Method and apparatus for monitoring a fuel cell

Abstract

A torque generating system is described and includes a fuel cell power device, a high voltage battery, an electric drive unit, and a controller. The fuel cell power device has a non-linear power-temperature relationship having a local temperature maximum at a first electrical power level and a local temperature minimum at a second electrical power level. A first operating point of the fuel cell power device is less than the first electrical power level and a second operating point of the fuel cell power device is set at a third electrical power level greater than the first electrical power level, where the third electrical power level produces a fuel cell temperature less than the local temperature maximum. The fuel cell power device is controlled to one of the first operating point or the second operating point to transfer electrical power to the electric drive unit.

Description

Technical Field

[0001] This invention relates to methods and apparatus for monitoring fuel cells. Background Technology

[0002] A fuel cell is an electrochemical device that converts the chemical energy of a fuel (e.g., hydrogen) into electrical power through an electrochemical reaction. Multiple fuel cells can be combined to form a fuel cell stack, thereby producing the desired fuel cell power output. One type of fuel cell includes a polymer electrolyte membrane fuel cell (PEMFC). The electrical power generated by the fuel cell stack can be used to power electric motors, such as vehicle traction motors or stationary generators.

[0003] The operating temperature of a fuel cell stack can be negatively correlated with durability and service life, with higher average operating temperatures over time potentially reducing the service life of the fuel cell stack. Other factors that may affect the service life of a fuel cell stack include voltage cycling, peak voltage, and the presence of fuel contaminants.

[0004] The design, material selection, and integration of fuel cell stacks aim to optimize the trade-offs affecting performance, durability, and robustness to achieve power targets. The operation of fuel cell stacks needs to achieve power targets while simultaneously improving performance, service life, and robustness. Summary of the Invention

[0005] A torque generation system is described, comprising one or more fuel cell power units, one or more high-voltage batteries, one or more electric drive units, and a controller. The controller communicates with the one or more fuel cell power units, the one or more high-voltage batteries, and the one or more electric drive units to monitor and control the operation of the torque generation units to achieve a target torque output in response to a power request.

[0006] In one embodiment, the torque generation system includes a fuel cell power unit, a high-voltage battery, an electric drive unit, and a controller. The fuel cell power unit and the high-voltage battery are electrically connected to a high-voltage bus, and electrical power is supplied to the electric drive unit via the high-voltage bus. The fuel cell power unit has a nonlinear power-temperature relationship, which has a local temperature maximum at a first power level and a local temperature minimum at a second power level. A first operating point of the fuel cell power unit is less than the first power level, and a second operating point of the fuel cell power unit is set at a third power level greater than the first power level, wherein the third power level produces a fuel cell temperature less than the local temperature maximum. The fuel cell power unit is controlled to one of the first or second operating points to deliver electrical power to the electric drive unit, and the high-voltage battery and the fuel cell power unit cooperate to deliver electrical power to the electric drive unit, thereby generating mechanical torque in response to a power request.

[0007] Aspects of this disclosure include a second operating point of the fuel cell power device corresponding to a second electrical power level associated with a local temperature minimum.

[0008] Another aspect of this disclosure includes an electric drive unit that is an electric motor coupled to the vehicle's drivetrain, wherein a high-voltage battery and a fuel cell power unit cooperate to deliver electrical power to the electric motor, thereby generating traction torque in response to a power request.

[0009] Another aspect of this disclosure includes a high-voltage battery and a fuel cell power unit cooperating to deliver electrical power to an electric motor, thereby generating positive traction torque in response to a power request, including vehicle acceleration.

[0010] Another aspect of this disclosure includes a high-voltage battery and a fuel cell power unit cooperating to respond to torque, thereby generating electrical power via an electric motor to produce negative traction torque in response to a power request, including vehicle braking.

[0011] Another aspect of this disclosure includes an electric drive unit that is a motor coupled to a stationary electric motor, wherein a high-voltage battery and a fuel cell power unit cooperate to transfer electrical power to the motor, thereby generating mechanical torque in response to a power request.

[0012] Another aspect of this disclosure includes a fuel cell power unit being controlled to periodically alternate between a first operating point and a second operating point to deliver electrical power to an electrically driven unit of a torque generation system, thereby generating mechanical torque in response to a power request.

[0013] Another aspect of this disclosure includes a fuel cell power unit being controlled to alternate between a first operating point and a second operating point at a frequency and duty cycle in response to a power request.

[0014] Another aspect of this disclosure includes periodically controlling the fuel cell power unit between a first operating point and a second operating point to achieve an average power over time, which achieves an average operating temperature of the fuel cell power unit that is lower than a target operating temperature.

[0015] Another aspect of this disclosure includes a fuel cell power unit controlled to deliver electrical power to charge a high-voltage battery.

[0016] Another aspect of this disclosure includes a torque generation system comprising a first fuel cell power unit, a second fuel cell power unit, a high-voltage battery, an electric drive unit, and a controller. The first and second fuel cell power units and the high-voltage battery are electrically connected to a high-voltage bus, and electrical power is supplied to the electric drive unit via the high-voltage bus. Each of the first and second fuel cell power units has a nonlinear power-temperature relationship having a local temperature maximum at a first power level and a local temperature minimum at a second power level. A first operating point for each of the first and second fuel cell power units is less than the first power level. A second operating point for each of the fuel cell power units is set at a third power level greater than the first power level. The third power level corresponds to an operation where the fuel cell power unit generates a fuel cell temperature less than the local temperature maximum. The first fuel cell power unit is controlled to one of the first or second operating points to deliver electrical power to the electric drive unit. The second fuel cell power unit is controlled to one of the first or second operating points to deliver electrical power to the electric drive unit. The high-voltage battery, along with the first and second fuel cell power units, cooperate to deliver electrical power to the electric drive unit, thereby generating mechanical torque in response to power requests.

[0017] Another aspect of this disclosure includes: a first fuel cell power unit being controlled to a second operating point, while a second fuel cell power unit is controlled to a first operating point to deliver electrical power to an electric drive unit.

[0018] Another aspect of this disclosure includes controlling the first fuel cell power unit to one of a first operating point or a second operating point, and deactivating the second fuel cell power unit.

[0019] Another aspect of this disclosure includes a first fuel cell power unit and a second fuel cell power unit being controlled to periodically alternate between a first operating point and a second operating point to deliver electrical power to an electrically driven unit of a torque generation system, thereby generating mechanical torque in response to a power request.

[0020] Another aspect of this disclosure includes a first fuel cell power unit being controlled to alternate between a first operating point and a second operating point at a first frequency and a first duty cycle, and a second fuel cell power unit being controlled to alternate between a first operating point and a second operating point at a second frequency and a second duty cycle.

[0021] Another aspect of this disclosure includes a first frequency equal to a second frequency; and a phase difference of 180 degrees between the first frequency and the second frequency.

[0022] Another aspect of this disclosure includes a first frequency equal to a second frequency, wherein the first frequency and the second frequency are in phase.

[0023] Another aspect of this disclosure includes the first frequency being different from the second frequency.

[0024] Another aspect of this disclosure includes a method for controlling a fuel cell power unit, wherein the fuel cell power unit is electrically connected to a torque generation system. The method includes determining a nonlinear power-temperature relationship of the fuel cell power unit, including determining a local temperature maximum at a first power level and a local temperature minimum at a second power level. A first operating point of the fuel cell power unit below the first power level is determined, and a second operating point of the fuel cell power unit is set at a third power level above the first power level. The third power level produces a fuel cell temperature below the local temperature maximum. The fuel cell power unit is controlled to alternate between the first and second operating points to deliver electrical power to an electrically driven unit of the torque generation system, thereby generating mechanical torque.

[0025] Another aspect of this disclosure includes: determining a power request for the torque generation system; determining the magnitude of the battery power transferred between the torque generation system and the high-voltage battery; and controlling the fuel cell power unit to periodically alternate between a first operating point and a second operating point to transfer electrical power to the electric drive unit of the torque generation system. The magnitude of the battery power transferred between the torque generation system and the high-voltage battery is controlled based on the average electrical power transferred from the fuel cell power unit to the electric drive unit of the torque generation system in response to the power request.

[0026] This invention provides the following technical solutions:

[0027] 1. A torque generating system, comprising:

[0028] Fuel cell power unit, high-voltage battery, electric drive unit and controller;

[0029] The fuel cell power unit and the high-voltage battery are electrically connected to a high-voltage bus, and the electrical power is supplied to the electric drive unit via the high-voltage bus.

[0030] The fuel cell power device has a nonlinear power-temperature relationship, which has a local temperature maximum value at a first power level and a local temperature minimum value at a second power level.

[0031] Wherein, the first operating point of the fuel cell power device is less than the first electrical power level;

[0032] Wherein, the second operating point of the fuel cell power device is greater than the first power level and less than the third power level, wherein the third power level corresponds to the operation of the fuel cell power device that generates a fuel cell temperature less than the maximum local temperature.

[0033] The fuel cell power unit is controlled to either the first operating point or the second operating point to deliver electrical power to the electric drive unit; and

[0034] The high-voltage battery and the fuel cell power unit cooperate to transfer electrical power to the electric drive unit, thereby generating mechanical torque in response to power requests.

[0035] 2. The system according to Scheme 1, wherein the second operating point of the fuel cell power device corresponds to the second electrical power level associated with the local temperature minimum.

[0036] 3. The system according to claim 1, wherein the electric drive unit includes a motor coupled to the vehicle drivetrain; and wherein the high-voltage battery and the fuel cell power unit cooperate to deliver electrical power to the motor, thereby generating traction torque in response to the power request.

[0037] 4. The system according to claim 3, wherein the high-voltage battery and the fuel cell power unit cooperate to transfer electrical power to the motor, thereby generating a positive traction torque in response to the power request, wherein the power request includes a request for vehicle acceleration.

[0038] 5. The system according to claim 3, wherein the high-voltage battery and the fuel cell power unit cooperate to respond to torque, thereby generating electrical power through the motor to generate negative traction torque in response to the power request, wherein the power request includes a request for braking.

[0039] 6. The system according to claim 1, wherein the electric drive unit includes a motor coupled to a stationary electric motor; and wherein the high-voltage battery and the fuel cell power unit cooperate to transfer electrical power to the motor, thereby generating mechanical torque in response to the power request.

[0040] 7. The system according to claim 1, wherein controlling the fuel cell power device to one of the first operating point or the second operating point to deliver electrical power to the electric drive unit comprises: the fuel cell power device being controlled to periodically alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system, thereby generating mechanical torque in response to the power request.

[0041] 8. The system according to claim 7, wherein controlling the fuel cell power device to periodically alternate between the first operating point and the second operating point comprises: the fuel cell power device being controlled to alternate between the first operating point and the second operating point at a frequency and duty cycle in response to the power request.

[0042] 9. The system according to Scheme 7, wherein the fuel cell power unit is periodically controlled between the first operating point and the second operating point to achieve an average power over time, the average power achieving an average operating temperature of the fuel cell power unit that is less than a target operating temperature.

[0043] 10. The system according to claim 1, further comprising the fuel cell power unit being controlled to deliver electrical power to charge the high-voltage battery.

[0044] 11. A torque generating system, comprising:

[0045] The system comprises a first fuel cell power unit, a second fuel cell power unit, a high-voltage battery, an electric drive unit, and a controller.

[0046] The first fuel cell power unit, the second fuel cell power unit, and the high-voltage battery are electrically connected to a high-voltage bus, and the electrical power is supplied to the electric drive unit via the high-voltage bus.

[0047] Each of the first fuel cell power device and the second fuel cell power device has a nonlinear power-temperature relationship, which has a local temperature maximum value at a first power level and a local temperature minimum value at a second power level.

[0048] Wherein, the first operating point of each of the first fuel cell power device and the second fuel cell power device is less than the first power level, and wherein, the second operating point of each of the fuel cell power devices is greater than the first power level and occurs at a third power level, wherein, the third power level corresponds to the operation of the fuel cell power device that produces a fuel cell temperature less than the maximum local temperature.

[0049] The first fuel cell power unit is controlled to one of the first operating point or the second operating point to deliver electrical power to the electric drive unit.

[0050] The second fuel cell power unit is controlled to either the first or the second operating point to deliver electrical power to the electric drive unit; and

[0051] The high-voltage battery, along with the first and second fuel cell power units, cooperate to deliver electrical power to the electric drive unit, thereby generating mechanical torque in response to a power request.

[0052] 12. The system according to claim 11, comprising: a first fuel cell power unit being controlled to a second operating point, and a second fuel cell power unit being controlled to the first operating point to deliver electrical power to the electric drive unit.

[0053] 13. The system according to claim 11, comprising: the first fuel cell power unit being controlled to one of the first operating point or the second operating point, and the second fuel cell power unit being deactivated.

[0054] 14. The system according to claim 10, wherein controlling the first fuel cell power unit and the second fuel cell power unit to one of the first operating point or the second operating point to deliver electrical power to the electric drive unit comprises: the first fuel cell power unit and the second fuel cell power unit being controlled to periodically alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system, thereby generating mechanical torque in response to the power request.

[0055] 15. The system according to claim 14, wherein controlling the first fuel cell power device and the second fuel cell power device to periodically alternate between the first operating point and the second operating point comprises: the first fuel cell power device being controlled to alternate between the first operating point and the second operating point at a first frequency and a first duty cycle, and the second fuel cell power device being controlled to alternate between the first operating point and the second operating point at a second frequency and a second duty cycle.

[0056] 16. The system according to claim 15, wherein the first frequency is equal to the second frequency; and wherein the phase difference between the first frequency and the second frequency is 180 degrees.

[0057] 17. The system according to claim 15, wherein the first frequency is equal to the second frequency; and wherein the first frequency and the second frequency are in phase.

[0058] 18. The system according to claim 15, wherein the first frequency is different from the second frequency.

[0059] 19. A method for controlling a fuel cell power unit, wherein the fuel cell power unit is electrically connected to a torque generating system, the method comprising:

[0060] Determining the nonlinear power-temperature relationship of the fuel cell power device includes determining the maximum local temperature at a first power level and the minimum local temperature at a second power level.

[0061] Determine a first operating point for the fuel cell power device that is less than the first electrical power level;

[0062] The fuel cell power device is determined to be at a second operating point that is greater than the first power level and occurs at a third power level, wherein the third power level produces a fuel cell temperature that is less than the maximum local temperature.

[0063] The fuel cell power unit is controlled to alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system, thereby generating mechanical torque.

[0064] 20. The method according to claim 19 further includes:

[0065] Determine the power request for the torque generation system;

[0066] Determine the magnitude of the battery power transmitted between the torque generation system and the high-voltage battery;

[0067] The fuel cell power unit is controlled to periodically alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system; and

[0068] The magnitude of the battery power transmitted between the torque generation system and the high-voltage battery is controlled based on the average electrical power of the electric drive unit in response to the power request and transmitted by the fuel cell power unit to the torque generation system.

[0069] The above features and advantages of this teaching, as well as other features and advantages, will readily become apparent from the following detailed description of some of the best modes and other embodiments for carrying out this teaching as defined in the appended claims when understood in conjunction with the accompanying drawings. Attached Figure Description

[0070] One or more embodiments will now be described by way of example with reference to the accompanying drawings, wherein:

[0071] Figure 1 The schematic diagram illustrates the components of the architecture of a torque generation system according to the present disclosure, which includes a fuel cell power unit, a high-voltage battery and an electric drive unit, and an associated controller.

[0072] Figure 2A The diagram illustrates an embodiment of a nonlinear power-temperature relationship according to an embodiment of a fuel cell power device of the present disclosure, the nonlinear power-temperature relationship having a local temperature maximum at a first power level and a local temperature minimum at a second power level.

[0073] Figure 2B A further embodiment of a nonlinear power-temperature relationship according to an embodiment of a fuel cell power device of the present disclosure is illustrated, the nonlinear power-temperature relationship having a local temperature maximum at a first power level and a local temperature minimum at a second power level.

[0074] Figure 2C The diagram illustrates an embodiment of a nonlinear power-temperature relationship according to an embodiment of a fuel cell power device of the present disclosure, the nonlinear power-temperature relationship having multiple local temperature maxima and multiple local temperature minima.

[0075] Figure 3 A fuel cell temperature management routine for monitoring and controlling the operation of one or more fuel cell power devices employed in an embodiment of a torque generation system, according to the present disclosure, is illustrated schematically in flowchart form.

[0076] Figure 4AThe diagram illustrates the operation of an embodiment of a torque generation system including a single fuel cell power unit according to the present disclosure.

[0077] Figure 4B-4G The diagram illustrates the operation of an embodiment of a torque generation system including a dual fuel cell power unit according to the present disclosure.

[0078] Figure 5 The diagram illustrates temperature and power data associated with the operation of an embodiment of a torque generation system employing a fuel cell temperature management routine according to the present disclosure.

[0079] The accompanying drawings are not necessarily drawn to scale and may present slightly simplified representations of the various preferred features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes. Details associated with such features will be determined in part by the specific intended application and environment of use. Detailed Implementation

[0080] As described and illustrated herein, the components of the disclosed embodiments can be arranged and designed in a variety of different configurations. Therefore, the following detailed description is not intended to limit the scope of this disclosure as claimed, but only represents possible embodiments thereof. Furthermore, while numerous specific details are set forth in the following description to provide a thorough understanding of the embodiments disclosed herein, some embodiments may be practiced without some of these details. Moreover, for clarity, certain technical materials understood in the relevant art have not been described in detail to avoid unnecessarily obscuring this disclosure. Additionally, as illustrated and described herein, this disclosure may be practiced without elements not specifically disclosed herein.

[0081] The following detailed description is merely exemplary in nature and is not intended to limit application or use. Furthermore, it is not intended to be bound by any express or implied theory presented herein. Throughout the accompanying drawings, corresponding reference numerals indicate similar or corresponding parts and features. As used herein, the term "system" means, individually or in combination, a combination or collection of the following: mechanical and electronic hardware, software, firmware, electronic control components, processing logic and / or processor devices, including but not limited to: application-specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated, or grouped) executing one or more software or firmware programs, memory for containing software or firmware instructions, combinational logic circuits, and / or other suitable components providing the described functionality.

[0082] Consistent with the embodiments disclosed herein Figure 1The schematic illustration shows the components of an architecture for a torque generation system 100, including a single fuel cell power unit 20 or an array 22 of fuel cell power units 20, a high-voltage battery 10, an electric drive unit 50, an auxiliary power unit 60, and a controller 70. The torque generation system 100 is controllable to generate mechanical torque in response to a power request, wherein, as a non-limiting example, the power request may include an output torque request, an operator torque request, etc. One or more fuel cell power units 20 and high-voltage batteries 10 are electrically connected via a high-voltage bus 25 to a high-voltage power distribution system 30 to supply electrical power to the electric drive unit 50. One or more fuel cell power units 20 and high-voltage batteries 10 may be used as the DC power source for the electric drive unit 50. In one embodiment, the electric drive unit 50 may be a motor that can be employed on a mobile platform, i.e., a vehicle providing traction power, and may take the form of a commercial vehicle, industrial vehicle, agricultural vehicle, passenger vehicle, aircraft, ship, rail train, all-terrain vehicle, personal mobile device, robot, etc., to achieve the purposes of this disclosure. Alternatively, the electric drive unit 50 can be installed in non-vehicle applications, such as for stationary power generation, portable power generation, electronic devices, remote weather station operation, communication centers, etc. Individual fuel cell power units 20 are indicated by solid lines, and arrays 22 of fuel cell power units 20 are indicated by dashed lines. One of the fuel cell power units is indicated by the number 20', indicating that it has a different configuration and / or different performance characteristics than fuel cell power unit 20. Reference Figure 2A , Figure 2B and Figure 2C The following discussion will focus on details related to the performance characterization of fuel cell power units 20 and 20'. The concepts described herein are not limited to a specific number of fuel cell power units 20 that may be employed. Instead, the number of fuel cell power units 20 is determined based on system-specific requirements, including, for example, two, three, four, or more fuel cell power units 20. As a non-limiting example, in some embodiments, up to twenty or more fuel cell power units 20 may be employed, such as on a train locomotive.

[0083] In one embodiment, one or more fuel cell power units 20 and high-voltage battery 10 cooperate to supply electrical power to electric drive unit 50, controller 70 operates torque generation system 100, and high-voltage battery 10 is in a power consumption mode during the journey, such as when on-board torque generation system 100 is used and route planning and navigation routines (such as user mode learning, driver mode input, navigation route input, etc.) are employed. In another embodiment, fuel cell power unit 20 and high-voltage battery 10 cooperate to supply electrical power to electric drive unit 50, wherein when on-board torque generation system 100 is used, controller 70 operates torque generation system 100, and high-voltage battery 10 is in a power sustainment mode during the journey.

[0084] In one embodiment, together with an internal combustion engine, one or more fuel cell power units 20 and a high-voltage battery 10 cooperate to supply electrical power to an electric drive unit 50, wherein the internal combustion engine is used to generate traction torque transmitted to the vehicle drivetrain and / or generate torque that is converted into electrical power for use by the electric drive unit 50 and / or for use in the high-voltage battery 10.

[0085] In one embodiment, the electric drive unit 50 includes a rotary motor that functions as an electric traction motor for a system having at least a partial electric drivetrain and is coupled to the drive wheels via a drivetrain. Non-limiting examples of the rotary motor may include a permanent magnet DC motor, an AC motor, a DC generator, an AC generator, an eddy current clutch, an eddy current brake, a rotary converter, a hysteresis dynamometer, a transformer, etc. The motor torque generated by the rotary motor can be used to propel the vehicle, start the internal combustion engine (in such a system), and / or perform other electromechanical functions. The rotary motor may also be controlled to respond to torque and thus generate electrical power, such as for regenerative braking. The electric drive unit 50 may include a single motor that is coupled to the wheels via a drivetrain when used in a vehicle. Alternatively, the electric drive unit 50 may include multiple motors that are coupled to multiple wheels via one or more drivetrain devices.

[0086] In one embodiment, each fuel cell power unit 20 includes multiple polymer electrolyte membrane fuel cells (PEMFCs) and includes a cathode, an anode, and an electrolyte. The anode system may include a single-injector system or a multi-injector system fluidly coupled to the anode and arranged to controllably supply pressurized hydrogen from a hydrogen tank to the anode inlet. Each fuel cell power unit 20 may also include an air supply system including an air inlet and an exhaust outlet and arranged to supply and control an airflow to the cathode. The electrolyte (e.g., a polymer electrolyte membrane) is disposed between the cathode and the anode. Further, the fuel cell power unit 20 may be formed from one or more membrane electrode assemblies (MEAs) including a cathode, an anode, multiple flow plates, a catalyst, and multiple gas diffusion layers.

[0087] During operation of the fuel cell power unit 20, the chemical energy from the electrochemical reaction of hydrogen (H2) and oxygen (O2) can be converted into electrical energy. Specifically, hydrogen (H2) can enter the anode and be catalytically split into protons (H+) at the catalyst. + ) and electrons (e - Proton (H) + Electrons can permeate to the cathode through the electrolyte, while electrons (e) - The protons (H+) that permeate through the electrolyte may not permeate the cathode, but can instead travel along an external load circuit to the cathode to generate fuel cell power output or current. Simultaneously, air (e.g., oxygen (O2) and nitrogen (N2)) can enter the cathode and react with protons (H+) that permeate through the electrolyte. + ) and electrons (e) reaching the cathode from the electrically driven unit 50 - The reaction produces byproducts such as water (H2O) and heat. The heat can be expelled through the fuel cell and / or cooling fluid. Water (H2O) can travel through the electrolyte to the anode and can be collected in a storage tank. Each fuel cell power unit 20 exhibits a nonlinear power-temperature relationship, which is described with reference to Figure 2.

[0088] The controller 70 includes an executable control routine 300 for operating the torque generation system 100, and references herein to... Figure 3 To describe.

[0089] In one embodiment, the torque generation system 100 includes a high-voltage battery 10 and a single fuel cell power unit 20. Alternatively, in one embodiment, the torque generation system 100 includes a high-voltage battery 10, a fuel cell power unit 20, and a second of the fuel cell power units 20. In one embodiment, the arrangement may include one or more fuel cell power units 20'. Alternatively, in one embodiment, the torque generation system 100 includes an array 22 of high-voltage batteries 10 and fuel cell power units 20'.

[0090] Figure 2A The diagram illustrates the reference. Figure 1 The performance characterization 200 of an embodiment of the fuel cell power unit 20 is described. Performance characterization 200 can be described with respect to electrical power 201 on the horizontal axis and temperature 205 of the fuel cell power unit 200 on the vertical axis, wherein a nonlinear power-temperature relationship 210 is illustrated. The nonlinear power-temperature relationship 210 of the fuel cell power unit 20 can arise during product development due to system optimization, material selection, design trade-offs, etc., affecting performance, durability, and robustness in order to achieve electrical power targets.

[0091] Electrical power 201 can be a quantitative measure of the net electrical power output from the fuel cell power unit 20, and its range is between minimum or zero power output 202 and maximum power output 203. Maximum power output 203 indicates the maximum power output that the fuel cell power unit 20 is capable of producing. Temperature 205 of the fuel cell power unit 20 is a quantitative measure of the temperature (such as coolant inlet temperature or another parameter) associated with the operation of the fuel cell power unit 20. Temperature 205 ranges between a low temperature 206 (e.g., ambient temperature) and a maximum temperature 207 (e.g., that may occur when the fuel cell power unit 20 is operating at maximum power output).

[0092] The nonlinear power-temperature relationship 210 includes a first inflection point 211 occurring at a local temperature maximum 212, and has an associated first electrical power level 213. The nonlinear power-temperature relationship 210 also includes a second inflection point 215 occurring at a local temperature minimum 216, and has an associated second electrical power level 217.

[0093] The nonlinear power-temperature relationship 210 also includes a third operating point 218 and an associated third electrical power level 219, which occurs at a point on the nonlinear power-temperature relationship 210 at a power level greater than the second electrical power level 217, where the temperature is equal to the local temperature maximum 212.

[0094] The nonlinear power-temperature relationship 210 can be divided into a first operating region 220, a second operating region 230, and a third operating region 240. The first operating region 220 is defined as the region of the nonlinear power-temperature relationship 210 between zero power output and a first electrical power level 213. The second operating region 230 is defined as the region of the nonlinear power-temperature relationship 210 between the first electrical power level 213 and a third electrical power level 219. The third operating region 240 is defined as the region of the nonlinear power-temperature relationship 210 where the power output is greater than the third electrical power level 219. A first operating point 225(A) is indicated, representing the power level within the first operating region 220, i.e., less than the first electrical power level 213 of the fuel cell power unit 20. A second operating point 235(B) is also indicated, representing the power level within the second operating region 230, i.e., greater than the first electrical power level 213 and less than the third electrical power level 219.

[0095] Figure 2B The diagram illustrates the reference. Figure 1 The performance characterization 250 of an embodiment of the fuel cell power unit 20' is described. Performance characterization 250 can be described with respect to electrical power 201 on the horizontal axis and temperature 205 of the fuel cell power unit 20' on the vertical axis, wherein a nonlinear power-temperature relationship 260 is illustrated. The nonlinear power-temperature relationship 260 of the fuel cell power unit 20' can arise during product development due to system optimization, material selection, design trade-offs, etc., affecting performance, durability, and robustness in order to achieve electrical power targets.

[0096] The nonlinear power-temperature relationship 260 includes a first inflection point 261 occurring at a local temperature maximum 262, and has an associated first electrical power level 263. The nonlinear power-temperature relationship 260 also includes a second inflection point 265 occurring at a local temperature minimum 266, and has an associated second electrical power level 267.

[0097] The nonlinear power-temperature relationship 260 also includes a third operating point 268 and an associated third electrical power level 269, which occurs at a point on the nonlinear power-temperature relationship 260 at a power level greater than the second electrical power level 267, where the temperature is equal to the local temperature maximum 262.

[0098] The nonlinear power-temperature relationship 260 can be divided into a first operating region 270, a second operating region 280, and a third operating region 290. The first operating region 270 is defined as the region of the nonlinear power-temperature relationship 260 between zero power output 202 and a first electrical power level 263. The second operating region 280 is defined as the region of the nonlinear power-temperature relationship 260 between the first electrical power level 263 and a third electrical power level 269. The third operating region 290 is defined as the region of the nonlinear power-temperature relationship 260 where the power output is greater than the third electrical power level 269. A first operating point 275(A) is indicated, representing the power level within the first operating region 270, i.e., less than the first electrical power level 263 of the fuel cell power unit 20'. A second operating point 285(B) is also indicated, representing the power level within the second operating region 280, i.e., greater than the first electrical power level 263 and less than the third electrical power level 269.

[0099] Performance characterization 250 of an embodiment of fuel cell power device 20' and reference Figure 2A The performance characterization 200 of the described embodiments of the fuel cell power unit 20 differs in the power levels and temperatures associated with the maximum and minimum points. This may lead to control differences related to the power demand and utilization of fuel cell power unit 20 and fuel cell power unit 20'.

[0100] In one embodiment, performance characterization 250 represents a characterization of an embodiment of the fuel cell power unit 20 after a period of operation in use.

[0101] In one embodiment, performance characterization 250 represents a characterization of another configuration of the fuel cell power unit 20' after the operating period in use.

[0102] Figure 2C The diagram illustrates the reference. Figure 1 Another performance characterization 600 of an embodiment of the described fuel cell power unit 20'. Performance characterization 600 includes a nonlinear power-temperature relationship 610 having multiple local temperature maxima and multiple local temperature minima. Performance characterization 600 can be described with respect to electrical power 601 on the horizontal axis and temperature 605 of the fuel cell power unit 20' on the vertical axis, wherein the nonlinear power-temperature relationship 610 is illustrated. Electrical power 601 ranges between minimum or zero power output 602 and maximum power output 603. Temperature 605 ranges between a low temperature 606 (e.g., ambient temperature) and a maximum temperature 607 (e.g., which may occur when the fuel cell power unit 20 operates at maximum power output).

[0103] The nonlinear power-temperature relationship 610 of the fuel cell power unit 20' may arise during product development due to system optimization, material selection, design trade-offs, etc., that affect performance, durability, and robustness in order to achieve the electric power target.

[0104] The nonlinear power-temperature relationship 610 includes a first maximum point 611 occurring at a local temperature maximum 612, and has an associated first electrical power level 625. The nonlinear power-temperature relationship 610 also includes a first minimum point 615 occurring at a local temperature minimum 616, and has an associated second electrical power level. The nonlinear power-temperature relationship 610 includes a second maximum point 617 occurring at the local temperature maximum 612, and has an associated second electrical power level 635. The nonlinear power-temperature relationship 610 also includes a second minimum point 619 occurring at the local temperature minimum 616, and has an associated second electrical power level. The nonlinear power-temperature relationship 610 also includes a third operating point and an associated third electrical power level 645, which occurs at a point on the nonlinear power-temperature relationship 610 at a power level where the temperature is equal to the local temperature maximum 612.

[0105] The nonlinear power-temperature relationship 610 can be divided into a first operating region 620, a second operating region 630, a third operating region 640, and a fourth operating region 650. The first operating region 620 is defined as the region of the nonlinear power-temperature relationship 610 between zero power output 602 and a first power level 625. The second operating region 630 is defined as the region of the nonlinear power-temperature relationship 610 between the first power level 625 and the second power level 635. The third operating region 640 is defined as the region of the nonlinear power-temperature relationship 610 where the power output is between the second power level 635 and the third power level 645. The fourth operating region 650 is defined as the region of the nonlinear power-temperature relationship 610 where the power output is greater than the third power level 645.

[0106] The term "controller" and related terms (such as microcontroller, control module, module, control, control unit, processor, and similar terms) refer to one or more combinations of: application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), electronic circuits, central processing units, such as microprocessors, and associated non-transitory memory components (read-only, programmable read-only, random access, hard disk drives, etc.) in the form of high-speed clocks and memory / storage devices. Non-transitory memory components are capable of storing machine-readable instructions in the following forms: one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices, signal conditioning and buffering circuits, and other components accessible by one or more processors to provide the described functionality. Input / output circuits and devices include analog-to-digital converters and related devices that monitor inputs from sensors, wherein such inputs are monitored at a preset sampling frequency or in response to a triggering event. Software, firmware, program, instructions, control routines, code, algorithms, and similar terms mean a set of instructions executable by the controller, including calibration and lookup tables. Each controller executes control routines to provide the desired functionality. Routines can be executed at periodic intervals during ongoing operation. Alternatively, routines can be executed in response to the occurrence of a triggering event. Communication between the controller, actuator, and / or sensor can be achieved using a direct wired point-to-point link, a networked communication bus link, a wireless link, or another suitable communication link. Communication includes exchanging data signals in a suitable form, including, for example, electrical signals via a conductive medium, electromagnetic signals via air, optical signals via optical waveguides, etc. Data signals may include discrete, analog, or digitized analog signals representing inputs from sensors, actuator commands, and communication between the controller.

[0107] The term "signal" refers to a physically identifiable indicator that conveys information and can be a suitable waveform (e.g., electrical, optical, magnetic, mechanical, or electromagnetic) capable of traveling through a medium, such as DC, AC, sine wave, triangle wave, square wave, vibration, etc.

[0108] The terms “calibration,” “calibrated,” and related terms refer to the result or process of comparing an actual or standard measurement associated with a device or system with a sensed or observed measurement or command position of that device or system. Calibration as described herein can be reduced to a storable table of parameters, multiple executable equations, or may take another suitable form as part of a measurement or control routine.

[0109] A parameter is defined as a measurable quantity that represents a physical property of a device or other component, which can be identified using one or more sensors and / or a physical model. A parameter can have discrete values, such as "1" or "0", or it can be an infinite variable in terms of value.

[0110] Figure 3 An embodiment of a fuel cell temperature management routine ('control routine') 300 is schematically illustrated, which is used to monitor and control the temperature at a reference temperature. Figure 1 The described embodiment of the torque generation system 100 (with a high-voltage battery 10) employs the operation of a fuel cell power unit 20 or an array 22 of fuel cell power units 20. When an array 22 of fuel cell power units 20 is employed, one or more of the fuel cell power units 20 may have a performance characterization 200 (such as, reference to...). Figure 2A (As described), one or more of the fuel cell power units may have performance characteristics 250 (such as, reference 250). Figure 2B The described), and / or one or more of the fuel cell power devices may have performance characterizations 600 (such as, reference ). Figure 2C (Described). Control routine 300 is designed for (multiple) corresponding embodiments of fuel cell power devices 20, 20', and is respectively referenced in the reference. Figure 2A , Figure 2B and / or Figure 2C The description describes one or more of the nonlinear power-temperature relationships 210, 260, and / or 610 associated with the corresponding performance characteristics 200, 250, and / or 600. In one embodiment, and as described herein, control routine 300 describes the operation of a torque generation system 100 comprising (multiple) fuel cell power units 20 and electric drive units 50 when deployed in a vehicle. Control routine 300 is illustrated as a set of blocks in a logic flowchart representing a sequence of operations that can be implemented in hardware, software, or a combination thereof. In the context of software, the blocks represent computer instructions that, when executed by one or more processors, perform the described operations. Table 1 is provided as a notation, in which the numbered blocks and their corresponding functions are described below, corresponding to control routine 300.

[0111] Table 1

[0112] box Box content 301 Operator parameters 302 Vehicle parameters 303 HV Battery Parameters 304 Electric drive unit parameters 305 Navigation / Route Parameters 306 Fuel cell characterization 310 Monitoring parameters 312 Power request within permissible range 314 Perform normal operation 315 Perform fuel cell temperature management operations 320 Single fuel cell operation 321 Determine power request 322 Determine the power contribution from high-voltage batteries and fuel cells. 323 Select the first fuel cell operating point and the second fuel cell operating point to achieve the average fuel cell power. 324 Controlling the operation of the fuel cell to alternate between a first fuel cell operating point and a second fuel cell operating point. 325 Power is supplemented from the HV battery to meet the power demand. 330 Dual fuel cell operation 331 Determine power request 332 Determine the power contributions from the high-voltage battery, the first fuel cell, and the second fuel cell. 333 Select the operating point of the first fuel cell and the operating point of the second fuel cell to achieve the average fuel cell power. 334 Controlling the operation of the first and second fuel cells to generate electrical power 335 Power is supplemented from the HV battery to meet the power demand.

[0113] The execution of process 300 may be performed as follows. The steps of process 300 may be performed in a suitable order, and are not limited to those described in the reference. Figure 3 The order described. As used herein, the term “1” indicates an affirmative answer or “yes”, and the term “0” indicates a negative answer or “no”.

[0114] Control routine 300 takes into account multiple parameters, including operator parameters 301; vehicle parameters 302; high-voltage battery parameters 303; electric drive unit parameters 304; navigation / route parameters 305; fuel cell power unit parameters 306, such as reference parameters. Figure 2A The performance characterization 200 of the described (multiple) fuel cell power units 20, 20' is described. Alternatively, one or more of the fuel cell power units 20 may have a reference... Figure 2B The performance characterization described is 260. Alternatively, one or more of the fuel cell power units 20, 20' may have a reference... Figure 2C The performance characterization described is 600.

[0115] Operator parameter 301 is determined based on operator input to various control devices and includes power requests in the form of operator requests for torque or acceleration, or operator braking requests. As a non-limiting example, other secondary operator requests that may affect vehicle power include operator requests for heating, ventilation, and air conditioning; operator requests for lighting, etc., which may be part of auxiliary power unit 60. Operator parameter 301 is used to determine power requests, including, for example, power requests for vehicle acceleration, power requests for vehicle braking, and power requests for mechanical torque.

[0116] Vehicle parameter 302 is determined based on vehicle operation, and by way of non-limiting example, these vehicle parameters include vehicle speed, road load including uphill and downhill sections, vehicle payload, ambient temperature, accessory power, etc.

[0117] As a non-limiting example, the high-voltage battery parameters (HV battery parameters) 303 include the state of charge (SOC), charging / discharging power, temperature, minimum and maximum SOC limits, minimum and maximum charging and discharging limits, etc. of the high-voltage battery 10.

[0118] The electric drive unit parameter 304 includes the continuous and maximum power limits and range of the electric drive unit 50.

[0119] Navigation / Route Parameters 305 include parameters related to traffic and route planning, such as city / highway / urban area, uphill / downhill, etc., as determined for the expected route. Route parameters can be input via propulsion system learning software, driven push-button input, etc.

[0120] The fuel cell power unit parameters (fuel cell characterization) 306 include multiple performance characteristics 200 of the multiple fuel cell power units 20 described with reference to Figure 2, as well as other parameters related to power state, power / time state, minimum and maximum voltage limits, voltage cycling, temperature, etc.

[0121] The control routine 300 monitors and evaluates multiple parameters including: operator parameters 301, vehicle parameters 302, high-voltage battery parameters 303, electric drive unit parameters 304, navigation / route parameters 305, and fuel cell power unit parameters 306 (step 310).

[0122] The evaluation of multiple parameters includes determining whether the power request is within the permissible range for executing control routine 300 (312). The power request is within the permissible range for executing control routine 300 when the power demand for the electrical power output from (multiple) fuel cells 20 is within the range that will enable cryogenic operation of (multiple) fuel cells 20. This determination that the electrical power output from (multiple) fuel cells 20 is within the range that will enable cryogenic operation of (multiple) fuel cells 20 is system-specific and takes into account the maximum torque capability of the electric drive unit 50, the electrical power capacity of the high-voltage battery 10, the electrical power capacity of (multiple) fuel cells 20, and (multiple) nonlinear power-temperature relationships 210 of (multiple) fuel cells 20. This information can be predetermined during development and calibrated and stored in and retrieved from the memory of the controller 70. This information can also be updated throughout its lifespan via equations, downloaded during service via an interface plug, or via conductive devices such as satellites.

[0123] When the power request is outside the permissible range for executing the control program 300 (312) (0), the torque generation system 100 is commanded to operate normally (314).

[0124] When the power request is within the permissible range (312) (1) for executing control routine 300, the operation of torque generation system 100 is commanded to perform fuel cell temperature management to advantageously employ applicable nonlinear power-temperature relationships 210, 260, 600 of the fuel cells 20, 20' to manage the temperature of the fuel cells 20, 20'.

[0125] Control routine 300 uses optimization software to understand and control torque generation system 100 to meet power requests while performing fuel cell temperature management operations. This includes: balancing vehicle parameters 302, high-voltage battery parameters 303, electric drive unit parameters 304, navigation / route parameters 305, and fuel cell power unit parameters 306; and controlling the operation of torque generation system 100 in response to operator parameters 301 for acceleration and / or braking, etc. (step 315).

[0126] For reference Figure 2AThe described fuel cell power unit 20 has a nonlinear power-temperature relationship 210, which has a local temperature maximum 212 occurring at a first power level 213 and a local temperature minimum 216 occurring at a second power level 217. A first operating point 225 is selected that is less than the first power level 213 of the fuel cell power unit 20, and a second operating point 235 is selected that is greater than the first power level 213 and less than a third power level 219. The first operating point 225 and the second operating point 235 are selected to achieve an average power level from the embodiment of the fuel cell power unit 20 having the nonlinear power-temperature relationship 210, and are responsive to power requests when considering the power available from the high-voltage battery 10. The purpose of this operation, which controls the average power level generated by the fuel cell power unit(s) 20 by periodically controlling the first operating point 225 and the second operating point 235, is to achieve a reduction in the operating temperature of the fuel cell power unit(s) 20, thereby providing operating conditions that improve service life compared to operation at higher operating temperatures. The first operating point 225 and the second operating point 235 are selected such that the periodic control of the fuel cell power unit(s) 20 achieves an average power over time in response to a power request. In one embodiment, for the nonlinear power-temperature relationship 210, the first operating point 225 and the second operating point 235 are respectively a low power level and a medium power level, wherein the low power level and the medium power level are defined and described in the context of the maximum power output of the electric drive unit 50. It should be understood that, in alternatives, the foregoing description includes using a reference... Figure 2B The nonlinear power-temperature relationship 260 is described with a first operating point 275 and a second operating point 285. It should be understood that, in alternative embodiments, the foregoing description includes the use of a reference... Figure 2C The nonlinear power-temperature relationship described is at a selected operating point of 600.

[0127] Refer again Figure 3When the torque generation system 100 includes a single fuel cell power unit 20 (step 320), the process includes determining a power request (step 321) and determining the desired electrical power contributions from the high-voltage battery 10 and the fuel cell 20 (step 322), which are delivered to the electric drive unit 50 to achieve traction efficiency. A first operating point 225 and a second operating point 235 of the fuel cell power unit 20 are selected to achieve an average electrical power level from the fuel cell power unit 20 (step 323), which is responsive to the power request, taking into account the electrical power available from the high-voltage battery 10. The operation of the fuel cell power unit 20 is controlled to alternate between the first operating point 225 and the second operating point 235 (step 324), and supplemental electrical power is supplied from the high-voltage battery 10 to meet the power request (step 325).

[0128] The operation of the fuel cell power unit 20 can take the form of generating a positive traction torque in response to an operator's request for acceleration, or generating a negative traction torque in response to an operator's request for braking. The control can also take the form of generating electrical power to charge the high-voltage battery 10.

[0129] Operation of the fuel cell power unit 20 may include periodically alternating the electrical power output from the fuel cell power unit 20 between a first operating point (A) and a second operating point (B) to transfer electrical power to the electric drive unit 50 of the torque generation system 100 to generate mechanical torque in response to a power request. For illustrative purposes, the first operating point (A) corresponds to operating point 225 described with reference to FIG. 2, and the second operating point (B) corresponds to second operating point 235 described with reference to FIG. 2. This operation may include periodically alternating the electrical power output from the fuel cell power unit 20 between the first operating point (A) and the second operating point (B) with a pulse width modulation duty cycle (PWM-DC) having a frequency and duty cycle responsive to a power request. The frequency may be a fixed frequency or alternatively a variable frequency. The fuel cell power unit 20 is periodically controlled at one of the first operating point (A) and the second operating point (B) to achieve an average power over time that achieves an average operating temperature of the fuel cell power unit 20 below a target operating temperature. Reference Figure 4A The square wave 410 schematically illustrates an example of operation that involves periodically alternating the electrical power output from the fuel cell power unit 20 (FCP) between a first operating point (A) and a second operating point (B).

[0130] When the torque generation system 100 includes an array 22 of fuel cell power units 20, the process includes the following (step 330). It should be understood that when the array 22 of fuel cell power units 20 is employed, one or more of the fuel cell power units 20 may have performance characterization 200 (such as, reference to...). Figure 2A (As described), one or more of the fuel cell power units may have performance characteristics 250 (such as, reference 250). Figure 2B The described), and / or one or more of the fuel cell power devices may have performance characterizations 600 (such as, reference ). Figure 2C (Described). A power request is determined (step 331), and the desired electrical power contribution from the array 22 of the high-voltage battery 10 and fuel cell 20 is also determined (step 332), which is delivered to the electric drive unit 50 to achieve traction efficiency. Taking into account the electrical power available from the high-voltage battery 10, a first operating point 225 and a second operating point 235 for each fuel cell power unit in the array 22 of fuel cell power units 20 are selected to achieve an average electrical power level from all fuel cell power units 20 in response to the power request (step 333).

[0131] The operation of the array 22 of the fuel cell power unit 20 is controlled (step 334), and supplemental electrical power is supplied from the high-voltage battery 10 to meet the power request (step 335). This may include, for example, transferring electrical power from the array 22 of the fuel cell power unit 20 and the high-voltage battery 10 to the electric drive unit 50. This may include, for example, transferring electrical power from the array 22 of the fuel cell power unit 20 to the electric drive unit 50 without power from the high-voltage battery 10. This may include, for example, transferring electrical power from the high-voltage battery 10 to the electric drive unit 50 while the array 22 of the fuel cell power unit 20 is deactivated. This may include, for example, transferring electrical power from the electric drive unit 50 and the array 22 of the fuel cell power unit 20 to the high-voltage battery 10. This may include, for example, transferring electrical power from the electric drive unit 50 to the high-voltage battery 10 while the array 22 of the fuel cell power unit 20 is deactivated.

[0132] The operation of the array 22 of the fuel cell power unit 20 is controlled to generate a positive traction torque in response to an operator's request for acceleration, or a negative traction torque in response to an operator's request for braking. This control can take the form of generating electrical power to charge the high-voltage battery 10. During this period, energy from the fuel cell power unit 20 is transferred to the high-voltage battery.

[0133] The operation control routine 300 may include different amplitudes, frequencies, and duty cycles for a first operating point (A) and a second operating point (B) to optimally balance overall optimization. This optimization may or may not follow the instantaneous value of the power request.

[0134] Operation of the fuel cell power unit 20 may include: using PWM commands to periodically alternate the electrical power output from each of the fuel cell power units 20 between a first operating point (A) and a second operating point (B) to deliver electrical power to the electric drive unit 50 of the torque generation system 100 to generate mechanical torque in response to a power request. These PWM commands have a frequency and duty cycle responsive to the power request. For illustrative purposes, the first operating point (A) corresponds to operating point 225 described with reference to FIG. 2, and the second operating point (B) corresponds to the second operating point 235 described with reference to FIG. 2.

[0135] The frequency of the PWM command can be a fixed frequency or, alternatively, a variable frequency. The fuel cell power unit 20 is periodically controlled between a first operating point (A) and a second operating point (B) to achieve an average power over time that results in an average operating temperature of the fuel cell power unit 20 that is below the target operating temperature.

[0136] Refer to each Figure 4B The first PWM command 420 and the second PWM command 425 schematically illustrate an example of operation, which includes periodically alternating the electrical power output from the first fuel cell power unit 20 and the second fuel cell power unit 20 between a first operating point 225 (A) and a second operating point (B). In this example, the first and second fuel cell power units 20 are controlled to periodically alternate between the first operating point (A) and the second operating point (B) to deliver electrical power to the electric drive unit 50 of the torque generation system 100, wherein the first PWM command 420 and the second PWM command 425 operate at the same frequency and the phase difference between the first PWM command 420 and the second PWM command 425 is 180 degrees.

[0137] Refer to each Figure 4C The first PWM command 430 and the second PWM command 435 are illustrated in another example of operation, which includes periodically alternating the electrical power output from the first fuel cell power unit 20 and the second fuel cell power unit 20 between a first operating point 225 (A) and a second operating point (B). In this example, the first and second fuel cell power units 20 are controlled to periodically alternate between the first operating point (A) and the second operating point (B) to deliver electrical power to the electric drive unit 50 of the torque generation system 100, wherein the first PWM command 430 and the second PWM command 435 operate at the same frequency and in phase, respectively.

[0138] Refer to each Figure 4DThe first PWM command 440 and the second PWM command 445 schematically illustrate another example of operation, which involves periodically alternating the electrical power output from the first fuel cell power unit 20 and the second fuel cell power unit 20 between a first operating point (A) and a third operating point (C). In this example, the first and second fuel cell power units 20 are controlled to periodically alternate between the first operating point (A) and the third operating point (C) to deliver electrical power to the electric drive unit 50 of the torque generation system 100, wherein the first PWM command 440 and the second PWM command 445 operate at the same frequency and are 180 degrees out of phase. In this embodiment, the amplitude of the third operating point (C) is greater than the amplitude of the second operating point (B).

[0139] Refer to each Figure 4E The first PWM command 450 and the second PWM command 455 are illustrated in another example of operation, which includes periodically alternating the electrical power output from the first fuel cell power unit 20 and the second fuel cell power unit 20 between a first operating point (A) and a second operating point (B). In this example, the first and second fuel cell power units 20 are controlled to periodically alternate between the first operating point (A) and the second operating point (B) to deliver electrical power to the electric drive unit 50 of the torque generation system 100, wherein the first PWM command 450 operates at a first frequency different from the second frequency of the second PWM command 455.

[0140] Refer to each Figure 4F The first PWM command 460 and the second PWM command 465 graphically illustrate another example of operation, which includes periodically alternating the electrical power output from the first fuel cell power unit 20 and the second fuel cell power unit 20 between a first operating point (A) and a second operating point (B). In this example, the first fuel cell power unit 20 is controlled to periodically alternate between the first operating point (A) and the second operating point (B) to deliver electrical power to the electric drive unit 50 of the torque generation system 100, and the second fuel cell power unit operates continuously at the first operating point (A). In one embodiment, the second fuel cell power unit is deactivated when controlled to the first operating point (A), which allows cooling of the second fuel cell power unit 20 to occur.

[0141] Refer to each Figure 4GThe first command 470 and the second command 475 graphically illustrate another example of operation, which includes periodically alternating the electrical power output from the first fuel cell power unit 20 and the second fuel cell power unit 20 between a first operating point (A) and a second operating point (B). In this example, the first command 470 and the second command 475 respectively provide a ramp transition between the first operating point (A) and the second operating point (B), i.e., the rate of change of time therebetween.

[0142] Figure 5 The operation of an embodiment of the fuel cell power unit 20 is illustrated graphically, with temperature 502 and power 504 plotted with respect to time 510. Other parameters include inlet temperature 511 and total power 514. Operating conditions include continuous operating conditions (515) and periodic operating conditions (516), wherein the periodic operating conditions (516) employ the control concepts described herein. The obtained data include fuel cell temperature (512) under continuous operating conditions and fuel cell temperature (513) under periodic operating conditions. The results show that, for the same average power output, the fuel cell temperature (513) under periodic operating conditions is lower than that under continuous operating conditions (512).

[0143] The concepts described herein provide embodiments of an operating torque generation system 100 to meet performance requirements while actively controlling the temperature of (multiple) fuel cells 20, and associated control strategies that improve their service life. This includes power cycle management based on the power / temperature relationship of (multiple) characteristic features of the (multiple) fuel cells 20.

[0144] Exemplary embodiments may be described herein in terms of functional and / or logical block compositions and various processing steps. It should be understood that such block compositions may be implemented by any number, combination, or set of mechanical and electronic hardware, software, and / or firmware components configured to perform specified functions. For example, embodiments may employ various combinations of mechanical and electronic components, integrated circuit components, memory elements, digital signal processing elements, logic elements, lookup tables, etc., all of which may implement various functions under the control of one or more microprocessors or other control devices. Furthermore, those skilled in the art will understand that exemplary embodiments may be practiced in conjunction with mechanical and / or electronic systems, and the vehicle system described herein is merely an exemplary embodiment of possible implementations. It should be noted that many alternative or additional functional relationships or physical connections may exist in one or more embodiments.

[0145] Flowcharts and block diagrams within flowcharts illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, including one or more executable instructions for implementing one or more specified logical functions. It will also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a system based on special-function hardware or a combination of special-function hardware and computer instructions that performs the specified functions or actions. These computer program instructions may also be stored in a computer-readable medium that can instruct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of art comprising a set of instructions that implements the functions / actions specified in the flowcharts and / or one or more block diagram blocks.

[0146] The detailed description and accompanying drawings support and describe this teaching, but the scope of this teaching is defined solely by the claims. While some of the best modes and other embodiments for carrying out this teaching have been described in detail, various alternative designs and embodiments exist for practicing the teaching as defined in the appended claims.

Claims

1. A torque generating system, comprising: Fuel cell power unit, high-voltage battery, electric drive unit and controller; The fuel cell power unit and the high-voltage battery are electrically connected to a high-voltage bus, and the electrical power is supplied to the electric drive unit via the high-voltage bus. The fuel cell power device has a nonlinear power-temperature relationship, which has a local temperature maximum value at a first power level and a local temperature minimum value at a second power level. Wherein, the first operating point of the fuel cell power device is less than the first electrical power level; Wherein, the second operating point of the fuel cell power device is greater than the first power level and less than the third power level, wherein the third power level causes the operation of the fuel cell power device to produce a fuel cell temperature less than the maximum local temperature. The fuel cell power unit is controlled to either the first operating point or the second operating point to deliver electrical power to the electric drive unit; and The high-voltage battery and the fuel cell power unit cooperate to transfer electrical power to the electric drive unit, thereby generating mechanical torque in response to power requests.

2. The system of claim 1, wherein, The second operating point of the fuel cell power unit corresponds to the second electrical power level associated with the local minimum temperature.

3. The system according to claim 1, wherein, The electric drive unit includes a motor coupled to the vehicle's drivetrain; and wherein the high-voltage battery and the fuel cell power unit cooperate to deliver electrical power to the motor, thereby generating traction torque in response to the power request.

4. The system according to claim 3, wherein, The high-voltage battery and the fuel cell power unit cooperate to deliver electrical power to the motor, thereby generating positive traction torque in response to the power request, wherein the power request includes a request for vehicle acceleration.

5. The system according to claim 3, wherein, The high-voltage battery and the fuel cell power unit cooperate to respond to torque, thereby generating electrical power through the motor to produce negative traction torque in response to the power request, wherein the power request includes a request for braking.

6. The system according to claim 1, wherein, The electric drive unit includes a motor coupled to a stationary electric motor; and wherein the high-voltage battery and the fuel cell power unit cooperate to transfer electrical power to the motor, thereby generating mechanical torque in response to the power request.

7. The system according to claim 1, wherein, Controlling the fuel cell power unit to one of the first operating point or the second operating point to deliver electrical power to the electric drive unit includes: the fuel cell power unit being controlled to periodically alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system, thereby generating mechanical torque in response to the power request.

8. The system according to claim 7, wherein, The fuel cell power device is controlled to periodically alternate between the first operating point and the second operating point, comprising: the fuel cell power device is controlled to alternate between the first operating point and the second operating point at a frequency and duty cycle in response to the power request.

9. The system according to claim 7, wherein, The fuel cell power unit is periodically controlled between the first operating point and the second operating point to achieve an average power over time, wherein the average power achieves an average operating temperature of the fuel cell power unit that is lower than the target operating temperature.

10. The system of claim 1, further comprising the fuel cell power unit being controlled to deliver electrical power to charge the high-voltage battery.

11. A torque generating system, comprising: The system comprises a first fuel cell power unit, a second fuel cell power unit, a high-voltage battery, an electric drive unit, and a controller. The first fuel cell power unit, the second fuel cell power unit, and the high-voltage battery are electrically connected to a high-voltage bus, and the electrical power is supplied to the electric drive unit via the high-voltage bus. Each of the first fuel cell power device and the second fuel cell power device has a nonlinear power-temperature relationship, which has a local temperature maximum value at a first power level and a local temperature minimum value at a second power level. Wherein, the first operating point of each of the first fuel cell power device and the second fuel cell power device is less than the first power level, and wherein, the second operating point of each of the fuel cell power devices is greater than the first power level and occurs at a third power level, wherein, the third power level causes the operation of the fuel cell power device to produce a fuel cell temperature less than the maximum local temperature. The first fuel cell power unit is controlled to one of the first operating point or the second operating point to deliver electrical power to the electric drive unit. The second fuel cell power unit is controlled to either the first or the second operating point to deliver electrical power to the electric drive unit; and The high-voltage battery, along with the first and second fuel cell power units, cooperate to deliver electrical power to the electric drive unit, thereby generating mechanical torque in response to a power request.

12. The system of claim 11, comprising: The first fuel cell power unit is controlled to the second operating point, while the second fuel cell power unit is controlled to the first operating point, so as to transfer electrical power to the electric drive unit.

13. The system of claim 11, comprising: The first fuel cell power unit is controlled to one of the first operating point or the second operating point, and the second fuel cell power unit is deactivated.

14. The system according to claim 11, wherein, Controlling the first fuel cell power unit and the second fuel cell power unit to one of the first operating point or the second operating point to deliver electrical power to the electric drive unit includes: the first fuel cell power unit and the second fuel cell power unit being controlled to periodically alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system, thereby generating mechanical torque in response to the power request.

15. The system according to claim 14, wherein, The first fuel cell power unit and the second fuel cell power unit are controlled to periodically alternate between the first operating point and the second operating point, comprising: the first fuel cell power unit is controlled to alternate between the first operating point and the second operating point at a first frequency and a first duty cycle, and the second fuel cell power unit is controlled to alternate between the first operating point and the second operating point at a second frequency and a second duty cycle.

16. The system according to claim 15, wherein, The first frequency is equal to the second frequency; and the phase difference between the first frequency and the second frequency is 180 degrees.

17. The system according to claim 15, wherein, The first frequency is equal to the second frequency; and wherein the first frequency and the second frequency are in phase.

18. The system according to claim 15, wherein, The first frequency is different from the second frequency.

19. A method for controlling a fuel cell power device, wherein, The fuel cell power unit is electrically connected to a torque generation system, and the method includes: Determining the nonlinear power-temperature relationship of the fuel cell power device includes determining the maximum local temperature at a first power level and the minimum local temperature at a second power level. Determine a first operating point for the fuel cell power device that is less than the first electrical power level; The fuel cell power device is determined to be at a second operating point that is greater than the first power level and occurs at a third power level, wherein the third power level produces a fuel cell temperature that is less than the maximum local temperature. The fuel cell power unit is controlled to alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system, thereby generating mechanical torque.

20. The method of claim 19, further comprising: Determine the power request for the torque generation system; Determine the magnitude of the battery power transmitted between the torque generation system and the high-voltage battery; The fuel cell power unit is controlled to periodically alternate between the first operating point and the second operating point to deliver electrical power to the electric drive unit of the torque generation system. as well as The magnitude of the battery power transmitted between the torque generation system and the high-voltage battery is controlled based on the average electrical power of the electric drive unit in response to the power request and transmitted by the fuel cell power unit to the torque generation system.

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