602C can be executed by one or more processors 602A to cause one or more processors 602A to operate, such as any operation and function that the controller 600 and / or computing device 602 are constructed for, such as the operation for operating the power source assembly 200, 400, 500 described herein, and / or any other operation or function of one or more computing devices 602. Instructions 602C can be software written in any suitable programming language or can be implemented in hardware. Additionally and / or alternatively, instructions 602C can be executed in logically and / or virtually separated threads on one or more processors 602A. One or more memory devices 602B can also store data 602D that can be accessed by one or more processors 602A. For example, data 602D may include data indicative of power flow, data indicative of engine / aircraft operating conditions, and / or any other data and / or information described herein.

[0091] The computing device 602 may also include a network interface 602E for communicating, for example, with other components of the power source assembly 200, 400, 500, a vehicle containing the power source assembly 200, 400, 500, and the like. For example, in the depicted embodiment, as described above, the power source assembly 200, 400, 500 includes one or more sensors for sensing data indicating one or more parameters (e.g., power level, current level, voltage). The controller 600 is operably coupled to the one or more sensors via, for example, a network interface, so that the controller 600 can receive data indicating various operating parameters sensed by the one or more sensors during operation. In this way, the controller 600 can be configured to operate the power source assembly 200, 400, 500 in response to, for example, data sensed by the one or more sensors.

[0092] Network interface 602E may include any suitable components for interfacing with one or more networks, including, for example, a transmitter, a receiver, a port, a controller, an antenna, and / or other suitable components.

[0093] The techniques discussed herein refer to computer-based systems, actions taken by computer-based systems, information sent to computer-based systems, and information sent from computer-based systems. It will be appreciated by those of ordinary skill in the art that the inherent flexibility of computer-based systems allows for a variety of possible configurations, combinations, and divisions of tasks and functions between and within components. For example, the processing discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memories, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

[0094] Reference now Fig.12 It should be understood that the present disclosure may also provide a method 700 for operating a power source assembly for an aircraft vehicle. The method 700 may be similar to the method described above with reference to Figures 1 to 11 One or more of the power source assemblies described are used together.

[0095] In one exemplary aspect, method 700 includes providing a first DC power output from a fuel cell module at (702); providing a second DC power output from a battery module at (704); and receiving the first DC power output or the second DC power output using a DC / DC converter at (706).

[0096] Fig.12The exemplary method 700 also includes receiving data indicating a first DC power output at (708); and controlling the DC / DC converter based on the received data indicating the first DC power output at (710) to maintain a slew rate from the fuel cell module within a slew rate range of the fuel cell module.

[0097] In at least some exemplary aspects, controlling the DC / DC converter based on the received data indicating the first DC power output to maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module at (710) may include receiving data indicating a reference power level above the first DC power output at (712); and increasing the first DC power output from the fuel cell module to the reference power level at a slew rate within the slew rate range of the fuel cell module at (714). According to such exemplary aspects, for example, when the first DC power output is increased at (714), the second DC power output may be equal to the difference between the reference power level and the first DC power output.

[0098] Additionally or alternatively, in at least some exemplary aspects, controlling the DC / DC converter based on the received data indicating the first DC power output at (710) to maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module may include receiving data indicating a reference power level lower than the first DC power output at (716); and reducing the first DC power output from the fuel cell module to the reference power level at a slew rate within the slew rate range of the fuel cell module at (718). According to such exemplary aspects, for example, when the first DC power output is reduced at (718), the second DC power output can be equal to the difference between the reference power level and the first DC power output. For example, in some exemplary aspects, the second DC power output can be a negative power output.

[0099] It should be understood that if the fuel cell system directly provides power to the propulsion inverter without an auxiliary energy storage system (AESS) (such as a battery), the sudden power demand of the propulsion system during flight may have an impact on the reliability and life of the fuel cell system, because fuel cell systems are generally suitable for operation under constant load current or under conditions where the fuel cell load current changes very slowly (on the order of seconds). If the PEMFC is subjected to sudden load current changes, the catalyst in the membrane electrode assembly (MEA) may dissolve, and depending on the magnitude of the sudden load change, a low reactant state may also occur, both of which will shorten the life of the PEMFC. The architecture and control of the present disclosure minimize the size of the battery when combined with the fuel cell system without compromising the reliability and life of the fuel cell by slowing the reaction speed of the fuel cell to propulsion power changes. They also enable tight voltage regulation of the DC bus at the input of the propulsion inverter. Figure 8 , Fig. 9 , Fig.10 The embodiments in further provide improved fault tolerance through redundancy of electrical power system components.

[0100] Further aspects are provided by the subject matter of the following clauses:

[0101] A power source assembly for an aircraft vehicle, the power source assembly comprising: a fuel cell module, the fuel cell module being configured to provide a first DC power output; a battery module, the battery module being configured to provide a second DC power output; a DC bus, the DC bus being configured to provide a net DC power output to a load; a DC / DC converter, the DC / DC converter being electrically connected to the DC bus, the DC / DC converter being configured to receive the first DC power output from the fuel cell module or the second DC power output from the battery module; and a controller, the controller being operably connected to the DC / DC converter and being configured to receive data indicating the first DC power output, the controller being configured to control the DC / DC converter based on the data indicating the first DC power output to maintain a slew rate from the fuel cell module within a slew rate range of the fuel cell module.

[0102] A power source assembly as claimed in any preceding clause, wherein the controller is configured to receive data indicative of the first DC power output from a location between the fuel cell module and the DC / DC converter.

[0103] A power source assembly as described in any preceding clause, wherein the controller is further configured to receive data indicating a reference power level, and wherein the controller is configured to control the DC / DC converter based on the data indicating the reference power level, the data indicating the first DC power output, and a slew rate factor of the fuel cell module.

[0104] A power source assembly as described in any preceding clause, wherein the data indicative of the first DC power output is a current output from the fuel cell module, a voltage output from the fuel cell module, or both.

[0105] A power source assembly as claimed in any preceding clause, wherein the DC / DC converter is electrically connected in cascade with the fuel cell module.

[0106] A power source assembly as described in any preceding clause, wherein the DC / DC converter is a unidirectional DC / DC converter.

[0107] A power source assembly according to any preceding clause, wherein the DC / DC converter is a first DC / DC converter, and wherein the power source assembly further comprises: a second DC / DC converter, the second DC / DC converter being electrically connected in cascade with the battery module.

[0108] A power source assembly as described in any preceding clause, wherein the second DC / DC converter and the battery module are electrically connected in parallel with the first DC / DC converter and the fuel cell module to provide the net DC power output to the DC bus.

[0109] A power source assembly as claimed in any preceding clause, wherein the DC / DC converter is electrically connected in cascade with the battery module.

[0110] A power source assembly as described in any preceding clause, wherein the data indicative of the first DC power output is a current output from the fuel cell module, and wherein the DC / DC converter is constructed to control the output current from the battery module to control the current from the fuel cell module and maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module.

[0111] A power source assembly according to any preceding clause, wherein the DC / DC converter is a first DC / DC converter, and wherein the power source assembly further comprises: a second DC / DC converter, the second DC / DC converter being cascade-connected electrically to the fuel cell module.

[0112] A power source assembly as described in any preceding clause, wherein the first DC / DC converter, the battery module and the fuel cell module are electrically connected in parallel with the second DC / DC converter.

[0113] A power source assembly according to any of the preceding clauses, wherein the fuel cell module, the battery module, the DC / DC converter and the DC bus together form a first power assembly, and wherein the power source assembly further includes a second power assembly, the second power assembly including: a second fuel cell module; a second battery module; a second DC bus; and a second DC / DC converter, the second DC / DC converter being electrically connected to the second DC bus, or the second DC / DC converter being constructed to receive a DC power output from the second fuel cell module or from the second battery module; wherein the load includes an inverter and an electric motor constructed to receive AC power from the inverter, wherein the inverter is electrically connected to the DC bus of the first power assembly and the second DC bus of the second power assembly.

[0114] A power source assembly according to any of the preceding clauses, wherein the fuel cell module, the battery module, the DC / DC converter and the DC bus together form a first power assembly, and wherein the power source assembly further includes a second power assembly, the second power assembly including: a second fuel cell module; a second battery module; a second DC bus; and a second DC / DC converter, the second DC / DC converter being electrically connected to the second fuel cell module or the second battery module, the second DC / DC converter being constructed to receive a DC power output from the second fuel cell module or from the second battery module; wherein the load includes a first inverter electrically connected to the DC bus of the first power assembly, a second inverter electrically connected to the second DC bus, and an electric motor constructed to receive AC power from the first inverter, the second inverter or both.

[0115] A power source assembly according to any of the preceding clauses, wherein the fuel cell module is a first fuel cell module, wherein the DC / DC converter is a first DC / DC converter, and wherein the power source assembly further comprises: a second fuel cell module; a second DC / DC converter, the second DC / DC converter being electrically connected to the DC bus and being electrically connected in cascade with the second fuel cell module; the second DC / DC converter being electrically connected to the second fuel cell module and being configured to receive a DC power output from the second fuel cell module; wherein the second DC / DC converter and the second fuel cell module are electrically connected in parallel with the first DC / DC converter and the first fuel cell module.

[0116] A method for operating a power source assembly for an aircraft vehicle, the method comprising: providing a first DC power output from a fuel cell module; providing a second DC power output from a battery module; receiving the first DC power output or the second DC power output through a DC / DC converter; receiving data indicative of the first DC power output; and controlling the DC / DC converter based on the received data indicative of the first DC power output to maintain a slew rate from the fuel cell module within a slew rate range of the fuel cell module.

[0117] A method as described in any of the preceding clauses, wherein controlling the DC / DC converter based on received data indicating the first DC power output to maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module includes: receiving data indicating a reference power level higher than the first DC power output; and increasing the first DC power output from the fuel cell module to the reference power level at a slew rate within the slew rate range of the fuel cell module.

[0118] A method as in any preceding clause, wherein the second DC electrical power output is equal to a difference between the reference power level and the first DC electrical power output.

[0119] A method according to any preceding clause, wherein controlling the DC / DC converter based on received data indicating the first DC power output to maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module includes: receiving data indicating a reference power level lower than the first DC power output; and reducing the first DC power output from the fuel cell module to the reference power level at a slew rate within the slew rate range from the fuel cell module.

[0120] A method as in any preceding clause, wherein the second DC power output is a negative power output.

[0121] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any combined methods. The patentable scope of the present disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to fall within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. A power source assembly for an aircraft vehicle, characterized in that: The power source assembly comprises: a fuel cell module configured to provide a first direct current (DC) power output; a battery module configured to provide a second DC power output; a DC bus configured to provide a net DC power output to a load; a DC / DC converter electrically connected to the DC bus, the DC / DC converter being configured to receive the first DC power output from the fuel cell module or the second DC power output from the battery module; and a controller operably coupled to the DC / DC converter and configured to receive data indicative of the first DC power output, the controller configured to control the DC / DC converter based on the data indicative of the first DC power output to maintain a slew rate from the fuel cell module within a slew rate range of the fuel cell module.

2. The power source assembly according to claim 1, characterized in that: in, The controller is configured to receive data indicative of the first DC power output from a location between the fuel cell module and the DC / DC converter.

3. The power source assembly according to claim 2, characterized in that: in, The controller is further configured to receive data indicating a reference power level, and wherein the controller is configured to control the DC / DC converter based on the data indicating the reference power level, the data indicating the first DC power output, and a slew rate factor of the fuel cell module.

4. The power source assembly according to claim 3, characterized in that: in, The data indicative of the first DC power output is a current output from the fuel cell module, a voltage output from the fuel cell module, or both.

5. The power source assembly according to claim 2, characterized in that: in, The DC / DC converter is electrically connected to the fuel cell module in cascade.

6. The power source assembly according to claim 2, characterized in that: in, The DC / DC converter is a unidirectional DC / DC converter.

7. The power source assembly according to claim 2, characterized in that: in, The DC / DC converter is a first DC / DC converter, and wherein the power source assembly further comprises: A second DC / DC converter is electrically connected in cascade with the battery module.

8. The power source assembly according to claim 7, characterized in that: in, The second DC / DC converter and the battery module are electrically connected in parallel with the first DC / DC converter and the fuel cell module to provide the net DC power output to the DC bus.

9. The power source assembly according to claim 1, characterized in that: in, The DC / DC converter is electrically connected to the battery module in cascade.

10. The power source assembly according to claim 9, characterized in that: in, The data indicating the first DC power output is a current output from the fuel cell module, and wherein the DC / DC converter is constructed to control the output current from the battery module to control the current from the fuel cell module and maintain the slew rate from the fuel cell module within the slew rate range of the fuel cell module.

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