Patent Description:
Traditional refrigerated cargo trucks or refrigerated tractor trailers, such as those utilized to transport cargo via sea, rail, or road, is a truck, trailer or cargo container, generally defining a cargo compartment, and modified to include a refrigeration system located at one end of the truck, trailer, or cargo container. Refrigeration systems typically include a compressor, a condenser, an expansion valve, and an evaporator serially connected by refrigerant lines in a closed refrigerant circuit in accord with known refrigerant vapor compression cycles. A power unit, such as a combustion engine, drives the compressor of the refrigeration unit, and may be diesel powered, natural gas powered, or other type of engine. In many tractor trailer transport refrigeration systems, the compressor is driven by the engine shaft either through a belt drive or by a mechanical shaft-to-shaft link. In other systems, the engine of the refrigeration unit drives a generator that generates electrical power, which in-turn drives the compressor.

With current environmental trends, improvements in transportation refrigeration units are desirable particularly toward aspects of efficiency, sound and environmental impact. With environmentally friendly refrigeration units, improvements in reliability, cost, and weight reduction is also desirable.

<CIT> discloses a hybrid power system for a transport refrigeration unit.

Viewed from a first aspect, a transportation refrigeration unit (TRU) and power system as claimed in claim <NUM> is provided. The TRU and power system comprising a compressor configured to compress a refrigerant, the compressor having a compressor motor configured to drive the compressor, an evaporator heat exchanger operatively coupled to the compressor, an evaporator fan configured to provide return airflow from a return air intake and flow the return airflow over the evaporator heat exchanger, and a return air temperature (RAT) sensor disposed in the return airflow and configured measure the temperature of the return airflow. The TRU and power system also includes a TRU controller operably connected to the RAT sensor and configured to execute a process to determine an AC power requirement for the TRU based on at least the RAT. The TRU and power system also includes a generator power converter configured to receive a generator three phase AC power provided by an AC generator and transmit a second DC power, an energy storage system configured to receive the second DC power and provide/receive a three phase AC power, and a power management system configured to receive the three phase AC power and direct at least a portion of the three phase AC power the TRU based on the AC power requirement. The generator power converter is operably connected to the TRU controller, the generator power converter including a voltage control function, a current control function, wherein at least the voltage control function is responsive to the AC power requirement.

Optionally, a grid power source is configured to provide grid three phase AC power to the power management system.

The generator power converter may include an AC/DC converter and the generator three phase AC power exhibits a first AC voltage and a first AC current, at a first frequency, and the second DC power exhibits a second DC voltage and a second DC current.

The energy storage system may include an energy storage device, a switching device; and at least one of an DC/AC converter configured to provide another three phase AC power to the power management system based on the AC power requirement and an AC/DC converter configured to convert at least a portion of the three phase AC power to supply the energy storage device.

The switching device may be configured to direct DC power flows in the energy storage system based on the AC power requirement. The directing includes directing the second DC voltage to at least one of the energy storage device and the DC/AC converter and DC/AC converter, directing DC power from the energy storage device to the DC/AC converter, and receiving DC power from the AC/DC converter and providing it to the energy storage device.

The energy storage device may comprise at least one of a battery, fuel cell, and flow battery.

A battery management system may be operably connected to the TRU controller and configured to monitor at least a state of charge of the energy storage device.

The DC/AC converter and AC/DC converter may be integrated and wherein the DC/AC converter or AC/DC converter is operably connected to the TRU controller and configured to direct power flows to the power management system and from the power management system based on at least one of the AC power requirement and the state of charge of the energy storage device.

The another three phase AC power may be synchronized to match grid three phase AC power.

The power management system may be configured to receive a three phase AC power from the energy storage system configured to provide a three phase AC power and a grid power connection configured to provide a three phase grid power to the power management system and wherein the power management system is configure to provide a selected three phase AC power to at least one of the TRU and the energy storage system.

The power management system may include a power control switching device, the power control switching device responsive to the TRU controller and configured to direct a plurality of power flows in the TRU and power system, the plurality of power flows based on at least the AC power requirement, a state of charge of an energy storage device of the energy storage system.

A first portion of power flows of the plurality of power flows may include, receiving a grid three phase AC power from the grid if the grid power source is operative, and directing at least a portion of the grid three phase AC power to the TRU and energy storage system if the TRU is operative and an energy storage device of the energy storage system exhibits a state of charge less than a selected threshold, or directing at least a portion of the grid three phase AC power to the TRU, if the TRU is operative and an energy storage device of the energy storage system exhibits a state of charge greater than or equal to about the selected threshold, or directing at least a portion of the grid three phase AC power to the energy storage system if the TRU is not operative and an energy storage device of the energy storage system exhibits a state of charge less than a second selected threshold.

A second portion of power flows of the plurality of power flows may include, receiving a three phase AC power from the energy storage systems, receiving a grid three phase AC power from the grid power source if the grid AC power source is operative, synchronizing and combining the three phase AC power from the energy storage system and the grid three phase AC power, and directing the combined three phase AC power to the TRU if the TRU is operative and an energy storage device of the energy storage system exhibits a state of charge greater than or equal to about another selected threshold.

Viewed from a second aspect, a method of generating and directing power to a transportation refrigeration unit (TRU) system as claimed in claim <NUM> is provided. The TRU has a compressor configured to compress a refrigerant, an evaporator heat exchanger operatively coupled to the compressor; an evaporator fan configured to provide return airflow from a return air intake and flow the return airflow over the evaporator heat exchanger; a return air temperature (RAT) sensor disposed in the return airflow and configured measure the temperature of the return airflow; and a TRU controller. The method includes operably connected to the RAT sensor to the TRU controller, determining an AC power requirement for the TRU based on at least the RAT, and operably connecting a generator power converter, to an AC generator, the generator power converter configured to receive a generator three phase AC power provided by an AC generator and transmit a second DC power. The generator power converter is operably connected to the TRU controller, the generator power converter including a voltage control function, a current control function, wherein at least the voltage control function is responsive at least in part to the AC power requirement. The method also includes operably connecting an energy storage system, the energy storage system operable to receive the second DC power and provide/receive a three phase AC power, and operably connecting a power management system to the generator power converter and the TRU, the power management system configured receive the second three phase AC power to direct power the TRU based on the AC power requirement.

The method may include connecting a grid power source to provide grid three phase AC power to the power management system.

The generator power converter may include an AC/DC converter and the generator three phase AC power exhibits a first AC voltage and a first AC current at a first frequency, and the second DC power exhibits a second DC voltage and a second DC current.

The energy storage system may comprise an energy storage device, a switching device, and at least one of an DC/AC converter configured to provide another three phase AC power to the power management system based on the AC power requirement and an AC/DC converter configured to convert at least a portion of the three phase AC power to supply the energy storage device.

The method may include configuring the switching device to direct DC power flows in the energy storage system based on the AC power requirement. The directing includes applying the second DC voltage to at least one of the energy storage device and the DC/AC converter and DC/AC converter, applying DC power from the energy storage device to the DC/AC converter, and receiving DC power from the AC/DC converter and providing it to the energy storage device.

The method may include configuring the power management system with a power control switching device, the power control switching device responsive to the TRU controller and configured to direct a plurality of power flows in the TRU and power system, the plurality of power flows based on at least the AC power requirement, a state of charge of an energy storage device of the energy storage system.

Technical effects of embodiments of the present disclosure include a transportation refrigeration unit coupled to and powered by an external generator system via a generator power converter, where the power generated by the generator and converted by the generator power converter is based on an AC power requirement of the transportation refrigeration unit.

The subject matter which is regarded as the disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification.

Referring to <FIG>, a transport refrigeration system <NUM> of the present disclosure is illustrated. In the illustrated embodiment, the transport refrigeration systems <NUM> may include a tractor or vehicle <NUM>, a container <NUM>, and a transportation refrigeration unit (TRU) <NUM>. The container <NUM> may be pulled by a vehicle <NUM>. 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 vehicle <NUM> may include an operator's compartment or cab <NUM> and a combustion engine <NUM> which is part of the powertrain or drive system of the vehicle <NUM>. In some instances the vehicle <NUM> may be a hybrid or all electric configuration having electric motors to provide propulsive force for the vehicle. In some configurations the TRU system <NUM> may be engineless. In some embodiments, a small engine or the engine of the vehicle <NUM> may be employed to power or partially power the TRU <NUM>. The container <NUM> may be coupled to the vehicle <NUM> and is thus pulled or propelled to desired destinations. The trailer may include a top wall <NUM>, a bottom wall <NUM> opposed to and spaced from the top wall <NUM>, two side walls <NUM> spaced from and opposed to one-another, and opposing front and rear walls <NUM>, <NUM> with the front wall <NUM> being closest to the vehicle <NUM>. The container <NUM> may further include doors (not shown) at the rear wall <NUM>, or any other wall. The walls <NUM>, <NUM>, <NUM>, <NUM>, <NUM> together define the boundaries of a cargo compartment <NUM>. Typically, transport refrigeration systems <NUM> are 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 TRU <NUM> is associated with a container <NUM> to 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 compartment <NUM>. In further embodiments, the TRU <NUM> is a refrigeration system capable of providing a desired temperature and humidity range.

Referring to <FIG> and <FIG>, the container <NUM> is generally constructed to store a cargo (not shown) in the compartment <NUM>. The TRU <NUM> is generally integrated into the container <NUM> and may be mounted to the front wall <NUM>. The cargo is maintained at a desired temperature by cooling of the compartment <NUM> via the TRU <NUM> that circulates refrigerated airflow into and through the cargo compartment <NUM> of the container <NUM>. It is further contemplated and understood that the TRU <NUM> may be applied to any transport compartments (e.g., shipping or transport containers) and not necessarily those used in tractor trailer systems. Furthermore, the transport container <NUM> may be a part of the of the vehicle <NUM> or constructed to be removed from a framework and wheels (not shown) of the container <NUM> for alternative shipping means (e.g., marine, railroad, flight, and others).

The components of the TRU <NUM> may include a compressor <NUM>, an electric compressor motor <NUM>, a condenser <NUM> that may be air cooled, a condenser fan assembly <NUM>, a receiver <NUM>, a filter dryer <NUM>, a heat exchanger <NUM>, an expansion valve <NUM>, an evaporator <NUM>, an evaporator fan assembly <NUM>, a suction modulation valve <NUM>, and a controller <NUM> that may include a computer-based processor (e.g., microprocessor) and the like as will be described further herein. Operation of the TRU <NUM> may best be understood by starting at the compressor <NUM>, where the suction gas (e.g., natural refrigerant, hydro-fluorocarbon (HFC) R-404a, HFC R-134a. etc.) enters the compressor <NUM> at a suction port <NUM> and is compressed to a higher temperature and pressure. The refrigerant gas is emitted from the compressor <NUM> at an outlet port <NUM> and may then flow into tube(s) <NUM> of the condenser <NUM>.

Air flowing across a plurality of condenser coil fins (not shown) and the tubes <NUM>, cools the gas to its saturation temperature. The air flow across the condenser <NUM> may be facilitated by one or more fans <NUM> of the condenser fan assembly <NUM>. The condenser fans <NUM> may be driven by respective condenser fan motors <NUM> of the fan assembly <NUM> that may be electric. By removing latent heat, the refrigerant gas within the tubes <NUM> condenses to a high pressure and high temperature liquid and flows to the receiver <NUM> that provides storage for excess liquid refrigerant during low temperature operation. From the receiver <NUM>, the liquid refrigerant may pass through a sub-cooler heat exchanger <NUM> of the condenser <NUM>, through the filter-dryer <NUM> that keeps the refrigerant clean and dry, then to the heat exchanger <NUM> that increases the refrigerant sub-cooling, and finally to the expansion valve <NUM>.

As the liquid refrigerant passes through the orifices of the expansion valve <NUM>, some of the liquid vaporizes into a gas (i.e., flash gas). Return air from the refrigerated space (i.e., cargo compartment <NUM>) flows over the heat transfer surface of the evaporator <NUM>. As the refrigerant flows through a plurality of tubes <NUM> of the evaporator <NUM>, 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 assembly <NUM> includes one or more evaporator fans <NUM> that may be driven by respective fan motors <NUM> that may be electric. The air flow across the evaporator <NUM> is facilitated by the evaporator fans <NUM>. From the evaporator <NUM>, the refrigerant, in vapor form, may then flow through the suction modulation valve <NUM>, and back to the compressor <NUM>. The expansion valve <NUM> may be thermostatic or electrically adjustable. In an embodiment, as depicted, the expansion valve <NUM> is thermostatic. A thermostatic expansion valve bulb sensor <NUM> may be located proximate to an outlet of the evaporator tube <NUM>. The bulb sensor <NUM> is intended to control the thermostatic expansion valve <NUM>, thereby controlling refrigerant superheat at an outlet of the evaporator tube <NUM>. 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 (CO<NUM>) refrigerant, and that may be a two-stage vapor compression system. In another embodiment, the expansion valve <NUM> could be an electronic expansion valve. In this case the expansion valve is commanded to a selected position by the controller <NUM> based 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 evaporator <NUM>. This will allow the evaporator coil to be filled with liquid and completely 'wetted' to improve heat transfer efficiency. With CO<NUM> refrigerant, this bypass flash gas may be re-introduced into a mid-stage of a two-stage compressor <NUM>.

The compressor <NUM> and the compressor motor <NUM> may be linked via an interconnecting drive shaft <NUM>. The compressor <NUM>, the compressor motor <NUM> and the drive shaft <NUM> may all be sealed within a common housing <NUM>. The compressor <NUM> may 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 CO<NUM>, propane, ammonia, or any other natural refrigerant that may include a global-warming potential (GWP) of about one (<NUM>).

Continuing with <FIG>, with continued reference to <FIG>. <FIG> also illustrates airflow through the TRU <NUM> and the cargo compartment <NUM>. Airflow is circulated into and through and out of the cargo compartment <NUM> of the container <NUM> by means of the TRU <NUM>. A return airflow <NUM> flows into the TRU <NUM> from the cargo compartment <NUM> through a return air intake <NUM>, and across the evaporator <NUM> via the fan <NUM>, thus conditioning the return airflow <NUM> to a selected or predetermined temperature. The conditioned return airflow <NUM>, now referred to as supply airflow <NUM>, is supplied into the cargo compartment <NUM> of the container <NUM> through the refrigeration unit outlet <NUM>, which in some embodiments is located near the top wall <NUM> of the container <NUM>. The supply airflow <NUM> cools the perishable goods in the cargo compartment <NUM> of the container <NUM>. It is to be appreciated that the TRU <NUM> can further be operated in reverse to warm the container <NUM> when, for example, the outside temperature is very low.

A temperature sensor <NUM> (i.e., thermistor, thermocouples, RTD, and the like) is placed in the air stream, on the evaporator <NUM>, at the return air intake <NUM> , and the like, to monitor the temperature return airflow <NUM> from the cargo compartment <NUM>. A sensor signal indicative of the return airflow temperature denoted RAT is operably connected via line <NUM> to the TRU controller <NUM> to facilitate control and operation of the TRU <NUM>. Likewise, a temperature sensor <NUM> is placed in the supply airflow <NUM>, on the evaporator <NUM>, at the refrigeration unit outlet <NUM> to monitor the temperature of the supply airflow <NUM> directed into the cargo compartment <NUM>. Likewise, a sensor signal indicative of the supply airflow temperature denoted SAT <NUM> is operably connected via line <NUM> to the TRU controller <NUM> to facilitate control and operation of the TRU <NUM>.

Referring now to <FIG>, with continued reference to <FIG> and <FIG> as well, in an example not in accordance with the present invention the TRU <NUM> may include or be operably interfaced with a power supply interface shown generally as <NUM>. The power supply interface <NUM> may include, interfaces to various power sources denoted generally as <NUM> and more specifically as follows herein for the TRU <NUM> and the components thereof. In an embodiment the power sources <NUM> may include, but not be limited to an energy storage device <NUM>, generator <NUM>, and grid power, <NUM>. Each of the power sources <NUM> may be configured to selectively power the TRU <NUM> including compressor motor <NUM>, the condenser fan motors <NUM>, the evaporator fan motors <NUM>, the controller <NUM>, and other components <NUM> of the TRU <NUM> that may include various solenoids and/or sensors). The controller <NUM> through a series of data and command signals over various pathways <NUM> may, for example, control the application of power to the electric motors <NUM>, <NUM>, <NUM> as dictated by the cooling needs of the TRU <NUM>.

The TRU <NUM> may include an AC or DC architecture with selected components employing alternating current (AC), and others employing direct current (DC). For example, the motors <NUM>, <NUM>, <NUM> may be configured as AC motors, while in other examples, the motors <NUM>, <NUM>, <NUM> may be configured as DC motors. The operation of the of the power sources <NUM> as they supply power to the TRU <NUM> may be managed and monitored by power management system <NUM>. The power management system <NUM> is configured to determine a status of various power sources <NUM>, control their operation, and direct the power to and from the various power sources <NUM> and the like based on various requirements of the TRU <NUM>. In an example, the TRU controller <NUM> receives various signals indicative of the operational state of the TRU <NUM> and determines the power requirements for the TRU system <NUM> accordingly and directs the power supply interface <NUM> and specifically the power management system <NUM> to direct power accordingly to address the requirements of the TRU <NUM>. In one example, the TRU system <NUM> is controlled to a temperature setpoint value selected by the user. The TRU controller <NUM> monitors the RAT and optionally the SAT as measured by the temperature sensors <NUM> and <NUM> respectively. The TRU controller <NUM> estimates the power requirements for the TRU <NUM> based on the RAT (among others) and provides commands accordingly to the various components of the power supply interface <NUM> and specifically the power management system <NUM>, energy storage system <NUM>, and generator power converter <NUM> to manage the generation, conversion, and routing of power in the power supply interface <NUM> and TRU system <NUM>. 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., > <NUM> degrees F), then full power (e.g., at a known voltage supply, current demand is known) is needed by the TRU system <NUM>. 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., ~<NUM>% power or something less than <NUM>%). If the (RAT-setpoint value) is below second threshold, current is limited (at voltage) to achieve a minimum power (e.g., ~<NUM>% power).

The TRU controller <NUM> is configured to control the components in the TRU <NUM> as well as the components of the power supply interface <NUM> in accordance with operating needs of the transport refrigeration system <NUM>. The TRU controller <NUM> is communicatively coupled to the power management system <NUM>, DC/AC converter <NUM>, battery management system <NUM> and the generator power converter <NUM> components of voltage regulator <NUM>, current control circuit <NUM>, frequency converter <NUM> and the generator <NUM>. For the TRU power demand, the TRU controller <NUM>, using additional information from the BMS <NUM> and generator <NUM>, provide instructions to affect the generator output to the power form required by the TRU <NUM>. Additionally, the TRU controller <NUM> provides instructions to manage the power flow via the power management system <NUM> depending upon the operational status of the various power sources (i.e. grid power <NUM>, energy storage device <NUM> and generator <NUM>) as coupled with the TRU <NUM> power demand.

As described further herein, there are three power sources <NUM> - grid power <NUM>, generator <NUM>/generator power converter <NUM> and energy storage device <NUM>. If the TRU <NUM> is "On" and operating, the TRU controller <NUM> knows, the power requirements for the TRU system, and thereby, what power is needed. The TRU controller <NUM> is also programmed to ascertain whether or not grid power (e.g., <NUM>) is available or not. If the grid power is available and TRU is On and energy storage device <NUM> (e.g., battery) SOC indicates a full charge, grid power will satisfy TRU system <NUM> power demand. Conversely, if grid power <NUM> is available and TRU On and the energy storage device is not fully charged, TRU power demand is satisfied as first priority and then DC/AC inverter <NUM> is be activated to provide necessary charging to energy storage device <NUM> as second priority. Moreover, if grid power <NUM> is available and TRU is "Off" and the energy storage device <NUM> is not fully charged, the DC/AC inverter <NUM> will be activated to provide necessary charging current. If grid power <NUM> is not available and generator/generator power converter <NUM>/<NUM> is not operable, all TRU power demand is satisfied by the energy storage system <NUM> via the energy storage device. Finally, if grid power <NUM> is not available and generator/generator power converter <NUM>/<NUM> is operable, then TRU power demand is satisfied by both the generator <NUM> & energy storage system <NUM>.

The power management system <NUM> receives power from a generator <NUM> directly and/or via a generator power converter <NUM>. In an embodiment, the power management system <NUM> may be may be a stand-alone unit, integral with the generator power converter <NUM>, and/or integral with the TRU <NUM>. The generator <NUM> can be axle or hub mounted configured to recover rotational energy when the transport refrigeration system <NUM> is in motion and convert that rotational energy to electrical energy, such as, for example, when the axle of the vehicle <NUM> is rotating due to acceleration, cruising, or braking. In an example, the generator <NUM> is configured to provide a first three phase AC power <NUM> comprising voltage V<NUM>, an AC current I<NUM> at a given frequency f<NUM> denoted by reference numeral <NUM>. The generator <NUM> may be asynchronous or synchronous. In another example, the generator <NUM> may be DC, providing a first DC power 163a including a DC voltage and DC current denoted as V1a, and DC current I1a. The generator power converter <NUM> in one or more embodiments generates a second three phase AC power <NUM> including AC voltage V<NUM>, a second AC current I<NUM> at a selected frequency f<NUM> and is transmitted from the generator power converter <NUM> to the power management system <NUM> or otherwise as described herein.

As described herein, in operation, the TRU controller <NUM> identified the power requirements for the TRU <NUM> at least partially based on the RAT. The TRU controller <NUM> conveys the power requirements to the power management system <NUM> and/or the generator power converter <NUM> to convert the first three phase AC power <NUM> or first DC power 163a to the second three phase AC power <NUM> as necessary to satisfy the requirements of the TRU <NUM>.

In an example, the generator power converter <NUM> is an AC/AC converter and configured to receive the three phase AC power <NUM> (e.g., at AC voltage V<NUM>, AC current I<NUM> a frequency f<NUM>), from the generator <NUM> and convert it to a second three phase AC power denoted <NUM> comprising the second three phase AC voltage V<NUM>, a second AC current I<NUM> at a selected frequency f<NUM>. The second three phase AC power <NUM> is transmitted from the generator power converter <NUM> to the power management system <NUM>. The generator power converter <NUM> is configured to provide the second three phase AC power <NUM> based of the operating requirements of the TRU <NUM>. In an example, the generator power converter <NUM> includes a voltage control function <NUM>, a current control function <NUM>, and frequency converter function <NUM>, each configured to facilitate the conversion. In one or more examples, the TRU controller <NUM> provides command signals denoted <NUM>, <NUM>, and <NUM> to a voltage control function <NUM>, current control function <NUM>, and frequency converter function <NUM> respectively. The command signals <NUM>, <NUM>, and <NUM> are generated by the TRU controller <NUM> based on the power consumption requirements of the TRU <NUM> as discussed further herein. In addition, the TRU controller <NUM> may receive status information as depicted by <NUM> regarding the generator <NUM>, generator power converter <NUM>, or the power management system <NUM> for mode selection and diagnostic purposes. The generator power converter <NUM> may be a stand-alone unit configured to be in close proximity to or even integral with the generator <NUM>. In another example, the generator power converter <NUM> may be integral with the power management system <NUM> and/or the TRU <NUM>.

Continuing with <FIG> and the generator power converter <NUM>, in an example, the voltage control function <NUM> includes a voltage regulation function and is configured to monitor the output voltage from the generator <NUM> and maintains a constant voltage out of the voltage control function <NUM>. The voltage control function <NUM> communicates status to the TRU Controller <NUM>. The current control function <NUM> monitors and communicates to the TRU <NUM> the status of current draw from the generator <NUM>. The current may be limited depending on the power demands of the TRU <NUM>. Finally, the frequency converter function <NUM> monitors the frequency of the three phase power <NUM> produced by the generator <NUM> and converts the three phase power <NUM> to the three phase power <NUM> exhibiting the desired frequency as determined by the voltage control function <NUM> and the TRU controller <NUM>, for supply to the power management system <NUM> and ultimately the TRU <NUM>. In an embodiment the communications may be over standard communication interfaces such as CAN, RS-<NUM>, and the like. Moreover, as is discussed further herein, the communications may be wired or wireless.

In another example, for example, when the generator <NUM> is a DC generator, the generator power converter <NUM> is an DC/AC converter and configured to receive DC power 163a (e.g., at DC voltage V1a, DC current I1a), from the generator <NUM> and convert it to the second three phase AC power <NUM> comprising a second three phase AC voltage V<NUM>, a second AC current I<NUM> at a selected frequency f<NUM>. The second three phase AC power <NUM> is transmitted from the generator power converter <NUM> to the power management system <NUM> as described herein. Once again, as described above, the generator power converter <NUM> is configured to provide the second three phase AC power <NUM> based of the requirements of the TRU <NUM> as described above. In this example, the generator power converter <NUM> including the voltage control function <NUM>, the current control function <NUM>, and frequency converter function <NUM>, are ach configured to facilitate the DC/AC conversion. In this example, once again the TRU controller <NUM> provides command signals denoted <NUM>, <NUM>, and <NUM> to a voltage control function <NUM>, current control function <NUM>, and frequency converter function <NUM> respectively, based on the power consumption requirements of the TRU <NUM> as discussed further herein. In this embodiment, the voltage control function <NUM> includes a voltage regulation function and is configured to monitor the output DC voltage from the generator <NUM> and maintains a constant AC voltage out of the voltage control function <NUM>. The current control function <NUM> monitors and communicates to the TRU <NUM> the status of current draw from the generator <NUM>. Finally, the frequency converter function <NUM> monitors the frequency of the three phase power <NUM> produced by the generator converter <NUM> to ensure it exhibits the desired frequency as determined by the voltage control function <NUM> and the TRU controller <NUM>, for supply to the power management system <NUM> and ultimately the TRU <NUM>.

Continuing with <FIG> and the architecture of the power supply interface <NUM> and the various power sources <NUM> employed to power the TRU <NUM> and the components thereof. In an example, one of the power sources <NUM> may include an energy storage system <NUM> operably coupled to the power management system <NUM>. As described herein, another power source <NUM> that the power management system <NUM> receives power from is the generator <NUM>, whether directly and/or via a generator power converter <NUM>. Furthermore, the grid power source <NUM> provides three phase AC power to the power management system <NUM> under selected conditions. The energy storage system <NUM> transmits three phase power <NUM> to and receives power from the power management system <NUM>. The energy storage system <NUM> may include, but not be limited to the energy storage device <NUM>, and AC/DC converter <NUM> and a battery management system <NUM>. In one example, the power management system <NUM> provides three phase AC power <NUM> to an AC/DC converter <NUM> to formulate a DC voltage and current to charge and store energy on the energy storage device <NUM>. Conversely, in other examples the energy storage device <NUM> supplies DC voltage and current to the AC/DC converter <NUM> operating as a DC/AC converter to supply a three phase AC power <NUM> for powering the TRU <NUM>.

The battery management system <NUM> monitors the performance of the energy storage device <NUM>. For example, monitoring the state of charge of the energy storage device <NUM>, a state of health of the energy storage device <NUM>, and a temperature of the energy storage device <NUM>. Examples of the energy storage device <NUM> may include a battery system (e.g., a battery or bank of batteries), fuel cells, flow battery, and others devices capable of storing and outputting electric energy that may be direct current (DC). The energy storage device <NUM> may include a battery system, which may employ multiple batteries organized into battery banks through which cooling air may flow for battery temperature control, as described in <CIT>.

If the energy storage system <NUM> includes a battery system for the energy storage device <NUM>, 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, the higher the voltage, the greater is the size and weight of, for example, batteries in an energy storage device <NUM>, which is not preferred when transporting cargo. Additionally, if the energy storage device <NUM> is 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 device <NUM> will require more batteries in series than lower voltages, which in turn results in bigger and heavier battery energy storage device <NUM>. A lower voltage and higher current system may be used, however such a system may require larger cabling or bus bars. In one example, the energy storage device <NUM> may be contained within the structure <NUM> of the TRU <NUM>. In an embodiment, the energy storage device <NUM> is located with the TRU <NUM>, however, other configurations are possible. In another embodiment, the energy storage device <NUM> may be located with the container <NUM> such as, for example, underneath the cargo compartment <NUM>. Likewise, the AC/DC converter <NUM> may be located with the container <NUM> such as, for example, underneath the cargo compartment <NUM>, however, in some examples it may be desirable to have the AC/DC converter <NUM> in close proximity to the power management system <NUM> and/or the TRU <NUM> and TRU controller <NUM>. It will be appreciated that in one or more examples, while particular locations are described with respect to connection and placement of selected components including the energy storage device <NUM> and/or AC/DC converter <NUM>, such descriptions are merely illustrative. Varied location, arrangement and configuration of components is possible.

The battery management system <NUM> and AC/DC converter <NUM> are operably connected to and interface with the TRU controller <NUM>. The TRU controller <NUM> receives information regarding the status of energy storage system <NUM>, including the energy storage device <NUM> to provide control inputs to the AC/DC converter <NUM> to monitor the energy storage device <NUM>, control charge and discharge rates for the energy storage device <NUM> and the like.

Continuing with <FIG>, as described earlier, the power supply interface <NUM> may include, interfaces to various power sources <NUM> managed and monitored by power management system <NUM>. The power management system <NUM> manages and determines electrical power flows in the power supply interface <NUM> based upon the operational needs of the TRU <NUM> and the capabilities of the components in the power supply interface <NUM>, (e.g., generator <NUM>, converter <NUM>, energy storage device <NUM>, and the like. The power management system <NUM> is configured to determine a status of various power sources <NUM>, control their operation, and direct the power to and from the various power sources <NUM> and the like based on various requirements of the TRU <NUM>.

In an example there are five primary power flows managed by the power management system <NUM>. First, the power into the power management system <NUM> supplied via the generator <NUM> or generator power converter <NUM>, e.g., second three phase AC power <NUM>). Second, the power supplied to the power management system <NUM> when the TRU system <NUM> is operably connected to grid power source <NUM>. Third the power supplied to the power management system <NUM> from an energy storage device <NUM>. Fourth, the power directed from the power management system <NUM> to the energy storage device <NUM>. Finally, the power directed to the TRU <NUM> from the power management system <NUM> for providing power to operate the TRU <NUM>.

The power flows will be transferred through different paths based on the requirements placed on the power management system <NUM> and particular configuration of the power supply interface <NUM>. The power management system <NUM> operates as a central power bus to connect various power sources <NUM> together to supply the power needs of the TRU <NUM>. The power management system <NUM> controls switching, directing, or redirecting power to/from the five power flows as needed to satisfy the power requirements of the TRU <NUM>. Switching, directing, and redirecting may readily be accomplished by employing a bus control switching device <NUM> of the power management system <NUM>. The bus control switching device <NUM> may include electromechanical and solid state semiconductor switching devices including relays, contactors, solid state contactors as well as semiconductor switching devices such as transistors, FETs, MOSFETS, IGBT's, thyristors, SCR's, and the like. In addition, to facilitate and implement the functionality of the power management system <NUM>, the voltages and frequencies of the power whether supplied by the grid power supply <NUM>, generator <NUM>, generator converter <NUM>, or the AC/DC converter <NUM> of the energy storage system <NUM> need to be synchronized to provide a common power source to be supplied to the TRU <NUM> and/or charge the energy storage device <NUM>. Current draw will be determined by the TRU <NUM> and the need to charge the energy storage device <NUM>.

The generator power converter <NUM> output (the second three phase AC power <NUM>) and/or grid power from the grid power source <NUM> and/or power directed to/from the energy storage system <NUM> is supplied to the bus control switching device <NUM> in an overlapping or break-before-make condition as determined by the bus control switching device <NUM> of the power management system. The AC/DC converter <NUM>, when operating as a DC to AC converter synchronizes the voltage and frequency of the three phase power (e.g., <NUM>) generated via the energy storage system <NUM> with the power connected bus control switching device <NUM> in order to transfer power from the energy storage device <NUM> to the power management system <NUM> (an thereby the TRU <NUM>) as needed. Likewise, grid power from the grid power source <NUM> provided to the power management system <NUM> is directed by the bus control switching device <NUM> once connected and the AC/DC converter <NUM> monitor the bus voltage and frequency to determine if the above parameters are equal before connectivity is permitted. This will allow minimum disruption of the power bus system. In other words, anytime two or more power sources are available, the bus control switching device, and the AC/DC convert <NUM> ensure that power is matched and synchronized to enable connectivity. The power bus control device <NUM> communicates to the TRU controller <NUM> to determine status of flows connected. In an embodiment, the power management system <NUM>, and or the TRU controller <NUM> provides visual indications of which source (e.g., grid power source <NUM>, generator <NUM> or energy storage system <NUM>) is selected and operating on the bus control switching device <NUM>.

Turning now to <FIG> each providing a simplified diagram depicting each of the eight identified power flows combinations. <FIG> depict power flows for power supplied from the generator <NUM> and/or generator power converter <NUM> (e.g., second three phase AC power). Referring now to <FIG>, in an embodiment, the logic employed by the TRU controller <NUM> for directing the power in the power management system <NUM> determines if the TRU <NUM> is operating. If so, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a charge state that is less than a selected threshold, then the power management system <NUM> directs power to both the TRU <NUM> and the energy storage system <NUM> for recharging the energy storage device <NUM>. In an embodiment, priority is given to satisfying the power requirements of the TRU <NUM>. Any remaining power may be directed to the recharging application for the energy storage system <NUM>. It should be appreciated that while particular threshold of <NUM>% 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 to <FIG> as well, the figure depicts a second instance for power flows for power supplied from the generator <NUM> and/or generator power converter <NUM>. In this embodiment, if the TRU <NUM> is operating, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a state of charge that is in excess of a selected threshold, then the power management system <NUM> directs power to only the TRU <NUM>, (as the and the energy storage system <NUM> does not yet require recharging). Similarly, in yet another embodiment, as depicted by <FIG>, a third power flow governed by the power management system <NUM> for power supplied from the generator <NUM> and/or generator power converter <NUM>. In this embodiment, the logic employed by the TRU controller <NUM> for directing the power in the power management system <NUM> addresses an instance when the TRU <NUM> is inoperative, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a state of charge that is less than a selected threshold (in this instance <NUM>%, though other thresholds are possible). In this embodiment, the power management system <NUM> directs power to only to the energy storage system <NUM> for recharging the energy storage device <NUM>. In an embodiment, priority is given to satisfying the power requirements of energy storage system <NUM> and secondarily to providing power to the TRU <NUM>.

Turning now to <FIG>, which depict power flows for power supplied from the grid power source <NUM>. In an embodiment as depicted in <FIG>, the logic employed by the TRU controller <NUM> for directing the power from the grid power source <NUM> in the power management system <NUM> determines if the TRU <NUM> is operating and the generator <NUM> (or the generator power converter <NUM>) is inoperative. If so, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a charge state that is less than a selected threshold, then the power management system <NUM> directs power to both the TRU <NUM> and the energy storage system <NUM> for recharging the energy storage device <NUM>. In an embodiment, once again, priority is given to satisfying the power requirements of the TRU <NUM>. Any remaining power may be directed to the recharging application for the energy storage system <NUM>. It should be appreciated that while particular threshold of <NUM>% 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 to <FIG> as well, the figure depicts a second instance for power flows for power supplied from the grid power source <NUM> when the generator <NUM> is inoperative. In this embodiment, if the TRU <NUM> is operating, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a state of charge that is in excess of a selected threshold, then the power management system directs power to only the TRU <NUM>, (as the energy storage system <NUM> does not yet require recharging). Similarly, in yet another embodiment, as depicted by <FIG>, a third power flow governed by the power management system <NUM> for power supplied from the grid power source <NUM> when the generator <NUM> is inoperative. In this embodiment, the logic employed by the TRU controller <NUM> for directing the power in the power management system <NUM> addresses an instance when the TRU <NUM> is also inoperative, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a state of charge that is less than a selected threshold (in this instance <NUM>%, though other thresholds are possible). In this embodiment, the power management system <NUM> directs power to only to the energy storage system <NUM> for recharging the energy storage device <NUM>. In an embodiment, priority is given to satisfying the power requirements of energy storage system <NUM>.

Turning now <FIG>, which depict power flows for power supplied to the TRU <NUM> under selected conditions for operating from the energy storage system <NUM> as well. In <FIG> power flows to the TRU <NUM> are provided from the generator <NUM> and/or generator power converter <NUM> (e.g., second three phase AC power <NUM>) as well as from the energy storage system <NUM>. In an embodiment, the logic employed by the TRU controller <NUM> for directing the power in the power management system <NUM> determines if the TRU <NUM> is operating. If so, and the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a charge state of greater than a selected threshold, then the power management system <NUM> directs power from both the generator <NUM> (or generator power converter <NUM>) and the energy storage system <NUM> is directed to the TRU <NUM>. In an embodiment a threshold of <NUM> percent is employed for the state of charge of the energy storage device <NUM>. In this embodiment, power is provided by the energy storage system <NUM> and thereby discharging the energy storage device <NUM>. In an embodiment, priority is given to satisfying the power requirements of the TRU <NUM>. This embodiment may be employed under conditions where the output power of the generator <NUM> and/or generator power converter <NUM> is less that that needed to operate the TRU <NUM>. It should be appreciated that while particular threshold of <NUM>% 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 TRU <NUM> such that fully draining the energy storage device <NUM> is acceptable. Likewise, in other embodiments, it may be desirable to modify the function or curtail the operation of the TRU <NUM> to avoid excessively discharging the energy storage device <NUM>.

Referring now to <FIG> as well, the figure depicts a second instance for power flows from the energy storage system <NUM> alone. In this embodiment, if the TRU <NUM> is operating, but the generator <NUM> and/or the generator power converter <NUM> is inoperative, if the energy storage system <NUM> indicates that the energy storage device <NUM> is exhibiting a state of charge that is in excess of a selected threshold, then the power management system <NUM> directs power to the TRU <NUM>. In an embodiment a threshold of <NUM> percent is employed for the state of charge of the energy storage device <NUM>. In this embodiment, power is provided by the energy storage system <NUM> and thereby discharging the energy storage device <NUM>. In an embodiment, priority is given to satisfying the power requirements of the TRU <NUM>. Once again, this embodiment may be employed under conditions where the output power of the generator <NUM> and/or generator power converter <NUM> is less that that needed to operate the TRU <NUM>. It should be appreciated that while particular threshold of <NUM>% 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 TRU <NUM> such that fully draining the energy storage device <NUM> is 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 device <NUM>.

In another embodiment and specialized mode of operation and power flow for the TRU system <NUM> and the power supply interface <NUM>. In this embodiment, referred to as a fail operational or "limp home" mode, the power supply interface <NUM> is configured such that, in selected modes of operation power is directed to the TRU <NUM> from the tractor or vehicle <NUM>. In an embodiment, should the energy storage device <NUM> exhibit a SOC below a selected threshold e.g., <<NUM>% and the generator <NUM>/generator power converter <NUM> is not operable but the TRU system <NUM> is 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 generator <NUM> being installed on the trailer portion of the vehicle, <NUM>, such description is merely illustrative. In another embodiment, the generator <NUM> or another generator could be installed at a hub or axle of the tractor portion of the vehicle <NUM> without 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 management system through a grid plug <NUM>. Alternately connectable between the grid power source <NUM> and the vehicle power. For example, in operation, when vehicle <NUM> trailer is in operation, for example, on delivery, grid plug <NUM> would be plugged into the tractor/trailer's electric PTO and act as mobile grid source. The TRU controller <NUM> would 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 system <NUM>.

Turning now to <FIG>, depicted therein is an embodiment of the present invention, and one example not in accordance with the present invention, of the architecture of the power supply interface, in these instances, denoted <NUM>, and the various power sources <NUM> employed to power the TRU <NUM>. In an embodiment, the power sources <NUM> may include, but not be limited to an energy storage system <NUM> operably coupled to the power management system <NUM> and the grid power source <NUM>. Moreover, as described above, the generator <NUM>, whether directly and/or via a generator power converter <NUM> is operably connected to the energy storage system <NUM>, and more specifically to the energy storage device <NUM>. In the embodiment of the present invention the generator <NUM> is an AC generator <NUM>, the generator power converter <NUM> is an AC/DC converter and configured to receive three phase AC power <NUM> (e.g., at AC voltage V<NUM>, AC current I<NUM> and frequency f<NUM>), from the generator <NUM> and convert it to the third DC power denoted 165b comprising a DC voltage V<NUM>, a third DC current I<NUM>. In the example not in accordance with the present invention, when the generator <NUM> is a DC generator (denoted in the figures as 162a, the generator power converter, denoted as 164a is a DC/DC converter and configured to receive DC power denoted 163a (e.g., at DC voltage V1a, DC current I1a), from the generator 162a and convert it to the third DC power denoted 165b comprising a DC voltage V<NUM>, a third DC current I<NUM>.

In each of the embodiment and the example, the third DC power 165b is transmitted from the generator power converter <NUM> (or 164a) directly to the energy storage system <NUM>. Once again, as described herein, the generator power converter <NUM>, 164a is configured to provide the third DC power 165b based of the requirements of the TRU <NUM> as described above. The generator power converter <NUM>, 164a including the voltage control function <NUM> (see for example, <FIG>), the current control function <NUM> (<FIG>), is configured to facilitate the AC/DC conversion for generator power converter <NUM>, and likewise the DC/DC conversion for generator power converter 164a in the example. Once again the TRU controller <NUM> provides command signals denoted <NUM>, 169a to the voltage control function <NUM>, and/or current control function <NUM> respectively, based on the power consumption requirements of the TRU <NUM> as discussed further herein. As described previously, the voltage control function <NUM> includes a voltage regulation function and is configured to monitor the output AC or DC voltage from the generator <NUM> and maintains a constant DC voltage out of the voltage control function <NUM> for supply to the energy storage system <NUM> and the energy storage device <NUM>. The current control function <NUM> monitors and communicates to the TRU <NUM> the status of current draw from the generator <NUM>, 162a. Once again, the status of the generator <NUM>, 162a is monitored by the TRU controller <NUM> via line <NUM>, 172a.

Continuing with <FIG> and an embodiment and an example of the architecture of the <NUM> power supply interface <NUM> and the various power sources <NUM> employed to power the TRU <NUM> and the components thereof. As described above, the generator <NUM>, 162a whether directly and/or via a generator power converter <NUM> is operably connected to the energy storage system <NUM>. In an embodiment, the energy storage device <NUM>, includes eletrical switching device <NUM> controllable by the TRU controller and/or BMS <NUM> employed as a DC power manager. The electrical switching device <NUM> is configured to connect power flows of the generator162/generator power converter <NUM>, 164a, and battery of the energy storage device <NUM> to feed DC power <NUM> as needed to the DC/AC converter <NUM> and to the power management system <NUM> to satisfy TRU demand. Through this circuitry, the TRU demand will be satisfied by either all power from the generator <NUM>/generator converter <NUM>, 164a, all power from the battery or some combination of power from generator <NUM>/generator converter <NUM>, 164a and the battery. For example, if the TRU power demand is less than the generator power available, TRU power requirements are met with power from the generator <NUM>/generator converter <NUM>, 164a and any remaining generator power is directed to charge the battery of the energy storage device. Control of the electrical circuitry (through BMS <NUM>) will manage flow into and out of battery and meet TRU demand as needed.

Continuing with the energy storage system, and more specifically to the energy storage device <NUM>, the energy storage system <NUM> transmits power to and receives power from the power management system <NUM> via the AC/DC converter <NUM> operating as a DC/AC converter. Once again, the energy storage system <NUM> includes the energy storage device <NUM>, and AC/DC converter <NUM> and a battery management system <NUM>. In one embodiment and one example, when operating from grid power source <NUM>, the power management system <NUM> provides three phase AC power to the TRU <NUM> as described with the power flows above. In addition, as needed, to maintain sufficient charge on the energy storage device <NUM>, the power management system <NUM> may also direct three phase AC power to the AC/DC converter <NUM> to formulate a DC voltage and current to charge and store energy on the energy storage device <NUM>. Conversely, when the grid power source <NUM> is not available, the energy storage device <NUM> supplies DC voltage and current to the AC/DC converter <NUM> operating as a DC/AC converter to supply a three phase AC voltage and current to the power management system <NUM> for powering the TRU <NUM>. Once again, the TRU <NUM> may be operated from the energy storage system <NUM> provided the state of charge of the energy storage device <NUM> exceeds a selected threshold. The selected threshold may be <NUM>% state of charge. Once again, as described herein, the battery management system <NUM> monitors the perfomance of the energy storage device <NUM>. For example, monitoring the state of charge of the energy storage device <NUM>, a state of health of the energy storage device <NUM>, and a temperature of the energy storage device <NUM>. The battery management system <NUM> and AC/DC converter <NUM> are operably connected to and interface with the TRU controller <NUM>. The TRU controller <NUM> receives information regarding the status of energy storage system <NUM>, including the energy storage device <NUM> to provide control inputs to the AC/DC converter <NUM> to monitor the energy storage device, <NUM>, control charge and discharge rates for the energy storage device <NUM> and the like.

As described herein, examples of the energy storage device <NUM> may include a battery system (e.g., a battery or bank of batteries), fuel cells, and others devices capable of storing and outputting electric energy that may be direct current (DC). If the energy storage system <NUM> includes a battery system for the energy storage device <NUM>, the battery system may have a voltage potential within a range of about two-hundred volts (200V) to about six-hundred volts (600V). The energy storage device <NUM> may be contained within the structure <NUM> of the TRU <NUM>. The energy storage device <NUM> may be located with the TRU <NUM>, however other configurations are possible. The energy storage device <NUM> may be located with the container <NUM> such as, for example, underneath the cargo compartment <NUM>. Likewise, the AC/DC converter <NUM> may be located with the container <NUM> such as, for example, underneath the cargo compartment <NUM>, however, in some embodiments it may be desirable to have the AC/DC converter <NUM> in close proximity to the power management system <NUM> and/or the TRU <NUM> and TRU controller <NUM>. It will be appreciated that, while particular locations are described with respect to connection and placement of selected components including the energy storage device <NUM> and/or AC/DC converter <NUM>, such descriptions are merely illustrative and are not intended to be limiting. Varied location, arrangement and configuration of components is possible.

Continuing with <FIG>, as described earlier, the power supply interface <NUM> may include, interfaces to various power sources <NUM> managed and monitored by power management system <NUM>. The power management system <NUM> manages and determines electrical power flows in the power supply interface <NUM> based upon the operational needs of the TRU <NUM> and the capabilities of the components in the power supply interface <NUM>, (e.g., generator <NUM>, 162a, generator power converter <NUM>, 164a, energy storage device <NUM>, grid power source <NUM>, and the like. The power management system <NUM> is configured to determine a status of various power sources <NUM>, control their operation, and direct the power to and/or from the various power sources <NUM> and the like, based on various operational requirements of the TRU <NUM>. In an embodiment, the TRU controller <NUM> receives various signals indicative of the operational state of the TRU <NUM> and determines the power requirements for the TRU system <NUM> accordingly and directs the power supply interface <NUM> and specifically the power management system <NUM> to direct power accordingly to address the requirements of the TRU <NUM>. In one embodiment, the TRU controller <NUM> monitors the RAT and optionally the SAT as measured by the temperature sensors <NUM> and <NUM> respectively. The TRU controller <NUM> estimates the power requirements for the TRU <NUM> based on the RAT (among others) and provides commands accordingly to the various components of the power supply interface <NUM> and specifically the power management system <NUM>, energy storage system <NUM>, and generator power converter <NUM> to manage the generation, conversion, and routing of power in the power supply interface <NUM> and TRU system <NUM>.

Turning now to <FIG>, depicted therein is one embodiment of the present invention and one example not in accordance with the present invention of the architecture of the power supply interface, in these instances, denoted <NUM>, and the various power sources <NUM> employed to power the TRU <NUM>. The power sources <NUM> may include to an energy storage system <NUM> operably coupled to the power management system 124a, which is similar to the power management system <NUM> of the earlier embodiments, but including additional functions and features, and the grid power source <NUM>. Moreover, as described above, the generator <NUM>, whether directly and/or via a generator power converter <NUM> is operably connected to the energy storage system <NUM>, and more specifically to the energy storage device <NUM>. In the embodiment of to the present invention, the generator <NUM> is an AC generator <NUM>, the generator power converter <NUM> is an AC/DC converter and configured to receive three phase AC power <NUM> (e.g., at AC voltage V<NUM>, AC current I<NUM> and frequency f<NUM>), from the generator <NUM> and convert it to the third DC power denoted 165b comprising a DC voltage V<NUM>, a third DC current I<NUM>. Alternatively, in the example not in accordance with the present invention, the generator <NUM> is a DC generator denoted in the figures as 162a, the generator power converter, denoted as 164a is a DC/DC converter and configured to receive DC power denoted 163a (e.g., at DC voltage V1a, DC current I1a), from the generator 162a and convert it to the third DC power denoted 165b comprising a DC voltage V<NUM>, a third DC current I<NUM>.

In each of the embodiment and the example, the third DC power 165b is transmitted from the generator power converter <NUM> (or 164a) directly to the energy storage system <NUM>. Once again, as described herein, the generator power converter <NUM>, 164a is configured to provide the third DC power 165b based of the requirements of the TRU <NUM> as described above. The generator power converter <NUM>, 164a including the voltage control function <NUM> (see for example, <FIG>), the current control function <NUM> (<FIG>), is configured to facilitate the AC/DC conversion for generator power converter <NUM>, and likewise the DC/DC conversion for generator power converter 164a of an alternative embodiment. Once again the TRU controller <NUM> provides command signals denoted <NUM>, 169a to the voltage control function <NUM>, and/or current control function <NUM> respectively, based on the power consumption requirements of the TRU <NUM> as discussed further herein. As described previously, the voltage control function <NUM> includes a voltage regulation function and is configured to monitor the output AC or DC voltage from the generator <NUM> and maintains a constant DC voltage out of the voltage control function <NUM> for supply to the energy storage system <NUM> and the energy storage device <NUM>. The current control function <NUM> monitors and communicates to the TRU <NUM> the status of current draw from the generator <NUM>, 162a. Once again, the status of the generator <NUM>, 162a is monitored by the TRU controller 82via line <NUM>, 172a.

Continuing with <FIG> and an embodiment and an example of the architecture of the <NUM> power supply interface <NUM> and the various power sources <NUM> employed to power the TRU <NUM> and the components thereof. As described above, the generator <NUM>, 162a whether directly and/or via a generator power converter <NUM> is operably connected to the energy storage system <NUM>. The energy storage device <NUM>, includes electrical switching device <NUM> controllable by the TRU controller and/or BMS <NUM> employed as a DC power manager. The electrical switching device <NUM> is configured to connect power flows of the generator162/generator power converter <NUM>, 164a, and battery of the energy storage device <NUM> to feed DC power <NUM> as needed to the DC/AC converter <NUM> and to the power management system <NUM> to satisfy TRU demand. Through this circuitry, the TRU demand will be satisfied by either all power from the generator <NUM>/generator converter <NUM>, 164a, all power from the battery or some combination of power from generator <NUM>/generator converter <NUM>,164a and the battery. For example, if the TRU power demand is less than the generator power available, TRU power requirements are met with power from the generator <NUM>/generator converter <NUM>,164a and any remaining generator power is directed to charge the battery of the energy storage device. Control of the electrical circuitry (through BMS <NUM>) will manage flow into and out of battery and meet TRU demand as needed.

Continuing with <FIG> and an embodiment and an example of the architecture of the power supply interface <NUM> and the various power sources <NUM> employed to power the TRU <NUM> and the components thereof. As described above, the generator <NUM>, 162a whether directly and/or via a generator power converter <NUM> is operably connected to the energy storage system <NUM>, and more specifically to the energy storage device <NUM>. The energy storage system <NUM> transmits power to and receives power from the power management system 124a. Once again, the energy storage system <NUM> includes the energy storage device <NUM>, and AC/DC converter <NUM> and a battery management system <NUM>. When operating from grid power source <NUM>, the power management system 124a provides three phase AC power to the TRU <NUM> as described with the power flows above. In addition, as needed, to maintain sufficient charge on the energy storage device <NUM>, the power management system 124a may also direct three phase AC power to the AC/DC converter <NUM> to formulate a DC voltage and current to charge and store energy on the energy storage device <NUM>. Conversely, when the grid power source <NUM> is not available, the energy storage device <NUM> supplies DC voltage and current to the AC/DC converter <NUM> operating as a DC/AC converter to supply a three phase AC voltage and current to the power management system <NUM> for powering the TRU <NUM>. Once again, the TRU <NUM> may be operated from the energy storage system <NUM> provided the state of charge of the energy storage device <NUM> exceeds a selected threshold. The selected threshold may be <NUM>% state of charge. Once again, as described herein, the battery management system <NUM> monitors the performance of the energy storage device <NUM>. For example, monitoring the state of charge of the energy storage device <NUM>, a state of health of the energy storage device <NUM>, and a temperature of the energy storage device <NUM>. The battery management system <NUM> and AC/DC converter <NUM> are operably connected to and interface with the TRU controller <NUM>. The TRU controller <NUM> receives information regarding the status of energy storage system <NUM>, including the energy storage device <NUM> to provide control inputs to the AC/DC converter <NUM> to monitor the energy storage device, <NUM>, control charge and discharge rates for the energy storage device <NUM> and the like.

As described previously with respect to the various embodiments and examples herein, examples of the energy storage device <NUM> may include a battery system (e.g., a battery or bank of batteries), fuel cells, and others devices capable of storing and outputting electric energy that may be direct current (DC) as discussed herein.

Continuing with <FIG>, as described earlier, the power supply interface <NUM> may include, interfaces to various power sources <NUM> managed and monitored by power management system 124a. The power management system <NUM> manages and determines electrical power flows in the power supply interface <NUM> based upon the operational needs of the TRU <NUM> and the capabilities of the components in the power supply interface <NUM>, (e.g., generator <NUM>, 162a, generator power converter <NUM>, 164a, energy storage device <NUM>, grid power source <NUM>, and the like. The power management system 124a is configured to determine a status of various power sources <NUM>, control their operation, and direct the power to and/or from the various power sources <NUM> and the like, based on various operational requirements of the TRU <NUM>. Moreover, the power management system 124a may also include an AC/DC converter <NUM> configured to receive the incoming three phase AC voltage <NUM> and convert a portion thereof to a DC voltage <NUM> to facilitate maintenance, configuration and operation of the TRU <NUM>. The addition of AC/DC converter <NUM> eliminates the need for a separate TRU battery to maintain operation of the TRU controller <NUM>. Moreover, the DC voltage generated by the AC/DC converter <NUM> is also employed to power selected sensors and components of the TRU system <NUM>. Advantageously, generating the needed low voltage DC power in the power management systems simplifies the wiring and routing of the TRU system <NUM> and power supply interface <NUM> by eliminating an additional set of DC cabling from the energy storage device <NUM> beyond the cabling going to the AC/DC converter <NUM>. Otherwise, the power management system 124a, would require two sets of DC cabling (a high voltage set directed to the AC/DC converter <NUM>, and a low voltage set optionally directed to the TRU directly) out of energy storage device vs. only the single DC cabling in the described embodiments.

The TRU controller <NUM> receives various signals indicative of the operational state of the TRU <NUM> and determines the power requirements for the TRU system <NUM> accordingly and directs the power supply interface <NUM> and specifically the power management system 124a to direct power accordingly to address the requirements of the TRU <NUM>. The TRU controller <NUM> can monitor the RAT and optionally the SAT as measured by the temperature sensors <NUM> and <NUM> respectively. The TRU controller <NUM> estimates the power requirements for the TRU <NUM> based on the RAT (among others) and provides commands accordingly to the various components of the power supply interface <NUM> and specifically the power management system <NUM>, energy storage system <NUM>, and generator power converter <NUM> to manage the generation, conversion, and routing of power in the power supply interface <NUM> and TRU system <NUM>.

The TRU <NUM> may further include a renewable power source <NUM> (<FIG>) configured to recharge the batteries of the energy storage device <NUM>. One embodiment of a renewable power source <NUM> may be solar panels mounted, for example, to the outside of the top wall <NUM> of the container <NUM> (also see <FIG>). For example the renewable power source <NUM> could generate all or a portion of the needed low voltage DC power for the TRU controller <NUM>. 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 device <NUM> beyond the HV cabling going toe the AC/DC converter <NUM>.

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.

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.

Claim 1:
A transportation refrigeration unit, TRU, (<NUM>) and power system comprising:
a compressor (<NUM>) configured to compress a refrigerant, the compressor (<NUM>) having a compressor motor (<NUM>) configured to drive the compressor (<NUM>);
an evaporator heat exchanger (<NUM>) operatively coupled to the compressor (<NUM>);
an evaporator fan (<NUM>) configured to provide return airflow (<NUM>) from a return air intake (<NUM>) and flow the return airflow (<NUM>) over the evaporator heat exchanger (<NUM>);
a return air temperature, RAT, (<NUM>) sensor disposed in the return airflow (<NUM>) and configured measure the temperature of the return airflow (<NUM>);
a TRU controller (<NUM>) operably connected to the RAT sensor (<NUM>) and configured to execute a process to determine an AC power requirement for the TRU (<NUM>) based on at least the RAT;
a generator power converter (<NUM>), the generator power converter (<NUM>) configured to receive a generator three phase AC power (<NUM>) provided by an AC generator (<NUM>) and transmit a second DC power (165b);
an energy storage system (<NUM>) configured to receive the second DC power (165b) and provide a first a three phase AC power (<NUM>) and receive a second three phase AC power (<NUM>); and
a power management system (<NUM>) configured to receive the first three phase AC power (<NUM>) and direct at least a portion of the first three phase AC power (<NUM>) to the TRU (<NUM>) based at least in part on the AC power requirement;
wherein the generator power converter (<NUM>) is operably connected to the TRU controller (<NUM>), the generator power converter (<NUM>) including a voltage control function (<NUM>), a current control function (<NUM>), wherein at least the voltage control function (<NUM>) is responsive at least in part to the AC power requirement.