Patent ID: 12240296

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring toFIG.1, a transport refrigeration system20of the present disclosure is illustrated. In the illustrated embodiment, the transport refrigeration systems20may include a tractor or vehicle22, a container24, and an engineless transportation refrigeration unit (TRU)26. The container24may be pulled by a vehicle22. It is understood that embodiments described herein may be applied to shipping containers that are shipped by rail, sea, air, or any other suitable container, thus the vehicle may be a truck, train, boat, airplane, helicopter, etc.

The vehicle22may include an operator's compartment or cab28and a combustion engine42which is part of the powertrain or drive system of the vehicle22. In some instances, the vehicle22may be a hybrid or all electric configuration having electric motors to provide propulsive force for the vehicle. In some configurations, the TRU system26may be engineless. In some embodiments, a small engine or the engine of the vehicle22may be employed to power or partially power the TRU26. The container24may be coupled to the vehicle22and is thus pulled or propelled to desired destinations. The trailer may include a top wall30, a bottom wall32opposed to and spaced from the top wall30, two side walls34spaced from and opposed to one-another, and opposing front and rear walls36,38with the front wall36being closest to the vehicle22. The container24may further include doors (not shown) at the rear wall38, or any other wall. The walls30,32,34,36,38together define the boundaries of a cargo compartment40. Typically, transport refrigeration systems20are used to transport and distribute cargo, such as, for example perishable goods and environmentally sensitive goods (herein referred to as perishable goods). The perishable goods may include but are not limited to fruits, vegetables, grains, beans, nuts, eggs, dairy, seed, flowers, meat, poultry, fish, ice, blood, pharmaceuticals, or any other suitable cargo requiring cold chain transport. In the illustrated embodiment, the TRU26is associated with a container24to provide desired environmental parameters, such as, for example temperature, pressure, humidity, carbon dioxide, ethylene, ozone, light exposure, vibration exposure, and other conditions to the cargo compartment40. In further embodiments, the TRU26is a refrigeration system capable of providing a desired temperature and humidity range.

Referring toFIGS.1and2, the container24is generally constructed to store a cargo (not shown) in the compartment40. The engineless TRU26is generally integrated into the container24and may be mounted to the front wall36. The cargo is maintained at a desired temperature by cooling of the compartment40via the TRU26that circulates refrigerated airflow into and through the cargo compartment40of the container24. It is further contemplated and understood that the TRU26may be applied to any transport compartments (e.g., shipping or transport containers) and not necessarily those used in tractor trailer systems. Furthermore, the transport container24may be a part of the of the vehicle22or constructed to be removed from a framework and wheels (not shown) of the container24for alternative shipping means (e.g., marine, railroad, flight, and others).

The components of the engineless TRU26may include a compressor58, an electric compressor motor60, a condenser64that may be air cooled, a condenser fan assembly66, a receiver68, a filter dryer70, a heat exchanger72, an expansion valve74, an evaporator76, an evaporator fan assembly78, a suction modulation valve80, and a controller82that may include a computer-based processor (e.g., microprocessor) and the like as will be described further herein. Operation of the engineless TRU26may best be understood by starting at the compressor58, where the suction gas (e.g., natural refrigerant, hydro-fluorocarbon (HFC) R-404a, HFC R-134a . . . etc.) enters the compressor58at a suction port84and is compressed to a higher temperature and pressure. The refrigerant gas is emitted from the compressor58at an outlet port85and may then flow into tube(s)86of the condenser64.

Air flowing across a plurality of condenser coil fins (not shown) and the tubes86, cools the gas to its saturation temperature. The air flow across the condenser64may be facilitated by one or more fans88of the condenser fan assembly66. The condenser fans88may be driven by respective condenser fan motors90of the fan assembly66that may be electric. By removing latent heat, the refrigerant gas within the tubes86condenses to a high pressure and high temperature liquid and flows to the receiver68that provides storage for excess liquid refrigerant during low temperature operation. From the receiver68, the liquid refrigerant may pass through a sub-cooler heat exchanger92of the condenser64, through the filter-dryer70that keeps the refrigerant clean and dry, then to the heat exchanger72that increases the refrigerant sub-cooling, and finally to the expansion valve74.

As the liquid refrigerant passes through the orifices of the expansion valve74, some of the liquid vaporizes into a gas (i.e., flash gas). Return air from the refrigerated space (i.e., cargo compartment40) flows over the heat transfer surface of the evaporator76. As the refrigerant flows through a plurality of tubes94of the evaporator76, the remaining liquid refrigerant absorbs heat from the return air, and in so doing, is vaporized and thereby cools the return air.

The evaporator fan assembly78includes one or more evaporator fans96that may be driven by respective fan motors98that may be electric. The air flow across the evaporator76is facilitated by the evaporator fans96. From the evaporator76, the refrigerant, in vapor form, may then flow through the suction modulation valve80, and back to the compressor58. The expansion valve74may be thermostatic or electrically adjustable. In an embodiment, as depicted, the expansion valve74is thermostatic. A thermostatic expansion valve bulb sensor100may be located proximate to an outlet of the evaporator tube94. The bulb sensor100is intended to control the thermostatic expansion valve74, thereby controlling refrigerant superheat at an outlet of the evaporator tube94. It is further contemplated and understood that the above generally describes a single stage vapor compression system that may be used for HFCs such as R-404a and R-134a and natural refrigerants such as propane and ammonia. Other refrigerant systems may also be applied that use carbon dioxide (CO2) refrigerant, and that may be a two-stage vapor compression system. In another embodiment, the expansion valve74could be an electronic expansion valve. In this case the expansion valve is commanded to a selected position by the controller82based on the operating conditions of the vapor compression cycle and the demands of the system.

A bypass valve (not shown) may facilitate the flash gas of the refrigerant to bypass the evaporator76. This will allow the evaporator coil to be filled with liquid and completely ‘wetted’ to improve heat transfer efficiency. With CO2refrigerant, this bypass flash gas may be re-introduced into a mid-stage of a two-stage compressor58.

The compressor58and the compressor motor60may be linked via an interconnecting drive shaft102. The compressor58, the compressor motor60and the drive shaft102may all be sealed within a common housing104. The compressor58may be a single compressor. The single compressor may be a two-stage compressor, a scroll-type compressor or other compressors adapted to compress HFCs or natural refrigerants. The natural refrigerant may be CO2, propane, ammonia, or any other natural refrigerant that may include a global-warming potential (GWP) of about one (1).

Continuing withFIG.2, and with continued reference toFIG.1,FIG.2also illustrates airflow through the TRU26and the cargo compartment40. Airflow is circulated into and through and out of the cargo compartment40of the container24by means of the TRU26. A return airflow134flows into the TRU26from the cargo compartment40through a return air intake136, and across the evaporator76via the fan96, thus conditioning the return airflow134to a selected or predetermined temperature. The conditioned return airflow134, now referred to as supply airflow138, is supplied into the cargo compartment40of the container24through the refrigeration unit outlet140, which in some embodiments is located near the top wall30of the container24. The supply airflow138cools the perishable goods in the cargo compartment40of the container24. It is to be appreciated that the TRU26can further be operated in reverse to warm the container24when, for example, the outside temperature is very low.

A temperature sensor142(i.e., thermistor, thermocouples, RTD, and the like) is placed in the air stream, on the evaporator76, at the return air intake136, and the like, to monitor the temperature return airflow134from the cargo compartment40. A sensor signal indicative of the return airflow temperature denoted RAT is operably connected via line144to the TRU controller82to facilitate control and operation of the TRU26. Likewise, a temperature sensor146is placed in the supply airflow138, on the evaporator76, at the refrigeration unit outlet140to monitor the temperature of the supply airflow138directed into the cargo compartment40. Likewise, a sensor signal indicative of the supply airflow temperature denoted SAT14is operably connected via line148to the TRU controller82to facilitate control and operation of the TRU26.

System

Referring now toFIG.3, with continued reference toFIGS.1and2as well, the TRU26may include or be operably interfaced with a power supply interface shown generally as120. The power supply interface120may include, interfaces to/from various power sources denoted generally as122and more specifically as follows herein as well as one or more DC busses shown generally as125and more specifically125a,125b, . . .125n. In an embodiment, the power sources122may include, but not be limited to an energy storage device152, generator162, and grid power,182. Each of the power sources122may be configured to selectively power the TRU26as described further herein, including compressor motor60, the condenser fan motors90, the evaporator fan motors98, the controller82, and other components99of the TRU26that may include various solenoids and/or sensors). The controller82through a series of data and command signals over various pathways108may, for example, control the application of power to the electric motors60,90,98as dictated by the cooling needs of the TRU26.

The engineless TRU26may include an AC or DC architecture with selected components employing alternating current (AC), and others employing direct current (DC). For example, in an embodiment, the motors60,90,98may be configured as AC motors, while in other embodiments, the motors60,90,98may be configured as DC motors. The operation of the of the power sources122as they supply power to the TRU26may be managed and monitored by the TRU controller82and interfaced from the DC bus125to the power management system190. The power management system190is configured direct the power from the various power sources122, and the like, via DC bus125based on various requirements of the TRU26. In an embodiment, the TRU controller82receives various signals indicative of the operational state of the TRU26and determines the power requirements for the TRU system26accordingly and directs the components of the power supply interface120and specifically the power management system190to direct power accordingly to address the requirements of the TRU26.

In one embodiment, the TRU system26is controlled to a temperature setpoint value selected by the user. The TRU controller82monitors the RAT and optionally the SAT as measured by the temperature sensors142and146respectively. The TRU controller82estimates the power requirements for the TRU26based on the RAT (among others) and provides commands accordingly to the various components of the power supply interface120and specifically the power management system190, energy storage system150, and generator power converter164to manage the generation, conversion, and routing of power in the power supply interface120and TRU system26. By using the measured RAT and the setpoint value, an estimate to power demand is made. More specifically, in one embodiment, if the (RAT-setpoint value) is above a first threshold (e.g., >10 degrees F.), then full power (e.g., at a known voltage supply, current demand is known) is needed by the TRU system26. If the (RAT-setpoint value) is between first threshold and second threshold, current requirement is limited (at known voltage) to achieve a mid-range power (e.g., ˜50% power or something less than 100%). If the (RAT-setpoint value) is below second threshold, current is limited (at voltage) to achieve a minimum power (e.g., ˜20% power).

The TRU controller82is configured to control the components in the TRU26as well as the components of the power supply interface120in accordance with operating needs of the transport refrigeration system20. The TRU controller82is communicatively coupled to the power management system190, the grid power source182, the energy storage system150, and the generator power converter164or generator162. For the TRU power demand, the TRU controller82, using additional information from each of the power sources122provides instructions to affect the grid power source182output, the generator162and generator power converter164output, the charge/discharge of the energy storage system150, all to enable and configure providing power as required by the TRU26. Additionally, the TRU controller82provides instructions for various components in the power supply interface120to manage the power flow to the DC Bus125and thereby to the power management system190depending upon the operational status of the various power sources (i.e. grid power182, energy storage device152and generator162) and as based on the TRU26power demand.

In an embodiment, the power management system190includes a DC/AC converter194. The DC/AC converter194is configured to receive DC power on the DC bus125denoted in this instance125a(e.g., second DC voltage V2, a second DC current I2from the generator power converter165; and/or VG, IG185; and/or DC voltage155from the energy storage device152; alone or as combined) and generate three phase AC power195(e.g., at AC voltage V2, AC current I2a frequency f2), for providing power to the TRU system26. In an embodiment, the DC/AC converter194includes a voltage control function, a current control function, and a frequency control function, each configured to facilitate the conversion. In an embodiment, the TRU controller82provides command signals denoted by line191, to the power management system190. The commands are based, at least, on the power consumption requirements of the TRU26as discussed further herein. In addition, the TRU controller82may receive status information also depicted by line191regarding the DC/AC converter194. In an embodiment, the communications may be over standard communication interfaces such as CAN, RS-485, and the like. Moreover, as is discussed further herein, the communications may be wired or wireless.

As described further herein, there are three power sources122grid power182, generator162/generator power converter164and energy storage device152. If the TRU26is “On” and operating, the TRU controller82knows, the power requirements for the TRU system26, and thereby, what power is needed. The TRU controller82is also programmed to ascertain whether or not grid power (e.g.,182) is available or not. If the grid power is available and TRU is On and energy storage device152(e.g., battery) SOC indicates a full charge, grid power will satisfy TRU system26power demand. Conversely, if grid power182is available and TRU On and the energy storage device is not fully charged, TRU power demand is satisfied as first priority and then DC/DC converter156is be activated to provide necessary charging to energy storage device152as second priority. Moreover, if grid power182is available and TRU is “Off” and the energy storage device152is not fully charged, the DC/DC converter156will be activated to provide necessary charging current. If grid power182is not available and generator/generator power converter162/164is not operable, all TRU power demand is satisfied by the energy storage system150via the energy storage device152. Finally, if grid power182is not available and generator/generator power converter162/164is operable, then TRU power demand is satisfied by both the generator162& energy storage system150.

As described herein, in operation, the TRU controller82identifies the power requirements for the TRU26at least partially based on the RAT. The TRU controller82conveys the power requirements to the power management system190and/or the generator power converter164to convert the first three phase AC power163or first DC power163ato the second DC power165as necessary to satisfy the requirements of the TRU26and the energy storage system150and specifically the charging requirements of the energy storage device152.

The DC bus125and thereby, the power management system190may receive power from a grid power source182when it is available. In an embodiment the grid power source182is interfaced to the DC bus125and the power management system190via a grid power converter184. In an embodiment, the power management system190may be a stand-alone unit, or integral with the TRU26. The grid power source182is generally conventional three phase AC power 220/480 VAC at 60 or 400 Hz. In an embodiment, the grid power converter184is a conventional AC/DC converter operable to convert the three phase AC power from the grid power source182to a DC voltage and current. The grid power converter184in one or more embodiments generates a grid DC power185including DC voltage VG, and DC current IG. The grid DC power185and is transmitted from the grid power converter184to the DC bus125and the power management system190or otherwise as described herein.

The DC bus125and power management system190receives power from a generator162directly and/or via a generator power converter164. The generator162can be axle or hub mounted configured to recover rotational energy when the transport refrigeration system20is in motion and convert that rotational energy to electrical energy, such as, for example, when the axle of the vehicle22is rotating due to acceleration, cruising, or braking. In an embodiment, the generator162is configured to provide a first three phase AC power163comprising voltage V1, an AC current I1at a given frequency f1denoted by reference numeral163. The generator162may be asynchronous or synchronous. In another embodiment, the generator162may be DC, providing a first DC power163aincluding a DC voltage and DC current denoted as V1a, and DC current I1a. The generator power converter164in one or more embodiments generates a second DC power165including DC voltage V2, and DC current I2. The second DC power165and is transmitted from the generator power converter164to the DC bus125and thereby the power management system190or otherwise as described herein.

Energy Storage System

Continuing withFIG.3and the architecture of the power supply interface120and the various power sources122employed to power the TRU26and the components thereof. In an embodiment, one of the power sources122may include, but not be limited to an energy storage system150operably coupled to the power management system190. The energy storage system150transmits DC power155via DC bus125bto, and receives DC power157from the DC bus125. The energy storage system150may include, but not be limited to the energy storage device152, and a battery management system154. In an embodiment, the battery management system154is a part of, and integral with, the energy storage device152. In this embodiment DC bus125aand125bare directly connected.

In an embodiment the DC voltages from the power sources122including DC voltage185from the grid power source182and/or DC voltage V2, I2165from the generator power converter164combines to form the DC voltage on the and current on bus125a,125bwhich is directly coupled to the energy storage device152to the to charge and store energy on the energy storage device152. Conversely, in other embodiments, for example when grid power source182is not available, the energy storage device152supplies DC voltage and current155directly to the DC bus125b,125aand the power management system190for powering the TRU26. In another embodiment, the energy storage system150further includes a DC/DC converter156. In one embodiment, the DC bus125, and more specifically125aprovides DC power157to a DC/DC converter156to formulate a DC voltage and current155on DC bus125bto charge and store energy on the energy storage device152. Conversely, in other embodiments the energy storage device152supplies DC voltage and current155via DC bus125bto the DC/DC converter156operating as a DC/DC converter to supply a DC power157to the DC bus125,125a, and the power management system190for powering the TRU26. It should be appreciated that as described herein, the DC/DC converter156is bidirectional, enabling conversions in both directions to facilitate charging and discharging the energy storage device152. While the DC/DC converter156is described as bidirectional, such description is merely for the purposes of illustration. In operation, the DC/DC converter156may be a single integrated unit, or multiple units configured in parallel to operate in opposite directions. It is also noteworthy to appreciate that in the various embodiments described herein, numerous architectures are described based on the interconnection between the various power sources122. More specifically, the interconnection between power sources122, e.g., grid power source182, generator162and the DC/AC converter194of the power management system190with the energy storage device152, based on the optional application of the optional DC/DC converter156. In the various architectures, where the energy storage device152is directly connected (e.g.125adirectly connected to125b), that portion of the bus is termed variable as the voltage is capable of variation based on the state of charge of the energy storage device152. On the other hand, in the instances where the DC/DC converter is employed, the portions of the DC bus directly connected (e.g.,125b) to the energy storage device152and at the input connection to the DC/DC converter are considered variable, while the portion at the output of the DC/DC converter156connected to the DC bus125, (e.g.,125a) are considered fixed and regulated.

The battery management system154monitors the performance of the energy storage device152. For example, monitoring the state of charge of the energy storage device152, a state of health of the energy storage device152, and a temperature of the energy storage device152. Examples of the energy storage device152may include a battery system (e.g., a battery or bank of batteries), fuel cells, flow battery, ultracapacitors, and others devices capable of storing and outputting electric energy that may be direct current (DC). The energy storage device152may include a battery system, which may employ multiple batteries organized into battery banks.

If the energy storage system150includes a battery system for the energy storage device152, the battery system may have a voltage potential within a range of about two-hundred volts (200V) to about six-hundred volts (600V). Generally, the higher the voltage, the greater is the sustainability of electric power which is preferred. However, with increases in the voltage, the size and weight of the battery/batteries in an energy storage device152increase. Increased size and weight are generally not preferred when transporting cargo. Additionally, if the energy storage device152is a battery, then in order to increase either voltage and/or current, the batteries need to be connected in series or parallel depending upon electrical needs. Higher voltages in a battery energy storage device152will require more batteries in series than lower voltages, which in turn results in bigger and heavier battery energy storage device152. A lower voltage and higher current system may be used, however such a system may require larger cabling or bus bars. As a result, commonly the selection and integration of the energy storage device152, in a power system requires tradeoffs between capacity current, size weight and the like. In addition, the voltage and current capability of the energy storage device152may also require tradeoffs on the architecture of the power system such as direct connection or employing a DC/DC converter as described herein.

In one embodiment, the energy storage device152may be contained within the structure27of the TRU26. In an embodiment, the energy storage device152is located with the TRU26, however, other configurations are possible. In another embodiment, the energy storage device152may be located with the container24such as, for example, underneath the cargo compartment40. Likewise, the DC/DC converter156may be located with the container24such as, for example, underneath the cargo compartment40, however, in some embodiments it may be desirable to have the DC/DC converter156in close proximity to the power management system190and/or the TRU26and TRU controller82. It will be appreciated that in one or more embodiments, while particular locations are described with respect to connection and placement of selected components including the energy storage device152and/or DC/DC converter156, such descriptions are merely illustrative and are not intended to be limiting. Varied location, arrangement and configuration of components is possible and within the scope of the disclosure.

The battery management system154and DC/DC converter156are operably connected to and interface with the TRU controller82. The TRU controller82receives information regarding the status of energy storage system150, including the energy storage device152to provide control inputs to the DC/DC converter156to monitor the energy storage device152, as well as control charge and discharge rates for the energy storage device152.

AC Gen/DC Converter

In an embodiment associated with the generator power converter164is an AC/DC converter and configured to receive the three phase AC power163(e.g., at AC voltage V1, AC current I1a frequency f1), from the generator162and convert it to a DC power denoted165comprising a second DC voltage V2, a second DC current12. The second DC power165is transmitted from the generator power converter164to the DC bus125and power management system190. In an embodiment, the generator power converter164is configured to provide the second DC power165based of the requirements of the TRU26. In an embodiment, the generator power converter164includes a voltage control function166, a current control function167, are each configured to facilitate the conversion. In an embodiment, the TRU controller82provides command signals denoted169, and170to a voltage control function166, current control function167, respectively. The command signals169, and170are generated by the TRU controller82based on the power consumption requirements of the TRU26as discussed further herein. In addition, the TRU controller82may receive status information as depicted by171,172regarding the generator power converter164, and generator162respectively. Likewise, the generator power converter may receive control signal or provide status signals to TRU controller82, the power management system190, or energy storage system150for mode selection and diagnostic purposes. In an embodiment, the communications may be over standard communication interfaces such as CAN, RS-485, and the like. Moreover, as is discussed further herein, the communications may be wired or wireless.

In this embodiment, the generator power converter164, the voltage control function166includes a voltage regulation function and is configured to monitor the output voltage from the generator162and maintains a constant DC voltage out of the voltage control function166. The voltage control function166communicates status to the TRU Controller82. The current control function167monitors and communicates to the TRU26the status of current draw from the generator162. In an embodiment, the current may be limited depending on the power demands of the TRU26. Finally, in an embodiment a frequency converter function168may also monitors the frequency of the three phase power163produced by the generator162to facilitate the conversion of the three phase power163to the second DC power165as determined by the voltage control function166and the TRU controller82for supply to the power management system190and ultimately the TRU26. The generator power converter164may be a stand-alone unit configured to be in close proximity to or even integral with the generator162.

DC Gen/DC Converter

In yet another embodiment, for example, when the generator162is a DC generator, the generator power converter164is an DC/DC converter and configured to receive DC power163a(e.g., at DC voltage V1a, DC current I1a), from the generator162and convert it to the second DC power denoted165acomprising a second DC voltage V2a, a second DC current I1a. The second DC power165ais transmitted from the generator power converter164to the power management system190. Once again, as described above, the generator power converter164is configured to provide the second DC power165abased of the requirements of the TRU26as described above. In this embodiment, the generator power converter164including the voltage control function166, and the current control function167, are each configured to facilitate the DC/DC conversion. In this embodiment, once again the TRU controller82provides command signals denoted169, and170to a voltage control function166, current control function167respectively, based on the power consumption requirements of the TRU26as discussed further herein. In this embodiment, the voltage control function166includes a voltage regulation function and is configured to monitor the output DC voltage from the generator162and maintains a constant DC voltage out of the voltage control function166for supply to the DC bus125and power management system190and ultimately the TRU26. The current control function167monitors and communicates to the TRU26the status of current draw from the generator162. Once again, in an embodiment, the communications may be over standard communication interfaces such as CAN, RS-485, and the like. Moreover, as is discussed further herein, the communications may be wired or wireless.

Power Flows

Continuing withFIG.3, as described earlier, the power supply interface120may include, interfaces to various power sources122managed and monitored by the TRU controller82. The TRU controller82and the power management system190manages and determines electrical power flows in the power supply interface120based upon the operational needs of the TRU26and the capabilities of the components in the power supply interface120, (e.g., generator162, converter164, energy storage device152, and the like. The TRU controller determines the status of various power sources122, controls their operation, and directs the power to and from the various power sources122and the like based on various requirements of the TRU26.

In an embodiment there are five primary power flows associated with the power supply interface120and specifically the DC bus125managed by the TRU controller82and the power management system190. First, the power into the/dc bus125supplied via the generator162or generator power converter164, e.g., second DC power165). Second, the power supplied to the DC bus125when operably connected to grid power source182. Third the power supplied to the DC bus from an energy storage device152. Fourth, the power directed from the DC bus125to the energy storage device152. Finally, the DC power directed to the power management system190and TRU26from the DC bus125.

The power flows will be transferred through different paths based on the requirements placed on the power management system190and particular configuration of the power supply interface120. The DC bus125and the power management system190operates as a central power bus to connect various power sources122together to supply the power needs of the TRU26. The TRU controller and power management system190controls switching, directing, or redirecting power to/from the five power flows as needed to satisfy the power requirements of the TRU26.

Turning now toFIGS.4A-4Heach providing a simplified diagram depicting each of the various possible power flow combinations in the power supply interface120associated with the DC bus125.FIGS.4A-4Cdepict power flows for power supplied from the generator162and/or generator power converter164(e.g., second DC power). Referring now toFIG.5A, in an embodiment, the logic employed by the TRU controller82for directing the power on the DC bus125and to the power management system190if the TRU26is operating. If so, and the energy storage system150indicates that the energy storage device120is exhibiting a charge state that is less than a selected threshold, then the power on the DC bus125is directed to the power management system190and thereby the TRU26and the energy storage system150for recharging the energy storage device152. In an embodiment, priority is given to satisfying the power requirements of the TRU26. Any remaining power may be directed to the recharging application for the energy storage system150. It should be appreciated that while particular threshold of 80% is disclosed and employed for the described embodiments, such values and description are merely illustrative. Other values and applications for the thresholds are possible.

Referring now toFIG.4Bas well, the figure depicts a second instance for power flows for power supplied from the generator162and/or generator power converter164. In this embodiment, if the TRU26is operating, and the energy storage system150indicates that the energy storage device152is exhibiting a state of charge that is in excess of a selected threshold, then the power on the DC bus125is directed only to the power management system190to power only the TRU26, (as the and the energy storage system150does not yet require recharging). Similarly, in yet another embodiment, as depicted byFIG.4C, a third power flow for power supplied from the generator162and/or generator power converter164. In this embodiment, the logic employed by the TRU controller82for directing the power to the power management system190addresses an instance when the TRU26is inoperative, and the energy storage system150indicates that the energy storage device152is exhibiting a state of charge that is less than a selected threshold (in this instance 100%, though other thresholds are possible). In this embodiment, the DC power on the DC bus125is directed only to the energy storage system150for recharging the energy storage device152.

Turning now toFIGS.4D-4F, which depict power flows for power supplied from the grid power source182. In an embodiment as depicted inFIG.4D, the logic employed by the TRU controller82for directing the power from the grid power source182determines if the TRU26is operating and the generator162(or the generator power converter164) is inoperative. If so, and the energy storage system150indicates that the energy storage device152is exhibiting a charge state that is less than a selected threshold, then power is directed from the DC bus125to both the power management system190and then the TRU system26and the energy storage system150for recharging the energy storage device152. In an embodiment, once again, priority is given to satisfying the power requirements of the TRU system26. Any remaining power may be directed to the recharging application for the energy storage system150. It should be appreciated that while particular threshold of 80% is disclosed and employed for the described embodiments, such values and description are merely illustrative. Other values and applications for the thresholds are possible.

Referring now toFIG.4Eas well, the figure depicts a second instance for power flows for power supplied from the grid power source182when the generator162is inoperative. In this embodiment, if the TRU26is operating, and the energy storage system150indicates that the energy storage device152is exhibiting a state of charge that is in excess of a selected threshold, then the DC power on the DC bus125is directed only to the power management system190directs and to the TRU26, (as the energy storage system150does not yet require recharging). Similarly, in yet another embodiment, as depicted byFIG.4F, a third power flow for power supplied from the grid power source182when the generator162is inoperative. In this embodiment, the logic employed by the TRU controller82for directing the power on the DC bus125addresses an instance when the TRU26is also inoperative, and the energy storage system150indicates that the energy storage device152is exhibiting a state of charge that is less than a selected threshold (in this instance 100%, though other thresholds are possible). In this embodiment, the power on the DC bus125is directed only to the energy storage system150for recharging the energy storage device152. In an embodiment, priority is given to satisfying the power requirements of energy storage system150.

Turning nowFIGS.4G and4H, which depict power flows for power supplied to the power management system190and the TRU26under selected conditions for operating from the energy storage system150as well. InFIG.4Gpower flows to the TRU26are provided from the generator162and/or generator power converter164(e.g., second DC power165) as well as from the energy storage system150. In an embodiment, the logic employed by the TRU controller82for directing the power to the DC bus125and the power management system190determines if the TRU26is operating. If so, and the energy storage system150indicates that the energy storage device152is exhibiting a charge state of greater than a selected threshold, then power from both the generator162(or generator power converter164) and the energy storage system150is directed to DC bus125and then to the power management system190and thereby the TRU26. In an embodiment, a threshold of 10 percent is employed for the state of charge of the energy storage device152. In this embodiment, power is provided by the energy storage system150and thereby discharging the energy storage device152. In an embodiment, priority is given to satisfying the power requirements of the TRU26. This embodiment may be employed under conditions where the output power of the generator162and/or generator power converter164is less that that needed to operate the TRU26. It should be appreciated that while particular threshold of 10% is disclosed and employed for the described embodiments, such values and description are merely illustrative. Other values and applications for the thresholds are possible. For example, in some instances it may be desirable prioritize operation of the TRU26such that fully draining the energy storage device152is acceptable. Likewise, in other embodiments, it may be desirable to modify the function or curtail the operation of the TRU26to avoid excessively discharging the energy storage device152.

Referring now toFIG.4Has well, the figure depicts a second instance for power flows from the energy storage system150alone. In this embodiment, if the TRU26is operating, but the generator162and/or the generator power converter164is inoperative, if the energy storage system150indicates that the energy storage device152is exhibiting a state of charge that is in excess of a selected threshold, then the power on the DC bus is directed to the power management system190, which then provides power to the TRU26. In an embodiment a threshold of 10 percent is employed for the state of charge of the energy storage device152. In this embodiment, power is provided by the energy storage system150and thereby discharging the energy storage device152. In an embodiment, priority is given to satisfying the power requirements of the TRU26. Once again, this embodiment may be employed under conditions where the output power of the generator162and/or generator power converter164is less that that needed to operate the TRU26. It should be appreciated that while particular threshold of 10% is disclosed and employed for the described embodiments, such values and description are merely illustrative. Other values and applications for the thresholds are possible. For example, in some instances it may be desirable prioritize operation of the TRU26such that fully draining the energy storage device152is acceptable. Likewise, in other embodiments, it may be desirable to modify the function or curtail the operation of the TRU to avoid excessively discharging the energy storage device152.

Returning toFIG.3, in another embodiment and specialized mode of operation and power flow for the TRU system26and the power supply interface120. In this embodiment, referred to as a fail operational or “limp home” mode, the power supply interface120is configured such that, in selected modes of operation power is directed to the TRU26from the tractor or vehicle22. In an embodiment, should the energy storage device152exhibit a SOC below a selected threshold e.g., <10% and the generator162/generator power converter164is not operable but the TRU system26is operable and requires power, TRU power could be drawn from the power system of the tractor or truck. (i.e. tie into the energy storage device or generator of the tractor/truck). Moreover, it should be appreciated that the described embodiments while generally referring the generator162being installed on the trailer portion of the vehicle,22, such description is merely illustrative. In another embodiment, the generator162or another generator could be installed at a hub or axle of the tractor portion of the vehicle22without loss of generality and still be fully applicable to the described embodiments. In an embodiment, the tractor/truck power may be routed to the power supply interface120through a grid plug189. Alternately connectable between the grid power source182and the vehicle power. For example, in operation, when vehicle22trailer is in operation, for example, on delivery, grid plug189would be plugged into the tractor/trailer's electric PTO and act as mobile grid source. The TRU controller82would be programmed to determine if the grid plug is active and if so, to pull power (or supplement generator power) only if energy storage device SOC is below threshold as alternative to modify the function or curtail the operation of the TRU system26.

Turning now toFIGS.5A-5H,FIGS.5A-5Hdepict a plurality of possible configurations for the power supply interface120.FIG.5Adepicts a simplified block diagram of the power supply interface120as described herein.FIG.5Adepicts the single DC bus125in a variable configuration.FIG.5Bdepicts the alternate embodiment of the power supply interface120as described above. In this embodiment, the DC bus is split with a variable side125bbetween the energy storage device152and the DC/DC converter156and a fixed DC bus125,125aon the output side of the DC/DC converter156of the energy storage system150.

FIG.5Cdepicts a simplified block diagram of the power supply interface320in accordance with another embodiment as described herein.FIG.5Cdepicts a configuration of the power supply interface320where the grid power supply182and grid power converter184are commonly connected with the energy storage device152on the DC bus125bin a variable configuration. In this embodiment the DC/DC converter156isolates the variable DC bus125bfrom the fixed DC bus125awhich includes the output of the DC/DC converter156of the energy storage system150and the output of the generator power converter164commonly connected with the DC/AC converter192of the power management system190to provide power to the TRU system26.

Similarly,FIG.5Ddepicts a simplified block diagram of the power supply interface420in accordance with yet another embodiment as described herein.FIG.5Ddepicts a configuration of the power supply interface420where the grid power supply182and grid power converter184are commonly connected with the generator162and the output of the generator power converter164with energy storage device152on the DC bus125bin a variable configuration. In this embodiment the DC/DC converter156isolates the variable DC bus125bfrom the fixed DC bus125awhich includes the output of the DC/DC converter156of the energy storage system150commonly connected with the DC/AC converter192of the power management system190to provide power to the TRU system26.

Likewise,FIG.5Edepicts a simplified block diagram of the power supply interface520in accordance with yet another embodiment as described herein.FIG.5Edepicts a configuration of the power supply interface520where the grid power supply182and grid power converter184are connected in series with the DC/DC converter156forming the fixed DC bus denoted125cbetween the grid power converter and the DC/DC converter156of the energy storage system150. In this embodiment the DC/DC converter156isolates the fixed DC bus125cfrom the variable DC bus125a. The generator162and the output of the generator power converter164along with the energy storage device152are connected on the variable DC bus125ain a variable configuration with the DC/AC converter192of the power management system190to provide power to the TRU system26.

Likewise,FIG.5Fdepicts another simplified block diagram of the power supply interface620in accordance with still another embodiment as described herein.FIG.5Fdepicts a configuration of the power supply interface620where the grid power supply182and grid power converter184as well as the generator162and the output of the generator power converter164are connected with the DC/DC converter156forming the fixed DC bus denoted once again125c. Once again DC/DC converter156of the energy storage system isolates the fixed DC bus125cfrom the variable DC bus125a. In addition, the output of the DC/DC converter156of the energy storage system150is connected along with the energy storage device152on the variable DC bus125ain a variable configuration with the DC/AC converter192of the power management system190to provide power to the TRU system26.

Likewise,FIG.5Gdepicts a simplified block diagram of the power supply interface720in accordance with still yet another embodiment as described herein.FIG.5Gdepicts a configuration of the power supply interface720where the generator162and the output of the generator power converter164are connected with the energy storage device152on the variable DC bus125ain a variable configuration. The DC/DC converter156of the energy storage system forming the fixed DC bus denoted once again125c, once again DC/DC converter156isolates the fixed DC bus125cfrom the variable DC bus125a. In addition, the output of the DC/DC converter156of the energy storage system150is connected along with grid power converter184to fixed DC bus125c, providing power the DC/AC converter192of the power management system190to provide power to the TRU system26.

Finally,FIG.5Hdepicts a simplified block diagram of the power supply interface820in accordance with still yet another embodiment as described herein.FIG.5Gdepicts a configuration of the power supply interface820where the generator182is connected to the generator power converter184to a fixed voltage DC bus125c. The grid power source182via the output of the grid power converter184is connected with the energy storage device152on the variable DC bus125ain a variable configuration. The DC/DC converter156of the energy storage system150is connected to the generator power converter164on the fixed DC bus125c. Once again DC/DC converter156isolates the fixed DC bus125cfrom the variable DC bus125a. In addition, the output of the DC/DC converter156of the energy storage system150is connected along with the energy storage device152on the variable DC bus125aand providing power the DC/AC converter192of the power management system190to provide power to the TRU system26.

The TRU26may further include a renewable power source110(FIG.1) configured to recharge the batteries of the energy storage device152. One embodiment of a renewable power source110may be solar panels mounted, for example, to the outside of the top wall30of the container24(also seeFIG.1). For example the renewable power source110could generate all or a portion of the needed low voltage DC power for the TRU controller82. Once again, such a configuration simplifies the wiring and routing of the system design by eliminating an additional set of DC cabling from the energy storage device152beyond the HV cabling going toe the AC/DC converter156.

Benefits of the present disclosure when compared to more traditional systems include no fuel carriage, fuel system and fuel consumption, and a refrigeration unit that emits less noise and no combustion byproducts. Yet further, the present disclosure includes an energy storage device that is conveniently and efficiently recharged to meet the power demands of the refrigeration unit.

As described above, embodiments can be in the form of processor-implemented processes and devices for practicing those processes, such as a processor. Embodiments can also be in the form of computer program code containing instructions embodied in tangible media, such as network cloud storage, SD cards, flash drives, floppy diskettes, CD ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes a device for practicing the embodiments. Embodiments can also be in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into an executed by a computer, the computer becomes a device for practicing the embodiments. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.

The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value.

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

While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.