Adaptive charging control for transportation climate control applications

Abstract

Methods and systems are provided for operating a rechargeable energy storage source management system (RMS) to power a load when a power system is connected to an external power source. A method includes determining that a charger is connected to the external power source and the charger is enabled. The method also includes modulating a charger current from the charger to a rechargeable energy storage source management system (RMS). Further, the method includes modulating a rechargeable energy storage source (RESS) current provided by the RMS and configured for charging a RESS of the power system. Further, the method includes monitoring a state of charge (SoC) of the RESS; monitoring the RESS current provided by the charger; and comparing the RESS SoC to a desired RESS SoC threshold value. When the RESS SoC reaches the desired RESS SoC threshold, the charger current is modulated for powering the load while avoiding lowering the RESS SoC.

Description

Technical Field

[0001] The present disclosure generally relates to a power system for powering, for example, a transportation climate control system. More specifically, the present disclosure relates to a method and system for adaptively charging a rechargeable energy storage source (RESS) while powering a load. Background Art

[0002] A transport climate control system may include, for example, a transport climate control system (TCS) and / or a heating, ventilation and air conditioning (HVAC) system. A TCS is typically used to control environmental conditions (e.g., temperature, humidity, air quality, etc.) within a cargo space of a transport unit (e.g., a truck, a container (e.g., a container on a flatbed, an intermodal container, etc.), a boxcar, a semi-tractor, a passenger vehicle, or other similar transport unit). The TCS may maintain the environmental condition(s) of the cargo space to maintain cargo (e.g., produce, frozen foods, pharmaceuticals, etc.). In some embodiments, a transport unit may include an HVAC system to control the climate within a passenger space of the vehicle. Summary of the invention

[0003] The present disclosure generally relates to a power system for powering, for example, a transportation climate control system. More specifically, the present disclosure relates to a method and system for adaptively charging a RESS while powering a load.

[0004] The RESS management system (RMS) can be configured to withstand a limited number of switching between charging mode and discharging mode before power system components wear out and potentially cause power system failure. More specifically, switching between charging mode and discharging mode can induce wear of components of the RMS and cause the state of charge (SoC) of the RESS to exceed a predetermined safety threshold or drop below a service life threshold. By avoiding frequent switching between charging mode and discharging mode when powering a load, the RMS can extend the service life of the RMS, extend the service life of the RESS, and maintain the capacity of the RESS.

[0005] In addition, frequent switching between charging mode and discharging mode may increase the risk of error in the wrong mode. More complex control software may be required to mitigate this risk. Therefore, limiting the amount and / or frequency of switching between charging mode and discharging mode can increase the life of the RMS and simplify the control software.

[0006] In one embodiment, when the external power source is providing power to the power system, the RMS is configured to remain in the charging mode, regardless of whether the RESS is being charged, so that switching between the charging mode and the discharging mode can be avoided. By avoiding switching between modes, component wear caused by mode switching can be reduced, thereby improving RMS life and reliability.

[0007] Additionally, keeping the RESS in a charging mode can help maintain the RESS SoC at a desired RESS SoC while the RESS is being charged. When compared to alternative approaches where transitions of the RMS between a discharge mode and a charge mode can occur, the embodiments described herein can minimize the discharge and charge cycles of the RESS, thereby increasing the amount / percentage of time that the RMS remains at a desired RESS SoC. By increasing the amount / percentage of time that the RMS remains at a desired RESS SoC, the risk of a transport unit leaving a facility with less than a desired RESS SoC can be reduced.

[0008] Furthermore, charging and discharging the RESS at or near a desired RESS SoC of the RESS may be less energy efficient than charging the RESS at a lower SoC. Embodiments described herein may avoid / reduce the transitions between charging and discharging modes that are typically at or near a desired RESS SoC of the RESS, which may thereby improve the energy efficiency of the power system.

[0009] In one embodiment, a method for operating a RESS management system to power a load when an electric power system is connected to an external power source is disclosed. The method includes determining that a charger of the electric power system is connected to the external power source and that the charger is enabled. The method also includes modulating a charger current from the charger to a rechargeable energy storage source management system (RMS) of the electric power system. In addition, the method includes modulating a RESS current provided by the RMS and configured to charge a rechargeable energy storage source (RESS) of the electric power system. In addition, the method includes monitoring a state of charge (SoC) of the RESS; monitoring the RESS current provided by the charger; and comparing the RESS SoC to a desired RESS SoC threshold. When the RESS SoC reaches the desired RESS SoC threshold, modulating the charger current for powering the load while avoiding reducing the RESS SoC.

[0010] In another embodiment, a power system for powering a load when connected to an external power source is disclosed. The power system includes a charger, an RMS, a RESS, and a controller. The charger is configured to connect the external power source to the RMS. The RMS is configured to modulate a charger current from the charger, the charger current being configured to provide power to the power system, and the RMS is configured to modulate a RESS current, the RESS current being configured to charge the RESS. The RESS is configured to provide power to the load. The controller is configured to: determine that the charger is connected to the external power source, and is configured to determine that the charger is enabled; modulate the charger current from the charger to the RMS; modulate the RESS current provided by the RMS and configured to charge or discharge the RESS of the power system; monitor the state of charge (SoC) of the RESS; monitor the RESS current provided by the charger; compare the RESS SoC to a desired RESS SoC threshold; and when the RESS SoC reaches the desired RESS SoC threshold, modulate the charger current for powering the load while avoiding reducing the RESS SoC. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Reference is made to the accompanying drawings which form a part of this disclosure and which illustrate embodiments in which the systems and methods described in this specification may be implemented.

[0012] Figure 1A Illustrated is a perspective view of a container including a transport climate control system according to one embodiment.

[0013] Figure 1B is a perspective view of a transport climate control unit attached to a tractor according to one embodiment.

[0014] Figure 1C is a side view of a truck having a transport climate control system according to one embodiment.

[0015] Figure 1D is a side view of a van with a transportation climate control system according to one embodiment.

[0016] Figure 1E is a perspective view of a passenger vehicle including a transportation climate control system according to one embodiment.

[0017] Figure 2 is a schematic diagram of a power system that may be used to power a transportation climate control system according to one embodiment.

[0018] Figure 3AAccording to one embodiment, when the power system is supplying power to the load and charging the RESS Figure 2 Schematic control diagram of the power system shown in .

[0019] Figure 3B According to one embodiment, when the power system is supplying power to the load and limiting the current to the RESS Figure 2 Schematic control diagram of the power system shown in .

[0020] Figure 3C According to one embodiment, when the RESS is supplying power to the load Figure 2 Schematic control diagram of the power system shown in .

[0021] Figure 4A is a first part of a flowchart of a method for operating an electric power system according to an embodiment.

[0022] Figure 4B is a second part of a flowchart of a method for operating an electric power system.

[0023] Figure 5A is a graph of experimental data illustrating a method of operating an electric power system that maintains a desired state of charge while ramping down a charger current, according to one embodiment.

[0024] Figure 5B is a graph of experimental data illustrating a method of operating an electric power system to maintain a desired state of charge by ramping up a charger current to support a load, according to one embodiment.

[0025] Like reference numerals refer to like parts throughout. DETAILED DESCRIPTION

[0026] The present disclosure generally relates to a power system for powering, for example, a transportation climate control system. More specifically, the present disclosure relates to a method and system for adaptively charging a RESS while powering a load.

[0027] Transport climate control systems are typically used to control one or more environmental conditions within a climate-controlled space of a transport unit, such as, but not limited to, temperature, humidity, air quality, or a combination thereof. Examples of transport units include, but are not limited to, trucks, containers (such as, containers on flatbeds, intermodal containers, shipping containers, railroad containers, etc.), boxcars, semi-tractors, passenger vehicles (e.g., public transportation buses), or other similar transport units. Climate-controlled transport units can be used to transport perishable items, such as medicines, agricultural products, frozen foods, and meat products, and / or can be used to provide climate comfort for passengers in passenger spaces of passenger vehicles. The transport climate control system can include a steam compressor type climate control system, a heat storage type system, or any other suitable climate control system that can use a working fluid (e.g., a refrigerant, etc.). In these embodiments, the transport climate control system can include thermal components (e.g., heaters, radiators, etc.), cold plate technology, etc. The transport climate control system can include extracting power to operate other components of the transport climate control system (e.g., fans, pumps, controllers, human-machine interface devices (HMI), remote communication devices, etc.). In some embodiments, the transport climate control system includes, for example, an HVAC system for controlling the climate within a passenger space of a climate-controlled transport unit. In these embodiments, the transport climate control system may include a vapor compressor type HVAC system, a thermal storage type system, and / or any other suitable HVAC system, cold plate technology, thermal components, etc.

[0028] The transport climate control system may include a climate control unit (CCU) that is attached to the transport unit and configured to control one or more environmental conditions (e.g., temperature, humidity, air quality, etc.) within a climate-controlled space of the climate-controlled transport unit. The CCU may include, but is not limited to, a compressor, a condenser, an expansion valve, an evaporator, and one or more fans or blowers to control heat exchange between the air within the climate-controlled space and the ambient air outside the climate-controlled transport unit.

[0029] The power system may supply partial or full power to one or more electrical loads of a transport unit including a transport climate control system at a facility (such as a warehouse, power distribution site (docking station, storage station, charging station, gas station or refueling station, etc.), shipyard, supply plant, rest stop, parking infrastructure, etc.) during transport and / or when stationary. During transport, the power system may power one or more electrical loads by discharging the RESS of the power system. When stationary and connected to a grid power source, the power system may transmit power from the grid power source to power one or more electrical loads and / or charge the RESS. In some embodiments, the power system may also transmit power from the RESS to power one or more electrical loads.

[0030] It will be appreciated that it may be desirable for the transport climate control system to provide climate control when the transport unit is stationary and / or when the power system is connected to an external power source. In addition, it may be desirable for the transport climate control system to charge the RESS when one or more electrical loads are drawing power from the power system.

[0031] For example, when the climate controlled transport unit is a truck parked overnight at a rest area, the transport climate control system can provide climate control within the cab of the truck. The RESS of the electrical system can also be charged.

[0032] As defined herein, "low voltage" refers to Class A of ISO 6469-3 in an automotive environment. In particular, the maximum operating voltage is between 0V and 60V DC or between 0V and 30V AC.

[0033] As defined herein, "high voltage" refers to Class B of ISO 6469-3 in an automotive environment. In particular, the maximum operating voltage is between 60V and 1500V DC or between 30V and 1000V AC.

[0034] Figures 1A to 1E Various transport climate control systems are shown. It will be appreciated that the embodiments described herein are not limited to the examples provided below, but may be applied to any type of transport unit (e.g., trucks, containers (such as containers on flatbeds, intermodal containers, ocean containers, short load containers, etc.), boxcars, semi-tractors, passenger vehicles, or other similar transport units), etc.

[0035] Figure 1A One embodiment of an intermodal container 10 is illustrated having a transport climate control system 15 and a power system 20. The intermodal container 10 may be used across different modes of transportation including, for example, ship, rail, tractor-trailer, and the like.

[0036] The transport climate control system 15 includes a CCU 25 that provides climate control (e.g., temperature, humidity, air quality, etc.) to the climate-controlled space 12 of the intermodal container 10. The climate control system 15 also includes a programmable climate controller 30 and one or more sensors (not shown) configured to measure one or more parameters of the climate control system 15 (e.g., ambient temperature outside the intermodal container 10, spatial temperature within the climate-controlled space 12, ambient humidity outside the intermodal container 10, spatial humidity within the climate-controlled space 12, etc.) and transmit parameter data to the climate controller 30.

[0037] The CCU 25 is disposed on the front wall 14 of the intermodal container 10. In other embodiments, it will be appreciated that the CCU 25 may be disposed, for example, on the ceiling or other walls of the intermodal container 10. The CCU 25 includes a transport climate control loop (not shown) that connects, for example, a compressor, a condenser, an evaporator, and an expander (e.g., an expansion valve) to provide conditioned air within the climate-controlled space 12.

[0038] The climate controller 30 may include a single integrated control unit, or may include a distributed network of climate controller elements (not shown). The number of distributed control elements in a given network may depend on the specific application of the principles described herein. The climate controller 30 is configured to control the operation of the climate control system 15 including the transport climate control loop.

[0039] The climate control system 15 is powered by a power system 20 that can distribute power to the climate control system 15. In this embodiment, the power system 20 is a generator set that is disposed on the bottom wall 16 of the intermodal container 10 and is electrically connected to one or more components of the climate control system 15 (e.g., a compressor, one or more fans and / or blowers, a climate controller 30, one or more sensors, etc.).

[0040] In this embodiment, the power system 20 includes a housing 22 attached to a frame 23 by a mounting assembly 24. The mounting assembly 24 can extend between the housing 22 and a cross member 26 that is part of the frame 23. The mounting assembly 24 can be made of a high-strength material (e.g., steel, etc.) to rigidly attach the power system 20 to the intermodal container 10. The power system 20 includes a power system controller 35 configured to control the operation of the power system 20. Figure 2 The operation of an electric power system such as electric power system 20 is discussed in further detail with reference to FIG. 5 .

[0041] Figure 1BOne embodiment of a climate controlled transport unit 102 is illustrated attached to a tractor 103. The climate controlled transport unit 102 includes a climate control system 100 for a transport unit 105. The tractor 103 is attached to the transport unit 105 and is configured for towing the transport unit 105. Figure 1B The transport unit 105 shown is a trailer.

[0042] The transport climate control system 100 includes a CCU 110 that provides climate control (e.g., temperature, humidity, air quality, etc.) within a climate-controlled space 106 of a transport unit 105. The climate control system 100 also includes a programmable climate controller 107 and one or more sensors (not shown) configured to measure one or more parameters of the climate control system 100 (e.g., ambient temperature outside the transport unit 105, space temperature within the climate-controlled space 106, ambient humidity outside the transport unit 105, space humidity within the climate-controlled space 106, etc.) and transmit parameter data to the climate controller 107.

[0043] The CCU 110 is disposed on the front wall 108 of the transport unit 105. In other embodiments, it will be appreciated that the CCU 110 may be disposed, for example, on the ceiling or other walls of the transport unit 105. The CCU 110 includes a transport climate control loop (not shown) that connects, for example, a compressor, a condenser, an evaporator, and an expander (e.g., an expansion valve) to provide conditioned air within the climate controlled space 106.

[0044] The climate controller 107 may include a single integrated control unit 112, or may include a distributed network of climate controller elements 112, 113. The number of distributed control elements in a given network may depend on the particular application of the principles described herein. The climate controller 107 is configured to control the operation of a climate control system 100 including a transport climate control loop.

[0045] The climate control system 100 is comprised of an electrical system (e.g., see Figure 2 ) that can distribute power to the climate control system 100. In some embodiments, the power system can be a generator set (not shown) that is attached to the transport unit 105 and electrically connected to one or more components of the climate control system 100 (e.g., a compressor, one or more fans and / or blowers, a climate controller 107, one or more sensors, etc.). Figure 2 The operation of the power system is discussed in further detail with reference to FIG. 5 .

[0046] Figure 1C1 is a side view of a truck 120 having a transport climate control system 124 according to one embodiment. The truck 120 includes a climate controlled space 122 for carrying cargo. The transport climate control system 124 includes a CCU 126 mounted to a front wall 128 of the climate controlled space 122. The CCU 126 may include, among other components, a climate control loop (not shown) that connects, for example, a compressor, a condenser, an evaporator, and an expander (e.g., an expansion valve) to provide climate control within the climate controlled space 122. In one embodiment, the CCU 126 may be a transport refrigeration unit or the like.

[0047] The transport climate control system 124 also includes a programmable climate controller 125 and one or more climate control sensors (not shown) configured to measure one or more parameters of the transport climate control system 124 (e.g., ambient temperature outside the truck 120, ambient humidity outside the truck 120, compressor suction pressure, compressor discharge pressure, supply air temperature of air supplied by the CCU 126 into the climate controlled space 122, return air temperature of air returned from the climate controlled space 122 to the CCU 126, humidity within the climate controlled space 122, etc.) and transmit climate control data to the climate controller 125. The one or more climate control sensors may be positioned at various locations outside the truck 120 and / or inside the truck 120 (including within the climate controlled space 122).

[0048] The climate controller 125 is configured to control the operation of the transport climate control system 124 including components of the climate control loop. The climate controller 125 may include a single integrated control unit, or may include a distributed network of climate controller elements (not shown). The number of distributed control elements in a given network may depend on the specific application of the principles described herein. The measured parameters obtained by one or more climate control sensors may be used by the climate controller 125 to control the operation of the climate control system 124.

[0049] The climate control system 124 is comprised of an electrical system (e.g., see Figure 2 5 ), which can distribute power to the climate control system 124. In some embodiments, the power system can be a generator set (not shown) that is attached to the truck 120 and electrically connected to one or more components of the climate control system 124 (e.g., a compressor, one or more fans and / or blowers, a climate controller 125, one or more sensors, etc.). Figure 2 The operation of the power system is discussed in further detail with reference to FIG. 5 .

[0050] Figure 1DA side view of a van 130 having a transport climate control system 135 for providing climate control within a climate controlled space 132 is shown according to one embodiment. The transport climate control system 135 includes a CCU 140 mounted to a ceiling 134 of the van 130. In one embodiment, the CCU 140 may be a transport refrigeration unit, etc. The climate control system 135 also includes a programmable climate controller 145 and one or more sensors (not shown) configured to measure one or more parameters of the climate control system 135 (e.g., ambient temperature outside the van 130, spatial temperature within the climate controlled space 132, ambient humidity outside the van 130, spatial humidity within the climate controlled space 132, etc.) and transmit parameter data to the climate controller 145.

[0051] The transport climate control system 135 may include, among other components, a transport climate control loop (not shown) that connects, for example, a compressor, a condenser, an evaporator, and an expander (eg, an expansion valve) to provide climate control within the climate controlled space 132 .

[0052] Climate controller 145 may include a single integrated control unit, or may include a distributed network of climate controller elements (not shown). The number of distributed control elements in a given network may depend on the specific application of the principles described herein. Climate controller 145 is configured to control the operation of climate control system 135 including a transport climate control loop.

[0053] The climate control system 135 is comprised of an electrical system (e.g., see Figure 2 ) that can distribute power to the climate control system 135. In some embodiments, the power system can be a generator set (not shown) that is attached to the van 130 and electrically connected to one or more components of the climate control system 135 (e.g., a compressor, one or more fans and / or blowers, a climate controller 145, one or more sensors, etc.). Figure 2 The operation of the power system is discussed in further detail with reference to FIG. 5 .

[0054] Figure 1E is a perspective view of a passenger vehicle 150 including a transportation climate control system 155 according to one embodiment. Figure 1EIn the illustrated embodiment, the passenger vehicle 150 is a public transportation bus that can carry (one or more) passengers (not shown) to one or more destinations. In other embodiments, the passenger vehicle 150 can be a school bus, a railway vehicle, a subway car, or other commercial vehicle that carries passengers. Hereinafter, the term "vehicle" should be used to refer to all such passenger vehicles and should not be interpreted as limiting the scope of application to public transportation buses. The transportation climate control system 155 can provide climate control within a climate-controlled space, which in this embodiment is a passenger cabin 154.

[0055] The passenger vehicle 150 includes a frame 152, a passenger compartment 154 supported by the frame 152, wheels 153, and a compartment 156. The frame 152 includes doors 158 positioned on one side of the passenger vehicle 150. A first door 158a is positioned adjacent to the front end of the passenger vehicle 150, and a second door 158b is positioned on the frame 152 toward the rear end of the passenger vehicle 150. Each door 158 is movable between an open position and a closed position to selectively allow access to the passenger compartment 154.

[0056] The transportation climate control system 155 includes a CCU 160 mounted to the ceiling 151 of the passenger vehicle 150. In one embodiment, the CCU 160 can be an HVAC unit. The climate control system 155 also includes a programmable climate controller 165 and one or more sensors (not shown) configured to measure one or more parameters of the transportation climate control system 155 (e.g., ambient temperature outside the passenger vehicle 150, space temperature within the passenger compartment 154, ambient humidity outside the passenger vehicle 150, space humidity within the passenger compartment 154, etc.) and transmit parameter data to the climate controller 165.

[0057] The transportation climate control system 155 may include, among other components, a transportation climate control loop (not shown) that connects, for example, a compressor, a condenser, an evaporator, and an expander (eg, an expansion valve) to provide climate control within the passenger cabin 154 .

[0058] Climate controller 165 may include a single integrated control unit, or may include a distributed network of climate controller elements (not shown). The number of distributed control elements in a given network may depend on the specific application of the principles described herein. Climate controller 165 is configured to control the operation of climate control system 155 including a transport climate control loop.

[0059] The climate control system 135 is comprised of an electrical system (e.g., see Figure 2) that can distribute power to the climate control system 135. In some embodiments, the power system can be a generator set (not shown) that is attached to the passenger vehicle 150 and electrically connected to one or more components of the climate control system 155 (e.g., a compressor, one or more fans and / or blowers, a climate controller 165, one or more sensors, etc.). Figure 2 The operation of the power system is discussed in further detail with reference to FIG. 5 .

[0060] A compartment 156 is positioned adjacent to the rear end of the passenger vehicle 150, and may include an electrical system. In some embodiments, the compartment 156 may be located elsewhere on the vehicle 150 (eg, adjacent to the front end, etc.).

[0061] Figure 2 2 is a schematic diagram of an electric power system 200 according to an embodiment. The electric power system 200 may be the electric power system 200 described above. Figures 1A to 1E Any of the power systems described herein. Power system 200 manages power for a transport climate control system. In some embodiments, power system 200 may be a power system for a transport climate control system. Figures 1A to 1E The power system of any of the transportation climate control systems 15, 100, 125, 135, or 155 shown and described above.

[0062] The power system 200 supplies part or all of the power required by the transport climate control system during transport and / or stationary at facilities such as warehouses, power distribution sites (docking stations, storage stations, charging stations, gas stations or refueling stations, etc.), shipyards, supply plants, rest stops, parking infrastructure, etc. The power system 200 can be transported onboard a transport unit (e.g., transported with the transport unit, transported within the transport unit, or transported by the transport unit). When the transport climate control system is connected to an external power source, the power system 200 can be configured to control the current provided from the charger to supply part or all of the power extracted by the transport climate control system. During transport, the power system 200 can be configured to supply stored power or power generated onboard to provide part or all of the power required by one or more loads (including one or more loads of the transport climate control system).

[0063] In some embodiments, the power system 200 may include a generator set (abbreviated as "genset") configured to supply power to one or more loads associated with the transport unit, including one or more loads of a transport climate control system. The one or more loads may include any transport climate control system load, HVACR system components, lift doors, etc. Examples of transport climate control system loads may include, for example, heaters, (one or more) fans, (one or more) blowers, compressors, pumps, controllers, remote communication units, HMIs, and / or similar loads. In some embodiments, the generator set may include a combination of a prime mover (e.g., an engine, such as a diesel engine) and a motor (e.g., a generator) that can be used to generate electricity. In some embodiments, the generator set may include a combination of a RESS (e.g., a battery, such as a lithium-ion battery, a nickel metal hydride battery, a lead-acid battery, etc.) and an inverter that can be used to supply power. In some embodiments, the generator set may include a combination of a storage RESS, an inverter, a prime mover, and a motor to supply power to one or more loads.

[0064] like Figure 2 As illustrated, the power system 200 may include a charger 210 , an RMS 240 , and a RESS 250 . The power system 200 may be configured to provide power to one or more loads 260 .

[0065] The charger 210 is configured to supply power to the power system 200, which is configured to manage the power received from the charger and distribute the power to the RESS 250 and / or one or more loads 260. For example, the charger 210 can be connected to an external power source 290 for providing power to the power system 200. The external power source 290 can be a direct current (DC) power source and / or an alternating current (AC) power source. The external power source 290 can be a power source from outside the power system, such as grid power, utility power, shore power, power station, generator (e.g., gas or diesel generator), etc. For example, the charger 210 can be connected to the external power source 290 at facilities such as warehouses, power distribution sites (docking stations, storage stations, charging stations, gas stations or gas stations, etc.), shipyards, supply plants, rest stops, parking infrastructure, etc. In one embodiment, the external power source 290 may include a motor configured to supply three-phase AC power.

[0066] In some embodiments, the charger 210 may include an electrical connector configured to couple the charger 210 to an external power source 290. In one embodiment, the charger 210 may include an electrical connector configured to correspond to the external power source 290, such that an AC electrical connector may be provided for an AC external power source, and a DC connector may be provided for a DC power source. In one embodiment, the electrical connector of the charger 210 may include an optional AC electrical connection 212 (e.g., an AC plug) configured to couple the charger 210 to the external power source 290 when the external power source is configured to supply a high voltage three-phase current. The optional AC electrical connection 212 may connect an on-board AC charger 214 to the external power source 290. The on-board AC charger 214 may be configured to modulate the current received from the external power source 290. In one embodiment, the on-board AC charger 214 is configured to convert three-phase AC power from a motor such as a generator set into DC power, which may be used to charge the RESS 250 and / or power one or more loads 260.

[0067] In one embodiment, the charger 210 may include an optional DC electrical connection 216 (e.g., a DC plug) configured to couple the charger 210 to the external power source 290 when the external power source 290 is configured to supply high voltage direct current. The optional DC electrical connection 216 may be in communication with a DC charger controller 218 configured to modulate the current received from the external power source 290 and provide the current to the RMS 240.

[0068] It is understood that the high voltage power source may have a voltage equal to or approximately 460V AC, 800V DC, etc. In one embodiment, the RESS 250 may be a high voltage power source. It is also understood that in some embodiments, the charger 210 may be configured to include both an AC electrical connection 212 connected to an onboard AC charger 214 and a DC electrical connection 216 connected to a DC charger controller 218 to receive both AC power and DC power.

[0069] The charger 210 is configured to be adaptively coupled to the RMS 240. When the RMS 240 operates in a charging mode to charge the RESS 250, the charger is enabled (e.g., the charger 210 is currently connected to the RMS 240). In some embodiments, when the RMS 240 operates in a discharge mode such that the RESS 250 is configured to supply power to one or more loads 260, the charger 210 may be disabled (e.g., the charger 210 is currently disconnected from the RMS 240). In some embodiments, when the RMS 240 operates in a discharge mode such that the RESS 250 is configured to supply power to one or more loads 260, the charger 210 may be enabled (e.g., the charger 210 is currently connected to the RMS 240).

[0070] The RMS 240 is configured to modulate the flow of power between components associated with the power system 200. In one embodiment, the RMS 240 is configured to modulate the current received from the charger 210 to provide a current for charging the RESS 250 and / or to provide a current for powering one or more loads 260. It is understood that the current directed by the RMS 240 to charge or discharge the RESS 250 may be referred to as the RESS current herein. It is also understood that the current directed by the RMS 240 to power one or more loads 260 may be referred to as the load current herein. It is also understood that the current directed from the charger 210 to the RMS 240 may be referred to as the charger current herein.

[0071] In some embodiments, the RMS 240 can modulate the current from the RESS 250 and direct the modulated current to one or more loads 260. In the illustrated embodiment, the RMS 240 includes a high voltage power distribution unit (HV PDU) 242, an inverter 243, and a controller 256.

[0072] It is understood that the RMS 240 may also include switches, capacitors, ammeters, voltmeters, inductors, safety components for operating the power system 200 (e.g., fuses, surge protectors, etc.), etc. In addition, the RMS 240 may include, for example, one or more power inverters, a thermal management system, one or more power filters, etc. In some embodiments, the RMS 240 is configured to monitor the power demand from one or more loads 260. For example, when the prime mover is shut down. In addition, the RMS 240 is configured to transmit the power demand of one or more loads 260 to the power system 200.

[0073] The HV PDU 242 is configured to distribute power through the RMS 240, for example, by distributing current from the charger 210 to the RESS 250 and one or more loads 260, distributing current from the RESS 250 to one or more loads 260, and so on. The HV PDU 242 may include one or more ports configured to connect the charger 210, the RESS 250, and / or the one or more loads 260 for distributing power. For example, the HV PDU 242 may be configured to distribute power provided by the charger 210 to one or more loads 260 and / or the RESS 250; from the RESS 250 to one or more loads 260; and so on. In some embodiments, the HV PDU 242 may include a controller having a processor that controls the charger 210, charges or discharges the RESS 260, supplies power to one or more loads 260, controls the inverter 243, and so on.

[0074] The inverter 243 is configured to convert DC power into AC power. For example, the inverter 243 may convert DC current from the RESS 250 and / or the charger 210 to provide AC current to one or more loads 260 .

[0075] The controller 246 is configured to control the RMS 240, the RESS 250, the charger 210, etc. In one embodiment, the controller 246 may be a computer including one or more integrated control units and / or a plurality of integrated control units. Figure 1B Controller 246 may be a climate controller configured to adjust climate control conditions provided by one or more loads 260. Controller 246 may include, for example, Figures 1A to 1E In one embodiment, in addition or alternatively to controller 246, RMS 240 may include controller 246A operatively connected to RMS 240. Although controller 246A is Figure 2 246A is shown as being located within RMS 240, but it will be appreciated that in other embodiments, controller 246A may be located remotely from power system 200 and may be configured to communicate with power system 200 via, for example, a wired or wireless communication protocol discussed below.

[0076] RESS250 is configured to store power and / or provide power to the power system 200, for example, to provide power when the external power source 290 is not available. In some embodiments, RESS250 may include one or more battery cells, battery packs, etc. configured to provide power to one or more loads 260. RESS250 can provide DC power to one or more loads 260, and in some embodiments, provide AC power from the inverter 243. In some embodiments, RESS250 can have a battery power source with a capacity of about 40kW-hr. In one embodiment, RESS250 includes one or more lithium-ion batteries. It will be understood that the embodiments described herein can prevent RESS250 from accepting power after exceeding its designed storage capacity, thereby preventing damage to RESS250 and the risk of fire or explosion.

[0077] The RESS 250 may have a SoC that characterizes the amount of power stored in the RESS 250. The SoC may be a percentage relative to the maximum amount of energy that can be stored in the RESS 250. The maximum amount of energy that can be stored in the RESS 250 may be a number of watt-hours or kilowatt-hours characterized by the physical and / or chemical composition of the RESS. It will be appreciated that the desired RESS SoC may not be the maximum SoC of the RESS 250 in order to allow operational flexibility, provide a safety margin, maintain the life of the RESS 250, etc. The desired SoC of the RESS 250 may vary based on the application. For example, in one embodiment, the desired RESS SoC may be 90%.

[0078] It is appreciated that the RESS 250 may include a controller for receiving and discharging RESS current, balancing RESS charge between RESS cells, providing thermal management, etc. In one embodiment, the controller 246 may include a controller for the RESS 250 .

[0079] One or more loads 260 consume power to provide one or more functions of the transport unit and / or the transport climate control system. The functions of the transport climate control system may include heating, cooling, ventilation, operating any device that supports the operation of the climate control components, and the like.

[0080] In one embodiment, the one or more loads 260 include one or more thermal components 262 (e.g., heaters, (one or more) fans, (one or more) blowers, radiators, etc.), one or more transportation climate control system components 266 (e.g., compressors, evaporators, condensers, expanders, etc.). In one embodiment, the one or more loads 260 can be powered by load current through the inverter 243 based on the demand requested by the one or more loads 260. In one embodiment, the one or more loads 260 may require the current or a portion of the current supplied to the transportation climate control system to be directed from the inverter 243. The inverter 243 can convert DC power to AC power provided to the one or more loads 260. The components of the one or more loads 260 may include, for example, compressors, pumps, etc., and may require AC power to function.

[0081] Figure 3A , Figure 3B and Figure 3C According to one embodiment, Figure 2 A schematic control diagram of an electric power system 200 is shown.

[0082] The power system 200 is configured to supply power to one or more loads 260 and is operably connected to the charger 210, the RMS 240, the RESS 250, and the one or more loads 260, such as Figure 2 As shown and described above. Figure 3A and Figure 3B As shown, the RMS 240 is in electrical communication with the charger 210, the RESS 250, and one or more loads 260. In one embodiment, the charger 210 supplies a current (“charger current”) 271 to the RMS 240. The RMS 240 is configured to supply a current (“load current”) 276 to the one or more loads 260 to power the one or more loads 260. The RMS 240 may also be configured to supply a current (“RESS current”) 275 to the RESS 250 to charge the RESS 250.

[0083] In some embodiments, when the power system 200 is connected to the external power source 290, the RMS 240 can modulate the current in the power system 200 to charge the RESS 250 and supply power to one or more loads 260 by switching between a charging mode and a discharging mode. For example, in the charging mode, the RMS 240 can use the RESS current 275 to power one or more loads 260. When the state of charge (SoC) of the RESS 250 decreases below the SoC threshold, the RMS 240 can switch to the charging mode to charge the RESS 250. When the external power source 290 is providing power to the power system 200 via the charger 210, this method can alternate between the charging mode and the discharging mode for a period of time.

[0084] When the external power source 290 is able to provide power to the power system 200 via the charger 210, the RESS 250 can be charged at any non-negative charge rate (i.e., the RESS current 275 supplied by the RMS 240 can be 0A, about 0A, or higher) for a duration. The RMS 240 can be configured to power one or more loads 260 with the charger current 271, for example, by matching the load current 276 with the charger current 271.

[0085] When the RESS 250 is charged to a desired RESS SoC, then the RMS 240 may be configured to supply a lower or nominal amount of current (eg, 0A or approximately 0A) to the RESS 250 to maintain the desired RESS SoC of the RESS 250 and avoid overcharging the RESS 250 while keeping the RMS 240 in a charging mode.

[0086] It will be appreciated that, depending on the application, about 0A may be, for example, less than 2A, less than 1A, less than 0.5A, less than 0.25A, etc. Thus, over a period of time, a lower or nominal amount of RESS current 275 may increase the SoC to above the desired RESS SoC, and the RMS 240 may switch to a discharge mode to reduce the SoC to the desired RESS SoC. Thus, the frequency of switching to the discharge mode may be significantly lower than the switching frequency that occurs when the RMS 240 is constantly switching between discharging the RESS 250 (i.e., powering one or more loads 260) and charging the RESS 250. Compared to this approach, keeping the power system 200 in a charging mode and occasionally switching to a discharge mode to reduce the SoC of the RESS 250 may reduce wear and extend the life of the power system 200.

[0087] When the power system 200 is in the Figure 3A and Figure 3BIn the charging mode shown, the charger 210 is configured to supply a charger current 271 to the RMS 240. The RMS 240 is configured to supply a load current 276 to one or more loads 260. Figure 3A As shown, when the RESS 250 is below the desired RESS SoC and excess current is available from the charger 210 (i.e., the charger current 271 is greater than the amount of current drawn by the one or more loads (260)), the RMS 240 is configured to supply excess current (i.e., RESS current 275) to the RESS 250 to increase the SoC of the RESS 250. For example, when the charger current 271 is 29 amperes and the current drawn by the one or more loads (260) (i.e., load current 276) is 15 amperes, an excess current of 14 amperes (i.e., RESS current 275) may be supplied by the RMS 240 to charge the RESS 250.

[0088] like Figure 3B As shown, when too much current cannot be obtained from the charger 210 (i.e., the charger current 271 is not greater than the amount of current drawn by the one or more loads (260)), and / or the RESS is at or above the desired RESS SoC, the RMS 240 is configured to limit the current delivery to the RESS 250 (i.e., limit the RESS current 275) so that substantially all of the charger current 271 received by the RMS 240 is supplied to the one or more loads 260. For example, when the charger current 271 is 15 amperes and the current drawn by the one or more loads (260) (i.e., the load current 276) is 15 amperes, the RMS 240 limits the amount of the RESS current 275 so that the load current 276 substantially matches the charger current 271. It is understood that the RMS 240 can determine the total current draw (e.g., the sum of the RESS current 275 and the load current 276), and the RMS 240 can be configured to draw the total current draw (i.e., the charger current 271) from the charger 210, or iteratively increase the current draw by a predetermined value (e.g., 0.25A, 1A, etc.) until a threshold is met. For example, the threshold can be a charger current of 0A or about 0A. As a result, after the RESS 250 is charged to the desired RESS SoC, the RESS 250 can maintain the desired RESS SoC, and the RMS 240 can be configured to power one or more loads 260 using power supplied from the charger 210. Therefore, the RMS 240 can remain in the charging mode and avoid switching between the charging mode and the discharging mode.

[0089] like Figure 3CAs shown, when the power system 200 is in the discharge mode, the RESS 250 is configured to supply a RESS current 275 to the RMS 240, and the RESS current 275 reduces the SoC of the RESS 250. The RMS 240 is configured to supply a load current 276 to one or more loads 260. When an external power source is not available, such as during transportation, the RESS 250 can provide power to one or more loads 260. In this embodiment, the charger 210 is not enabled (e.g., the charger 210 is not currently connected to the RMS 240). However, in other embodiments, the charger 210 can be enabled in the discharge mode (e.g., the charger 210 can currently be connected to the RMS 240).

[0090] It can be understood that according to one embodiment, FIG. 3A to FIG. 3C The current amounts shown in (e.g., 29A, 14A, 15A, etc.) are merely illustrative. The current values ​​illustrated between one or more loads 260, RMS 250, charger 210, and / or RESS 250 are not intended to be limiting. The current may be any value suitable for power system 200.

[0091] Combined Figure 4A and Figure 4B A method for operating a power system (e.g., Figure 2 , FIG. 3A to FIG. 3C 200) is a flowchart of a method 400 of the power system 200 shown in FIG. The method 400 may be used in conjunction with Figures 1A to 1E The method 400 is operated together with any of the transportation climate control systems 15, 100, 125, 135, or 155 shown and described above. In the embodiments described below, the method 400 is performed by a single controller (e.g., the controller 246 of the RMS 250). However, it is understood that in other embodiments, the method 400 can be performed by one or more other controllers (e.g., a controller of the transportation climate control system, a controller of the power system, a controller of the RMS, a combination thereof, etc.).

[0092] At 410, the controller determines whether the power system is connected to an external power source (e.g., external power source 290) and whether a charger (e.g., charger 210) of the power system is enabled (e.g., whether the charger is currently connected to the RMS). When the controller determines that the power system is connected to the external power source and the charger is enabled, the RMS is set to a charging mode and the method proceeds to 420. When the controller determines that the power system is not connected to an external power source or the charger is disabled, the method proceeds to 411.

[0093] At 411 , the controller determines that method 400 is not applicable and method 400 returns to 410 to continue monitoring changes in whether the power system has been connected to an external power source and whether the charger has been enabled.

[0094] At 420, the controller determines whether the charger current is below a predetermined charger current threshold. For example, the method 400 may include comparing the charger current 271 supplied by the charger 210 or drawn by the power system 200 to a charger current threshold. The charger current threshold may be an allowable maximum current value that can be discharged by the charger and / or an allowable maximum current value that can be received by the RMS without potentially damaging the charger or the RMS and / or causing safety issues. For example, the charger current threshold may be a maximum current value determined by a manufacturer of the charger or the RMS. Exceeding the charger current threshold may damage the charger 210 and / or the RMS 240 and cause safety issues. In some embodiments, the charger current threshold may be a dynamic value determined by the controller or a static value determined during the design of a specific application. In addition, in some embodiments, the charger current threshold may be a range that may vary based on the application (e.g., ±5% of the threshold current value). When the charger current is below the charger current threshold, the method 400 proceeds to 430 (see Figure 4B ). When the charger current is not less than the charger current threshold (ie, the charger current is equal to or greater than the charger current threshold), method 400 proceeds to 425 .

[0095] At 425, the controller determines whether the current flowing from the charger to the RESS (e.g., the RESS current 275) is greater than a predetermined RESS current threshold. In one embodiment, the predetermined RESS current threshold may be an allowable maximum current value that can be received by the RESS for charging and / or an allowable maximum current value that can be discharged from the RMS to the RESS. For example, the RESS current threshold may be a maximum current value determined by a manufacturer of the RESS or the RMS. The RESS current threshold may include a threshold current value for charging the RESS. In some embodiments, the RESS current threshold may be a dynamic value determined by the controller or a static value determined during the design of a specific application. In addition, in some embodiments, the RESS current threshold may be a range that may vary based on the application (e.g., ±5% of the threshold current value). Exceeding the RESS current threshold may damage the RESS and / or the RMS and cause safety issues.

[0096] When the current flowing from the charger to the RESS is not greater than the predetermined RESS current threshold, method 400 proceeds to 454 . When the current flowing from the charger to the RESS is greater than the predetermined RESS current threshold, method 400 proceeds to 437 .

[0097] At 437, the controller determines whether the SoC of the RESS is greater than or equal to the expected RESS SoC. In one embodiment, the expected RESS SoC may be the maximum expected RESS SoC determined by the RESS manufacturer, the assembler of the power system, etc. In some embodiments, the expected RESS SoC may be a dynamic value determined by the controller or a static value determined during the design of a specific application. In addition, in some embodiments, the expected RESS SoC may be a range that may vary based on the application (e.g., ±5% of a threshold SoC value). When the RESS SoC is greater than or equal to the expected RESS SoC, the method 400 proceeds to 456. When the RESS SoC is not greater than or equal to the expected RESS SoC, the method 400 proceeds to 454.

[0098] At 430, the controller determines whether the RESS is discharging, for example, to supply power to one or more loads (eg, one or more loads 260). It is understood that the controller may determine the discharging or charging of the RESS through a controller of the RESS, a current sensor, etc.

[0099] When the controller determines that the RESS is discharging, method 400 proceeds to 440. When method 400 determines that the RESS is not discharging, method 400 proceeds to 435.

[0100] At 435, the controller determines whether the current flowing from the charger to the RESS (e.g., the RESS current 275) is less than a charging current threshold. The charging current threshold may be the maximum current allowable for safely charging the RESS. For example, the charging current threshold may be the maximum safe current determined by the manufacturer of the RESS or RMS. Exceeding the charging current threshold may damage the RESS and / or RMS and cause safety issues. In one embodiment, the charging current threshold may be the same as the RESS current threshold at 425. In some embodiments, the charging current threshold may be a dynamic value determined by the controller or a static value determined during the design of a specific application. In addition, in some embodiments, the charging current threshold may be a range that may vary based on the application (e.g., ±5% of the threshold current value).

[0101] When the current flowing from the charger to the RESS is less than the charging current threshold, method 400 proceeds to 445 . When the current flowing from the charger to the RESS is not less than the charging current threshold, method 400 proceeds to 456 .

[0102] At 440 and 445, the controller determines whether the SoC of the RESS is greater than or equal to the expected RESS SoC. In one embodiment, the expected RESS SoC may be a maximum safe SoC determined by the RESS manufacturer, the assembler of the power system, etc. In some embodiments, the expected RESS SoC may be a dynamic value determined by the controller or a static value determined during the design of a specific application. Furthermore, in some embodiments, the expected RESS SoC may be a range that may vary based on the application (e.g., ±5% of a threshold SoC value).

[0103] At 440 , when the SoC of the RESS is greater than or equal to the expected RESS SoC, the method 400 proceeds to 454 . When the SoC of the RESS is not greater than or equal to the expected RESS SoC, the method 400 proceeds to 450 .

[0104] At 445 , when the SoC of the RESS is greater than or equal to the expected RESS SoC, the method 400 proceeds to 456 . When the SoC of the RESS is not greater than or equal to the expected RESS SoC, the method 400 proceeds to 450 .

[0105] At 450, the controller increases the charger current (e.g., charger current 271) output, for example, by commanding the charger to increase the charger's current output. In some embodiments, the charger may increase the charger's current output by an amount calculated, for example, based on the measured current value. For example, the charger current may be set to the lower of: a maximum current that the charger can provide; or a maximum current that the RESS can safely accept and add to the current drawn by the load (e.g., load current 276). In other embodiments, the charger may increase the charger's current by, for example, predetermined intervals (e.g., 0.1A, 0.2A, 0.25A, 0.5A, 1.0A, etc.).

[0106] At 454 , the controller does not change the charger current output.

[0107] At 456, the controller reduces the charger current (e.g., charger current 271) output, for example, by commanding the charger to reduce the current output of the charger. In some embodiments, the charger may reduce the current output of the charger by an amount calculated, for example, based on the measured current value. For example, the charger current may be set to the amount of current drawn by the load (e.g., load current 276). The amount of current drawn by the load may be measured or calculated based on other currents (e.g., load current 276 plus RESS current 275). In other embodiments, the charger may reduce the current output of the charger by, for example, predetermined intervals (e.g., 0.1A, 0.2A, 0.25A, 0.5A, 1.0A, etc.).

[0108] After 450 , 454 , or 456 , method 400 returns to 410 to continue monitoring and operating the power system, such as in response to changes in power drawn by one or more loads, changes in current to the RESS, SoC, charger current, and the like.

[0109] In one embodiment, to increase the charger current output at 450 or to decrease the charger current output at 456, the method 400 may calculate the expected charger current required by the power system based on the load current (e.g., the load current 276) and the RESS current (e.g., the RESS current 275). The method 300 may then determine a charger set point based on the expected charger current and adjust (e.g., increase or decrease) the charger set point to provide the expected charger current. The method 300 then sets the charger to the charger set point determined based on the expected charger current.

[0110] In another embodiment, the method 300 may iteratively adjust (e.g., increase or decrease) the charger set point by an amount calculated based on the current measurement or by a predetermined interval. The predetermined interval may be 2A or less (e.g., 1A, 0.5A, 0.25A, 0.2A, 0.1A, etc.). It will be appreciated that each iteration may occur at a predetermined frequency (e.g., 1 iteration per second or faster) such that the charger 210 may reach the charger set point calculated based on the expected charger current in an amount of time comparable to the above-described calculated embodiment.

[0111] It will also be appreciated that the power demand from one or more loads can fluctuate rapidly over time. The iterative approach determines adjustments in each iteration based on real-time SoC, charger current, etc. Therefore, the iterative approach can track changes in power demand while consuming fewer computing resources overall compared to the above-described calculation methods. In some embodiments, the power demand from (one or more) loads can be calculated based on calculating the current demand from the (one or more) loads by subtracting the amount of current directed to the RESS from the amount of current provided by the charger. In some embodiments, the power demand from (one or more) loads can be calculated by measuring the current drawn by each of the one or more loads.

[0112] Figure 5A and Figure 5B 4 is an experimental data showing the method 400 according to one embodiment. Figure 5A and Figure 5B The graphs of are merely examples illustrating the corresponding RESS current, RESS SoC, charger current output, load demand(s) over a period of time, where the power drawn by the load(s) varies over time.

[0113] exist Figure 5A and Figure 5B , the RESS current at 510 is shown in amperes. Positive current values ​​indicate RESS charging. In this embodiment, the RESS is a high voltage battery. Negative current values ​​indicate RESS discharging, such as powering (one or more) loads (e.g., a transportation climate control system).

[0114] The RESS SoC at 530 is shown as a percentage, where 0% means the RESS has no useful charge for providing power and 100% means the RESS is at or near a desired RESS SoC (eg, maximum safe RESS SoC). In the illustrated example, the desired RESS SoC is 90.0%.

[0115] The charger current output at 550 is shown in amperes. A positive current value indicates that the charger current output is provided to the power system. The load(s) at 570 are shown in kilowatts (kW).

[0116] The horizontal axis shows time in seconds.

[0117] Figure 5A It is shown that in response to the RESS having reached a desired RESS SoC (eg, 90%) and the load demand is reduced or shut down, the RMS draws less current (eg, charger current).

[0118] like Figure 5A As shown, the RESS SoC is below 90% before the time point at 501. The load(s) draw approximately 10 kW. The charger current output is approximately 30 A. The charger provides current to the RMS to charge the RESS.

[0119] At approximately the time point at 501, the RESS SoC reaches the desired RESS SoC. At 502, the charger current output is gradually reduced so that the RESS current is reduced to 0A or approximately 0A, and the load(s) are primarily powered by the charger (via, for example, an external power source) to avoid frequent discharges of the RESS. At 503 (at approximately the 810 second point), the load(s) no longer require power and draw approximately 0kW. At 504, the charger current output is gradually reduced to prevent overcharging of the RESS.

[0120] Figure 5B Adjusting the charger current output to meet the power drawn from the load(s) and / or the power required to charge the RESS is shown.

[0121] like Figure 5BAs shown, at about 521, the RESS SoC drops below 90%, where the RESS has 90% of the desired RESS SoC and the load(s) remain disconnected or do not require power. The charger current output gradually increases to provide current to the RMS, and the RESS receives a portion of the charger current to charge the RESS.

[0122] At approximately 523, the RESS is charged to the desired RESS SoC, and the load(s) require power. Rather than extracting power from the RESS, the charger current output is increased to track the power drawn by the load(s). Between approximately 522 and 524, the charger current output fluctuates and follows the net power draw between the RESS and the load(s), such that discharging the RESS is avoided or reduced compared to powering the load(s) by switching between discharge mode and charge mode.

[0123] Understandably, Figure 5A and Figure 5B The data shown in is data collected from an experimental system. Power is provided primarily from the charger to the load(s) by varying the charger current output, rather than by cycling the RESS to discharge and recharge at a certain threshold. Figure 4A and Figure 4B The method 400 described in the can reduce the number of transitions between discharge mode and charge mode, extend the life of components, etc. For example, compared to a method of cycling the RESS to discharge current to (one or more) loads until the RESS SoC reaches a threshold (e.g., 85%) and then charging the RESS to a desired RESS SoC (e.g., 90%) to power (one or more) loads, for method 400, when the RESS is charged, the method 400 can maintain the RESS SoC at the desired RESS SoC. This can reduce the risk that, for example, when an operator disconnects the power system from an external power source, the RESS is not at the desired RESS SoC, causing the operator to potentially drive away with less than a fully charged charge. In addition, by maintaining the RESS in charge mode when the power system is connected to an external power source, the wear of components associated with switching between charge mode and discharge mode can be greatly reduced, thereby extending the expected life of the RMS and the entire power system, and ensuring that the RESS is at the desired RESS SoC when there is no electrical connection to the external power source.

[0124] aspect:

[0125] Note that any of aspects 1 to 7 may be combined with any of aspects 8 to 15.

[0126] Aspect 1. A method for operating an electric power system that is supplying power to a load when the electric power system is connected to an external power source, the method comprising:

[0127] determining that a charger of the power system is connected to the external power source and the charger is enabled;

[0128] modulating a charger current from the charger to a rechargeable energy storage source management system (RMS) of the power system;

[0129] modulating a rechargeable energy storage source (RESS) current provided by the RMS and configured to charge a RESS of the power system;

[0130] Monitor the state of charge (SoC) of the RESS;

[0131] monitoring the RESS current provided by the charger;

[0132] comparing the RESS SoC to a desired RESS SoC threshold; and

[0133] When the RESS SoC reaches the desired RESS SoC threshold, the charger current is modulated for powering the load while avoiding decreasing the RESS SoC.

[0134] Aspect 2. The method according to aspect 1 further comprises: when it is determined that the RESS SoC is greater than or equal to the expected RESS SoC threshold, modulating the charger current from the charger to the RMS to supply approximately 0 A for charging the RESS.

[0135] Aspect 3. The method according to any one of aspects 1 and 2 further includes: when the RESS current is discharged and the RESS SoC is lower than the expected RESS SoC threshold, commanding the charger to increase the charger current output to the RMS.

[0136] Aspect 4. The method according to any one of aspects 1 to 3 further comprises: when the charger current exceeds a charger threshold, commanding the charger to reduce the charger current.

[0137] Aspect 5. The method according to any one of aspects 1 to 4, further comprising: when the RESS current exceeds a RESS current threshold, commanding the charger to reduce the charger current.

[0138] Aspect 6. The method according to any one of aspects 1 to 5, wherein the RESS comprises a lithium-ion battery.

[0139] Aspect 7. The method according to any one of aspects 1 to 6, wherein modulating the charger current comprises: increasing or decreasing the charger current output at predetermined intervals.

[0140] Aspect 8. A power system for supplying power to a load when connected to an external power source, the power system comprising:

[0141] a charger configured to connect the external power source to a rechargeable energy storage source management system (RMS);

[0142] an RMS configured to modulate a charger current from the charger, the charger current configured to provide power to the power system, and the RMS configured to modulate a rechargeable energy storage source (RESS) current, the RESS current configured to charge or discharge the RESS;

[0143] A RESS configured to provide power to the load; and

[0144] A controller configured to:

[0145] determining that the charger is connected to the external power source, and being configured to determine that the charger is enabled;

[0146] modulating the charger current from the charger to the RMS;

[0147] modulating the RESS current provided by the RMS and configured to charge a RESS of the power system;

[0148] Monitor the state of charge (SoC) of the RESS;

[0149] monitoring the RESS current provided by the charger;

[0150] comparing the RESS SoC to a desired RESS SoC threshold; and

[0151] When the RESS SoC reaches the desired RESS SoC threshold, the charger current is modulated for powering the load while avoiding decreasing the RESS SoC.

[0152] Aspect 9. The power system of aspect 8, wherein the controller is configured to modulate the charger current from the charger to the RMS to supply approximately 0 A for charging the RESS when it is determined that the RESS SoC is greater than or equal to the desired RESS SoC threshold.

[0153] Aspect 10. The power system according to any one of aspects 8 and 9, wherein the controller is configured to: command the charger to increase the charger current output to the RMS when the RESS current is discharged and the RESS SoC is lower than the desired RESS SoC threshold.

[0154] Aspect 11. The power system according to any one of aspects 8 to 10, wherein the controller is configured to command the charger to reduce the charger current when the charger current exceeds a charger current threshold.

[0155] Aspect 12. The power system according to any one of aspects 8 to 11, wherein the controller is configured to command the charger to reduce the charger current when the RESS current exceeds a RESS current threshold.

[0156] Aspect 13. The power system according to any one of aspects 8 to 12, wherein the RESS comprises a lithium-ion battery.

[0157] Aspect 14. The power system according to any one of aspects 8 to 13, wherein the controller is configured to modulate the charger current by increasing or decreasing the charger current output by a calculated amount.

[0158] Aspect 15. The power system of any one of aspects 8 to 14, wherein the load is a transportation climate control system.

[0159] The terms used in this specification are intended to describe specific embodiments and are not intended to be limiting. Unless otherwise expressly stated, the terms "a", "an", "said", "the" also include plural forms. The terms "include" and / or "comprise" when used in this specification specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or parts.

[0160] With respect to the foregoing description, it should be understood that changes may be made in detail, especially in the construction materials employed and the shapes, sizes and arrangements of parts without departing from the scope of the present disclosure. The specification and described embodiments are merely exemplary, with the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A method for operating an electric power system that is supplying power to a load when the electric power system is connected to an external power source, the method comprising: determining that a charger of the power system is connected to the external power source and the charger is enabled; modulating a charger current from the charger to a rechargeable energy storage source management system (RMS) of the power system; modulating a rechargeable energy storage source (RESS) current provided by the RMS and configured to charge a RESS of the power system; Monitor the state of charge (SoC) of the RESS; monitoring the RESS current provided by the charger; comparing the RESS SoC to a desired RESS SoC threshold; as well as When the RESS SoC reaches the desired RESS SoC threshold, the charger current is modulated to power the load while avoiding degrading the RESS SoC.

2. The method according to claim 1, further comprising: When it is determined that the RESS SoC is greater than or equal to the desired RESS SoC threshold, the charger current from the charger to the RMS is modulated to supply approximately 0 A for charging the RESS.

3. The method according to any one of claims 1 and 2, further comprising: The charger is commanded to increase the charger current output to the RMS while the RESS current is discharging and while the RESS SoC is below the desired RESS SoC threshold.

4. The method according to any one of claims 1 and 2, further comprising: When the charger current exceeds a charger threshold, the charger is commanded to reduce the charger current.

5. The method according to any one of claims 1 and 2, further comprising: When the RESS current exceeds a RESS current threshold, the charger is commanded to reduce the charger current.

6. The method according to any one of claims 1 and 2, wherein: The RESS includes a lithium-ion battery.

7. The method according to any one of claims 1 and 2, wherein: Modulating the charger current includes increasing or decreasing the charger current output at predetermined intervals.

8. A power system for supplying power to a load when connected to an external power source, the power system comprising: a charger configured to connect the external power source to a rechargeable energy storage source management system (RMS); an RMS configured to modulate a charger current from the charger, the charger current configured to provide power to the power system, and the RMS configured to modulate a rechargeable energy storage source (RESS) current, the RESS current configured to charge or discharge the RESS; A RESS configured to provide power to the load; and A controller configured to: determining that the charger is connected to the external power source, and being configured to determine that the charger is enabled; modulating the charger current from the charger to the RMS; modulating the RESS current provided by the RMS and configured to charge a RESS of the power system; Monitor the state of charge (SoC) of the RESS; monitoring the RESS current provided by the charger; comparing the RESS SoC to a desired RESS SoC threshold; as well as When the RESS SoC reaches the desired RESS SoC threshold, the charger current is modulated to power the load while avoiding degrading the RESS SoC.

9. The power system according to claim 8, wherein: The controller is configured to modulate the charger current from the charger to the RMS to supply approximately 0 A for charging the RESS when it is determined that the RESS SoC is greater than or equal to the desired RESS SoC threshold.

10. The power system according to any one of claims 8 and 9, wherein: The controller is configured to command the charger to increase the charger current output to the RMS when the RESS current is discharging and the RESS SoC is below the desired RESS SoC threshold.

11. The power system according to any one of claims 8 and 9, wherein: The controller is configured to command the charger to reduce the charger current when the charger current exceeds a charger current threshold.

12. The power system according to any one of claims 8 and 9, wherein: The controller is configured to command the charger to reduce the charger current when the RESS current exceeds a RESS current threshold.

13. The power system according to any one of claims 8 and 9, wherein: The RESS includes a lithium-ion battery.

14. The power system according to any one of claims 8 and 9, wherein: The controller is configured to modulate the charger current by increasing or decreasing the charger current output by a calculated amount.

15. The power system according to any one of claims 8 and 9, wherein: The load is a transport climate control system.

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