WO2024042482A1

WO2024042482A1 - System and method for operating a hybrid electric powertrain in a vehicle

Info

Publication number: WO2024042482A1
Application number: PCT/IB2023/058408
Authority: WO
Inventors: Ankit Vinodchandra PATEL; Apoorv Prakash Hiremath
Original assignee: Cummins Power Generation Limited
Priority date: 2022-08-24
Filing date: 2023-08-24
Publication date: 2024-02-29

Abstract

One embodiment of the present disclosure is a hybrid electric powertrain. The hybrid electric powertrain includes: one or more fuel cells configured to produce a DC power output, one or more batteries configured to produce a DC power output, one or more inverters coupled to the one or more fuel cells and the one or more batteries, the one or more inverters configured to convert the DC power output of the one or more fuel cells and the one or more batteries to produce one or more AC power outputs, and an AC power bus coupled to the one or more inverters and configured to combine the AC power outputs and provide a combined AC power output to a motor.

Description

SYSTEM AND METHOD FOR OPERATING A HYBRID ELECTRIC POWERTRAIN IN A VEHICLE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Patent Application No. 63/400633, filed on August 24, 2022, the entirety of which is incorporated by reference herein.

TECHNICAL FIELD

[0002] The present disclosure relates to powertrains for vehicles. More specifically, according to some embodiments, the present disclosure relates to systems and methods for supplying required voltage and power to an AC traction motor when a hybrid architecture including batteries and fuel cells is implemented.

BACKGROUND

[0003] Some conventional vehicle powertrains are powered by gaseous fuels, such as diesel fuel. Recently, manufacturers have increasingly been looking to electrical technologies as a way to power vehicles, instead of or in addition to gaseous fuels such as diesel (e.g., using fully electric or hybrid electric powertrains). While vehicles powered by electricity have many benefits including potential economic and environmental benefits, the electric powered vehicles are not without their challenges. More specifically, electrically powered vehicles may utilize specialized equipment that can increase the cost and/or complexity of the vehicle.

[0004] Increasingly, manufacturers are incorporating electric powertrains into their vehicles (e.g., fully electric or hybrid electric). While electric powered powertrains include many benefits, some of the equipment required for electric powertrains can be expensive and/or difficult to find. More specifically, hybrid electric powertrains that utilize batteries and fuels cells as the fuel sources can require expensive and difficult to find high voltage direct current (DC)/DC converters. The systems and methods disclosed herein illustrate hybrid electric powertrain electrical circuit architectures that may not require such high voltage DC/DC converters within a hybrid electric powertrain.

SUMMARY [0005] One embodiment of the present disclosure is a hybrid electric powertrain. The powertrain includes: one or more fuel cells configured to produce a first DC power output, one or more batteries configured to produce a second DC power output, one or more inverters coupled to the one or more fuel cells and the one or more batteries, the one or more inverters configured to convert the first DC power output and the second DC power output to produce one or more AC power outputs, and an AC power bus coupled to the one or more inverters and configured to receive the one or more AC power outputs and provide a AC power output to a motor.

[0006] In some embodiments, each of the one or more inverters comprises one or more isolated transformers configured to step-up the AC voltage produced by the one or more inverters. In some embodiments, the hybrid electric powertrain further includes a motor control unit. The motor control unit comprises one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive a voltage measurement from the one or more inverters, determine one or more control inputs for the motor using a motor control algorithm, the one or more control inputs determined based on the voltage measurement and one or more operative conditions of the vehicle, and control operation of the motor to implement the one or more control inputs. In some embodiments, the one or more control inputs includes at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus. In some embodiments, the one or more processors are configured to determine the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle and control operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus. In some embodiments, the motor control unit is integrated into a controller for the one or more inverters.

[0007] In some embodiments, the one or more operative conditions of the vehicle includes at least one of a speed of the vehicle, a terrain the vehicle is traversing, and an operating mode of the vehicle. In some embodiments, the motor control algorithm includes at least one of vector control, direct torque control, pulse width modulation control, and space vector pulse width modulation control. In some embodiments, the hybrid electric powertrain is implemented without the use of DC/DC converters.

[0008] Another embodiment of the present disclosure is a hybrid electric powertrain. The powertrain of a vehicle includes: a fuel cell configured to produce a first DC voltage, a battery configured to produce a second DC voltage, an inverter coupled to the fuel cell and the battery, the o inverter configured to convert the first DC voltage and the second DC voltage to an AC voltage, an AC power bus coupled to the one or more inverters and configured to provide the AC voltage to a motor, a transformer coupled to the AC power bus configured to convert a voltage output of the AC power bus, and a cycloconverter coupled to the transformer configured to convert a frequency of the voltage output of the AC power bus.

[0009] In some embodiments, the transformer is configured to generate a fixed AC voltage at a constant frequency, and the cycloconverter converts the fixed AC voltage at the constant frequency and outputs a variable AC voltage at a variable frequency. In some embodiments, the motor control unit is integrated into a controller for the inverter. In some embodiments, the controller for the inverter is communicably coupled with a vehicle control unit and is configured to: determine a desired speed of the motor, and implement the desired speed of the motor via a frequency change to update a speed and a torque of the motor. In some embodiments, the one or more inverters are coupled to the AC power bus in parallel. In some embodiments, the motor control unit is communicably coupled to the cycloconverter and is configured to drive one or more control outputs to the cycloconverter to adjust the speed and torque of the motor.

[0010] In some embodiments, the cycloconverter includes one or more processing circuits including one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive a voltage measurement from the inverter, determine one or more control inputs for the motor using a motor control algorithm , the one or more control inputs determined based on: the voltage measurement and one or more operative conditions of the vehicle, and control operation of the motor to implement the one or more control inputs.

[0011] In some embodiments, the motor is a variable speed traction motor which receives the voltage output of the AC power bus including the converted frequency of the voltage output by the cycloconverter. In some embodiments, the transformer is configured to step up the voltage output of the AC power bus from a lower voltage to a higher voltage, wherein the lower voltage is between 270 volts AC to 800 volts AC and the higher voltage is at least 1300 volts AC. In some embodiments, the battery produces an output between 270 volts DC to 600 volts DC, wherein the fuel cell generates an output voltage between 600 volts DC to 800 volts DC.

[0012] Another embodiment of the present disclosure is a method for operating a hybrid electric powertrain in a vehicle. The method includes producing a first DC power output from one or more fuel cells, producing a second DC power output from one or more batteries, converting the first DC power output and the second DC power output to produce one or more AC power outputs, and combining the one or more AC power outputs to provide a combined AC power output to a motor. In some embodiments, the method further includes receiving a voltage measurement from one or more inverters, determining one or more control inputs for the motor using a motor control algorithm and based on the voltage measurement and one or more operative conditions of the vehicle, and controlling operation of the motor to implement the one or more control inputs.

[0013] In some embodiments, the one or more control inputs include at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus. In such an embodiment, the method further includes determining the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle and controlling operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus.

[0014] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.

BRIEF DESCRIPTION OF THE FIGURES

[0015] FIG. l is a schematic representation of a vehicle with a hybrid electric powertrain. [0016] FIG. 2 is a schematic representation of a hybrid electric powertrain of the vehicle of FIG. 1, according to an illustrative embodiment.

[0017] FIG. 3 is a schematic representation of another hybrid electric powertrain of the vehicle of FIG. 1, according to an illustrative embodiment.

[0018] FIG. 4 is a schematic representation of another hybrid electric powertrain of the vehicle of FIG. 1, according to an illustrative embodiment.

DETAILED DESCRIPTION

[0019] Following below are more detailed descriptions of various concepts related to, and implementations of systems and methods of a hybrid electric powertrain without the use of expensive and hard to find equipment. Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0020] According to various example embodiments, the systems and methods disclosed herein describe hybrid electric powertrains which utilize a combination of one or more batteries and one or more fuel cells to power a vehicle (e.g., locomotives, cars, etc.).

[0021] Referring now to FIG. 1, a vehicle with a hybrid electric power train 100 is shown, according to an example embodiment. The vehicle 100 includes a hybrid fuel system 102, a variable speed motor 104, a transmission 106, and a differential drive system. The hybrid fuel system 102 operably coupled to the variable speed motor 104 and provides power to the vehicle 100 to propel the vehicle 100. The hybrid fuel system can include batteries and/or fuel cells configured to provide electric power to the vehicle 100. The hybrid fuel system is explained in more detail below with respect to FIG. 2, 3, and 4 below. The variable speed motor 104 receives power from the hybrid fuel system 102 that provides an input energy to output usable work or energy to in some instances propel the vehicle 100. As a result of the power output from the variable speed motor 104, the transmission 106 may manipulate the speed of the rotating input shaft (e.g., the crankshaft) to affect a desired drive shaft 108 speed. The rotating drive shaft 108 is received by a differential 110, which provides the rotation energy of the drive shaft 108 to the final drive 112. The final drive 112 then propels or moves the vehicle 100.

[0022] Referring now to FIG. 2, a schematic hybrid electric powertrain 200. While the presently illustrated powertrain does not include a fossil fuel-driven prime mover, it should be understood that, in some embodiments, elements of the present disclosure can be utilized in systems including fossil fuel-driven prime movers such as diesel engines.

[0023] The fuel cell system 202 includes one or more fuel cells 206, an air system 208, a hydrogen (Hz) storage 210, a fuel cell cooling system 212, and an exhaust system 214. The fuel cells 206 are configured to use the chemical energy of a fuel and an oxidizing agent to create electrical energy. In the exemplary embodiment shown in FIG. 2, the fuel source is hydrogen which is stored in the hydrogen storage 210 and the oxidizing agent is oxygen which is provided by the air system 208. In this embodiment, the fuel cells 206 receive hydrogen and oxygen from the hydrogen distributer 216 and oxygen distributer 218 respectively. The fuel cells 206 are configured to combine the hydrogen and oxygen to produce electricity (e.g., a first DC power output).

[0024] In some embodiments, the fuel cell system 202 can also include the fuel cell cooling system 212. The cooling system 212 is configured to regulate the temperature of the fuel cells 206 to ensure proper operation of the fuel cells 206. The fuel cell system 202 can also include an exhaust system 214. The exhaust system 214 is configured to receive and collect the byproducts produced by the fuel cells 206. The byproducts can include unused hydrogen and water produced as a byproduct of producing electricity in the fuel cells 206. The exhaust system 214 also expels the byproducts collected from the hybrid electric powertrain 200 outside the hybrid electric powertrain 200.

[0025] The battery system 204 includes one or more batteries 220. In some embodiments, the battery system 204 also includes a battery management system (BMS) controller 222 and/or a battery cooling system 224. The batteries 220 are also configured to convert chemical energy into electrical energy to produce a second DC power output. The BMS controller 222 can be configured to control the operation of the batteries 220 based on inputs received from the system control module 226. The BMS controller 222 can be coupled to the system control module 226. The system control module 226 is coupled to a vehicle control unit 227 configured to control the vehicle associated with the hybrid electric powertrain 200. In some embodiments, each of the batteries 220 generates an output voltage of 800 volts. The cooling system 224 is configured to regulate the temperature of the batteries 220.

[0026] In some embodiments, each of the batteries 220 and fuel cells 206 may be coupled to DC/DC converters 228. The DC/DC converters can convert the voltage received from the fuel cells 206 (e.g., 600 volts) and the batteries 220 (e.g., 800 volts) from their respective voltages to a specific predetermined voltage. For example, the DC/DC converters convert the voltage from 600 volts/800 volts to 1800 volts, in some embodiments. Each of the DC/DC converters is connected to a DC power bus 230. In some embodiments, DCAC inverter 232 is coupled to the DC power bus 230 and is configured to convert the DC voltage/current received from the DC power bus into an AC voltage/current that may be supplied to an AC auxiliary load 234. The AC auxiliary load 234 represents one or more pieces of auxiliary equipment configured to receive AC power. In some embodiments, DC/DC converter 236 is coupled to the DC power bus 230 and is configured to convert the DC voltage and/or current received from the DC power bus 230 to a DC voltage/current that may be supplied to the DC auxiliary load 238. The DC auxiliary load 238 represents one or more pieces of auxiliary equipment configured to receive DC power.

[0027] In some embodiments, a DC/ AC traction inverter 240 is coupled to the DC power bus 230. The DC/ AC traction inverter 240 is configured to receive the first DC power output and the second DC power output DC voltage from the DC power bus 230 and convert the DC power output to an AC power output that can be used by the motor 242. In some embodiments, traction inverter 240 also perform functions such as voltage boosting, switch protection and regenerative braking within the powertrain 100. In some embodiments, the motor 242 can be an AC traction motor, therefore, the DC power from the DC power bus can be converted to AC power to be used by the motor 242. For example, in an example embodiment, the DC/AC traction inverter 240 converts 1800 volts DC to a lower voltage (e.g., 1000 volts AC to 1300 volts AC) required for the motor 242. In some embodiments, the DC/AC inverter 240 is coupled to a power electronics cooling system 243 configured to regulate the temperature of the DC/AC inverter 240. The mechanical power produced by the motor 240 is provided to the transmission (not shown) which ultimately propels the vehicle associated with the powertrain forward. As a result of the power output from the motor 242, the transmission (not shown) can manipulate the speed of the rotating crankshaft (not shown) to affect a desired drive shaft speed. The rotating drive shaft can be received by a differential that provides the rotation energy of the drive shaft to the final drive wheels 246 to propel or move the vehicle associated with the powertrain 200. While the aforementioned are examples of mechanical components that can be used at the output of the hybrid electric powertrain to move the vehicle, it should be understood that, in various embodiments, various other types of components can be provided at the output of the hybrid electric powertrain to move the vehicle in various example implementations.

[0028] The motor 242 can be coupled to a motor control unit 244 configured to control the operation of the motor 242. In some embodiments, the motor 242 may be a variable speed motor and the motor control unit 244 can control the speed of the motor 242. The motor control unit 244 can include processing circuitry, such as a processor and memory. The processor can be implemented as a general purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. The memory (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or non-volatile memory. The memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0029] The memory (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or nonvolatile memory. Memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0030] FIGS. 3 and 4 below illustrate two exemplary embodiments of hybrid electric powertrains without the use of DC/DC converters. While the illustrated embodiments do not use DC/DC converters, it should be understood that, in some embodiments, DC/DC converters can be used for some components (e.g., such that less DC/DC converters are used, but the designs do not fully eliminate the use of DC/DC converters). [0031] Referring now to FIG. 3, a schematic representation of hybrid electric powertrain 300 of a vehicle is shown, according to an illustrative embodiment. The hybrid electric powertrain 300 includes one or more fuel cell stacks 302 which each include one or more fuel cells configured to produce a first DC power output. The hybrid electric powertrain also includes one or more batteries 304 configured to produce a second DC power output. The hybrid electric powertrain 300 also includes one or more inverters 306, an AC power bus 308, a motor 310, a motor control unit 312, and a transmission 314. The fuel cell stacks 302 can include one or more fuel cells and can be similar to fuel cell system 202 described in more detail above. Each of the fuel cells within the fuels cells stacks 302 is configured to convert chemical energy into electrical energy to produce the first DC power output. The batteries 304 are also configured to convert chemical energy into electrical energy to produce the second DC power output. In some embodiments, the fuel cell stacks 302 can each generate an output voltage ranging from 270-600 volts DC. In some embodiments, the batteries can generate an output voltage ranging from 600-800 volts DC.

[0032] The fuel cell stacks 302 and the batteries 304 can each be coupled to the one or more inverters 306. The one or more inverters 306 can be configured to convert the first DC power output and the second DC power output to produce one or more AC power outputs (e.g., AC voltage). In some embodiments, the one or more inverters 306 can each include isolated transformers 307 within the one or more inverters. The isolated transformer 307 can be configured to step-up or step-down the voltage received and converted/produced by the one or more inverters 306. The isolated transformers are configured to step-up or step down the voltage to provide the voltage required by the motor 310. For example, the isolated transformer 307 can step up the voltage received from the fuel cell stacks 302 (e.g., 270-600 volts) and or the batteries 304 (600-800 volts) to 1300 volts AC. The AC power bus 308 is coupled to the one or more inverters 306 and is configured to receive the one or more AC power outputs from the one or more inverters 306. The AC power bus 308 is configured to provide an AC power output to the motor 310. The one or more inverters 306 can be coupled in parallel to the AC power bus 308 to increase the power capacity of the hybrid electric powertrain 300.

[0033] The motor 310 is coupled to the AC power bus 308 and is configured to receive the voltage from the AC power bus 308. The motor 310 may be a variable speed traction motor. The speed and frequency within the motor 310 can be varied based on the operation of the vehicle. The motor 310 can be coupled to the motor control unit 312 configured to control the operation of the motor 310. In some embodiments, the motor control unit 312 may determine one or more control inputs for the motor 310 using a motor control algorithm. In some embodiments, the one or more control inputs are determined based on the voltage measurement and one or more operative conditions of the vehicle. In some embodiments, the motor control unit 312 can be added as a separate controller which controls the speed and the frequency of the motor. In other embodiments, the motor control unit 312 may be integrated as a part of a controller for the inverter 306. The inverter controller may be communicably coupled with a vehicle control unit to determine the desired speed of the motor for the vehicle and implement a desired speed via frequency change which directly links to speed and torque control of the motor 310. In some embodiments, the motor control unit 312 may include a V/Hz drive control to match the required torque. The motor control unit 312 controller may include different types of motor control algorithms to control the speed/frequency of the motor. These motor control algorithms may include but not limited to vector control, direct torque control, pulse width modulation control, and space vector pulse width modulation. In some embodiments, one or more micro controllers may govern the overall operation of the inverter 306 to control the operation of the motor 310.

[0034] In some embodiments, the motor control unit 312 can control the speed/frequency and voltage of the motor 310 and the one or more inverters 306/AC power bus 308. More specifically, the control inputs may include a speed/frequency of the motor 310, a voltage of the motor 310, a frequency of the one or more inverters 306/AC power bus 308, and a voltage of the one or more inverters 306/AC power bus 308. The motor control unit 312 can implement the control inputs within the motor by adjusting the speed and/or the frequency of the motor 310 and the voltage required by the motor 310. The motor control algorithm can utilize operative conditions of the vehicle as inputs to the algorithm. The operative conditions of the vehicle can include the speed of the vehicle, the terrain the vehicle is traversing, the operating mode of the vehicle (eco mode, regular mode, sport mode, etc.), or any other conditions affecting the vehicle.

[0035] The motor control unit 312 can include processing circuitry, such as a processor and memory. The processor can be implemented as a general purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. The memory (e.g., memory, memory unit, storage device, etc.) can include one or more memory devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or nonvolatile memory. The memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0036] The memory (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or nonvolatile memory. Memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0037] The motor 310 works with the transmission 314 to propel the vehicle forward. More specifically, a result of the power output from the motor 310, the transmission 314 can manipulate the speed of the crankshaft (not shown) to affect a desired drive shaft speed. The rotating drive shaft (not shown) is received by a differential (not shown), which provides the rotation energy of the drive shaft to the final drive wheels (not shown) to propel or move the vehicle associated with the powertrain 300.

[0038] The hybrid electric powertrain 300 as shown can be implemented without the use of the DC/DC converters 228 and/or the DC/ AC traction inverter 240 included in the hybrid electric powertrain 200 as shown in FIG. 2, in some embodiments. The hybrid electric powertrain 300 can provide benefits such as reduced costs associated with the DC/DC converters 228 and/or the DC/AC traction inverter 240, simplifying the architecture of the hybrid electric powertrain making the hybrid electric powertrain 300 easier to produce and maintain, etc. compared to the hybrid electric powertrain 200. More specifically, in some circumstances, the cost of the inverter 306 can be lower than those of the DC/DC converters 228 and/or the DC/AC inverter traction 240. Additionally, the one or more inverters 306 have a higher technology readiness level (e.g., what stage the of development the technology ranging from technology that is still in the early stages of being developed to technology that is well developed and being implemented) than the DC/DC converters 228 leading to the one or more inverters 306 more readily available and easier to find and include in the hybrid electric powertrain 300.

[0039] Referring now to FIG. 4, a schematic representation of hybrid electric powertrain 400 of a vehicle is shown, according to an illustrative embodiment. The hybrid electric powertrain 400 includes one or more fuel cell stacks 302 which each include one or more fuel cells configured to produce a first DC power output. The hybrid electric powertrain also includes one or more batteries 304 configured to produce a second DC power output. The hybrid electric powertrain 400 also includes one or more inverters 406, an AC power bus 308, a transformer 410, a cycloconverter 412, a motor 310, a motor control unit 312, and a transmission 314. The fuel cell stacks 302 can include one or more fuel cells and can be similar to fuel cell system 202 described in more detail above. Each of the fuel cells within the fuels cells stacks 302 is configured to convert chemical energy into electrical energy to produce a first DC power output. The batteries 304 are also configured to convert chemical energy into electrical energy to produce a second DC power output. In some embodiments, the fuel cell stacks 302 can generate an output voltage ranging from 270-600 volts DC. In some embodiments, the batteries generate an output voltage ranging from 600-800 volts DC.

[0040] The fuel cell stacks 302 and the batteries 304 can each be coupled to one or more inverters 406. The one or more inverters 406 can convert the first DC power output and the second DC power output received from the fuel cell stacks 302 and the batteries 304 into an AC power voltage. The AC power bus 308 is coupled to the one or more inverters 406 and is configured to receive the one or more AC power outputs from the one or more inverters 406. The AC power bus 308 is configured to provide an AC power output to the motor 310. Specifically, the AC power bus 308 may be configured to combine the one or more AC power outputs to provide a combined AC power output to the motor 310. The one or more inverters 406 can be coupled in parallel to the AC power bus 308 to increase the power capacity of the hybrid electric powertrain 400. In some embodiments, the voltage as measured in the AC power bus 308 can be a low voltage (e.g., 270-800 volts). Therefore, the voltage of the AC power bus 308 may need to be step-upped by the transformer 410. The AC power bus 308 is coupled to the transformer 410 which is configured to convert a voltage output of the AC power bus 308. Specifically, the transformer 410 is configured to step-up or step-down the voltage from the AC power bus 308 to provide the voltage required by the motor 310. For example, the transformer 410 can step up the voltage in the AC power bus from a low voltage (e.g., 270-800 volts) to a higher voltage (e.g., 1300 volts AC).

[0041] The transformer 410 can be coupled to the cycloconverter 412. The cycloconverter 412 can convert the frequency of the AC voltage output of the AC power bus 308 and step- upped by the transformer 410 to a frequency required by the motor. More specifically, the cycloconverter 412 can convert the AC voltage at one frequency into a different AC voltage with a lower but adjustable frequency without an intermediary DC stage. For example, the transformer 410 may be configured to generate a fixed AC voltage at a constant frequency. The cycloconverter 412 may then convert the fixed AC voltage at the constant frequency from the transformer 410 and outputs a variable AC voltage at a variable frequency. The cycloconverter 412 can convert a fixed AC voltage at a constant frequency to output a variable AC voltage at a variable frequency. The motor 310 can be a variable speed motor which requires the converted frequency of the voltage output of the AC power bus (e.g., the variable AC voltage output) by the cycloconverter 412.

[0042] In some embodiments, the cycloconverter 412 can include processing circuitry, such as a processor and memory. The processor can be implemented as a general purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. The memory (e.g., memory, memory unit, storage device, etc.) can include one or more memory devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or non-volatile memory. The memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0043] The memory (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or nonvolatile memory. Memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0044] The motor 310 is coupled to the cycloconverter 412 and is configured to receive the voltage from the cycloconverter 412. The motor 310 can be a variable speed traction motor which requires the variable AC voltage and frequency output by the cycloconverter 412. The speed and frequency within the motor 310 can be varied based on the operation of the vehicle. The motor 310 can be coupled to the motor control unit 312 configured to control operation of the motor 310. In some embodiments, the motor control unit 312 can control the speed and frequency of the motor 310 and the voltage required by the motor 310 to meet the torque and speed requirements for the vehicle. In some embodiments, the motor control unit 312 can utilize a motor control algorithm which will adjust the required voltage and frequency required for the motor 310. Specifically, the motor control unit 312 may be configured to receive a voltage measurement from the one or more inverters 306, determine one or more control inputs for the motor 310 using a motor control algorithm, the one or more control inputs determined based on the voltage measurement and one or more operative conditions of the vehicle, and control operation of the motor 310 to implement the one or more control inputs. In some embodiments, the one or more control inputs include at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus. In some embodiments, the motor control unit 312 may be configured to determine the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle. The motor control unit 312 may be further configured to control operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus. In some embodiments, the motor control unit 312 can be added as a separate controller which controls the speed and the frequency of the motor 310. In other embodiments, the motor control unit 312 may be integrated as a part of a controller for the inverter 406. The inverter controller may be communicably coupled with a vehicle control unit to determine the desired speed of the motor for the vehicle and implement a desired speed via frequency change which directly links to speed and torque control of the motor 310. Specifically, the inverter controller may implement the desired speed of the motor via a frequency change to update a speed and torque of the motor 310. In some embodiments, the motor control unit 312 may include a V/Hz drive control to match the required torque. The motor control unit 312 controller may include different types of motor control algorithms to control the speed/frequency of the motor. These control algorithms may include but not limited to vector control, direct torque control, pulse width modulation control, and space vector pulse width modulation. In some embodiments, one or more micro controllers may govern the overall operation of the inverter 306 to control the operation of the motor 310.

[0045] In some embodiments, the motor control unit 312 can control the speed/frequency and voltage of the motor 310 and the one or more inverters 406/AC power bus 308. More specifically, the control inputs may include a speed/frequency of the motor 310, a voltage of the motor 310, a frequency of the one or more inverters 406/AC power bus 308, and a voltage of the one or more inverters 406/AC power bus 308. The motor control unit 312 can implement and drive the control inputs to cycloconverter 412 to adjust the speed and torque of the motor. The motor control algorithm can utilize operative conditions of the vehicle as inputs to the algorithm. The operative conditions of the vehicle can include the speed of the vehicle, the terrain the vehicle is traversing, the operating mode of the vehicle (eco mode, regular mode, sport mode, etc.), or any other conditions affecting the vehicle. In some embodiments, the motor control algorithm may be implemented by the cycloconverter 412.

[0046] The motor control unit 312 can include processing circuitry, such as a processor and memory. The processor can be implemented as a general purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. The memory (e.g., memory, memory unit, storage device, etc.) can include one or more memory devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or nonvolatile memory. The memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0047] The memory (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. The memory can be or include volatile memory or non- volatile memory. Memory can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application.

[0048] The motor 310 works with the transmission 314 to propel the vehicle forward. More specifically, a result of the power output from the motor 310, the transmission 314 can manipulate the speed of the crankshaft (not shown) to affect a desired drive shaft speed. The rotating drive shaft (not shown) is received by a differential (not shown), which provides the rotation energy of the drive shaft to the final drive wheels (not shown) to propel or move the vehicle associated with the powertrain 400.

[0049] The hybrid electric powertrain 400 as shown can be implemented without the use of the DC/DC converters 228 and/or the DC/ AC traction inverter 240 included in the hybrid electric powertrain 200 as shown in FIG. 2, in some embodiments. The hybrid electric powertrain 400 can provide such as reduced costs associated with the DC/DC converters 228 and/or the DC/ AC traction inverter 240, and also simplifying the architecture of the hybrid electric powertrain making the hybrid electric powertrain 400 easier to produce and maintain compared to the hybrid electric powertrain 200. More specifically, the cost of the inverter 406 is lower than those of the DC/DC converters 228 and/or the DC/ AC traction inverter 240. Additionally, the one or more inverters 406 have a higher technology readiness level (e.g., what stage the of development the technology ranging from technology that is still in the early stages of being developed to technology that is well developed and being implemented) than the DC/DC converters 228 leading to the one or more inverters 406 more readily available and easier to find and include in the hybrid electric powertrain 400.

[0050] As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims. [0051] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0052] The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using one or more separate intervening members, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic. For example, circuit A communicably “coupled” to circuit B may signify that the circuit A communicates directly with circuit B (i.e., no intermediary) or communicates indirectly with circuit B (e.g., through one or more intermediaries).

[0053] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0054] As mentioned above and in one configuration, the “circuits” may be implemented in machine-readable medium for execution by various types of processors, such as the processors. An identified circuit of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified circuit need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the circuit and achieve the stated purpose for the circuit. Indeed, a circuit of computer readable program code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within circuits, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

[0055] While the term “processor” is briefly defined above, the term “processor” and “processing circuit” are meant to be broadly interpreted. In this regard and as mentioned above, the “processor” may be implemented as one or more general-purpose processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), or other suitable electronic data processing components structured to execute instructions provided by memory. The one or more processors may take the form of a single core processor, multi-core processor (e.g., a dual core processor, triple core processor, quad core processor, etc.), microprocessor, etc. In some embodiments, the one or more processors may be external to the apparatus, for example the one or more processors may be a remote processor (e.g., a cloud based processor). Alternatively or additionally, the one or more processors may be internal and/or local to the apparatus. In this regard, a given circuit or components thereof may be disposed locally (e.g., as part of a local server, a local computing system, etc.) or remotely (e.g., as part of a remote server such as a cloud based server). To that end, a “circuit” as described herein may include components that are distributed across one or more locations.

[0056] Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0057] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0058] It is important to note that the construction and arrangement of the hybrid electric powertrains 300 and 400 as shown in the various exemplary embodiments is illustrative only. Additionally, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. Although only one example of an element from one embodiment that can be incorporated or utilized in another embodiment has been described above, it should be appreciated that other elements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.

[0059] Further, the disclosure includes the following Examples:

Example 1. A hybrid electric powertrain of a vehicle, the powertrain comprising: one or more fuel cells configured to produce a first DC power output; one or more batteries configured to produce a second DC power output; one or more inverters coupled to the one or more fuel cells and the one or more batteries, the one or more inverters configured to convert the first DC power output and the second DC power output to produce one or more AC power outputs; and an AC power bus coupled to the one or more inverters and configured to receive the one or more AC power outputs and provide a AC power output to a motor.

Example 2 The hybrid electric powertrain of Example 1, wherein the hybrid electric powertrain is implemented without the use of DC/DC converters. Example 3. A hybrid electric powertrain of a vehicle, the powertrain comprising: a fuel cell configured to produce a first DC voltage; a battery configured to produce a second DC voltage; an inverter coupled to the fuel cell and the battery, the inverter configured to convert the first DC voltage and the second DC voltage to an AC voltage; an AC power bus coupled to the one or more inverters and configured to provide the AC voltage to a motor; a transformer coupled to the AC power bus configured to convert a voltage output of the AC power bus; and a cycloconverter coupled to the transformer configured to convert a frequency of the voltage output of the AC power bus.

Example 4. The hybrid electric powertrain of Example 3, wherein the cycloconverter comprises one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive a voltage measurement from the inverter; determine one or more control inputs for the motor using a motor control algorithm, the one or more control inputs determined based on: the voltage measurement; and one or more operative conditions of the vehicle; and control operation of the motor to implement the one or more control inputs.

Example 5. The hybrid electric powertrain of Example 3 or 4, wherein the motor is a variable speed traction motor which receives the voltage output of the AC power bus including the converted frequency of the voltage output by the cycloconverter.

Example 6. A method for operating a hybrid electric powertrain in a vehicle, the method comprising: producing a first DC power output from one or more fuel cells; producing a second DC power output from one or more batteries; converting the first DC power output and the second DC power output to produce one or more AC power outputs; and combining the one or more AC power outputs to provide a combined AC power output to a motor.

Example 7. The method of Example 6, wherein the method further comprises: receiving a voltage measurement from one or more inverters; determining one or more control inputs for the motor using a motor control algorithm and based on the voltage measurement and one or more operative conditions of the vehicle; and controlling operation of the motor to implement the one or more control inputs. Example 8. The method of Example 6 or 7, wherein the one or more control inputs include at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus, and wherein the method further comprises: determining the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle; and controlling operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus.

Example 9. The hybrid electric powertrain of Example 1, wherein each of the one or more inverters comprises one or more isolated transformers configured to step-up the AC voltage produced by the one or more inverters.

Example 10. The hybrid electric powertrain of any preceding Example, further comprising a motor control unit coupled to the motor, the motor control unit comprising one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive a voltage measurement from the one or more inverters; determine one or more control inputs for the motor using a motor control algorithm, the one or more control inputs determined based on: the voltage measurement; and one or more operative conditions of the vehicle; and control operation of the motor to implement the one or more control inputs.

Example 11. The hybrid electric powertrain of Example 10, wherein the one or more control inputs include at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus, and wherein the one or more processors are configured to: determine the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle; and control operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus. Example 12. The hybrid electric powertrain of Example 10 or 11, wherein the one or more control inputs includes at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, and/or voltage of the AC power bus.

Example 13. The hybrid electric powertrain of any one of Examples 10 to 12, wherein the motor control unit is integrated into a controller for the inverter.

Example 14. The hybrid electric powertrain of any one of Examples 10 to 13, wherein the one or more operative conditions of the vehicle includes at least one of a speed of the vehicle, a terrain the vehicle is traversing, and an operating mode of the vehicle.

Example 15. The hybrid electric powertrain of any one of Examples 10 to 14, wherein the motor control algorithm includes at least one of vector control, direct torque control, pulse width modulation control, and space vector pulse width modulation control.

Claims

WHAT IS CLAIMED IS:

1. A hybrid electric powertrain of a vehicle, the powertrain comprising: one or more fuel cells configured to produce a first DC power output; one or more batteries configured to produce a second DC power output; one or more inverters coupled to the one or more fuel cells and the one or more batteries, the one or more inverters configured to convert the first DC power output and the second DC power output to produce one or more AC power outputs; and an AC power bus coupled to the one or more inverters and configured to receive the one or more AC power outputs and provide an AC power output to a motor.

2. The hybrid electric powertrain of claim 1, wherein each of the one or more inverters comprises one or more isolated transformers configured to step-up the AC voltage produced by the one or more inverters.

3. The hybrid electric powertrain of claim 1, further comprising a motor control unit coupled to the motor, the motor control unit comprising one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive a voltage measurement from the one or more inverters; determine one or more control inputs for the motor using a motor control algorithm, the one or more control inputs determined based on: the voltage measurement; and one or more operative conditions of the vehicle; and control operation of the motor to implement the one or more control inputs.

4. The hybrid electric powertrain of claim 3, wherein the one or more control inputs include at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus, and wherein the one or more processors are configured to: determine the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle; and control operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus.

5. The hybrid electric powertrain of claim 3, wherein the motor control unit is integrated into a controller for the one or more inverters.

6. The hybrid electric powertrain of claim 3, wherein the one or more operative conditions of the vehicle includes at least one of a speed of the vehicle, a terrain the vehicle is traversing, and an operating mode of the vehicle.

7. The hybrid electric powertrain of claim 3, wherein the motor control algorithm includes at least one of vector control, direct torque control, pulse width modulation control, and space vector pulse width modulation control.

8. The hybrid electric powertrain of claim 1, wherein the hybrid electric powertrain is implemented without the use of DC/DC converters.

9. A hybrid electric powertrain of a vehicle, the powertrain comprising: a fuel cell configured to produce a first DC voltage; a battery configured to produce a second DC voltage; an inverter coupled to the fuel cell and the battery, the inverter configured to convert the first DC voltage and the second DC voltage to an AC voltage; an AC power bus coupled to the one or more inverters and configured to provide the AC voltage to a motor; a transformer coupled to the AC power bus configured to convert a voltage output of the AC power bus; and a cycloconverter coupled to the transformer configured to convert a frequency of the voltage output of the AC power bus.

10. The hybrid electric powertrain of claim 9, wherein the transformer is configured to generate a fixed AC voltage at a constant frequency, and wherein the cycloconverter converts the fixed AC voltage at the constant frequency and outputs a variable AC voltage at a variable frequency.

11. The hybrid electric powertrain of claim 9, wherein the motor control unit is integrated into a controller for the inverter, and wherein the controller for the inverter is communicably coupled with a vehicle control unit and is configured to: determine a desired speed of the motor; and implement the desired speed of the motor via a frequency change to update a speed and a torque of the motor.

12. The hybrid electric powertrain of claim 9, wherein the one or more inverters are coupled to the AC power bus in parallel.

13. The hybrid electric powertrain of claim 9, wherein the motor control unit is communicably coupled to the cycloconverter and is configured to drive one or more control outputs to the cycloconverter to adjust a speed and a torque of the motor.

14. The hybrid electric powertrain of claim 9, wherein the cycloconverter comprises one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive a voltage measurement from the inverter; determine one or more control inputs for the motor using a motor control algorithm, the one or more control inputs determined based on: the voltage measurement; and one or more operative conditions of the vehicle; and control operation of the motor to implement the one or more control inputs.

15. The hybrid electric powertrain of claim 9, wherein the transformer is configured to step up the voltage output of the AC power bus from a lower voltage to a higher voltage, wherein the lower voltage is between 270 volts AC to 800 volts AC and the higher voltage is at least 1300 volts AC.

16. The hybrid electric powertrain of claim 9, wherein the battery generates an output voltage between 270 volts DC to 600 volts DC, wherein the fuel cell generates an output voltage between 600 volts DC to 800 volts DC.

17. The hybrid electric powertrain of claim 9, wherein the motor is a variable speed traction motor which receives the voltage output of the AC power bus including the converted frequency of the voltage output by the cycloconverter.

18. A method for operating a hybrid electric powertrain in a vehicle, the method comprising: producing a first DC power output from one or more fuel cells; producing a second DC power output from one or more batteries; converting the first DC power output and the second DC power output to produce one or more AC power outputs; and combining the one or more AC power outputs to provide a combined AC power output to a motor.

19. The method of claim 18, wherein the method further comprises: receiving a voltage measurement from one or more inverters; determining one or more control inputs for the motor using a motor control algorithm and based on the voltage measurement and one or more operative conditions of the vehicle; and controlling operation of the motor to implement the one or more control inputs.

20. The method of claim 19, wherein the one or more control inputs include at least one of a frequency of the motor, a voltage of a motor, a frequency of the AC power bus, or a voltage of the AC power bus, and wherein the method further comprises: determining the at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus using the motor control algorithm and based on the voltage measurement and the one or more operative conditions of the vehicle; and controlling operation of the motor to implement the determined at least one of the frequency of the motor, the voltage of the motor, the frequency of the AC power bus, or the voltage of the AC power bus.