Intelligent charging connector for transport refrigeration systems

Abstract

A transport refrigeration system includes a transport refrigeration unit including a compressor, a controller, and one or more valves; an energy storage device configured to provide electrical power to the transport refrigeration unit; and a smart charge connector in electrical communication with the energy storage device and / or the transport refrigeration unit, the smart charge connector connectable to an electrical grid and configured to selectively control the provision of electrical power from the energy storage device and / or the electrical grid to the transport refrigeration unit by transitioning the provision of electrical power to the transport refrigeration unit from being supplied by the energy storage device or the electrical grid in response to the smart charge connector being connected to the electrical grid or disengaging from the electrical grid, respectively.

Description

Background Technology

[0001] The embodiments described herein generally relate to transport refrigeration systems, and more specifically to energy management of such transport refrigeration systems.

[0002] Typically, cold chain distribution systems are used to transport and distribute goods that may be susceptible to temperature, humidity, and other environmental factors, or more specifically, perishable 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, and pharmaceuticals. Advantageously, cold chain distribution systems allow for the efficient transport and distribution of perishable goods without damage or other undesirable effects.

[0003] Refrigerated vehicles and trailers are commonly used in cold chain distribution systems to transport perishable goods. The transport refrigeration system is operatively mounted to the vehicle or trailer in connection with the cargo space defined within it, in order to maintain a controlled temperature environment within the cargo space.

[0004] Typically, transport refrigeration systems used in conjunction with refrigerated vehicles and trailers include a transport refrigeration unit with a refrigerant compressor, a condenser with one or more associated condenser fans, an expansion unit, and an evaporator with one or more associated evaporator fans, connected via appropriate refrigerant lines in a closed refrigerant flow loop. Air or an air / gas mixture is drawn from the interior volume of the cargo space by means of the evaporator(s) associated with the evaporator, passing through the airside of the evaporator in heat exchange with the refrigerant. The refrigerant absorbs heat from the air, thereby cooling it. The cooled air is then supplied back to the cargo space.

[0005] Regarding commercially available transport refrigeration systems used in conjunction with refrigerated vehicles and trailers, the compressor and other components of the transport refrigeration unit typically must be powered during transit by a prime mover. In mechanically driven transport refrigeration systems, the compressor is driven by the prime mover via direct mechanical coupling or belt drive, and other components such as the condenser and evaporator fan are belt-driven.

[0006] Transportation refrigeration systems can also be electrically driven. In an electrically driven transportation refrigeration system, components of the transportation refrigeration unit (such as the compressor) are powered by current supplied by the battery during "road mode" and by the power grid during "standby mode." "Road mode" refers to an operating mode in which the transportation refrigeration system is not connected to the power grid, such as when the refrigerated vehicle is in transit. "Standby mode" refers to an operating mode in which the transportation refrigeration system is connected to the power grid, such as when the refrigerated vehicle is parked and plugged into a charging station. Maintaining uninterrupted compressor operation during transitions from one mode to another is ideal; however, typically, when transitioning from road mode to standby mode, a large inrush current may occur if the compressor motor does not stop due to the voltage and phase difference between the grid and motor terminal voltage. Similarly, when transitioning from standby mode to road mode using conventional methods, a power interruption may occur when disconnecting the charging connection from the grid due to the current supplied by the grid. To avoid these problems, a method is expected to smoothly transfer between these two modes to allow for uninterrupted operation of the compressor. Summary of the Invention

[0007] According to one embodiment, a transportation refrigeration system is provided. The transportation refrigeration system includes: a transportation refrigeration unit including a compressor, a controller, and one or more valves; an energy storage device configured to provide electrical power to the transportation refrigeration unit; and a smart charging connector electrically communicating with the energy storage device and / or the transportation refrigeration unit, the smart charging connector being connectable to a power grid and configured to selectively control the supply of electrical power from the energy storage device and / or the power grid to the transportation refrigeration unit, wherein the smart charging connector is configured to, in response to connection to the power grid, transition the supply of electrical power to the transportation refrigeration unit from being supplied by the energy storage device to being supplied by the power grid, and wherein the smart charging connector is configured to, in conjunction with disconnection from the power grid, transition the supply of electrical power to the transportation refrigeration unit from being supplied by the power grid to being supplied by the energy storage device.

[0008] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: a power conversion unit configured to convert the amplitude, frequency, and phase of the electrical power signal provided by the energy storage device and / or the power grid.

[0009] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: the smart charging connector comprising: a switch configured to, when the switch is closed, directly connect the transport refrigeration unit to the power grid; a grid voltage detection unit configured to detect characteristics of an electrical power signal supplied by the power grid, wherein the characteristics include the amplitude, phase, and frequency of the electrical power signal supplied by the power grid; and a communication unit configured to communicate with the power conversion unit to transmit and receive characteristics of electronic power signals being supplied by the power grid and / or the energy storage device.

[0010] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: the smart charging connector being configured to, in response to the smart charging connector being connected to the power grid, transmit the characteristics of the electrical power signal supplied by the power grid to the power conversion unit, and the power conversion unit being configured to, based on the characteristics of the electrical power signal supplied by the power grid, gradually convert the characteristics of the electrical power signal supplied from the energy storage device to the transport refrigeration unit to match the characteristics of the electrical power signal supplied by the power grid.

[0011] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: the characteristics of the electrical power signal supplied from the energy storage device include the amplitude, frequency, and phase of the electrical power signal supplied from the energy storage device.

[0012] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: the power conversion unit being configured to gradually convert the characteristics of the electrical power signal supplied from the energy storage device to the transport refrigeration unit in consideration of the rate of change of the continuous operation of the transport refrigeration unit.

[0013] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: the smart charging connector being configured to close the switch in response to communication received from the power conversion unit indicating that the characteristics of the electrical power signal supplied from the energy storage device have been converted to match the characteristics of the electrical power signal supplied by the power grid, so that the power grid is directly connected to the transport refrigeration unit.

[0014] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may further include: the power conversion unit being configured to close the switch in response to supplying the power signal to the energy storage device by converting the characteristics of the power signal supplied from the power grid into characteristics matching the power signal required to charge the energy storage device.

[0015] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may further include: the power conversion unit being configured to, in response to receiving a signal instructing a user to disconnect the smart charging connector from the power source, replace the electrical power signal supplied from the power grid to the transport refrigeration unit with an electrical power signal supplied by the energy storage device that has been converted by the power conversion unit to have characteristics matching those of the electrical power signal supplied by the power grid.

[0016] In addition to one or more of the features described above, or as an alternative, another embodiment of the transport refrigeration system may include: the smart charging connector being configured to, in response to an indication received from the power conversion unit that the transport refrigeration unit is powered entirely by the energy storage device, cause the switch to open and an indication that the smart charging connector is ready to disconnect from the power source is displayed for user observation.

[0017] According to another embodiment, a method is provided for transitioning a transport refrigeration system from road mode to standby mode. The method includes: connecting a smart charging connector to a power grid supplying grid power; detecting the electrical characteristics of the grid power by the smart charging connector; transmitting the electrical characteristics of the grid power to a power conversion unit; adjusting the electrical characteristics of power supplied from a battery to a compressor by the power conversion unit to match the electrical characteristics of the grid power; closing a switch by the smart charging connector, wherein the closed switch provides a direct connection between the grid power and the compressor; and turning off the power conversion unit to prevent power flow from the battery to the compressor.

[0018] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from road mode to standby mode may further include: the power supplied to the compressor is supplied from the battery to the compressor via the power conversion unit.

[0019] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from road mode to standby mode may further include: adjusting the electrical characteristics of the power supplied to the compressor to match the electrical characteristics of the grid power, including: gradually adjusting the electrical characteristics of the power supplied to the compressor; and repeatedly checking the electrical characteristics of the power supplied to the compressor until a match with the electrical characteristics of the grid power has been achieved.

[0020] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from road mode to standby mode may further include: adjusting the electrical characteristics of the power supplied to the compressor, including changing one or more of the amplitude, phase, or frequency of the power supplied to the compressor.

[0021] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from road mode to standby mode may further include: activating the power conversion unit to convert the grid power into DC power suitable for charging the battery.

[0022] According to another embodiment, a method is provided for transitioning a transport refrigeration system from a standby mode to a road mode. The method includes: operating the transport refrigeration system in the standby mode, wherein the standby mode includes powering the compressor of the transport refrigeration system with grid power via a direct connection from the compressor to the power grid; receiving an indication that the standby mode should end via a smart charging connector; activating a power conversion unit that receives power supplied by a battery as input and supplies output power to the compressor; gradually adjusting the electrical characteristics of the output power supplied to the compressor by the power conversion unit to match the electrical characteristics of the grid power; and, in response to determining that the power supplied to the compressor from the power conversion unit has completely replaced the power supplied to the compressor from the power grid, disconnecting a switch by the smart charging connector to disengage the direct connection from the compressor to the power grid.

[0023] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from standby mode to road mode may further include: determining that the power supplied from the power conversion unit to the compressor has completely replaced the power supplied from the power grid to the compressor includes: the power conversion unit determining that the power supplied from the power conversion unit to the compressor has completely replaced the power supplied from the power grid to the compressor; and transmitting an indication from the power conversion unit that the power supplied from the power conversion unit to the compressor has completely replaced the power supplied from the power grid to the compressor to the smart charging connector.

[0024] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from standby mode to road mode may further include: the electrical characteristics of the output power supplied to the compressor include one or more of the amplitude, phase, and frequency of the output power.

[0025] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from standby mode to road mode may further include: operating the transport refrigeration system in the standby mode includes using the grid power to charge the battery.

[0026] In addition to one or more of the features described above, or as an alternative, another embodiment of the method for transitioning a transport refrigeration system from standby mode to road mode may include: receiving an indication from a smart charging connector that the standby mode should end, including: determining by a sensor associated with the battery that the battery has been fully charged; and turning off the power conversion unit.

[0027] The technical effects of embodiments of this disclosure include allowing a smooth transition between different operating modes by preventing large inrush currents that could otherwise cause the transport refrigeration system to be connected to the power grid and power interruptions caused by disconnection from the power grid. This smooth transition allows for continuous, uninterrupted operation of the transport refrigeration system.

[0028] Unless otherwise expressly indicated, the foregoing features and elements can be combined in various combinations non-exclusively. These features and elements, and their operation, will become more apparent from the following description and drawings. However, it should be understood that the following description and drawings are intended to be illustrative and interpretative in nature, rather than limiting. Attached Figure Description

[0029] The following description should not be considered limiting in any way. Referring to the accompanying drawings, similar elements are similarly numbered: Figure 1 This is a schematic diagram of a transport refrigeration system according to an embodiment of the present disclosure; Figure 2A Based on embodiments of this disclosure and Figure 1 A block diagram of an integrated smart charging connector for a transport refrigeration system; Figure 2B This is a block diagram of a smart charging connector integrated with a transport refrigeration system operating in road mode, according to an embodiment of the present disclosure. Figure 2C This is a block diagram of a smart charging connector integrated with a transport refrigeration system operating in standby mode, according to an embodiment of the present disclosure. Figure 3 The illustration shows the use of embodiments according to this disclosure. Figure 2A The process of transitioning a transport refrigeration system from road mode to standby mode; and Figure 4 The illustration shows the use of embodiments according to this disclosure. Figure 2A The process of transitioning a transport refrigeration system from standby mode to road mode. Detailed Implementation

[0030] Detailed descriptions of one or more embodiments of the disclosed apparatus and methods are presented herein by way of illustration rather than limitation, with reference to the figures.

[0031] refer to Figure 1 and Figure 2A-2C The illustrations show various embodiments disclosed herein. Figure 1 A schematic diagram of a transport refrigeration system 200 according to an embodiment of the present disclosure is shown. Figure 2A The embodiments shown are related to this disclosure. Figure 1 Block diagram of the integrated smart charging connector 28 of the transport refrigeration system 200. Figure 2B and Figure 2C Block diagrams of the transport refrigeration system 200 operating in road mode and in standby mode are shown respectively.

[0032] like Figure 1As seen in the diagram, the transport refrigeration system 200 is illustrated as a trailer system 100. The trailer system 100 includes a vehicle 102 integrally connected to a transport container 106. The vehicle 102 includes an operator's compartment or cab 104 and a propulsion motor 120, which acts as the drive system for the trailer system 100. The propulsion motor 120 is configured to power the vehicle 102. The energy source powering the propulsion motor 120 can be at least one of the following: compressed natural gas, liquefied natural gas, gasoline, electricity, diesel, or a combination thereof. The propulsion motor 120 can be an electric motor or a hybrid motor (e.g., an internal combustion engine and an electric motor). The transport container 106 is coupled to the vehicle 102. The transport container 106 may be removably coupled to the vehicle 102. The transport container 106 is a refrigerated trailer and includes a top wall 108, an opposing bottom wall 110, opposing side walls 112, and a front wall 114, wherein the front wall 114 is closest to the vehicle 102. The transport container 106 also includes one or more doors 117 located at a rear wall 116 opposite the front wall 114. The walls of the transport container 106 define refrigerated cargo space 119. Those skilled in the art will recognize that the embodiments described herein are applicable to tractor-trailer refrigeration systems or non-trailer refrigeration systems, such as, for example, rigid trucks and trucks with refrigerated compartments.

[0033] Typically, the transport refrigeration system 200 is used to transport and distribute perishable goods and environmentally sensitive goods (referred to herein as perishable goods 118). Perishable goods 118 may include, but are not limited to, fruits, vegetables, grains, beans, nuts, eggs, dairy products, seeds, flowers, meat, poultry, fish, ice, blood, pharmaceuticals, or any other suitable goods requiring temperature-controlled transport. The transport refrigeration system 200 includes a transport refrigeration unit 22, an energy storage device 24, a power conversion unit 26, and a smart charging connector 28. The transport refrigeration unit 22 includes a refrigerant compressor 32 for providing heat transfer functionality and an electric motor (not shown) for driving the refrigerant compressor 32. The transport refrigeration unit 22 is operatively associated with a refrigerated cargo space 119 and is configured to supply conditioned air to the transport container 106. The transport refrigeration unit 22 operates under the control of a controller (not shown) to establish and regulate desired environmental parameters, such as, for example, temperature, pressure, humidity, carbon dioxide, ethylene, ozone, light exposure, vibration exposure, and other conditions in the cargo space 119 as known to those skilled in the art. In an embodiment, the transport refrigeration unit 22 is capable of providing a desired temperature and humidity range.

[0034] Airflow is circulated into and through the refrigerated cargo space 119 of the transport container 106 via the transport refrigeration unit 22. According to some embodiments, the transport refrigeration unit 22 may include a refrigerant compressor 32 (which may be simply referred to as compressor 32), a refrigerant heat exchanger, an expansion device, and a refrigerant heat exchanger, these devices being connected in refrigerant flow communication in a closed-loop refrigerant circuit and arranged in a conventional refrigeration cycle. The refrigerant compressor 32 may be a single-stage or multi-stage compressor, such as, for example, a reciprocating compressor or a scroll compressor. The transport refrigeration unit 22 may also include one or more fans associated with the refrigerant heat exchanger and capable of being driven by one or more fan motors, and one or more fans associated with the refrigerant heat exchanger and driven by one or more fan motors. The transport refrigeration unit 22 may also include a heater associated with the refrigerant heat exchanger. It should be understood that other components may be incorporated into the refrigerant circuit as desired, including, but not limited to, a suction modulation valve, a receiver, a filter / dryer, and an economizer circuit. Those skilled in the art will understand the conventional components and functionality of the loop airflow provided by the refrigeration unit 22 to the refrigerated cargo space 119, and accordingly, they will not be shown or described in detail herein. It will be understood that... Figure 2A The compressor 32 shown can be a component of the refrigeration unit 22.

[0035] The transport refrigeration unit 22 can be powered by an energy storage device 24 (which, for simplicity, may be referred to as battery 24), which provides electrical power to the transport refrigeration unit 22 during operation of the transport refrigeration system in road mode. Examples of the energy storage device 24 may include a battery system (e.g., a battery or battery pack), a fuel cell, a flow battery, and other devices capable of storing and outputting electrical energy that can be direct current (DC). The energy storage device 24 may include a battery system that can employ multiple batteries organized into a battery pack.

[0036] Battery 24 can be charged via a fixed charging station 30 (such as, for example, a wall-mounted 48V power outlet or another outlet connected to the power grid 30). Charging station 30 can provide single-phase (e.g., Level 2 charging capacity) or three-phase AC power to energy storage device 24. It is understood that charging station 30 can have any phase for charging, and the embodiments disclosed herein are not limited to single-phase or three-phase AC power. In embodiments, single-phase AC power can be high-voltage DC power, such as, for example, 500VDC.

[0037] In one embodiment, such as Figure 1As shown, the energy storage device 24 is located outside the transport refrigeration unit 22. In another embodiment, the energy storage device 24 is located inside the transport refrigeration unit 22. The transport refrigeration unit 22 can have multiple power-demanding loads connected to the energy storage device 24, including but not limited to a motor for the compressor 32, a drive motor for a fan associated with a refrigerant heat exchanger, a drive motor for a fan associated with a refrigerant heat absorption exchanger, or any other aspect of the transport refrigeration unit 22 that may require power.

[0038] The motor used to power the refrigerant compressor 32 is typically an alternating current (AC) motor. However, the power supplied by the battery 24 is DC voltage. Therefore, a power conversion unit 26 is electrically connected between the battery 24 and the refrigerant compressor 32 to convert the power supplied from the battery 24 to the refrigerant compressor 32 from DC to AC. According to some embodiments, such as... Figure 2A As shown, the power conversion unit 26 may include a first filter 262 connected to a first converter 264, the first converter 264 connected to a second converter 266, and the second converter 266 connected to a second filter 268. According to some embodiments, either or both of filters 262 and 268 may be filters of the same or different types (e.g., L, LC, LCL, etc.) configured to reduce harmonics of electrical power. In various embodiments, the first converter 264 and / or the second converter 266 may be an AC-to-DC rectifier, a DC-to-AC inverter, an AC-to-AC voltage / frequency converter, and / or a DC-to-DC voltage converter. In some embodiments, the first converter 264 may be a DC-to-DC converter, and the second converter 266 may be a DC-to-AC inverter. According to some embodiments, the first converter 264 may be configured to convert an input DC signal (e.g., an input from battery 24) into an output DC signal of a different voltage (e.g., to the output of the second converter 266). In some embodiments, the second converter 266 can be configured to convert an input DC signal (e.g., an input from the first converter 264) into an output AC signal (e.g., an output to the refrigerant compressor 32). Figure 2B As shown, when the transport refrigeration system 200 is in road mode, an electrical power signal flows from the battery 24 through the power conversion unit 26, which converts the DC power supplied by the battery 24 into appropriate AC power for use by the refrigerant compressor 32.

[0039] like Figure 2C As shown, Figure 2CThe diagram describes the power flow of the transport refrigeration system 200 when it is in standby mode. The power conversion unit 26 is also electrically connected to the smart charging connector 28, allowing the AC power supplied by the power grid 30 to be converted into DC power by the power conversion unit 26 to charge the battery 24. Therefore, it should be understood that the power conversion unit 26 can also operate in reverse, enabling the second converter 266 to convert the AC power supplied by the power grid 30 into DC power output to the first converter 264, and the first converter 264 to receive DC power and output another DC power at a different voltage suitable for charging the battery 24. Furthermore, when in standby mode, as... Figure 2C As shown, the power grid 30 can directly power the compressor 32 via the smart charging connector 28.

[0040] The power conversion unit 26 can be configured to alter one or more electrical characteristics of an input power signal and output a modified signal with the modified characteristics. As those skilled in the art will understand, the power conversion unit 26 can modify one or more of the amplitude, frequency, and / or phase of the signal so that, for example, the power signal output by the battery 24 can be altered to have electrical characteristics suitable for powering the compressor 32. According to some embodiments, the power conversion unit 26 includes a circuitry that enables the power conversion unit 26 to communicate with the smart charging connector 28.

[0041] like Figure 2A-2CAs shown, in some embodiments, when the smart charging connector 28 is connected to the power grid 30 (e.g., via a power cable inserted into the transport refrigeration system 200 in the charging station 30), the smart charging connector 28 is able to receive an input power signal from the power grid 30, and the smart charging connector 28 can output the signal to the power conversion unit 26 and / or to the compressor 32. The smart charging connector 28 includes a grid voltage detection unit 282, a communication unit 284, and a switch 286. The grid voltage detection unit 282 is configured to detect the electrical characteristics (e.g., phase, amplitude, and / or frequency) of the power signal output from the power grid 30 to the smart charging connector 28. The communication unit 284 is configured to transmit information (such as the electrical characteristics of the power signal from the power grid 30 and whether the switch 286 is closed) from the smart charging connector 28 to the power conversion unit 26. Switch 286 is positioned between smart charging connector 28 and compressor 32, such that when the switch is closed, the power signal supplied from power grid 30 is directly connected to compressor 32, and when the switch is open, there is no direct connection between compressor 32 and power grid 30, but power supplied from power grid 30 is input to power conversion unit 26. As will be explained in more detail below, smart charging connector 28 can supply information about the power supplied by power grid 30 (“grid power”) to power conversion unit 26, allowing power conversion unit 26 to convert the characteristics of the power supplied to compressor 32 to match the characteristics of grid power and to allow for a smooth transition between road mode and standby mode by selectively opening and closing switch 286. According to some embodiments, switch 286 can be a fast switch, which can include one or more semiconductor-based switches, mechanical switches, gas-based switches, or a combination or mixture of switch types. According to some embodiments, the switching time of the fast switch can be less than 1 microsecond. When transitioning from road mode to standby mode, the power conversion unit 26 can gradually change the electrical characteristics of the power supplied by the battery 24 and output to the compressor 32 to match the electrical characteristics of the power supplied by the power grid 30. After this gradual transition is complete, the power conversion unit 26 communicates with the smart charging connector 28 so that the smart charging connector 28 knows that the power supplied to the compressor 32 originating from the battery 24 now matches the characteristics of the power supplied from the power grid 30. At this time, the smart charging connector can close a switch, which provides a direct connection between the power grid 30 and the compressor 32 (i.e., entering standby mode). In this way, the compressor 32 can switch from battery power to grid power without experiencing current interruption surges. Once the system is in standby mode, as... Figure 2C As shown, the power conversion unit 26 is able to convert the power supplied from the power grid 30 into DC power for charging the battery 24.

[0042] According to some embodiments, the smart charging connector 28 may include an electronic controller comprising a processor and associated memory, the memory including computer-executable instructions that, when executed by the processor, cause the processor to perform various operations. The processor may be, but is not limited to, a single-processor or multi-processor system of a wide variety of possible architectures, including homogeneously or heterogeneously arranged field-programmable gate arrays (FPGAs), central processing units (CPUs), application-specific integrated circuits (ASICs), digital signal processors (DSPs), or graphics processing units (GPUs). The memory may be a storage device, such as, for example, random access memory (RAM), read-only memory (ROM), or other electronic, optical, magnetic, or any other computer-readable medium.

[0043] Now for reference Figure 3 Continue to refer to Figure 1 and Figure 2B . Figure 3 The illustration shows a flow chart of a method 300 for transitioning a transport refrigeration system 200 from road mode to standby mode according to an embodiment of the present disclosure.

[0044] In box 302, the transport refrigeration system 200 begins operation from the road mode. For example, vehicle 102 may be in transit. As described above, in this mode, compressor 32 is powered by battery 24.

[0045] At block 304, the method includes inserting the smart charging connector 28 into a power source. For example, an operator of vehicle 102 may park the vehicle and insert an electrical cable electrically connected to the smart charging connector 28 into a suitable port on the charging station 30.

[0046] In block 306, the method includes detecting the electrical characteristics of the power supplied by the power grid 30. For example, the grid voltage detection unit 282 of the smart charging connector 28 can detect the phase, amplitude, and frequency of the power supplied by the power grid 30.

[0047] At block 308, the method includes transmitting detected electrical characteristics of the power supplied by the power grid 30 to the power conversion unit 26, and specifically to the second converter 266. For example, the communication unit 284 of the smart charging connector 28 may transmit the detected electrical characteristics to the power conversion unit 26. Thus, according to some embodiments, the smart charging connector 28 is configured to transmit characteristics of the electrical power signal supplied by the power grid 30 to the power conversion unit 26 in response to a cable connection to the power grid 30.

[0048] At block 310, the method includes gradually adjusting the electrical characteristics (i.e., amplitude, phase, and / or frequency) of the power supplied from battery 24 to compressor 32 (via power conversion unit 26) to match the electrical characteristics of grid power. According to some embodiments, power conversion unit 26 is configured to gradually convert the characteristics of the power signal supplied from battery 24 to compressor 32 to match the characteristics of the power signal supplied from the power grid. In some embodiments, power conversion unit 26 is configured to gradually convert the characteristics of the power signal supplied from battery 24 to compressor 32 at a rate that takes into account the rate of change of continuous (i.e., uninterrupted) operation of compressor 32.

[0049] In block 312, the method includes determining whether the characteristics of the motor voltage (i.e., the power supplied from the power conversion unit 26 to the compressor 32) match the electrical characteristics of the grid power. If they still do not match, the method includes repeatedly checking until they match. Once the motor voltage characteristics match the grid power characteristics, the method proceeds to block 314.

[0050] In block 314, the method includes closing switch 286 by smart charging connector 28 to provide a direct connection between power grid 30 and compressor 32. According to some embodiments, smart charging connector 28 is capable of closing switch 286 in response to communication received from power conversion unit 26 indicating that the characteristics of an electrical power signal supplied from battery 24 have been converted to match the characteristics of an electrical power signal supplied by power grid 30.

[0051] In block 316, the method includes shutting off the power conversion unit 26 to prevent the flow of electrical power from the battery 24 to the compressor 32 by, for example, turning off the pulse width modulation (PWM) of the first converter 264 (i.e., terminating the operation of the first converter 264) and turning off the pulse width modulation (PWM) of the second converter 266. At this point, the power supplied by the power grid 30 will seamlessly replace the power previously supplied by the battery 24 (via the power conversion unit 26), and the compressor 32 will be fully powered by grid power without experiencing any interruption to its operation.

[0052] At block 318, the method includes activating power conversion unit 26 (i.e., first converter 264 and second converter 266) to convert power supplied by power grid 30 into DC power suitable for charging battery 24. For example, in some embodiments, power conversion unit 26 may convert 480V / 60Hz grid power into 500V DC power. It will be understood that, according to various embodiments, the voltage and / or frequency of the electrical power received and / or output by power conversion unit 26 may vary based on the characteristics of grid power and the operational needs of battery 24 and / or compressor 32.

[0053] At block 320, the method includes operating in a standby mode. In some embodiments, operating in standby mode includes: the compressor 32 being powered entirely by grid power, and the battery 24 being charged by grid power (i.e., via power conversion unit 26). According to some embodiments, when in standby mode, a second converter 266 may regulate the DC link voltage and current to convert grid power from AC to DC, and a first converter 264 may regulate the voltage and current supplied to the battery 24 to charge the battery 24.

[0054] Now for reference Figure 4 Continue to refer to Figure 1 and Figure 2C . Figure 4 The illustration shows a flow chart of a method 400 for transitioning a transport refrigeration system 200 from standby mode to road mode according to an embodiment of the present disclosure.

[0055] In box 402, the transport refrigeration system 200 begins operation from standby mode. For example, vehicle 102 can be parked and plugged into charging station 30. As described above, in this mode, compressor 32 is powered by power grid 30, and power grid 30 can also be used to charge battery 24.

[0056] At block 404, the method optionally includes determining whether battery 24 is fully charged. According to some embodiments, if battery 24 is not fully charged, the method includes continuing to charge battery 24 until battery 24 is fully charged.

[0057] At block 406, the method includes stopping charging of battery 24. According to some embodiments, battery 24 may include sensors for determining the amount of charge in battery 24 and whether battery 24 is fully charged. In some embodiments, battery 24 is paired with a communication unit communicating with smart charging connector 28 to provide the charging status of battery 24. Upon receiving notification that battery 24 is fully charged, smart charging connector 28 may terminate further charging of battery 24. Furthermore, at block 406, the method includes turning off power conversion unit 26 to prevent electrical power flow from power grid 30 to battery 24. For example, pulse width modulation (PWM) of first converter 264 and second converter 266 can be turned off in response to a command from smart charging connector 28. PWM can be a pattern of signals used to turn power semiconductor devices located inside power conversion unit 26 on / off, such that when the PWM to the converter is shut off, the converter will terminate operation.

[0058] At block 408, the method includes determining whether an indication that the standby mode should end has been provided. If not, the method continues to perform a check to determine whether an indication that the standby mode should end has been provided. According to some embodiments, the indication that the standby mode should end may be provided as user input. For example, if the operator of vehicle 102 has determined that the vehicle needs to proceed with transport, the operator may, for example, press a button on the control panel of vehicle 102 to provide the smart charging connector 28 with an indication that it should initiate a transition from standby mode to road mode (i.e., begin the transition of the compressor 32 from grid power to battery power). According to some embodiments, such as in the case where vehicle 102 is an autonomous or self-driving vehicle that can be configured to automatically connect the smart charging connector 28 to the power grid 30 and is also configured to automatically disconnect the smart charging connector 28 from the power grid 30, the indication that the standby mode should end may be provided by the control system of vehicle 102 in response to, for example, a determination by the control system that the vehicle will initiate transport in the near future. If the indication that the standby mode should end has been received, the method proceeds to block 410.

[0059] In block 410, the method includes turning on the power conversion unit 26 to begin supplying power from the battery 24 to the compressor 32. A first converter 264 is capable of regulating the DC voltage supplied from the battery 24, and a second converter 266 is capable of regulating the current by converting the DC voltage into an AC voltage supplied to the compressor 32. In this state, the power conversion unit 26 can be considered to be in a current control mode where, in addition to the current supplied by the power grid 30, the second converter 266 is allowed to supply current to the compressor 32. During this state, the terminal voltage of the compressor 32 is determined by the power grid 30. The power conversion unit 26 can be configured to output a power signal to the compressor 32 that gradually increases in electrical characteristics and has electrical characteristics matching those of the grid power supplied to the compressor 32, such that power supplied by the battery 24 (via the power conversion unit 26) can be supplied to the compressor 32 to replace the power supplied by the power grid 30. In other words, in block 410, the second converter 266 is able to regulate the current supplied from battery 24 to compressor 32 such that the current matches the phase and frequency of the current supplied from power grid 30 to compressor 32, but the second converter 266 is able to gradually increase the amplitude of the current supplied from battery 24 to replace the current supplied by power grid 30.

[0060] At block 412, the method involves reducing the current supplied to the power grid of the compressor 32 to zero. As those skilled in the art will understand, when the power conversion unit 26 is activated, the compressor 32 receives power from both the power grid 30 and the battery 24 (i.e., via the power conversion unit 26). However, as the power supplied from the battery 24 to the compressor 32 via the power conversion unit 26 (i.e., the output current of the second converter 266) gradually increases, this power will naturally displace the power supplied to the compressor 32 from the power grid 30 until no power from the power grid 30 is powering the compressor 32.

[0061] At block 414, the method includes operating compressor 32 using power supplied from battery 24 via power conversion unit 26. In some embodiments, second converter 266 is capable of switching from current control mode to motor control mode based on the electrical characteristics of the power supplied by power grid 30. As previously explained, smart charging connector 28 is capable of transmitting (e.g., via communication unit 284) the electrical characteristics of grid power to power conversion unit 26, and then the power conversion unit is capable of using this information to convert the power supplied by battery 24 into power with characteristics matching those of grid power, such that the battery-supplied power can replace grid power at compressor 32 without any interruption. During motor control mode, the ultimate goal is to control the speed of the motor of compressor 32 in an appropriate manner. According to some embodiments, during motor control mode, the motor terminal voltage of compressor 32 will depend on the operating point of the system, and the reference setting for motor control will be speed and flux, rather than current. The second converter 266 can use the grid power characteristics to transition from current control mode to motor control mode without any interruption to the operation of compressor 32, by converting the grid power characteristics into a reference for motor control. During motor control mode, compressor 32 is powered entirely by electrical power supplied by battery 24 (via power conversion unit 26).

[0062] In box 416, the smart charging connector 28 can disconnect switch 286, thereby severing the direct connection between the power grid 30 and the compressor 32. This will not affect the compressor 32 because, up to this point, the compressor 32 is being powered entirely by power supplied by the battery, which is converted by the power conversion unit 26 to match the characteristics of grid power. According to some embodiments, the smart charging connector 28 can disconnect switch 286 in response to receiving communication from the power conversion unit 26 that the compressor 32 is being powered entirely by power output from the power conversion unit 26 (i.e., originating from battery 24). According to some embodiments, the smart charging connector 28 is configured to disconnect switch 286 in response to an indication received from the power conversion unit 26 that the compressor 32 is being powered entirely by electrical power supplied by battery 24, and an indication that the cable is ready to be disconnected from the power source is displayed for user observation.

[0063] At box 418, the method includes detaching the cable from the charging station / power grid 30. According to some embodiments, the cable can be manually disconnected by an operator of the vehicle 102. In some embodiments, the vehicle can provide an indication that the cable is ready for disconnection, such as a notification light or sound. According to some embodiments, the smart charging connector 28 is capable of making such a notification in response to receiving communication from the power conversion unit 26 that the compressor 32 is being fully powered by the battery 24.

[0064] In block 420, the method includes operating the transport refrigeration system in road mode by means of a power conversion unit 26 to regulate the power supplied to the compressor 32. For example, a first converter 264 can regulate the DC voltage link, and a second converter 266 can control the motor of the compressor 32. According to some embodiments, after the cable is disconnected from the power grid 30, the power conversion unit 26 can gradually adjust the electrical characteristics of the power supplied to the compressor 32 so that the electrical characteristics are consistent with a predetermined set of road mode electrical characteristics. In this way, after disconnection from the grid power, the battery 24 can smoothly replace the grid power as the power source to the compressor 32, and then the power supplied to the compressor 32 can be gradually adjusted to restore the desired road mode characteristics (i.e., the desired amplitude, phase, and frequency). In this way, the smart charging connector 28 can smoothly (i.e., in the event of interruption of continuous operation of the transport refrigeration unit 22) transition the supply of electrical power to the compressor 32 of the transport refrigeration unit 22 from being supplied by the battery 24 to being supplied by the power grid 30.

[0065] Although the above descriptions have been presented in a specific order Figure 3 and Figure 4 The process is as described, but it should be recognized that the order of steps may vary unless otherwise specifically required in the appended claims.

[0066] As described above, embodiments can take the form of processes implemented by a processor and means (such as a processor) for practicing those processes. Embodiments can also take the form of computer program code containing instructions embodied in a tangible medium (such as a floppy disk, CD-ROM, hard disk, or any other computer-readable storage medium), wherein when the computer program code is loaded into and executed by the computer, the computer becomes means for practicing the embodiments. Embodiments can also take the form of, for example, computer program code stored in a storage medium, loaded into and / or executed by the computer, computer program code transmitted through a transmission medium, or computer program code transmitted through a transmission medium (such as via wires or cables, via optical fibers, or via electromagnetic radiation); wherein when the computer program code is loaded into and executed by the computer, the computer becomes means for practicing the exemplary embodiments. When implemented on a general-purpose microprocessor, computer program code segments configure the microprocessor to create specific logic circuits.

[0067] The term “approximately” is intended to include the degree of error associated with a measurement based on a specific quantity of equipment available at the time of application submission. For example, “approximately” may include a range of ±8%, 5%, or 2% of a given value.

[0068] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a / an” and “the” are intended to include the plural forms as well. It will also be further understood that the terms “comprise and / or comprising” as used in this specification specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0069] Although this disclosure has been described with reference to one or more exemplary embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereunder without departing from the scope of this disclosure. Furthermore, many modifications may be made to adapt particular situations or materials to the teachings of this disclosure without departing from the essential scope of this disclosure. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed as the best mode contemplated for carrying out this disclosure, but rather that this disclosure will include all embodiments falling within the scope of the claims.

Claims

1. A transport refrigeration system, comprising: A transport refrigeration unit, which includes a compressor, a controller, and one or more valves; An energy storage device configured to provide electrical power to the transport refrigeration unit; as well as A smart charging connector that communicates electrically with the energy storage device and / or the transport refrigeration unit, and the smart charging connector can be connected to the power grid; in: The smart charging connector is configured to selectively control the supply of electrical power from the energy storage device and / or the power grid to the transport refrigeration unit. The smart charging connector is configured to, in response to connection of the smart charging connector to the power grid, switch the supply of electrical power to the transport refrigeration unit from being supplied by the energy storage device to being supplied by the power grid. The smart charging connector is configured to disconnect from the power grid, so that the supply of electrical power to the transport refrigeration unit is switched from being supplied by the power grid to being supplied by the energy storage device. The transport refrigeration system includes a power conversion unit configured to convert the amplitude, frequency, and phase of the electrical power signal provided by the energy storage device and / or the power grid. The smart charging connector includes a switch configured to allow the transport refrigeration unit to be directly connected to the power grid when the switch is closed. The smart charging connector includes: A power grid voltage detection unit is configured to detect characteristics of an electrical power signal supplied by the power grid, wherein the characteristics include the amplitude, phase, and frequency of the electrical power signal supplied by the power grid; and A communication unit configured to communicate with the power conversion unit to transmit and receive electrical power signals supplied by the power grid and / or the energy storage device.

2. The transport refrigeration system of claim 1, wherein the smart charging connector is configured to transmit the characteristics of the electrical power signal supplied by the power grid to the power conversion unit in response to the smart charging connector being connected to the power grid, and the power conversion unit is configured to, based on the characteristics of the electrical power signal supplied by the power grid, gradually convert the characteristics of the electrical power signal supplied from the energy storage device to the transport refrigeration unit into characteristics matching the characteristics of the electrical power signal supplied by the power grid.

3. The transport refrigeration system of claim 2, wherein the characteristics of the electrical power signal supplied from the energy storage device include the amplitude, frequency, and phase of the electrical power signal supplied from the energy storage device.

4. The transport refrigeration system of claim 2, wherein the power conversion unit is configured to gradually convert the characteristics of the electrical power signal supplied from the energy storage device to the transport refrigeration unit in consideration of the rate of change of continuous operation of the transport refrigeration unit.

5. The transport refrigeration system of claim 4, wherein the intelligent charging connector is configured to close the switch in response to receiving communication from the power conversion unit indicating that the characteristics of the electrical power signal supplied from the energy storage device have been converted to match the characteristics of the electrical power signal supplied by the power grid, so that the power grid is directly connected to the transport refrigeration unit.

6. The transport refrigeration system of claim 5, wherein the power conversion unit is configured to close the switch in response to supplying the power signal to the energy storage device by converting the characteristics of the power signal supplied from the power grid into characteristics matching the power signal required to charge the energy storage device.

7. The transport refrigeration system of claim 6, wherein the power conversion unit is configured to, in response to receiving a signal instructing a user to unplug the smart charging connector from the power source, replace the electrical power signal supplied from the power grid to the transport refrigeration unit with an electrical power signal supplied by the energy storage device, the electrical power signal supplied by the energy storage device having been converted by the power conversion unit to have characteristics matching those of the electrical power signal supplied by the power grid.

8. The transport refrigeration system of claim 7, wherein the smart charging connector is configured to, in response to an indication received from the power conversion unit by the smart charging connector that the transport refrigeration unit is powered entirely by the energy storage device, disconnect the switch and display an indication that the smart charging connector is ready to disconnect from the power source for user observation.

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