Power system for transport refrigeration unit and method for controlling the power thereof

Abstract

The subject of the present invention is "Power system for a transport refrigeration unit and method for controlling the power thereof". A power system for a vehicle with a transport refrigeration unit (TRU) is disclosed. The power system includes an energy storage unit suitable for supplying power to the TRU. In addition, the power system includes an axle generator that communicates with the energy storage unit and is suitable for supplying power to the energy storage unit and the TRU. The power system includes a charging system that communicates with the energy storage unit, the axle generator and the TRU. The charging system is configured to monitor the state of charge (SoC) of the energy storage unit and is configured to determine at least one operating characteristic associated with the vehicle. The operating characteristic indicates at least a speed condition of the vehicle. The charging system is configured to control the power supply from the axle generator to the energy storage unit based on the SoC and the operating characteristic.

Description

Technical Field

[0001] The present disclosure relates to vehicles having transport refrigeration units (TRUs), and more particularly to power systems for such vehicles and methods for controlling the supply of power to an energy storage unit of the power system. Background Art

[0002] Vehicles, such as light commercial vehicles (LCVs) or heavy commercial vehicles, are generally deployed for transporting goods via sea, rail or road networks. Such vehicles typically include a cargo container for storing the goods to be transported. In order to maintain the quality of the goods in the cargo container, a refrigeration unit may be deployed to such a cargo container of the vehicle. Typically, the refrigeration unit provides desired environmental parameters, such as temperature, pressure, humidity and other conditions to the cargo container. Such a refrigeration unit is powered by an electric power source, a fuel-based power source or a combination thereof. In addition, a fuel-based power source is also typically used to charge the electric power source and to provide power to the refrigeration unit.

[0003] Currently, the fuel-based power source charges the electric power source to keep its SoC close to or equal to 100%. For example, whenever the SoC of the electric power source drops below 100%, the fuel-based power source is used to maintain the SoC at 100%. Therefore, such a charging strategy results in limited utilization of the electric power source or green energy from the electric power source to supply power to the refrigeration unit. In addition, charging the electric power source whenever the SoC drops below 100% may increase the overall fuel consumption and may be undesirable from a fuel emissions perspective.

[0004] Therefore, it is desirable to provide systems and methods that can allow electrical power sources to discharge to maximize the use of green energy from such sources. Summary of the invention

[0005] This summary is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention nor to determine the scope of the invention.

[0006] In one or more embodiments of the present disclosure, a power system for a vehicle having a transport refrigeration unit (TRU) is disclosed. The power system includes an energy storage unit adapted to supply power to the TRU. In addition, the power system includes an axle generator in communication with the energy storage unit and adapted to supply power to at least one of the energy storage unit and the TRU. The power system includes a charging system in communication with the energy storage unit, the axle generator, and the TRU. The charging system is configured to monitor a state of charge (SoC) of the energy storage unit. In addition, the charging system is configured to determine at least one operating characteristic associated with the vehicle. The at least one operating characteristic indicates at least a speed condition of the vehicle. The charging system is configured to control the power supply from the axle generator to the energy storage unit based on the monitored SoC and the determined operating characteristics.

[0007] In one or more embodiments, the speed condition indicates at least one of an acceleration condition, a deceleration condition, a coasting condition, and a braking condition.

[0008] In one or more embodiments, to control the power supply, the charging system is configured to select a charging strategy from a plurality of charging strategies to charge the energy storage unit based on the monitored SoC and the determined operating characteristics. In addition, the charging system is configured to control the power supply from the axle generator to the energy storage unit based on the selected charging strategy.

[0009] In one or more embodiments, the plurality of charging strategies include at least a reserve charging strategy, an adaptive charging strategy, and a critical charging strategy.

[0010] In one or more embodiments, a charging system includes a battery management controller and a power management controller in communication with each other.

[0011] In one or more embodiments, in order to control the power supply from the axle generator to the energy storage unit based on the selected charging strategy, the charging system is configured to generate an input associated with the selected charging strategy by the battery management controller. The input indicates at least a charging rate and an amount of power to be supplied to the energy storage unit. In addition, the charging system is configured to receive the generated input from the battery management controller by the power management controller. The charging system is configured to control the power supply from the axle generator to the energy storage unit by the power management controller based on the input received from the battery management controller.

[0012] In one or more embodiments, the battery management controller is configured to select a reserve charging strategy if at least: the SoC of the energy storage unit is within a first predetermined range, and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle. The power management controller is configured to limit power supply from the axle generator to the energy storage unit if the reserve charging strategy is selected.

[0013] In one or more embodiments, the battery management controller is configured to select an adaptive charging strategy if at least: the SoC of the energy storage unit is within a second predetermined range, wherein the second predetermined range is lower than the first predetermined range, and the speed condition indicates at least one of an acceleration condition and a gliding condition of the vehicle.

[0014] In one or more embodiments, the power management controller is configured to variably supply power from the axle generator to the energy storage unit if an adaptive charging strategy is selected. The power management controller is configured to vary the torque associated with the axle generator based on the SoC of the energy storage unit to supply variable power to the energy storage unit.

[0015] In one or more embodiments, the battery management controller is configured to select a critical charging strategy if at least: the SoC of the energy storage unit is within a third predetermined range, wherein the third predetermined range is lower than the second predetermined range, and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle. The power management controller is configured to allow maximum power supply from the axle generator to the energy storage unit if the critical charging strategy is selected.

[0016] In one or more embodiments, the battery management controller is configured to allow power supply from the axle generator to the energy storage unit if at least: the SoC of the energy storage unit is less than 100%, and the speed condition indicates at least one of a braking condition and a deceleration condition.

[0017] In one or more embodiments, the energy storage unit includes at least one of a battery and a flow battery.

[0018] In one or more embodiments, a method of controlling power supply to an energy storage unit of a vehicle having a transport refrigeration unit (TRU) is disclosed. The method includes monitoring a state of charge (SoC) of the energy storage unit. In addition, the method includes determining at least one operating characteristic associated with the vehicle. The at least one operating characteristic indicates at least a speed condition of the vehicle. The method includes controlling power supply from an axle generator of the vehicle to the energy storage unit to charge the energy storage unit based on the monitored SoC and the determined operating characteristic.

[0019] In one or more embodiments, controlling the power supply further includes: selecting a charging strategy from a plurality of charging strategies to charge the energy storage unit based on the monitored SoC and the determined operating characteristics, and controlling the power supply from the axle generator to the energy storage unit based on the selected charging strategy.

[0020] In one or more embodiments, the speed condition indicates at least one of an acceleration condition, a deceleration condition, a coasting condition, and a braking condition, and the plurality of charging strategies include at least a reserve charging strategy, an adaptive charging strategy, and a critical charging strategy.

[0021] In one or more embodiments, controlling the supply of power from the axle generator to the energy storage unit based on the selected charging strategy further includes: generating, by the battery management controller, an input associated with the selected charging strategy, receiving, by the power management controller, the generated input from the battery management controller, and controlling, by the power management controller, the supply of power from the axle generator to the energy storage unit based on the input received from the battery management controller. The input indicates at least a charging rate and an amount of power to be supplied to the energy storage unit.

[0022] In one or more embodiments, the method includes selecting, by a battery management controller, a reserve charging strategy if at least: a SoC of the energy storage unit is within a first predetermined range, and a speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle. In the reserve charging strategy, power supply is limited from the axle generator to the energy storage unit.

[0023] In one or more embodiments, the method includes selecting, by the battery management controller, an adaptive charging strategy if at least: the SoC of the energy storage unit is within a second predetermined range, wherein the second predetermined range is lower than the first predetermined range, and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle. In the adaptive charging strategy, the power supplied from the axle generator to the energy storage unit is varied.

[0024] In one or more embodiments, the method includes selecting, by the battery management controller, a critical charging strategy if at least: the SoC of the energy storage unit is within a third predetermined range, wherein the third predetermined range is lower than the second predetermined range, and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle. In the critical charging strategy, maximum power is supplied from the axle generator to the energy storage unit.

[0025] In one or more embodiments, the method includes allowing, by a battery management controller, power supply from the axle generator to the energy storage unit if at least: the SoC of the energy storage unit is less than 100%, and the speed condition indicates at least one of a braking condition and a deceleration condition.

[0026] In order to further illustrate the advantages and features of the method, system and device / apparatus, a more specific description of the method, system and device / apparatus will be presented by reference to the specific embodiments thereof illustrated in the accompanying drawings. It is appreciated that these drawings depict only typical embodiments of the present disclosure and therefore should not be considered as limiting the scope thereof. The present disclosure will be described and explained using the accompanying drawings, using additional features and details. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and other features, aspects and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein like reference numerals refer to like parts throughout the drawings, and wherein:

[0028] Figure 1 illustrates a perspective view of a vehicle having a transport refrigeration unit (TRU) according to one or more embodiments of the present disclosure;

[0029] Figure 2 illustrates a block diagram of a power system deployed in a vehicle according to one or more embodiments of the present disclosure;

[0030] Figure 3a-3d illustrates the operation of a charging system of a power system supplying power to an energy storage unit of the power system according to one or more embodiments of the present disclosure;

[0031] Figure 4 illustrates an exemplary graph depicting the SoC of an energy storage unit and the corresponding torque associated with an axle generator for charging the energy storage unit according to one or more embodiments of the present invention; and

[0032] Figure 5 A flow chart depicting a method for controlling power supply to an energy storage unit of a vehicle is illustrated in accordance with one or more embodiments of the present disclosure.

[0033] Furthermore, those skilled in the art will appreciate that the elements in the drawings are illustrated for simplicity and may not necessarily have been drawn to scale. For example, a flow chart illustrates the method in terms of the most significant steps involved to help improve understanding of aspects of the present disclosure. Furthermore, with respect to the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details relevant to understanding the embodiments of the present disclosure so as not to obscure the drawings with details that would be readily apparent to one of ordinary skill in the art having the benefit of the description herein. DETAILED DESCRIPTION

[0034] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to various embodiments, and specific language will be used to describe the embodiments. It will be understood, however, that no limitation of the scope of the present disclosure is thereby intended, and such changes and further modifications in the illustrated systems and devices, and such further applications of the principles of the present disclosure as illustrated therein are contemplated as would normally occur to one skilled in the art to which the present disclosure relates.

[0035] It will be understood by those skilled in the art that both the foregoing general description and the following detailed description are illustrative of the present disclosure and are not intended to limit the present disclosure.

[0036] Throughout this specification, references to "aspect," "another aspect," or similar language mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, throughout this specification, appearances of the phrases "in an embodiment," "in another embodiment," "some embodiments," "one or more embodiments," and similar language may, but do not necessarily, all refer to the same embodiment.

[0037] The terms "comprises, comprising" or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process or method that includes a series of steps includes not only those steps but may also include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or subsystems or elements or structures or components beginning with "comprises ..." do not exclude the presence of other devices or other subsystems or other elements or other structures or other components or additional devices or additional subsystems or additional elements or additional structures or additional components without more limitations.

[0038] The term "unit" used herein may imply a unit including, for example, one of hardware, software, and firmware, or a combination of two or more thereof. "Unit" may be used interchangeably with terms such as logic, logic block, component, circuit, etc. A "unit" may be a minimum system component for performing one or more functions, or may be a part thereof.

[0039] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0040] Typically, in a vehicle with a transport refrigeration unit (TRU), the electric power source is charged when power from a fuel-based power source is available and the state of charge (SoC) of the electric power source is less than 100%. In addition, if a fuel-based power source is available, the refrigeration unit is powered by the fuel-based power source regardless of the SoC of the electric power source. For example, a fuel-based power source is superior to an electric power source, even if the SoC of the electric power source is sufficient to supply power to the refrigeration unit. Therefore, such a charging and power supply strategy results in limited use of the electric power source or green energy from the electric power source to supply power to the refrigeration unit. In addition, long-term operation of an electric power source (such as a battery) at close to 100% SoC reduces the possibility of capturing green regenerative braking energy. In addition, the aforementioned charging strategy also exacerbates battery capacity loss and accelerates aging of the electric power source.

[0041] The present disclosure provides a power system for a vehicle and a method for controlling power supply to an energy storage unit (such as an electric power source) of the power system. The power system may include a charging system that is capable of selecting different charging strategies based on the SoC of the energy storage unit and the speed conditions of the vehicle (such as acceleration, deceleration, coasting, and braking). In addition, based on the selected charging strategy, the electric storage unit can be charged by using power from a fuel-based power source (such as an axle generator). The implementation of different charging strategies helps to increase the utilization of the electric storage unit and minimize fuel consumption when charging the electric storage unit.

[0042] Figure 1 A perspective view of a vehicle 100 having a transport refrigeration unit (TRU) 102 is illustrated in accordance with one or more embodiments of the present disclosure. In one embodiment, the vehicle 100 may be embodied as a fuel-based vehicle having an internal combustion engine, which may be part of a powertrain or drive system of such a vehicle. In another embodiment, the vehicle 100 may be embodied as an electric vehicle having an electric motor to provide propulsion for traversing such a vehicle. In yet another embodiment, the vehicle 100 may be embodied as a hybrid vehicle having a combination of an internal combustion engine and one or more electric motors.

[0043] refer to Figure 1 , the vehicle 100 may include a cab 104, a container 106, a TRU 102, and a power system 108. The cab 104 may be located at the front of the vehicle 100 and coupled to the container 106. In an embodiment, the container 106 may be pulled by the vehicle 100. It is understood that the embodiments described herein may be applied to shipping containers via rail, sea, air, or any other suitable container transportation, and thus the vehicle 100 may be a truck, train, ship, airplane, helicopter, etc. The container 106 may be coupled to the vehicle 100 and thus pulled or propelled to a desired destination.

[0044] In an embodiment, the container 106 may include a top wall 110, a bottom wall 112 opposite and spaced from the top wall 110, a pair of side walls 114 spaced from each other and opposite, and a front wall 116 and a rear wall 118 spaced from each other and opposite. The front wall 116 may be closest to the vehicle 100. The container 106 may further include a door (not shown) at the rear wall 118 or any other wall. The walls 110, 112, 114, 116, 118 may together define the boundaries of a cargo compartment within the container 106.

[0045] In one or more embodiments, the vehicle 100 can be used to transport and distribute goods, such as perishable goods and environmentally sensitive goods, referred to herein as perishable goods. Perishable goods may include, but are not limited to, fruits, vegetables, grains, beans, nuts, eggs, dairy products, seeds, flowers, meat, poultry, fish, ice, blood, pharmaceuticals, and any other suitable goods that require cold chain transportation.

[0046] In the illustrated embodiment, the TRU 102 may be coupled to the container 106 and located on the front wall 116 of the container 106. The TRU 102 may be adapted to provide desired environmental parameters such as temperature, pressure, humidity, carbon dioxide, ethylene, ozone, light, vibration exposure, and other conditions to the cargo compartment of the container 106. In one or more embodiments, the TRU 102 may be embodied as a refrigeration system capable of providing a desired temperature range and humidity range. Although in the illustrated embodiment, the implementation of the power system 108 is explained with respect to the vehicle 100 having the TRU 102. This should not be construed as limiting, and the power system 108 may also be implemented in a vehicle 100 without the TRU 102 and having at least one electric power source.

[0047] In one or more embodiments, the TRU 102 may include, but is not limited to, a compressor, an electric compressor motor, a condenser that may be air cooled, a condenser fan assembly, a receiver, a filter drier, a heat exchanger, an expansion valve, an evaporator, an evaporator fan assembly, a suction regulating valve, and a controller that may include a computer-based processor (e.g., a microprocessor). Figure 1 , the TRU 102 may be in communication with a power system 108 of the vehicle 100. The power system 108 may be configured to supply power for operating the TRU 102 or at least the aforementioned components of the TRU 102.

[0048] Reference to the present disclosure Figure 2-5 The construction and operating details of the power system 108 are explained in detail.

[0049] Figure 2A block diagram of a power system 108 deployed in a vehicle 100 according to one or more embodiments of the present disclosure is illustrated. In the illustrated embodiment, the power system 108 may include, but is not limited to, an electronic driver 202, an energy storage unit 204, and a charging system 206. The electronic driver 202, the energy storage unit 204, and the charging system 206 may communicate with each other and with the TRU 102. As previously mentioned, the power system 108 may be configured to supply power to the TRU 102. In one or more embodiments, the electronic driver 202 and the energy storage unit 204 may be configured to selectively supply power to the TRU 102.

[0050] In the illustrated embodiment, the electronic drive 202 may include, but is not limited to, an axle generator 208 and an inverter 210. The axle generator 208 may communicate with the energy storage unit 204 and may be adapted to supply power to at least one of the energy storage unit 204 and the TRU 102. The axle generator 208 may be mounted on an axle or a wheel hub of the vehicle 100. The axle generator 208 may be configured to recover rotational energy from the axle or the wheel hub when the vehicle 100 is moving. For example, the axle generator 208 may be configured to recover rotational energy when the axle of the vehicle 100 is rotating due to acceleration, deceleration, coasting, or braking. In addition, the axle generator 208 may be configured to convert the recovered rotational energy into electrical energy, referred to herein as power.

[0051] In the illustrated embodiment, the axle generator 208 may be embodied as an alternating current (AC) generator configured to convert rotational energy into AC power. The axle generator 208 may be asynchronous or synchronous. In such an embodiment, the inverter 210 may communicate with the axle generator 208 and be configured to receive AC power from the axle generator 208. The inverter 210 may be configured to convert AC power into direct current (DC) power. In one or more embodiments, the inverter 210 of the electronic drive 202 may include, but is not limited to, a voltage control function, a current control function, and a frequency converter. In one or more embodiments, the axle generator 208 may be embodied as a DC generator without departing from the scope of the present disclosure.

[0052] In addition, a main inverter 212 may be deployed to convert DC power from the electronic drive 202 into AC power. In one or more embodiments, the main inverter 212 may be a standalone unit or integrated with the TRU 102. In the illustrated embodiment, the power system 108 may include the main inverter 212 and be electrically coupled to the inverter 210 of the electronic drive 202 and the TRU 102. The main inverter 212 may be configured to convert DC power received from the inverter 210 of the electronic drive 202 into AC power. Subsequently, the main inverter 212 may be configured to supply the converted AC power to the TRU 102.

[0053] refer to Figure 2 , the energy storage unit 204 may communicate with the charging system 206 and be electrically coupled to the electronic drive 202. In addition, the energy storage unit 204 may be electrically coupled to the TRU 102 and adapted to supply power to the TRU 102. In one or more embodiments, the energy storage unit 204 may include at least one of a battery and a flow battery. The energy storage unit 204 may be configured to receive power from the electronic drive 202. In particular, the energy storage unit 204 may be charged by the electronic drive 202 and store energy to be selectively supplied to the TRU 102. In the illustrated embodiment, the energy storage unit 204 may be electrically coupled to the main inverter 212 via a DC / DC boost converter 214. The DC / DC boost converter 214 may be configured to regulate the output voltage of the energy storage unit 204. For example, the DC / DC boost converter 214 may increase the output voltage of the energy storage unit 204.

[0054] As previously explained, the charging system 206 may communicate with the energy storage unit 204, the axle generator 208, and the TRU 102. In an embodiment, the charging system 206 may be configured to control the flow of power supply from the electric drive 202 to the TRU 102 and the energy storage unit 204. Figure 2 In the illustrated embodiment, the charging system 206 may include, but is not limited to, a power management controller 216 and a battery management controller 218. The power management controller 216 may be interchangeably referred to as the controller 216 without departing from the scope of the present disclosure. In one or more embodiments, the controller 216 may be embodied as a TRU controller or a stand-alone controller. Operational aspects of the charging system 206 may be explained with respect to the controller 216 embodied as a TRU controller 216. However, this should not be construed as limiting, and the controller 216 embodied as a stand-alone controller may also be implemented in the charging system 206.

[0055] The TRU controller 216 may communicate with the electronic driver 202, the TRU 102, and the battery management controller 218. In one or more embodiments, the communication between various components (such as the TRU controller 216, the electronic driver 202, the TRU 102, the energy storage unit 204, and the battery management controller 218) may be embodied as wireless communication or wired communication. Without departing from the scope of the present disclosure, the aforementioned components may communicate with each other via a communication interface, including but not limited to a controller area network (CAN).

[0056] In one or more embodiments, each of the TRU controller 216 and the battery management controller 218 may include a processor, a memory, a module, and data. The module and the memory are coupled to the processor. The processor may be a single processing unit or multiple units, all of which may include multiple computing units. The processor may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operating instructions. Among other capabilities, the processor is configured to retrieve and execute computer-readable instructions and data stored in the memory.

[0057] The memory may include any non-transitory computer-readable medium known in the art, including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and / or non-volatile memory, such as read-only memory (ROM), erasable programmable ROM, flash memory, hard disks, optical disks, and tapes.

[0058] Modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement data types. Modules may also be implemented as (one or more) signal processors, (one or more) state machines, logic circuits, and / or any other devices or components that manipulate signals based on operational instructions.

[0059] In addition, the module can be implemented with hardware, instructions executed by a processing unit, or a combination thereof. The processing unit may include a computer, a processor such as a processor, a state machine, a logic array, or any other suitable device capable of processing instructions. The processing unit may be a general-purpose processor that executes instructions to enable a general-purpose processor to perform the required tasks, or the processing unit may be dedicated to performing the required functions. In another aspect of the present disclosure, a module may be a machine-readable instruction (software) that, when executed by a processor / processing unit, performs any of the described functionality.

[0060] In one or more embodiments, the TRU controller 216 may be a standalone unit or integrated with the TRU 102 without departing from the scope of the present disclosure. The TRU controller 216 may be configured to receive various inputs indicative of the operating state of the TRU 102 and determine the power demand of the TRU 102. Based on the power demand, the TRU controller 216 may be configured to direct the power supply from the electronic driver 202 to the TRU 102. In one or more embodiments, the TRU controller 216 may communicate with a plurality of sensors of the TRU 102, such as temperature sensors, and may be configured to estimate the power demand of the TRU 102 based on the inputs received from the plurality of sensors of the TRU 102. Based on the estimated power demand, the TRU controller 216 may be configured to direct the power supply from the electronic driver 202 to the TRU 102. Furthermore, the TRU controller 216 may be configured to receive input indicative of an operating state of the energy storage unit 204 and accordingly be configured to direct at least a portion of the power supply from the electronic drive 202 to the energy storage unit 204 for charging the energy storage unit 204 .

[0061] In one or more embodiments, based on the power demand, the TRU controller 216 can determine whether only the axle generator 208 can meet the power demand of the TRU 102. If the axle generator 208 can meet the power demand of the TRU 102, the remaining power can be used to charge the energy storage unit 204, as explained in a subsequent section of this disclosure. In addition, if the axle generator 208 can only partially meet the power demand of the TRU 102, the remaining power is supplied to the TRU 102 from the energy storage unit 204. In addition, if the axle generator 208 cannot meet the power demand of the TRU 102, the power demand of the TRU 102 can be met by the energy storage unit 204.

[0062] In one or more embodiments, the charging system 206 may be configured to monitor the state of charge (SoC) of the energy storage unit 204. In addition, the charging system 206 may be configured to determine at least one operating characteristic associated with the vehicle 100. The charging system 206 may be configured to control the supply of power from the axle generator 208 to the energy storage unit 204 based on the monitored SoC and the determined operating characteristic. The construction and operating details of the charging system 206 are explained in detail in subsequent sections of this disclosure.

[0063] As previously mentioned, the charging system 206 may include a battery management controller 218 in communication with the TRU controller 216 and the energy storage unit 204. In one or more embodiments, the battery management controller 218 may be a standalone unit or integrated with the energy storage unit 204. The battery management controller 218 may be configured to determine parameters associated with the operating state of the energy storage unit 204. In an embodiment, the battery management controller 218 may be configured to monitor the SoC of the energy storage unit 204.

[0064] In addition, the battery management controller 218 may be configured to determine at least one operating characteristic associated with the vehicle 100. The at least one operating characteristic may indicate at least a speed condition of the vehicle 100. In one or more embodiments, the speed condition may indicate at least one of an acceleration condition, a deceleration condition, a coasting condition, and a braking condition. In one or more embodiments, the battery management controller 218 may communicate with a sensing system 220 of the vehicle 100. In such an embodiment, the battery management controller 218 may be configured to receive input indicating at least a speed condition of the vehicle 100. In one or more examples, the input may include data associated with vehicle speed, clutch switch, brake switch, cruise control, accelerator pedal position, wheel speed, speed of the axle generator 208, and engine speed. The sensing system 220 may include, but is not limited to, an accelerometer, a fleet management system (FMS), and / or an electronic braking system (EBS) without departing from the scope of the present disclosure.

[0065] As previously mentioned, based on the monitored SoC and the determined operating characteristics, the charging system 206 can be configured to control the power supply from the axle generator 208 to the energy storage unit 204. In one or more embodiments, the battery management system 218 can be configured to select a charging strategy from a plurality of charging strategies to charge the energy storage unit 204 based on the monitored SoC and the determined operating characteristics. In one or more embodiments, the plurality of charging strategies may include at least a reserve charging strategy, an adaptive charging strategy, and a critical charging strategy. In one embodiment, data associated with the plurality of charging strategies may be stored in a memory of the battery management controller 218. In another embodiment, data associated with the plurality of charging strategies may be stored in a remote server, such as a cloud server, that communicates with the battery management controller 218. The data associated with each of the plurality of charging strategies may indicate a charging rate and an amount of power to be supplied to the energy storage unit 204.

[0066] In addition, the charging system 206 can be configured to control the power supply from the axle generator 208 to the energy storage unit 204 based on the selected charging strategy. In an embodiment, the TRU controller 216 can be configured to control the power supply to the energy storage unit 204 based on the selected charging strategy. In one or more embodiments, the battery management controller 218 can be configured to generate inputs associated with the selected charging strategy. The inputs can indicate at least a charging rate and an amount of power to be supplied to the energy storage unit 204.

[0067] In addition, the TRU controller 216 may be configured to receive the generated input from the battery management controller 218. Thereafter, the TRU controller 216 may be configured to control the power supply from the axle generator 208 to the energy storage unit 204 based on the input received from the battery management controller 218. For example, based on the generated input received from the battery management controller 218, the TRU controller 216 may be configured to adjust at least the voltage control function, the current control function, and the frequency converter of the inverter 210 of the electronic drive 202 in order to control the power supply from the axle generator 208 to the energy storage unit 204.

[0068] In one or more embodiments, the TRU controller 216 may be configured to prioritize the supply of power to the TRU 102 over the supply of power to the energy storage unit 204. For example, the TRU controller 216 may be configured to determine whether the TRU 102 is operational, and if the TRU 102 is operational, power may be primarily supplied to the TRU 102 from the electronic drive 202. Thereafter, the TRU controller 216 may be configured to control the supply of the remaining power from the electronic drive 202 to the energy storage unit 204 based on the selected charging strategy. Thus, in such an embodiment, the TRU controller 216 may be configured to prioritize meeting the power requirements of the TRU 102 and secondarily meet the charging requirements of the energy storage unit 204. However, this should not be construed as limiting, and the TRU 102 may also be configured to prioritize charging the energy storage unit 204 over supplying power to the TRU 102 without departing from the scope of the present disclosure.

[0069] In one or more embodiments, in addition to the electronic drive 202 and the energy storage unit 204, a power grid (not shown) may be employed as a power source. In such an embodiment, when the vehicle 100 is in an idle condition (such as a parking condition), the power grid may be electrically connected to the energy storage unit 204 and the TRU 102. In one embodiment, the TRU controller 216 may be configured to control the power flow to the TRU 102 based on the power demand of the TRU 102, and the remaining power may be supplied to the energy storage unit 204 based on its SoC. For example, if the TRU 102 is operational and the power grid is connected, the TRU controller 216 may control the power flow to the TRU 102 to meet the power demand. Thereafter, based on the monitored SoC received from the battery management controller 218, the TRU controller 216 may control the flow of the remaining power to the energy storage unit 204. For example, if the SoC is less than 100%, the energy storage unit 204 may be charged using the remaining power from the power grid.

[0070] The details of the operation of the power system 108 for each charging strategy are described in detail in the relevant section of the present disclosure. Figure 3a-3d This is explained in detail in the subsequent sections.

[0071] Figure 3a-3d The operation of the charging system 206 of the power system 108 supplying power to the energy storage unit 204 of the power system 108 according to one or more embodiments of the present disclosure is illustrated. In one or more embodiments, the battery management controller 218 may be configured to select a reserve charging strategy if at least the SoC of the energy storage unit 204 is within a first predetermined range and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle 100.

[0072] refer to Figure 3a , the battery management controller 218 may be configured to monitor the SoC of the energy storage unit 204. Based on the monitored SoC, the battery management controller 218 may be configured to determine whether the SoC is within a first predetermined range. In an example, the first predetermined range may be 80% SoC-100% SoC without departing from the scope of the present disclosure. In one or more embodiments, the first predetermined range may vary based on various factors, such as the capacity of the energy storage unit 204 and based on user needs / applications. Therefore, it should not be interpreted as limiting, and the first predetermined range may be embodied as any range other than 80% SoC-100% SoC without departing from the scope of the present disclosure. In one example, if the application requires the vehicle 100 to cruise at a low speed, the first predetermined range may be reduced to 90% SoC-100% SoC. In another example, if the application requires the vehicle 100 to cruise at a higher speed, the first predetermined range may be increased to 70% SoC-100% SoC.

[0073] Additionally, the battery management controller 218 may be configured to receive input from the sensing system 220. The input may be associated with at least one operating characteristic indicative of a speed condition, such as an acceleration condition, a coasting condition, a deceleration condition, and a braking condition. Figure 3a Based on input from the sensing system 220, the battery management controller 218 can determine whether the speed condition is one of an acceleration condition and a coasting condition.

[0074] Now, if the monitored SoC of the energy storage unit 204 is within the first predetermined range, and the speed condition is determined to be one of the acceleration condition and the coasting condition, the battery management controller 218 may select a reserve charging strategy from a plurality of charging strategies. Subsequently, the battery management controller 218 may generate an input associated with the reserve charging strategy. The input may indicate at least a charging rate and an amount of power to be supplied to the energy storage unit 204. In the reserve charging strategy, the charging rate and the amount of power to be supplied from the electronic drive 202 may be substantially equal to zero. In particular, in the reserve charging strategy, power may not be supplied from the axle generator 208 to the energy storage unit 204.

[0075] In addition, the TRU controller 216 may receive input from the battery management controller 218 indicating the generation of a reserve charging strategy. If the reserve charging strategy is selected, the TRU controller 216 may be configured to limit the power supply from the axle generator 208 to the energy storage unit 204. In one or more embodiments, the TRU controller 216 may determine whether the TRU 102 is operational. If the TRU 102 is operational, the TRU controller 216 may determine the power demand of the TRU 102. Now, based on the power demand of the TRU 102, the TRU controller 216 may direct the power supply from the axle generator 208 to the TRU 102. In addition, in one or more embodiments, the TRU controller 216 may be configured to determine whether grid power (such as a shore-based power source) is connected to the vehicle 100. The shore-based power source may refer to a power source connected to the vehicle 100 in a parking condition. If the grid power is connected, the TRU controller 216 may direct the power supply mainly from the grid power to the TRU 102 based on the power demand of the TRU 102. The TRU controller 216 may then direct the remaining power from the grid power to charge the energy storage unit 204 in a reverse charging strategy.

[0076] refer to Figure 3b, the battery management controller 218 can be configured to monitor the SoC of the energy storage unit 204. Based on the monitored SoC, the battery management controller 218 can be configured to determine whether the SoC is within a second predetermined range. The second predetermined range may be lower than the first predetermined range. In an example, the second predetermined range may be 60% SoC-80% SoC without departing from the scope of the present disclosure. In one or more embodiments, the second predetermined range may vary based on various factors, such as the capacity of the energy storage unit and based on user needs / applications. Therefore, it should not be interpreted as limiting, and the second predetermined range may be embodied as any range other than 60% SoC-80% SoC without departing from the scope of the present disclosure.

[0077] Additionally, the battery management controller 218 may be configured to receive input from the sensing system 220. The input may be associated with the at least one operating characteristic indicative of a speed condition, such as an acceleration condition, a coasting condition, a deceleration condition, and a braking condition. Figure 3b Based on input from the sensing system 220, the battery management controller 218 can determine whether the speed condition is one of an acceleration condition and a coasting condition.

[0078] Now, if the monitored SoC of the energy storage unit 204 is within the second predetermined range, and the speed condition is determined to be one of the acceleration condition and the coasting condition, the battery management controller 218 may select an adaptive charging strategy from a plurality of charging strategies. Subsequently, the battery management controller 218 may generate an input associated with the adaptive charging strategy. The input may indicate at least a charging rate and an amount of power to be supplied to the energy storage unit 204. In the adaptive charging strategy, the charging rate and the amount of power to be supplied from the electronic drive 202 may vary based on a change in the SoC of the energy storage unit 204 between the second predetermined range. In particular, in the adaptive charging strategy, the power supply from the axle generator 208 may gradually increase as the SoC of the energy storage unit 204 decreases, and gradually decrease as the SoC of the energy storage unit 204 increases.

[0079] In addition, the TRU controller 216 may receive input indicating generation of an adaptive charging strategy from the battery management controller 218. In one or more embodiments, if the adaptive charging strategy is selected, the TRU controller 216 may be configured to variably supply power from the axle generator 208 to the energy storage unit 204. The TRU controller 216 may be configured to change the torque associated with the axle generator 208 based on the SoC of the energy storage unit 204 to supply variable power to the energy storage unit 204. In one or more embodiments, based on the SoC of the energy storage unit 204, the TRU controller 216 may be configured to adjust at least the voltage control function, the current control function, and the frequency converter of the inverter 210 of the electronic drive 202 to change the power supply from the axle generator 208 to the energy storage unit 204. For example, the TRU controller 216 may change the torque associated with the axle generator 208 by adjusting at least the voltage control function, the current control function, and the frequency converter to change the power supply to the energy storage unit 204.

[0080] In one or more embodiments, the TRU controller 216 may determine whether the TRU 102 is operational. If the TRU 102 is operational, the TRU controller 216 may determine the power demand of the TRU 102. Now, based on the power demand of the TRU 102, the TRU controller 216 may direct the power supply from the axle generator 208 to the TRU 102. Subsequently, when the power demand of the TRU 102 is met, the TRU controller 216 may change and direct the remaining power to charge the energy storage unit 204 based on the SoC of the energy storage unit 204 in an adaptive charging strategy.

[0081] refer to Figure 3c , the battery management controller 218 can be configured to monitor the SoC of the energy storage unit 204. Based on the monitored SoC, the battery management controller 218 can be configured to determine whether the SoC is within a third predetermined range. The third predetermined range may be lower than the second predetermined range. In an example, the third predetermined range may be 20% SoC-60% SoC without departing from the scope of the present disclosure. In one or more embodiments, the third predetermined range may vary based on various factors, such as the capacity of the energy storage unit 204 and based on user needs / applications. Therefore, it should not be interpreted as limiting, and the third predetermined range may be embodied as any range other than 20% SoC-60% SoC without departing from the scope of the present disclosure.

[0082] Additionally, the battery management controller 218 may be configured to receive input from the sensing system 220. The input may be associated with the at least one operating characteristic indicative of a speed condition, such as an acceleration condition, a coasting condition, a deceleration condition, and a braking condition. Figure 3cBased on input from the sensing system 220, the battery management controller 218 can determine whether the speed condition is one of an acceleration condition and a coasting condition.

[0083] Now, if the monitored SoC of the energy storage unit 204 is within the third predetermined range, and the speed condition is determined to be one of the acceleration condition and the coasting condition, the battery management controller 218 may select a critical charging strategy from a plurality of charging strategies. Subsequently, the battery management controller 218 may generate an input associated with the critical charging strategy. The input may indicate at least a charging rate and an amount of power to be supplied to the energy storage unit 204. In the critical charging strategy, the charging rate and the amount of power to be supplied from the electronic drive 202 may be substantially equal to the maximum charging rate and the maximum amount of power to be supplied. In particular, in the critical charging strategy, the power supply from the axle generator 208 may be embodied as a maximum power supply.

[0084] In addition, the TRU controller 216 may receive input from the battery management controller 218 indicating the generation of a critical charging strategy. In one or more embodiments, if the critical charging strategy is selected, the TRU controller 216 may be configured to allow maximum power supply from the axle generator 208 to the energy storage unit 204. The TRU controller 216 may be configured to maximize the torque associated with the axle generator 208 to supply maximum power to the energy storage unit 204. In one or more embodiments, the TRU controller 216 may be configured to adjust at least the voltage control function, the current control function, and the frequency converter of the inverter 210 of the electronic drive 202 to maximize the power supply from the axle generator 208 to the energy storage unit 204. For example, the TRU controller 216 may maximize the torque associated with the axle generator 208 by adjusting at least the voltage control function, the current control function, and the frequency converter to maximize the power supply to the energy storage unit 204.

[0085] In one or more embodiments, the TRU controller 216 may determine whether the TRU 102 is operational. If the TRU 102 is operational, the TRU controller 216 may determine the power demand of the TRU 102. Now, based on the power demand of the TRU 102, the TRU controller 216 may direct the maximum power supply from the axle generator 208 to the TRU 102. Subsequently, when the power demand of the TRU 102 is met, the TRU controller 216 may direct the maximum power supply for charging the energy storage unit 204 in a critical charging strategy.

[0086] refer to Figure 3d, the battery management controller 218 can be configured to monitor the SoC of the energy storage unit 204. Based on the monitored SoC, the battery management controller 218 can be configured to determine whether the SoC is less than 100%. In addition, the battery management controller 218 can be configured to receive input from the sensing system 220. The input can be associated with at least one operating characteristic indicating a speed condition, such as an acceleration condition, a coasting condition, a deceleration condition, and a braking condition. Figure 3d Based on the input from the sensing system 220, the battery management controller 218 can determine whether the speed condition is one of a deceleration condition and a braking condition.

[0087] Now, if the monitored SoC of the energy storage unit 204 is less than 100% and the speed condition is determined to be one of the deceleration condition and the braking condition, the battery management controller 218 may allow power supply from the axle generator 208 to the energy storage unit 204. In particular, when the SoC is less than 100% and the speed condition is determined to be one of the deceleration condition and the braking condition, the TRU controller 216 may transfer the maximum power from the axle generator 208 to the energy storage unit 204. The charging rate and the amount of power to be supplied from the axle generator 208 to the energy storage unit 204 may be substantially equal to the maximum charging rate and the maximum power amount.

[0088] In one or more embodiments, the TRU controller 216 may determine whether the TRU 102 is operational. If the TRU 102 is operational, the TRU controller 216 may determine the power demand of the TRU 102. Now, based on the power demand of the TRU 102, if the speed condition is determined to be one of a deceleration condition and a braking condition, the TRU controller 216 may direct the maximum power supply from the axle generator 208 to the TRU 102. Subsequently, when the power demand of the TRU 102 is met, if the SoC is less than 100% and the speed condition is one of a deceleration condition and a braking condition, the TRU controller 216 may direct the maximum power supply to be used for charging the energy storage unit 204.

[0089] Figure 4 An exemplary graph 400 depicting the SoC of the energy storage unit and the corresponding torque associated with the axle generator 208 for charging the energy storage unit 204 is shown in accordance with one or more embodiments of the present disclosure. Figure 4 , a SoC range of 100%-80% indicates a first predetermined range 402. As previously explained, if the vehicle 100 is moving, ie, accelerating or coasting, and the SoC is within the first predetermined range, the energy storage unit 204 may not be charged using the power supply from the axle generator 208.

[0090] In addition, the SoC range of 80%-60% indicates the second predetermined range 404. As previously explained, if the vehicle 100 is moving, i.e., accelerating or coasting, and the SoC is within the second predetermined range, the energy storage unit 204 can be charged using the power supply from the axle generator 208. In particular, the TRU controller 216 can change the power supply by changing the torque associated with the axle generator 208 based on the SoC of the energy storage unit 204. For example, referring to the curve 406, as the SoC of the energy storage unit 204 increases, the TRU controller 216 can gradually reduce the torque. In particular, when the SoC of the energy storage unit 204 is 60%, the TRU controller 216 can maximize the torque associated with the axle generator 208 to supply power for charging the energy storage unit 204. Subsequently, when the SoC of the energy storage unit 204 increases to 70%, the TRU controller 216 can gradually reduce the torque to supply less power to the energy storage unit 204 compared to the power supplied when the SoC is equal to 60%.

[0091] In addition, the SoC range of 60%-20% indicates a third predetermined range 408. As previously explained, if the vehicle 100 is moving, i.e., accelerating or coasting, and the SoC is within the third predetermined range, the energy storage unit 204 can be charged using the maximum power supply from the axle generator 208. Referring to curve 410, when the SoC of the energy storage unit 204 is between 60%-20%, the TRU controller 216 can maximize the torque associated with the axle generator 208, such as 86Nm, to supply maximum power to the energy storage unit 204. When the SoC is within the range of 20%-60%, the TRU controller 216 can maintain the maximum torque associated with the axle generator 208. It should be understood that the maximum torque mentioned in the present disclosure and in Figure 4 The SoC ranges and torque values ​​illustrated in are exemplary in nature and should not be construed as limiting.

[0092] Figure 5 A flow chart depicting a method 500 for controlling power supply to an energy storage unit 204 of a power system 108 is illustrated in accordance with one or more embodiments of the present disclosure. At step 502, the method 500 includes monitoring a state of charge (SoC) of the energy storage unit 204. At step 504, the method 500 includes determining at least one operating characteristic associated with the vehicle 100. The at least one operating characteristic may indicate at least a speed condition of the vehicle 100.

[0093] At step 506, the method 500 includes controlling the supply of power from the axle generator 208 of the vehicle 100 to the energy storage unit 204 based on the monitored SoC and the determined operating characteristics to charge the energy storage unit 204. In one or more embodiments, to control the supply of power, the method 500 may include selecting a charging strategy from a plurality of charging strategies based on the monitored SoC and the determined operating characteristics to charge the energy storage unit 204. Furthermore, the method 500 may include controlling the supply of power from the axle generator 208 to the energy storage unit 204 based on the selected charging strategy.

[0094] In one or more embodiments, to control the power supply based on the selected charging strategy, the method 500 may include generating, by the battery management controller 218, inputs associated with the selected charging strategy. Additionally, the method 500 may include receiving, by the TRU controller 216, the generated inputs from the battery management controller 218. Additionally, the method 500 may include controlling, by the TRU controller 216, the power supply from the axle generator 208 to the energy storage unit 204 based on the inputs received from the battery management controller 218. The inputs may indicate at least a charging rate and an amount of power to be supplied to the energy storage unit 204.

[0095] In one or more embodiments, the method 500 may include selecting, by the battery management controller 218, a reserve charging strategy if at least the SoC of the energy storage unit 204 is within a first predetermined range and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle 100. In the reserve charging strategy, the power supply from the axle generator 208 to the energy storage unit 204 may be limited.

[0096] In one or more embodiments, the method 500 may include selecting, by the battery management controller 218, an adaptive charging strategy if at least the SoC of the energy storage unit 204 is within the second predetermined range and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle 100. In the adaptive charging strategy, the power supplied from the axle generator 208 to the energy storage unit 204 may vary.

[0097] In one or more embodiments, the method 500 includes selecting, by the battery management controller 218, a critical charging strategy if at least the SoC of the energy storage unit 204 is within a third predetermined range and the speed condition indicates at least one of an acceleration condition and a coasting condition of the vehicle 100. In the critical charging strategy, maximum power may be supplied from the axle generator 208 to the energy storage unit 204.

[0098] In one or more embodiments, method 500 includes enabling, by battery management controller 218, power supply from axle generator 208 to energy storage unit 204 if at least the SoC of energy storage unit 204 is less than 100% and the speed condition indicates at least one of a braking condition and a deceleration condition.

[0099] Although shown and described in a particular order Figure 5 However, according to various embodiments of the present disclosure, the steps may appear in a variation of this order. In addition, for the sake of brevity, Figure 1-4 The relevant descriptions have already covered Figure 5 The details of each step will not be discussed in detail here.

[0100] As will be gathered, the present disclosure provides a power system 108 and a method 500 of supplying power to an energy storage unit 204 of the power system 108. As previously explained, the energy storage unit 204 can be charged using a power supply from the axle generator 208 based on the SoC of the energy storage unit 204 and the speed condition of the vehicle 100. In particular, a charging strategy is selected from a plurality of charging strategies based on the SoC of the energy storage unit 204 and the speed condition of the vehicle 100. Based on the charging strategy, the energy storage unit 204 is charged only when the SoC falls within the second and third predetermined ranges and if the vehicle 100 is moving. This significantly increases the utilization of the energy storage unit 204. In addition, such a charging strategy can eliminate the need to charge the energy storage unit 204 every time the SoC drops below 100%. The energy storage unit 204 is charged only when the SoC is below 100% when the vehicle 100 is in a deceleration or braking condition. This therefore minimizes the utilization of the axle generator 208 for charging the energy storage unit 204 and thereby results in a significant reduction in overall fuel consumption and fuel emissions.

[0101] Although specific language has been used to describe the subject matter, any limitation resulting therefrom is not intended. As will be apparent to those skilled in the art, various modifications in operation may be made to the method to realize the inventive concept as taught herein. The accompanying drawings and the foregoing description provide examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may be well combined into a single functional element. Alternatively, some elements may be divided into a plurality of functional elements. Elements from one embodiment may be added to another embodiment.

Claims

1. A power system for a vehicle having a transport refrigeration unit (TRU), the power system comprising: an energy storage unit adapted to supply power to the TRU; an axle generator in communication with the energy storage unit and adapted to supply power to at least one of the energy storage unit and the TRU; as well as a charging system in communication with the energy storage unit, the axle generator, and the TRU, wherein the charging system is configured to: monitoring a state of charge (SoC) of the energy storage unit; determining at least one operating characteristic associated with the vehicle, wherein the at least one operating characteristic is indicative of at least a speed condition of the vehicle; as well as Based on the monitored SoC and the determined operating characteristics, power supply from the axle generator to the energy storage unit is controlled.

2. The power system according to claim 1, wherein: The speed condition indicates at least one of an acceleration condition, a deceleration condition, a coasting condition, and a braking condition.

3. The power system according to claim 1, wherein: In order to control the power supply, the charging system is configured to: selecting a charging strategy from a plurality of charging strategies to charge the energy storage unit based on the monitored SoC and the determined operating characteristic; as well as Based on the selected charging strategy, the power supply from the axle generator to the energy storage unit is controlled.

4. The power system according to claim 3, wherein: The plurality of charging strategies include at least a reserve charging strategy, an adaptive charging strategy and a critical charging strategy.

5. A power system according to any one of the preceding claims, wherein: The charging system includes a battery management controller and a power management controller in communication with each other.

6. A power system according to any one of the preceding claims, wherein: In order to control the power supply from the axle generator to the energy storage unit based on the selected charging strategy, the charging system is configured to: generating, by the battery management controller, inputs associated with the selected charging strategy, wherein the inputs indicate at least a charging rate and an amount of power to be supplied to the energy storage unit; receiving, by the power management controller, the generated input from the battery management controller; as well as The supply of power from the axle generator to the energy storage unit is controlled by the power management controller based on input received from the battery management controller.

7. A power system according to any one of the preceding claims, wherein: The battery management controller is configured to select the reserve charging strategy if at least: The SoC of the energy storage unit is within a first predetermined range, and the speed condition indicates at least one of the acceleration condition and the coasting condition of the vehicle, Wherein, the power management controller is configured to limit the power supply from the axle generator to the energy storage unit if the reserve charging strategy is selected.

8. A power system according to any one of the preceding claims, wherein: The battery management controller is configured to select the adaptive charging strategy if at least: The SoC of the energy storage unit is within a second predetermined range, wherein the second predetermined range is lower than the first predetermined range, and The speed condition indicates at least one of the acceleration condition and the coasting condition of the vehicle.

9. A power system according to any one of the preceding claims, wherein: The power management controller is configured to variably supply the power from the axle generator to the energy storage unit if the adaptive charging strategy is selected, wherein the power management controller is configured to change the torque associated with the axle generator based on the SoC of the energy storage unit to supply variable power to the energy storage unit.

10. A power system according to any one of the preceding claims, wherein: The battery management controller is configured to select the critical charging strategy if at least: the SoC of the energy storage unit is within a third predetermined range, wherein the third predetermined range is lower than the second predetermined range, and the speed condition indicates at least one of the acceleration condition and the coasting condition of the vehicle, Wherein the power management controller is configured to allow maximum power supply from the axle generator to the energy storage unit if the critical charging strategy is selected.

11. A power system according to any one of the preceding claims, wherein: The battery management controller is configured to allow power supply from the axle generator to the energy storage unit if at least: The SoC of the energy storage unit is less than 100%, and The speed condition indicates at least one of the braking condition and the deceleration condition.

12. The power system according to claim 1, wherein: The energy storage unit includes at least one of a battery and a flow battery.

13. A method of controlling power supply to an energy storage unit of a vehicle having a transport refrigeration unit (TRU), the method comprising: monitoring a state of charge (SoC) of the energy storage unit; determining at least one operating characteristic associated with the vehicle, wherein the at least one operating characteristic is indicative of at least a speed condition of the vehicle; as well as Based on the monitored SoC and the determined operating characteristics, power supply from an axle generator of the vehicle to the energy storage unit is controlled to charge the energy storage unit.

14. The method according to claim 13, wherein: Controlling the power supply further comprises: selecting a charging strategy from a plurality of charging strategies to charge the energy storage unit based on the monitored SoC and the determined operating characteristic; and Based on the selected charging strategy, the power supply from the axle generator to the energy storage unit is controlled.

15. The method according to any one of claims 13 and 14, wherein: The speed condition indicates at least one of an acceleration condition, a deceleration condition, a coasting condition, and a braking condition; and The plurality of charging strategies include at least a reserve charging strategy, an adaptive charging strategy and a critical charging strategy.

16. The method according to any one of claims 14-15, wherein: Based on the selected charging strategy, controlling the power supply from the axle generator to the energy storage unit further comprises: generating, by a battery management controller, inputs associated with the selected charging strategy, wherein the inputs indicate at least a charging rate and an amount of power to be supplied to the energy storage unit; receiving, by a power management controller, the generated input from the battery management controller; and The supply of power from the axle generator to the energy storage unit is controlled by the power management controller based on input received from the battery management controller.

17. The method according to any one of claims 14 to 16, further comprising: The reserve charging strategy is selected by the battery management controller if at least: The SoC of the energy storage unit is within a first predetermined range, and the speed condition indicates at least one of the acceleration condition and the coasting condition of the vehicle, In the reserve charging strategy, the power supply is limited to from the axle generator to the energy storage unit.

18. The method according to any one of claims 14 to 17, further comprising: The adaptive charging strategy is selected by the battery management controller if at least: The SoC of the energy storage unit is within a second predetermined range, wherein the second predetermined range is lower than the first predetermined range, and the speed condition indicates at least one of the acceleration condition and the coasting condition of the vehicle, Therein, in the adaptive charging strategy, the power supplied from the axle generator to the energy storage unit is varied.

19. The method according to any one of claims 14 to 18, further comprising: The critical charging strategy is selected by the battery management controller if at least: the SoC of the energy storage unit is within a third predetermined range, wherein the third predetermined range is lower than the second predetermined range, and the speed condition indicates at least one of the acceleration condition and the coasting condition of the vehicle, Therein, in the critical charging strategy, maximum power is supplied from the axle generator to the energy storage unit.

20. The method according to any one of claims 14 to 19, further comprising: The supply of power from the axle generator to the energy storage unit is permitted by the battery management controller if at least: The SoC of the energy storage unit is less than 100%, and The speed condition indicates at least one of the braking condition and the deceleration condition.

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